The effects of a decarboxylase inhibitor, benserazide, on both thermoregulation and chlorpromazine-induced hypothermia in rats.

Intraperitoneal administration of a peripheral decarboxylase inhibitor benserazide (Ro4-4602) to unanesthetized rats produced alterations in body temperature which depended on ambient temperature. In the cold, hypothermia was brought about by a decrease in metabolic heat production. At room temperature, a dose-dependent hypothermia was preceded by a slight hyperthermia. The hypothermia was due to an increase in skin temperature (tail) and a decrease in metabolic heat production, while the hyperthermia was due to a decrease in skin temperatures (both tail and footsole) and an increase in metabolic heat production. In the heat, hyperthermia responses to benserazide were associated with decrease in skin temperature (both tail and footsole). Benserazide treatment produced no significant change in brain 5-HT content. Chlorpromazine-induced hypothermia was greatly enhanced after pretreatment of the animals with benserazide at room temperature (22 degrees).