POSTERIOR HYPOTHALAMIC ACTIVITY AND CORTICAL CONTROL DURING THE PGE(1) HYPERTHERMIA

THE firing rate of the posterior hypothalamic neurones and interscapular brown adipose tissue and colonic temperatures (T-IBAT and T-C) were monitored in 36 urethane-anaesthetized male Sprague-Dawley rats before and after an intracerebroventricular (i.c.v.) injection of 400 ng prostaglandin E(1) (PGE(1)) or saline. The i.c.v. injection was preceded by functional decortication in half of each group. The results show an increase of firing rate, T-IBAT and T-C after PGE(1) injection in the rats without decortication. Functional decortication significantly reduced these enhancements. These findings demonstrate that the posterior hypothalamus plays a significant role in the hyperthermia induced by PGE(1) and that the cerebral cortex is involved in the control of posterior hypothalamic activity.