The response of retinal vasculature to angiotensin.
A retinal arterial constriction was produced in anesthetized cats with a continuous transvitreal infusion of angiotensin I or angiotensin II (Ile-5). Constriction of vessels near the infusion cannula tip occurred over a range of angiotensin II concentrations from 10(-9) to 10(-4) molar, and was reversibly blocked by a ten-fold excess of the competitive antagonist saralasin. Constriction did not occur in response to angiotensin I if angiotensin-converting enzyme was blocked with Captopril. Control infusions of saline did not elicit a contraction of the retinal arteries. Severe axonal and inner retinal damage and necrosis occurred when angiotensin II produced a prolonged vasospasm, but not after infusion with control solutions, or when-constriction caused by angiotensin was brief.
D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002415:Cats; D005260:Female; D008297:Male; D009898:Optic Disk / Q000098:blood supply / Q000473:pathology; D012160:Retina / Q000187:drug effects / Q000473:pathology; D012161:Retinal Artery / Q000187:drug effects*; D012504:Saralasin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
D000804:Angiotensin II; D000803:Angiotensin I; D012504:Saralasin