Temperature set-point changes induced by DA D2/3 and 5-HT1A receptor agonists in the rat.

The DA D2/3 receptor agonist 7-OH-DPAT (2 micromol kg(-1)) and the 5HT1A receptor agonist 8-OH-DPAT (0.6 micromol kg(-1)) both produced a marked and similar decrease in core temperature of 3-4 degrees C at 10 and 20 degrees C ambient temperature. At 30 degrees C there were no, or weak, effects. The decrease in core temperature was accompanied by a sudden increase in tail temperature, followed by a decrease as core temperature returned to basal values. The results suggest that the hypothermia produced by the respective DA D2/3 and the 5-HT1A receptor agonists 7-OH-DPAT and 8-OH-DPAT is an active process, in all probability due to changes in a hypothalamic set-point for temperature regulation.