Body-temperature regulation in the normal and cold-acclimatized cat

¹ Environmental Physiology Branch, Civil Aeromedical Research Institute, Federal Aviation Agency, Oklahoma City, Oklahoma

The role of the anterior hypothalamus as a temperature-sensible area serving a thermal regulatory input function for body-temperature control in cats living at 25 C (noncold acclimatized) or 5 C (cold acclimatized) was tested by selectively changing diencephalic temperatures in the unanesthetized animal resting at 23 C ambient temperature. Extremity and internal body-temperature and metabolic-rate responses were monitored during the induced thermal shifts. Both groups of animals showed greater peripheral vasomotor and internal body-temperature changes consequent to hypothalamic heating than cooling; no modification of these test patterns was noted as a function of whole-body cold acclimatization. The temperature-sensible anterior hypothalamic areas appear to be more influential in protecting against hyperthermia than hypothermia and their function in biothermal control does not appear to be altered by whole-body cold acclimatization.