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Abstract #6404 Published in IGR 3-2
Effects of atropine and propranolol on retinal vessel diameters during isometric exercise
Jandrasits K; Polak K; Luksch A; Stark B; Dorner GT; Eichler HG; Schmetterer LOphthalmic Research 2001; 33: 185-190
PURPOSE: There is controversy regarding the nervous control of retinal blood vessels in humans. Most in vitro studies indicate that the intraocular part of the central retinal artery lacks autonomic innervation. The authors investigated the response of retinal vessels to isometric exercise during blockade of β-receptors (propranolol) or muscarinic receptors (atropine). METHODS: Twelve healthy subjects squatted for six minutes during infusion of either propranolol, atropine, or placebo. Blood pressure and pulse rate were measured noninvasively. Retinal vessel diameters were measured continuously using the Zeiss retinal vessel analyzer. RESULTS: Squatting induced a significant increase in blood pressure and pulse rate, which was paralleled by a decrease in retinal vein and artery diameters. Atropine did not change the retinal vessel response to isometric exercise. Propranolol significantly blunted the exercise-induced vasoconstriction in retinal arteries. CONCLUSION: This result likely indicates propranolol-evoked vasoconstriction in the extraocular parts of the central retinal artery during isometric exercise.
Dr K. Jandrasits, Department of Clinical Pharmacology, University of Vienna, Vienna, Austria
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)