1997 Fiscal Year Final Research Report Summary
Study of behavioral rhythm disturbances after chronic stress exposures.
| Project/Area Number |
08670094
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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 | University of Occupational and Environmental Health |
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Principal Investigator |
ENDO Yutaka University of Occupational and Environmental Health, Department of Physiology, School of Medicine, Assistant professor, 医学部, 講師 (90194050)
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| Co-Investigator(Kenkyū-buntansha) |
SONE Fumio Department of Clinical Pathophysiology, University of Occupational and Environme, 産業保健学部, 講師 (80269050)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Chronic stress / Circadian rhythm / Behavior / Body temperature / Corticosterone / Melatonin / Sleep-wakefulness / Communication box |
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| Research Abstract |
In order to examine the influences of a long-term stress exposure on circadianrhythm, we measured behavioral and hormonal parameters over a day in stress-exposed and control rats. In the stress sessions, male rats were exposed to foot shock (FS group) or sociopsychological stress (non foot shock stress, NFS group) induced by the communication box, or immobilization stress (Immo group) for 1 hour in a day over 12 weeks.
Chronic stress exposure did not significantly influence circadian rhythms of motor activity, feeding and drinking, plasma melatonin level and sleep-wakefulness patterns in rats in all stress groups. However, only in rats in NFS group, chronic stress exposure caused a higher in the mesor of body temperature rhythm, that is, stress-enduced hyperthermia, but did not change the amplitude and the acrophase of it. Further, chronic stress exposures decreased in the amplitude of corticosterone rhythm due to a decrease in circadian peak in all stress groups. The present study demonstrates that a long-term stress exposure does not impair circadian behavioral and hormonal rhythms other than corticosterone rhythm and also shows that only emotional stress exposure could induce a hyperthermia over a long-term after the termination of stress exposure.
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