Suppressive effect of the dopamine D2 receptor agonist B-HT 920 on rat grooming.

The effect of the D2 agonist B-HT 920 was examined on three behavioural models of induced grooming in the rat. B-HT 920 potently inhibited the grooming elicited by a novel environment, whereas it stimulated the stretching-yawning syndrome. Pretreatment with the selective dopamine D2 receptor antagonist, sulpiride, reversed the phenomenon. When B-HT 920 was administered to rats before water immersion, it similarly antagonized total grooming; wet-dog shakes, detected in these same animals, were potently inhibited. Finally, B-HT 920 displayed inhibitory activity towards adrenocorticotropin hormone-induced excessive grooming. On the basis of these effects, the role of D2 receptor subtypes in the modulation of grooming is discussed.