l-745870 and Hypothermia

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(1) 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.

Topics: Animals; Aporphines; Benzazepines; Benzopyrans; Body Temperature Regulation; Dopamine Agonists; Dopamine Antagonists; Hypothermia; Indoles; Oxazines; Piperazines; Piperidines; Pyridines; Pyrimidines; Pyrroles; Rats; Rats, Wistar; Receptors, Dopamine D1; Receptors, Dopamine D2; Receptors, Dopamine D3; Receptors, Dopamine D4