Alpha-adrenoceptor blockade prevents exercise-induced vasoconstriction of stenotic coronary arteries

Details

Serval ID
serval:BIB_DE0D7498964F
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Alpha-adrenoceptor blockade prevents exercise-induced vasoconstriction of stenotic coronary arteries
Journal
Journal of the American College of Cardiology
Author(s)
Julius  B. K., Vassalli  G., Mandinov  L., Hess  O. M.
ISSN
0735-1097 (Print)
Publication state
Published
Issued date
05/1999
Volume
33
Number
6
Pages
1499-505
Notes
Journal Article --- Old month value: May
Abstract
OBJECTIVES: The study aimed to evaluate the role of alpha-adrenergic mechanisms during dynamic exercise in both normal and stenotic coronary arteries. BACKGROUND: Paradoxical vasoconstriction of stenotic coronary arteries has been reported during dynamic exercise and may be due to several factors such as alpha-adrenergic drive, a decreased release of nitric oxide, platelet aggregation with release of serotonin, or a passive collapse of the vessel wall. METHODS: Twenty-six patients were studied at rest, during two levels of supine bicycle exercise and after 1.6 mg sublingual nitroglycerin. The alpha-blocker phentolamine was given to 16 patients before exercise, five of whom had also taken a beta-adrenergic-blocker the same morning. Ten patients served as controls. The cross-sectional areas of a normal and a stenotic coronary vessel were determined by biplane quantitative coronary arteriography. RESULTS: In the normal vessel segments, coronary cross-sectional area did not change after phentolamine injection, but increased in all patient groups similarly during exercise. Although coronary vasoconstriction existed in stenotic vessel segments in control patients, phentolamine-treated patients showed exercise-induced vasodilation without difference in patients with and without chronic beta-blockade. CONCLUSIONS: Exercise-induced vasoconstriction of stenotic coronary arteries is prevented by intracoronary administration of phentolamine. There was no difference in coronary vasomotion between patients receiving phentolamine alone and patients receiving phentolamine in addition to a beta-blocker. This finding suggests that exercise-induced vasoconstriction is mediated not only by endothelial dysfunction but also by alpha-adrenergic mechanisms.
Keywords
Adrenergic alpha-Antagonists/*administration & dosage/adverse effects Adrenergic beta-Antagonists/administration & dosage/adverse effects Adult Aged Atenolol/administration & dosage/adverse effects Coronary Angiography/drug effects Coronary Circulation/*drug effects/physiology Coronary Disease/*drug therapy/physiopathology Exercise Test/*drug effects Female Heart Catheterization Hemodynamic Processes/drug effects Humans Male Metoprolol/administration & dosage/adverse effects Middle Aged Nitroglycerin/administration & dosage/adverse effects Phentolamine/*administration & dosage/adverse effects Premedication Vasoconstriction/*drug effects/physiology Vasodilator Agents/administration & dosage/adverse effects
Pubmed
Web of science
Open Access
Yes
Create date
28/01/2008 10:32
Last modification date
20/08/2019 16:02
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