Thyrotropin-releasing hormone (TRH)-induced hyperthermia and behavioral excitation in rabbits

The intraventricular administration of thyrotropin-releasing hormone (TRH) to conscious rabbits produces a dose-related increase in body temperature, a compulsive scratching syndrome, and behavioral excitation. These effects are not antagonized by most adrenergic or serotonergic blockers, amine depletors, or most depressants. Given to rabbits pretreated with anesthetic doses of barbiturates or high doses of other sedatives or neuroleptics, TRH exerts an analeptic effect. The duration of pentobarbital anesthesia is markedly shortened. Of all the depressants tested, only morphine was resistant to the analeptic effect of TRH, although the morphine-induced hypothermia was reversed.