The effects of bombesin injected into the anterior and posterior hypothalamus on body temperature and oxygen consumption

Bombesin was microinjected into the lateral ventricle, preoptic area, and posterior hypothalamus of cold-exposed rats. Preoptic and ventricular injections produced dose-dependent depressions in metabolism with subsequent hypothermia. Furthermore, injections into the preoptic area elicited greater depressions in body temperature than equivalent doses injected into the lateral ventricle. No changes in oxygen consumption or body temperature resulted from posterior hypothalamic administration of the peptide. The data suggest that the preoptic area may be an important site of action for bombesin and that bombesin-induced hypothermia is mediated, at least in part, by a reduction in metabolic rate.