Fenfluramine-induced hyperthermia and stimulation in the rabbit.

Fenfluramine produces dose-related hyperthermia and behavioral stimulation in rabbits following intravenous administration. Both responses were antagonized by pretreatment with cinanserin, cyproheptadine, or fluxetine. Methergoline likewise abolished the stimulatory effect of fenfluramine and produced a partial blockade of the hyperthermia. Haloperidol was ineffective as a fenfluramine antagonist. This study demonstrates that fenfluramine-induced hyperthermia and stimulation in the rabbit result from an indirect action upon serotonergic receptors.