| Project/Area Number |
15530470
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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 |
Experimental psychology
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| Research Institution | Shiga University |
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Principal Investigator |
IBUKA Nobuo Shiga University, Dep.of Psychology, Vice President, 理事 (70110757)
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| Project Period (FY) |
2003 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | stress / seasonality / photoperiod / testes / body weight / Syrian hamster / 体重 / 臨界日長 / 光周反応性 / 脳下垂体 / 精巣発達 / 体重発達 / 時間生物学 / 光周期 / シベリアハムスター |
|---|
| Research Abstract |
Two experiments were performed to clarify the significance on seasonality of stress in Syrian hamsters. The first experiment was conducted to investigate the effect of living in enriched environments on stress tolerance in hamsters under decreasing photoperiods. Stress was produced by unpredictable deprivation of food on 30% of the days during the 12-week decreasing photoperiods. We hypothesized that living in the enriched environments alleviates stress, and thus prevents the detrimental effects by stress on testicular and body development in hamsters under decreasing photoperiods. The present finding indicated that the animals living in enriched environments gained their weights more than their controls, and eluded the loss of body weight produced by stress. Our result also showed that living in enriched environment tended to stimulate testicular development and prevent the suppressive effect by stress on testicular development under decreasing photoperiod.
The second experiment was co
… More
nducted to clarify the effect of hypophysectomy on stress tolerance in the Syrian hamster using indicators of body weight and testicular weight. Stress was produced by unpredictable deprivation of food on 30% of the days during the 6-week long photoperiod. We hypothesized that hypophysectomy attenuates stress tolerance, and thus prevent the growth of body weight and testicular weight compared to the sham-operated animals. The present findings clearly showed that the body weight gain was more suppressed in the hypophysectomized animals than that in the sham-operated ones. Our results also clearly indicated that the testicular weight/100g B.W. in the hypophysectomized animals was more suppressed than in the sham-operated ones and thus, the suppression ratio(SR) in the hypophysectomized animals was much higher than that in the sham-operated ones. The working hypothesis that stress tolerance will be attenuated by hypophysectomy was confirmed under long photoperiods from the present findings. Less
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