Does B-HT 920 Lower Intraocular Pressure in Cats by Interacting with α2- and/or DA2Adrenoceptors?

摘要

ABSTRACTTopical administration of B-HT 920 (50 μg) to the eyes of normal unanesthetized cats produced decreases in intraocular pressure and pupil diameter. The ocular hypotensive effect of B-HT 920 was eliminated by sympathectomy and pretreatment with sulpiride (2 mg/kg, s.c.). B-HT 920 also produced dose-related inhibition of contractions of the cat nictitans elicited by stimulating the pre- and postganglionic sympathetic trunks. B-HT 920-induced suppression of the contracting nictitans was antagonized more effectively by relatively selective DA2antagonists, sulpiride and domperidone, than by rauwolscine, a relatively selective α2-adrenoceptor antagonist. These data suggest that B-HT 920 produces ocular hypotension in the cat by interacting predominantly with DA2receptor on peripheral sympathetic nerve