Influence of local temperature changes in the preoptic area and rostral hypothalamus on the regulation of food and water intake.

Abstract

AbstractLocal cooling of the preoptic area and rostral hypothalamus induced eating in the fed goat. After dehydration to the state of aphagia, cooling of this area inhibited the animal's urge to drink and induced eating. Although in a normal goat feeding practically stops when the rectal temperature exceeds 40° C (Appleman and Delouche 1958), local cooling of the preoptic area and the rostral hypothalamus induced the goat to eat hay at body temperatures above 41° C. Warming the same area inhibited eating in the hungry animal and induced the goat to drink large quantities of water.After inactivation of the preoptic“heat loss centre” by proton irradiation in a goat, the animal became adipsic but continued to eat hay with a seemingly good appetite at body temperatures above 41°C. The anorexic effect of warming the preoptic area thus does not seem to be due to a direct thermal effect on the hypothalamic“appetite centre”. The results provide direct evidence in favour of Brobeck‘s (1948)“thermostatic” theory of the regulation of food intake and justify the further extension of this theory to involve also the regulation of water intake.