Researchers Database

TAKAMATA Akira

FacultyFaculty Division of Human Life and Environmental Sciences Research Group of Environmental Health
PositionProfessor
Last Updated :2022/10/05

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Profile and Settings

  • Name (Japanese)

    Takamata
  • Name (Kana)

    Akira

Degree

  • Ph. D (Physiology), Kyoto Prefectural University of Medicine

Research Interests

  • 浮腫
  • 内皮機能
  • アンギオテンシンII
  • 骨格筋血流調節
  • 飲水行動
  • 体温調節
  • 体液調節
  • 摂食行動
  • 生体リズム
  • female reproductive hormones

Research Areas

  • Life sciences, Nutrition and health science
  • Life sciences, Physiology
  • Humanities & social sciences, Home economics, lifestyle science

Research Experience

  • 2007, 9999, Nara Women's University, Faculty of Human Life and Environment
  • 2007, 9999, Professor, Nara Women's University
  • 2016, 2016, ジョン・ピアス研究所、イェール大学産婦人科学・生殖科学 客員教授
  • 2016, 2016, Visiting Professor, John B. Pierce Laboratory, and Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine
  • 2002, 2007, Nara Women's University, Faculty of Human Life and Environment
  • 2002, 2007, Associate Professor, Nara Women's University
  • 1994, 2002, Kyoto Prefectural University of Medicine
  • 1994, 2002, Assistant Professor, Department of Physiology, Kyoto Prefectural University of Medicine
  • 1991, 1994, ジョン ピアス研究所、イェール大学医学部 博士研究員
  • 1991, 1994, Postdoctoral Associate, John B. Pierce Laboratory, and Yale University School of Medicine

Association Memberships

  • 日本繊維製品消費科学学会
  • JAPANESE SOCIETY OF BIOMETEOROLOGY
  • JAPAN SOCIETY OF NUTRITION AND FOOD SCIENCE
  • 米国生理学会
  • THE PHYSIOLOGICAL SOCIETY OF JAPAN
  • The Japan Research Association for Textile End-Users
  • American Physiological Society

Ⅱ.研究活動実績

Published Papers

  • Refereed, Nutrients, MDPI AG, Endogenous Androgens Diminish Food Intake and Activation of Orexin A Neurons in Response to Reduced Glucose Availability in Male Rats, Akira Takamata; Yuri Nishimura; Ayano Oka; Mayuna Nagata; Natsumi Kosugi; Sayaka Eguchi; Hiroko Negishi; Keiko Morimoto, Sex steroids modify feeding behavior and body weight regulation, and androgen reportedly augments food intake and body weight gain. To elucidate the role of endogenous androgens in the feeding regulation induced by reduced glucose availability, we examined the effect of gonadectomy (orchiectomy) on food intake and orexin A neuron’s activity in the lateral hypothalamic/perifornical area (LH/PFA) in response to reduced glucose availability (glucoprivation) induced by 2-deoxy-d-glucose (2DG) administration in male rats. Rats (7W) were bilaterally orchiectomized (ORX group) or sham operated (Sham group). Seventeen days after the surgery, food intake response to 2DG (400 mg/kg, i.v.) was measured for 4 h after the infusion. The same experiment was performed for the immunohistochemical examination of c-Fos-expressing orexin A neurons in the LH/PFA and c-Fos expression in the arcuate nucleus (Arc). Food intake induced by glucoprivation was greater in the ORX group than the Sham group, and the glucoprivation-induced food intake was inversely correlated with plasma testosterone concentration. Glucoprivation stimulated c-Fos expression of the orexin A neurons at the LH/PFA and c-Fos expression in the dorsomedial Arc. The number and percentage of c-Fos-expressing orexin A neurons in the LH/PFA and c-Fos expression in the dorsomedial Arc were significantly higher in the ORX group than the Sham group. This indicates that endogenous androgen, possibly testosterone, diminishes the food intake induced by reduced glucose availability, possibly via the attenuated activity of orexin A neuron in the LH/PFA and neurons in the dorsomedial Arc., 15 Mar. 2022, 14, 6, 1235, 1235, Scientific journal, True, True
  • Refereed, Physiological reports, Estradiol replacement improves high-fat diet-induced insulin resistance in ovariectomized rats., Naoko Yokota-Nakagi; Sayo Omoto; Shoko Tazumi; Mizuho Kawakami; Akira Takamata; Keiko Morimoto, The role of 17β-estradiol (E2) in high-fat diet (HFD)-induced alteration of the protein kinase B (Akt) signaling pathway in ovariectomized (OVX) rats is unclear. Therefore, we examined whether chronic estrogen replacement restores HFD-induced impairment in insulin sensitivity by its effects concomitant with alterations in the Akt isoform 2 (Akt2) and Akt substrate of 160 kDa (AS160) phosphorylation in muscles of OVX rats. Nine-week-old female Wistar rats underwent ovariectomy under anesthesia; after 4 weeks, subcutaneous implantation of either E2 or placebo (PL) pellets was performed, and HFD feeding was initiated. Intravenous glucose tolerance tests were performed to assess insulin sensitivity. Following insulin injection into rats' portal vein, the liver and gastrocnemius muscle were dissected for insulin signaling analysis. We observed that HFD increased energy intake and body weight in the PL group; however, it was temporarily decreased in the E2 group. Adipose tissue accumulation was larger in HFD-fed rats than in normal chow diet (NCD)-fed rats in the PL group; however, this difference was not observed in the E2 group. HFD reduced insulin sensitivity in the PL group only. In vivo insulin stimulation increased Akt2 phosphorylation in the muscles of NCD-fed rats in both groups. In contrast, HFD affected insulin-stimulated phosphorylation of Akt2 and AS160 in the muscles of rats in the PL group but not in the E2 group. Our data suggest that E2 replacement improves HFD-induced insulin resistance, and this effect is accompanied by the alterations in the Akt2 and AS160 phosphorylation in insulin-stimulated muscles of OVX rats., Mar. 2022, 10, 5, e15193, Scientific journal, True
  • Refereed, Nutrients, Estradiol Replacement Improves High-Fat Diet-Induced Obesity by Suppressing the Action of Ghrelin in Ovariectomized Rats., Naoko Yokota-Nakagi; Haruka Takahashi; Mizuho Kawakami; Akira Takamata; Yuki Uchida; Keiko Morimoto, This study aims to investigate the effects of estradiol replacement on the orexigenic action of ghrelin in ovariectomized (OVX) obese rats fed with a high-fat diet (HFD). Four weeks after OVX at 9 weeks of age, Wistar rats were subcutaneously implanted with either 17β-estradiol (E2) or placebo (Pla) pellets and started on HFD feeding. After 4 weeks, growth hormone-releasing peptide (GHRP)-6, a growth hormone secretagogue receptor (GHSR) agonist injected intraperitoneally, induced changes in HFD intake, and c-Fos-positive neurons in the hypothalamic arcuate nucleus (ARC) were measured in both groups. The ghrelin protein and mRNA levels, as well as GHSR protein in stomach, were analyzed by Western blotting and real-time PCR. HFD increased energy intake and body weight in the Pla group, while it temporarily reduced these in the E2 group. GHRP-6 enhanced HFD intake and activated neurons in the ARC only in the Pla group. Furthermore, gastric ghrelin and GHSR protein levels were lower in the E2 group than in the Pla group, but plasma acyl ghrelin levels were similar in both groups. Our results suggest that E2 replacement improves obesity by inhibiting the orexigenic action of ghrelin via downregulation of ghrelin and its receptor in stomach in HFD-fed OVX rats., 26 Mar. 2020, 12, 4, Scientific journal, True
  • Refereed, Nutrients, MDPI AG, Fluoxetine Mimics the Anorectic Action of Estrogen and Its Regulation of Circadian Feeding in Ovariectomized Female Rats, Yuri Nishimura; Kaori Mabuchi; Natsumi Omura; Ayako Igarashi; Megumi Miura; Nanako Mima; Hiroko Negishi; Keiko Morimoto; Akira Takamata, Our previous study demonstrated that chronic estrogen replacement in ovariectomized rats reduces food intake and augments c-Fos expression in the suprachiasmatic nucleus (SCN), specifically during the light phase. Here, we hypothesized that serotonergic neurons in the central nervous system (CNS), which have anorectic action and play a role in regulating circadian rhythm, mediate the light phase-specific anorectic action of estrogen, and that selective serotonin reuptake inhibitors (SSRIs) mimic the hypophagic action of estrogen. Female Wistar rats were ovariectomized and treated with estradiol (E2) or cholesterol by subcutaneously implanting a silicon capsule containing E2 or cholesterol. Then, half of the cholesterol-treated rats were injected with the SSRI fluoxetine (5 mg/kg) (FLX group), while the remaining rats in the cholesterol-treated group (CON group) and all those in the E2 group were injected with saline subcutaneously twice daily at the onsets of the light and dark phases. Both E2 and FLX reduced food intake during the light phase but not the dark phase, and reduced body weight gain. In addition, both E2 and FLX augmented the c-Fos expression in the SCN, specifically during the light phase. These data indicate that FLX exerts estrogen-like antiobesity and hypophagic actions by modifying circadian feeding patterns, and suggest that estrogen regulates circadian feeding rhythm via serotonergic neurons in the CNS., 22 Mar. 2020, 12, 3, 849, 849, Scientific journal, True, True
  • Refereed, The journal of physiological sciences : JPS, Endurance running exercise is an effective alternative to estradiol replacement for restoring hyperglycemia through TBC1D1/GLUT4 pathway in skeletal muscle of ovariectomized rats., Mizuho Kawakami; Naoko Yokota-Nakagi; Akira Takamata; Keiko Morimoto, Menopause is a risk factor for impaired glucose metabolism. Alternative treatment of estrogen for postmenopausal women is required. The present study was designed to investigate the effects of 5-week endurance running exercise (Ex) by treadmill on hyperglycemia and signal pathway components mediating glucose transport in ovariectomized (OVX) placebo-treated rats, compared with 4-week 17β-estradiol (E2) replacement or pair-feeding (PF) to the E2 group. Ex improved the hyperglycemia and insulin resistance index in OVX rats as much as E2 or PF did. However, Ex had no effect on body weight gain in the OVX rats. Moreover, Ex enhanced the levels of GLUT4 and phospho-TBC1D1 proteins in the gastrocnemius of the OVX rats, but E2 or PF did not. Instead, the E2 increased the Akt2/AS160 expression and activation in the OVX rats. This study suggests that endurance Ex training restored hyperglycemia through the TBC1D1/GLUT4 pathway in muscle by an alternative mechanism to E2 replacement., Nov. 2019, 69, 6, 1029, 1040, Scientific journal, False
  • Not Refereed, 食と医療, 水分補給による熱中症予防の生理学的メカニズム, 鷹股 亮, Jul. 2019, 10, 15, 22
  • Refereed, The journal of physiological sciences : JPS, The effect of menstrual cycle phase on foot skin temperature during mild local cooling in young women., Yuki Uchida; Koyuki Atsumi; Akira Takamata; Keiko Morimoto, Japanese women can experience a sensation of cold feet in daily life. It is possible that this sensation of coldness in feet may be associated with female hormones, but to date the effect of menstrual cycle phase on the skin temperature (Tsk) of the foot during local cooling is unknown. We therefore examined Tsk and partial cutaneous blood flow in the foot during the follicular (F) and luteal (L) phases of the menstrual cycle in women experiencing local cooling. Tsk was measured in the toes and the dorsum of the left foot using infrared thermography, while cutaneous blood flow was evaluated in the big toe of the left foot using laser Doppler flowmetry (LDF), both at 28 °C. Mild local cooling (24.7 °C) was then applied for 30 min to the right foot. During cooling of the right foot, no significant differences in Tsk were observed between the F and L phases in either the toes of the left foot or the dorsum of the left foot of all subjects. However, cutaneous blood flow determined by LDF in the big toe of the left foot was greater in the F phase than in the L phase. These results suggest that the menstrual cycle phase did not affect Tsk in the foot, but it did affect cutaneous blood flow in the big toe during mild local cooling., Jan. 2019, 69, 1, 151, 157, Scientific journal, False
  • Refereed, American journal of physiology. Endocrinology and metabolism, Estrogen replacement enhances insulin-induced AS160 activation and improves insulin sensitivity in ovariectomized rats., Mizuho Kawakami; Naoko Yokota-Nakagi; Masami Uji; Ken-Ichi Yoshida; Shoko Tazumi; Akira Takamata; Yuki Uchida; Keiko Morimoto, Menopause predisposes women to impaired glucose metabolism, but the role of estrogen remains unclear. In this study, we examined the effects of chronic estrogen replacement on whole body insulin sensitivity and insulin signaling in ovariectomized rats. Female Wistar rats aged 9 wk were ovariectomized under anesthesia. After 4 wk, pellets containing either 17β-estradiol (E2) or placebo (Pla) were subcutaneously implanted in the rats. After 4 wk of treatment, the intra-abdominal fat accumulation was greater in the Pla group than that in the E2 group. Hyperinsulinemic-euglycemic clamp analysis and intravenous glucose tolerance test revealed that insulin sensitivity was significantly lower in the Pla group than in the E2 group. In addition, Western blotting showed that in vivo insulin stimulation increased protein kinase B (Akt) phosphorylation to a similar degree in the gastrocnemius and liver of both groups, but phosphorylated Akt2 Ser474 was enhanced in the muscle of the E2 group compared with the Pla group. Moreover, insulin-stimulated phosphorylation of Akt substrate of 160 kDa (AS160) Thr642 was observed only in the E2 group, resulting in the difference between the two groups. Additionally, AS160 protein and mRNA levels were higher in muscle of the E2 group than the Pla group. In contrast, E2 replacement had no effect on glucose transporter 4 protein levels in muscle and glycogen synthase kinase-3β in muscle and liver. These results suggest that estrogen replacement improves insulin sensitivity by activating the Akt2/AS160 pathway in the insulin-stimulated muscle of ovariectomized rats., 01 Dec. 2018, 315, 6, E1296-E1304, E1304, Scientific journal, True
  • Refereed, American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Blood pressure predicts endothelial function and the effects of ethinyl estradiol exposure in young women, Tessa E. Adler; Charlotte W. Usselman; Akira Takamata; Nina S. Stachenfeld, Hypertension, obesity, and endothelial function predict cardiovascular disease in women, and these factors are interrelated. We hypothesized that hypertension and obesity are associated with endothelial dysfunction in young women and that short-term ethinyl estradiol exposure mitigates this dysfunction. We examined flow-mediated dilation (FMD) responses before and during 7 days of oral ethinyl estradiol (30 µg/day) in 19 women (25 ± 5, 18–35 yr). We divided our sample into two groups based on two criteria: blood pressure and obesity. Women were divided into normal blood pressure (NBP; mean arterial pressure range: 78–91 mmHg, n = 7) and high blood pressure (HBP; mean arterial pressure range: 95–113 mmHg, n = 9) groups. We also stratified our subjects by body composition (lean: 18–31%, n = 8; obese: 38–59%, n = 9). We evaluated brachial FMD after two distinct shear stress stimuli: occlusion alone and occlusion with ischemic handgrip exercise. Obesity was unrelated to both FMD responses. Before ethinyl estradiol administration, the HBP group had blunted ischemic exercise responses relative to the NBP group (8.0 ± 3.5 vs. 12.3 ± 3.2%, respectively, P = 0.05). However, during ethinyl estradiol administration, ischemic exercise responses increased in the HBP group (12.8 ± 6.1%, P = 0.04) but decreased in the NBP group (5.6 ± 2.4%, P = 0.01). Standard FMD did not reveal differences between groups. In summary, 1) moderate HBP predicted endothelial impairment, 2) ethinyl estradiol administration had divergent effects on FMD in women with NBP versus HBP, and 3) enhanced FMD (ischemic handgrip exercise) revealed differences in endothelial function, whereas standard FMD (occlusion alone) did not. NEW & NOTEWORTHY We are the first to show that mild hypertension is a stronger predictor of endothelial dysfunction than obesity in healthy women without overt cardiovascular dysfunction. Importantly, the standard 5-min flow-mediated vasodilation stimulus did not detect endothelial dysfunction in our healthy population; only an enhanced ischemic handgrip exercise shear stress stimulus detected endothelial impairment. Estradiol administration increased flow-mediated dilation in women with high blood pressure, so it may be a therapeutic intervention to improve endothelial function., 01 Oct. 2018, 315, 4, H925, H933, Scientific journal, True, True
  • Refereed, American journal of physiology. Heart and circulatory physiology, Estrogen replacement attenuates stress-induced pressor responses through vasorelaxation via β2-adrenoceptors in peripheral arteries of ovariectomized rats., Shoko Tazumi; Sayo Omoto; Yu Nagatomo; Mariko Kawahara; Naoko Yokota-Nakagi; Mizuho Kawakami; Akira Takamata; Keiko Morimoto, We examined whether chronic estrogen replacement has an inhibitory effect on stress-induced pressor responses via activation of β2-adrenoceptor (AR) in peripheral arteries of ovariectomized rats. Female Wistar rats aged 9 wk were ovariectomized. After 4 wk, pellets containing either 17β-estradiol (E2) or placebo (Pla) were subcutaneously implanted into the rats. After 4 wk of treatment, rats underwent cage-switch stress, and, in a separate experiment, a subset received an infusion of isoproterenol (ISO) with or without pretreatment with the β1-AR blocker atenolol or the β2-AR blocker butoxamine. In addition, the isolated mesenteric artery was used to assess the concentration-related relaxing responses to ISO and the β1- or β2-AR mRNA level. The cage-switch stress-induced pressor response was significantly attenuated in the E2-treated group compared with the Pla-treated group. Pretreatment with atenolol reduced blood pressure responses in both groups. However, butoxamine enhanced the pressor response only in the E2-treated group, resulting in no difference between the two groups. In addition, the intravenous ISO-induced depressor response was significantly enhanced in the E2-treated group compared with the Pla-treated group. Furthermore, the difference in the depressor response was abolished by pretreatment with butoxamine but not by atenolol. In the isolated mesenteric artery, butoxamine caused a rightward shift in ISO-induced concentration-related relaxation in the E2-treated group. The β2-AR mRNA level in the mesenteric artery was higher in the E2-treated group than in the Pla-treated group. These results suggest that estrogen replacement attenuated the stress-induced pressor response probably by suppressing vasoconstriction via activation of β2-ARs in peripheral arteries of ovariectomized rats. NEW & NOTEWORTHY In this study, we show, for the first time, that estrogen replacement has an inhibitory effect on the psychological stress-induced pressor response through vasorelaxation via β2-adrenoceptors, probably due to overexpression of β2-adrenoceptor mRNA, in peripheral arteries of ovariectomized rats., 01 Feb. 2018, 314, 2, H213-H223, Scientific journal, True
  • Refereed, Frontiers in Endocrinology, Frontiers Media SA, S-equol Exerts Estradiol-Like Anorectic Action with Minimal Stimulation of Estrogen Receptor-α in Ovariectomized Rats, Yuri Nishimura; Kaori Mabuchi; Azusa Takano; Yayoi Hara; Hiroko Negishi; Keiko Morimoto; Tomomi Ueno; Shigeto Uchiyama; Akira Takamata, 19 Oct. 2017, 8, Scientific journal, True
  • Not Refereed, 実験医学, 摂食調節における性差と性ホルモンの役割, 鷹股 亮; 鷹股亮; 森本恵子, 2017, 35, 6, 945, 950
  • Refereed, Jpn J Biometeor, 日本生気象学会, Body fluid regulation and female reproductive steroids, TAKAMATA Akira, 2017, 54, 2, 57, 64
  • Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Effects of estrogen replacement on stress-induced cardiovascular responses via renin-angiotensin system in ovariectomized rats, Shoko Tazumi; Naoko Yokota; Mizuho Kawakami; Sayo Omoto; Akira Takamata; Keiko Morimoto, Nov. 2016, 311, 5, R898, R905, Scientific journal
  • Refereed, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, SPRINGER, Target intensity and interval walking training in water to enhance physical fitness in middle-aged and older women: a randomised controlled study, Shuichi Handa; Shizue Masuki; Takuya Ohshio; Yoshi-ichiro Kamijo; Akira Takamata; Hiroshi Nose, To determine the target intensity for fast walking during interval walking training (IWT) in water for middle-aged and older people to enhance physical fitness. Thirty-one women [59 +/- 5 (SD) years old] were randomly divided into two groups: IWT on land (LG, N = 15) and in water (WG, N = 16). All subjects were instructed to perform a parts per thousand yen6 sets of fast and slow walking for 3 min each in a day, a parts per thousand yen4 days week(-1), for 8 weeks, at an intensity 35 % higher than the oxygen consumption rate at the gas exchange threshold (O-2GET), with a subjective feeling of 16-18 points of the Borg scale during fast walking in each condition. Before and after IWT, we measured O-2GET, peak aerobic capacity (O-2peak) by graded walking and cycling tests on land and isometric knee extension (F (EXT)) and flexion (F (FLX)) forces. Before IWT, the O-2GET for walking in water was 14 % higher and the heart rate (HR) at a given O-2 was similar to 10 beats min(-1) lower (P=0.001) than on land. During IWT, subjects in both groups performed IWT for similar to 4 days week(-1) (P > 0.9) with a 14 % higher fast walking intensity in WG than in LG (P < 0.05). After IWT, the O-2peak and O-2GET for cycling, F (EXT) and F (FLX) increased more in WG than in LG (all, P < 0.05). Walking in water elevated O-2GET and decreased HR at a given exercise intensity in middle-aged and older women, which enabled them to perform exercise at a higher metabolic rate than on land due to improved subjective feelings, which, for these subjects, resulted in greater gains in physical fitness., Jan. 2016, 116, 1, 203, 215, Scientific journal
  • Not Refereed, 繊維製品消費科学, ヒトをはかる16話(その14)循環機能をはかる, 鷹股 亮, 2015, 56, 8
  • Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER JAPAN KK, Involvement of orexin-A neurons but not melanin-concentrating hormone neurons in the short-term regulation of food intake in rats, Yuri Nishimura; Kaori Mabuchi; Sayumi Taguchi; Saori Ikeda; Eri Aida; Hiroko Negishi; Akira Takamata, May 2014, 64, 3, 203, 211, Scientific journal
  • Not Refereed, 繊維製品消費科学, 一般社団法人 日本繊維製品消費科学会, ヒトをはかる16話(その9)代謝量をはかる, 鷹股 亮, 2014, 55, 10, 722, 723
  • Not Refereed, 繊維製品消費科学, ヒトをはかる16話(その10)酸素消費量をはかる, 鷹股 亮, 2014, 55, 723
  • Refereed, Contrast Media and Molecular Imaging, Mn-citrate and Mn-HIDA: Intermediate-affinity chelates for manganese-enhanced MRI, Yoshiteru Seo; Keitaro Satoh; Hironobu Morita; Akira Takamata; Kazuto Watanabe; Takashi Ogino; Tooru Hasebe; Masataka Murakami, In this study we investigated two manganese chelates in order to improve the image enhancement of manganese-enhanced MRI and decrease the toxicity of free manganese ions. Since both MnCl2 and a low-affinity chelate were associated with a slow continuous decrease of cardiac functions, we investigated intermediate-affinity chelates: manganese N-(2-hydroxyethyl)iminodiacetic acid (Mn-HIDA) and Mn-citrate. The T1 relaxivity values for Mn-citrate (4.4 m m-1 s-1) and Mn-HIDA (3.3 m m-1 s-1) in artificial cerebrospinal fluid (CSF) were almost constant in a concentration range from 0.5 to 5 m m at 37 °C and 4.7 T. In human plasma, the relaxivity values increased when the concentrations of these Mn chelates were decreased, suggesting the presence of free Mn2+ bound with serum albumin. Mn-HIDA and Mn-citrate demonstrated a tendency for better contractility when employed with an isolated perfused frog heart, compared with MnCl2. Only minimal changes were demonstrated after a venous infusion of 100 m m Mn-citrate or Mn-HIDA (8.3 μmol kg-1 min-1) in rats and a constant heart rate, arterial pressure and sympathetic nerve activity were maintained, even after breaking the blood-brain barrier (BBB). Mn-citrate and Mn-HIDA could not cross the intact BBB and appeared in the CSF, and then diffused into the brain parenchyma through the ependymal layer. The responses in the supraoptic nucleus induced by the hypertonic stimulation were detectable. Therefore, Mn-citrate and Mn-HIDA appear to be better choices for maintaining the vital conditions of experimental animals, and they may improve the reproducibility of manganese-enhanced MRI of the small nuclei in the hypothalamus and thalamus. © 2012 John Wiley & Sons, Ltd., Mar. 2013, 8, 2, 140, 146, Scientific journal
  • Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER JAPAN KK, Diffusion of manganese chelates in the rat brain measured by T-1-weighted MRI, Yoshiteru Seo; Akira Takamata; Takashi Ogino; Hironobu Morita; Masataka Murakami, 2013, 63, S137, S137
  • Not Refereed, LISA, 低体温と全身麻酔と代謝,そして腎機能─低温環境で体温維持に働く非ふるえ熱産生 全身麻酔は褐色脂肪組織などの熱産生を阻害する., 鷹股 亮, 2012, 19, 18, 23
  • Not Refereed, 月刊食生活, 健康と水, 鷹股 亮, 2012, 106
  • Refereed, J Phys Fitness Sports Med, The Japanese Society of Physical Fitness and Sports Medicine, Modification of thermoregulatory response to heat stress by body fluid regulation., TAKAMATA Akira, The thermoregulatory system interacts vitally with the body fluid regulatory system. Thermoregulatory response during heat stress, such as sweating and cutaneous vasodilation, stimulates body fluid regulatory response by elevating plasma osmolality and reducing central blood volume. Isotonic hypovolemia, or baroreceptor unloading, and plasma hyperosmolality, in turn, inhibit thermoregulatory response to heat stress, suggesting that body fluid regulation is given priority over thermoregulation. On the other hand, osmoregulatory vasopressin secretion and thirst are augmented by elevated body core temperature. Heat acclimation enhances thermoregulatory response to heat stress. Adaptation of the body fluid regulatory system, such as increased plasma volume and reduced osmotic inhibition of thermoregulatory response, is possibly involved in the mechanism for the enhancement of thermoregulatory response to heat stress by heat acclimation. In this review, we discuss the interaction between body fluid regulation, especially osmoregulation, and thermoregulation mainly in humans., 2012, 1, 3, 479, 489
  • Refereed, 発汗学, 温熱発汗に及ぼす体液調節系からの抑制, 鷹股 亮, 2012, 19, 2, 56, 59, Scientific journal
  • Not Refereed, 体育の科学, 摂食/体重コントロールと性ホルモン, 鷹股 亮, 2012, 62, 12, 942, 945
  • Refereed, BRITISH JOURNAL OF NUTRITION, CAMBRIDGE UNIV PRESS, Chronic oestrogen replacement in ovariectomised rats attenuates food intake and augments c-Fos expression in the suprachiasmatic nucleus specifically during the light phase, Akira Takamata; Kayo Torii; Kana Miyake; Keiko Morimoto, Oct. 2011, 106, 8, 1283, 1289, Scientific journal
  • Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, Lateral diffusion of manganese in the rat brain determined by T-1 relaxation time measured by H-1 MRI, Yoshiteru Seo; Akira Takamata; Takashi Ogino; Hironobu Morita; Masataka Murakami, In order to optimize manganese ion-enhanced MRI in thalamic and hypothalamic nuclei, we analyzed the diffusion of manganese in the brain followed by the intra-cerebroventricular application of manganese-bicine (Mn-bicine). T-1-weighted MRI intensities, with 9-pixel ROIs in the hypothalamus perpendicular to the third ventricle, were measured during continuous infusion of Mn-bicine solution in the lateral cerebroventricle. Using a relationship between the image intensity of T-1-weighted MRI and T-1 relaxation time, the image intensity was converted into the concentration of manganese. Assuming a simple diffusion process, the apparent diffusion coefficient (D-ap) of manganese (4.2 x 10(-5) mm(2) s(-1)) is much lower than that of water (6 x 10(-4) mm(2) s(-1)), and the D-ap tended to decrease when the distance from the third ventricle increased. These results suggest (1) the Mn2+ ion is trapped by neural cells during diffusion and (2) the manganese efflux is discharged from the brain via veins., May 2011, 61, 3, 259, 266, Scientific journal
  • Refereed, MAGNETIC RESONANCE IN MEDICINE, WILEY-BLACKWELL, Mn-bicine: A Low Affinity Chelate for Manganese Ion Enhanced MRI, Yoshiteru Seo; Keitaro Satoh; Kazuto Watanabe; Hironobu Morita; Akira Takamata; Takashi Ogino; Masataka Murakami, The toxicity of free Mn(2+) is a bottleneck for the in vivo application of manganese ion enhanced MRI. To reduce free Mn(2+) concentration ([Mn(2+)]), a low affinity chelate reagent: N,N-bis(2-hydroxyethyl)glycine (bicine) was used. Considering the conditional association constant of Mn-bicine at pH 7.4 (10(2.9) M(-1)), (i) a 100 mM Mn-bicine solution should contain about 10 mM of free manganese ion, but (ii) free manganese will make up 3/4 of the final plasma concentration (0.5 mM) with an intravenous infusion of 100 mM Mn-bicine. The T(1) relaxivity of Mn-bicine in a 5 mM Mn-bicine solution was estimated as 5 mM(-1) sec(-1) at 24 degrees C, 7 T in a pH range of 6.8-7.5. Mn-bicine demonstrated a tendency for better contractility when employed with an isolated perfused frog heart, compared with MnCl(2). A venous infusion of 100 mM Mn-bicine (8.3 mu mol kg(-1) min(-1)) showed a minimal decrease and maintained a constant heart rate level and arterial pressure in rats, while rats infused with 100 mM of MnCl(2) showed a significant suppression of the hemodynamic functions. Thus, Mn-bicine appears to be a better choice for maintaining the vital conditions of experimental animals, and may improve the reproducibility of manganese ion enhanced MRI. Magn Reson Med 65:1005-1012, 2011. (C) 2010 Wiley-Liss, Inc., Apr. 2011, 65, 4, 1005, 1012, Scientific journal
  • Refereed, JOURNAL of the JAPAN RESEARCH ASSOCIATION for TEXTILE END-USES, The Japan Research Association for Textile End-Uses, Gravity/sexual cycle, body fluid, circulation and thermoregulatory function, 鷹股 亮; 鷹股 亮, 2011, 52, 1, 32, 36, Scientific journal
  • Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Plasma hyperosmolality elevates the internal temperature threshold for active thermoregulatory vasodilation during heat stress in humans, Manabu Shibasaki; Ken Aoki; Keiko Morimoto; John M. Johnson; Akira Takamata, Shibasaki M, Aoki K, Morimoto K, Johnson JM, Takamata A. Plasma hyperosmolality elevates the internal temperature threshold for active thermoregulatory vasodilation during heat stress in humans. Am J Physiol Regul Integr Comp Physiol 297: R1706-R1712, 2009. First published October 7, 2009; doi:10.1152/ajpregu.00242.2009.Plasma hyperosmolality delays the response in skin blood flow to heat stress by elevating the internal temperature threshold for cutaneous vasodilation. This elevation could be because of a delayed onset of cutaneous active vasodilation and/or to persistent cutaneous active vasoconstriction. Seven healthy men were infused with either hypertonic (3% NaCl) or isotonic (0.9% NaCl) saline and passively heated by immersing their lower legs in 42 C water for 60 min (room temperature, 28 C; relative humidity, 40%). Skin blood flow was monitored via laser-Doppler flowmetry at sites pretreated with bretylium tosylate (BT) to block sympathetic vasoconstriction selectively and at adjacent control sites. Plasma osmolality was increased by similar to 13 mosmol/kgH(2)O following hypertonic saline infusion and was unchanged following isotonic saline infusion. The esophageal temperature (T(es)) threshold for cutaneous vasodilation at untreated sites was significantly elevated in the hyperosmotic state (37.73 +/- 0.11 degrees C) relative to the isosmotic state (36.63 +/- 0.12 degrees C, P < 0.001). A similar elevation of the Tes threshold for cutaneous vasodilation was observed between osmotic conditions at the BT-treated sites (37.74 +/- 0.18 vs. 36.67 +/- 0.07 degrees C, P < 0.001) as well as sweating. These results suggest that the hyperosmotically induced elevation of the internal temperature threshold for cutaneous vasodilation is due primarily to an elevation in the internal temperature threshold for the onset of active vasodilation, and not to an enhancement of vasoconstrictor activity., Dec. 2009, 297, 6, R1706, R1712, Scientific journal
  • Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Involvement of central angiotensin II type 1 receptors in LPS-induced systemic vasopressin release and blood pressure regulation in rats, Fumihiro Shimizu; Toshihiro Kasai; Akira Takamata, Shimizu F, Kasai T, Takamata A. Involvement of central angiotensin II type 1 receptors in LPS-induced systemic vasopressin release and blood pressure regulation in rats. J Appl Physiol 106: 1943-1948, 2009. First published April 9, 2009; doi:10.1152/japplphysiol.90516.2008.-The purpose of this study was to evaluate the involvement of central angiotensin II (ANG II) and ANG II type 1 (AT(1)) receptors in systemic release of arginine vasopressin (AVP) and blood pressure regulation during endotoxemia. LPS (150 mu g/kg) was injected intravenously 30 min after intracerebroventricular (icv) losartan (50 mu g), an AT(1) receptor antagonist, or subcutaneous (sc) captopril (50 mg/kg), an angiotensin-converting enzyme inhibitor. Rats with icv and sc saline injections served as control. LPS administration increased plasma AVP concentration from 2.1 +/- 0.2 to 15.2 +/- 2.5 pg/ml (60 min after LPS injection) without significant changes in plasma osmolality or hematocrit. LPS-induced AVP secretion was significantly attenuated by pretreatment with icv losartan (2.3 +/- 0.5 to 3.7 +/- 0.5 pg/ml) but was not attenuated after peripheral captopril treatment (2.2 +/- 0.6 to 17.6 +/- 4.2 pg/ml). LPS administration significantly decreased systolic blood pressure (SBP) by 22.7 +/- 5.4 mmHg after intravenous LPS injection in icv losartan-treated rats, while SBP remained unchanged in vehicle-treated or sc captopril-treated rats by intravenous LPS. These results indicate that central AT(1) receptors, not responsive to peripheral ANG II, play an important role in systemic AVP secretion and maintenance of blood pressure during endotoxemia., Jun. 2009, 106, 6, 1943, 1948, Scientific journal
  • Not Refereed, 臨床スポーツ医学 臨時増刊号 スポーツ栄養・食事ガイド, 運動・スポーツにおける体温調節と水分摂取, 鷹股 亮; 鷹股 亮, 2009, 26, 60, 66
  • Not Refereed, 臨床スポーツ医学 臨時増刊号 スポーツ栄養・食事ガイド, 女性, 鷹股 亮; 鷹股 亮, 2009, 26, 264, 271
  • Not Refereed, LIFE SCIENCES, PERGAMON-ELSEVIER SCIENCE LTD, Mental stress induces sustained elevation of blood pressure and lipid peroxidation in postmenopausal women, Keiko Morimoto; Mayuko Morikawa; Hiroko Kimura; Nobuko Ishii; Akira Takamata; Yasuko Hara; Masami Uji; Ken-ichi Yoshida, Mental stress is thought to underlie cardiovascular events, but there is information on oxidative stress induced by mental stress in association with cardiovascular responses in women. Using a sensitive assay for plasma 4-hydroxy-2-nonenal (HNE), as a marker for oxidative stress, we addressed the relation between pressor responses and oxidative stress induced by mental or physical stress in premenopausal and postmenopausal women. Healthy subjects (7 postmenopausal and 8 premenopausal women, in early and late follicular phases) were subjected to mental and physical stress evoked by a Color Word Test (CWT) and isometric handgrip, respectively. The CWT induced a rapid elevation of diastolic blood pressure (DBP), at a higher level in the postmenopausal than in the premenopausal women (p<0.01), and this higher DBP was sustained during the CWT and recovery (p<0.01). The CWT induced a significant elevation in plasma noradrenaline in premenopausal women in the early follicular phase and in postmenopausal women (p<0.05). Plasma nitric oxide metabolites were higher in postmenopausal than in the premenopausal women in the late follicular phase (p<0.05), but did not change during exposure to the two types of stress in either group. Plasma HNE was increased during recovery from the CWT, but not the handgrip, in postmenopausal women (2.4 times, p<0.05). There was a significant difference in the time course of the CWT-induced HNE response between the postmenopausal and premenopausal women (p<0.05). These findings suggest that mental, but not physical, stress causes sustained diastolic blood pressure elevation in postmenopausal women, accompanied by heightened oxidative stress. (C) 2007 Elsevier Inc. All rights reserved., Jan. 2008, 82, 1-2, 99, 107, Scientific journal
  • Not Refereed, Stress, Neurotransmitters, and Hormones: Neuroendocrine and Genetic Mechanisms, BLACKWELL PUBLISHING, Effects of Estrogen on Stress-induced Activation of Peptide Neurons in PVN of Ovariectomized Rats, Yasuko Hara; Tomomi Kohno; Akira Takamata; Takashi Ueyama; Keiko Morimoto, Estrogen has been implicated in brain function related to stress responses. We investigated whether estrogen affects psychological stress-induced activation of peptide-containing or nitric oxide-producing neurons in the paraventricular hypothalamic nucleus (PVN) in ovariectomized (OVX) rats, both placebo-treated (OVX + Pla) and estrogen-treated (OVX + E2) by comparison of c-Fos expression using immunohistochemistry. Cage-switch stress increased activation in oxytocinergic neurons in the parvocellular PVN (pPVN) in OVX + Pla, but not in that of OVX + E2, rats. Moreover, the stress-induced activation in NADPH-diaphorase-positive neurons in the pPVN was larger in the OVX + E2 than in the OVX + Pla group. These findings suggest that estrogen attenuates the activation of oxytocinergic neurons in the pPVN, at least in part via nitric oxide., 2008, 1148, 99, 105, Scientific journal
  • Not Refereed, STRESS, NEUROTRANSMITTERS, AND HORMONES: NEUROENDOCRINE AND GENETIC MECHANISMS, BLACKWELL PUBLISHING, Estrogen Replacement Suppresses Pressor Response and Oxidative Stress Induced by Cage-switch Stress in Ovariectomized Rats, Keiko Morimoto; Masami Uji; Takashi Ueyama; Hiroko Kimura; Tomomi Kohno; Akira Takamata; Shigenobu Yano; Ken-Ichi Yoshida, We examined the suppressive effects of estradiol on psychological stress-induced cardiovascular responses and oxidative stress in ovariectomized rats, both placebo-treated (OVX+Pla) and estrogen-treated (OVX+E2). The elevations in blood pressure and heart rate induced by cage-switch stress were attenuated in the OVX+E2 as compared with the OVX+Pla group. N(G)-nitro-L-arginine methyl ester, administered via drinking water, reduced the difference in these responses. Furthermore, this stress increased plasma nitrotyrosine and decreased plasma nitric oxide (NO) metabolites only in the OVX+Pla group. We demonstrated that estrogen replacement suppresses cardiovascular responses to psychological stress, at least in part by improving NO bioavailability in ovariectomized rats., 2008, 1148, 213, 218, Scientific journal
  • Not Refereed, JAPANESE JOURNAL OF BIOMETEOROLOGY, Japanese Society of Biometeorology, Effect of calf heating and muscle injury on calf venous compliance and capillary filtration coefficient, FUKUI Yoko; YAMAMOTO Kana; TAKAMATA Akira, To gain better insights into the hydrostatic effect on blood pooling and edema formation in the lower limbs, we examined the effect of local calf heating and muscle injury on venous compliance and capillary filtration coefficient (Kf). Ten young female subjects participated in this study. After 60 min supine rest, a cuff on the thigh was inflated to 50 mmHg in 10 mmHg steps every 7-minute, and we measured calf volume and cardiovascular variables. We conducted the same experiment with local calf heating. After the first-day experiment, subjects performed calf raise exercise (4* 100 times). All subjects claimed muscle soreness on the next day, and we conducted the same experiment as the first day experiment on the second day. We determined the venous compliance and Kf from the relationships between blood volume change (first phase of calf volume change) and cuff pressure, and between transcapillary fluid movement (second phase of calf volume change) and cuff pressure, respectively. Venous compliance was not influenced by calf heating or muscle injury. Kf on the second day was higher than that on the first day, and Kf was increased with calf heating on the second day. These suggest that muscle injury increases Kf, and local calf heating enhances the effect of muscle injury on Kf.
    , 2007, 44: 13-39, 1, 13, 39
  • Not Refereed, 繊維製品消費科学, 一般社団法人 日本繊維製品消費科学会, 衣服を用いた運動時の静脈還流量維持と体温・循環反応ーその生理学的背景, 鷹股 亮; 鷹股亮, 2006, 47, 12, 712, 718
  • Not Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Acute hypoosmolality attenuates the suppression of cutaneous vasodilation with increased exercise intensity, H Mitono; H Endoh; K Okazaki; T Ichinose; S Masuki; A Takamata; H Nose, We examined the hypothesis that elevation of the body core temperature threshold for forearm skin vasodilation (THFVC) with increased exercise intensity is partially caused by concomitantly increased plasma osmolality Eight young male subjects, wearing a body suit perfused with warm water to maintain the mean skin temperature at 34 +/- 1 degrees C (ranges), performed 20-min cycle-ergometer exercise at 30% peak aerobic power ((V) over dot o(2 peak)) under isoosmotic conditions (C), and at 65% (V) over dot o(2 pea)k under isoosmotic (HEXIOS) and hypoosmotic (HEXLos) conditions. In HEXLos, hypoosmolality was attained by hypotonic saline infusion with DDAVP, a V-2 agonist, before exercise. P-osmol (mosmol/kgH(2)O) increased after the start of exercise in both H-EX trials (P < 0.01) but not in C. The average P-osmol at 5 and 10 min in HEXIos was higher than in C (P < 0.01), whereas that in HEXLos was lower than in HEXIos (P < 0.01). The change in THFVC was proportional to that in P-osmol in every subject for three trials. The change in THFVC per unit change in P-osmol (Delta THFVC/Delta P-osmol, degrees C center dot mosmol(-1)center dot kgH(2)O(-1)) was 0.064 +/- 0.012 when exercise intensity increased from C to HEXIOS, similar to 0.086 +/- 0.020 when P-osmol decreased from HEXIOS to HEXLOS (P > 0.1). Moreover, there were no significant differences in plasma volume, heart rate, mean arterial pressure, and plasma lactate concentration around THFVC between HEXIOS and HEXLOS (P > 0.1). Thus the increase in THFVC due to increased exercise intensity was at least partially explained by the concomitantly increased P-osmol., Sep. 2005, 99, 3, 902, 908, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Plasma hyperosmolality augments peripheral vascular response to baroreceptor unloading during heat stress, T Ito; T Itoh; T Hayano; K Yamauchi; A Takamata, The aim of this study was to elucidate the interactive effect of central hypovolemia and plasma hyperosmolality on regulation of peripheral vascular response and AVP secretion during heat stress. Seven male subjects were infused with either isotonic (0.9%; NOSM) or hypertonic (3.0%; HOSM) NaCl solution and then heated by perfusing 42 degrees C (heat stress; HT) or 34.5 degrees C water (normothermia; NT) through water perfusion suits. Sixty minutes later, subjects were exposed to progressive lower body negative pressure (LBNP) to -40 mmHg. Plasma osmolality (P-osmol) increased by similar to 11 mosmol/kgH(2)O in HOSM conditions. The increase in esophageal temperature before LBNP was much larger in HT-HOSM (0.90 +/- 0.09 degrees C) than in HT-NOSM (0.30 +/- 0.07 degrees C) (P < 0.01) because of osmotic inhibition of thermoregulation. During LBNP, mean arterial pressure was well maintained, and changes in thoracic impedance and stroke volume were similar in all conditions. Forearm vascular conductance (FVC) before application of LBNP was higher in HT than in NT conditions (P < 0.001) and was not influenced by Posmol within the thermal conditions. The reduction in FVC at -40 mmHg in HT-HOSM (-9.99 +/- 0.96 units; 58.8 +/- 4.1%) was significantly larger than in HT-NOSM (-6.02 +/- 1.23 units; 44.7 +/- 8.1%) (P < 0.05), whereas the FVC response was not different between NT-NOSM and NT-HOSM. Plasma AVP response to LBNP did not interact with P-osmol in either NT or HT conditions. These data indicate that there apparently exists an interactive effect of P-osmol and central hypovolemia on the peripheral vascular response during heat stress, or peripheral vasodilated conditions, but not in normothermia., Aug. 2005, 289, 2, R432, R440, Scientific journal
  • Not Refereed, INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE, ASSOC RESEARCH VISION OPHTHALMOLOGY INC, Effect of environmental conditions on tear dynamics in soft contact lens wearers, K Maruyama; N Yokoi; A Takamata; S Kinoshita, PURPOSE. Dry eye symptoms are often associated with soft contact lens (SCL) wear and may be affected by environmental conditions. This study was conducted to determine the effects of temperature and humidity on the tear film in SCL wearers. METHODS. All 11 enrolled subjects were males (mean age, 23.5 +/- 5.2 [SD] years), and all wore SCL daily. They were exposed in different sessions to four different conditions in an environmental chamber with the air temperature (AT) and relative humidity (RH) set at 5degreesC/10% (AT/RH), 15degreesC/20%, 25degreesC/40%, or 35degreesC/50%. Two different types of hydrogel SCL (SCL-a and SCL-b; water content 72.0% and 37.5%, respectively) were used. The meniscus tear volume was determined on a video meniscometer by measuring the tear meniscus radius (TMR) with and without SCL. The tear interference patterns on the contact lens (TIPCL) were classified into five grades (the higher the grade, the thinner the film). Using a video interferometer, the non-invasive tear film breakup time (NIBUT) was recorded with and without SCLs; ocular dryness was also scored with and without SCLs. RESULTS. Under the environmental conditions examined, there were no significant differences in the TMR without or with SCL, regardless of their type. As AT and RH decreased, there was a significant increase in the TIPCL grade (CL-a: P = 0.042; CL-b: P = 0.002), a significant decrease in NIBUT (CL-a: P = 0.004; CL-b: P = 0.001), and a significant increase in the dryness score (without SCL P = 0.023; with CL-a P = 0.009; with CL-b P = 0.003). The dryness scores were higher with CL-a than CL-b (P = 0.011 at 15degreesC/20%). Under identical experimental conditions, we observed no significant change in NIBUT in the absence of an SCL. CONCLUSIONS. AT and RH apparently had no effect on the tear volume in the presence of SCLs. As AT and RH decreased, the tear film on the SCL became thinner, NIBUT became shorter, and dryness increased. Dryness was more pronounced in eyes with SCL of the higher water content., Aug. 2004, 45, 8, 2563, 2568, Scientific journal
  • Not Refereed, AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL, ELSEVIER SCIENCE BV, Sequence of forebrain activation induced by intraventricular injection of hypertonic NaCl detected by Mn2+ contrasted T-1-weighted MRI, H Morita; T Ogino; N Fujiki; K Tanaka; TM Gotoh; Y Seo; A Takamata; S Nakamura; M Murakami, In order to define the sequence of forebrain activation involved in osmoregulation, central activation in response to intracerebroventricular injection of NaCl solution (10 mul of 0.15, 0.5, or 1.5 M) was detected using manganese-contrasted magnetic resonance imaging (MRI) in anesthetized rats. Changes in renal sympathetic nerve activity (RNA) were also measured, and the time courses of forebrain activation and RNA changes compared. NaCl injection resulted in rapid activation of the subfornical organ (SFO), organum vasculosum lamina terminalis (OVLT), and periventricular regions and the lateral hypothalamic area (LHA), then of the paraventricular hypothalamic nucleus (PVN) and supraoptic nucleus (SON). The delay in activation in the PVN and SON showed a wide variation from 0 to 5.78 min, and the average delay in the PVN (2.88 +/- 0.34 min) and SON (2.90 +/- 0.39 min) was significantly greater than that in the SFO (0.40 +/- 0.10 min) and OVLT (0.74 +/- 0.13 min). NaCl (1.5 M) injection elicited a rapid, large increase in RNA, which consisted of two components, an early rapid increase at 99 s after injection (160 +/- 27%) and a slower increase at 9 min after injection (209 +/- 34%). These results suggest that the PVN and SON are activated not only by the afferent input from the SFO and OVLT but also by diffusion of the hypertonic stimulus to these regions and probably by their intrinsic osmosensitivity. The PVN might be responsible for the second slower component of the RNA response, but cannot be responsible for the first component. (C) 2004 Elsevier B.V. All rights reserved., Jun. 2004, 113, 1-2, 43, 54, Scientific journal
  • Not Refereed, ANESTHESIOLOGY, LIPPINCOTT WILLIAMS & WILKINS, Effect of amino acid infusion on central thermoregulatory control in humans, Y Nakajima; A Takamata; T Matsukawa; DI Sessler; Y Kitamura; H Ueno; Y Tanaka; T Mizobe, Background. Administration of protein or amino acids enhances thermogenesis, presumably by stimulating oxidative metabolism. However, hyperthermia results even when thermoregulatory responses are intact, suggesting that amino acids also alter central thermoregulatory control. Therefore, the authors tested the hypothesis that amino acid infusion increases the thermoregulatory set point. Methods. Nine male volunteers each participated on 4 study days in randomized order: (1) intravenous amino acids infused at 4 kJ(.)kg(-1.)h(-1) for 2.5 h combined with skin-surface warming, (2) amino acid infusion combined with cutaneous cooling, (3) saline infusion combined with skin-surface warming, and (4) saline infusion combined with cutaneous cooling. Results: Amino acid infusion increased resting core temperature by 0.3 +/- 0.1 degreesC (mean +/- SD) and oxygen consumption by 18 +/- 12%. Furthermore, amino acid infusion increased the calculated core temperature threshold (triggering core temperature at a designated mean skin temperature of 34 degreesC) for active cutaneous vasodilation by 0.3 +/- 0.3 degreesC, for sweating by 0.2 +/- 0.2 degreesC, for thermoregulatory vasoconstriction by 0.3 +/- 0.3 degreesC, and for thermogenesis by 0.4 +/- 0.5 degreesC. Amino acid infusion did not alter the incremental response intensity (i.e., gain) of thermoregulatory defenses. Conclusions: Amino acid infusion increased the metabolic rate and the resting core temperature. However, amino acids also produced a synchronous increase in all major autonomic thermoregulatory defense thresholds; the increase in core temperature was identical to the set point increase, even in a cold environment with amble potential to dissipate heat. in subjects with intact thermoregulatory defenses, amino acid-induced hyperthermia seems to result from an increased set point rather than increased metabolic rate per se., Mar. 2004, 100, 3, 634, 639, Scientific journal
  • Not Refereed, 体育の科学, 運動・ホルモンと水分代謝, 鷹股 亮; 鷹股亮, 2004, 54, 43, 47
  • Not Refereed, Japanese journal of biometeorology, Japanese Society of Biometeorology, Prevention of heat stroke by ingesting fluid : its physiological mechanisms, TAKAMATA Akira, Thermoregulatory sweating decreases extracellular fluid (ECF) volume and increases ECF osmaolality. In addition, increased skin blood flow during heat stress decreases venous return to the heart, resulting in cardiopulmonary baroreceptor unloading. Plasma hyperosmolality inhibits both thermally-induced cutaneous vasodilaiton and sweating by elevating the body core temperature (Tc) thresholds for these responses. The decreased ECF volume, or cardiopulmonary baroreceptor unloading, during heat stress inhibits thermoregulatory cutaneous vasodilation and also increases heart rate via cardiopulmonary baroreceptor reflexes/. Therefore, fluid ingestion is necessary to maintain thermoregulatory and cardiovascular function during heat stress. It is necessary to replace sodium for full recovery from thermal dehydration. The optimal sodium concentration in beverage might be dependent on the level of heat acclimation, because heat acclimation reduces sweat sodium concentration. Fluid ingestion before exercise is more beneficial to maintain thermoregulatory and cardiovascular function during exercise in a hot environment than fluid ingestion during exercise. Thus, timing of fluid ingestion influences thermoregulation and cardiovascular regulation during exercise.
    , 2004, 41, 1, 55, 59
  • Not Refereed, ACTA ANAESTHESIOLOGICA SCANDINAVICA, BLACKWELL MUNKSGAARD, The vasoconstriction threshold is increased in obese patients during general anaesthesia, T Kasai; M Hirose; T Matsukawa; A Takamata; Y Tanaka, Background: In anaesthetized patients, body temperature decreases often, but overweight patients become less hypothermic. Obesity in itself protects body heat, and thermoregulatory reflexes may maintain normothermia in obese patients. We tested the hypothesis that even slight obesity increases the vasoconstriction threshold. Methods: Twenty male patients aged 30-65 years scheduled for open abdominal surgery were allocated to two groups: body fat greater than or equal to25% (obese group, n = 10), or <25% (normal weight group, n = 10). Anaesthesia was maintained with 0.4% isoflurane and opioid. The thermoregulatory vasoconstriction threshold was defined by the tympanic membrane temperature at which the skin temperature gradient equalled 0degreesC. Plasma adrenaline, noradrenaline and leptin were measured. Results: Age, height, heart rate and blood pressure did not differ between the two groups of patients. In the obese group the vasoconstriction threshold was higher than that in the normal weight group: 36.0 +/- 0.1 vs. 35.5 +/- 0.2degreesC. Consequently, after 4 h of anaesthesia, the core temperature was highest in the obese patients: 36.4 +/- 0.1 vs. 35.5 +/- 0.2degreesC. Conclusions: These results suggest that core temperature is maintained in obese patients because their vasoconstriction threshold to a low environmental temperature is high., May 2003, 47, 5, 588, 592, Scientific journal
  • Not Refereed, SHOCK, LIPPINCOTT WILLIAMS & WILKINS, Reduced blood-to-tissue albumin movement after plasmapheresis, AM Stahl; CM Gillen; A Takamata; ER Nadel; GW Mack, We tested the hypothesis that a decrease in the blood-to-tissue movement of albumin contributes to the recovery of plasma albumin and plasma volume after acute plasma protein depletion (plasmapheresis). Awake and unrestrained male Sprague-Dawley rats (220-320 g) fitted with jugular catheters were plasmapheresed, and plasma volume, plasma albumin, and total plasma protein content were measured at 1, 5, 24, and 48 h postplasmapheresis. Plasma volume recovered to baseline within 1 h (4.6 +/- 0.42 vs. 4.7 +/- 0.46 mL/100 g body weight (bw), remained at baseline from 5 h to 24 h but increased to 5.5 +/- 0.57 mL/100 g bw at 48 h (P < 0.05). Plasma albumin and total protein content recovered rapidly but remained below baseline levels at 1 h (10.05 +/- 0.98 vs. 12.33 +/- 1.29 and 19.75 +/- 1.75 vs. 24.73 +/- 2.56 mg/100 g bw, respectively). Plasma protein content returned to baseline by 5 h of recovery. Tissue uptake of I-125-labeled albumin decreased in the heart, skin, skeletal muscle, and small intestines of plasmapheresed rats (P < 0.05). These data support the hypothesis that a reduction in albumin efflux from the vascular space contributes to the recovery of plasma albumin and total protein content during plasma volume recovery and eventual expansion after plasmapheresis., May 2003, 19, 5, 440, 447, Scientific journal
  • Not Refereed, ACTA ANAESTHESIOLOGICA SCANDINAVICA, BLACKWELL MUNKSGAARD, Preoperative blood pressure and catecholamines related to hypothermia during general anesthesia, T Kasai; M Hirose; T Matsukawa; A Takamata; K Yaegashi; Y Tanaka, Background: We previously demonstrated that preoperative blood pressure values affect intraoperative hypothermia during general anesthesia. We hypothesized that increased catecholamine secretion could be responsible for the relationship between preoperative blood pressure and hypothermia. Methods: To evaluate the effect of preoperative systolic blood pressure (SBP) and plasma catecholamine levels on core temperature during general anesthesia, 40 male patients who were scheduled for open abdominal surgery were allocated to two groups: those whose preoperative SBP was 140 mmHg or greater (high SBP group, n = 20), and those whose SBP was less than 140 mmHg (normal SBP group, n = 20). Anesthesia was maintained with 0.4% isoflurane and opioids. Results: The average age, height, and weight of the patients in the two groups did not differ. Preoperative SBP, mean blood pressure, diastolic blood pressure and heart rate in the high SBP group were significantly higher than those in the normal SBP group. Plasma norepinephrine concentrations in the high SBP group were significantly greater than those in the normal SBP group before and 1 h after the induction of anesthesia. Tympanic membrane temperatures in the normal SBP group started to decline further just after the induction of anesthesia, more so than that in the high SBP group. The vasoconstriction threshold in the normal SBP group was significantly lower than that in the high SBP group. Conclusion: These results suggest that the higher levels of preoperative catecholamine secretion contributed to the lesser degree of intraoperative hypothermia observed in the high SBP group., Feb. 2003, 47, 2, 208, 212, Scientific journal
  • Not Refereed, JOURNAL OF PHYSIOLOGY-LONDON, CAMBRIDGE UNIV PRESS, Water permeability of capillaries in the subfornical organ of rats determined by Gd-DTPA(2-) enhanced H-1 magnetic resonance imaging, Y Seo; A Takamata; T Ogino; H Morita; S Nakamura; M Murakami, The water permeability of capillaries in the subfornical organ (SFO) of rat was measured by a H-1 nuclear magnetic resonance method in combination with a venous injection of a relaxation reagent, gadolinium-diethylene triamine-N,N,N,N",N"-pentaacetic acid (Gd-DTPA(2-)), which could not pass through the blood-brain barrier (BBB). Judging from results of Gd-DTPA(2-) dose dependency in the intact brain and the BBB-permeabilized brain, Gd-DTPA(2-) could not have leaked out from the capillaries in the cortex, thalamus or SFO, but it could have been extravasated in the posterior lobe of the pituitary gland. The longitudinal (T,) relaxation time of water in the SFO region was measured by inversion-recovery magnetic resonance imaging at 4.7 T. The T-1 relaxation rates (1/T-1) before and after Gd-DTPA(2-) infusion were 0.70 +/- 0.02 s(-1) (mean +/- S.E.M., n = 9) and 1.53 +/- 0.11 s(-1) (n = 9), respectively. The rate constant for water influx to the capillaries was estimated to be 0.84 +/- 0.11 s(-1) (n = 9) which corresponds with a diffusive membrane permeability (P-d) of 3.7 x 10(-3) cm s(-1). Compared with values found in the literature available on this subject, this Pd value for the capillaries in the SFO was the same order of magnitude as that for transmembrane permeability of water for the vasa recta, and it may be 10-100 times larger than that of the blood-brain barrier in the cortex. Areas of the cortex and thalamus showed minimal changes in the T-1 relaxation rate (ca 0.09 s(-1)), but these values were not statistically significant and they corresponded to P-d values much smaller than those found in the SFO. From these results, we conclude that the capillaries in the SFO have one of the highest water permeability values among all of the capillaries in the brain. It is also suggested that this magnetic resonance imaging, based on T-1 relaxation rate, is a useful method to detect local water permeability in situ., Nov. 2002, 545, 1, 217, 228, Scientific journal
  • Not Refereed, ANESTHESIA AND ANALGESIA, LIPPINCOTT WILLIAMS & WILKINS, Preoperative risk factors of intraoperative hypothermia in major surgery under general anesthesia, T Kasai; M Hirose; K Yaegashi; T Matsukawa; A Takamata; Y Tanaka, Preoperative factors, such as age and body habitus, affect intraoperative hypothermia during general anesthesia. In a preliminary study, we developed a logistic model to retrospectively evaluate predictors of intraoperative hypothermia in patients who received major surgery. The following factors were selected to develop the model: Z = -15.014 + 0.097 x (Age) + 0.263 x (Height) - 0.323 x (Weight) - 0.055 x (Preoperative systolic blood pressure) - 0.121 X (Preoperative heart rate). By using this model, the probability of hypothermia can be estimated by applying the following formula: Probability = 1/(1 + e(-z)). If an estimated probability of hypothermia was >0.5, the sensibility of prediction was 81.5% and the specificity was 83%. In the second study, the model was applied prospectively to other patients, and the validity of the logistic model was evaluated. The core temperature showed a significant decrease in patients with a probability >0.7, who were predicted to be hypothermic, and their thermoregulatory vasoconstriction threshold also showed a significant decrease, compared with the patients with a probability less than or equal to0.3, who were predicted to be normothermic. We concluded that intraoperative hypothermia could be predicted from preoperative characteristics such as age, height, weight, systolic blood pressure, and heart rate., Nov. 2002, 95, 5, 1381, 1383, Scientific journal
  • Not Refereed, NEUROSCIENCE LETTERS, ELSEVIER SCI IRELAND LTD, Detection of hypothalamic activation by manganese ion contrasted T-1-weighted magnetic resonance imaging in rats, H Morita; T Ogino; Y Seo; N Fujiki; K Tanaka; A Takamata; S Nakamura; M Murakami, To examine the usefulness of Mn2+ contrasted magnetic resonance imaging (MRI) in hypothalamic imaging, images obtained using T-1-weighted MRI were compared with Fos expression, which is known to increase after activation of voltage-dependent Ca2+ channels. Intravenous infusion of MnCl2 elicited a rapid increase in the T-1-weighted MRI signal intensity in the vessels and ventricles, but not in the brain parenchyma, suggesting that Mn2+ did not diffuse freely across the blood-brain barrier. When the blood-brain barrier was broken by right intracarotid arterial injection of 25% D-mannitol, an increased signal intensity was seen in the right brain. Intracarotid arterial injection of hypertonic NaCl elicited rapid and striking increases in signal intensity in the paraventricular hypothalamic nucleus, supraoptic nucleus, and preoptic area, which are thought to be involved in central osmotic regulation. These observations were consistent with the Fos expression results. These results indicate that Mn2+ contrasted MRI is a useful technique for investigating the autonomic center in the hypothalamus. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved., Jun. 2002, 326, 2, 101, 104, Scientific journal
  • Not Refereed, ANESTHESIA AND ANALGESIA, LIPPINCOTT WILLIAMS & WILKINS, Upright posture reduces thermogenesis and augments core hypothermia, Y Nakajima; A Takamata; T Ito; DI Sessler; Y Kitamura; G Shimosato; S Taniguchi; H Matsuyama; Y Tanaka; T Mizobe, We recently reported that baroreceptor-mediated reflexes modulate thermoregulatory vasoconstriction during lower abdominal surgery. Accordingly, we examined the hypothesis that postural differences and the related alterations in baroreceptor loading similarly modulate the thermogenic (i.e., shivering) response to hypothermia in humans. In healthy humans (n = 7), cold saline was infused W (30 mL/kg at 4degreesC) for 30 min to decrease core temperature. Each participant was studied on 2 separate days, once lying supine and once sitting uptight. Tympanic membrane temperature and oxygen consumption were monitored for 40 min after each saline infusion. The decrease in core temperature upon completion of the infusion in the upright posture position was 1.24degreesC +/- 0.07degreesC, which was significantly greater than the 1.02degreesC +/- 0.06degreesC seen in the supine position. The core temperature was reduced by 0.59degreesC +/- 0.07degreesC in the upright position but only by 0.37degreesC +/- 0.05degreesC in the supine position when the increase in oxygen consumption signaling thermogenic shivering occurred. Thus, the threshold temperature for thermogenesis was significantly less in the upright than the supine position. The gain of the thermogenic response did not differ significantly between the positions (363 +/- 69 mL.min(-1).degreesC(-1) for upright and 480 +/- 80 mL . min(-1) . degreesC(-1) for supine). The skin temperature gradient was significantly larger in the upright than in the supine posture, suggesting that the peripheral vasoconstriction was augmented by upright posture. Plasma norepinephrine concentrations increased in response to cold saline infusion under both conditions, but the increase was significantly larger in the upright than in the supine posture. Baroreceptor unloading thus augments the peripheral vasoconstrictor and catecholamine response to core hypothermia but simultaneously reduces thermogenesis, which consequently aggravated the core temperature decrease in the upright posture., Jun. 2002, 94, 6, 1646, 1651, Scientific journal
  • Not Refereed, 綜合臨床, 夏期の作業・運動時における効果的な水分補給, 鷹股 亮, 2002, 51, 2295, 2296
  • Not Refereed, JAPANESE JOURNAL OF PHYSIOLOGY, CENTER ACADEMIC PUBL JAPAN, Role of blood volume in the age-associated decline in peak oxygen uptake in humans, T Ito; A Takamata; K Yaegashi; T Itoh; T Yoshida; T Kawabata; M Kimura; T Morimoto, It has been reported that maximal oxygen uptake ((V) over dot O-2max) is linearly correlated with blood volume (BV) in young people and that there is a reduction in (V) over dot O-2max with aging. To examine the involvement of BV in the reduction of (V) over dot O-2max, we used an incremental cycle ergometer protocol in a semirecumbent position to determine the relationship between peak oxygen uptake ((V) over dot O-2peak) and BV in older subjects (69.1 +/- 1.0 years, n=22), then compared that relationship with that in young subjects (22.3 +/- 0.5 years; n=31). In the present study, (V) over dot O-2peak and BV were significantly lower in the older subjects, compared with those in the young subjects. A linear correlation was demonstrated between the (V) over dot O-2peak and BV in both the older (r=0.705; p<0.001) and the young (r=0.681; p<0.001) subjects within the groups. However, an analysis of covariance with BV as a covariate revealed that (V) over dot O-2peak at a given BV was smaller in the older subjects than in the young subjects (p<0.001), i.e., graphically, the regression line determined for the older subjects showed a downward shift. The decreased peak heart rate as a result of aging (153 +/- 3 beats/min in the older vs. 189 +/- 2 beats/min in the young subjects) contributed partly to this downward shift. These results suggest that the BV is an important determinant factor for (V) over dot O-2peak, especially within an age group, and that the age-associated decline of (V) over dot O-2peak is also, to a relatively larger degree, because of factors other than BV and heart rate., Oct. 2001, 51, 5, 607, 612, Scientific journal
  • Not Refereed, JAPANESE JOURNAL OF PHYSIOLOGY, CENTER ACADEMIC PUBL JAPAN, Effects of pCO(2) on the CSF turnover rate in rats monitored by Gd-DTPA enhanced T-1-weighted magnetic resonance imaging, A Takamata; Y Seo; T Ogino; K Tanaka; N Fujiki; H Morita; M Murakami, The cerebrospinal fluid (CSF) secretion of rat was monitored by longitudinal relaxation time-weighted magnetic resonance imaging (T-1-weighted MRI) in combination with a ventricular injection of a T-1-relaxation reagent: gadolinium-diethylene triamine-N,N,N',N",N"-pentaacetic acid (Gd-DTPA). A cannula was inserted in the left lateral ventricle, and 5 mul of 8.5 mm Gd-DTPA was injected as a CSF marker. Changes in the image intensity of the CSF were measured every 30 s, and the turnover rate of CSF (k) in the left lateral ventricle was obtained from the dilution of Gd-DTPA, based on the assumption of a single compartment model. In the control conditions, k was 0.158 +/- 0.009 min(-1) at an arterial blood CO2 tension (pCO(2)) of 38.6 +/- 2.2 mmHg (n=10), which corresponds to the CSF secretion rate of 3.6 mul min(-1). The k value was decreased (0.078 +/- 0.010 min(-1), n=4) by a carbonic-anhydrase inhibitor (acetazolamide). The turnover rate was decreased by hypocapnia (0.094+/-0.019 min(-1), pCO(2)=24.7 +/- 2.9 mmHg, n=4), and it increased gradually and reached a plateau level as a result of hypercapnia (0.194 +/- 0.011 min(-1), pCO(2)=104.5 +/- 7.1 mmHg, n=10). These results suggested that CO2 upregulates the secretion of CSF in the rat., Oct. 2001, 51, 5, 555, 562, Scientific journal
  • Not Refereed, ACTA ANAESTHESIOLOGICA SCANDINAVICA, MUNKSGAARD INT PUBL LTD, Preoperative blood pressure and intraoperative hypothermia during lower abdominal surgery, T Kasai; M Hirose; T Matsukawa; A Takamata; M Kimura; Y Tanaka, Background: Preoperative factors including age and body habitus affect intraoperative hypothermia during general anesthesia. We hypothesized that preoperative blood pressure also plays a contributory role in the induction of intraoperative hypothermia. Methods: We evaluated the effect of preoperative systolic blood pressure (SBP) on core temperature during lower abdominal surgery under general anesthesia. In 36 female patients under 65 years of age, patients with a preoperative SBP of 140 mmHg or greater upon arrival in the operating theater were assigned to the high SBP group (n=18), while those with SBP below 140 mmHg were assigned to the normal SBP group (n=18). Anesthesia was maintained with isoflurane and nitrous oxide combined with epidural buprenorphine, and routine thermal care was provided intraoperatively. Results: There were no significant differences in age, height or weight between the two groups. Tympanic membrane temperature in the normal SBP group started to decrease significantly from 15 min after induction of anesthesia compared to that in the high SBP group, and continued to decrease further at two hours after induction. Vasoconstriction threshold, determined to be tympanic membrane temperature at the time when a forearm minus finger skin surface gradient exceeded 0 degreesC, was significantly higher in the high SBP group than in the normal SBP group. Conclusion: These results suggest that preoperative SBP has some preventive effect on the decrease in intraoperative core temperature during lower abdominal surgery under general anesthesia., Sep. 2001, 45, 8, 1028, 1031, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Relationship of osmotic inhibition in thermoregulatory responses and sweat sodium concentration in humans, A Takamata; T Yoshida; N Nishida; T Morimoto, Heat acclimatization improves thermoregulatory responses to heat stress and decreases sweat sodium concentration ([Na+](sweat)). The reduced [Na+](sweat) results in a larger increase in plasma osmolality (P-osmol) at a given amount of sweat output. The increase in Posmol inhibits thermoregulatory responses to increased body core temperature. Therefore, we hypothesized that the inhibitory effect of plasma hyperosmolality on the thermoregulatory responses to heat stress should be attenuated with the reduction of [Na+](sweat) due to heat acclimatization. Eleven subjects (9 male and 2 female) were passively heated by immersing their lower legs into water at 42 degreesC (room temperature 28 degreesC and relative humidity 30%) for 50 min following isotonic or hypertonic saline infusion. We determined the increase in the esophageal temperature (T-es) required to elicit sweating and cutaneous vasodilation (CVD) (DeltaT(es) thresholds for sweating and CVD, respectively) in each condition and calculated the elevation of the T-es thresholds per unit increase in P-osmol as the osmotic inhibition of sweating and CVD. The osmotic shift in the DeltaT(es) thresholds for both sweating and CVD correlated linearly with [Na+](sweat) (r = 0.858 and r = 0.628, respectively). Thus subjects with a lower [Na+](sweat) showed a smaller osmotic elevation of the DeltaT(es) thresholds for sweating and CVD. These results suggest the possibility that heat acclimatization attenuates osmotic inhibition of thermoregulatory responses as well as reducing [Na+](sweat)., Mar. 2001, 280, 3, R623, R629, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Baroreflex modulation of peripheral vasoconstriction during progressive hypothermia in anesthetized humans, Y Nakajima; T Mizobe; A Takamata; Y Tanaka, Mild hypothermia is a major concomitant of surgery under general anesthesia. We examined the hypothesis that baroreceptor loading/unloading modifies thermoregulatory peripheral vasoconstriction and, consequently, body core temperature in subjects undergoing lower abdominal surgery with general anesthesia. Thirty-six patients were divided into four groups: control group (C), applied positive end-expiratory pressure (PEEP; 10 cmH(2)O) group (P), applied leg-up position group (L), and a group of leg-up position patients with PEEP starting 90 min after induction of anesthesia (L + P). The esophageal temperature (T-es) and the forearm-fingertip temperature gradient, as an index of peripheral vasoconstriction, were monitored for 3 h after induction of anesthesia. Mean arterial pressure and pulse pressure did not change during the study in any group. The change in right atrial transmural pressure from the baseline value was 0.3 +/- 0.1 mmHg in C, -3.0 +/- 0.5 mmHg in P, and 2.3 +/- 0.4 mmHg in L (P < 0.01). The change in Tes at the end of the study was -1.7 +/- 0.1 (35.1 +/- 0.1)degrees C in C, -1.1 +/- 0.1 (35.7 +/- 0.1)degrees C in P, and -2.7 +/- 0.1 (34.1 +/- 0.1)degrees C in L, showing significant differences (P < 0.01). The Tes threshold for thermal peripheral vasoconstriction was 35.6 +/- 0.1 degrees C in C, 36.2 +/- 0.2 degrees C in P, and 34.8 +/- 0.2 degrees C in L (P, 0.01). Excessive Tes decrease in the leg-up-position operation was attenuated by applying PEEP (L + P group; P < 0.05). Our data indicate that baroreceptor loading augments and unloading prevents perioperative hypothermia in anesthetized and paralyzed subjects by reducing and increasing the body temperature threshold for peripheral vasoconstriction, respectively., Oct. 2000, 279, 4, R1430, R1436, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Effect of acute hypoxia on vasopressin release and intravascular fluid during dynamic exercise in humans, A Takamata; H Nose; T Kinoshita; M Hirose; T Itoh; T Morimoto, To test the hypothesis that acute hypoxia does not modify the relationship between plasma vasopressin concentration ([AVP](p)) and plasma osmolality (P-osmol) during exercise and that the increase in [AVP](p) during exercise is due mainly to the exercise intensity-dependent increase in P-osmol, we examined [AVP](p) during a graded exercise in a hypoxic condition (13% O-2, N-2 balance) in seven healthy male subjects. A graded exercise in a normoxic condition on a separate day served as the control. Hypoxia reduced peak aerobic power ((V) over dotO(2 peak)) by 32.4 +/- 2.7%. Blood samples obtained during rest and at around 25, 45, 65, 80, and 100% of (V) over dotO(2) (peak) of each of the respective conditions were used for analyses of intravascular water and electrolyte balance. The pattern of the changes in fluid and electrolyte balance in response to percent (V) over dotO(2 peak) was similar between the two conditions. Plasma volume decreased linearly as percent (V) over dotO(2 peak) increased while P-osmol increased in a curvilinear fashion with a steep increase occurring at above similar to 66% (V) over dotO(2 peak). Above this relative exercise intensity, plasma sodium, potassium, and lactate concentrations also increased, whereas plasma bicarbonate concentration decreased. Thus transvascular fluid movement at above similar to 66% (V) over dotO(2 peak) was due to the net efflux of hypotonic fluid out of the vascular space in both conditions. The relationship between [AVP](p) and P-osmol during exercise in response to relative exercise intensity was similar between the two conditions. The results indicate that acute mild hypoxia itself has no direct effect on vasopressin release, and it does not modify the relationship between [AVP](p) and P-osmol during exercise. The results also support the hypothesis that exercise-induced vasopressin release is primarily stimulated by increased P-osmol produced by hypotonic fluid movement out of the vascular space in a relative exercise intensity-dependent manner., Jul. 2000, 279, 1, R161, R168, Scientific journal
  • 体力科学, (一社)日本体力医学会, サッカー選手の夏季合宿中における水分代謝の変化, 伊藤 倫之; 鷹股 亮; 武田 ひとみ; 河端 隆志, Jun. 2000, 49, 3, 441, 441
  • Not Refereed, BRAIN RESEARCH, ELSEVIER SCIENCE BV, LPS-induced Fos expression in oxytocin and vasopressin neurons of the rat hypothalamus, W Matsunaga; S Miyata; A Takamata; H Bun; T Nakashima; T Kiyohara, The aim of this study was to examine the involvement of the hypothalamic oxytocin (OXT) and vasopressin (AVP) neurons in acute phase reaction using quantitative dual-labeled immunostaining with Fos and either OXT and AVP in several hypothalamic regions. Administration of low dose (5 mu g/kg) and high dose (125 mu g/kg) of LPS induced intense nuclear Fos immunoreactivity in many OXT and AVP neurons in all the observed hypothalamic regions. The percentage of Fos-positive nuclei in OXT magnocellular neurons was higher than that of AVP magnocellular neurons in the supraoptic nucleus (SON), the magnocellular neurons in the paraventricular nucleus (magPVN), rostral SON (rSON), and nucleus circularis (NC), whose axons terminate at the posterior pituitary for peripheral release. The percentage of Fos-positive nuclei in AVP parvocellular neurons in the paraventricular nucleus (parPVN) was higher than that of OXT parvocellular neurons, whose axons terminate within the brain for central release. Moreover, the percentage of Fos-positive nuclei in AVP magnocellular neurons of the SON and rSON was significantly higher than that of the magPVN and NC when animals were given LPS via intraperitoneal (i.p.)-injection. This regional heterogeneity was not observed in OXT magnocellular neurons of i.p.-injected rats or in either OXT or AVP magnocellular neurons of intravenous (i.v.)-injected rats. The present data suggest that LPS-induced peripheral release of AVP and OXT is due to the activation of the magnocellular neurons in the SON, magPVN, NC, and rSON, and the central release of those hormones is in part derived from the activation of parvocellular neurons in the PVN. It is also suggested that the activation of AVP magnocellular neurons is heterogeneous among the four hypothalamic regions, but that of OXT magnocellular neurons is homogenous among these brain regions in response to LPS administration. (C) 2000 Elsevier Science B.V. All rights reserved., Mar. 2000, 858, 1, 9, 18, Scientific journal
  • Not Refereed, 保健の科学, スポーツと水分摂取, 鷹股 亮; 鷹股亮, 2000, 42, 332, 339
  • Not Refereed, FOOD Style 21, 運動時の水分補給とスポーツ飲料, 鷹股 亮, 2000, 6, 62, 66
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Effect of an exercise-heat acclimation program on body fluid regulatory responses to dehydration in older men, A Takamata; T Ito; K Yaegashi; H Takamiya; Y Maegawa; T Itoh; JE Greenleaf; T Morimoto, We examined if an exercise-heat acclimation program improves body fluid regulatory function in older subjects, as has been reported in younger subjects. Nine older (Old; 70 +/- 3 yr) and six younger (Young; 25 +/- 3 yr) male subjects participated in the study. Body fluid regulatory responses to an acute thermal dehydration challenge were examined before and after the B-day acclimation session. Acute dehydration was produced by intermittent light exercise [4 bouts of 20-min exercise at 40% peak rate of oxygen consumption (VO2peak) Separated by 10 min rest] in the heat (36 degrees C; 40% relative humidity) followed by 30 min of recovery without fluid intake at 25 degrees C. During the 2-h rehydration period the subjects drank a carbohydrate-electrolyte solution ad libitum. In the preacclimation test, the Old lost similar to 0.8 kg during dehydration and recovered 31 +/- 4% of that loss during rehydration, whereas the Young lost similar to 1.2 kg and recovered 56 +/- 8% (P < 0.05, Young vs. Old). During the B-day heat acclimation period all subjects performed the same exercise-heat exposure as in the dehydration period. Exercise-heat acclimation increased plasma volume by similar to 5% (P < 0.05) in Young subjects but not in Old. The body fluid loss during dehydration in the postacclimation test was similar to that in the preacclimation in Young and Old. The fractional recovery of lost fluid volume during rehydration increased in Young (by 80 +/- 9%; P < 0.05) but not in Old (by only 34 +/- 5%; NS). The improved recovery from dehydration in Young was mainly due to increased fluid intake with a small increase in the fluid retention fraction. The greater involuntary dehydration (greater fluid deficit) in Old was accompanied by reduced plasma vasopressin and aldosterone concentrations, renin activity, and subjective thirst rating (P < 0.05,Young vs. Old). Thus older people have reduced ability to facilitate body fluid regulatory function by exercise-heat acclimation, which might be involved in attenuation of the acclimation-induced increase in body fluid volume., Oct. 1999, 277, 4, R1041, R1050, Scientific journal
  • Not Refereed, JAPANESE JOURNAL OF PHYSIOLOGY, CENTER ACADEMIC PUBL JAPAN, Comparison between tail skin blood flow measurements by ultrasonic Doppler flowmetry and plethysmography during heating in anesthetized rats, Y Nakajima; H Nose; A Takamata, Tail skin blood flow (TBFu) was directly measured in anesthetized and passively heated rats by ultrasonic Doppler flowmetry during heating, and the values were compared to those (TBFp) simultaneously measured by venous-occlusion plethysmography. TBFp was estimated from the values per unit tissue multiplied by the tail volume, the shape of which was assumed to be a cone. TBFp was highly correlated with TBFu, with a regression equation of TBFp=0.7TBF(u)+0.1 (r(2)=0.94, p<0.001). Although TBFp was slightly lower than TBFu, the equation is useful to estimate the absolute values of tail skin blood flow from the values of plethysmography in awake rats., Feb. 1999, 49, 1, 121, 124, Scientific journal
  • 日本生理学雑誌, (一社)日本生理学会, パルス式色素希釈法による循環血液量測定の評価:Evans Blueによる測定との比較, 八重樫 和宏; 伊藤 倫之; 鷹股 亮; 河端 隆志; 森本 武利, Jan. 1999, 61, 1, 56, 57
  • 体力科学, (一社)日本体力医学会, 最大酸素摂取量と血液量の関係に対する年齢の影響, 伊藤 倫之; 鷹股 亮; 木村 みさか; 河端 隆志; 芳田 哲也; 森本 武利, Dec. 1998, 47, 6, 834, 834
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Plasma hyperosmolality and arterial pressure regulation during heating in dehydrated and awake rats, Y Nakajima; H Nose; A Takamata, To gain better insights into the effect of dehydration on thermal and cardiovascular regulation during hyperthermia, we examined these regulatory responses during body heating in rats under isosmotic hypovolemia and hyperosmotic hypovolemia. Rats were divided into four groups: normovolemic and isosmotic (C), hypovolemic and isosmotic [L, plasma volume loss (Delta PV) = -20% of control], hypovolemic and less hyperosmotic [HL1, increase in plasma osmolality (Delta P-osm) = 23 mosmol/kgH(2)O, Delta PV = -16%], and hypovolemic and more hyperosmotic (HL2, Delta P-osm = 52 mosmol/kgH(2)O, Delta PV = -17%). Hyperosmolality was attained by subcutaneous injection of hypertonic saline and hypovolemia by intra-arterial injection of furosemide before heating, Then rats were placed in a thermocontrolled box (35 degrees C air temperature, similar to 20% relative humidity) for 1-2 h until rectal temperatures (T-re) reached 40.0 degrees C. Mean arterial pressure in L decreased with rise in T-re (P < 0.001), whereas mean arterial pressure remained constant in the other groups. Maximal tail skin blood flow in L, HL1, and HL2 was decreased to similar to 30% of that in C (P < 0.001). T-re threshold for tail skin vasodilation (TVD) was not changed in L, whereas the threshold shifted higher in the HL groups. T-re threshold for TVD was highly correlated with P-osm (r = 0.94, P < 0.001). Heart rate in the HL groups increased with rise in T-re (P < 0.001), whereas it remained unchanged in C and L. Cardiovascular responses to heating were not influenced by V-1 antagonist in C, L, and HL2. Thus isotonic hypovolemia attenuates maximal tail skin blood flow, whereas hypertonic hypovolemia causes an upward shift of T-re threshold for TVD and an increase in heart rate during hyperthermia. These results suggest that plasma hyperosmolality stimulates presser responses in the hypovolemic condition that subsequently contribute to arterial pressure regulation during heat stress., Nov. 1998, 275, 5, R1703, R1711, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Role of plasma osmolality in the delayed onset of thermal cutaneous vasodilation during exercise in humans, A Takamata; K Nagashima; H Nose; T Morimoto, To elucidate the role of increased plasma osmolality (P-osmol), which occurs during exercise in the regulation of cutaneous vasodilation (CVD) during exercise, we determined the relationship between the change in esophageal temperature (Delta T-es) required to elicit CVD (Delta T-es threshold for CVD) and P-osmol during light and moderate exercise (30 and 55% of peak oxygen consumption, respectively) and passive body heating. Then we compared the relationship with the data obtained in our previous study [A. Takamata, K. Nagashima, H. Nose, and T. Morimoto.Am. J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42): R197-R204, 1997], in which we determined the relationships during passive body heating following isotonic (0.9% NaCl) or hypertonic (2 or 3% NaCl) saline infusions in the same subjects. P-osmol values at 5 min after the onset of exercise were 287.5 +/- 0.9 mosmol/kgH(2)O during light exercise and 293.0 +/- 1.2 mosmol/kgH(2)O during moderate exercise. P-osmol just before passive body heating was 289.9 +/- 1.4 mosmol/kgH(2)O. The Delta T-es threshold for CVD was 0.09 +/- 0.05 degrees C during light exercise, 0.31 +/- 0.09 degrees C during moderate exercise, and 0.10 +/- 0.05 degrees C during passive body heating. The relationship between the Delta T-es threshold for CVD and P-osmol was shown to be on the same regression line both during exercise and during passive body heating with or without infusions [A. Takamata, K. Nagashima, H. Nose, and T. Morimoto. Am. J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42): R197-R204, 1997]. Our data suggest that the elevated body core temperature threshold for CVD during exercise could be the result of increased P-osmol induced by exercise and is not due to reduced plasma volume or the intensity of the exercise itself., Jul. 1998, 275, 1, R286, R290, Scientific journal
  • Not Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Effect of continuous negative-pressure breathing on skin blood flow during exercise in a hot environment, K Nagashima; H Nose; A Takamata; T Morimoto, To assess the impact of continuous negative-pressure breathing (CNPB) on the regulation of skin blood flow, we measured forearm blood flow (FBF) by venous-occlusion plethysmography and laser-Doppler flow (LDF) at the anterior chest during exercise in a hot environment (ambient temperature = 30 degrees C, relative humidity = similar to 30%). Seven male subjects exercised in the upright position at an intensity of 60% peak oxygen consumption rate for 40 min with and without CNPB after 20 min of exercise. The esophageal temperature (T-es) in both conditions increased to 38.1 degrees C by the end of exercise, without any significant differences between the two trials. Mean arterial pressure (MAP) increased by similar to 15 mmHg by 8 min of exercise, without any significant difference between the two trials before CNPB. However, CNPB reduced MAP by similar to 10 mmHg after 24 min of exercise (P < 0.05). The increase in FBF and LDF in the control condition leveled off after 18 min of exercise above a T-es of 37.7 degrees C, whereas in the CNPB trial the increase continued, with a rise in T-es despite the decrease in MAP. These results suggest that CNPB enhances vasodilation of skin above a T-es of similar to 38 degrees C by stretching intrathoracic baroreceptors such as cardiopulmonary baroreceptors., Jun. 1998, 84, 6, 1845, 1851, Scientific journal
  • Not Refereed, BRAIN FUNCTION IN HOT ENVIRONMENT, ELSEVIER SCIENCE PUBL B V, Thermoregulation and body fluid in hot environment, T Morimoto; T Itoh; A Takamata, 1998, 115, 499, 508
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Osmoregulatory inhibition of thermally induced cutaneous vasodilation in passively heated humans, A Takamata; K Nagashima; H Nose; T Morimoto, We examined the effect of increased plasma osmolality (P-osm) on cutaneous vasodilatory response to increased esophageal temperature (T-es) in passively heated human subjects (n = 6). To modify P-osm, subjects were infused with 0.9, 2, or 3% NaCl infusions (Inf) for 90 min on separate days. Infusion rates were 0.2, 0.15, and 0.125 ml . min(-1). kg body wt(-1) for 0.9, 2, and 3% Inf, respectively, which produced relatively similar plasma volume expansion. Thirty minutes after the end of infusion, subjects immersed their lower legs in a water bath at 42 degrees C (room temperature 28 degrees C) for 60 min after 10 min of preheating control measurements. Passive heating without infusion (NI) served as time control to account for the effect of volume expansion. P-osm (mosmol/kgH(2)O) values at the onset of passive heating were 289.9 +/- 1.4, 292.1 +/- 0.6, 298.7 +/- 0.7, and 305.6 +/- 0.6 after NI, 0.9% Inf, 2% Inf, and 3% Inf, respectively. The increases in T-es (Delta T-es) at equilibrium during passive heating (mean Delta T-es during 55-60 min) were 0.47 +/- 0.08, 0.59 +/- 0.08, 0.85 +/- 0.13, and 1.09 +/- 0.12 degrees C after NI, 0.9% Inf, 2% Inf, and 3% Inf, respectively, which indicates that T-es at equilibrium increased linearly as P-osm increased. Delta T-es required to elicit cutaneous vasodilation (Delta T-es threshold for cutaneous vasodilation) also increased linearly as P-osm increased as well as the Delta T-es threshold for sweating. The calculated increases in these thresholds per unit rise in P-osm from regression analysis were 0.044 degrees C for the cutaneous vasodilation and 0.034 degrees C for sweating. Thus the Delta T-es thresholds for cutaneous vasodilation and sweating are shifted to higher Delta T-es along with the increase in P-osm, and these shifts resulted in the higher increase in T-es during passive heating., Jul. 1997, 273, 1, R197, R204, Scientific journal
  • Not Refereed, INTERNATIONAL JOURNAL OF BIOMETEOROLOGY, SPRINGER VERLAG, Integrative regulations of body temperature and body fluid in humans exercising in a hot environment, H Nose; A Takamata, Feb. 1997, 40, 1, 42, 49, Scientific journal
  • Not Refereed, THERMOREGULATION, NEW YORK ACAD SCIENCES, Negative pressure breathing and the control of skin blood flow during exercise in a hot environment, K Nagashima; T Yoshida; H Nose; A Takamata; T Morimoto, 1997, 813, 604, 609, Scientific journal
  • Not Refereed, Space Utilization Research., 静脈還流量からみた微少重力下での筋血流調節, 鷹股 亮; 能勢博; 上条義一郎; 竹野欽昭; 柳平担徳; 酒井秋男; 永島計; 鷹股亮; 森本武利, 1997, 14, 18, 21
  • Not Refereed, 臨床スポーツ医学, 運動時の体液調節, 鷹股 亮, 1997, 14, 721, 727
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, Thirst and fluid regulatory responses to hypertonicity in older adults, NS Stachenfeld; GW Mack; A Takamata; L DiPietro; ER Nadel, To assess the fluid regulatory responses in aging adults, we measured thirst perception and renal osmoregulation during and after infusion of hypertonic (3% NaCl) saline in older (72 +/- 2 yr, n = 6) and younger (26 +/- 2 yr, n = 6) subjects. Hypertonic saline was infused at 0.1 ml . min(-1). kg(-1) for 120 min. On a separate day, the same subjects were infused identically with isotonic saline as a control. After infusion and a 30-min equilibration period, the subjects drank water ad libitum for 180 min. Hypertonic saline infusion Zed to graded increases in plasma osmolality (P-osm; 18 +/- 2 and 20 +/- 2 mosmol/kgH(2)O) and percent changes in plasma volume (16.2 +/- 1.9 and 18.0 +/- 1.2%) that were similar in older and younger subjects. Osmotically stimulated increases in thirst (94.8 +/- 18.9 and 88.3 +/- 25.6 mm), assessed on a line rating scale, and plasma arginine vasopressin concentration (6.08 +/- 1.50 and 4.51 +/- 1.37 pg/ml, for older and younger, respectively) were also unaffected by age. Despite subsequent hypervolemia, both groups of subjects drank sufficient water to restore preinfusion levels of P-osm. Renal handling of free water and sodium was also unaffected by age during recovery from hypertonic saline infusion, but was significantly lower in older subjects during recovery from isotonic saline infusion, resulting in net fluid retention and a significant fall in P-osm (6 mosmol/kgH(2)O). In contrast to earlier reports of a blunted thirst response to dehydration and hypertonicity, we found that osmotically stimulated thirst and renal osmoregulation were intact in older adults after hypertonic saline infusion., Sep. 1996, 271, 3, R757, R765, Scientific journal
  • Not Refereed, 日常診療と血液, スポーツが血中イオンに及ぼす影響と循環血液量の変化について, 鷹股 亮, 1996, 6, 403, 409
  • Not Refereed, 臨床スポーツ医学, 運動時の体温調節と水分摂取., 鷹股 亮, 1996, 13, 68, 73
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, BODY-TEMPERATURE MODIFICATION OF OSMOTICALLY INDUCED VASOPRESSIN SECRETION AND THIRST IN HUMANS, A TAKAMATA; GW MACK; NS STACHENFELD; ER NADEL, We examined the effect of increased body core temperature (T-es) on the plasma arginine vasopressin concentration ([AVP](p)) and thirst responses to increased plasma osmolality (P-osm) induced by 3% NaCl infusion for 120 min in seven healthy humans. T-es was increased by immersion of the lower legs in 41 degrees C water in a 28 degrees C room (passive heating; HT). Immersion of the lower legs in 34.5 degrees C water on a separate day served as the control (thermoneutral; NT). The 120-min hypertonic saline infusion was initiated 30 min after the onset of leg immersion and was followed by a 30-min rehydration period. T-es in HT increased by 0.21 +/- 0.04 degrees C before infusion and by 0.86 +/- 0.08 degrees C at the end of infusion. The change in T-es in NT before and after the infusion was negligible. P-osm was increased by 15.0 +/- 1.0 mosmol/kgH(2)O by infusion in both NT and HT. [AVP](p) increased by 3.48 +/- 0.72 pg/ml in NT and by 7.59 +/- 1.02 pg/ml in HT. Thus the increase in [AVP](p) at a given increase in P-osm was markedly higher in HT than in NT. The plasma renin activity response to hypertonic saline infusion in both conditions was similar. Subjective thirst rating and cumulative water intake during rehydration were higher in HT than in NT. The calculated increase in [AVP](p) per unit rise in T-es at a P-osm of 299 +/- 1 mosmol/kgH(2)O was 4.23 +/- 0.85 pg . ml(-1).degrees C-1, significantly higher than the 1.68 +/- 1.10 pg . ml(-1).degrees C-1 increase at a P-osm of 284 +/- 1 mosmol/kgH(2)O. Our data indicate that the effect of increased T-es and P-osm on [AVP](p) is not simply additive but P-osm dependent. We conclude that increased T-es modulates osmotically induced AVP secretion in a P-osm-dependent manner., Oct. 1995, 269, 4, R874, R880, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, OSMOREGULATORY MODULATION OF THERMAL SWEATING IN HUMANS - REFLEX EFFECTS OF DRINKING, A TAKAMATA; GW MACK; CM GILLEN; AC JOZSI; ER NADEL, To gain better insight into the interaction between thermoregulation and osmoregulation, we examined the thermal sweating response to drinking in cell-dehydrated humans. Cell dehydration (CDH) was induced by infusion of a 3% NaCl solution, at 1.2 ml/kg, for 2 h; infusion of a 0.9% NaCl solution in a separate experiment served as a control (euhydrated condition, EH). After infusion, subjects were heated by immersion of the lower legs in 42 degrees C water at an ambient temperature of 28 degrees C for 90 min. Subjects drank 4.3 ml/kg of H2O (similar to 38 degrees C) at 60 min of heating. The 3% NaCl infusion increased plasma osmolality by 13.6 +/- 0.8 mosmol/kgH(2)O and plasma arginine vasopressin concentration ([AVP]) by 3.3 +/- 0.7 pg/ml. Neither variable was altered with 0.9% NaCl infusion. Before drinking, esophageal temperature (T-es) had increased by 0.91 +/- 0.08 degrees C in CDH and by 0.40 +/- 0.11 degrees C in EH. Local chest sweating rate (SR(ch)) had increased by 0.67 +/- 0.08 and 0.63 +/- 0.07 mg . min(-1) . cm(-2) in CDH and EH, respectively. Thus the change in SR(ch) per unit rise in T-es was much lower in CDH than in EH. Drinking immediately increased SR(ch) and reduced T-es in CDH, with a reduction in plasma [AVP] and thirst rating. Drinking did not change thermoregulatory and osmoregulatory responses in EH. These results suggest that the act of drinking itself eliminates, at least partially, an osmotic inhibitory input to the thermoregulatory center, as well as osmotic AVP secretion and thirst., Feb. 1995, 268, 2, R414, R422, Scientific journal
  • Not Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, RIGHT ATRIAL PRESSURE AND ANP RELEASE DURING PROLONGED EXERCISE IN A HOT ENVIRONMENT, H NOSE; A TAKAMATA; GW MACK; T KAWABATA; Y ODA; S HASHIMOTO; M HIROSE; E CHIHARA; T MORIMOTO, To investigate the relationship between right atrial pressure (RAP) and atrial natriuretic peptide (ANP) release during prolonged exercise in a hot environment (30 degrees C, 20% relative humidity), we studied with a Swan-Ganz catheter five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min. The ANP level increased from 14 +/- 3 (SE) to 69 +/- 10 pg/ml (P < 0.001) during the first 10 min of exercise as RAP rose from 4.3 +/- 0.8 to 6.9 +/- 1.1 mmHg (P < 0.001). The 10-min ANP level was significantly correlated with RAP (r = 0.88, P < 0.05) but not with heart rate, pulmonary arterial blood temperature, plasma norepinephrine, or plasma epinephrine. The 10-min RAP value was inversely correlated with blood volume (r = -0.98, P < 0.01) and also with stroke volume (r = -0.96, P < 0.01). In the next 20 min of exercise, ANP continued to increase to 101 +/- 12 pg/ml (P < 0.02 vs. 10 min) and remained at this level until 50 min of exercise, whereas RAP decreased and reached a level not significantly different from baseline at 50 min (5.7 +/- 1.0 mmHg; P < 0.01 vs. 10 min). This dissociation of ANP and RAP may have been related to the significant increases from the 10-min values of heart rate, blood temperature, norepinephrine (all P < 0.01), and epinephrine (P < 0.02) during the same period. These results suggest that ANP release is primarily controlled by atrial distension at the onset of exercise but that other stimulators may be involved thereafter. The lower ANP release in subjects with a higher blood volume at 10 min may have been caused by an attenuated increase in RAP due to a larger stroke volume., May 1994, 76, 5, 1882, 1887, Scientific journal
  • Not Refereed, AMERICAN JOURNAL OF PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, SODIUM APPETITE, THIRST, AND BODY-FLUID REGULATION IN HUMANS DURING REHYDRATION WITHOUT SODIUM REPLACEMENT, A TAKAMATA; GW MACK; CM GILLEN; ER NADEL, After a 7-h H2O and Na+ depletion period (DP), produced by intermittent light exercise (8 bouts) at 35 degrees C, we examined thirst and taste palatability responses to 10 different NaCl solutions during 23 h of rehydration (RH) at 25 degrees C. During DP, net H2O and Na+ loss were 27.2 +/- 2.9 ml/kg and 3.29 +/- 0.45 meq/kg, respectively. Plasma osmolality (P-Osm) and plasma Na+ concentration ([Na+](p)) increased significantly during DP by 3.4 +/- 1.2 mosmol/kgH(2)O and 3.0 +/- 1.0 meq/kgH(2)O, respectively. Plasma volume (PV) decreased by 6.5 +/- 1.9%. Thirst rating, renal fractional reabsorption of H2O, and plasma arginine vasopressin concentration (P-AVP) increased as P-Osm increased. This increased thirst was accompanied by increased palatability ratings to H2O. During RH, subjects drank deionized H2O ad libitum and ate a Na+-free diet for 23 h. P-Osm and [Na+](p) returned to control levels within 1 h RH and remained at or below the control thereafter. PV remained reduced by similar to 5% throughout RH. The increased thirst and P-AVP returned to their respective control levels within 1 h of RH as P-Osm decreased, but thirst rating increased again between 17 and 23 h of RH without an increase in P-Osm or P-AVP. Palatability ratings to a 1 M NaCl solution at and after 3 h RH and palatability ratings to 0.3 M at 17 and 23 h RH were significantly higher than control. Plasma aldosterone concentration (P-Aldo) increased after DP, decreased with drinking, and increased again between 6 and 23 h of RH, accompanied by a marked decrease in fractional Na+ excretion to <0.07%. Thus both Na+ preference and thirst in humans are influenced by body fluid and electrolyte status. The increased Na+ palatability (Na+ appetite) was preceded by osmotically induced thirst, and accompanied by nonosmotically driven thirst [extracellular fluid (ECF) thirst] and increased P-Aldo. The ''Na+ appetite'' and ''ECF thirst'' along with increased renal Na+ retention could contribute to ECF volume regulation after thermally induced H2O and Na+ depletion., May 1994, 266, 5, R1493, R1502, Scientific journal
  • Not Refereed, PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, SPRINGER VERLAG, RIGHT ATRIAL PRESSURE AND FOREARM BLOOD-FLOW DURING PROLONGED EXERCISE IN A HOT ENVIRONMENT, H NOSE; A TAKAMATA; GW MACK; Y ODA; T KAWABATA; S HASHIMOTO; M HIROSE; E CHIHARA; T MORIMOTO, Right atrial pressure (RAP) at rest is known to be reduced by an increase in skin blood flow (SkBF) in a hot environment. However, there is no clear evidence that this is so during exercise. To clarify the effect of the increase in SkBF on RAP during exercise, we measured forearm blood flow (FBF) (as an index of SkBF) and RAP continuously using a Swan-Ganz catheter in five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min in a hot environment (30 degrees C, relative humidity 20%). Cardiac output increased from 5.5 +/- 0.2 l/min at rest to 17.9 +/- 1.2 l/min (mean +/- SE, P < 0.01) in the first 10 min of exercise and then remained steady until the end of exercise. FBF did not change significantly during the first 5 min, but then increased from 2.7 +/- 0.5 ml/100 ml per min at rest to 10.8 +/- 1.7 ml/100 ml per min (P < 0.001) by 25 min as pulmonary arterial blood temperature (T-b) rose from 37.0 +/- 0.1 degrees C to 38.1 +/- 0.1 degrees C (P < 0.001). FBF then reached a plateau, despite a continuing increase in T,. RAP increased significantly from 4.3 +/- 0.8 to 7.6 +/- 1.2 mm Hg (P < 0.001) during the first 5 min of exercise and then gradually declined to 6.1 +/- 1.0 mm Hg by 25 min (P < 0.001 vs. 5 min) and further to 5.7 +/- 1.0 mm Hg by 50 min, a value not significantly higher than at rest. This reduction in RAP during exercise was significantly correlated with the increase in FBF (r = -0.97, P < 0.001) with a regression equation of RAP = -0.25XFBF + 8.8. These results suggest that the decrease in RAP after 5 min exercise was caused by an increase in SkBF during exercise in a hot environment., Feb. 1994, 426, 3-4, 177, 182, Scientific journal
  • Not Refereed, MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, WILLIAMS & WILKINS, INFLUENCE OF EXERCISE INTENSITY AND PLASMA-VOLUME ON ACTIVE CUTANEOUS VASODILATION IN HUMANS, GW MACK; H NOSE; A TAKAMATA; T OKUNO; T MORIMOTO, The influence of dynamic exercise on active cutaneous vasodilation was evaluated in eight male subjects. We measured the increase in internal body temperature (esophageal temperature, T-es) required to elicit active cutaneous vasodilation and the slope of the linear relationship between increases in forearm skin vascular conductance (Delta FVC) and T-es during indirect heating (legs immersed in 44 degrees C water for 30 min), 30 min of light exercise (LEX; 75 +/- 5 W = 30% maximal oxygen uptake, VO2max), and 20 min of moderate exercise (MEX, 149 +/- 7 W = 60% VO2max) Studies were conducted in the supine position at 30 degrees C (RH <30%) and mean skin temperature averaged 35.09 +/- 0.12 degrees C. During indirect heating and LEX, cutaneous vasodilation occurred after a similar increase in T-es, 0.03 +/- 0.02 degrees C and 0.11 +/- 0.02 degrees C, respectively. During MEX, T-es increased 0.42 +/- 0.06 degrees C before the onset of cutaneous vasodilation (P < 0.05, different from rest and LEX). The relationship between the increase in T-es threshold for vasodilation and exercise intensity was nonlinear, indicating that some minimal exercise intensity was required to elicit a delay in active cutaneous vasodilation. That minimal exercise intensity was greater than 30% VO2max (75 +/- 5 W). During MEX the increase in T-es threshold for vasodilation was inversely related to resting plasma volume (ml . kg(-1)) with a larger initial plasma volume associated with a smaller increase in T-es threshold for cutaneous vasodilation (r(2) = 0.67, P = 0.03). In addition, peak cutaneous vasodilation represented as the peak Delta FVC/peak Delta T-es, was directly related to plasma volume (r(2) = 0.64, P = 0.03). We conclude that the influence of exercise on the threshold for active cutaneous vasodilation is dependent on an interaction between exercise intensity and the size of the intravascular compartment. This conclusion is consistent with the hypothesis that blood volume expansion is an important adaptation of exercise training and contributes to improved thermoregulatory control during exercise in the heat., Feb. 1994, 26, 2, 209, 216, Scientific journal
  • Not Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, MEASUREMENT OF PLASMA-VOLUME IN RATS WITH USE OF FLUORESCENT-LABELED ALBUMIN MOLECULES, CM GILLEN; A TAKAMATA; GW MACK; ER NADEL, We describe a method for measuring plasma volume (PV) in small animals that allows small sample sizes but does not require the use of radioisotopes and thus is a convenient approach for making repeated measurements. Texas Red covalently bound to albumin (TR-A) was used in a typical indicator-dilution technique to measure PV. The relative fluorescent intensity of TR-A is linear to its concentration (up to 0.15 mg/ml) at an excitation lambda of 590 nm and an emission lambda of 610 nm. Catheters were inserted through the right jugular vein of anesthetized rats and threaded into the vena cava. A 0.5-ml control blood sample was taken, a measure quantity of TR-A was injected, and the catheter was flushed with saline. A 0.5-ml postinjection sample was taken 5 min after TR-A injection. PV was calculated by comparing the difference between the relative fluorescent intensity of control and postinjection plasma samples to a standard. The PV of 22 rats [362 +/- 14 (SE) g] was 14.1 +/- 0.4 ml (39.6 +/- 0.9 ml/kg body wt) measured by the TR-A method and 12.8 +/- 0.4 ml (35.9 +/- 1.0 ml/kg body wt) measured by a standard radioiodinated albumin method. There was a strong correlation between PV measured by both methods in the same rat (r = 0.90, P < 0.01). Infusion experiments indicated that the TR-A method can detect acute changes in PV, and repeated measurements of PV made on a chronically instrumented rat demonstrated that the method can reliably measure PV on consecutive days., Jan. 1994, 76, 1, 485, 489
  • Not Refereed, JAPANESE JOURNAL OF PHYSIOLOGY, CENTER ACADEMIC PUBL JAPAN, EFFECT OF VAGOTOMY ON CARDIOVASCULAR ADJUSTMENT TO HYPERTHERMIA IN RATS, A TAKAMATA, To elucidate the contribution of cardiopulmonary baroreflexes on the control of total peripheral vascular conductance (TVC) during hyperthermia, alpha-chloralose-anesthetized rats with (VX-groups) or without (C-groups) vagotomy were subjected to body heating raising arterial blood temperature (T(b)) at a rate of 0.1-degrees-C/min. In both the C- and VX-groups, rats were divided into normovolemia (C-NBV and VX-NBV) and furosemide-induced hypovolemia (C-LBV and VX-LBV) and cardiovascular responses to hyperthermia were compared between the four groups. Central venous pressure (CVP) decreased as T(b) rose to 43-degrees-C by 1.92 +/- 0.24, 1.36 +/- 0.28, 0.62 +/- 0.14, and 0.35 +/- 0.23 mmHg in the C-NBV, VX-NBV, C-LBV, and VX-LBV groups, respectively. Mean arterial pressure increased by 35-45 mmHg in the C-groups and by 25-35 mmHg in the VX-groups at T(b) of 42-43-degrees-C in the C-groups and 42-degrees-C in the VX-groups. Heart rate response to increased T(b) was not affected by vagotomy or LBV. Stroke volume correlated with CVP (r = 0.769) and this relationship did not differ among the four groups. TVC was more highly correlated with CVP in the C-groups (r = 0.925) than in the VX-groups (r = 0.757). The slope of TVC vs. CVP (TVC/CVP) for the VX-groups lowered by about 40% from that for the C-groups. These results suggest that during hyperthermia, cardiopulmonary baroreflexes may partly contribute to the control of TVC, and other mechanisms related to decreased BV and increased T(b) play some roles in the control of TVC., 1992, 42, 4, 641, 652, Scientific journal
  • Not Refereed, 京都府立医科大学雑誌, 低酸素負荷による睡眠時血圧動揺の解析, 鷹股 亮; 仲井幹雄; 能勢博; 猪田浩史; 陳勉; 鷹股亮; 池内隆治; 森本武利, 1992, 101, 625, 633
  • Not Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, WATER AND ELECTROLYTE BALANCE IN THE VASCULAR SPACE DURING GRADED-EXERCISE IN HUMANS, H NOSE; A TAKAMATA; GW MACK; Y ODA; T OKUNO; DH KANG; T MORIMOTO, We analyzed the changes in water content and electrolyte concentrations in the vascular space during graded exercise of short duration. Six male volunteers exercised on a cycle ergometer at 20-degrees-C (relative humidity = 30%) as exercise intensity was increased stepwise until voluntary exhaustion. Blood samples were collected at exercise intensities of 29, 56, 70, and 95% of maximum aerobic power (Vo2max). A curvilinear relationship between exercise intensity and Na+ concentration in plasma ([Na+]p) was observed. [Na+]p significantly increased at 70% Vo2max and at 95% Vo2max was approximately 8 meq/kgH2O higher than control. The change in lactate concentration in plasma ([Lac-]p) was closely correlated with the change in [Na+]p (DELTA[Na+]p = 0.687 DELTA[Lac-]p + 1.79, r = 0.99). The change in [Lac-]p was also inversely correlated with the change in HCO3- concentration in plasma (DELTA[HCO3-]p = -0.761 DELTA[Lac-]p + 0.22, r = -1.00). At an exercise intensity of 95% Vo2max, 60% of the increase in plasma osmolality (Posmol) was accounted for by an increase in [Na+]p. These results suggest that lactic acid released into the vascular space from active skeletal muscles reacts with [HCO3-]p to produce CO2 gas and Lac-. The data raise the intriguing notion that increase in [Na+]p during exercise may be caused by elevated Lac-., Jun. 1991, 70, 6, 2757, 2762, Scientific journal
  • Refereed, Journal of Applied Physiology, Water and electrolyte balance in the vascular space during graded exercise in humans, H. Nose; A. Takamata; G. W. Mack; Y. Oda; T. Okuno; D. H. Kang; T. Morimoto, We analyzed the changes in water content and electrolyte concentrations in the vascular space during graded exercise of short duration. Six male volunteers exercised on a cycle ergometer at 20°C (relative humidity = 30%) as exercise intensity was increased stepwise until voluntary exhaustion. Blood samples were collected at exercise intensities of 29, 56, 70, and 95% of maximum aerobic power (V̇O(2 max)). A curvilinear relationship between exercise intensity and Na+ concentration in plasma ([Na+]p) was observed. [Na+]p significantly increased at 70% V̇O(2 max) and at 95% V̇O(2 max) was ~8 meq/kgH2O higher than control. The change in lactate concentration in plasma ([Lac-]p) was closely correlated with the change in [Na+]p (Δ[Na+]p = 0.687 Δ[Lac-]p + 1.79,r = 0.99). The change in [Lac-]p was also inversely correlated with the change in HCO-/3 concentration in plasma (Δ[HCO-/3]p = -0.761 Δ[Lac-]p + 0.22, r = -1.00). At an exercise intensity of 95% V̇O(2 max), 60% of the increase in plasma osmolality (Posmol) was accounted for by an increase in [Na+]p. These results suggest that lactic acid released into the vascular space from active skeletal muscles reacts with [HCO-/3]p to produce CO2 gas and Lac-. The data raise the intriguing notion that increase in [Na+]p during exercise may be caused by elevated Lac-., 1991, 70, 6, 2757, 2762, Scientific journal
  • Not Refereed, JOURNAL OF APPLIED PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, CONTROL OF TOTAL PERIPHERAL RESISTANCE DURING HYPERTHERMIA IN RATS, A TAKAMATA; H NOSE; GW MACK; T MORIMOTO, Sep. 1990, 69, 3, 1087, 1092, Scientific journal
  • Refereed, Journal of Applied Physiology, Control of total peripheral resistance during hyperthermia in rats, A. Takamata; H. Nose; G. W. Mack; T. Morimoto, To elucidate the effect of blood volume on the circulatory adjustment to heat stress, we studied α-chloralose-anesthetized rats at three levels of blood volume: normovolemia (NBV), hypervolemia (HBV +32% plasma volume by isotonic albumin solution infusion), and hypovolemia (LBV -16% plasma volume by furosemide administration). Body surface heating was performed with an infrared lamp to raise arterial blood temperature (T(b)) at the rate of ~0.1°C/min. Before heating, central venous pressure (CVP) was significantly higher in HBV (0.41 ± 0.25 mmHg) and lower in LBV (-1.44 ± 0.22 mmHg) than in NBV (-0.41 ± 0.10 mmHg). The T(b) at which CVP started to decrease was ~40°C in HBV, ~41°C in NBV, and ~42°C in LBV, and it decreased by 1.53 ± 0.14, 1.92 ± 0.24, and 0.62 ± 0.14 mmHg from 37 to 43°C of T(b) in HBV, NBV, and LBV, respectively. Stroke volume was closely correlated with CVP, and this relationship was not affected by T(b). Heart rate responses to the raised T(b) were similar among the three groups. Mean arterial pressure (MAP) was not affected by blood volume modification or CVP and was maintained at preheating (T(b) 37°C) level until T(b) rose to 40°C. Above this T(b), MAP increased until T(b) reached 43°C (+30-40 mmHg) for all three groups. Total peripheral resistance (TPR) was inversely correlated with CVP, and the slope of the linear relationship between TPR and CVP in LBV was three- to fourfold steeper than in NBV or HBV. These results suggest that the control of TPR during severe hyperthermia (T(b) > 40°C) is influenced by T(b) and also by a cardiopulmonary baroreflex in response to a fall in CVP., 1990, 69, 3, 1087, 1092, Scientific journal
  • Not Refereed, アルコール代謝と肝, 遊泳運動による摂取エタノールの生体内分布の変動と体温調節反応, 鷹股 亮; 今泉和彦; 立屋敷かおる; 鷹股亮; 荻田善一, 1988, 7, 85, 93
  • Not Refereed, Eiyo To Shokuryo, Japan Society of Nutrition and Food Science, Role of contents in stomach to the circadian variation of plasma ethanol concentration in the rat., TACHIYASHIKI Kaoru; IMAIZUMI Kazuhiko; TODA Noriko; TAKAMATA Akira; UESUGI Kuniko; OGITA Zen-Ichi, To investigate the mechanism responsible for the circadian variation of elimination processes of ethanol (EtOH), EtOH (100mg/100g B.W.) was orally administered to female Sprague-Dawley rats at 8: 00 and 20: 00 under non-fasting conditions, and EtOH concentration in plasma prepared from tail venous blood was determined with gaschromatograph at constant intervals. The intakes of feed and water 12 hours before oral administration of EtOH were also measured to elucidate the relationship between feed intake or water intake and each parameter obtained from the time course of plasma EtOH concentration (p [EtOH]). Immediately after EtOH was disappeared in Plasma, the rats were decapitated. Concentration of EtOH in stomach and the content in stomach for each rat were measured, and specific activity of alcohol dehydrogenase (ADH) in liver was determined spectrophotometrically at 37°C and pH 9. Solid feed and water were given to rats ad libitum during the light period (8: 00-20: 00) and the dark period (20: 00-8: 00). The feed intakes from 20: 00 to 8: 00 and from 8: 00 to 20: 00 were 5.7±1.6mg·g-1 B.W. ·hr-1 and 1.6±0.7mg·g-1 B.W. ·hr-1, respectively. The former was bigger than the latter. The water intake during the dark period was 2.2 times bigger than that during the light period. Therefore, the feed and water intakes during the dark period were higher than those during the light period. The max. p [EtOH] (A), the time to reach max. p [EtOH] (B), the time of pEtOH disappearance (C) and integration value of pEtOH (D) obtained from the dark period were 2.0, 1.5, 1.6 and 3.2 times bigger than those obtained from the light period, respectively. This means that there is the diurnal rhythm of the time course of p [EtOH]. Liver ADH activity showed nonsignificant change between the light period and the dark period. The remaining rates of EtOH in the stomach (= (Content of EtOH in stomach/total content of EtOH administered) ×100) were 25.8±10.7% for the light period, and 0.3±0.4% for the dark period, the former was 86 times higher than the latter. Therefore, A, B, C and D showed the diurnal variation under the non-fasting conditions. However, apparent decay rate constant (k) of EtOH showed no diurnal variation in both groups. There was bigh negative correlation (γ≅ -0.8) between each parameter (A, B, C and D) except k value and the remaining rate of EtOH in stomach. From these results, it is likely that the diurnal rhythm of p [EtOH] under non-fasting conditions is controlled by the remaining rate of EtOH in stomach and independent of the change of liver ADH activity., 1987, 40, 1, 35, 42
  • Not Refereed, アルコール代謝と肝, エタノールの生体内分布の動的解析, 鷹股 亮; 今泉和彦; 立屋敷かおる; 鷹股亮; 戸田典子; 蒲田直明, 1987, 6, 66, 74
  • Not Refereed, アルコール代謝と肝, 肝エタノール代謝に及ぼす運動の影響, 鷹股 亮; 今泉和彦; 立屋敷かおる; 佐々木友子; 長野肇; 大滝優子; 鷹股亮, 1986, 5, 242, 250
  • Refereed, Mar. 2022, 10, 5, e15193
  • JJSCA, THE JAPAN SOCIETY FOR CLINICAL ANESTHESIA, Anesthesia and operation and body fluid metabolism. Effect of the body fluid osmotic change on the circulation regulation., 能勢 博; 広瀬 宗孝; 中嶋 康文; 鷹股 亮; 陳 勉, 1997, 17, 10, 585, 588

MISC

  • Not Refereed, デサントスポーツ科学, 運動時の全身循環および体温調節機能をサポートする下肢圧迫法の開発, 鷹股 亮; 鷹股亮, 2005, 24, 95, 102
  • Not Refereed, デサントスポーツ科学, 石本記念デサントスポ-ツ科学振興財団事務局, 運動トレーニングおよび暑熱馴化時の体温調節機能の亢進における浸透圧調節系の役割, 鷹股 亮; 鷹股亮; 芳田哲也, 1998, 19, 19, 116, 123
  • Not Refereed, 宇宙利用シンポジウム, The Modification of Venous Return by Continuous Negative Pressure Breathing and its Effect on Skin Blood Flow., 森本武利; 永島計; 能勢博; 鷹股亮, Sep. 1996, 13th, 55, 58
  • Not Refereed, 長崎大学熱帯医学研究所共同研究報告集, Central venous pressure and thermoregulatory reaction. (Nagasaki Univ., Inst. for Tropical Medicine S), 永島計; 能勢博; 鷹股亮; 森本武利, 30 Jun. 1996, 1995, 136
  • Not Refereed, 小野スポーツ科学, 血漿浸透圧の上昇が温熱負荷時の皮膚血流調節に及ぼす影響とその個人差, 鷹股 亮; 鷹股亮; 永島計; 能勢博, 1996, 4, 109, 122
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Estradiol-modification of Blood Pressure Regulatory Response to Systemic and Central Angiotensin II Administration in Rats, Akira Takamata; Natsumi Omura; Yuri Nishimura; Ayako Igarashi; Keiko Morimoto, Apr. 2015, 29, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Estradiol Replacement Attenuates Central Body Fluid Regulatory Responses to Hyperosmolality and Central Angiotensin II in Ovariectomized Rats, Natsumi Omura; Yuri Nishimura; Ayako Igarashi; Akira Takamata, Apr. 2015, 29, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Effect of Estradiol Replacement on Diurnal Sleep/Wake Pattern in Ovariectomized Rats Measured with a Subcutaneously Implanted Acceleration Sensor, Ayako Igarashi; Natsumi Omura; Megumi Miura; Nanako Mima; Yuri Nishimura; Kaori Mabuchi; Akira Takamata, Apr. 2015, 29, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, The effects of menstrual phase on brachial artery endothelial function after mental stress in young women, Xin Chen; Kyoko Ueshima; Mika Omokute; Akira Takamata; Keiko Morimoto, Apr. 2015, 29, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Estradiol replacement attenuates stress-induced pressor response by regulating renin-angiotensin system in ovariectomized rats, Yu Nagatomo; Shoko Tazumi; Risa Itoh; Misa Yoshimoto; Akira Takamata; Keiko Morimoto, Apr. 2015, 29, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Serotonin is possibly involved in the anorexigenic and antidepressant effects of estrogen in ovariectomized rats, Yuri Nishimura; Kaori Mabuchi; Hiroko Negishi; Keiko Morimoto; Akira Takamata, Apr. 2013, 27, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Orchiectomy increases food intake and perifornical orexin A neuron's activity during glucoprivation, Akira Takamata; Kana Miyake; Kaori Mabuchi; Keiko Morimoto, Apr. 2013, 27, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER JAPAN KK, Removal of photic stimulation impairs estrogen-induced anorexia in rats, Kaori Mabuchi; Azusa Takano; Yayoi Hara; Keiko Morimoto; Akira Takamata, 2013, 63, S255, S255, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Orexigenic and obesity effects of estrogen deficiency can be attenuated by half-day food deprivation either during the light phase or the dark phase, Sayumi Taguchi; Kaori Mabuchi; Azusa Takano; Yayoi Hara; Keiko Morimoto; Akira Takamata, Apr. 2012, 26, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Involvement of orexin A and melanin concentrating hormone neurons of the lateral hypothalamic area in the food intake response to reduced glucose availability, Akira Takamata; Sayumi Taguchi; Saori Ikeda; Eri Aida; Keiko Morimoto, Apr. 2012, 26, Summary international conference
  • Not Refereed, EUROPEAN JOURNAL OF ANAESTHESIOLOGY, LIPPINCOTT WILLIAMS & WILKINS, Effect of central angiotensin II receptor antagonist and endogenous vasopressin on blood pressure regulation during normotension endotoxemia in rats, F. Shimizu; T. Kasai; S. Inoue; A. Takamata, Jun. 2010, 27, 1, 171, 171, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, Estrogen attenuates food intake and hypothalamic c-Fos expression in response to reduced glucose availability during light phase, Akira Takamata; Kana Miyake; Kotomi Ueda; Mami Miyake; Megumu Hasegawa; Yuko Nakamura; Yoko Fujita; Keiko Morimoto, 2010, 60, S181, S181, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, Roles of oxidative stress on the reduction of forearm blood flow induced by mental stress in postmenopausal women, Keoko Morimoto; Kozue Ohyama; Mai Motohiro; Shigenobu Yano; Akira Takamata, 2010, 60, S58, S58, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Role of light in the estrogen deficiency-induced changes in diurnal SCN neural activity and food intake, Kana Miyake; Keiko Morimoto; Akira Takamata, Apr. 2009, 23, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Estrogen attenuates food intake and perifornical orexinergic neuron's activity during glucoprivation in ovariectomized rats, Akira Takamata; Kana Miyake; Keiko Morimoto, Apr. 2009, 23, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, EFFECTS OF ESTROGEN REPLACEMENT ON OXIDATIVE STRESS IN VASCULATURE RELATED TO PSYCHOLOGICAL STRESS IN OVARIECTOMIZED RATS, Ai Ikehata; Mizuho Kawakami; Sumire Ohkawa; Asumi Yoshida; Masami Uji; Akira Takamata; Ken-ichi Yoshida; Keiko Morimoto, 2009, 59, 497, 497, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, EFFECTS OF ESTROGEN ON STRESS-INDUCED ACTIVATION OF NITRIC OXIDE PRODUCING NEURONS IN PARAVENTRICULAR HYPOTHALAMIC NUCLEUS OF RATS, Yurina Omuro; Tomoko Hata; Yasuko Hara; Akira Takamata; Takashi Ueyama; Keiko Morimoto, 2009, 59, 333, 333, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, ESTROGEN DEFICIENCY MODIFIES DIURNAL RHYTHMS OF SCN ACTIVITY AND BEHAVIORS BY CHANGING THE RESPONSE TO LIGHT, Kana Miyake; Yuka Kobayashi; Keiko Morimoto; Akira Takamata, 2009, 59, 333, 333, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, PEAK OXYGEN UPTAKE DOES NOT CORRELATE WITH BLOOD VOLUME IN PERSONS WITH CERVICAL SPINAL CORD INJURY, Tomoyuki Ito; Yukiharu Higuchi; Yumi Koike; Kazunobu Okazaki; Sumiko Shiba; Takahiro Miyake; Hiroyasu Uenishi; Akira Takamata; Hiromitsu Kimura; Fumihiro Tajima, 2009, 59, 455, 455, Summary international conference
  • Not Refereed, JOURNAL OF PHYSIOLOGICAL SCIENCES, SPRINGER TOKYO, ESTROGEN ATTENUATES RESPONSES OF FOOD INTAKE AND PERIFORNICAL OREXINERGIC NEURON'S ACTIVITY TO GLUCOPRIVATION, Akira Takamata; Kana Miyake; Yoko Fujita; Yuko Nakamura; Yuka Kobayashi; Keiko Morimoto, 2009, 59, 458, 458, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Effect of estrogen replacement on food intake and hypothalamic c-Fos expression in ovariectomized rats, A Takamata; Y Saito; R Kobayashi; K Torii; K Morimoto, Mar. 2005, 19, 5, A1647, A1647, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Effect of estrogen replacement on water intake and hypothalamic c-Fos expression induced by plasma hyperosmolality or central angiotensin II in ovariectomized rats, K Torii; Y Kitamura; K Morimoto; A Takamata, Mar. 2005, 19, 5, A1647, A1648, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Cardiovascular and ventilatory responses during and after exercise in persons with cervical spinal cord injuries, T Ito; Y Higuchi; H Banno; T Mizushima; A Takamata; H Kimura; F Tajima, Mar. 2003, 17, 5, A941, A941, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Relationship between osmotic inhibition of thermoregulatory responses and sweat sodium concentration., A Takamata; T Yoshida; T Morimoto, Mar. 2000, 14, 4, A321, A321, Summary international conference
  • Not Refereed, ANESTHESIOLOGY, LIPPINCOTT WILLIAMS & WILKINS, Cardiopulmonary baroreceptor modulation of perioperative hypothermia, Y Nakajima; T Mizobe; K Hayashi; Y Kitamura; K Shigemi; A Takamata; Y Tanaka, Sep. 1998, 89, 3A, U296, U296, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Effect of heat acclimation on body fluid regulation in older subjects., A Takamata; T Ito; K Yaegashi; H Takamiya; Y Maegawa; T Itoh; T Morimoto; JE Greenleaf, Mar. 1998, 12, 4, A125, A125, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, Effect of plasma osmolality on thermoregulatory responses to passive heating in humans, A Takamata; K Nagashima; H Nose; T Morimoto, Mar. 1996, 10, 3, 681, 681, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, BODY-TEMPERATURE INFLUENCE ON OSMOTICALLY INDUCED VASOPRESSIN SECRETION IN HUMANS, GW MACK; A TAKAMATA; NS STACHENFELD; ER NADEL, Mar. 1995, 9, 4, A632, A632, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, ACUTE RECOVERY OF OSMOTICALLY INHIBITED SWEATING IN HUMANS BY DRINKING, A TAKAMATA; GW MACK; CM GILLEN; AC JOZSI; ER NADEL, Mar. 1994, 8, 4, A65, A65, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, FLUID REGULATION DURING EXTREME CELL DEHYDRATION IN OLDER ADULTS, N STACHENFELD; G MACK; A TAKAMATA; L DIPIETRO; E NADEL, Mar. 1994, 8, 5, A588, A588, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, BIPHASIC THIRST RESPONSE IN HUMANS FOLLOWING THERMAL EXERCISE SWEATING WITHOUT SODIUM REPLENISHMENT, A TAKAMATA; GW MACK; CM GILLEN; ER NADEL, Feb. 1993, 7, 3, A444, A444, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, MEASUREMENT OF PLASMA-VOLUME IN RATS USING FLUORESCENT-LABELED ALBUMIN MOLECULES, CM GILLEN; A TAKAMATA; GW MACK; ER NADEL, Feb. 1993, 7, 3, A444, A444, Summary international conference
  • Not Refereed, FASEB JOURNAL, FEDERATION AMER SOC EXP BIOL, CHANGE IN RIGHT ATRIAL PRESSURE DURING EXERCISE AND THE EFFECT ON THERMAL AND CIRCULATORY REGULATIONS, H NOSE; A TAKAMATA; G MACK; Y ODA; S HASHIMOTO; M HIROSE; E CHIHARA; T MORIMOTO, Mar. 1991, 5, 5, A1400, A1400, Summary international conference
  • Human sciences research, Kobe University, Interrelationship between osmoregulation and thermoregulation : Effect of physical training, heat acclimation and aging(Project of Environment Study for Supporting Development of Aged People(3)), Takamata Akira, Nov. 2002, 10, 1, 141, 158
  • 体力科學, 日本体力医学会, 166.高齢者の暑熱順化による水分出納および口渇感の変化, 岡山 寧子; 木村 みさか; 鷹股 亮; 伊藤 倫之; 永井 由香; 森本 武利, 01 Dec. 2000, 49, 6, 749, 749
  • 体力科學, 日本体力医学会, 358.血漿浸透圧上昇による体温調節反応の抑制と汗ナトリウム濃度との関係, 鷹股 亮; 森本 武利, 01 Dec. 1998, 47, 6, 881, 881
  • 体力科學, 日本体力医学会, 604.運動時の皮膚血管拡張反応における血漿浸透圧の役割, 鷹股 亮; 森本 武利; 能勢 博, 01 Dec. 1997, 46, 6, 914, 914
  • 体力科學, 日本体力医学会, 251.温熱性皮膚血管拡張閾値に対する血漿浸透圧の影響, 鷹股 亮; 能勢 博; 芳田 哲也; 森本 武利, 01 Dec. 1995, 44, 6, 732, 732
  • Japanese Journal of Physical Fitness and Sports Medicine, The Japanese Society of Physical Fitness and Sport Medicine, Role of central venous pressure on circulatory adjustment to hyperthermia, Takamata Akira; Nose Hiroshi; Morimoto Taketoshi, 01 Dec. 1989, 38, 6, 305, 305
  • Japanese Journal of Physical Fitness and Sports Medicine, The Japanese Society of Physical Fitness and Sport Medicine, TEMPERATURE DEPENCE OF SWIMMING EXERCISE-INDUCED CHANGES IN ETHANOL METABOLISM AND THERMOREGULATORY RESPONSES IN RATS, TAKAMATA Akira; TACHIYASHIKI Kaoru; IMAIZUMI Kazuhiko, 01 Dec. 1990, 39, 6, 804, 804
  • Japanese Journal of Physical Fitness and Sports Medicine, The Japanese Society of Physical Fitness and Sport Medicine, Water and electrolyte balance in the vascular space during graded exercise in humans, NOSE HIROSHI; TAKAMATA AKIRA; Gary W Mack; ODA YSHINOBU; OKUNO TADASHI; KANG DUK-HO; MORIMOTO TAKETOSHI, 01 Dec. 1990, 39, 6, 792, 792
  • 体力科學, 日本体力医学会, 139.血圧調節に血漿浸透圧、体温が及ぼす影響(【呼吸・循環】), 伊藤 倫之; 鷹股 亮, 01 Dec. 2001, 50, 6, 802, 802
  • 日本生気象学会雑誌, 唐辛子湯が下腿温浴時の体温および発汗に及ぼす影響, 鷹股 亮; 西田 直子; 森本 武利, 29 Jan. 1999, 35, 3, S69
  • 体力科學, 日本体力医学会, 156.灌流圧低下が運動時の骨格筋血流に及ぼす影響(呼吸・循環,一般口演,第60回 日本体力医学会大会), 川本 麻理子; 森本 恵子; 鷹股 亮, 01 Dec. 2005, 54, 6, 496, 496
  • 体力科學, 日本体力医学会, 155.精神性ストレス及び運動負荷時の昇圧反応に及ぼす月経周期や閉経の影響(呼吸・循環,一般口演,第60回 日本体力医学会大会), 森本 恵子; 森川 真悠子; 鷹股 亮, 01 Dec. 2005, 54, 6, 496, 496
  • 体力科學, 日本体力医学会, 188.エストロゲン補充が卵巣摘出ラットの摂取行動、活動量、体温の日内リズムに及ぼす影響(体液・内分泌,一般口演,第60回 日本体力医学会大会), 鷹股 亮; 川本 麻理子; 森本 恵子, 01 Dec. 2005, 54, 6, 512, 512
  • 長崎大学熱帯医学研究所共同研究報告集, 長崎大学, 血液浸透圧と体温調節反応:汗ナトリウム濃度との関連, 鷹股 亮; 森本 武利, Jul. 1998, 9, 118, 118
  • 体力科學, 日本体力医学会, 160. 静的運動時の骨格筋血流調節における性差、性周期の影響(呼吸・循環, 第61回 日本体力医学会大会), 鷹股 亮; 川本 麻理子; 森本 恵子, 01 Dec. 2006, 55, 6, 658, 658

Books etc

  • 9784764412194
  • ニュー運動生理学, 真興交易(株)医書出版部, 2015, Not Refereed
  • からだと温度の事典 脱水時の体温調節, 朝倉書店, 2010, Not Refereed
  • からだと温度の事典 運動時の体液調節, 朝倉書店, 2010, Not Refereed
  • 運動生理学のニューエビデンス, 真興交易社, 2010, Not Refereed
  • 身体トレーニング 運動生理学からみた身体機能の維持・向上 運動時の体液変化とその循環・体温調節への影響, 真興交易(株)医書出版部, 2009, Not Refereed
  • 環境生理学, 北海道大学出版会, 2007, Not Refereed
  • Environmental Physiology, 2007, Not Refereed
  • 人間の許容限界事典 14.体液, 朝倉書店, 2005, Not Refereed
  • 人間の許容限界事典 15.浸透圧, 朝倉書店, 2005, Not Refereed
  • 体温―運動時の体温調節システムとそれを修飾する因子― 体温調節システムと浸透圧調節, ナップ, 2002, Not Refereed
  • 最新栄養学第8版―専門領域の最新情報ー Chapter 11 水分・電解質バランスー体温調節および高温環境下での身体運動に及ぼす影響, 2002, Not Refereed
  • Merits of diluted sweat with training on arterial pressure and body temperature regulation in heat stress. In: Thermotherapy for Neoplasia, Inflammation, and Pain., Springer-Verlag, Tokyo, 2001, Not Refereed
  • 運動とホルモン 体液調節と液性因子, ナップ, 2001, Not Refereed
  • 新運動生理学(下巻) 環境と体液, 真興交易, 2001, Not Refereed
  • Merits of diluted sweat with training on arterial pressure and body temperature regulation in heat stress. In: Thermotherapy for Neoplasia, Inflammation, and Pain., Springer-Verlag, Tokyo, 2001, Not Refereed
  • Interrelationship between osmoregulation and thermoregulation in a hot engvironment and during exercise. In: Exercise, Nutrition, and Environmental Stress., Cooper Publishing Group, LLC, Camel, IN, 2000, Not Refereed
  • Interrelationship between osmoregulation and thermoregulation in a hot engvironment and during exercise. In: Exercise, Nutrition, and Environmental Stress., Cooper Publishing Group, LLC, Camel, IN, 2000, Not Refereed
  • スポーツ医科学 運動・スポーツと体内における反応 体液・血液の働き, 杏林書院, 1999, Not Refereed
  • Body fluid osmolality, blood volume and thermoregulation. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • The role of plasma osmolality in exercise-induced inhibition of cutaneous vasodilation. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • Effects of hypovolemia and hyperosmolality on cardiovascular responses to heat in awake rats.. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • Near infrared spectrophotometric monitoring of rhythmic fluctuation in oxygenated hemoglobin and myoglobin during muscular exercise. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • Body fluid osmolality, blood volume and thermoregulation. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • The role of plasma osmolality in exercise-induced inhibition of cutaneous vasodilation. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • Effects of hypovolemia and hyperosmolality on cardiovascular responses to heat in awake rats.. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • Near infrared spectrophotometric monitoring of rhythmic fluctuation in oxygenated hemoglobin and myoglobin during muscular exercise. In: The 1997 Nagano Symposium on Sports Sciences., Cooper Publishing Group, LLC, Carmel, IN, 1998, Not Refereed
  • Osmotic inhibition of thermally induced cutatneous vasodilation in humans and its role in the inhibition of cutaneous vasodilation during exercise. In: Thermal Physiology 1997. Proceedings of the International Symposium on Thermal Physiology., The August Krogh Institute, Copenhagen, 1997, Not Refereed
  • Osmotic inhibition of thermally induced cutatneous vasodilation in humans and its role in the inhibition of cutaneous vasodilation during exercise. In: Thermal Physiology 1997. Proceedings of the International Symposium on Thermal Physiology., The August Krogh Institute, Copenhagen, 1997, Not Refereed
  • Central venous pressure and cardiovascular responses to hyperthermia. In Temperature Regulation: Advances in Pharmacological Sciences, Birk-hauser Verlag, Basel, 1996, Not Refereed
  • Cardiovascular response to exercise in a hot environment. In Physiological Basis of Occupational Health: Stressful Environment. Progress in Biometeorology vol. 11., SPB Academic Publishing bv, Amsterdam, The Netherlands, 1996, Not Refereed
  • Central venous pressure and cardiovascular responses to hyperthermia. In Temperature Regulation: Advances in Pharmacological Sciences, Birk-hauser Verlag, Basel, 1996, Not Refereed
  • Cardiovascular response to exercise in a hot environment. In Physiological Basis of Occupational Health: Stressful Environment. Progress in Biometeorology vol. 11., SPB Academic Publishing bv, Amsterdam, The Netherlands, 1996, Not Refereed
  • Central venous pressure and cardiovascular responses to hyperthermia. In Temperature Regulation: Advances in Pharmacological Sciences, Birk-hauser Verlag, Basel, 1994, Not Refereed
  • Central venous pressure and cardiovascular responses to hyperthermia. In Temperature Regulation: Advances in Pharmacological Sciences, Birk-hauser Verlag, Basel, 1994, Not Refereed
  • Thirst, Exercise and Thermoregulation: Interrelationships. In Perspective in Exercise Science and Sports Medicine Volume 6, Exercise, Heat and Thermoregulation, Benchmark Press, Carmel, IN, 1993, Not Refereed
  • Thirst, Exercise and Thermoregulation: Interrelationships. In Perspective in Exercise Science and Sports Medicine Volume 6, Exercise, Heat and Thermoregulation, Benchmark Press, Carmel, IN, 1993, Not Refereed
  • Effect of heat load on body fluid and circulation. In: Hyperthermic Oncology in Japan '91, Shinohara, 1992, Not Refereed
  • Effect of heat load on body fluid and circulation. In: Hyperthermic Oncology in Japan '91, Shinohara, 1992, Not Refereed
  • 体温の「なぜ?」がわかる生理学 〜からだで感じる・考える・理解する〜, 杏林書院, 26 脱水症と体温の密接な関係とは, Apr. 2021
  • 解剖生理学 : 人体の構造と機能, 講談社, 河田, 光博; 三木, 健寿; 鷹股, 亮, Jan. 2020, ix, 179p, 9784065166352, cinii_books

Presentations

  • Oral presentation, 28 Nov. 2020, 29 Nov. 2020
  • Nominated symposium, 28 Nov. 2020, Dec. 2201

Works

  • 自律神経系中枢のMRIによる研究, 2005, 2005
  • マンガン造影を用いた、容量刺激、血圧変化に対する延髄および視床下部神経活動の解析, 2004, 2004
  • マンガン造影による浸透圧、容量刺激に対する視床下部神経核活動の解析, 2003, 2003
  • 経口補液飲料のナトリウム濃度が温熱脱水からの体液量回復に及ぼす影響, Feb. 2002, Mar. 2002
  • マイクロイメージング法による脳室周囲器官群および関連する視床下部・延髄の研究, 2002, 2002
  • T1緩和時間MRI法によるラット脳室周囲器官の測定, 2001, 2001

Awards

  • 久野寧記念賞, 1999, Japan

Research Projects

  • 基盤研究(C), 01 Apr. 2020, 31 Mar. 2023, 20K11604, エストロゲンによる快楽性糖摂取行動促進作用のメカニズムと恒常性摂食調節との連関, 鷹股 亮; 森本 恵子, 日本学術振興会, 科学研究費助成事業 基盤研究(C), 奈良女子大学, 4290000, 3300000, 990000
  • 基盤研究(C), 01 Apr. 2018, 31 Mar. 2021, 18K10991, 女性のライフステージによる女性ホルモン変動が脂質嗜好性に及ぼす影響とその作用機序, 森本 恵子; 鷹股 亮; 内田 有希, 日本学術振興会, 科学研究費助成事業 基盤研究(C), 奈良女子大学, 4290000, 3300000, 990000, 2019年度は、若年女性9名と若年男性11名を対象として、口腔内脂肪酸感受性・脂質嗜好性・脂質摂取量を測定し、唾液の口腔由来細胞の脂肪酸受容体mRNA発現について検討した。2018年度と2019年度を合わせた若年女性20名と男性24名の測定結果について、性差や女性の月経周期性変化を評価した。一方、動物実験では、雌性ラットにおけるエストラジオ―ル(E2)の脂質摂取量への作用だけでなく、プロゲステロン(Pro)の作用およびE2とProの併用が脂質摂取量に与える影響についても検討を加えた。また、慢性の社会的心理ストレス(chronic psychosocial stress:CPS)下での雌性ラットの摂食及び体重変化にE2が影響を与える可能性について検討を開始した。 (1)口腔内オレイン酸感受性に性差はないことが確認された。また、若年女性では排卵前期にオレイン酸感受性が高いという月経周期依存性変化があることが判明した。一方、脂肪嗜好性には月経周期性変化は見られず、オレイン酸感受性との間にも明確な関連は認められなかった。しかし、舌への脂肪刺激後にはオレイン酸感受性と脂肪嗜好性との間に相関関係が見られた。なお、血漿エストロゲン・プロゲステロン濃度と脂肪嗜好性との関には相関関係は認められなかった。 (2)閉経モデルである卵巣摘出(OVX)ラットへのPro補充は経時的な高脂肪食摂取量や体重増加量に影響を与えなかった。一方、絶食後の高脂肪食摂取量はE2補充群では抑制されたが、Pro補充群やE2・Pro併用補充群では抑制されなかった。したがって、Proは長期の摂食調節には関与しないものの、短期的にはE2の摂食抑制作用を阻害する可能性が示唆された。また、OVXラットにおけるCPS下のエネルギー摂取量および体重増加量の減少をE2補充は抑制するとの結果を得た。
  • Grant-in-Aid for Scientific Research (B), 01 Apr. 2016, 31 Mar. 2020, 16H03026, Mechanism for the environmental light-induced, Takamata Akira, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Nara Women's University, 17420000, 13400000, 4020000, Estrogen deficiency induced hyperphagia/obesity and increased depression-like behavior, which is possibly cause by the attenuated photosensitivity, and consequently the diminished biological rhythm regulation. At least some of these symptoms were reversed by exposure to high-intensity light during the light phase or adjusting diurnal feeding patterns in estrogen-deficiency rats. In addition, it has been shown that hyperphagia/obesity and increased depression-like behavior due to estrogen deficiency may be cased by a declined serotonergic function, and the antidepressant fluoxetine may improve these health disorders., url
  • Grant-in-Aid for Challenging Exploratory Research, 01 Apr. 2015, 31 Mar. 2017, 15K12355, Development of countermeasure against postmenopausal hyperphagia and obesity by controlling light environment and feeding rhythm pattern., Takamata Akira, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research, Nara Women's University, 3640000, 2800000, 840000, Hyperphagia and obesity induced by estrogen (E2) deficiency accompanies disorder of circadian feeding rhythm. We have shown that E2 regulates food intake in light dependent manner. In this study, we investigated whether E2 deficiency-induced hyperphagia and obesity can be attenuated by adjusting light environment and feeding rhythm. We found that E2 deficiency could weaken light-induced suppression of feeding and obesity. In addition, high intensity light stimulus suppressed food intake and body weight gain even in the E2 deficient state. We also found that forced feeding rhythm formation attenuated hyperphagia and obesity even in the E2 deficient state. Thus, appropriate lifestyle considering the light environment and feeding rhythm could be a countermeasure against postmenopausal hyperphagia and obesity., url
  • Grant-in-Aid for Scientific Research (C), 01 Apr. 2014, 31 Mar. 2017, 26350118, Study of functional foods as incretin effects for metabolic syndrome, Negishi Hiroko, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Mukogawa Women's University, 4810000, 3700000, 1110000, SHRSP.Z-Lepr fa /IzmDmcr rats (SPZF) show hypertension, hyperphagia, obesity, dyslipidemia, and insulin resistance. Many reports have suggested that glucagon-like peptide-1 (GLP-1) and dipeptidyl peptidase-4 (DPP-4) affect various organs. We observed the expression of GLP-1 and DPP-4 in SPZF rats.In this study, we have shown the effects of incretin may relate to the phenotype in metabolic syndrome status in SPZF. There are many reports that natural products have numerous health benefits, including protection against cardiovascular disease. Treatment with sake lees significantly increased the GLP-1 receptor expression than in control. Serum active GLP-1 level in peptide fraction of sake lees group was significantly increased than in control. Sake lees attenuated the development of renal damage through GLP-1 and antioxidant activities in SHRSP. Further studies are needed in order to clarify the effects of the fuctional foods through the incretin, url
  • Grant-in-Aid for Scientific Research (C), 01 Apr. 2012, 31 Mar. 2015, 24500975, Involvement of circadian feeding rhythm regulation in the mechanism for estrogen-induced hypophagia, TAKAMATA AKIRA, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Nara Women's University, 5200000, 4000000, 1200000, Estrogen attenuates food intake and enhances c-Fos expression in the suprachiasmatic nucleus specifically during the light phase. In the present study, we found that light exposure during the light phase is required to elicit an anorectic effect of estrogen. We also found that estrogen attenuates food intake and orexin A neuron’s responses to reduced glucose availability, which was possibly mediated by serotonergic neurons. Thus, estrogen enhances serotonergic neurons response to light, and the serotonergic neurons attenuate orexin-A neuron’s activity, which is, at least in part, a mechanism for the estrogen-induced hypophagia., url
  • Grant-in-Aid for Scientific Research (B), 01 Apr. 2011, 31 Mar. 2014, 23300275, The suppressive effects of estrogen on stress-induced cardiovascular responses in female and complementary nutrients for postmenopausal women, MORIMOTO Keiko; KOJO Shosuke; TAKAMATA Akira; NEGISHI Hiroko; YOSHIDA Ken-ichi; YANO Shigenobu, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Nara Women's University, 17940000, 13800000, 4140000, Menopause or mental stress is a risk factor for cardiovascular events. We examined the mechanisms accounting for suppressive effects of estrogen on stress-induced cardiovascular responses in ovariectomized (OVX) rats and complementary nutrients for postmenopausal women. In animal model, estrogen replacement attenuated pressor response to the cage-switch stress by suppressing the renin-angiotensin system in OVX rats. However, Kudzu root extracts had no effects on the stress-induced pressor responses in OVX rats. In human experiments, mental stress evoked by the Color Word Test induced the elevation in the vascular resistance of brachial artery in postmenopausal women compared with middle-aged premenopausal women. In addition, basal endothelial function was impaired in postmenopausal women compared with premenopausal women. However, the oral pretreatment of vitamin C restored these impairments in the postmenopausal women., url
  • Grant-in-Aid for Scientific Research (C), 2008, 2010, 20590230, Mechanisms of inhibitory effects of estrogens on psychological stress-induced pressor response via suppression of oxidative stress, MORIMOTO Keiko; TAKAMATA Akira; UEYAMA Takashi; KIMURA Hiroko; YOSHIDA KenーIchi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Nara Women's University, 4940000, 3800000, 1140000, The findings of experiments with volunteers or ovariectomized rats suggested that the menopause enhanced forearm vascular resistance to mental stress, and estrogen replacement attenuated pressor responses through its anti-oxidative activity., url
  • Grant-in-Aid for Scientific Research (C), 2005, 2006, 17590202, Mechanisms responsible for the attenuating effects of estrogen on cardiovascular responses to psychological stress in the central nervous system and the peripheral vessels, MORIMOTO Keiko; TAKAMATA Akira; UEYAMA Takashi; KIMURA Hiroko; YOSHIDA Ken-ichi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Nara Women's University, 3600000, 3600000, (1) Sex difference in norepinephrine surge in response to psychological stress through nitric oxide in rats A mild psychological stress induced by a cage-switch evoked a norepinephrine surge in the male, but not in the female rats. There was a sex difference in the norepinephrine surge in response to psychological stress through nitric oxide (NO), in association with pressor response. (2) Effects of estrogen on plasma catecholamine, NO metabolites (NOx) and 4-hydroxy-2-nonena1 during cage-switch stress Estrogen replacement tended to suppress plasma norepinephrine elevation induced by the stress in ovariectomized rat. Additionally, the NO synthase (NOS) inhibitor decreased this effect of estrogen. By Western blotting analysis, estrogen replacement enhanced basal endothelial NOS expression in mesenteries. Furthermore, estrogen replacement attenuated a basal level of plasma 4-hydroxy-2-nonenal, a marker for oxidative stress, and tended to enhance plasma NOx level. Our results suggest that estrogen attenuates the stress-induced pressor response by suppressing oxidative stress and enhancing NO bioavailability (3) Effects of estrogen replacement on neuronal activation induced by cage-switch stress in ovariectomized rat brain The stress-induced elevations in c-Fos expressions, a marker for neuronal activation, were detected in the following brain areas : lateral septal nucleus, paraventricular hypothalamic nucleus (PVN), dorsomedial hypothalamic nucleus (DMD), arcuate hypothalamic nucleus, paraventricular thalamic nucleus, and locus coeruleus (LC). Estrogen replacement suppressed stress-induced c-Fos expressions in PVN, DMD and LC. In addition, estrogen replacement enhanced the activation of NO-producing neurons in PVN. These findings suggest that estrogen replacement attenuates neuronal activation in these brain areas, at least partly by NO. These results suggest that estrogen replacement suppresses cardiovascular responses to psychological stress at least partly through its anti-oxidative effect on the periphery and through its inhibitory effect on neuronal activation in the brain of ovariectomized rats.
  • Grant-in-Aid for Scientific Research (C), 2004, 2005, 16590174, The central effect of estrogen on the regulation of food intake and osmoregulation., TAKAMATA Akira; MORIMOTO Keiko, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Nara Women's University, 3700000, 3700000, 1.Effect of estrogen replacement on food intake behavior in ovariectomized rats. Seven-week-old rats were ovariectomized and were assigned into estradiol- (E2-T) and placebo-treated (Pla-T) groups. The daily food intake and increase in body weight in the E2-T group were significantly lower than the Pla-T group. Food intake during both light and dark phases in the Pla-T group was larger than the E2-T group, and the difference between the two groups was more prominent during light phase. The number of c-Fos ir cells in suprachiasmatic nucleus (SCN) in the Pla-T group was not different from the E2-T group at the beginning of dark phase, but was lower than the E2-T group at the beginning of light phase. The c-Fos expressing cell number at the arcuate nucleus (ARC) in E2-T rats was lower than Pla-T rats in both light and dark phases. The responses of feeding and c-Fos expression at ARC were not different between the two groups. These results suggest that 1)estrogen tonically inhibits ARC neuronal activity and feeding, 2)estrogen might play a role in the production of circadian SCN neuronal activity rhythm and attenuation of feeding during light phase, and 3)estrogen modulates spontaneous feeding but does not influence fasting-induced feeding response. 2.Effect of estrogen replacement on osmoregulation in ovariectomized rats. To clarify the effect of estrogen on osmotically-induced water intake and its central mechanism, we examined the responses of water intake and hypothalamic neuronal activation (c-Fos expression) to plasma hyperosmolality and central angiotensin II (ANGII) administration. Ovariectomized rats were assigned into E2-T and Pla-T groups. Two weeks after the ovariectomy, rats were infused with hypertonic saline (1.5 M;0.33 ml/100g/BW ; i.v.). Access to water was provided 30-min after the infusion, and water intake was measured for 30 min. A few days later, we also examined c-Fos expression immunohistochemically. The same protocols were employed in other rats to examine the responses to central ANGII injection (5ng ; i.c.v.). E2-T rats drank significantly less amount of water than Pla-T rats in response to both hyperosmotic challenge and to central ANGII administration. The number of c-Fos ir cells in the OVLT in response to either osmotic or ANGII stimulations was not different between the E2- and Pla-T groups. The E2-T group showed lower number of c-Fos ir cells in the lateral part of the PVN after osmotic challenge compared to the Pla-T group. E2 treatment decreased AngII-induced c-Fos expression in the SFO and the SON as compared to Pla treatment. Thus, estrogen attenuates osmoregulatory water intake, and the site of this inhibitory action might be located on the pathway between the osmoreceptors and hypothalamic nuclei related to body fluid regulation. Central ANGII might be involved in the estrogen effect on osmoregulatory drinking.
  • Grant-in-Aid for Scientific Research (C), 2003, 2004, 15590208, The effect of estrogen on blood pressure regulation during psychological stress and its mechanism, MORIMOTO Keiko; TAKAMATA Akira; YOSHIDA Ken-ichi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Nara Women's University, 3600000, 3600000, We obtained the following results on the effect of estrogen on stress-induced pressor responses and its mechanism. (1)Estrogen attenuates pressor responses induced by psychological stresses through endothelial nitric oxide synthase(eNOS) overexpression in rats. Pressor response to the cage-switch stress tended to be suppressed in the female (F) group compared with the male (M) group in free moving rats using the telemetry system. Furthermore, these responses to the cage-switch and restraint stresses were attenuated significantly in the ovariectomized estrogen-treated (E) group compared with the placebo-treated (P) group. However, pretreatment of NOS inhibitor diminished the difference of the stress-induced pressor response between the P and E groups. Moreover, the expression of eNOS in the mesentery enhanced significantly in the E group compared with the M and P groups. These results suggest that estrogen attenuates psychological stress-induced pressor responses and the mesenteric eNOS overexpression could explain the mechanism for its effect in rats. (2)Pressor response to mental stress varies during menstrual cycle depending on plasma estradiol levels in women. The resting blood pressure(BP) was not different between the menstrual (M) and the pre-ovulatory (O) phases of menstrual cycle in young women(YW). The elevations of systolic BP(SBP) and diastolic BP(DBF) induced by the Color Word Test(CWT) were slightly, but not significantly attenuated in O-phase compared with M-phase. In addition, the resting plasma norepinephrine(NE) was higher in O-phase, and its CWT-induced elevation tended to be attenuated in O-phase. Furthermore, the resting DBF was higher in postmenopausal women(PM) than YW. The significant and immediate elevation of DBP during the CWT was greater in PM than in YW and continued until about 15 min of the recovery period. These findings suggest that estrogen may attenuate the DBP elevations induced by the mental stress in women.
  • Grant-in-Aid for Scientific Research (C), 2002, 2003, 14570064, Interactive effect of osmoregulatory and volume regulatory stimuli on thermoregulation., TAKAMATA Akira; MORIMOTO Keiko, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Nara Women's University, 3500000, 3500000, To gain better insights into the interaction between fluid regulatory and thermoregulatory systems, we examined the effect of body fluid regulatory stimuli on thermoregulatory responses in human subjects. Upright posture reduced thermogenesis in response to body core cooling, compared with supine position. In contrast, upright posture enhanced peripheral vasoconstriction. Therefore, the thermoregulatory response to cold stress is influenced by volume regulatory system. The results also suggest that the mechanisms controlling peripheral vasoconstriction and thermogenesis during cold stress are appeared to be independent. We also examined the effect of plasma hyperosmolality on baroreceptor unloading-induced peripheral vasoconstriction. Plasma hyperosmolality augmented the reduction of forearm vascular conductance induced by lower body negative pressure during heat stress but not during normothermia. Therefore, there. apparently exists an interactive effect of plasma hyperosmolality and central hypovoloemia on the peripheral vascular response during heat stress, but not during normothermia. Our findings suggest that plasma hyperosmolality enhances baroreceptor-mediated reduction of thermal active peripheral vasodilation, but does not enhance the vasoconstrictor system. In a series of animal experiments, we examined the central mechanisms of the body fluid regulatory system. We quantified the permeability of capillaries in the subfornical organ of rat by a nuclear magnetic resonance method in combination with a venous injection of a relaxation reagent, Gd-DTPA^<2-> which could not pass through the blood-brain barrier (BBB). The proposed value may be 10-100 times larger than that of the blood-barrier in the cortex. We conclude that the capillaries in the SFO have one of the highest water permeability values among all of the capillaries in the brain, and this site may play an important role in osmoreception. In another animal experiment, we suggest that Mn^<2+> MRI is a useful technique for identifying in vivo the active brain region in the hypothalamus in response to various stimuli.
  • Grant-in-Aid for Scientific Research (C), 2002, 2003, 14571683, Basic study of the effects of environmental conditions on tear dynamics using an environmental chamber, YOKOI Norihiko; TAKAMATA Akira, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Kyoto Prefectural University of Medicine, 3500000, 3500000, Tears on soft contact lens (SCL) are very thin and this is thought to serve as a model system for the evaluation of the effect of environment on tears. Using an artificial chamber and this model system, we tried to examine the effect of environment on tears by evaluating tear dynamics and the symptom of dryness in contact lens wearers, under different temperature and humidity conditions. The results were that the thin tear film on the SCL got thinner and more unstable at a lower temperature and a lower humidity, the effect being more prominent at a lower temperature. Moreover, this tendency was found to depend on the water content of SCL and increases in SCLs with a higher water content. Also, the tear film on SCL is affected by the wind ; an increase in wind velocity was found to make the tear film on SCL thinner and more unstable, resulting in the production of a dry symptom.
  • Grant-in-Aid for Scientific Research (C), 2001, 2002, 13670047, Water permeability of capillaries in the subfornical organ of rats determined by Gd-DTPA^<2-> enhanced ^1H magnetic resonance imaging, SEO Yoshiteru; MURAKAMI Masataka; TAKAMATA Akira; ITOH Toshiyuki, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Kyoto Prefectural University of Medicine, 2900000, 2900000, The water permeability of capillaries in the subfomical organ (SFO) of rat was measured by a ^1H nuclear magnetic resonance method in combination with a venous injection of a relaxation reagent: gadolinium-diethylene triamine-N,N,N',N",N"-pentaacetic acid (Gd-DTPA^2), which could not pass through the blood-brain barrier (BBB). Judging from results of Gd-DTPA^2 dose dependency in the intact brain and the BBB permeabilized brain, Gd-DTPA^2 could not have leaked out from the capillaries in the cortex,thalamus or SFO, but it could have been extravasated in the posterior lobe of the pituitary gland. The longitudinal (T_1) relaxation time of water in the SFO region was measured by inversion-recovery magnetic resonance imaging at 4.7 T. The T_1 relaxation rates (1/T_1) before and after Gd-DTPA^2 infusion were 0.70 ^^+__-0.02s^<-1> (mean ^^+__- SEM, n=9) and 1.53 ^^+__- 0.11s^<-1> (n=9), respecitively. The rate constant for water influx to the capillaries was estimated to be 0.84 ^^+__- 0.11s^<-1> (n=9) which corresponds with a diffusive membrane permeability (Pd) of 3.7 x 10^<-3> cm s^<-1>. Compared with values found in the literature available on this subject, this Pd value of the capillaries in SFO was the same order as that of transmembrane permeability of water of the vasa recta, and it may be 10 - 100 times larger than that of the blood-brain barrier in the cortex. Areas of the cortex and thalamus showed minimal changes in T_1 relaxation rate (ca. 0.09s^<-1>), but these were not statistically significant, which corresponds to Pd values much smaller than that found in the SFO. From these results, we conclude that the capillaries in SFO have one of the highest water permeability values among all of the capillaries in SFO have one of the highest water permeability values among all of the capillaries in the brain. It is also suggested that this magnetic resonance imaging, based on T_1 relaxation rate, is a useful method to detect local water permeability in situ
  • Grant-in-Aid for Scientific Research (C), 2000, 2001, 12670065, Interaction of stress defending system, thermoregulation and osmoregulation in the systemic vasopressin release, TAKAMATA Akira; ITO Tomoyuki; ITOH Toshiyuki, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Kyoto Prefectural University of Medicine, 3200000, 3200000, To elucidate the interactive effect of thermal and stress stimuli and osmoregulation on systemic vasopressin secretion, we examined the effect of endotoxemia on vasopressin release and its mechanism in rats. We also examined the mechanism of vasopressin release during exercise in humans. Endotoxemia, induced by intravenous lipopolysaccharide (IPS) administration, induced vasopressin release and water ingestion behavior in rats without any changes in plasma osmolality or plasma volume. Intracerebroventricular (i. c. v.) administration of losartan (angiotensin II AT1 receptor antagonist) almost completely inhibited these responses, suggesting that the brain angiotensin II is involved in the LPS-induced systemic vasopressin secretion and thirst via AT1 receptor. To reveal the mechanism of vasopressin release during exercise in humans, we compared the relationship between plasma vasopressin concentration and plasma osmolality during a graded cycle ergo meter exercise protocol and this relationship during hyper tonic saline infusion at rest. Exercise at lower intensity (< 60 % maximal oxygen uptake (VO_2max)) attenuated osmotic vasopressin secretion, and exercise at higher intensity (> 60 % VO_2max) augmented osmotic vasopressin secretion. Blood pressure and heart rate increased with the increase in exercise intensity, and esophageal temperature, plasma lactate concentration, and plasma ACTH concentration increased above 60 % VO_2max. These responses did not occur during hyper tonic saline infusion. The results suggest that the attenuated osmotic vaspressin secretion at the lower exercise intensity might be due to the increased blood pressure, and that the augmented osmotic vasopressin secretion at the higher exercise intensity might be due to the increased body core temperature and/or stress-induced CRH secretion, CRH has been reported to stimulate vasopressin secretion in dogs. In addition, our results demonstrated that osmotic vasopressin secretion did not stimulate ACTH secretion from the anterior pituitary gland.
  • 奨励研究(A), 1998, 1999, 10770031, 浸透圧調節系の体温調節系・循環調節系に対する修飾機構の解析, 鷹股 亮, 日本学術振興会, 科学研究費助成事業 奨励研究(A), 京都府立医科大学, 1800000, 1800000, 1)ヒトにおいて、暑熱馴化により体液調節能が向上し、血漿浸透圧上昇による体温調節反応の抑制が減弱する。 温熱脱水(体重の約1.5-2.0%)後、被験者に水分の自由摂取を2時間にわたって行なわせた際の水分バランスをみると、暑熱馴化前では脱水量の約50%しか回復しないが、暑熱馴化(7日間)によりその回復は、約80%になり、暑熱馴化が体液調節機能を亢進させることが明らかになった。しかし、この体液調節機能の向上は、同様の暑熱馴化プログラムを行なった高齢者では認められなかった。従って、体液調節系と体温調節系の相互作用に加齢の影響があることが明らかになった。また、暑熱馴化は汗ナトリウム(Na)濃度を低下させることが知られている。汗Na濃度の低下は、発汗時の血漿浸透圧の上昇を増加させる。一方、我々は血漿浸透圧の上昇が体温上昇時の体温調節反応を抑制することを報告して来た。そこで、暑熱馴化が浸透圧上昇による体温調節機能の抑制作用が減弱させるのではないかという仮説を立て、実験を行った。その結果、浸透圧上昇に対する体温調節反応の抑制(発汗および皮膚血管拡張反応の深部体温閾値の上昇)は、汗Na濃度が低い被験者程小さくかった。従って、馴化している個人程浸透圧上昇による体温調節機能の抑制は小さくなることが明らかになった。 2)エンドトキシン血症時の飲水およびバゾプレッシン分泌に脳内アンギオテンシンIIが関与する エンドトキシン血症時には、体温上昇がおこるが血中のバゾプレッシン濃度の上昇および飲水行動が起こる。血漿浸透圧上昇時のバゾプレッシン分泌および飲水は脳内アンギオテンシンIIをブロックすることによって抑制できるが、LPS投与してエンドトキシン血症にしたラットにみられるバゾプレッシン分泌および飲水も脳内アンギオテンシンIIをブロックすることによって抑制できた。体温調節系と浸透圧調節系の相互作用に脳内アンギオテンシンが関与している可能性が示唆された。
  • Grant-in-Aid for Scientific Research (B), 1997, 1998, 09470017, Adaptability of older adults to heat with reference to water balance, MORIMOTO Taketoshi; YAEGASHI Kazuhiro; TAKAMATA Akira; ITOH Toshiyuki, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Kyoto Prefectural University of Medicine, 10700000, 10700000, Adaptability of older adults to heat stress was assessed in relation to water balance. 1. Changes in water balance with heat acclimation in older adults Nine oIder and 6 younger adlts were exposed to heat-exercise stress for 8 days, and regulatory responses in body temperature and water balance were compared on the first and 8th day. The results obtained shown lower body fluid volumes, higher losses of water and salts, lower water intake due to the lack of thirst, lower responsiveness of water related hormones, and lesser acclimation to heat in older subject. It is suggested that these factors are relevant to the higher incidences of heat casualty in the elderly (submitted to American Journal of Physiology). 2. Epidemiology of heat stroke Based on the National Death Statistics between 1968 and 1994, the epidemiology of heat stroke death was analyzed. About 150 deaths have been reported in the years with heat waves in Japan, while 589 cases were reported in 1994 with sever heat waves. Out of the heat stroke death, 64% were found in the elderly people (submitted to International Journal of Biometeorology). 3. The effects of dehydration on body temperature regulation The experimental results from our laboratory on the effects of dehydration on body temperature regulation were reviewed dividing the effect of hypovolemia (Progress in Brain Research, Vol. 115, Brain Function Hot Environment) and hyperosmolality (Reviews in Clinical & Basic Pharmacology). The experimental findings obtained in this projects suggests that the high incidences of heat casualty in the elderly are related to the lower level of water balance in older subjects.
  • 奨励研究(A), 1996, 1996, 08770049, 浸透圧調節系に対する体温調節系からの修飾機構とその生理的意義のの解析, 鷹股 亮, 日本学術振興会, 科学研究費助成事業 奨励研究(A), 京都府立医科大学, 1000000, 1000000, 体温調節系と浸透圧調節系は密接に関連しあって機能している。我々はヒトにおいて体温の上昇が浸透圧調節系の機能を浸透圧依存性に亢進させることを明らかにしてきたが、ラットを用いた実験モデルを作成してそのメカニズムを更に明らかにすることを目的とした。 ラットを用いた実験モデルを作成するにあたって、先ずラットの浸透圧刺激性飲水パターンを明らかにするための実験を行った。ラットの側脳室内に高張性の人工髄液を持続注入して飲水量を測定した。また、容量刺激による飲水のパターンと浸透圧刺激性の飲水パターンを比較するため、利尿剤であるfurosemideを投与した際のラットの飲水量も測定した。浸透圧刺激は直ちに飲水を惹き起こしたのに対し、容量調節系の飲水の発現は、浸透圧刺激性の飲水に比べて有意に遅れ、更に長時間にわたって持続することが明らかとなった。この実験よりラットの飲水パターンは、イヌ等の動物と比べヒトのそれに近く、実験のモデル動物として妥当であることが明らかになった。しかし、ラットは、浸透圧刺激によりナトリウム利尿が起こって浸透圧調節に働く点はヒトとは異なる反応を示した。 体温上昇の浸透圧刺激飲水に対する影響を明らかにするためにラットに浸透圧刺激を加えた後の飲水量を高温環環境下(32℃)とラットにおける中性温度域である24℃の環境温下で比較した。室温32℃の環境下でラットの体温は、0.5℃から1℃上昇し、飲水量は体温の上昇により約30%低下した。この結果は、ヒトにおける反応とは異なった。体温の上昇によりラットの行動量が低下したことが飲水行動の抑制を惹き起こしたものと考えられる。現在、血漿バゾプレッシング濃度の測定を行っており、血漿バゾプレッシングの反応よりラットにおける体温上昇による飲水量の低下が、浸透圧調節系に対する抑制なのか行動の抑制であるのかが明らかになると期待される。また、ラットの体温の上昇を環境温の上昇にではなく、thermodeを用いて上昇させる実験も計画中である。
  • 一般研究(C), 1995, 1995, 07670091, 脳内浸透圧受容システムの暑熱脱水時血圧調節における生理的役割, 能勢 博; 鷹股 亮, 日本学術振興会, 科学研究費助成事業 一般研究(C), 信州大学, 2200000, 2200000, 発汗による血漿浸透圧の上昇は発汗と皮膚血管拡張の抑制を引き起こし熱放散を減少させる。温熱脱水時の脳脊髄液の浸透圧上昇が血圧調節に与える影響を検討する目的で、脱水したラットの側脳室内に低張性人口髄液を注入して側脳室内のNa濃度([Na]_)を脱水前の値に回復させた場合の動脈血圧および心拍出量を連続測定した。その結果、[Na]_の低下に比例して動脈血圧、心拍出量は低下した。これらの結果は温熱脱水による[Na]_の上昇は低血液量に起因する低血圧を防止する上で重要な入力信号であることを意味する。次に高[Na]_の高体温時の皮膚血管への影響を検討する目的で、ラットの側脳室内に高張性人口髄液を注入したときの平均動脈血圧(MAP)、中心静脈圧、尾動脈血流量(CBF)を連続測定した。尾動脈の血管コンダクタンス(CVC)はCBF/MAPで算出した。赤外線ランプによって食道温を37℃から40℃まで上昇させると、CBFは2.3±0.4ml/min(平均値±標準誤差,n=14)から3.2±0.4ml/minに上昇した(p<0.001)。一方、MAPは125±5mmHgから95±5mmHgに低下し(p<0.01)、CVCは0.019±0.003から0.034±0.004ml/(min mmHg)に上昇した。 MAPとCVCの間に高い逆相関関係が観察された(r=-0.94,p<0.001)。体温を40℃に上昇させたラットの側脳室内に高張性人口髄液を注入するとMAPおよびCVCは熱負荷の前の値にまで回復し、その際CVCとMAPの間に熱負荷と同様高い逆相関が観察され(r=-0.93,p<0.001)、回帰係数は熱負荷時とほぼ一致した。 以上の結果は体温上昇による尾部皮膚血管の拡張は末梢血管抵抗を低下させ動脈血圧の維持を困難にすること、さらに温熱脱水等による髄液浸透圧の上昇は高体温時の過度の皮膚血管拡張を抑制して血圧維持に働くことが明らかになった。
  • 奨励研究(A), 1995, 1995, 07770050, 高温環境下での蒸発性熱放散に対する脳室周囲器官浸透圧受容器からの修飾, 鷹股 亮, 日本学術振興会, 科学研究費助成事業 奨励研究(A), 京都府立医科大学, 1000000, 1000000, 脱水等による血漿浸透圧の上昇は,高温環境下での体温調節反応である発汗や蒸発性熱放散を抑制することが知られている。この浸透圧の体温調節反応抑制のメカニズムを明らかにすることを最終目的として実験を行った。 第一段階として浸透圧刺激が蒸発性熱放散を特異的に抑制するのか、それとも高温環境下での体温調節反応一般に抑制的に働くのかを明らかにすることを目的として、ヒトの皮膚血管拡張反応に対する血漿浸透圧上昇の影響を検討した。この実験ではさらに、血漿浸透圧上昇の皮膚血管拡張反応に対する影響を定量化するために、血漿浸透圧をいろいろ変化させて皮膚血管拡張がおこる閾値深部体温との関係を求めた。血漿浸透圧は,0.9%,2%,3%の食塩水を静脈内に輸液することによって変化させた。皮膚血管拡張開始の深部体温閾値は血漿浸透圧が上昇する程高温側にシフトし,その結果同じ温熱負荷にも関わらず浸透圧が高い程体温の上昇が大きくなった。この結果より、血漿浸透圧の上昇は、蒸発性熱放散のみならず皮膚血管拡張反応にも抑制作用があることが明らかとなった。即ち,浸透圧刺激が体温調節中枢に影響を及ぼしている可能性が示唆された。更に、その抑制の程度は血漿浸透圧が上昇するほど上昇することが明らかとなった。 現在ラットを用いた実験モデルを作成し実験を進行している。今後,浸透圧受容器から体温調節中枢に対する影響をラットのモデルでさらに明らかにしていく予定である。

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