DIHYDREXIDINE PRODUCES HYPOTHERMIA IN RATS VIA ACTIVATION OF DOPAMINED-1 RECEPTORS

The selective dopamine D-1 receptor agonist dihydrexidine (2.0-8.0 mg/ kg, s.c.) caused a dose-dependent decrease in core temperature in rats . The hypothermia produced by dihydrexidine (4.0 mg/kg), was completel y blocked by the dopamine D-1 receptor antagonists SCH 23390 (0.1 mg/k g, s.c.) or NNC 687 (4.0 mg/kg, s.c.), but not by the dopamine D-2/3 r eceptor antagonist raclopride (0.2 mg/kg, s.c.). Neither of the dopami ne antagonists by themselves produced any effects on core temperature. The present results provide important evidence for the notion that ac tivation of dopamine D-1 receptors induces hypothermia in rats. (C) 19 97 Elsevier Science Ireland Ltd.