Evidence for regulation of body temperature in rats by dopamine D2 receptor and possible influence of D1 but not D3 and D4 receptors

The dopamine D-3 receptor agonist PD 128907 decreased body temperature in the rat. The selective dopamine D-3 and D-4 receptor antagonists, A-437203 and L-745,870, respectively, did not prevent this effect. In contrast, PD 128907-induced hypothermia was antagonized by SCH 23390, a selective D, receptor antagonist, and by L-741,626, a selective D-2 receptor antagonist. Moreover, the selective D-2 receptor agonist trihydroxy-N-n-propylnoraporphine (TNPA) elicited a robust hypothermia which was prevented by pretreatment with L-741,626 but not by A-437203. In agreement with previous data obtained in D-3 knock-out mice, present results suggest that D-2 rather than D-3 receptors mediate dopamine receptor agonist-induced hypothermia in rats. In addition, it appears that both D-1 and D-2 receptors may be involved in a cooperative manner. (C) 2003 Elsevier Science Ltd. All rights reserved.