Effect of prazosin on aqueous humor dynamics in rabbits.
Prazosin hydrochloride, a systemic antihypertensive agent, lowers intraocular pressure when applied topically to normal rabbit eyes. A 0.01% solution of topically administered prazosin did not alter out-flow facility, episcleral venous pressure, systemic blood pressure, or ocular blood flow. Tonography suggested a 27% decrease in the rate of aqueous humor formation two hours following topical administration. Posterior chamber aqueous ascorbate levels were increased following topical administration of prazosin, which also suggested a decreased entry rate of water into the eye. The effect of prazosin on IOP was prevented by systemic pretreatment with phentolamine mesylate, an alpha-adrenergic blocking agent, but not by propranolol hydrochloride or atropine sulfate. This was consistent with the known action of prazosin as a postsynaptic alpha-adrenergic blocking agent.
D000287:Administration, Topical; D000818:Animals; D001082:Aqueous Humor / Q000032:analysis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D011817:Rabbits; D014822:Vitreous Body / Q000032:analysis
D011799:Quinazolines; D001205:Ascorbic Acid; D011224:Prazosin; D010646:Phentolamine