Effects on temperature of amines injected into the cerebral ventricles. A new concept of temperature regulation

The present experiments deal with a new central action of adrenaline, noradrenaline and 5-hydroxytryptamine (5-HT). They show that these amines affect body temperature when injected into the cerebral ventricles of an unanaesthetized cat. 5-Hydroxytryptamine raises the body temperature, whereas adrenaline and noradrenaline have the opposite effect and lower it, partiwlarly when it is elevated by either 5-HT or pyrogens similarly applied. These findings suggest that the three amines which are present in relatively high concentrations in the hypothalamus (Vogt, 1954; Amin, Crawford & Gaddum, 1954) play a role in the hypothalamic regulation of body temperature. The experiments are the outcome of two independent observations, the first of which is concerned with pyrogens and the second with the amines 5-HT, adrenaline, and noradrenaline. Pyrogens injected into the cerebral ventricles of a cat cause long-lasting fever and shivering. When the amines are similarly injected 5-HT produces shivering, whereas adrenaline and noradrenaline abolish drug-induced shivering. Petersdorf & Bennett (1959) produced fever by the injection of pyrogens into the cisterna magna of rabbits. Fever produced in cats by the injection of pyrogens into the cerebral ventricles through an indwelling cannula has been described by Sheth & Borison (1960) as well as by Villablanca & Myers (1963), who in addition noted that shivering occurred. The effects, which were obtained with doses of pyrogen too small to be effective on intravenous injection, occurred after a latency of about 1 hr, and the body temperature remained elevated for many hours. According to Villablanca & Myers, the pyrogens act on the anterior hypothalamus reached from the third ventricle, because when they injected the pyrogens directly into this region fever and shivering occurred. On the other hand, the effect did not