| Project/Area Number |
11670059
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Shimane Medical University |
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Principal Investigator |
SHIDO Osamu Shimane Medical University, Physiology, Professor, 医学部, 教授 (40175386)
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| Co-Investigator(Kenkyū-buntansha) |
YAMASAKI Hiroshi Shimane Medical University, Physiology, Instructor, 医学部, 助手 (20304280)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | heat acclimation / cold acclimation / time memory / circadian rhythm / Fos protein / thermoregulation / core temperature / 温度馴化 / FOS蛋白 / 暑熱曝露 / ストレス / 慨日リズム |
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| Research Abstract |
After daily temperature stimulus for 4 〜 5 hours limited to a fixed time, time memory for temperature stimuli can be formed in the thermoregulatory system of rats and humans and, according to the memory, thermoregulatory functions alter during the period when subjects were previously exposed to heat without actual temperature stress. We investigated the Fos protein expression in various nuclei in the brain in rats after subjection to daily timed temperature stress. Rats, kept in a 12 : 12 LD cycle, were exposed to heat or cold only in the last half of the dark phase of the day. Control rats were not exposed to temperature stress. After a 12-day temperature exposure schedule, they were anesthetized and their brains were removed in the first half (M), at the middle (N) or in the last half of the dark phase (A) of a day. The brain samples were then sliced and immunohistochemical staining for Fos protein was performed. In the control and cold-exposed rats, the number of Fos-positive cells in the preoptic anterior hypothalamus increased during the periods N and A compared to that of the period M, while it did not increase in the period A in the heat-exposed rats. The number of Fos-positive cells in the suprachiasmatic nucleus did not change in the dark phase in the controls, whereas it gradually decreased in the dark phase in the heat- and cold-exposed rats. A similar pattern of Fos expression was seen in the paraventricular nucleus. There were no differences in the Fos expression in the supraoptic, supramammilary and lateral mammilary nuclei among the groups. It seems that timed daily temperature stimuli alter the pattern of day-night variations of neuronal activities in the several brain nuclei in rats.
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