Abstract
The temperature responses of the pigeon to serotonin, reserpine, chlorpromazine and LSD-25 were investigated. It was demonstrated that a rapid hypothermia and depression follow the administration of all compounds except chlorpromazine. Serotonin, reserpine and chlorpromazine were shown to have certain prophylactic and therapeutic value on the LSD-25-induced hypothermia. The data indicate that a mutual antagonism exists in the interaction of these compounds. It is suggested that the mechanism of action of these drugs is quite complex, leading to mixed reactions, depending perhaps on what measurement is being considered.