研究者総覧

芝﨑 学SHIBASAKI Manabuシバサキ マナブ

所属部署名研究院工学系工学領域
職名教授
Last Updated :2022/10/06

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プロフィール情報

  • 芝﨑, シバサキ
  • 学, マナブ

学位

  • 博士(学術), 神戸大学
  • 修士(教育学), 神戸大学

研究分野

  • ライフサイエンス, 生理学
  • 人文・社会, 家政学、生活科学
  • ライフサイエンス, 体育、身体教育学
  • ライフサイエンス, 生体医工学

経歴

  • 2017年04月, 2021年03月, 奈良女子大学研究院生活環境科学系
  • 2012年04月, 2017年03月, 奈良女子大学研究院生活環境科学系准教授
  • 2009年04月, 2012年03月, 奈良女子大学大学院人間文化研究科准教授
  • 2008年03月, 2009年03月, 奈良女子大学生活環境学部生活健康・衣環境学科准教授
  • 2007年04月, 2008年02月, 奈良女子大学生活環境学部生活健康・衣環境学科助教
  • 1999年04月, 2007年03月, 奈良女子大学生活環境学部生活環境学科生活健康学講座助手
  • 2004年03月, 2005年03月, 在外研究(テキサス大学医学部ダラス校)
  • 1998年08月, 1999年03月, Institute for Exercise & Environmental Medicine, Presbyterian Hospital of Dallas, Research Associate
  • 1998年04月, 1999年03月, 日本学術振興会特別研究員
  • 2021年04月, 9999年, 奈良女子大学研究院工学系工学領域

学歴

  • 1995年04月, 1998年03月, 神戸大学, 自然科学研究科(学習院大学、甲南大学以外の大学), 知能科学
  • 1993年, 神戸大学, 教育学部, 初等教育

担当経験のある科目(授業)

  • パサージュ(37B), 奈良女子大学
  • 被服衛生学, 奈良女子大学
  • 環境生理学, 奈良女子大学
  • 温熱生理学演習, 奈良女子大学
  • 生活健康論Ⅱ, 奈良女子大学
  • 生体機能調節論演習, 奈良女子大学
  • 人体生理学実習, 奈良女子大学
  • 生活健康学概論, 奈良女子大学
  • 温熱生理学, 奈良女子大学
  • 生体機能調節論, 奈良女子大学
  • 健康づくり運動実習, 奈良女子大学
  • 被服生理学, 奈良女子大学
  • 心身健康学概論Ⅰ, 奈良女子大学
  • 正規活健康学基礎実習, 奈良女子大学

Ⅱ.研究活動実績

論文

  • 査読あり, 英語, PLos One., Modality differences in ERP components between somatosensory and auditory Go/No-go paradigms in prepubescent children., e0259653
  • 査読あり, 英語, PLos One, Effects of passive heat stress and recovery on human cognitive function: An ERP study., e0254769
  • 査読あり, 英語, The Journal of Physiological Sciences, An assessment of hypercapnia-induced elevations in regional cerebral perfusion during combined orthostatic and heat stresses, Manabu Shibasaki; Kohei Sato; Ai Hirasawa; Tomoko Sadamoto; Craig G. Crandall; Shigehiko Ogoh, We investigated that the effects of hypercapnia-induced elevations in cerebral perfusion during a heat stress on global cerebrovascular responses to an orthostatic challenge. Seven volunteers completed a progressive lower-body negative pressure (LBNP) challenge to presyncope during heat stress, with or without breathing a hypercapnic gas mixture. Administration of the hypercapnic gas mixture increased the partial pressure of end-tidal CO2 greater than pre-heat stress alone, and increased both internal carotid artery (ICA) and vertebral artery (VA) blood flows (P < 0.05). During LBNP, both ICA and VA blood flows with the hypercapnic gas mixture remained elevated relative to the control trial (P < 0.05). However, at the end of LBNP due to pre-syncopal symptoms, both ICA and VA blood flows decreased to similar levels between trials. These findings suggest that hypercapnia-induced cerebral vasodilation is insufficient to maintain cerebral perfusion at the end of LBNP due to pre-syncope in either the anterior or posterior vascular beds., 2020年05月, 70, 1, 25, 25, 研究論文(学術雑誌), 国内誌
  • 査読あり, 日本語, 繊維製品消費科学, 圧衝撃緩和性からみたゴールボール用プロテクター素材の検討, 坂下 理穂; 加藤 礼菜; 諸岡 晴美; 渡邊 敬子; 芝﨑 学, 2020年04月, 61, 4, 308, 316, 研究論文(学術雑誌)
  • 査読あり, 英語, NeuroReport, Differences in characteristics of somatosensory evoked potentials between children and adults, Miho Takezawa; Keita Kamijo; Manabu Shibasaki; Hiroki Nakata, The present study examined the characteristics of somatosensory processing in healthy prepubescent children (mean age: 124.9 ± 3.8 months) compared with young adults. Somatosensory evoked potentials at the frontal (Fz) and centroparietal (C3') electrodes were recorded by delivering an electrical stimulus to the right median nerve at a rate of 3 Hz. The characteristics of somatosensory evoked potential waveforms at C3' were markedly different between the two groups, while those at Fz were similar. Specifically, the waveforms at C3' in the children involved not only standard P12, N18, P22, N27, P45, and N60 components, but also additional positive (P3) and negative (N3) components between N27 and P45, which were not found in adults. The amplitude of P22 at C3' was significantly larger in the children than adults, indicating hyper-excitability/responsiveness of neural activity on somatosensory processing. In contrast, the amplitudes of N15 at Fz and N27 at C3' were smaller in the children than adults, suggesting an immature somatosensory system in the children. The peak latencies of P12, N15, and P18 at Fz, and P12 and N18 at C3' were significantly shorter in the children than adults, which was dependent on the height. These results indicate the developing somatosensory processing with hyper- and hypo-excitability of neural activity in prepubescent children., 2019年12月, 30, 18, 1284, 1288, 研究論文(学術雑誌), 国際誌
  • 査読あり, 日本語, 日本生気象学会雑誌, 認知機能と環境ストレス, 中田大貴; 芝﨑学, 2019年10月, 56, 1, 3, 11, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Effects of whole body skin cooling on human cognitive processing: a study using SEPs and ERPs, Hiroki Nakata; Fumino Kobayashi; Justin S. Lawley; Ryusuke Kakigi; Manabu Shibasaki, The present study investigated the effect of whole body skin cooling on somatosensory ascending processing by utilizing somatosensory-evoked potentials (SEPs) and motor execution, as well as inhibitory processing by event-related potentials (ERPs). Fourteen healthy participants wearing a water-perfused suit performed two sessions ( sessions 1 and 2) consisting of SEPs and ERPs with somatosensory Go/No-go paradigms under two conditions (cold stress and control) on different days. In session 2, under the cold stress condition, whole body skin cooling was achieved by circulating 20°C water through the suit for 40 min, whereas 34°C water was perfused in the other sessions. The mean skin temperature decreased from 35.0 ± 0.5°C ( session 1) to 30.4 ± 0.9°C ( session 2) during whole body skin cooling, but the internal temperature was maintained. Whole body skin cooling delayed the peak latencies of N20, P25, and P45 components at C4′ of SEPs (all: P < 0.05). Moreover, the peak latencies of P14, N18, and P22 components at Fz of SEPs and the Go-P300 component of ERPs were delayed (all: P < 0.05). In contrast, the peak amplitudes of all individual components of SEPs as well as N140 and P300 of ERPs remained unchanged. These results suggest that passive whole body skin cooling delays neural activities on somatosensory processing and higher cognitive function., 2019年09月01日, 317, 3, R432, R441, 研究論文(学術雑誌)
  • 査読あり, 英語, Physiological Reports, Effects of repetitive exercise and thermal stress on human cognitive processing, Manabu Shibasaki; Mari Namba; Yoshi-Ichiro Kamijo; Tomoyuki Ito; Ryusuke Kakigi; Hiroki Nakata, 2019年02月, 7, 4, e14003, e14003, 研究論文(学術雑誌)
  • 査読あり, 英語, International Journal of Hyperthermia, Differences in serum IL-6 response after 1 °C rise in core body temperature in individuals with spinal cord injury and cervical spinal cord injury during local heat stress, Takamasa Hashizaki; Yukihide Nishimura; Kenzo Teramura; Yasunori Umemoto; Manabu Shibasaki; C. A. Leicht; Ken Kouda; Fumihiro Tajima, 2018年12月31日, 35, 1, 541, 547, 研究論文(学術雑誌)
  • 査読あり, 英語, European Journal of Pain, Warm-, hot- and pain-related neural activities depending on baseline skin temperatures, H. Nakata; R. Kakigi; M. Shibasaki, 2018年11月, 22, 10, 1791, 1799, 研究論文(学術雑誌)
  • 査読無し, 日本語, 体育の科学, 暑熱環境下の循環調節とトレーニング適応, 芝﨑学, 2018年07月, 68, 7, 519, 525, 論文集(書籍)内論文
  • 査読あり, 英語, Journal of Applied Physiology, Dynamic cerebral autoregulation during cognitive task: effect of hypoxia, Shigehiko Ogoh; Hiroki Nakata; Tadayoshi Miyamoto; Damian Miles Bailey; Manabu Shibasaki, Changes in cerebral blood flow (CBF) subsequent to alterations in the partial pressures of oxygen and carbon dioxide can modify dynamic cerebral autoregulation (CA). While cognitive activity increases CBF, the extent to which it impacts CA remains to be established. In the present study we determined whether dynamic CA would decrease during a cognitive task and whether hypoxia would further compound impairment. Fourteen young healthy subjects performed a simple Go/No-go task during normoxia and hypoxia (inspired O2 fraction = 12%), and the corresponding relationship between mean arterial pressure (MAP) and mean middle cerebral artery blood velocity (MCA Vmean) was examined. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated with transfer function analysis. While MCA Vmean increased during the cognitive activity ( P < 0.001), hypoxia did not cause any additional changes ( P = 0.804 vs. normoxia). Cognitive performance was also unaffected by hypoxia (reaction time, P = 0.712; error, P = 0.653). A decrease in the very low- and low-frequency phase shift (VLF and LF; P = 0.021 and P = 0.01) and an increase in LF gain were observed ( P = 0.037) during cognitive activity, implying impaired dynamic CA. While hypoxia also increased VLF gain ( P < 0.001), it failed to cause any additional modifications in dynamic CA. Collectively, our findings suggest that dynamic CA is impaired during cognitive activity independent of altered systemic O2 availability, although we acknowledge the interpretive complications associated with additional competing, albeit undefined, inputs that could potentially distort the MAP-MCA Vmean relationship. NEW & NOTEWORTHY During normoxia, cognitive activity while increasing cerebral perfusion was shown to attenuate dynamic cerebral autoregulation (CA) yet failed to alter reaction time, thereby questioning its functional significance. No further changes were observed during hypoxia, suggesting that impaired dynamic CA occurs independently of altered systemic O2 availability. However, impaired dynamic CA may reflect a technical artifact, given the confounding influence of additional inputs that could potentially distort the mean arterial pressure-mean middle cerebral artery blood velocity relationship., 2018年06月01日, 124, 6, 1413, 1419, 研究論文(学術雑誌)
  • 査読あり, 英語, Spinal Cord, A comparison of static and dynamic cerebral autoregulation during mild whole-body cold stress in individuals with and without cervical spinal cord injury: a pilot study, Jan W. van der Scheer; Yoshi-Ichiro Kamijo; Christof A. Leicht; Philip J. Millar; Manabu Shibasaki; Victoria L. Goosey-Tolfrey; Fumihiro Tajima, 2018年05月, 56, 5, 469, 477, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Heart and Circulatory Physiology, Effect of increases in cardiac contractility on cerebral blood flow in humans, Shigehiko Ogoh; Gilbert Moralez; Takuro Washio; Satyam Sarma; Michinari Hieda; Steven A. Romero; Matthew N. Cramer; Manabu Shibasaki; Craig G. Crandall, The effect of acute increases in cardiac contractility on cerebral blood flow (CBF) remains unknown. We hypothesized that the external carotid artery (ECA) downstream vasculature modifies the direct influence of acute increases in heart rate and cardiac function on CBF regulation. Twelve healthy subjects received two infusions of dobutamine [first a low dose (5 μg·kg−1·min−1) and then a high dose (15 μg·kg−1·min−1)] for 12 min each. Cardiac output, blood flow through the internal carotid artery (ICA) and ECA, and echocardiographic measurements were performed during dobutamine infusions. Despite increases in cardiac contractility, cardiac output, and arterial pressure with dobutamine, ICA blood flow and conductance slightly decreased from resting baseline during both low- and high-dose infusions. In contrast, ECA blood flow and conductance increased appreciably during both low- and high-dose infusions. Greater ECA vascular conductance and corresponding increases in blood flow may protect overperfusion of intracranial cerebral arteries during enhanced cardiac contractility and associated increases in cardiac output and perfusion pressure. Importantly, these findings suggest that the acute increase of blood perfusion attributable to dobutamine administration does not cause cerebral overperfusion or an associated risk of cerebral vascular damage. NEW & NOTEWORTHY A dobutamine-induced increase in cardiac contractility did not increase internal carotid artery blood flow despite an increase in cardiac output and arterial blood pressure. In contrast, external carotid artery blood flow and conductance increased. This external cerebral blood flow response may assist with protecting from overperfusion of intracranial blood flow., 2017年12月01日, 313, 6, H1155, H1161, 研究論文(学術雑誌)
  • 査読あり, 英語, Journal of Applied Physiology, Effects of acute hypoxia on human cognitive processing: a study using ERPs and SEPs, Hiroki Nakata; Tadayoshi Miyamoto; Shigehiko Ogoh; Ryusuke Kakigi; Manabu Shibasaki, Although hypoxia has the potential to impair the cognitive function, the effects of acute hypoxia on the high-order brain function (executive and/or inhibitory processing) and somatosensory ascending processing remain unknown. We tested the hypothesis that acute hypoxia impairs both motor executive and inhibitory processing and somatosensory ascending processing. Fifteen healthy subjects performed two sessions ( sessions 1 and 2), consisting of electroencephalographic event-related potentials with somatosensory Go/No-go paradigms and somatosensory-evoked potentials (SEPs) under two conditions (hypoxia and normoxia) on different days. On 1 day, participants breathed room air in the first and second sessions of the experiment; on the other day, participants breathed room air in the first session, and 12% O2 in the second session. Acute hypoxia reduced the peak amplitudes of Go-P300 and No-go-P300, and delayed the peak latency of Go-P300. However, no significant differences were observed in the peak amplitude or latency of N140, behavioral data, or the amplitudes and latencies of individual SEP components between the two conditions. These results suggest that acute hypoxia impaired neural activity in motor executive and inhibitory processing, and delayed higher cognitive processing for motor execution, whereas neural activity in somatosensory processing was not affected by acute hypoxia. NEW & NOTEWORTHY Hypoxia has the potential to impair the cognitive function, but the effects of acute hypoxia on the cognitive function remain debatable. We investigated the effects of acute hypoxia on human cognitive processing using electroencephalographic event-related potentials and somatosensory-evoked potentials. Acute normobaric hypoxia impaired neural activity in motor executive and inhibitory processing, but no significant differences were observed in neural activity in somatosensory processing., 2017年11月01日, 123, 5, 1246, 1255, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Effects of face/head and whole body cooling during passive heat stress on human somatosensory processing, Hiroki Nakata; Mari Namba; Ryusuke Kakigi; Manabu Shibasaki, We herein investigated the effects of face/head and whole body cooling during passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs) at C4′ and Fz electrodes. Fourteen healthy subjects received a median nerve stimulation at the left wrist. SEPs were recorded at normothermic baseline (Rest), when esophageal temperature had increased by ~1.2°C (heat stress: HS) during passive heating, face/head cooling during passive heating (face/head cooling: FHC), and after HS (whole body cooling: WBC). The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4′ and P14, N18, P22, and N30 at Fz were evaluated. Latency indicated speed of the subcortical and cortical somatosensory processing, while amplitude reflected the strength of neural activity. Blood flow in the internal and common carotid arteries (ICA and CCA, respectively) and psychological comfort were recorded in each session. Increases in esophageal temperature due to HS significantly decreased the amplitude of N60, psychological comfort, and ICA blood flow in the HS session, and also shortened the latencies of SEPs (all, P < 0.05). While esophageal temperature remained elevated, FHC recovered the peak amplitude of N60, psychological comfort, and ICA blood flow toward preheat baseline levels as well as WBC. However, the latencies of SEPs did not recover in the FHC and WBC sessions. These results suggest that impaired neural activity in cortical somatosensory processing during passive HS was recovered by FHC, whereas conduction velocity in the ascending somatosensory input was accelerated by increases in body temperature., 2017年06月01日, 312, 6, R996, R1003, 研究論文(学術雑誌)
  • 査読あり, 英語, Scientific Reports, Suppression of cognitive function in hyperthermia; From the viewpoint of executive and inhibitive cognitive processing, Manabu Shibasaki; Mari Namba; Misaki Oshiro; Ryusuke Kakigi; Hiroki Nakata, 2017年04月, 7, 1, 研究論文(学術雑誌)
  • 査読あり, 日本語, 繊維製品消費科学, 暑熱環境下における認知機能, 芝﨑学; 中田大貴, 2017年01月, 58, 1, 50, 54, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Effects of aerobic exercise under different thermal conditions on human somatosensory processing, Hiroki Nakata; Misaki Oshiro; Mari Namba; Manabu Shibasaki, The present study aimed to investigate the effects of aerobic exercise on human somatosensory processing recorded by somatosensory evoked potentials (SEPs) under temperate [TEMP, 20°C and 40% relative humidity (RH)] and hot (HOT, 35°C and 30% RH) environments. Fifteen healthy subjects performed 4 × 15-min bouts of a moderate cycling exercise [mean power output: 156.5 ± 7.7 (SE) W], with a 10-min rest period and received a posterior tibial nerve stimulation at the left ankle before and after each exercise bout; SEPs were recorded in five sessions; 1st (pre), 2nd (post-1st exercise bout), 3rd (post-2nd exercise bout), 4th (post-3rd exercise bout), and 5th (post-4th exercise bout). The peak latencies and amplitudes of the P37, N50, P60, and N70 components at Cz were evaluated. The latencies of P37, N50, P60, and N70 were significantly shorter with the repetition of aerobic exercise, and these shortened latencies were significantly greater in the HOT condition than in the TEMP condition (P37: 3rd, P < 0.05, and 5th, P < 0.01; P60: 4th, P < 0.05, and 5th, P < 0.01; N70: 4th, P < 0.05, and 5th, P < 0.001). No significant differences were observed in the amplitudes of any SEP component under either thermal condition. These results suggest that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and aerobic exercise did not alter the strength of neural activity in cortical somatosensory processing., 2016年10月01日, 311, 4, R629, R636, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, The effect of elevations in internal temperature on event-related potentials during a simple cognitive task in humans, Manabu Shibasaki; Mari Namba; Misaki Oshiro; Craig G. Crandall; Hiroki Nakata, The effect of hyperthermia on cognitive function remains equivocal, perhaps because of methodological discrepancy. Using electroencephalographic event-related potentials (ERPs), we tested the hypothesis that a passive heat stress impairs cognitive processing. Thirteen volunteers performed repeated auditory oddball paradigms under two thermal conditions, normothermic time control and heat stress, on different days. For the heat stress trial, these paradigms were performed at preheat stress (i.e., normothermic) baseline, when esophageal temperature had increased by ∼0.8°C, when esophageal temperature had increased by ∼2.0°C, and during cooling following the heat stress. The reaction time and ERPs were recorded in each session. For the time control trial, subjects performed the auditory oddball paradigms at approximately the same time interval as they did in the heat stress trial. The peak latency and amplitude of an indicator of auditory processing (N100) were not altered regardless of thermal conditions. An indicator of stimulus classification/evaluation time (latency of P300) and the reaction time were shortened during heat stress; moreover an indicator of cognitive processing (the amplitude of P300) was significantly reduced during severe heat stress (8.3 ± 1.3 μV) relative to the baseline (12.2 ± 1.0 μV, P < 0.01). No changes in these indexes occurred during the time control trial. During subsequent whole body cooling, the amplitude of P300 remained reduced, and the reaction time and latency of P300 remained shortened. These results suggest that excessive elevations in internal temperature reduce cognitive processing but promote classification time., 2016年07月01日, 311, 1, R33, R38, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, Effects of passive heat stress on human somatosensory processing, Hiroki Nakata; Misaki Oshiro; Mari Namba; Manabu Shibasaki, Herein, we investigated the effects of passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs). Fifteen healthy subjects received a median nerve stimulation at the left wrist under two thermal conditions: Heat Stress and normothermic Time Control. The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4′ and P14, N18, P22, and N30 at Fz were evaluated. Under the Heat Stress condition, SEPs were recorded at normothermic baseline (1st), early in heat stress (2nd), when esophageal temperature had increased by ∼1.0°C (3rd) and ∼2.0°C (4th), and after heat stress (5th). In the Time Control condition, SEPs were measured at the same time intervals as those in the Heat Stress condition. The peak latencies and amplitudes of SEPs did not change early in heat stress. However, the latencies of P14, N20, and N60 at C4′ and P14, N18, and P22 at Fz were significantly shorter in the 4th session than in the 1st session. Furthermore, the peak amplitudes of P25 and N60 at C4′, and P22 and N30 at Fz decreased with increases in body temperature. On the other hand, under the Time Control condition, no significant differences were observed in the amplitudes or latencies of any component of SEPs. These results suggested that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and hyperthermia impaired the neural activity of cortical somatosensory processing., 2015年12月01日, 309, 11, R1387, R1396, 研究論文(学術雑誌)
  • 査読あり, 英語, American Journal of Physiology-Heart and Circulatory Physiology, The role of cardiac sympathetic innervation and skin thermoreceptors on cardiac responses during heat stress, Manabu Shibasaki; Yasunori Umemoto; Tokio Kinoshita; Ken Kouda; Tomoyuki Ito; Takeshi Nakamura; Craig G. Crandall; Fumihiro Tajima, The mechanism(s) for the changes in cardiac function during heat stress remain unknown. This study tested two unique hypotheses. First, sympathetic innervation to the heart is required for increases in cardiac systolic function during heat stress. This was accomplished by comparing responses during heat stress between paraplegics versus tetraplegics, with tetraplegics having reduced/absent cardiac sympathetic innervation. Second, stimulation of skin thermoreceptors contributes to cardiovascular adjustments that occur during heat stress in humans. This was accomplished by comparing responses during leg only heating between paraplegic versus able-bodied individuals. Nine healthy able-bodied, nine paraplegics, and eight tetraplegics participated in this study. Lower body (i.e., nonsensed area for para/tetraplegics) was heated until esophageal temperature had increased by ∼1.0°C. Echocardiographic indexes of diastolic and systolic function were performed before and at the end of heat stress. The heat stress increased cardiac output in all groups, but the magnitude of this increase was attenuated in the tetraplegics relative to the able-bodied (1.3 ± 0.4 vs. 2.3 ± 1.0 l/min; P < 0.05). Diastolic function was maintained in all groups. Indexes of left atrial and ventricular systolic function were enhanced in the able-bodied, but did not change in tetraplegics, while these changes in paraplegics were attenuated relative to the able-bodied. These data suggest that the cardiac sympathetic innervation is required to achieve normal increases in cardiac systolic function during heat stress but not required to maintain diastolic function during this exposure. Second, elevated systolic function during heat stress primarily occurs as a result of increases in internal temperature, although stimulation of skin thermoreceptors may contribute., 2015年06月01日, 308, 11, H1336, H1342, 研究論文(学術雑誌), 国際誌
  • 日本語, 体育の科学., 暑熱環境下における体温調節., 2014年07月, 64, 7, 475, 480
  • 査読あり, 英語, EXPERIMENTAL PHYSIOLOGY, Blood flow in internal carotid and vertebral arteries during graded lower body negative pressure in humans, Shigehiko Ogoh; Kohei Sato; Kazunobu Okazaki; Tadayoshi Miyamoto; Ai Hirasawa; Tomoko Sadamoto; Manabu Shibasaki, New Findings What is the central question of this study? Recently, the heterogeneity of the cerebral arterial circulation has been argued. Orthostatic tolerance may be associated with an orthostatic stress-induced change in blood flow in vertebral arteries rather than in internal carotid arteries, because vertebral arteries supply blood to the medulla oblongata, which is the location of important cardiac, vasomotor and respiratory control centres. What is the main finding and its importance? The effect of graded orthostatic stress on vertebral artery blood flow is different from that on internal carotid artery blood flow. This response allows for the possibility that orthostatic tolerance may be associated with haemodynamic changes in posterior rather than anterior cerebral blood flow. Recently, the heterogeneity of the cerebral arterial circulation has been argued, but the characteristics of vertebral artery (VA) and internal carotid artery (ICA) blood flow during graded orthostatic stress remain unknown. We hypothesized that the change in blood flow in VA is not similar to that in ICA blood flow during graded orthostatic stress. We measured blood flows in both ICA and VA during graded lower body negative pressure (LBNP; -20, -35and -50mmHg) by using two colour-coded ultrasound systems. The effect of graded orthostatic stress on the VA blood flow was different from that on the ICA blood flow (LBNPxartery, P=0.006). The change in ICA blood flow was associated with the level of LBNP (r = 0.287, P=0.029), and a reduction in ICA blood flow from pre-LBNP was observed during -50mmHg LBNP (from 411 +/- 35 to 311 +/- 40mlmin(-1), P=0.044) without symptoms of presyncope. In contrast, VA blood flow was unchanged during graded LBNP compared with the baseline (P=0.597) relative to the reduction in ICA blood flow and thus there was no relationship between VA blood flow and the level of LBNP (r=0.167, P=0.219). These findings suggest that the change in ICA blood flow is due to the level of LBNP during graded orthostatic stress, but the change in VA blood flow is different from that in ICA blood flow across the different levels of LBNP. These findings provide the possibility that posterior cerebral blood flow decreases only during severe orthostatic stress and is therefore more likely to be linked with orthostatic tolerance., 2015年03月, 100, 3, 259, 266, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Hyperthermia modulates regional differences in cerebral blood flow to changes in CO2, Shigehiko Ogoh; Kohei Sato; Kazunobu Okazaki; Tadayoshi Miyamoto; Ai Hirasawa; Manabu Shibasaki, The purpose of this study was to assess blood flow responses to changes in carbon dioxide (CO2) in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA) during normothermic and hyperthermic conditions. Eleven healthy subjects aged 22 +/- 2 (SD) yr were exposed to passive whole body heating followed by spontaneous hypocapnic and hypercapnic challenges in normothermic and hyperthermic conditions. Right ICA, ECA, and VA blood flows, as well as left middle cerebral artery (MCA) mean blood velocity (V-mean), were measured. Esophageal temperature was elevated by 1.53 +/- 0.09 degrees C before hypocapnic and hypercapnic challenges during heat stress. Whole body heating increased ECA blood flow and cardiac output by 130 +/- 78 and 47 +/- 26%, respectively (P < 0.001), while blood flow (or velocity) in the ICA, MCA, and VA was reduced by 17 +/- 14, 24 +/- 18, and 12 +/- 7%, respectively (P < 0.001). Regardless of the thermal conditions, ICA and VA blood flows and MCA V-mean were decreased by hypocapnic challenges and increased by hypercapnic challenges. Similar responses in ECA blood flow were observed in hyperthermia but not in normothermia. Heat stress did not alter CO2 reactivity in the MCA and VA. However, CO2 reactivity in the ICA was decreased (3.04 +/- 1.17 vs. 2.23 +/- 1.03%/mmHg; P +/- 0.039) but that in the ECA was enhanced (0.45 +/- 0.47 vs. 0.95 +/- 0.61%/mmHg; P = 0.032). These results indicate that hyperthermia is capable of altering dynamic cerebral blood flow regulation., 2014年07月, 117, 1, 46, 52, 研究論文(学術雑誌)
  • 査読あり, 英語, EXPERIMENTAL PHYSIOLOGY, Effects of acute hypoxia on cerebrovascular responses to carbon dioxide, Shigehiko Ogoh; Hidehiro Nakahara; Shinya Ueda; Kazunobu Okazaki; Manabu Shibasaki; Andrew W. Subudhi; Tadayoshi Miyamoto, New Findings What is the central question of this study? In acute hypoxia, the reduction in arterial CO2 tension due to the hypoxic ventilatory response (respiratory chemoreflex) stimulates cerebral vasoconstriction, which opposes the degree of hypoxic cerebral vasodilatation. The aim was to examine this interaction further. Specifically, we questioned whether arterial CO2 tension-mediated effects on cerebrovascular regulation are attenuated during acute hypoxia. What is the main finding and its importance? Cerebrovascular CO2 reactivity and CO2-mediated effects on dynamic cerebral autoregulation were attenuated during acute hypoxia. These findings suggest that blunted cerebrovascular responses to CO2 may limit the degree of CO2-mediated vasoconstriction to help maintain adequate cerebral blood flow for cerebral O2 homeostasis during acute hypoxia. In normoxic conditions, a reduction in arterial carbon dioxide tension causes cerebral vasoconstriction, thereby reducing cerebral blood flow and modifying dynamic cerebral autoregulation (dCA). It is unclear to what extent these effects are altered by acute hypoxia and the associated hypoxic ventilatory response (respiratory chemoreflex). This study tested the hypothesis that acute hypoxia attenuates arterial CO2 tension-mediated regulation of cerebral blood flow to help maintain cerebral O2 homeostasis. Eight subjects performed three randomly assigned respiratory interventions following a resting baseline period, as follows: (1) normoxia (21% O2); (2) hypoxia (12% O2); and (3) hypoxia with wilful restraint of the respiratory chemoreflex. During each intervention, 0, 2.0, 3.5 or 5.0% CO2 was sequentially added (8 min stages) to inspired gas mixtures to assess changes in steady-state cerebrovascular CO2 reactivity and dCA. During normoxia, the addition of CO2 increased internal carotid artery blood flow and middle cerebral artery mean blood velocity (MCAVmean), while reducing dCA (change in phase=-0.73 +/- 0.22rad, P=0.005). During acute hypoxia, internal carotid artery blood flow and MCAVmean remained unchanged, but cerebrovascular CO2 reactivity (internal carotid artery, P=0.003; MCAVmean, P=0.031) and CO2-mediated effects on dCA (P=0.008) were attenuated. The effects of hypoxia were not further altered when the respiratory chemoreflex was restrained. These findings support the hypothesis that arterial CO2 tension-mediated effects on the cerebral vasculature are reduced during acute hypoxia. These effects could limit the degree of hypocapnic vasoconstriction and may help to regulate cerebral blood flow and cerebral O2 homeostasis during acute periods of hypoxia., 2014年06月, 99, 6, 849, 858, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM, Blood flow distribution during heat stress: cerebral and systemic blood flow, Shigehiko Ogoh; Kohei Sato; Kazunobu Okazaki; Tadayoshi Miyamoto; Ai Hirasawa; Keiko Morimoto; Manabu Shibasaki, The purpose of the present study was to assess the effect of heat stress-induced changes in systemic circulation on intra- and extracranial blood flows and its distribution. Twelve healthy subjects with a mean age of 22 +/- 2 (s.d.) years dressed in a tube-lined suit and rested in a supine position. Cardiac output (Q), internal carotid artery (ICA), external carotid artery (ICA), and vertebral artery (VA) blood flows were measured by ultrasonography before and during whole body heating. Esophageal temperature increased from 37.0 +/- 0.2 degrees C to 38.4 +/- 0.2 degrees C during whole body heating. Despite an increase in Q (59 +/- 31%, P<0.001), ICA and VA decreased to 83 +/- 15% (P=0.001) and 87 +/- 8% (P=0.002), respectively, whereas ECA blood flow gradually increased from 188 +/- 72 to 422 +/- 189 mL/minute (135%, P<0.001). These findings indicate that heat stress modified the effect of Q on blood flows at each artery; the increased Q due to heat stress was redistributed to extracranial vascular beds., 2013年12月, 33, 12, 1915, 1920, 研究論文(学術雑誌)
  • 査読あり, 英語, The journal of physical fitness and sports medicine : JPFSM, The Japanese Society of Physical Fitness and Sports Medicine, Aging and thermoregulation, Shibasaki Manabu; Okazaki Kazunobu; Inoue Yoshimitsu, Global warming is now recognized worldwide. Thermoregulation is critical for human survival when exposed to a severely hot environment. Thermoregulation is closely related to physical fitness, but fitness decreases with advancing age. Thus, thermoregulatory functions also decline with age. In fact, several major heat waves have occurred around the world in the last 10 years, and the mortality ratio was further elevated in elderly people. We encourage exercise training in the elderly to maintain physical fitness, but we should also recognize how human thermoregulation alters with aging. The primary role of thermoregulatory functions is to maintain the internal body temperature within a narrow range. Internal body temperature is regulated by the thermal balance between heat production and heat dissipation. Older individuals have relatively low heat production, impaired thermal perception, and reduced autonomic and behavioral thermoregulatory responses. However, these diminished thermoregulatory functions can be improved, although the gain is lower or limited relative to their younger counterparts. We summarize thermoregulatory functioning in elderly people based on recent publications and our findings., 2013年04月, 2, 1, 37, 47, 研究論文(学術雑誌)
  • 査読あり, 日本語, 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, 那智勝浦町における被災地支援活動, 西弘子; 城本依穂; 喜田弘美; 坂口千恵子; 柳川敦子; 網野美佐; 中村健; 坂野元彦; 河﨑敬; 佐藤泰子; 田島文博; 芝﨑学,

    平成2393日,和歌山県那智勝浦町は台風12号により甚大な被害を受けた.台風災害直後より,町立病院と町保健師が協力し被災地支援活動を行った.病院スタッフと町保健師により,被災地に開設した救護所と避難所において医療支援活動を行った.この活動を通して,避難所における環境不備による健康問題が明らかになった.また,衣料支援における問題点も明らかとなり,下着,靴下,男性用のズボンの供給不足などが問題となった.

    , 2013年03月, 54, 3, 37-40, 246
  • 査読あり, 英語, CLINICAL AUTONOMIC RESEARCH, Muscle sympathetic responses during orthostasis in heat-stressed individuals, Jian Cui; Manabu Shibasaki; David A. Low; David M. Keller; Scott L. Davis; Craig G. Crandall, Whole-body heat stress compromises the control of blood pressure during an orthostatic challenge, although the extent to which this occurs can vary greatly between individuals. The mechanism(s) responsible for these varying responses remain unclear. This study tested the hypothesis that the individuals who are best able to tolerate an orthostatic challenge while heat stressed are the ones with the largest increase in sympathetic activity during orthostasis, indexed from recordings of muscle sympathetic nerve activity (MSNA). MSNA, arterial blood pressure, and heart rate were recorded from 11 healthy volunteers throughout passive whole-body heating and during 15 min of 60A degrees head-up tilt (HUT) or until the onset of pre-syncopal symptoms. Whole-body heating significantly increased core temperature (similar to 0.9A degrees C), supine heart rate and MSNA. Eight of 11 subjects developed pre-syncopal symptoms resulting in early termination of HUT. The HUT tolerance time was positively correlated (R = 0.82, P = 0.01) with the increase in MSNA by HUT. These data suggest that the individuals with the largest increase in MSNA during upright tilt have the greatest capacity to withstand the orthostatic challenge while heat stressed., 2011年12月, 21, 6, 381, 387, 研究論文(学術雑誌)
  • 査読あり, 英語, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, Modelflow underestimates cardiac output in heat-stressed individuals, Manabu Shibasaki; Thad E. Wilson; Morten Bundgaard-Nielsen; Thomas Seifert; Niels H. Secher; Craig G. Crandall, An estimation of cardiac output can be obtained from arterial pressure waveforms using the Modelflow method. However, whether the assumptions associated with Modelflow calculations are accurate during whole body heating is unknown. This project tested the hypothesis that cardiac output obtained via Modelflow accurately tracks thermodilution-derived cardiac outputs during whole body heat stress. Acute changes of cardiac output were accomplished via lower-body negative pressure (LBNP) during normothermic and heat-stressed conditions. In nine healthy normotensive subjects, arterial pressure was measured via brachial artery cannulation and the volume-clamp method of the Finometer. Cardiac output was estimated from both pressure waveforms using the Modeflow method. In normothermic conditions, cardiac outputs estimated via Modelflow (arterial cannulation: 6.1 +/- 1.0 l/min; Finometer 6.3 +/- 1.3 l/min) were similar with cardiac outputs measured by thermodilution (6.4 +/- 0.8 l/min). The subsequent reduction in cardiac output during LBNP was also similar among these methods. Whole body heat stress elevated internal temperature from 36.6 +/- 0.3 to 37.8 +/- 0.4 degrees C and increased cardiac output from 6.4 +/- 0.8 to 10.9 +/- 2.0 l/min when evaluated with thermodilution (P < 0.001). However, the increase in cardiac output estimated from the Modelflow method for both arterial cannulation (2.3 +/- 1.1 l/min) and Finometer (1.5 +/- 1.2 l/min) was attenuated compared with thermodilution (4.5 +/- 1.4 l/min, both P < 0.01). Finally, the reduction in cardiac output during LBNP while heat stressed was significantly attenuated for both Modelflow methods (cannulation: -1.8 +/- 1.2 l/min, Finometer: -1.5 +/- 0.9 l/min) compared with thermodilution (-3.8 +/- 1.19 l/min). These results demonstrate that the Modelflow method, regardless of Finometer or direct arterial waveforms, underestimates cardiac output during heat stress and during subsequent reductions in cardiac output via LBNP., 2011年02月, 300, 2, R486, R491, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans, Jonathan E. Wingo; David A. Low; David M. Keller; R. Matthew Brothers; Manabu Shibasaki; Craig G. Crandall, Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34 C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34 degrees C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20 degrees C (2 sites) or maintenance at 34 degrees C (2 sites). In both protocols, individuals were then passively heated to increase core temperature similar to 1 degrees C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 +/- 1.2 vs. 1.0 +/- 0.7 mg.cm(-2).min(-1).degrees C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 +/- 0.9 vs. 0.07 +/- 0.05 mg.cm(-2).min(-1).degrees C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 +/- 0.4 vs. 37.6 +/- 0.4 degrees C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature., 2010年11月, 109, 5, 1301, 1306, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Heat stress attenuates the increase in arterial blood pressure during the cold pressor test, Jian Cui; Manabu Shibasaki; David A. Low; David M. Keller; Scott L. Davis; Craig G. Crandall, The mechanisms by which heat stress impairs the control of blood pressure leading to compromised orthostatic tolerance are not thoroughly understood. A possible mechanism may be an attenuated blood pressure response to a given increase in sympathetic activity. This study tested the hypothesis that whole body heating attenuates the blood pressure response to a non-baroreflex-mediated sympathoexcitatory stimulus. Ten healthy subjects were instrumented for the measurement of integrated muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP), heart rate, sweat rate, and forearm skin blood flow. Subjects were exposed to a cold pressor test (CPT) by immersing a hand in an ice water slurry for 3 min while otherwise normothermic and while heat stressed (i.e., increase core temperature similar to 0.7 degrees C via water-perfused suit). Mean responses from the final minute of the CPT were evaluated. In both thermal conditions CPT induced significant increases in MSNA and MAP without altering heart rate. Although the increase in MSNA to the CPT was similar between thermal conditions (normothermia: Delta 14.0 +/- 2.6; heat stress: Delta 19.1 +/- 2.6 bursts/min; P = 0.09), the accompanying increase in MAP was attenuated when subjects were heat stressed (normothermia: Delta 25.6 +/- 2.3, heat stress: Delta 13.4 +/- 3.0 mmHg; P < 0.001). The results demonstrate that heat stress can attenuate the pressor response to a sympathoexcitatory stimulus., 2010年11月, 109, 5, 1354, 1359, 研究論文(学術雑誌)
  • 査読あり, 英語, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, Insufficient cutaneous vasoconstriction leading up to and during syncopal symptoms in the heat stressed human, C. G. Crandall; M. Shibasaki; T. E. Wilson, Crandall CG, Shibasaki M, Wilson TE. Insufficient cutaneous vasoconstriction leading up to and during syncopal symptoms in the heat stressed human. Am J Physiol Heart Circ Physiol 299: H1168-H1173, 2010. First published August 6, 2010; doi:10.1152/ajpheart.00290.2010.-As much as 50% of cardiac output can be distributed to the skin in the hyperthermic human, and therefore the control of cutaneous vascular conductance (CVC) becomes critical for the maintenance of blood pressure. Little is known regarding the magnitude of cutaneous vasoconstriction in profoundly hypotensive individuals while heat stressed. This project investigated the hypothesis that leading up to and during syncopal symptoms associated with combined heat and orthostatic stress, reductions in CVC are inadequate to prevent syncope. Using a retrospective study design, we evaluated data from subjects who experienced syncopal symptoms during lower body negative pressure (N = 41) and head-up tilt (N = 5). Subjects were instrumented for measures of internal temperature, forearm skin blood flow, arterial pressure, and heart rate. CVC was calculated as skin blood flow/mean arterial pressure x 100. Data were obtained while subjects were normothermic, immediately before an orthostatic challenge while heat stressed, and at 5-s averages for the 2 min preceding the cessation of the orthostatic challenge due to syncopal symptoms. Whole body heat stress increased internal temperature (1.25 +/- 0.3 degrees C; P < 0.001) and CVC (29 +/- 20 to 160 +/- 58 CVC units; P < 0.001) without altering mean arterial pressure (83 +/- 7 to 82 +/- 6 mmHg). Mean arterial pressure was reduced to 57 +/- 9 mmHg (P < 0.001) immediately before the termination of the orthostatic challenge. At test termination, CVC decreased to 138 +/- 61 CVC units (P < 0.001) relative to before the orthostatic challenge but remained approximately fourfold greater than when subjects were normothermic. This negligible reduction in CVC during pronounced hypotension likely contributes to reduced orthostatic tolerance in heat-stressed humans. Given that lower body negative pressure and head-up tilt are models of acute hemorrhage, these findings have important implications with respect to mechanisms of compromised blood pressure control in the hemorrhagic individual who is also hyperthermic (e.g., military personnel, firefighters, etc.)., 2010年10月, 299, 4, H1168, H1173, 研究論文(学術雑誌)
  • 査読あり, 英語, Frontiers in Bioscience - Scholar, Mechanisms and controllers of eccrine sweating in humans, Manabu Shibasaki; Craig G. Crandall, Human body temperature is regulated within a very narrow range. When exposed to hyperthermic conditions, via environmental factors and/or increased metabolism, heat dissipation becomes vital for survival. In humans, the primary mechanism of heat dissipation, particularly when ambient temperature is higher than skin temperature, is evaporative heat loss secondary to sweat secretion from eccrine glands. While the primary controller of sweating is the integration between internal and skin temperatures, a number of non-thermal factors modulate the sweating response. In addition to summarizing the current understanding of the neural pathways from the brain to the sweat gland, as well as responses at the sweat gland, this review will highlight findings pertaining to studies of proposed non-thermal modifiers of sweating, namely, exercise, baroreceptor loading state, and body fluid status. Information from these studies not only provides important insight pertaining to the basic mechanisms of sweating, but also perhaps could be useful towards a greater understanding of potential mechanisms and consequences of disease states as well as aging in altering sweating responses and thus temperature regulation., 2010年01月01日, 2, 2, 685, 696, 研究論文(学術雑誌)
  • 査読あり, 英語, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 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., 2009年12月, 297, 6, R1706, R1712, 研究論文(学術雑誌)
  • 査読あり, 英語, BRITISH JOURNAL OF DERMATOLOGY, Botulinum toxin abolishes sweating via impaired sweat gland responsiveness to exogenous acetylcholine, M. Shibasaki; S. L. Davis; J. Cui; D. A. Low; D. M. Keller; C. G. Crandall, Background Botulinum toxin A (BTX) disrupts neurotransmitter release from cholinergic nerves. The effective duration of impaired sweat secretion with BTX is longer relative to that of impaired muscle contraction, suggesting different mechanisms in these tissues. Objectives The aim of this study was to test the hypothesis that BTX is capable of altering sweating by reducing the responsiveness of the sweat gland to acetylcholine. Methods BTX was injected into the dorsal forearm skin of healthy subjects at least 3 days before subsequent assessment. On the day of the experiment, intradermal microdialysis probes were placed within the BTX-treated area and in an adjacent untreated area. Incremental doses of acetylcholine were administered through the microdialysis membranes while the sweat rate (protocol 1; n = 8) or a combination of sweat rate and skin blood flow (protocol 2; n = 8) were assessed. Results A relative absence of sweating was observed at the BTX site for both protocols (protocol 1: 0.05 +/- 0.09 mg cm(-2) min(-1); protocol 2: 0.03 +/- 0.04 mg cm(-2) min(-1), both at the highest dose of acetylcholine), while the sweat rate increased appropriately at the control sites (protocol 1: 0 90 +/- 0 46 mg cm(-2) min(-1); protocol 2: 1 07 +/- 0 67 mg cm(-2) min(-1)). Cutaneous vascular conductance increased to a similar level at both the BTX and control sites. Conclusions These results demonstrate that BTX is capable of inhibiting sweat secretion by reducing the responsiveness of the sweat gland to acetylcholine, while not altering acetylcholine-mediated cutaneous vasodilatation., 2009年10月, 161, 4, 757, 761, 研究論文(学術雑誌)
  • 査読あり, 英語, Clinical physiology and functional imaging, Early activation of the coagulation system during lower body negative pressure, 芝﨑学, 2009年10月, 29, 6, 427-430
  • 査読あり, 英語, Journal of Burn Care and Research, Sustained impairments in cutaneous vasodilation and sweating in grafted skin following long-term recovery, Scott L. Davis; Manabu Shibasaki; David A. Low; Jian Cui; David M. Keller; Jonathan E. Wingo; Gary F. Purdue; John L. Hunt; Brett D. Arnoldo; Karen J. Kowalske; Craig G. Crandall, We previously identified impaired cutaneous vasodilation and sweating in grafted skin 5 to 9 months postsurgery. The aim of this investigation was to test the hypothesis that cutaneous vasodilation, but not sweating, is restored as the graft heals. Skin blood flow and sweat rate were assessed from grafted skin and adjacent noninjured skin in three groups of subjects: 5 to 9 months postsurgery (n = 13), 2 to 3 years postsurgery (n = 13), and 4 to 8 years postsurgery (n = 13) during three separate protocols: 1) whole-body heating and cooling, 2) local administration of vasoactive drugs, and 3) local heating and cooling. Cutaneous vasodilation and sweating during whole-body heating were significantly lower (P < .001) in grafted skin when compared with noninjured skin across all groups and demonstrated no improvements with recovery time postsurgery. Maximal endothelial-dependent (acetylcholine) and endothelial-independent (sodium nitroprusside) cutaneous vasodilation remained attenuated (P < .001) in grafted skin up to 4 to 8 years postsurgery, indicating postsynaptic impairments. In grafted skin, cutaneous vasoconstriction during whole-body and local cooling was preserved, whereas vasodilation to local heating was impaired, regardless of the duration postsurgery. Split-thickness skin grafts have impaired cutaneous vasodilation and sweating up to 4 to 8 years postsurgery, thereby limiting the capability of this skin's contribution to thermoregulation during a heats stress. In contrast, grafted skin has preserved vasoconstrictor capacity. Copyright © 2009 by the American Burn Association., 2009年07月, 30, 4, 675, 685, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Neural and non-neural control of skin blood flow during isometric handgrip exercise in the heat stressed human, Manabu Shibasaki; Peter Rasmussen; Niels H. Secher; Craig G. Crandall, During heat stress, isometric handgrip (IHG) exercise causes cutaneous vasoconstriction, but it remains controversial whether neural mechanisms are responsible for this observation. The objective of this study was to test the hypothesis that cutaneous vasoconstriction during IHG exercise in heat stressed individuals occurs via a neural mechanism. An axillary nerve blockade was performed to block efferent nerve traffic to the left forearm in seven healthy subjects. Two intradermal microdialysis probes were placed within forearm skin of the blocked area. Forearm skin blood flow was measured by laser-Doppler flowmetry over the microdialysis probes as well as from skin of the contralateral (unblocked) forearm. Cutaneous vascular conductance (CVC) was calculated from the ratio of skin blood flow to mean arterial pressure. Effectiveness of nerve blockade was verified by the absence of tactile sensation, as well as an absence of sweating and cutaneous vasodilatation during a whole-body heat stress. Upon this confirmation, adenosine was perfused through one of the microdialysis probes to increase skin blood flow similar to that of the unblocked site. After internal temperature increased similar to 0.7 degrees C, subjects performed 2 min of IHG exercise at 35% of maximal voluntary contraction using the non-blocked arm. IHG exercise significantly decreased CVC at the unblocked site (82.3 +/- 5.7 to 70.9 +/- 5.4%max, P = 0.005, means +/- s.e.m.) and the adenosine treated site of the blocked arm (75.2 +/- 7.2 to 68.3 +/- 6.6%max, P = 0.005), whereas CVC was unchanged at the blocked site that did not receive adenosine (15.7 +/- 2.8 to 13.7 +/- 2.0%max, P = 0.10). Importantly, the reduction in CVC was greater at the unblocked site than at the adenosine treated site (11.4 +/- 2.6 vs. 6.9 +/- 1.6%max, respectively, P = 0.01). These findings suggest that neural and non-neural mechanisms contribute to the reduction in forearm CVC during IHG exercise in heat stressed humans., 2009年05月, 587, 9, 2101, 2107, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Whole body heat stress attenuates baroreflex control of muscle sympathetic nerve activity during postexercise muscle ischemia, Jian Cui; Manabu Shibasaki; Scott L. Davis; David A. Low; David M. Keller; Craig G. Crandall, Cui J, Shibasaki M, Davis SL, Low DA, Keller DM, Crandall CG. Whole body heat stress attenuates baroreflex control of muscle sympathetic nerve activity during postexercise muscle ischemia. J Appl Physiol 106: 1125-1131, 2009. First published February 12, 2009; doi: 10.1152/japplphysiol.00135.2008.-Both whole body heat stress and stimulation of muscle metabolic receptors activate muscle sympathetic nerve activity (MSNA) through nonbaroreflex pathways. In addition to stimulating muscle metaboreceptors, exercise has the potential to increase internal temperature. Although we and others report that passive whole body heating does not alter the gain of the arterial baroreflex, it is unknown whether increased body temperature, often accompanying exercise, affects baroreflex function when muscle metaboreceptors are stimulated. This project tested the hypothesis that whole body heating alters the gain of baroreflex control of muscle sympathetic nerve activity (MSNA) and heart rate during muscle metaboreceptor stimulation engaged via postexercise muscle ischemia (PEMI). MSNA, blood pressure (BP, Finometer), and heart rate were recorded from 11 healthy volunteers. The volunteers performed isometric handgrip exercise until fatigue, followed by 2.5 min of PEMI. During PEMI, BP was acutely reduced and then raised pharmacologically using the modified Oxford technique. This protocol was repeated two to three times when volunteers were normothermic, and again during heat stress (increase core temperature similar to 0.7 degrees C) conditions. The slope of the relationship between MSNA and BP during PEMI was less negative (i.e., decreased baroreflex gain) during whole body heating when compared with the normothermic condition (-4.34 +/- 0.40 to -3.57 +/- 0.31 units.beat(-1).mmHg(-1), respectively; P = 0.015). The gain of baroreflex control of heart rate during PEMI was also decreased during whole body heating (P < 0.001). These findings indicate that whole body heat stress reduces baroreflex control of MSNA and heart rate during muscle metaboreceptor stimulation., 2009年04月, 106, 4, 1125, 1131, 研究論文(学術雑誌)
  • 査読あり, 英語, Global Environmental Research, Thermoregulatory adaptation in humans and its modifying factors, 芝﨑学, 2009年, 13, 1, 35-41
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Effect of elevated local temperature on cutaneous vasoconstrictor responsiveness in humans, Jonathan E. Wingo; David A. Low; David M. Keller; R. Matthew Brothers; Manabu Shibasaki; Craig G. Crandall, Wingo JE, Low DA, Keller DM, Brothers RM, Shibasaki M, Crandall CG. Effect of elevated local temperature on cutaneous vasoconstrictor responsiveness in humans. J Appl Physiol 106: 571-575, 2009. First published December 4, 2008; doi: 10.1152/japplphysiol.91249.2008.-Cutaneous vascular conductance (CVC) increases in response to local skin heating. Although attenuation of vasoconstrictor responsiveness due to local heating has been demonstrated, the mechanism(s) responsible for this attenuation remains unclear. Nitric oxide has been shown to at least partially contribute to this response, but other mechanisms also may be involved. The purpose of this study was to test the hypothesis that local heating diminishes cutaneous vasoconstrictor responsiveness through a nitric oxide-independent mechanism by altering postsynaptic reactivity to norepinephrine. A follow-up protocol tested the hypothesis that local heating attenuates the presynaptic release of neurotransmitters that cause vasoconstriction, also via non-nitric oxide mechanisms. In protocol I, CVC was assessed in eight subjects during administration of increasing doses of norepinephrine (via intradermal microdialysis) at adjacent sites separately heated to 34 degrees C and 40 degrees C. In protocol II, which was identical to, but separate from, protocol I, CVC was assessed in seven subjects during administration of increasing doses of tyramine, which causes release of neurotransmitters from adrenergic nerves. At each site for both protocols, nitric oxide synthesis was inhibited (via microdialysis administration of N(G)-nitro-L-arginine methyl ester) and flow was matched (via microdialysis administration of adenosine); therefore, temperature was the only variable that differed between the sites. For both protocols, nonlinear regression analysis revealed no difference (P > 0.05) in the effective drug concentration causing 50% of the vasoconstrictor response. Minimum CVC [6.3 +/- 2.0 and 9.0 +/- 4.0% of peak CVC (mean +/- SD) for protocol 1 and 19.3 +/- 9.3 and 20.5 +/- 11.9% of peak CVC for protocol II at 34 degrees C and 40 degrees C sites, respectively] was not different between sites. Independent of nitric oxide, local skin heating to 40 degrees C does not attenuate adrenergically mediated cutaneous vasoconstriction through pre- or postsynaptic mechanisms., 2009年02月, 106, 2, 571, 575, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Nitric oxide inhibits cutaneous vasoconstriction to exogenous norepinephrine, Manabu Shibasaki; David A. Low; Scott L. Davis; Craig G. Crandall, Shibasaki M, Low DA, Davis SL, Crandall CG. Nitric oxide inhibits cutaneous vasoconstriction to exogenous norepinephrine. J Appl Physiol 105: 1504-1508, 2008. First published September 18, 2008; doi:10.1152/japplphysiol.91017.2008.-Previously, we found that nitric oxide (NO) inhibits cutaneous vasoconstrictor responsiveness evoked by whole body cooling, as well as an orthostatic stress in the heat-stressed human (Shibasaki M, Durand S, Davis SL, Cui J, Low DA, Keller DM, Crandall CG. J Physiol 585: 627-634, 2007). However, it remains unknown whether this response occurs via NO acting through presynaptic or postsynaptic mechanisms. The aim of this study was to test the hypothesis that NO is capable of impairing cutaneous vasoconstriction via postsynaptic mechanisms. Skin blood flow was monitored over two forearm sites where intradermal micro-dialysis membranes were previously placed. Skin blood flow was elevated four-to fivefold through perfusion of the NO donor sodium nitroprusside at one site and through perfusion of adenosine (primarily non-NO mechanisms) at a second site. Once a plateau in vasodilation was evident, increasing concentrations of norepinephrine (1 x 10(-8) to 1 x 10(-2) M) were administrated through both microdialysis probes, while the aforementioned vasodilator agents continued to be perfused. Cutaneous vascular conductance was calculated by dividing skin blood flow by mean arterial blood pressure. The administration of norepinephrine decreased cutaneous vascular conductance at both sites. However, the dose of norepinephrine at the onset of vasoconstriction (-5.9 +/- 1.3 vs.-7.2 +/- 0.7 log M norepinephrine, P = 0.021) and the concentration of norepinephrine resulting in 50% of the maximal vasoconstrictor response (-4.9 +/- 1.2 vs. -6.1 +/- 0.2 log M norepinephrine dose; P = 0.012) occurred at significantly higher norepinephrine concentrations for the sodium nitroprusside site relative to the adenosine site, respectively. These results suggested that NO is capable of attenuating cutaneous vasoconstrictor responsiveness to norepinephrine via postsynaptic mechanisms., 2008年11月, 105, 5, 1504, 1508, 研究論文(学術雑誌)
  • 査読あり, 英語, MENOPAUSE-THE JOURNAL OF THE NORTH AMERICAN MENOPAUSE SOCIETY, Cutaneous and hemodynamic responses during hot flashes in symptomatic postmenopausal women, David A. Low; Scott L. Davis; David M. Keller; Manabu Shibasaki; Craig G. Crandall, Objective: The aim of this study was to test the hypothesis that the postmenopausal hot flash is accompanied by rapid decreases in arterial blood pressure and increases in cutaneous vascular conductance (CVC), as evaluated by continuous measurements of these variables in symptomatic women. Design: Twelve healthy, normotensive, postmenopausal women rested in a temperature-controlled laboratory (26 degrees C) for approximately 90 minutes. The onset of a hot flash was objectively identified as a transient and pronounced elevation of sternal sweat rate (capacitance hygrometry). Results: Twenty-three hot flashes were recorded during the experimental sessions (3.4 +/- 1.4 min; range, 1.3-6.5 min). Mean arterial blood pressure decreased 13 2 min Hg during 11 hot flashes in five participants. Data from these participants, categorized as responders, were analyzed separately from data for those participants whose blood pressure did not change during their hot flashes (n = 7, 12 hot flashes). Heart rate (obtained from an electrocardiogram) significantly increased during the hot flashes, but there was no difference between the responder and nonresponder groups (9 +/- 2 vs 10 +/- 1 beats/min, respectively; P > 0.05). The increase in CVC was not different between groups at either the forearm (15% +/- 3% vs 12% +/- 3% maximal CVC, P > 0.05) or sternum (24% +/- 5% vs 21% +/- 3% maximal CVC, P > 0.05). Conclusions: These data demonstrate that in a subset of participants, the hot flash is accompanied by a significant reduction in blood pressure, but there is no difference in CVC between these women and women with no drop in blood pressure., 2008年03月, 15, 2, 290, 295, 研究論文(学術雑誌)
  • 査読あり, 英語, Journal of Burn Care & Research, Cutaneous vasoconstriction during whole-body and local cooling in grafted skin 5-9 months post-surgery, 芝﨑学, 2008年01月, 29, 1, 36-41
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Endogenous nitric oxide attenuates neutrally mediated cutaneous vasoconstriction, Manabu Shibasaki; Sylvain Durand; Scott L. Davis; Jian Cui; David A. Low; David M. Keller; Craig G. Crandall, Cutaneous vasoconstrictor responsiveness may be impaired by substance(s) directly or indirectly responsible for cutaneous active vasodilatation. In this study, we tested the hypothesis that endogenous nitric oxide (NO) attenuates the reduction in cutaneous vascular conductance (CVC) during an orthostatic challenge combined with whole-body heating, as well as during whole-body cooling. In protocol 1, healthy subjects were pretreated with an intradermal injection of botulinum toxin A (BTX) to block the release of neurotransmitters from nerves responsible for cutaneous active vasodilatation. On the experimental day, a microdialysis probe was placed at the BTX-treated site as well as at two adjacent untreated sites. N-G-nitro-L-arginine methyl ester (L-NAME, 10 mM) was perfused through the probe placed at the BTX-treated site and at one untreated site. After confirmation of the absence of cutaneous vasodilatation at the BTX site during whole-body heating, adenosine was infused through the microdialysis probe at this site to increase skin blood flow to a level similar to that at the untreated site. Subsequently, 30 and 40 mmHg lower-body negative pressures (LBNPs) were applied. The reduction in CVC to LBNP was greatest at the BTX-treated site (15.0 +/- 2.4% of the maximum level (% max)), followed by the L-NAME-treated site (11.3 +/- 2.6% max), and then the untreated site (3.8 +/- 3.0% max; P < 0.05 for all comparisons). In protocol 2, two microdialysis membranes were inserted in the dermal space of one forearm. Adenosine alone was infused at one site while the other site received adenosine and L-NAME. The reduction in CVC in response to whole-body cooling was significantly greater at the L-NAME-treated site than at the adjacent adenosine alone site. These results suggest that endogenous NO is capable of attenuating cutaneous vasoconstrictor responsiveness., 2007年12月, 585, 2, 627, 634, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Does local heating-induced nitric oxide production attenuate vasoconstrictor responsiveness to lower body negative pressure in human skin?, David A. Low; Manabu Shibasaki; Scott L. Davis; David M. Keller; Craig G. Crandall, We tested the hypothesis that local heating-induced nitric oxide (NO) production attenuates cutaneous vasoconstrictor responsiveness. Eleven subjects (6 men, 5 women) had four microdialysis membranes placed in forearm skin. Two membranes were perfused with 10 mM of N-G-nitro-L-arginine (L-NAME) and two with Ringer solution (control), and all sites were locally heated to WC. Subjects then underwent 5 min of 60-mmHg lower body negative pressure (LBNP). Two sites (a control and an L-NAME site) were then heated to 39 degrees C, while the other two sites were heated to 42 degrees C. At the L-NAME sites, skin blood flow was elevated using 0.75-2 mg/ml of adenosine in the perfusate solution (Adn + L-NAME) to a similar level relative to control sites. Subjects then underwent another 5 min of 60-mmHg LBNP. At 34 degrees C, cutaneous vascular conductance (CVC) decreased (A) similarly at both control and L-NAME sites during LBNP (Delta 7.9 +/- 3.0 and Delta 3.4 +/- 0.8% maximum, respectively; P > 0.05). The reduction in CVC to LBNP was also similar between control and Adn + L-NAME sites at 39 degrees C (control Delta 11.4 +/- 2.5 vs. Adn + L-NAME Delta 7.9 +/- 2.0% maximum; P > 0.05) and 42 degrees C (control Delta 1.9 +/- 2.7 vs. Adn + L-NAME Delta 4.2 +/- 2.7% maximum; P > 0.05). However, the decrease in CVC at 42 degrees C, regardless of site, was smaller than at 39 degrees C (P < 0.05). These results do not support the hypothesis that local heating-induced NO production attenuates cutaneous vasoconstrictor responsiveness during high levels of LBNP. However, elevated local temperature, per se, attenuates cutaneous vasoconstrictor responsiveness to LBNP, presumably through non-nitric oxide mechanisms., 2007年05月, 102, 5, 1839, 1843, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF BURN CARE & RESEARCH, Impaired cutaneous vasodilation and sweating in grafted skin during whole-body heating, Scott L. Davis; Manabu Shibasaki; David A. Low; Jian Cui; David M. Keller; Gary F. Purdue; John L. Hunt; Brett D. Arnoldo; Karen J. Kowalske; Craig G. Crandall, The aim of this investigation was to identify the consequences of skin grafting on cutaneous vasodilation and sweating in split-thickness grafted skin during indirect whole-body heating 5 to 9 months after surgery. In addition, thermoregulatory function was examined at donor skin sites on a separate day. Skin blood flow and sweat rate (SR) were assessed from both grafted (n = 14) or donor skin (n = 11) and compared with the respective adjacent control skin during indirect whole-body heating. Cutaneous vascular conductance (CVC) was calculated from the ratio of skin blood flow (arbitrary units; au) to mean arterial pressure. Whole-body heating significantly increased internal temperature (37.0 +/- 0.1 degrees C to 37.8 +/- 0.1 degrees C; P <.05). Cutaneous vasodilation (ie, the increase in CVC from baseline, Delta CVC) during whole-body heating was significantly attenuated in grafted skin (Delta CVC = 0.14 +/- 0.15 au/mm Hg) compared with adjacent control skin (Delta CVC = 0.84 +/- 0.11 au/mm Hg; P <.05). Increases in sweat rate (ASR) were also significantly lower in grafted skin (ASR = 0.08 +/- 0.08 mg/cm(2)/min) compared with adjacent control skin (ASR = 1.16 +/- 0.20 mg/ cm(2)/min; P <.05). Cutaneous vasodilation and sweating during heating were not significantly different between donor sites (Delta CVC = 0.71 +/- 0.19 au/mm Hg; ASR = 1.04 0.15 mg/cm2/min) and adjacent control skin (Delta CVC = 0.50 +/- 0.10 au/mm Hg; ASR = 0.83 +/- 0.17 mg/cm(2)/min). Greatly attenuated or absence of cutaneous vasodilation and sweating suggests impairment of thermoregulatory function in grafted skin, thereby, diminishing the contribution of this skin to overall temperature control during a heat stress., 2007年05月, 28, 3, 427, 434, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF BURN CARE & RESEARCH, Skin grafting impairs postsynaptic cutaneous vasodilator and sweating responses, Scott L. Davis; Manabu Shibasaki; David A. Low; Jian Cui; David M. Keller; Gary F. Purdue; John L. Hunt; Brett D. Arnoldo; Karen J. Kowalske; Craig G. Crandall, This study tested the hypothesis that postsynaptic cutaneous vascular responses to endothelial-dependent and -independent vasodilators, as well as sweat gland function, are impaired in split-thickness grafted skin 5 to 9 months after surgery. Intradermal microdialysis membranes were placed in grafted and adjacent control skin, thereby allowing local delivery of the endothelial-dependent vasodilator, acetylcholine (ACh; 1 x 10(-7) to 1 x 10(-1) M at 10-fold increments) and the endothelial-independent nitric oxide donor, sodium nitroprusside (SNP; 5 x 10(-8) to 5 x 10(-2) M at 10-fold increments). Skin blood flow and sweat rate were simultaneously assessed over the semipermeable portion of the membrane. Cutaneous vascular conductance (CVC) was calculated from the ratio of laser Doppler-derived skin blood flow to mean arterial blood pressure. Delta CVC responses from baseline to these drugs were modeled via nonlinear regression curve fitting to identify the dose of ACh and SNP causing 50% of the maximal vasodilator response (EC50). A rightward shift in the CVC dose response curve for ACh was observed in grafted (EC50 = -2.61 +/- 0.44 log M) compared to adjacent control skin (EC50 = -3.34 +/- 0.46 log M; P =.003), whereas the mean EC50 for SNP was similar between grafted (EC50 = -4.21 +/- 0.94 log M) and adjacent control skin (EC50 = -3.87 +/- 0.65 log M; P = 0.332). Only minimal sweating to exogenous ACh was observed in grafted skin whereas normal sweating was observed in control skin. Increased EC50 and decreased maximal CVC responses to the exogenous administration of ACh suggest impairment of endothelial-dependent cutaneous vasodilator responses in grafted skin 5 to 9 months after surgery. Greatly attenuated sweating responses to ACh suggests either abnormal or an absence of functional sweat glands in the grafted skin., 2007年05月, 28, 3, 435, 441, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Carotid baroreceptor stimulation alters cutaneous vascular conductance during whole-body heating in humans, David M. Keller; Scott L. Davis; David A. Low; Manabu Shibasaki; Peter B. Raven; Craig G. Crandall, Prior studies investigating carotid baroreflex control of the cutaneous vasculature have yielded mixed findings. However, previously used methodological and analytical techniques may limit the ability to detect carotid baroreflex-mediated changes in cutaneous vascular conductance (CVC). The aim of this study was to test the hypothesis that dynamic carotid baroreceptor stimulation (i.e. 5 s trials) using neck pressure (NP, simulated carotid hypotension) and neck suction (NS, simulated carotid hypertension) will decrease and increase CVC, respectively, during normothermic and whole-body heating conditions in resting humans. Data were obtained from nine subjects (age, 31 +/- 2 year). The ratio of forearm skin blood flux (laser-Doppler flowmetry) and arterial blood pressure (Finapres) was used as an index of CVC. Multiple 5 s trials of NP (+40(Torr)) and NS (-60(Torr)), as well as breath-hold/airflow control trials, were applied during end-expiratory breath-holds while subjects were normotheric and heat stressed (change in core temperature similar to 0.75 degrees C). CVC responses to each NP and NS trial were averaged into 1 s intervals during the following periods: 3 s prestimulus, 5 s during stimulus, and 5 s poststimulus. Peak CVC responses (3 s average) to NP and NS were compared to prestimulus values using paired t test. During normothermia, NP decreased CVC by 0.032 +/- 0.007 arbitrary units (a.u.) mmHg(-1); (P < 0.05); however, breath-hold/airflow control trials resulted in similar decreases in CVC. NS did not change CVC (Delta= 0.002 +/- 0.005 a.u. mmHg(-1); P = 0.63). During whole-body heating, NP decreased CVC (by 0.16 +/- 0.04 a.u. mmHg(-1); (P < 0.05), whereas NS increased CVC by 0.07 +/- 0.03 a.u. mmHg(-1); (P < 0.05). Furthermore, these changes were greater than, or directionally different from, the breath-hold/airflow control trials. These findings indicate that carotid baroreceptor stimulation elicits dynamic changes in CVC and that these changes are more apparent during whole-body heating., 2006年12月, 577, 3, 925, 933, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Neurally mediated vasoconstriction is capable of decreasing skin blood flow during orthostasis in the heat-stressed human, Manabu Shibasaki; Scott L. Davis; Jian Cui; David A. Low; David M. Keller; Sylvain Durand; Craig G. Crandall, Given the large increase in cutaneous vascular conductance (CVC) during whole-body heat stress, this vascular bed is important in the regulation of blood pressure during orthostatic stress. In this thermal state, changes in CVC are reported to be due to withdrawal of active vasodilator activity. The purpose of this study was to identify, contrary to the current line of thinking, whether cutaneous vasoconstrictor neural activity is enhanced and capable of contributing to reductions in CVC during an orthostatic challenge of heat-stressed individuals. Healthy normotensive subjects were pretreated, subcutaneously, with botulinum toxin A (BTX-A) to inhibit the release of neurotransmitters from cutaneous active vasodilator nerves. On the experimental day, microdialysis probes were placed in the BTX-A-treated site and in an adjacent untreated site. In protocol 1, internal temperature was elevated similar to 0.7 degrees C, followed by the application of lower body negative pressure (LBNP; -30 mmHg). LBNP reduced CVC at the BTX-A-treated sites (Delta 4.2 +/- 2.9%max), as well as at the control site (Delta 9.8 +/- 4.1%max). In protocol 2, after confirming the absence of cutaneous vasodilatation at the BTX-A-treated site during whole-body heating, CVC at this site was elevated to a similar level relative to the control site (55.4 +/- 13.4 versus 60.7 +/- 10.4%max, respectively) via intradermal administration of isoproterenol prior to LBNP. Similarly, when flow was matched between sites, LBNP reduced CVC at both the BTX-A-treated (Delta 15.3 +/- 4.6%max) and the control sites (Delta 8.8 +/- 5.6%max). These data suggest that the cutaneous vasoconstrictor system is engaged and is capable of decreasing CVC during an orthostatic challenge in heat-stressed individuals., 2006年09月, 575, 3, 953, 959, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Neural control and mechanisms of eccrine sweating during heat stress and exercise, M Shibasaki; TE Wilson; CG Crandall, In humans, evaporative heat loss from eccrine sweat glands is critical for thermoregulation during exercise and/or exposure to hot environmental conditions, particularly when environmental temperature is greater than skin temperature. Since the time of the ancient Greeks, the significance of sweating has been recognized, whereas our understanding of the mechanisms and controllers of sweating has largely developed during the past century. This review initially focuses on the basic mechanisms of eccrine sweat secretion during heat stress and/or exercise along with a review of the primary controllers of thermoregulatory sweating (i.e., internal and skin temperatures). This is followed by a review of key nonthermal factors associated with prolonged heat stress and exercise that have been proposed to modulate the sweating response. Finally, mechanisms pertaining to the effects of heat acclimation and microgravity exposure are presented., 2006年05月, 100, 5, 1692, 1701
  • 査読あり, 英語, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, Spectral characteristics of skin sympathetic nerve activity in heat-stressed humans, J Cui; M Sathishkumar; TE Wilson; M Shibasaki; SL Davis; CG Crandall, Skin sympathetic nerve activity (SSNA) exhibits low- and high-frequency spectral components in normothermic subjects. However, spectral characteristics of SSNA in heat-stressed subjects are unknown. Because the main components of the integrated SSNA during heat stress (sudomotor/vasodilator activities) are different from those during normothermia and cooling (vasoconstrictor activity), we hypothesize that spectral characteristics of SSNA in heat-stressed subjects will be different from those in subjects subjected to normothermia or cooling. In 17 healthy subjects, SSNA, electrocardiogram, arterial blood pressure (via Finapres), respiratory activity, and skin blood flow were recorded during normothermia and heat stress. In 7 of the 17 subjects, these variables were also recorded during cooling. Spectral characteristics of integrated SSNA, R-R interval, beat-by-beat mean blood pressure, skin blood flow variability, and respiratory excursions were assessed. Heat stress and cooling significantly increased total SSNA. SSNA spectral power in the low- frequency (0.03-0.15 Hz), high-frequency (0.15-0.45 Hz), and very-high-frequency (0.45-2.5 Hz) regions was significantly elevated by heat stress and cooling. Interestingly, heat stress caused a greater relative increase of SSNA spectral power within the 0.45- to 2.5-Hz region than in the other spectral ranges; cooling did not show this effect. Differences in the SSNA spectral distribution between normothermia/cooling and heat stress may reflect different characteristics of central modulation of vasoconstrictor and sudomotor/vasodilator activities., 2006年04月, 290, 4, H1601, H1609, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Central command and the cutaneous vascular response to isometric exercise in heated humans, M Shibasaki; NH Secher; JM Johnson; CG Crandall, Cutaneous vascular conductance (CVC) decreases during isometric handgrip, exercise in heat stressed individuals, and we hypothesized that central command is involved in this response. Seven subjects performed 2 min of isometric handgrip exercise (35% of maximal voluntary contraction) followed by postexercise ischaemia in normothermia and during heat stress (increase in internal temperature similar to 1 degrees C). To augment the contribution of central command independent of force generation, on a separate day the protocol was repeated following partial neuromuscular blockade (PNB; i.v. cisatracurium). Forearm skin blood flow was measured by laser-Doppler flowmetry, and CVC was the ratio of skin blood flow to mean arterial pressure. The PNB attenuated force production despite encouragement to attain the same workload. During the heat stress trials, isometric exercise decreased CVC by similar to 12% for both conditions, but did not change CVC in either of the normothermic trials. During isometric exercise in the heat, the increase in mean arterial pressure (MAP) was greater during the control trial relative to the PNB trial (31.0 +/- 9.8 versus 18.6 +/- 6.4 mmHg, P < 0.01), while the elevation of heart rate tended to be lower (19.4 +/- 10.4 versus 27.4 +/- 8.1 b.p.m., P = 0.15). During postexercise ischaemia, CVC and MAP returned to pre-exercise levels in the PNB trial but remained reduced in the control trial. These findings suggest that central command, as well as muscle metabo-sensitive afferent stimulation, contributes to forearm cutaneous vascular responses in heat stressed humans., 2005年06月, 565, 2, 667, 673, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Muscle mechanoreceptor modulation of sweat rate during recovery from moderate exercise, M Shibasaki; M Sakai; M Oda; CG Crandall, The objective of this study was to identify whether muscle mechanoreceptor stimulation is capable of modulating sweat rate. Seven healthy subjects performed two 20-min bouts of supine exercise on a tandem cycle ergometer (60 rpm at 65% of maximal heart rate). After one bout, the subject stopped exercising (i.e., no pedaling), whereas, after the other bout, the subject's legs were passively cycled (at 60 rpm) via a second person cycling the tandem ergometer. This allows for mechanical stimulation of muscle with minimal activation of central command. Esophageal temperature (T-es), mean skin temperature ((T) over bar (sk)), heart rate, mean arterial blood pressure, oxygen consumption, cutaneous vascular conductance (CVC), and sweat rate were not different during the two exercise bouts. Regardless of the mode of exercise recovery, there were no differences in T-es, (T) over bar (sk), or CVC. In contrast, early in the recovery period, chest and forearm sweat rate were significantly greater in the passive cycling recovery mode relative to the no-pedaling condition (chest: 0.57 +/- 0.13 vs. 0.39 +/- 0.14, forearm: 0.30 +/- 0.05 vs. 0.12 +/- 0.02 mg.cm(-2).min(-1); both P < 0.05). These results suggested that muscle mechanoreceptor stimulation to the previously activated muscle is capable of modulating sweat rate., 2004年06月, 96, 6, 2115, 2119, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Central command is capable of modulating sweating from non-glabrous human skin, M Shibasaki; NH Secher; C Selmer; N Kondo; CG Crandall, Isometric handgrip, exercise (IHG) increases sweating rate without changing core or skin temperatures. The contribution of central command resulting in increases in sweating rate during IHG is unknown. To investigate this question, seven subjects performed IHG (35% maximum voluntary contraction (MVC) for 2 min) followed by 2-min of post-exercise ischaemia (PEI), with and without partial neuromuscular blockade (PNB). PNB was performed to augment central command during the IHG bout. These trials were conducted while the subject was normothermic, mildly heated, and moderately heated. On the non-exercising arm, forearm sweating rate was monitored over a microdialysis membrane perfused with neostigmine (acetylcholinesterase inhibitor), and at an adjacent untreated site. In normothermia with PNB, despite reduced force production during IHG (17 +/- 9 versus 157 +/- 13 N; P < 0.001), the elevation in sweating rate at the neostigmine-treated site was greater relative to the control IHG bout (P < 0.05). During subsequent PEI, for the PNB trial mean arterial blood pressure (MAP) and sweating rate returned towards pre-IHG levels, while during the control trial these variables remained elevated. During IHG while mildly heated, the elevation in sweating rate was greater during the PNB trial relative to the control trial. In contrast, during moderate heating sweating increased during IHG for both trials, however the elevation in sweating rate during the PNB trial was not greater than during the control trial. These results suggest that central command is capable of modulating sweating rate in all thermal conditions, however its effect is reduced when body temperatures and/or sweating rate are substantially elevated., 2003年12月, 553, 3, 999, 1004, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Exercise throughout 6°head-down tilt bed rest preserves thermoregulatory responses, 芝﨑学, Spaceflight and its bed rest analog [6degrees head-down tilt (HDT)]decrease plasma and blood volume and aerobic capacity. These responses may be associated with impaired thermoregulatory responses observed during exercise and passive heating after HDT exposure. This project tested the hypothesis that dynamic exercise during 13 days of HDT bed rest preserves thermoregulatory responses. Throughout HDT bed rest, 10 subjects exercised for 90 min/day (75% of pre-HDT maximum heart rate; supine). Before and after HDT bed rest, each subject exercised in the supine position at the same workload in a 28degreesC room. The internal temperature (T-core) threshold for the onset of sweating and cutaneous vasodilation, as well as the slope of the relationship between the elevation in T-core relative to the elevation in sweat rate (SR) and cutaneous vascular conductance (CVC; normalized to local heating maximum), were quantified pre- and post-HDT. T-core thresholds for the onset of cutaneous vasodilation on the chest and forearm (chest: 36.79 +/- 0.12 to 36.94 +/- 0.13degreesC, P = 0.28; forearm: 36.76 +/- 0.12 to 36.91 +/- 0.11degreesC, P = 0.16) and slope of the elevation in CVC relative to T-core (chest: 77.9 +/- 14.2 to 80.6 +/- 17.2% max/degreesC; P = 0.75; forearm: 76.3 +/- 11.8 to 67.5 +/- 14.3% max/degreesC, P = 0.39) were preserved post-HDT. Moreover, the T-core threshold for the onset of SR (36.66 +/- 0.12 to 36.74 +/- 0.10degreesC; P = 0.36) and the slope of the relationship between the elevation in SR and the elevation in T-core (1.23 +/- 0.19 to 1.01 +/- 0.14 mg.cm(-2).min(-1).degreesC(-1); P = 0.16) were also maintained. Finally, after HDT bed rest, peak oxygen uptake and plasma and blood volumes were not different relative to pre- HDT bed rest values. These data suggest that dynamic exercise during this short period of HDT bed rest preserves thermoregulatory responses., 2003年11月, 95, 5, 1817, 1823, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans, CG Crandall; M Shibasaki; TE Wilson; J Cui; BD Levine, Cutaneous vasodilation and sweat rate are reduced during a thermal challenge after simulated and actual microgravity exposure. The effects of microgravity exposure on cutaneous vasodilator capacity and on sweat gland function are unknown. The purpose of this study was to test the hypothesis that simulated microgravity exposure, using the 6degrees head-down tilt (HDT) bed rest model, reduces maximal forearm cutaneous vascular conductance (FVC) and sweat gland function and that exercise during HDT preserves these responses. To test these hypotheses, 20 subjects were exposed to 14 days of strict HDT bed rest. Twelve of those subjects exercised ( supine cycle ergometry) at 75% of pre-bed rest heart rate maximum for 90 min/day throughout HDT bed rest. Before and after HDT bed rest, maximal FVC was measured, via plethysmography, by heating the entire forearm to 42 degreesC for 45 min. Sweat gland function was assessed by administering 1 x 10(-6) to 2 M acetylcholine ( 9 doses) via intradermal microdialysis while simultaneously monitoring sweat rate over the microdialysis membranes. In the nonexercise group, maximal FVC and maximal stimulated sweat rate were significantly reduced after HDT bed rest. In contrast, these responses were unchanged in the exercise group. These data suggest that 14 days of simulated microgravity exposure, using the HDT bed rest model, reduces cutaneous vasodilator and sweating capacity, whereas aerobic exercise training during HDT bed rest preserves these responses., 2003年06月, 94, 6, 2330, 2336, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Effects of 14 days of head-down tilt bed rest on cutaneous vasoconstrictor responses in humans, TE Wilson; M Shibasaki; J Cui; BD Levine; CG Crandall, This study tested the hypothesis that head-down tilt bed rest (HDBR) reduces adrenergic and nonadrenergic cutaneous vasoconstrictor responsiveness. Additionally, an exercise countermeasure group was included to identify whether exercise during bed rest might counteract any vasoconstrictor deficits that arose during HDBR. Twenty-two subjects underwent 14 days of strict 6degrees HDBR. Eight of these 22 subjects did not exercise during HDBR, while 14 of these subjects exercised on a supine cycle ergometer for 90 min a day at 75% of pre-bed rest heart rate maximum. To assess alpha-adrenergic vasoconstrictor responsiveness, intradermal microdialysis was used to locally administer norepinephrine ( NE), while forearm skin blood flow (SkBF; laser-Doppler flowmetry) was monitored over microdialysis membranes. Nonlinear regression modeling was used to identify the effective drug concentration that caused 50% of the cutaneous vasoconstrictor response (EC50) and minimum values from the SkBF-NE dose-response curves. In addition, the effects of HDBR on nonadrenergic cutaneous vasoconstriction were assessed via the venoarteriolar response of the forearm and leg. HDBR did not alter EC50 or the magnitude of cutaneous vasoconstriction to exogenous NE administration regardless of whether the subjects exercised during HDBR. Moreover, HDBR did not alter the forearm venoarteriolar response in either the control or exercise groups during HDBR. However, HDBR significantly reduced the magnitude of cutaneous vasoconstriction due to the venoarteriolar response in the leg, and this response was similarly reduced in the exercise group. These data suggest that HDBR does not alter cutaneous vasoconstrictor responses to exogenous NE administration, whereas cutaneous vasoconstriction of the leg due to the venoarteriolar response is reduced after HDBR. It remains unclear whether attenuated venoarteriolar responses in the lower limbs contribute to reduced orthostatic tolerance after bed rest and spaceflight., 2003年06月, 94, 6, 2113, 2118, 研究論文(学術雑誌)
  • 査読あり, 英語, EXERCISE AND SPORT SCIENCES REVIEWS, Non-thermoregulatory modulation of sweating in humans, M Shibasaki; N Kondo; CG Crandall, SHIBASAKI, M., N. KONDO, and C.G. CRANDALL. Non-thermoregulatory modulation of sweating in humans. Exerc. Sport Sci. Rev., Vol. 31, No. 1, pp. 34-39, 2003. Sweating in humans is critical for appropriate thermoregulation during exercise and/or exposure to warm environmental temperatures. In addition to thermal controllers of sweating, a number of non-thermal factors modulate the sweating response. This review summarizes the primary non-thermal neural modifiers of sweating in humans., 2003年01月, 31, 1, 34, 39
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Acetylcholine released from cholinergic nerves contributes to cutaneous vasodilation during heat stress, M Shibasaki; TE Wilson; J Cui; CG Crandall, Nitric oxide (NO) contributes to active cutaneous vasodilation during a heat stress in humans. Given that acetylcholine is released from cholinergic nerves during whole body heating, coupled with evidence that acetylcholine causes vasodilation via NO mechanisms, it is possible that release of acetylcholine in the dermal space contributes to cutaneous vasodilation during a heat stress. To test this hypothesis, in seven subjects skin blood flow (SkBF) and sweat rate were simultaneously monitored over three microdialysis membranes placed in the dermal space of dorsal forearm skin. One membrane was perfused with the acetyleholinesterase inhibitor neostigmine (10 muM), the second membrane was perfused with the NO synthase inhibitor NI-nitro-L-arginine methyl ester (L-NAME; 10 mM) dissolved in the aforementioned neostigmine solution (L-NAME(Neo)), and the third membrane was perfused with Ringer solution as a control site. Each subject was exposed to similar to20 min of whole body heating via a water-perfused suit, which increased mean body temperature from 36.4 +/- 0.1 to 37.5 +/- 0.1degreesC (P < 0.05). After the heat stress, SkBF at each site was normalized to its maximum value, identified by administration of 28 mM sodium nitroprusside. Mean body temperature threshold for cutaneous vasodilation was significantly lower at the neostigmine-treated site relative to the other sites (neostigmine: 36.6 &PLUSMN; 0.1&DEG;C, L-NAME(Neo): 37.1 &PLUSMN; 0.1&DEG;C, control: 36.9 &PLUSMN; 0.1&DEG;C), whereas no significant threshold difference was observed between the L-NAME(Neo)-treated and control sites. At the end of the heat stress, SkBF was not different between the neostigmine-treated and control sites, whereas SkBF at the L-NAME(Neo)-treated site was significantly lower than the other sites. These results suggest that acetylcholine released from cholinergic nerves is capable of modulating cutaneous vasodilation via NO synthase mechanisms early in the heat stress but not after substantial cutaneous vasodilation., 2002年12月, 93, 6, 1947, 1951, 研究論文(学術雑誌)
  • 査読あり, 英語, ACTA PHYSIOLOGICA SCANDINAVICA, Sweating responses to a sustained static exercise is dependent on thermal load in humans, N Kondo; N Horikawa; K Aoki; M Shibasaki; Y Inoue; T Nishiyasu; CG Crandall, The purpose of this project was to test the hypothesis that internal temperature modulates the sweating response to sustained handgrip exercise. Ten healthy male subjects immersed their legs in 43 degreesC water for 30-40 min at an ambient temperatures of 30 degreesC and a relative humidity of 50%. Sweating responses to 50% maximal voluntary contraction isometric handgrip exercise (IH) were measured following the onset of sweating (i.e. following slight increases in internal temperature), and after more pronounced increases in internal temperature. Oesophageal temperature (T (es) ) was significantly lower during the first bout of exercise (37.54 +/- 0.07 degreesC) relative to the second bout (37.84 +/- 0.12 degreesC; P < 0.05). However, the increase in mean sweating rate (SR) from both the chest and forearm (non-glabrous skin) was significantly greater during the first IH bout relative to the second bout (P < 0.05). Increases in mean arterial blood pressure and palm SR (glabrous skin) did not differ significantly between exercise bouts, while heart rate and rating of perceived effort were significantly greater during the second bout of IH. As T (es) and mean skin temperature did not change during either bout of exercise, the changes in SR from non-glabrous skin between the bouts of IH were likely because of non-thermal factors. These data suggest that sweating responses from non-glabrous skin during IH vary depending on the magnitude of thermal input as indicated by differing internal temperatures between bouts of IH. Moreover, these data suggest that the contribution of non-thermal factors in governing sweating from non-glabrous skin may be greatest when internal temperature is moderate (37.54 degreesC), but has less of an effect after greater elevations in internal temperature (i.e. 37.84 degreesC)., 2002年08月, 175, 4, 289, 295, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Evidence that the human cutaneous venoarteriolar response is not mediated by adrenergic mechanisms, CG Crandall; M Shibasaki; TC Yen, The venoarteriolar response causes vasoconstriction to skin and muscle via local mechanisms secondary to venous congestion. The purpose of this project was to investigate whether this response occurs through a-adrenergic mechanisms. In supine individuals, forearm skin blood flow was monitored via laser-Doppler flowmetry over sites following local administration of terazosin (alpha(1)-antagonist), yohimbine (alpha(2)-antagonist), phentolamine (non-selective a-antagonist) and bretylium tosylate (inhibits neurotransmission of adrenergic nerves) via intradermal microdialysis or intradermal injection. In addition, skin blood flow was monitored over an area of forearm skin that was locally anaesthetized via application of EMLA (2.5% lidocaine (lignocaine) and 2.5% prilocaine) cream. Skin blood flow was also monitored over adjacent sites that received the vehicle for the specified drug. Each trial was performed on a minimum of seven subjects and on separate days. The venoarteriolar response was engaged by lowering the subject's arm from heart level such that the sites of skin blood flow measurement were 34 1 cm below the heart. The arm remained in this position for 2 min. Selective and non-selective a-adrenoceptor antagonism and presynaptic inhibition of adrenergic neurotransmission did not abolish the venoarteriolar response. However, local anaesthesia blocked the venoarteriolar response without altering a-adrenergic mediated vasoconstriction. These data suggest that the venoarteriolar response does not occur through adrenergic mechanisms as previously reported. Rather, the venoarteriolar response may due to myogenic mechanisms associated with changes in vascular pressure or is mediated by a nonadrenergic, but neurally mediated, local mechanism., 2002年01月, 538, 2, 599, 605, 研究論文(学術雑誌)
  • 査読あり, 英語, ACTA PHYSIOLOGICA SCANDINAVICA, Sweating response in physically trained men to sustained handgrip exercise in mildly hyperthermic conditions, S Yanagimoto; K Aoki; N Horikawa; M Shibasaki; Y Inoue; T Nishiyasu; N Kondo, To investigate the effects of physical training on heat loss response to sustained handgrip exercise (non-thermal factors), we compared the sweating response during isometric handgrip exercise to mild hyperthermia in physically trained and untrained subjects. Seven trained and untrained male subjects (maximal oxygen uptake 62.7 +/- 2.4 and 42.7 +/- 1.6 mL kg(-1) min(-1), respectively, P < 0.05) performed isometric handgrip exercises at 20, 35 and 50% maximal voluntary contraction (MVC) for 60 s. The study was conducted in a climatic chamber with a regulated ambient temperature of 35 &DEG;C and relative humidity of 50% to induce sweating response at rest by rising skin temperature without a marked change in internal temperature. Sublingual and mean skin temperatures (thermal factors) in both trained and untrained groups were essentially constant throughout all exercise intensities. Changes in heart rate, mean arterial blood pressure, and rating of perceived exertion with increased exercise intensity were similar in both groups, Sweating rate (SR) on the limbs (mean value of forearm and thigh) was significantly greater in the trained group than in the untrained group at 50% MVC (P < 0.05). In addition, the slopes of the relationship between increased SR and exercise intensity (% MVC) on the trunk (chest) and limbs were significantly greater in the trained group than in the untrained group (P < 0.05). Our results suggest that the sweating response caused by non-thermal factors against a background of changing thermal factors was enhanced by physical training. It is also thought that the enhanced sweating response may be especially evident on the limbs than on the trunk, such as improvement of sweating response associated with thermal factors., 2002年01月, 174, 1, 31, 39, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Baroreflex modulation of muscle sympathetic nerve activity during posthandgrip muscle ischemia in humans, J Cui; TE Wilson; M Shibasaki; NA Hodges; CG Crandall, To identify whether muscle metaboreceptor stimulation alters baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA, beat-by-beat arterial blood pressure (Finapres), and electrocardiogram were recorded in 11 healthy subjects in the supine position. Subjects performed 2 min of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 2.5 min of posthandgrip muscle ischemia. During muscle ischemia, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.001) during posthandgrip muscle ischemia (-201.9 +/- 20.4 units.beat(-1).mmHg(-1)) when compared with control conditions (- 142.7 +/- 17.3 units.beat(-1).mmHg(-1)). No significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. However, both curves shifted during postexercise ischemia to accommodate the elevation in blood pressure and MSNA that occurs with this condition. These data suggest that the sensitivity of baroreflex modulation of MSNA is elevated by muscle metaboreceptor stimulation, whereas the sensitivity of baroreflex of modulate heart rate is unchanged during posthandgrip muscle ischemia., 2001年10月, 91, 4, 1679, 1686, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Evidence for metaboreceptor stimulation of sweating in normothermic and heat-stressed humans, M Shibasaki; N Kondo; CG Crandall, 1. Isometric handgrip (IHG) exercise increases sweat rate and arterial blood pressure, and both remain elevated during post-exercise ischaemia. The purpose of this study was to identify whether the elevation in arterial blood pressure during post-exercise ischaemia contributes to the increase in sweating. 2. In normothermia, and during whole-body heating, 2 min IHG exercise at 40 % maximal voluntary contraction, followed by 2 min post-exercise ischaemia, was performed with and without bolus intravenous administration of sodium nitroprusside during the ischaemic period. Sodium nitroprusside was administered to reduce blood pressure during post-exercise ischaemia to pre-exercise levels. Sweat rate was monitored over two microdialysis membranes placed in the dermal space of forearm skin. One membrane was perfused with the acetyleholinesterase inhibitor neostigmine, while the other was perfused with the vehicle. 3. In normothermia, IHG exercise increased sweat rate at the neostigmine-treated site but not at the control site. Sweat rate remained elevated during post-exercise ischaemia even after mean arterial blood pressure returned to the pre-IHG exercise baseline. Subsequent removal of the ischaemia stimulus returned sweat rate to pre-IHG exercise levels. Sweat rate during postexercise ischaemia without sodium nitroprusside administration followed a similar pattern. 4. During whole-body heating, IHG exercise increased sweat rate at both neostigmine-treated and untreated sites. Similarly, regardless of whether mean arterial blood pressure remained elevated or was reduced during post-exercise ischaemia, sweat rate remained elevated during the ischaemic period. 5. These results suggest that sweating in non-glabrous skin during post-IHG exercise ischaemia is activated by metaboreflex stimulation and not via baroreceptor loading., 2001年07月, 534, 2, 605, 611, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Function of human eccrine sweat glands during dynamic exercise and passive heat stress, N Kondo; M Shibasaki; K Aoki; S Koga; Y Inoue; CG Crandall, The purpose of this study was to identify the pattern of change in the density of activated sweat glands (ASG) and sweat output per gland (SGO) during dynamic constant-workload exercise and passive heat stress. Eight male subjects (22.8 +/- 0.9 yr) exercised at a constant workload (117.5 +/- 4.8 W) and were also passively heated by lower-leg immersion into hot water of 42 degreesC under an ambient temperature of 25 degreesC and relative humidity of 50%. Esophageal temperature, mean skin temperature, sweating rate (SR), and heart rate were measured continuously during both trials. The number of ASG was determined every 4 min after the onset of sweating, whereas SGO was calculated by dividing SR by ASG. During both exercise and passive heating, SR increased abruptly during the first 8 min after onset of sweating, followed by a slower increase. Similarly for both protocols, the number of ASG increased rapidly during the first 8 min after the onset of sweating and then ceased to increase further (P > 0.05). Conversely, SGO increased linearly throughout both perturbations. Our results suggest that changes in forearm sweating rate rely on both ASG and SGO during the initial period of exercise and passive heating, whereas further increases in SR are dependent on increases in SGO., 2001年05月, 90, 5, 1877, 1881, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Effect of local acetylcholinesterase inhibition on sweat rate in humans, M Shibasaki; CG Crandall, ACh is the neurotransmitter responsible for increasing sweat rate (SR) in humans. Because ACh is rapidly hydrolyzed by acetylcholinesterase (AChE), it is possible that AChE contributes to the modulation of SR. Thus the primary purpose of this project was to identify whether AChE around human sweat glands is capable of modulating SR during local application of various concentrations of ACh in vivo, as well as during a heat stress. In seven subjects, two microdialysis probes were placed in the intradermal space of the forearm. One probe was perfused with the AChE inhibitor neostigmine (10 muM); the adjacent membrane was perfused with the vehicle (Ringer solution). SR over both membranes was monitored via capacitance hygrometry during microdialysis administration of various concentrations of ACh (1 x 10(-7)-2 M) and during whole body heating. SR was significantly greater at the neostigmine-treated site than at the control site during administration of lower concentrations of ACh (1 x 10(-7)-1 x 10(-3) M, P < 0.05), but not during administration of higher concentrations of ACh (1 x 10(-2)-2 M, P > 0.05). Moreover, the core temperature threshold for the onset of sweating at the neostigmine-treated site was significantly reduced relative to that at the control site. However, no differences in SR were observed between sites after 35 min of whole body heating. These results suggest that AChE is capable of modulating SR when ACh concentrations are low to moderate (i.e., when sudomotor activity is low) but is less effective in governing SR after SR has increased substantially., 2001年03月, 90, 3, 757, 762, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Effect of muscle mass on Vo(2) kinetics at the onset of work, S Koga; TJ Barstow; T Shiojiri; T Takaishi; Y Fukuba; N Kondo; M Shibasaki; DC Poole, The dependence of O-2 uptake ((V) over dot o(2)) kinetics on the muscle mass recruited under conditions when fiber and muscle recruitment patterns are similar following the onset of exercise has not been determined. We developed a motorized cycle ergometer that facilitated one-leg (1L) cycling in which the electromyographic (EMG) profile of the active muscles was not discernibly altered from that during two-leg (2L) cycling. Six subjects performed 1L and 2L exercise transitions from unloaded cycling to moderate [<ventilatory threshold (VT)] and heavy (>VT) exercise. The 1L condition yielded kinetics that was unchanged from the 2L condition [the phase 2 time constants (tau (1), in s) for <VT were as follows: 1L = 16.8 +/- 8.4 (SD), 2L = 18.4 +/- 8.1, P > 0.05; for >VT: 1L = 26.8 +/- 12.0; 2L = 27.8 +/- 16.1, P > 0.05]. The overall (V) over dot o(2) kinetics (mean response time) was not significantly different for the two exercise conditions. However, the gain of the fast component (the amplitude/work rate) during the 1L exercise was significantly higher than that for the 2L exercise for both moderate and heavy work rates. The slow-component responses evident for heavy exercise were temporally and quantitatively unaffected by the 1L condition. These data demonstrate that, when leg muscle recruitment patterns are unchanged as assessed by EMC analysis, on-transient ire, kinetics for both moderate and heavy exercise are not dependent on the muscle mass recruited., 2001年02月, 90, 2, 461, 468, 研究論文(学術雑誌)
  • 査読あり, 英語, Journal of Applied Physiology, Effects of exercise intensity on the sweating response to a sustained static exercise, 芝﨑学, 2000年03月, 88, 3, 1590-1596
  • 査読あり, 英語, ACTA PHYSIOLOGICA SCANDINAVICA, Relationship between skin blood flow and sweating rate in prepubertal boys and young men, M Shibasaki; Y Inoue; N Kondo; K Aoki; K Hirata, We sought the mechanisms in the maturation-related change of skin blood flow to heat stress. Eight prepubertal boys (7-11 years) and 11 young men (21-25 years) were exposed to a mild passive heating [by placing the lower legs and feet in a 42 degrees C water bath for 60 min while sitting in a neutral air condition (25 degrees C, 45% relative humidity)]. No age-related differences were observed for the increase in rectal temperature [0.61 +/- 0.05 (SEM) vs. 0.62 +/- 0.09 degrees C in the boys and men at the end of the passive heating, respectively], mean skin temperature (34.51 +/- 0.28 vs. 34.81 +/- 0.27 degrees C) or metabolic heat production (68 +/- 4 vs. 60 +/- 3 W m(-2)) during the passive heating. During the healing age-related differences in skin blood flow by laser Doppler flowmetry (LDF) and local sweating rate (m) over dot(sw)) varied by site; the boys had greater LDF on the chest and back, similar LDF on the forearm and thigh, lower (m) over dot(sw) on the chest and thigh, similar (m) over dot(sw) on the back, and greater (m) over dot(sw) on the forearm, compared with the men. The relationship between IDF and (m) over dot(sw) during the heat exposure was divided into three temporal phases: (a) an increase of LDF without an increase in (m) over dot(sw) (b) an increase of (m) over dot(sw) without the secondary increase of LDF, (c) a proportional increase of LDF and (m) over dot(sw). The increase of LDF in phase (a) and the slopes of the regression lines between the LDF and (m) over dot(sw) in phase (c) were significantly greater on the chest and back for the boys (P < 0.05), compared with the men, but not on the forearm and thigh. These results suggest: that the greater LDF observed on the trunk in the boys may be owing to a greater withdrawal of vasoconstrictor tone and a greater active vasodilation. Regional differences may exist in the maturation-related alterations in vasoconstriction and vasodilation., 1999年10月, 167, 2, 105, 110, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Kinetics of oxygen uptake during supine and upright heavy exercise, S Koga; T Shiojiri; M Shibasaki; N Kondo; Y Fukuba; TJ Barstow, Kinetics of oxygen uptake during supine and upright heavy exercise. J. Appl. Physiol. 87(1). 253-260, 1999.-It is presently unclear how the fast and slow components of pulmonary oxygen uptake (V overdot O-2) kinetics would be altered by body posture during heavy exercise [i.e., above the lactate threshold (LT)]. Nine subjects performed transitions from unloaded cycling to work rates representing moderate (below the estimated LT) and heavy exercise (V overdot O-2 equal to 50% of the difference between LT and peak Vet) under conditions of upright and supine positions. During moderate exercise, the steady-state increase in V overdot O-2 was similar in the two positions, but V overdot O-2 kinetics were slower in the supine position. During heavy exercise, the rate of adjustment of V overdot O-2 to the B-min value was; also slower in the supine position but was characterized by a significant reduction in the amplitude of the fast component, of V overdot O-2 without a significant slowing of the phase 2 time constant. However, the amplitude of the slow component was significantly increased, such that the end-exercise V overdot O-2 was the same in the two positions. The changes in V overdot O-2 kinetics for the supine vs. upright position were paralleled by a blunted response of heart rate at 2 min into exercise during supine compared with upright heavy exercise. Thus the supine position was associated with not only a greater amplitude of the slow component for V overdot O-2 but also, concomitantly, with a reduced amplitude of the fast component; this latter effect may be due, at least in part, to an attenuated early rise in heart rate in the supine position., 1999年07月, 87, 1, 253, 260, 研究論文(学術雑誌)
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGY-LONDON, Modulation of the thermoregulatory sweating response to mild hyperthermia during activation of the muscle metaboreflex in humans, N Kondo; H Tominaga; M Shibasaki; K Aoki; S Koga; T Nishiyasu, 1. To investigate the effect of the muscle metaboreflex on the thermoregulatory sweating response in humans, eight healthy male subjects performed sustained isometric handgrip exercise in an environmental chamber (35 degrees C and 50% relative humidity) at 30 or 45% maximal voluntary contraction (MVC), at the end of which the blood circulation to the forearm was occluded for 120 s. The environmental conditions were such as to produce sweating by increase in skin temperature without a marked change in oesophageal temperature. 2. During circulatory occlusion after handgrip exercise at 30% MVC for 120 s or at 45% MVC for 60 s, the sweating rate (SR) on the chest and forearm (hairy regions), and the mean arterial blood pressure were significantly above baseline values (P < 0.05). There were no changes from baseline values in the oesophageal temperature, mean skin temperature, or SR on the palm (hairless regions). 3. During the occlusion after handgrip exercise at 30% MVC for 60 s and during the occlusion alone, none of the measured parameters differed from baseline values. 4. It is concluded that, under mildly hyperthermic conditions, the thermoregulatory sweating response on the hairy regions is modulated by afferent signals from muscle metaboreceptors., 1999年03月, 515, 2, 591, 598, 研究論文(学術雑誌)
  • 査読あり, 英語, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, Mechanisms underlying the age-related decrement in the human sweating response, Y Inoue; M Shibasaki; H Ueda; H Ishizashi, To examine the mechanisms underlying the age-related decrement in the ability to sweat, seven older (64-76 years) and seven younger (20-24 years) men participated in a 60-min sweating test. The test consisted of placing the subject's lower legs in a water bath at 42 degrees C while sitting in a controlled environment of 35 degrees C ambient temperature and 45% relative humidity. The rectal (T-re) and skin temperatures, local sweating rates ((m) over dot(sw): on the forehead, chest, back, forearm and thigh) and the frequency of sweat expulsion (f(sw)) were measured during the test. No group difference was observed in the mean body temperature ((T) over bar(b)) throughout the passive heating, although the older men had a higher T-re and a lower mean skin temperature during the last half of the 60-min test. There were no group differences in the (T) over bar(b) threshold for sweating, although the time to the onset of sweating tended to be longer for the older men regardless of body site. The (m) over dot(sw) increased gradually for approximately 35 min after the start of heat exposure in the older men and for 30 min in the younger men and then reached a steady state. During the first half of the test, the older men had a significantly lower (m) over dot(sw) at all sites. During the last half of the test, only (m) over dot(sw) on the thigh was significantly lower in the older men than in the younger men. There was no group difference in the slope of f(sw) versus (T) over bar(b) tan indicator of the change in the central sudomotor response to thermal input). The slope of (m) over dot(sw) versus f(sw) tan indicator of the change in peripheral activity in response to central sudomotor changes) was significantly lower on the thigh in the older men, but there were no differences for the other sites. These results suggest that in older men the lower thigh (m) over dot(sw) observed during the last half of the heat test was possibly due to age-related modifications of peripheral mechanisms involving the sweat glands and surrounding tissues. It was not due to a change in the central drive to sudomotor function. Furthermore, the sluggish (m) over dot(sw) responses in the older men appear to have been related to age-related modifications of the sensitivity of thermoreceptors in various body regions to thermal stimuli. They may also involve lower sweat glands' sensitivity to cholinergic stimulus or sluggish vasodilatation, and do not reflect age-related changes in the central drive., 1999年01月, 79, 2, 121, 126, 研究論文(学術雑誌)
  • 査読あり, 英語, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, Relationship between skin blood flow and sweating rate, and age related regional differences, Y Inoue; M Shibasaki; K Hirata; T Araki, To examine the mechanisms and regional differences in the age-related decrement of skin blood flow, Il young (age 20-25 years) and 10 older (age 64-76 years) men were exposed to a mild heat stress by immersing their feet and lower legs in water at 42 degrees C for 60 min, while they were sitting in near thermoneutral conditions [25 degrees C and 45% relative humidity (rh)]. During the equilibrium period (25 degrees C and 45% rh) before the heat test, no group differences were observed in rectal (T-re) and mean skin (T-sk) temperatures or mean arterial pressure (MAP). During passive heating, T-sk was significantly lower in the older men 20 min after commencing exposure (P < 0.001), although there were similar increases in T-re in both groups. Exposure time and age did not affect MAP. The local sweating rate (liz,,) and the percentage change in skin blood flow by laser Doppler flowmetry (%LDF) relative to baseline values on the chest, back, forearm and thigh were significantly lower in the older men (P < 0.001), especially on the thigh. After starting the heat exposure, three temporal phases were observed in the relationship between %LDF and (m) over dot(sw) at most sites in each subject. In phase A, %LDF increased but with no increase in (m) over dot(sw). In phase B, (m) over dot(sw) increased but with no secondary increase in %LDF. Finally, in phase C, there were proportional increases in %LDF and (m) over dot(sw). The increase in %LDF in phase A was significantly lower on the forearm and thigh (P < 0.05) for the older men, but not on the chest and back. In phase C, the slopes of the regression lines between %LDF and (m) over dot(sw) were lower for the older men on the back (P < 0.03), forearm (P = 0.08) and thigh (P < 0.03), but not on the chest. These results would suggest that the age-related decrement in skin blood flow in response to passive heating may be due in part to a smaller release of vasoconstrictor tone and to less active vasodilatation once sweating begins. Regional differences exist in the impaired vasoconstriction and active vasodilatation systems., 1998年12月, 79, 1, 17, 23, 研究論文(学術雑誌)
  • 査読あり, 日本語, 人間工学, 赤外線透過ファイバを用いた非接触型鼓膜体温計の開発, 芝﨑学; 近藤徳彦; 森脇俊道, 1998年10月, 34, 5, 247-253
  • 査読あり, 英語, JOURNAL OF APPLIED PHYSIOLOGY, Continuous measurement of tympanic temperature with a new infrared method using an optical fiber, M Shibasaki; N Kondo; H Tominaga; K Aoki; E Hasegawa; Y Idota; T Moriwaki, The purpose of this study was to investigate the utility of an infrared tympanic thermometry by using an optical fiber for measuring tympanic temperature (T-ty). In the head cooling and facial fanning tests during normothermia, right T-ty, measured by this method (infrared-T-ty) and esophageal temperature (T-es) were not affected by decreased temple and forehead skin temperatures, suggesting that the infrared sensor in this system measured the infrared radiation from the tympanic membrane selectively. Eight male subjects took part in passive-heat-stress and progressive-exercise tests. No significant differences among infrared-T-ty, the left T-ty measured by thermistor (contact-T-ty), and T-es were observed at rest or at the end of each experiment, and there was no significant difference in the increase in these core temperatures from rest to the end. Furthermore, there were no significant differences in the core temperature threshold at the onset of sweating and slope (the relationship of sweating rate vs. infrared-T-ty and vs. contact-T-ty). These results suggest that this method makes it possible to measure T-ty accurately, continuously, and more safely., 1998年09月, 85, 3, 921, 926, 研究論文(学術雑誌)
  • 査読あり, 英語, ACTA PHYSIOLOGICA SCANDINAVICA, Regional differences in the effect of exercise intensity on thermoregulatory sweating and cutaneous vasodilation, N Kondo; S Takano; K Aoki; M Shibasaki; H Tominaga; Y Inoue, To investigate regional body differences in the effect of exercise intensity on the thermoregulatory sweating response, nine healthy male subjects (23.2 +/- 0.4 year) cycled at 35, 50 and 65% of their maximal O-2 uptake ((V) over dot o(2max)) for 30 min at an ambient temperature of 28.3 +/- 0.2 degrees C and a relative humidity of 42.6 +/- 2.4%. Local sweating rate ((m) over dot(sw)) on the forehead, chest, back, forearm and thigh increased significantly with increases in the exercise intensity from 35 to 50% (V) over dot o(2max) and from 50 to 65% (V) over dot o(2max) (P < 0.05). The mean values for the density of activated sweat glands (ASG) at 50 and 65% (V) over dot o(2max) at the five sites were significantly greater than at 35% (V) over dot o(2max). The mean value of the sweat output per gland (SGO) also increased significantly with the increase in exercise intensity (P < 0.05). The patterns of changes in ASG and SGO with an increase in exercise intensity differed from one region of the body to another. Although esophageal temperature (T-es) threshold for the onset of sweating at each site was not altered by exercise intensity, the sensitivity of the sweating response on the forehead increased significantly from 35 to 50 and 65% (V) over dot o(2max) (P < 0.05). The threshold for cutaneous vasodilation lend to increase with exercise intensity, although the exercise intensity did not affect the sensitivity (the slope in the relationship T-es vs. percentage of the maximal skin blood flow) at each site. T-es threshold for cutaneous vasodilation on the forearm was significantly higher at 65% (V) over dot o(2max) than at either 35 or 50% (V) over dot o(2max). but this was not observed at the other sites, such as on the forehead and chest. These results suggest that the increase in (m) over dot(sw) seen with an increasing intensity of exercise depends first on ASG, and then on SGO, and the dependence of ASG and SGO on the increase in (m) over dot(sw) differs for different body sites. In addition, there are regional differences in the T-es threshold for vasodilation in response to an increase in exercise intensity., 1998年09月, 164, 1, 71, 78, 研究論文(学術雑誌)
  • 査読あり, 英語, JAPANESE JOURNAL OF PHYSIOLOGY, Control of circadian variation in skin blood flow response to heat stress, K Aoki; N Kondo; M Shibasaki; S Takano; T Katsuura; K Hirata, Six male subjects had their lower legs immersed in water at 42 degrees C for 60 min at 4 different times of the day to study whether the skin blood flow response to passive heat stress shows circadian variation in the relationship between skin blood flow and local sweating rate. When skin blood flow was plotted against local sweating rate, three distinct phases were observed. Phase A, an increase in skin blood flow without sweating was maximal at night. But the slope of the regression line did not change over the day in Phase C. These findings suggest that there is circadian variation in the skin blood flow response before onset of sweating during passive heat stress. This variation might be related, in part, to the circadian rhythm in vasoconstrictor activity., 1998年02月, 48, 1, 95, 98, 研究論文(学術雑誌)
  • 査読あり, 英語, PHYSIOLOGY & BEHAVIOR, Circadian variation in skin blood flow responses to passive heat stress, K Aoki; N Kondo; M Shibasaki; S Takano; T Katsuura, To examine whether there is a circadian variation in skin blood flow response to passive heat stress and maximal skin brood flow, which was measured by local warming to 42 degrees C for 45 min, we studied six men at an ambient temperature of 28 degrees C at four different times of day [0400-0700 (morning), 1000-1300 (daytime), 1600-1900 (evening), and 2200-0100 hours (night)], each time of day being examined on separate days. Heat stress at rest was performed by immersing the legs below the knee in hot water (42 degrees C) for 60 min. The esophageal temperature (T-es) at rest was significantly higher in the evening than in the morning. The maximal skin blood flow (SkBF(max)) on both sites, back and forearm, did not show a significant difference among the four times of day. The variation in T-es thresholds for cutaneous vasodilation to heat stress was similar to the circadian rhythm in resting T-es. The relationship of the percentage of SkBF(max) (%SkBF) with T-es was significantly lower in the morning than in the evening. The results suggest that the maximal skin blood flow during local warming does not show variation over the day,but the sensitivity of vasodilation to passive heat stress shows a circadian variation. (C) 1998 Elsevier Science Inc., 1997年12月, 63, 1, 1, 5, 研究論文(学術雑誌)
  • 査読あり, 英語, ACTA PHYSIOLOGICA SCANDINAVICA, Circadian variation of sweating responses to passive heat stress, K Aoki; N Kondo; M Shibasaki; S Takano; H Tominaga; T Katsuura, The aim of present study was to examine whether sweating responses to passive heat stress change with the circadian rhythm of internal temperature. Six men bad their legs immersed in water at 42 degrees C for 60 min in an ambient temperature of 29 degrees C on four separate days. Experiments were conducted at four different times [06.00 h (morning), 12.00 h (daytime), 18.00 h (evening) and 24.00 h (night)]. We measured oesophageal temperature (T-oes), mean body temperature ((T) over bar(b)) local sweating rate ((m) over dot (sw)) on the forehead, back, forearm and thigh, the densities of activated sweat gland (ASG) on the back, forearm and thigh, and the frequency of sweat expulsion per minute (F-SW) which has been suggested to represent central sudomotor activity. Sweat gland output (SGO) on each site was calculated by dividing (m) over dot (sw) by ASG. ASG was significantly higher on the forearm than on the back and thigh, and SGO was significantly lower on the forearm than cn the back and thigh. However, ASG and SGO did not significantly change over the day. (T) over bar(b) and T-oes thresholds for the onset of sweating showed a significant change with both the temperature rhythms at rest prior to each procedure, while the slopes of the relationships F-SW - (T) over bar(b) and (m) over bar (sw) - F-SW showed no significant difference over the day. We suggest that the circadian variation of sweating response to passive heat stress is regulated by a central sudomotor mechanism rather than by sweat gland function., 1997年11月, 161, 3, 397, 402, 研究論文(学術雑誌)
  • 査読あり, 英語, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, Mechanisms of underdeveloped sweating responses in prepubertal boys, M Shibasaki; Y Inoue; N Kondo, To approach the mechanisms underlying the underdeveloped sweating responses of prepubertal boys. 8 boys (7-11 years old) and 11 men (21-25 years old) were exposed to a standard heat stress for 60 min. The test consisted of placing the subjects' lower legs into a 42 degrees C water bath while they sat in otherwise constant environmental conditions (ambient temperature 25 degrees C and 45% relative humidity). Rectal (T-re) and skin temperatures, local sweating rates (m(sw): on the chest, back, forearm and thigh) and the frequency of sweating expulsions (f(sw): as an indicator of central sudomotor activity) were measured during the test. During the passive heating. no group differences were observed for the increase in T-re, mean skin temperature and metabolic heat production. However, mean body temperature (<(T)over bar (b)>) during heating was significantly higher for the boys (P < 0.001) because of a higher baseline T-re. The boys had lower m(sw), on the chest (P < 0.004) and thigh (P < 0.001) during the latter half of the 60-min exposure compared to the young men, although a similar m(sw) was observed between the groups during the first half of the test. The group difference of m(sw) on the back was similar to that of the chest and thigh, but the difference was not significant (P=0.10). In contrast, the boys had a greater m(sw) on the forearm throughout the heating (P < 0.03). The slope of the m(sw) vs f(sw) relationship was compared to the men (P < 0.05), and the same tendency was observed for the back (but was not significant, P = 0.10). In contrast, no difference was observed between the groups for the slope of m(sw) vs f(sw) for the forearm. Furthermore, a lower sweat output per gland was also observed on the chest, back, and thigh in the boys (P < 0.01), but not on the forrarm. No group difference was observed for the slope of the f(sw) vs T-b relationship, These results suggest that the lower m(sw) observed in the prepubertal boys were due possibly to underdeveloped peripheral mechanisms, including the sweat glands and their surrounding tissues, rather than to an underdeveloped central drive activity related to sudomotor function. Regional differences map well exist in any underdeveloped peripheral mechanism associated with maturation., 1997年10月, 76, 4, 340, 345, 研究論文(学術雑誌)
  • 査読あり, 英語, Journal of Thermal Biology, Sweating responses to passive and active limb movements, 芝﨑学, 1997年10月, 22, 4/5, 351-356
  • 査読あり, 英語, ACTA PHYSIOLOGICA SCANDINAVICA, Effects of reduced muscle temperature on the oxygen uptake kinetics at the start of exercise, T Shiojiri; M Shibasaki; K Aoki; N Kondo; S Koga, The purpose of this study was to examine the effects of reduced muscle temperature (T-m) on gas exchange kinetics and haemodynamics al the start of exercise. Six male subjects performed moderate cycle exercise under reduced (C) and normal (N) T-m conditions. T-m and rectal temperature were significantly reduced by immersion in cold water (by 6.6 degrees C and 1.8 degrees C, respectively). The increases in oxygen uptake (VO2) and oxygen pulse (VO2/HR) during phase 1 (abrupt increase after the start of exercise) were significantly tower under C than under N. The time constant for O-2 under C (36.0 +/- 7.7 (SD) s) was significantly greater than under N (27.5 +/- 4.4 s); however. the time constants of cardiac output under C (38.3 +/- 16.6 s) and N (33.7 +/- 18.5 s) were similar. These results suggest that the slower VO2 on-response under reduced T-m conditions is caused by decreased O-2 extraction in working muscle and/or by impairment of oxidative reactions by reduced muscle temperature., 1997年04月, 159, 4, 327, 333, 研究論文(学術雑誌)
  • 査読あり, 英語, INTERNATIONAL JOURNAL OF BIOMETEOROLOGY, The effect of change in skin temperature due to evaporative cooling on sweating response during exercise, N Kondo; M Nakadome; KR Zhang; T Shiojiri; M Shibasaki; K Hirata; A Iwata, The purpose of this study was to investigate whether there are any effects of skin temperature changes on sweating response in the first few minutes of mild exercise. Six healthy males performed a bicycle exercise at 100 W (50 rpm) for 30 min under an ambient temperature of 23 degrees C (40% RH). Esophageal temperature (T-es), mean skin temperature ((T) over bar(sk)), local skin temperature at the lower left scapula (T-sl), local sweating rate ((M)over dot (sw)), and cutaneous blood flow by laser-Doppler flowmetry (LDF) were measured continuously. Although T-sl decreased markedly. just after the onset of sweating, (T) over bar(sk) did not change, (M)over dot (sw) did not increase constantly in the early stag es of exercise, and there was a temporary interruption in the increase of (M)over dot (sw). This interruption in sweating was affected by the rate of change in T-sl rather than by the absolute value of T-sl, since there was a positive and significant correlation between the time of the interruption in the increase of (M)over dot (sw) and the rate of decrease in T-sl (y=6.47x+0.04; r=0.86, P<0.05). The results suggest that sweating response in the early stages of exercise may be influenced by changes in local skin temperature due to evaporative cooling., 1997年04月, 40, 2, 99, 102, 研究論文(学術雑誌)
  • 査読あり, 英語, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, Thermoregulatory responses of prepubertal boys and young men during moderate exercise, M Shibasaki; Y Inoue; N Kondo; A Iwata, Seven prepubertal boys (aged 10-11 years) and eleven young men (aged 21-25 years), matched for skinfold thickness and maximal oxygen uptake (over dotVO(2max)) per unit of mass, cycled at an intensity of approximately 40% over dotVO(2max) for 45 min in a warm condition (30 degrees C, 45% relative humidity). During exercise no age-related differences were observed for the increases in rectal temperature (T-re) and heart rate (HR), although the absolute T-re and HR were significantly greater for the boys because of a higher initial baseline (P < 0.05). Total body sweating rate [181 (SEM 12) vs 245 (SEM 12) g . m(-2). 45 min(-1) P < 0.002] and local sweating rates (over dotm(sw)) on chest, back, and forearm were significantly lower for the boys (P < 0.001), as was metabolic heat production [203 (SEM 9) vs 276 (SEM 9) W . m(-2); P < 0.01]. The lower over dotm(sw) in the boys was due to a lower output per activated sweat gland, even though they had a higher activated sweat gland density regardless of site. In contrast, cutaneous blood flow by laser Doppler flowmetry (LDF) in the boys was significantly greater on the chest and back, compared to the men (P < 0.003). The age-related differences in cutaneous vascular conductance (CVC) were more marked because of lower mean arterial pressure in the boys during exercise. However, forearm LDF and CVC were significantly lower for the boys (P < 0.008). No significant differences in LDF among sites were observed for the boys, whereas for the men LDF on the forearm was significantly greater than on the chest and back (P < 0.01). The boys showed lower mean skin temperatures (especially on the back and chest despite greater increments of LDF) after starting to sweat, whereas the men remained unchanged, suggesting that the heat loss on the trunk in the boys was promoted by greater increments of LDF despite lower over dotm(sw), compared to the young men. It was concluded that during moderate exercise in an air temperature at 30 degrees C, prepubertal boys could thermoregulate as efficiently as young men by greater vasodilatation on their trunk despite lower over dotm(sw). Furthermore regional differences may exist in the maturation-related modification of vasodilatation., 1997年03月, 75, 3, 212, 218, 研究論文(学術雑誌)
  • 査読あり, 英語, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, Regional differences in age-related decrements of the cutaneous vascular and sweating responses to passive heating, Y Inoue; M Shibasaki, Ten older (aged 64-76 years) and ten younger (aged 20-24 years) healthy men were exposed to a standard heat stress [by placing the lower legs and feet in a water bath at 42 degrees C while sitting in a controlled environment (ambient temperature 35 degrees C and 45% relative humidity) for 60 min]. During passive heating, the rectal temperature of the older men was significantly greater (P <0.05) and mean skin temperature was Lower (P <0.001), compared to the younger men. Skill blood flow by laser Doppler flowmetry (LDF) was significantly lower on the chest and thigh for the older men (P <0.001), but forehead LDF did not differ between the groups. The percentages of total LDF in the older men to total LDF in the younger men for the last 30 min were 99%, 58% and 50% on the forehead, chest and thigh, respectively. The age-related differences in LDF responses mirrored cutaneous vascular conductances (CVC), since no group and time effects were observed in mean arterial blood pressure during the test. During the last 30 min the local sweat rates (m(sw)) on the back and thigh were significantly lower for the older men (P <0.02), but not on forehead, chest and forearm, although the older men had lower m(sw) during the first 30 min exposure regardless of site (P <0.03). The percentages of total LDF in the older men to total LDF in the younger men during the last 30 min were 105%, 99%, 63%, 106% and 88% on the forehead, chest, thigh, forearm, and back, respectively. During the latter half of the exposure, the older men had similar LDF, CVC and m(sw) the forehead, lower on LDF and CVC and a similar m(sw) on the chest, and lower LDF, CVC and m(sw) on the thigh, compared to the younger men. These results suggest firstly that regional differences exist in the age-related decrement of cutaneous vasodilatation as well as sweat gland function, secondly that the age-related decrement in cutaneous vascular function may precede a decrement in sweat gland function, and thirdly that the successive decrements may develop sequentially From the lower limbs to the upper body, and head., 1996年08月, 74, 1-2, 78, 84, 研究論文(学術雑誌)
  • 査読あり, 英語, JAPANESE JOURNAL OF PHYSIOLOGY, The influence of work loads on regional differences in sweating rates, S Takano; N Kondo; M Shibasaki; K Aoki; Y Inoue; A Iwata, The influence of work loads (20, 40 and 60% V-O2max) on regional differences in sweating rates was investigated in six healthy male students, The ratios of local sweating rate (m(sw)) on the chest and back to estimated total sweating rate (mean m(sw) of four sites examined X body surface area) at 20% work load were significantly greater than those on the forearm and forehead, whereas the ratio on the forehead at 60% work load was greater than at the other sites, The ratios on the forearm at 40 and 60% work loads were significantly greater than at 20% work load. The regional differences in sweating rates change with the increase in work load as seen by the greater variation in the ratios of m(sw) on each site at 20% work load compared with 40 and 60% work loads. The results indicate that redistribution of this sweat activity to whole body or head with the rise in work load induces favorable conditions for evaporation and controlling brain temperature., 1996年04月, 46, 2, 183, 186, 研究論文(学術雑誌)
  • 査読あり, 英語, RESPIRATION PHYSIOLOGY, Kinetics of oxygen uptake and cardiac output at onset of arm exercise, S Koga; T Shiojiri; M Shibasaki; Y Fukuba; Y Fukuoka; N Kondo, Pulmonary oxygen uptake (Vover dot(O2)) kinetics at onset of exercise is reported to be slower for arm than for leg exercise. This could be attributed to reduced cardiac output (Qover dot) or reduced arteriovenous O-2 content difference or both. To test this, Vover dot(O2), mean tissue oxygen consumption (Vover dot(O2T)), and Qover dot kinetics in arm cranking were compared with corresponding values found in leg cycling. The increase in Vover dot(O2) during phase 1 (abrupt increase after onset of exercise) was less in arm than in leg exercise, suggesting that immediate Qover dot adjustments to arm exercise were less pronounced. Mean response times (MRT, the relative rates at which a steady state was attained) for Vover dot(O2), Vover dot(O2T), and Qover dot were prolonged during arm exercise. The MRT of Vover dot(O2) in arm exercise at a given blood lactate increase was higher than in leg exercise. The delayed Vover dot(O2) kinetics in arm exercise might be due to delayed Qover dot kinetics and higher anaerobic glycolysis occurring early during arm exercise., 1996年02月, 103, 2, 195, 202, 研究論文(学術雑誌)
  • 査読あり, 英語, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY, THE EFFECT OF DIURNAL-VARIATION ON THE REGIONAL DIFFERENCES IN SWEATING AND SKIN BLOOD-FLOW DURING EXERCISE, K AOKI; T SHIOJIRI; M SHIBASAKI; S TAKANO; N KONDO; A IWATA, The aim of the present study was to examine changes in the control of heat-dissipation responses to exercise associated with the diurnal variation in core temperature from the viewpoint of the regional response patterns. We studied seven men during exercise on a cycle ergometer at 100 W for 40 min at 25 degrees C at 0630 (morning) 1630 (evening) hours on 2 separate days. Oesophageal temperature (T-oes), local skin temperature, local sweating rate (m(sw)) on the forehead, back, forearm and thigh, and skin blood flow by laser Doppler flowmeter (LDF) on the back and forearm were measured continuously. The T-oes at rest was significantly higher in the evening than in the morning, the difference averaging approximately 0.4 degrees C (P < 0.05). The T-oes thresholds for each site in m(sw) and that for back in LDF were significantly different between the two times of day (P < 0.05). The change in T-oes thresholds for sweating and vasodilatation for morning and evening were similar to T-oes at rest. Although m(sw) on the forehead was significantly higher in the morning than in the evening, m(sw) on the back was significantly higher in the evening than in the morning (P < 0.05). Total local sweating rate (m(sw,tot)) for each site during exercise was significantly higher on the forehead than on the forearm in the morning, and on the back than on the forearm in the evening, respectively (P < 0.05). The results would suggest that the diurnal variation of heat-dissipation responses to exercise is influenced not only by a central controlling mechanism but also by changes in the regional differences., 1995年08月, 71, 2-3, 276, 280, 研究論文(学術雑誌)
  • 日本語, 日本生気象学会雑誌, 日本生気象学会, 暑熱負荷時における二酸化炭素分圧(PCO2)変化に対する外・内頸動脈血流反応, 平澤 愛; 佐藤 耕平; 岡崎 和伸; 宮本 忠吉; 小河 繁彦; 芝崎 学, 2012年10月, 49, 3, S50, S50
  • 日本語, 日本生気象学会雑誌, 日本生気象学会, 暑熱負荷における脳血流量低下に対する外頸動脈血流量の関係性, 佐藤 耕平; 岡崎 和伸; 宮本 忠吉; 平澤 愛; 小河 繁彦; 芝崎 学, 2012年10月, 49, 3, S74, S74
  • 日本語, 体力科学, (一社)日本体力医学会, 起立ストレス時の脳循環応答, 小河 繁彦; 平澤 愛; 岡崎 和伸; 宮本 忠吉; 佐藤 耕平; 定本 朋子; 芝崎 学, 2014年12月, 63, 6, 579, 579
  • 日本語, 日本生気象学会雑誌, 日本生気象学会, 高体温時における下肢陰圧負荷時の脳血流量反応, 野間 あゆみ; 佐藤 耕平; 小河 繁彦; Crandall Craig; 芝崎 学, 2015年10月, 52, 3, S32, S32
  • 日本語, 宇宙航空環境医学, 日本宇宙航空環境医学会, 下肢陰圧負荷時の脳血流反応, 芝崎 学; 佐藤 耕平; 小河 繁彦, 2014年12月, 51, 4, 70, 70
  • その他, PLOS ONE, Modality differences in ERP components between somatosensory and auditory Go/No-go paradigms in prepubescent children, Hiroki Nakata; Miho Takezawa; Keita Kamijo; Manabu Shibasaki, We investigated modality differences in the N2 and P3 components of event-related potentials (ERPs) between somatosensory and auditory Go/No-go paradigms in eighteen healthy prepubescent children (mean age: 125.9±4.2 months). We also evaluated the relationship between behavioral responses (reaction time, reaction time variability, and omission and commission error rates) and amplitudes and latencies of N2 and P3 during somatosensory and auditory Go/No-go paradigms. The peak latency of No-go-N2 was significantly shorter than that of Go-N2 during somatosensory paradigms, but not during auditory paradigms. The peak amplitude of P3 was significantly larger during somatosensory than auditory paradigms, and the peak latency of P3 was significantly shorter during somatosensory than auditory paradigms. Correlations between behavioral responses and the P3 component were not found during somatosensory paradigms. On the other hand, in auditory paradigms, correlations were detected between the reaction time and peak amplitude of No-go-P3, and between the reaction time variability and peak latency of No-go-P3. A correlation was noted between commission error and the peak latency of No-go-N2 during somatosensory paradigms. Compared with previous adult studies using both somatosensory and auditory Go/No-go paradigms, the relationships between behavioral responses and ERP components would be weak in prepubescent children. Our data provide findings to advance understanding of the neural development of motor execution and inhibition processing, that is dependent on or independent of the stimulus modality., 2021年11月08日, 16, 11, e0259653, e0259653, 研究論文(学術雑誌)
  • その他, PLOS ONE, Effects of passive heat stress and recovery on human cognitive function: An ERP study, Hiroki Nakata; Ryusuke Kakigi; Manabu Shibasaki, Using event-related potentials (ERPs), we investigated the effects of passive heat stress and recovery on the human cognitive function with Flanker tasks, involving congruent and incongruent stimuli. We hypothesized that modulation of the peak amplitude and latency of the P300 component in ERP waveforms would differ with task difficulty during passive heat stress and recovery. Subjects performed the Flanker tasks before (Pre), at the end of whole body heating (Heat: internal temperature increase of ~1.2°C from the pre-heat baseline), and after the internal temperature had returned to the pre-heat baseline (Recovery). The internal temperature was regulated by a tube-lined suit by perfusing 50°C water for heat stress and 25°C water for recovery immediately after the heat stress. Regardless of task difficulty, the reaction time (RT) was shortened during Heat rather than Pre and Recovery, and standard deviations of RT (i.e., response variability) were significantly smaller during Heat than Pre. However, the peak amplitudes of the P300 component in ERPs, which involved selective attention, expectancy, and memory updating, were significantly smaller during Heat than during Pre, suggesting the impairment of neural activity in cognitive function. Notably, the peak amplitudes of the P300 component were higher during Recovery than during Heat, indicating that the impaired neural activity had recovered after sufficient whole-body cooling. An indicator of the stimulus classification/evaluation time (peak latency of P300) and the RT were shortened during Heat stress, but such shortening was not noted after whole-body cooling. These results suggest that hyperthermia affects the human cognitive function, reflected by the peak amplitude and latency of the P300 component in ERPs during the Flanker tasks, but sufficient treatment such as whole-body cooling performed in this study can recover those functions., 2021年07月20日, 16, 7, e0254769, e0254769, 研究論文(学術雑誌)
  • 日本語, 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, オリンピック・パラリンピック研究委員会, 諸岡 晴美; 芝崎 学, 2016年, 57, 11, 858, 858
  • その他, 一般社団法人日本家政学会研究発表要旨集, 一般社団法人 日本家政学会, 周期的局所温度刺激による温度感覚, 芝崎 学, 目的 日常生活における温度環境は動的に変化し,温度感覚も同様に動的に変化する.動的な温度環境下において,既存のスケールで被験者の温度感覚を表現するにはいくつかの問題があるため,我々は痛み感覚スケールに利用される視覚的アナログスケール(VAS)を応用して,動的な温度変化に対する温熱感覚評価を試みている.しかし,VASも主観的評価スケールであり,温度感覚の客観的・定量的評価には脳機能計測による評価が必要であるが,温度感覚の評価は確立されていない.本研究では現在の脳機能計測機器で温度感覚評価を可能にするための実験アプローチの構築を目的とする. 方法 非利き腕側の前腕内側部に温冷感覚刺激装置を貼付し,5つの異なる安静時皮膚温(10,18,28,33,36°C)から周期的局所温度刺激を実施し,VASで温度感覚を評価した.また,温度に依存しない温度感覚を与えるため,1wt%のメントールを皮膚に塗布し,効果の現れる5分後からどうようの実験を実施した。 結果 個人差はあるものの,周期間で温度感覚に差は認められなかった.温度の振幅は5°Cに統一していたが,VASの振幅は安静時皮膚温が高くなるほど大きくなった.メントールによる増幅も高温時でのみ認められた.皮膚温上昇時下降時で温度感覚の再現性が異なり,安静時皮膚温が33°Cよりも低い場合は下降時に,高い場合は温度上昇時に温度変化に対して高い反応性を示した., 2015年, 67, 137, 137
  • 日本語, 体力科学, The Japanese Society of Physical Fitness and Sports Medicine, 低酸素環境下における脳血流の動脈血二酸化炭素分圧に対する応答特性:換気化学反射の影響, 小河 繁彦; 中原 英博; 上田 信也; 岡崎 和伸; 芝崎 学; 宮本 忠吉, 2014年, 63, 1, 111, 111
  • 日本語, 日本生気象学会雑誌, Japanese Society of Biometeorology, 214 加齢が発汗・脈管反応の身体部位差に及ぼす影響, 井上 芳光; 芝崎 学; 上田 博之; 平田 耕造, 1994年, 31, 3, 139, 139
  • 日本語, デサントスポーツ科学, (公財)石本記念デサントスポーツ科学振興財団, 高体温時の認知機能低下の機能的磁気共鳴画像法による空間的神経ネットワーク評価, 芝崎 学; 佐伯 崇; 若原 卓; 北條 達也; 中田 大貴, 暑熱環境下運動時には高体温による中枢性疲労によって運動パフォーマンスが低下する。同様に認知機能が低下することが報告されている。本研究では機能的磁気共鳴画像法(fMRI)を用いて、暑熱負荷中の認知機能テスト時の空間的神経ネットワークを評価した。18名の健康な若年者が参加し、暑熱負荷前および外耳道温が1.1℃上昇した後に、2種類の認知機能テスト(Go/No-go課題およびFlanker課題)をMRI室内で実施し、反応時間および神経活動領域を測定した。反応時間はいずれの課題においても暑熱負荷によって短縮したがエラー率に暑熱による影響はほとんど認められなかった。脳活動部位は。両課題とも暑熱負荷によって補足運動野および運動前野等の運動関連領域、背外側前頭前野が活発化し、Flanker課題では視覚刺激の認知処理に関与する視覚野と側頭連合野の活動が高まった。これらの結果は同じ課題を遂行する場合であっても、暑熱負荷によって脳活動への負担が高まったことを示唆するものである。(著者抄録), 2018年05月, 39, 84, 93
  • 査読あり, 英語, JOURNAL OF PHYSIOLOGICAL SCIENCES, Blood flow response to carbon dioxide in human internal and external carotid arteries during hyperthermic condition, Ai Hirasawa; Manabu Shibasaki; Rio Sakamoto; Kohei Sato; Kazunobu Okazaki; Tadayoshi Miyamoto; Shigehiko Ogoh, 2013年, 63, S264, S264, 研究論文(学術雑誌)

MISC

  • 査読無し, 日本語, 日本衣服学会, 加齢に伴う体温調節機能の変化と衣服への提案, 芝﨑学, 2015年03月, 58, 2, 60, 70
  • 査読無し, 日本語, 月刊せんい, 体温調節に関する研究の動向 ?子どもと高齢者?, 芝﨑学, 2014年08月, 67, 8, 475-480
  • 査読無し, 日本語, 体育の科学, 暑熱環境下における体温調節, 芝﨑学, 2014年07月, 64, 7, 461-465
  • 査読無し, 日本語, 発汗学, 発汗研究の新たなツール, 芝﨑学, 2013年04月, 20, 1, 21-24
  • 査読無し, 日本語, 発汗学, 高齢者の発汗反応, 芝﨑学, 2012年12月, 19, 2, 52-55
  • 査読無し, 日本語, 日本生気象学会雑誌 日本生気象学会50周年記念誌, 若手から見た生気象学-生理学分野から-, 芝﨑学, 2012年03月, 59-61
  • 査読無し, 日本語, 発汗学, 運動時の発汗反応-皮内マイクロダイアリシスと発汗に関する研究への応用-, 芝﨑学, 2009年12月, 16, 2, 58-62
  • 査読無し, 日本語, 体育・スポーツ科学, 人における運動時の熱放散反応, 近藤徳彦; 芝﨑学; 青木健, 2000年, 9, 1-13
  • 日本語, デサントスポーツ科学, 石本記念デサントスポーツ科学振興財団事務局, 暑熱環境の違いが運動時のヒト脳認知機能に及ぼす影響, 中田 大貴; 大城 岬; 難波 真理; 芝﨑 学, 2017年05月, 38, 17, 27
  • 日本語, 体力科學, 日本体力医学会, 466.暑熱下における皮膚血流量反応の性周期・性差, 井上 芳光; 小倉 幸雄; 浅見 尚子; 上田 博之; 石指 宏通; 芝崎 学; 近藤 徳彦, 2000年12月01日, 49, 6, 899, 899
  • 日本語, 体力科學, 日本体力医学会, 464.Normothermia時の発汗反応に影響する非温熱性要因, 芝崎 学; 近藤 徳彦; 井上 芳光, 2000年12月01日, 49, 6, 898, 898
  • 日本語, 体力科學, 日本体力医学会, 498.筋代謝受容器からの求心性入力が発刊反応に及ぼす影響, 近藤 徳彦; 富永 寛隆; 芝崎 学; 堀川 直幹; 西保 岳, 1998年12月01日, 47, 6, 951, 951
  • 日本語, 体力科學, 日本体力医学会, 356.発汗開始時と定常状態時の発汗反応に及ぼす非温熱性要因の影響, 堀川 直幹; 芝崎 学; 富永 寛隆; 近藤 徳彦, 1998年12月01日, 47, 6, 880, 880
  • 日本語, 体力科學, 日本体力医学会, 596.アイソメトリックハンドグリップ運動に対する発汗反応, 富永 寛隆; 芝崎 学; 堀川 直幹; 近藤 徳彦, 1997年12月01日, 46, 6, 910, 910
  • 日本語, 体力科學, 日本体力医学会, 490.発汗量の増加に伴う汗腺数と単一汗腺あたりの汗出力の変化, 近藤 徳彦; 芝崎 学; 富永 寛隆; 堀川 直幹, 1997年12月01日, 46, 6, 857, 857
  • 日本語, 体力科學, 日本体力医学会, 356.暑熱環境下における児童の皮膚血流量, 芝崎 学; 井上 芳光; 上田 博之; 近藤 徳彦; 岩田 敦, 1994年12月01日, 43, 6, 684, 684
  • 日本語, 日本生気象学会雑誌, ニコチンがラットの脳波および海馬血流量に及ぼす影響, 近藤 直美; 芝崎 学; 吉本 光佐; 三木 健寿, 2006年10月01日, 43, 3, S40
  • 日本語, 体力科學, 日本体力医学会, 392. 運動時の発汗反応に貢献するセントラルコマンドと代謝性の筋からの求心性入力(体液・内分泌), 芝崎 学; 近藤 徳彦, 2003年12月01日, 52, 6, 910, 910
  • 日本語, デサントスポ-ツ科学, 石本記念デサントスポ-ツ科学振興財団事務局, マイクロダイアリシスを用いた汗腺機能の評価, 芝崎 学; Grandall Graig G.; 近藤 徳彦, 2000年, 21, 51, 58
  • 日本語, デサントスポ-ツ科学, 石本記念デサントスポ-ツ科学振興財団事務局, 人の熱放散反応を改善する可能性がある温度以外の入力, 近藤 徳彦; 富永 寛隆; 芝崎 学, 2000年, 21, 85, 94
  • 日本語, デサントスポ-ツ科学, 石本記念デサントスポ-ツ科学振興財団事務局, 光ファイバを用いた赤外線鼓膜体温計の有用性, 近藤 徳彦; 芝崎 学; 堀川 直幹, 1999年, 20, 177, 183
  • 日本語, 人間科学研究, 神戸大学, 子供の体温調節特性, 芝崎 学; 近藤 徳彦; 井上 芳光, 1995年, 3, 1, 99, 108
  • 日本語, 日本運動生理学雑誌, 日本運動生理学会事務局, 33. 運動時における思春期前児童の体温調節反応特性, 芝崎 学; 井上 芳光; 近藤 徳彦, 1995年, 2, 1, 48, 48
  • 査読無し, 英語, MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, LIPPINCOTT WILLIAMS & WILKINS, Cognitive Task Impairs Dynamic Cerebral Autoregulation During Normoxia And Hypoxia., Shigehiko Ogoh; Hiroaki Nakata; Tadayoshi Miyamoto; Manabu Shibasaki, 2017年05月, 49, 5, 65, 65, 研究発表ペーパー・要旨(国際会議)
  • 査読無し, 英語, MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, LIPPINCOTT WILLIAMS & WILKINS, Human Cognitive Function During Acute Hypoxic Exposure, Manabu Shibasaki; Shigehiko Ogoh; Tadayoshi Miyamoto; Hiroki Nakata, 2017年05月, 49, 5, 241, 241, 研究発表ペーパー・要旨(国際会議)
  • 査読無し, 英語, MEDICINE AND SCIENCE IN SPORTS AND EXERCISE, LIPPINCOTT WILLIAMS & WILKINS, Human Cognitive Function During Acute Hypoxic Exposure, Manabu Shibasaki; Shigehiko Ogoh; Tadayoshi Miyamoto; Hiroki Nakata, 2015年05月, 47, 5, 241, 241, 研究発表ペーパー・要旨(国際会議)

書籍等出版物

  • 次世代自動車の熱マネジメント, 技術情報協会, 日本語, 学術書, ISBN:978-4-86104-819-7
  • 生理学, 南江堂, 彼末, 一之; 全国柔道整復学校協会, 2020年03月, xvi, 262p, 日本語, その他, 9784524240296, cinii_books
  • 被服学事典, 朝倉書店, 牛膓, ヒロミ; 布施谷, 節子; 佐々井, 啓; 増子, 富美; 平田, 耕造; 石原, 久代; 藤田, 雅夫; 長山, 芳子, 第1章1.4人体生理 1.4.3体温調節,1.4.5重力(姿勢変化)と体温調節,1.4.6運動と体温調節, 2016年10月, ix, 490p, 図版 [4] p, 日本語, その他, 9784254620153, cinii_books
  • Fluid Balance, Hydration, and Athletic Performance, CRC Press, 芝﨑学, 分担, 2016年01月, 33-58, 英語, 査読無し, その他, 9781482223286
  • ニュー運動生理学 II, 真興交易(株)医書出版部, 宮村 実晴, 「運動と体温」3.皮膚における体温調節 193-201頁, 2014年09月, 冊, 日本語, その他, 9784880038865, cinii_books
  • イラスト社会・環境と健康, 東京教学社, 朝山正己,稲葉 裕,池田若葉,井谷 徹,北川 章,黒澤美智子,芝崎 学,城 憲秀,竹谷 淳,新川美紀,本多恭子, 2011年04月, ix, 295p, 日本語, その他, 9784808260316, cinii_books
  • 運動生理学のニューエビデンス, 真興交易(株)医書出版部, 宮村, 実晴, 「運動と体温」2.末梢調節 329-336頁, 2010年11月, 462p, 日本語, その他, 9784880038469, cinii_books
  • 体温調節システムとその適応, ナップ, 井上芳光; 近藤徳彦, 第1章IV汗腺活動と皮膚血管,第2章IV体温上昇と血圧調節 37-51頁,106-116頁, 2010年11月, xiii, 304p, 日本語, その他, 9784931411005, cinii_books
  • カラダの百科事典, 丸善, 日本生理人類学会, 「汗って?」,420-424頁, 2009年09月, xxii, 724p, 日本語, その他, 9784621081723, cinii_books
  • Nonthermoregulatory modification of sweating and skin blood flow Exercise, Nutrition, and Environmental Stress Vol. 4, Cooper Publishing Group, 芝﨑学, 2005年, 227-243頁, 英語, 査読無し, その他
  • Pulmonary and muscle oxygen uptake kinetics at the onset of exercise Exercise, Nutrition, and Environmental Stress Vol. 3, Cooper Publishing Group, 芝﨑学, 2003年, 63-84頁, 英語, 査読無し, その他
  • 運動時の体温調節システムとそれを修飾する要因, ナップ, 平田, 耕造; 井上, 芳光; 近藤, 徳彦, 汗腺と皮膚血管の調節, 2002年09月, x, 251p, 日本語, その他, 9784931411319, cinii_books
  • これでなっとく使えるスポーツサイエンス, 講談社, 征矢, 英昭; 本山, 貢; 石井, 好二郎; 講談社サイエンティフィク, 複数, 2002年06月, viii, 173p, 日本語, その他, 4061531182, cinii_books
  • Strategy for preventing heat illness in children and in the elderly Exercise, Nutrition, and Environmental Stress Vol. 2, Cooper Publishing Group, 芝﨑学, 2002年, 239-271頁, 英語, 査読無し, その他
  • 新運動生理学, 真興交易医書出版部, 宮村, 実晴, 「運動と体温」2.皮膚血管と汗腺の活動 258-265頁, 2001年, 2冊, 日本語, その他, 4880036692, cinii_books
  • The effect of density of activated sweat glands and sweat output per gland on the change in sweating rate The 1997 Nagano symposium on sports sciences, Cooper Publishing Group, 芝﨑学, 1998年, 英語, 査読無し, その他
  • 人間科学計測ハンドブック, 技報堂出版, 日本生理人類学会計測研究部会, 「発汗」201-211頁, 1996年10月, 631p, 日本語, その他, 4765500292, cinii_books
  • 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-, 54-55, 2021年04月20日, その他, その他
  • 次世代自動車の熱マネジメント, 技術情報協会, 技術情報協会, 76-83, 2020年12月25日, 649p, 日本語, その他, 9784861048197, cinii_books

Works(作品等)

  • Neural and non-neural modulators of skin blood flow and sweating in humans., 2006年09月, 2010年10月
  • Neural and non-neural modulators of skin blood flow and sweating in humans., 2006年09月, 2010年10月
  • 暑熱負荷時における血圧変動による皮膚血流量調節, 2006年06月, 2006年07月
  • 機械受容器反射の発汗および皮膚血流量に対する影響, 2003年09月, 2003年10月
  • Effect of mechanoreflex on sweating and skin blood flow during recovery of dynamic exercise, 2003年09月, 2003年10月
  • 暑熱環境下運動中の発汗および皮膚血流量に対するセントラルコマンドの影響, 2002年05月, 2002年07月
  • Effect of central command on sweating and skin blood flow during isometric handgrip exercise in the heat stressed human, 2002年05月, 2002年07月
  • 暑熱暴露時における皮膚血管反応に対するコリン作動性神経から放出されるアセチルコリンの影響, 2000年08月, 2000年09月
  • Modulation of cutaneous vasodilation during heat stress due to acetylcholine released from cholinergic nerves, 2000年08月, 2000年09月
  • 掌握運動中の発汗反応における代謝受容器反射の影響, 1999年08月, 1999年09月
  • Effect of metaboreflex on sweating during isometric handgrip exercise, 1999年08月, 1999年09月

受賞

  • 久野寧記念賞, 日本生理学会, 2006年

共同研究・競争的資金等の研究課題

  • 基盤研究B, 2019年, 2022年, 研究分担者, 超高齢者社会の健康寿命を訴求したユニバーサル仕様の衣服設計−生体情報を指標に−
  • 基盤研究B, 2018年, 2022年, 研究代表者, 暑熱環境下運動時の中枢性および末梢性疲労による筋出力調節および循環調節への影響
  • 基盤研究B, 2015年, 2017年, 研究分担者, 乳児型発汗サーマルマネキンの開発へ向けて 不感蒸散および発汗の同時再現装置の構築
  • 萌芽研究, 2012年, 2014年, 研究代表者, 擬似的温冷感による快適性および予防医学的衣料の開発
  • 基盤研究B, 2011年, 2013年, 研究代表者, 熱中症予防を目的とした機能的ウェア開発のための生理機能評価
  • 若手研究B, 2009年, 2010年, 研究代表者, 暑熱環境下における起立耐性と血流調節
  • 基盤研究A, 2008年, 2010年, 研究分担者, 温熱的環境適応能の老化過程の解明と老化遅延策の構築
  • 若手研究B, 2005年, 2006年, 研究代表者, 暑熱環境下における起立性ストレス時の皮膚血管調節
  • 基盤研究B, 2003年, 2005年, 研究分担者, 高齢者・冷え症者に配慮した温熱環境に関する研究 −冷暖房使用環境下の日常生活行動と生理量との関連からの検討−
  • 萌芽研究, 2003年, 2004年, 研究代表者, 入眠を促進する足踵温度コントロール-湯たんぽの効果を生理学的に見直す-
  • 若手研究A, 2002年, 2003年, 研究代表者, 動的運動初期の体温調節反応に関与する筋からの求心性入力
  • 基盤研究B(展開), 2000年, 2001年, 研究分担者, ヒトの生理学的適応能力の計測技術の体系化
  • 奨励研究A, 2000年, 2001年, 研究代表者, 運動時の発汗神経活動における非温熱要因の影響
  • 日本学術振興会特別研究員 特別研究員奨励費, 1998年, 研究代表者, 人間の体温調節に関する研究
  • 2019年04月, 2022年03月, 研究代表者, 機能性ウェアへの水分散布による蒸発性熱放散促進および紫外線散乱による温熱的快適性向上, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 基盤研究(B), 2019年04月, 2022年03月, 19H01616, 研究分担者, 超高齢社会の健康寿命を訴求したユニバーサル仕様の衣服設計―生体情報を指標に―, 諸岡 晴美; 三野 たまき; 芝崎 学; 佐藤 真理子; 深沢 太香子, 日本学術振興会, 科学研究費助成事業 基盤研究(B), 京都女子大学, 17810000, 13700000, 4110000, 令和元年度は,高齢者や障害者の身体機能の低下を支援する「ユニバーサル仕様」の衣服設計について,下記の各観点から研究を進めた. A.温熱的アプローチ:年齢による温熱感覚を把握するために,若・中年齢女性について身体各部位における温度感受性について温冷覚計を用いて測定・解析を行った結果,下肢の温度感受性に年齢差が認められた.また,脊髄損傷者における暑熱負荷時の体温調節および血液循環反応について,水循環服の水温を調節することで測定を行った.一方、高齢者の暑熱感受性の鈍さが熱中症を引き起こす原因になる場合がある.そこで,安価で簡便な方策として冷却ベストを開発し,32℃の環境下でその効果を確認した.さらに,パラスポーツの一つであるゴールボール競技の腰プロテクター付きパンツについて,温熱的観点から適切な素材を検討した. B.圧的アプローチ:つまずきによる転倒が原因で寝たきりになる高齢者が多く,つまずきを未然に防ぐことは健康寿命を延伸する上において非常に重要であることから,三次元動作解析,重心動揺,姿勢保持の観点から検討し,具体的な靴下設計のための設計指針を導出した.また,むくみ軽減靴下や体脂肪を効率よく燃焼させるランニングパンツを作製し,着用実験にてその効果を検証した.さらに,前述したゴールボール競技における腰プロテクターについて,圧衝撃性の観点からも検討を行った.一方,アクティブシニアのための筋疲労軽減タイプコンプレッション型ランニングパンツの設計を目的として,筋電図・心電図の測定から現流通品の課題点を明らかにした. C.触的アプローチ:褥瘡は,人体に加わる圧力分布と強度・持続時間,殿部の皮膚状態,座面の湿度が重要な要因である.パラスポーツの一つであるシッティングバレーボール(SV)の車椅子座面素材を検討するために,SV競技者に対してアンケート調査を行い,座面素材の接触圧や蒸れの程度を測定した.
  • 基盤研究(B), 2018年04月, 2022年03月, 18H03166, 研究代表者, 暑熱環境下運動時の中枢性および末梢性疲労による筋出力調節および循環調節への影響, 芝崎 学; 大高 千明; 藤原 素子; 中田 大貴, 日本学術振興会, 科学研究費助成事業 基盤研究(B), 奈良女子大学, 17160000, 13200000, 3960000, 暑熱環境下で運動すると、快適な環境下での運動と比較して、疲労感を感じやすく、生体への負担も大きいため、運動継続時間が短縮する。暑熱環境下運動時の疲労は末梢性だけでなく、体温の過剰な上昇による中枢性疲労によっても誘発されることが報告されている。本研究プロジェクトでは、これらの両疲労が筋出力調節および循環調節に与える影響を客観的指標から評価することを目的としている。 脳活動指標として、注意力や運動遂行および抑制機能を評価するP300、運動開始に伴う随伴陰性変動(CNV)および運動関連電位(MRCP)を用いて実験を実施し、セントラルコマンドを定量化するために検討している。初年度の実験で運動開始の関連する電位変化において、提示方法および負荷方法の改善の必要性がみられた。昨年度は事象関連電位を主にプロトコルを設定したため、運動初期の循環応答を検討するのには少し問題点がみられた。また、単純に暑熱負荷による高体温の影響のみを検討したため、効果を得やすかったが、末梢性疲労の影響を検討するためには負荷方法を再検討する必要があると思われた。そこで、本年度は上腕の小筋群を対象とするのではなく、脚部の大筋群を対象とした実験系ができるように、当初計画から少し変更して負荷装置を製作することとしていた。進捗状況に記述するように、計画を修正する必要があり、繰り返しの認知課題による長時間の脳活動によっても中枢性疲労の実験を優先した。 昨年度から継続した実験結果と合わせて、論文として発表できる研究を2つ、次年度に繋がる予備実験を2つ遂行することができた。今春に予定されていた国際学会で2演題発表する予定にしていたが、渡航禁止に加えて学会も中止となったために、発表できていない。しかし、その内の1つの研究で、昨年度から継続した実験結果では日本生気象学会において発表賞を受賞した。
  • 2020年04月, 2021年03月, 研究分担者, 暑熱環境下における皮質脊髄路の興奮性の検討, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 2018年04月, 2019年03月, 研究分担者, 暑熱環境下の運動による脱水がヒト脳認知機能に及ぼす影響, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 2017年04月, 2018年03月, 研究代表者, 高体温時の認知機能低下の機能的磁気共鳴画像法による空間的神経ネットワーク評価, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 基盤研究(B), 2015年04月, 2018年03月, 15H02889, 研究分担者, 乳児型発汗サーマルマネキンの開発へ向けて 不感蒸散および発汗の同時再現装置の構築, 深沢 太香子; 芝崎 学; 栃原 裕; Kuklane Kalev; Tourula Marjo, 日本学術振興会, 科学研究費助成事業 基盤研究(B), 京都教育大学, 17550000, 13500000, 4050000, 乳児の形態および熱産生・熱放散を模擬した発汗サーマルマネキンの開発を将来的目標とし,本研究では,乳児人体からの不感蒸散と温熱性発汗を模擬する,不感蒸散再現装置と温熱性発汗再現装置を構築した.調査より,乳児人体からの不感蒸散量は約8 g/m2hで,温熱性発汗量は最大でも約25 g/m2h と少量であることがわかった.性能評価実験より,不感蒸散再現装置は,乳児体表からの不感蒸散をよく再現することが確認された.また,温熱性発汗再現装置も,拍出された汗が体表ですぐに蒸発する現象をよく再現することが確認された.これらより,本研究で開発した系は,発汗サーマルマネキン構築に応用可能であることが示された., url
  • 2016年04月, 2017年03月, 研究分担者, 暑熱環境の違いが運動時のヒト認知機能に及ぼす影響, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 2015年04月, 2016年03月, 研究代表者, 暑熱環境下における聴覚情報処理および高次認知機能の評価, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 挑戦的萌芽研究, 2012年04月, 2015年03月, 24650468, 研究代表者, 疑似的温冷感による快適性および予防医学的衣料の開発, 芝崎 学; 根岸 裕子; 久保 博子, 日本学術振興会, 科学研究費助成事業 挑戦的萌芽研究, 奈良女子大学, 3770000, 2900000, 870000, 空調や衣服による物理的な温度変化ではなく、TRPチャネル刺激による温度感受性を操作することによって擬似的に皮膚温度感覚の快適性を亢進することで快適な生活環境ならびに熱中症予防策を構築するために、客観的な温度感覚評価方法の確立を試みた。温度惹起にはメントールを用い、温度感覚変化と皮膚血管反応から最適なアプローチ方法を検討した。脳波計を用いた刺激方法によってメントールによってAδの活性を増大することを確認した。周期的温度刺激方法によって、最適な温度感覚評価領域を示すことができ、メントールによってその反応が増幅されることが確認された。, url
  • 基盤研究(B), 2011年04月, 2014年03月, 23300265, 研究代表者, 熱中症予防を目的とした機能的ウェア開発のための生理機能評価, 芝崎 学; 森本 恵子, 日本学術振興会, 科学研究費助成事業 基盤研究(B), 奈良女子大学, 17550000, 13500000, 4050000, 熱中症対策のための機能性ウェアの提案という視点から研究プロジェクトを企画し,今回は赤外線・紫外線に対する温度感覚と皮膚血流反応および熱失神に関与する血流調節を検討するための4つの研究を計画し,実行した:①温度感覚スケールの改良,②皮膚温度感覚と皮膚血流変化,③紫外線による温度感覚変化,④暑熱曝露時の血流分布.①の成果を②と③で検証し,その有用性を確認した.今後の脳機能評価に関する研究アプローチへの応用が期待できる.また,④では機能性ウェア開発への生理的アプローチの指針を示すことができた., url
  • R01, 2006年09月, 2012年08月, 研究分担者, Neural and non-neural modulators of skin blood flow and sweating in humans., Principal Investigator: Craig G. Crandall, National Heart, Lung, and Blood Institute, National Institutes of Health, Univ. Texas, Southwestern Medical Center at Dallas & IEEM Presbyterian Hospital of Dallas
  • 若手研究(B), 2009年04月, 2011年03月, 21790225, 研究代表者, 暑熱環境下における起立耐性と血流調節, 芝崎 学, 日本学術振興会, 科学研究費助成事業 若手研究(B), 奈良女子大学, 4290000, 3300000, 990000, 高体温時の起立耐性低下に起因する下肢の血流量調節に関する実験を実施した。皮膚の血管収縮反応性を皮内マイクロダイアリシスによる外因性ノルエピネフリンの多濃度投与および細静動脈反射で評価し、静脈コンプライアンスおよび血管外への漏出量を大腿部加圧および下肢陰圧装置を用いて評価した。高体温時に、これらのパラメータは低下した。高温期に静脈コンプライアンスおよび血管外への漏出量が増加し、起立耐性も低下した。, url
  • 基盤研究(A), 2008年04月, 2011年03月, 20247035, 研究分担者, 温熱的環境適応能の老化過程の解明と老化遅延策の構築, 井上 芳光; 古賀 俊策; 近藤 徳彦; 上田 博之; 石指 宏通; 芝崎 学; 近江 雅人, 日本学術振興会, 科学研究費助成事業 基盤研究(A), 大阪国際大学, 46150000, 35500000, 10650000, ヒトの環境適応能の老化機序を解明するため,全身協関的視点から検討した結果,以下のことが示された.体温調節機序は男女とも,入力系→効果器系→出力系→中枢系の順序で老化し,下肢の汗腺機能は下腿が大腿より,下肢の後面が前面より早期に老化する.老化に伴い非温熱性要因の複合的入力に対する反応が小さくなる.若年者でみられた熱放散反応の性差は老化によって小さくなる.高齢者の汗腺機能の夏へ向けての亢進が若年者より遅延し,また,暑熱下の起立耐性に影響する皮膚血流量調節の関与は高齢者では小さく,夏季における高齢者の血栓形成は若年者より促進される.体温調節機序の入力系や出力系に対して老化遅延策は見出せなかったが,効果器系では運動習慣の確立が有効である., url
  • 2008年04月, 2009年03月, 研究代表者, 妊娠・授乳期の健康管理ポータブルデバイスの開発, JST, 地域イノベーション創出総合支援事業「シーズ発掘試験」, 奈良女子大学
  • 2007年04月, 2008年03月, 研究代表者, 暑熱環境下における運動時の循環・体温・体液調節の相互作用に関する研究, (財)中冨健康科学財団, 国際研究交流助成, 奈良女子大学
  • 若手研究(B), 2005年04月, 2007年03月, 17790162, 研究代表者, 暑熱環境下における起立性ストレス時の皮膚血管調節, 芝崎 学, 日本学術振興会, 科学研究費助成事業 若手研究(B), 奈良女子大学, 3400000, 3400000, 起立性ストレスを負荷すると、内臓や筋または皮膚などの血管は収縮し、血圧の維持に貢献する。暑熱環境下では、深部体温の上昇によって皮膚血管が拡張する。深部体温がかなり上昇した場合、心拍出量の約50%が末梢皮膚循環へ分配されることが報告されている。そのため、暑熱環境下における起立性ストレス時の血圧維持に対して、皮膚血管の収縮は非常に大きな役割を担っていることが考えられる。先行研究によって、暑熱環境下における皮膚血管収縮反応には、皮膚血管拡張神経活動の低下と皮膚血管収縮神経活動の亢進の両方が関与していることが報告されている。しかし、後者のメカニズムは、減弱されている可能性が示唆されている。 本研究の目的は、暑熱環境下における皮膚血管収縮反応の減弱メカニズムを明らかにすることである。被験者は健康な若年男性または女性、約10名を対象とする。実験1では、局所加温によって皮膚血管を拡張させ、実験2では、血管拡張性物質を皮内マイクロダイアリシスより投与する。 実験1:局所温度制御装置によって、皮膚温を40℃にコントロールし、1つのマイクロダイアリシスプローブにはリンゲル液を、もう1つにはL-NAMEと血管拡張物質であるアデノシンを投与する。血流量が安定した後、ノルエピネフリンによる用量作用テストを行う。 実験2:一酸化窒素ドナーであるニトロプルシッドをマイクロダイアリシスプローブより、別のもう1つのプローブよりニトロプルシッドとL-NAMEを、さらに別のプローブよりアデノシンを連続的に投与する。血流量が安定した後、ノルエピネフリンによる用量作用テストを行う。 実験1では、局所加温にともなうNO由来の皮膚血管拡張の個人差が大きく、L-NAMEによってNO由来の血管拡張を抑制した分をアデノシンで補うことを試みたが、皮膚血流量をクランプすることが困難であったために、途中で断念した。実験2では、アデノシンによる皮膚血管拡張レベルを基準としてニトロプルシッドの濃度を変化させたため、安定したベースラインが得られた。ノルエピネフリンによる用量曲線は、アデノシン投与側よりもニトロプルシッド側でノルエピネフリンの高濃度側へ移動した。
  • 基盤研究(B), 2003年04月, 2006年03月, 15300245, 研究分担者, 高齢者・冷え性者に配慮しだ温熱環境に関する研究-冷暖房使用環境下の日常生活行動と生理量との関連からの検討, 久保 博子; 磯田 則生; 芝崎 学, 日本学術振興会, 科学研究費助成事業 基盤研究(B), 奈良女子大学, 13600000, 13600000, 研究目的に沿って、寒さや暑さに強い者は健康への被害を考えないような環境でも、温熱的に弱者である寒さや暑さに弱い者や高齢者など身体機能の衰えた者では、体調を崩すなど影響を受けるため、より配慮した環境を提供することが望ましい。このため高齢者や冷え症者を対象として人工気候室において、温熱的快適性や、温熱環境に対する生理的反応・心理的反応に関する詳細な検討を行った。 内容は、平成15年〜17年にかけてアンケート調査1件、実測調査3件、一連の実験室実験3件を行い、成果はそれぞれより関連の深い学会にて、各年度にそれぞれ数回の報告を行っていたが、それらをまとめ、詳細な検討を行った。 それぞれ、アンケート調査および実測調査からは、冷え性者や高齢者の生活実態および冷暖房使用の実態が明らかになり、実験室実験からは、温熱的な弱者の生理的・心理的な特徴がある程度明らかになった。日常生活行動との関連についても、考察を行い、高齢者では躯幹部の皮膚温は低め、末梢部の皮膚温は高めで特に、低温選択群の被験者の中には身体の熱生産量以上に室温を低下させて放熱量が多くなり、温熱的中立が保てなかったり、低温環境において舌下温が低下したものもいた。また、実験で得られた被験者の温熱的個人差よりも、住宅性能などにより温熱環境に差が見られたが、暖かい環境を好む被験者は着衣が多いなど、着衣量や冷暖房の使用率などの住まい方で補っている状況が冬期も夏期も認められた。 これらの結果をもとに、高齢者、青年群を低温選択群、中温選択群、高温選択群の3群に分類し、それぞれの快適範囲を提案した。また、重回帰分析を用いて、要因分析を行い、冷えやすさが影響していることを明らかにした。
  • 萌芽研究, 2003年04月, 2005年03月, 15650151, 研究代表者, 入眠を促進する足踵温度コントロール-湯たんぽの効果を生理学的に見直す-, 久保 博子; 芝崎 学; 磯田 則生; 久保 博子, 日本学術振興会, 科学研究費助成事業 萌芽研究, 奈良女子大学, 3300000, 3300000, 本プロジェクトは、医・工学系ではなく生活科学系から、製品開発の新しいコンセプトの提供とその可能性を示しうるデータの収集を第一の目的とする。入眠に焦点をおき、入眠時の生理学的および物理学的パラメータから、入眠を促進するパラメータを評価し、どうすれば入眠を促進することができるのか、そこに新しい製品開発コンセプトを見出すことを試みる。昨今見直されてきつつある湯たんぽは、足踵を効果的に暖めるため、これに注目して入眠を促進する製品の開発に役立てることを目的とした。 昨年度行った予備実験として行った昼寝実験より求めた、実際的な快適な足部加温条件をもとにして、終夜睡眠実験をおこなった。 健康な青年女子(大学生)6名を被験者として採用して、冬期の寝具・寝衣条件で、冬期の室内環境として、入床前安静時18℃、入床前60分より起床時まで15℃50%で夜間の睡眠実験を行った。寝床内暖房条件として、条件1:加温なし、条件2:湯たんぽ湯温55℃、条件3:電気あんか低温で終夜使用、条件4:電気あんか高温で足底皮膚温が30℃になるまで使用の4条件とした。睡眠時には、脳波、心拍数、体動量、直腸温、皮膚温などを測定し、入床前後には心理申告を求めた。 その結果、(1)足底部加温器具による加温は、足部皮膚温が速やかに上昇し、直腸温の低下を促し、入眠促進効果があることが示唆された。(2)足部が適切に加温器具接触してない場合は足部皮膚温の上昇が速やかではなかったが、入眠時に高めの温度設定条件であった条件2、4においては、比較的安定した入眠促進効果がみられた。その後の温度低下の影響はほとんどみられなかった。(3)足部加温器の使用では、寝床内温度が既往の報告にある快適温度範囲に達する前に置いても速やかな入眠効果がみられた。
  • 若手研究(A), 2002年04月, 2004年03月, 14704020, 研究代表者, 動的運動初期の体温調節反応に関与する筋からの求心性入力, 芝崎 学, 日本学術振興会, 科学研究費助成事業 若手研究(A), 奈良女子大学, 15600000, 12000000, 3600000, これまでの研究において、運動時の発汗反応には、セントラルコマンドや筋の代謝受容器からの入力が影響することを報告してきた。しかし、これまでの研究アプローチは、静的な運動を対象としており、動的な運動時における発汗反応に対しては不明な点が残されている。特に、筋の機械受容器からの入力が発汗反応に影響するか否かについては、静的な運動時においても明らかにされていない。本研究では、昨年度に引き続き、動的運動時の発汗反応に影響する非温熱性要因に注目し、その中でも本年は機械受容器反射の役割について検討した。 健康な男性被験者を対象として、20分間で心拍数が毎分135拍程度になるような運動を実施した後に、今回開発した仰臥位で受動的な運動が可能なタンデム自転車を用いた受動的運動回復と、無運動の安静回復をそれぞれ異なる日に実施し、その運動回復期間中の発汗および皮膚血管反応を比較検討した。実験は、本学環境制御室内で実施され、被験者は事前に運動負荷テストを実施し、そのデータをもとに運動負荷を設定した。また、本実験は2日に分けて実施され、体温調節の日内リズムを考慮して、2日とも同時間帯に実施した。 受動的運動を確認するために、左右の大腿直筋の筋電図を測定した。20分間の運動前にOWの能動的な自転車運動を実施し、運動回復期の受動的運動時の筋電図に能動的運動時のようなバーストが確認されると被験者にリラックスするように指示した。運動回復期の食道温および皮膚温の変化に両回復モードによる差はみられなかった。受動的運動時の発汗量は、安静回復のそれよりも高い値を示したが、皮膚血管コンダクタンスは両回復に差はみられなかった。これらの結果より、運動回復期において筋からの機械的刺激は発汗反応を促進するが、皮膚血管反応には影響しないことが示唆された。
  • 2001年04月, 2002年03月, 研究代表者, 異なる被服圧が有酸素運動能力に及ぼす影響, 石本記念デサントスポーツ科学振興財団, 奈良女子大学
  • 基盤研究(B), 2000年04月, 2002年03月, 12554039, 研究分担者, ヒトの生理学的適応能力の計測技術の体系化, 古賀 俊策; 近藤 徳彦; 福場 良之; 井上 芳光; 芝崎 学; 塩尻 智之, 日本学術振興会, 科学研究費助成事業 基盤研究(B), 神戸芸術工科大学, 13100000, 13100000, 身体運動への適応能力を研究する上で必要な生理的計測肢術(有酸素運動能力,酸素運搬機能と筋肉の酸素利用機能の計測技術)を検討した。特に,超音波ドップラー法による心拍出量と活動筋の血流量,近赤外分光測定法による酸素利用機能の計測技術を検討した.結果:心拍出量と活動筋血流量の連続測定が可能となり、運動の開始時においては酸素摂取応答に比べて,中心および末梢循環の応答がより速いことが確認された。したがって、酸素摂取応答の規定要因は酸素運搬能力ではなく,運動筋自体の酸素利用能力と考えられる.さらに、運動筋微小循環の酸素分圧(動物実験)とヒトにおける酸素化状態の測定結果を比較し、運動開始時における運動筋の酸素利用能力が、運動筋内部の酸素能に依存すると推測された。また,呼吸変動が酸素摂取量の応答特性に与える影響を調べた。 体温調節の動的特性を調べるために循環スーツ内温度を急激に変化させた場合、皮膚温や皮膚血流量も急激に変化した。特に,末梢部の変化が大きく,スーツ温下降の方が生体反応の追従性がより早い.本法により体温調節機構の動的特性を十分に評価できると考えられた.また、昨年度にヒトの皮膚血流量を準定量的に測定できることを認めたレーザードップラー式血流画像化装置で下肢温浴時の胸・人腿の皮膚血流量を高齢者と若年成人とで比較検討した。その結果は、老化が下肢から始まるという我々の先行研究結果を支持する。温熱負荷中にコリン作動性神経から放出されるアセチルコリンは、一酸化窒素(NO)メカニズムを介して能動的皮膚血管拡張に関係する可能性がある。マイクロダイアリシス法を用いた結果から、コリン作動性アセチルコリンは、初期の皮膚血管拡張には関連するが、皮膚血管が十分に拡張した後にはほとんど効果がないことが示された。
  • 奨励研究(A), 2000年04月, 2002年03月, 12780024, 研究代表者, 運動時の発汗神経活動における非温熱要因の影響, 芝崎 学, 日本学術振興会, 科学研究費助成事業 奨励研究(A), 奈良女子大学, 2100000, 2100000, 動的運動時に深部体温や皮膚温などの温熱性要因の上昇に先行して、発汗量が増大することが報告されている。動的運動時における神経性の入力として、セントラルコマンドと筋からの求心性入力が挙げられ、おそらくこれらのいずれかもしくは両方が運動初期の発汗反応に関与しているものと考えられる。本年度の研究では、咋年度の研究結果を踏まえて、動的運動時の発汗反応に影響する非温熱要因の中でも、特に筋からの求心性入力の影響について注目して検討した。 健康な男女の若年成人の被験者を対象とし、3強度の自転車運動負荷、および中強度運動時の両大腿部への加圧(60mmHg)および無加圧時の発汗反応を検討した。実験は、環境制御室内で実施され、本実験前の簡易テストで、各被験者の無毛部の発汗が軽運動では発現するが、安静状態で発現しない環境温度を確認し、制御室内の温度を調節した。 いずれの実験においても、運動中、深部体温および皮膚温は上昇しなかった。3強度の運動負荷実験では、前腕部および手掌部の発汗量は、運動強度の増加に伴い、心拍数や平均血圧と同様に増加した。これに対し、大腿部への加圧・無加圧実験では、加圧することによって、平均動脈血圧と同様に前腕部の発汗量は無加圧時よりもより大きく増加したが、手掌部の発汗量および心拍数は運動中上昇するものの加圧・無加圧による差は認められなかった。 これらの結果は、動的運動時にも非温熱性要因によって発汗活動は賦活されることを示しており、動的運動時の発汗は運動強度に影響されること、また加圧による筋からの求心性入力増大が無毛部の発汗反応を賦活する可能性が示唆された。
  • 2000年04月, 2001年03月, 研究代表者, マイクロダイアリシスを用いた発汗機能の評価, 石本記念デサントスポーツ科学振興財団, 奈良女子大学

Ⅲ.社会連携活動実績

1.公的団体の委員等(審議会、国家試験委員、他大学評価委員,科研費審査委員等)

  • 2011年01月, 2015年06月, 学協会
  • 日本体力医学会, 評議員, 2015年08月, 9999年, 学協会
  • 日本体力医学会, 将来構想計画委員会, 2015年09月, 9999年, 学協会
  • 2008年04月, 9999年, 学協会
  • 日本生気象学会, 理事, 2017年04月, 9999年, 学協会
  • 日本体力医学会, 近畿地方会理事, 2017年03月, 9999年, 学協会
  • 日本生理学会, 英文誌編集委員, 2011年01月, 9999年, 学協会
  • 日本生理学会, 評議委員, 2008年04月, 9999年, 学協会
  • 日本生気象学会, 評議委員, 2008年04月, 9999年, 学協会


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