ETa-receptor blockade, but not ACE inhibition, blunts retinal vessel response during isometric exercise
| العنوان: | ETa-receptor blockade, but not ACE inhibition, blunts retinal vessel response during isometric exercise |
|---|---|
| المؤلفون: | Barbara Wimpissinger, Kaija Polak, Kerstin Jandrasits, Alexandra Luksch, Leopold Schmetterer |
| المصدر: | American Journal of Physiology-Heart and Circulatory Physiology. 290:H1693-H1698 |
| بيانات النشر: | American Physiological Society, 2006. |
| سنة النشر: | 2006 |
| مصطلحات موضوعية: | Adult, Male, medicine.medical_specialty, Endothelin A Receptor Antagonists, Physiology, Physical Exertion, Angiotensin-Converting Enzyme Inhibitors, Isometric exercise, Peptides, Cyclic, Double-Blind Method, Enalapril, Isometric Contraction, Physiology (medical), Internal medicine, Renin–angiotensin system, medicine, Humans, Cross-Over Studies, Endothelin-1, business.industry, Angiotensin II, Retinal Vessels, Placebo Effect, Receptor, Endothelin A, Endothelin 1, Blockade, Endocrinology, Vasoconstriction, Exercise Test, Female, medicine.symptom, Cardiology and Cardiovascular Medicine, business, medicine.drug |
| الوصف: | Angiotensin II and endothelin-1 are potent vasoconstrictors that appear to play a role in retinal blood flow regulation. In the present study, we investigated the possible role of the angiotensin and the endothelin system in the regulation of retinal vessel diameters during isometric exercise in healthy humans. The study design was randomized, double-masked, placebo-controlled, and three-way cross over. Twelve healthy subjects performed squatting exercises for 6 min during infusion of either an angiotensin-converting enzyme inhibitor (enalapril), an ETA-receptor antagonist (BQ-123), or placebo. Retinal vessel diameters were measured continuously with the Zeiss retinal vessel analyzer. Systemic hemodynamics were assessed noninvasively, and intraocular pressure was measured with applanation tonometry. Squatting induced a significant increase in blood pressure and pulse rate, which was paralleled by a vasoconstriction in retinal arteries and veins. Intraocular pressure was only slightly increased during the squatting periods. BQ-123 significantly blunted the exercise-induced decrease in venous ( P < 0.01) and arterial ( P < 0.02, ANOVA) vessel diameters but had no effect on basal retinal diameters. By contrast, enalapril did neither influence vessel diameter at baseline conditions nor in response to isometric exercise. The data of the present study indicate that retinal vasoconstriction during isometric exercise is modified by ETA-receptor blockade, whereas it is not altered by angiotensin-converting enzyme inhibition. Hence, the present data indicate that endothelin-1, but not angiotensin II, is involved in retinal blood flow regulation during isometric exercise. |
| تدمد: | 1522-1539 0363-6135 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::70e1b8ffbbe910f79f1f5effeccfb812Test https://doi.org/10.1152/ajpheart.00947.2005Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....70e1b8ffbbe910f79f1f5effeccfb812 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15221539 03636135 |
|---|