Chronic haloperidol treatment potentiates apomorphine- and ethanol-induced hypothermia in the rat

Supersensitivity developed in the central dopaminergic system of the rat after 21 days of chronic haloperidol injection. This was indicated by a higher level of apomorphine-elicited stereotypic behavior and by higher concentrations of striatal 3H-spiroperidol binding sites in haloperidol-treated rats compared to saline-treated controls. The chronic haloperidol treatment did not affect the baseline body temperature but potentiated both apomorphine- and ethanol-induced falls in core temperature. Such potentiation may also be related to dopamine supersensitivity. However, no significant correlation was found between apomorphine- or ethanol-induced hypothermia and apomorphine-elicited stereotypic behavior or the concentration of striatal 3H-spiroperidol binding sites. Hence, the nigrostriatal dopamine system does not appear to be involved in the development of hypothermic responses to these agents.