| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1987: ¥1,800,000 (Direct Cost: ¥1,800,000)
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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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