Effect of ketamine on thermoregulation in rats

Abstract

Intraperitoneal administration of ketamine produced dose-dependent hypothermia at the ambient temperatures (T_a) of both 8 and 23 °C in unanesthetized rats. At a T_a of 8 °C, the hypothermia was brought about solely by a decrease in metabolic heat production. There were no changes in either the tail skin temperature (T_tail) or the sole skin temperature (T_sole). At a T_a of 23 °C, the hypothermia was due to an increase in T_tail, an increase in T_sole, and a decrease in metabolic heat production. However, at a T_a of 31 °C, there were no changes in rectal temperature in response to ketamine application, since neither heat production nor skin temperatures (e.g., T_tail and T_sole) was affected by ketamine at this T_a. The data indicate that the effect of the drug treatment may be to decrease heat production and (or) increase heat loss.