1988 Fiscal Year Final Research Report Summary
Investigation of the preventive mechanism against superheating during lever-pressing behavior in intracranial self-stimulating rats.
| Project/Area Number |
62570073
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
環境生理学(含体力医学･栄養生理学)
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| Research Institution | Osaka University |
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Principal Investigator |
TANAKA Hideto Osaka Univ., Med. Sch., Assistant, 医学部, 助手 (60163557)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Intracranial Self-Stimulating Rat / Brain-Reward System / 体温調節系 |
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| Research Abstract |
To investigate the preventive mechanism against body superheating, I examined autonomic and behavioral heat-loss responses during lever-pressing behavior in intracranial self-stimulating rats. The results were as follows; 1. Rats that continuously pressed a lever for 1 hour at an ambient temperature (Ta) of 22゜C interrupted lever-pressing and showed heat-loss behaviors, such as grooming and body extension, at a Ta of 36゜C. Hypothalamic temperature (thy) at the time of first body extension was higher than that after 1 hour of lever-pressing at a Ta of 22゜C. 2. In tail amputation experiment, thy at the onset of the body extension after tail amputation was higher than that after 1 hour of lever-pressing under control condition (pre-tail amputation). 3. The magnitude of the reward, as reflected in current intensity, affects both autonomic and behavioral heat-loss responses. At a Ta of 22゜C, tail vasodilation during the lever-pressing behavior began at higher Thy at higher current intensity. At a 36゜C, body extension began at higher Thy at higher current intensity. 4. When preoptic and anterior hypothalamus was warmed, lever-pressing behavior interrupted and heat-loss behaviors showed. The greater the intensity of stimulating current, the higher the warming threshold Thy for body extension begin. These results suggest that deep body temperature, especially hypothalamic temperature is important for the prevention against body superheating and brain-reward system affects thermoregulatory system.
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