Alterations in the endothelial G-protein coupled receptor pathway in epicardial arteries and subendocardial arterioles in compensated left ventricular hypertrophy.
The present study was designed to compare alterations of endothelium-dependent vasorelaxation in coronary epicardial arteries and subendocardial arterioles occurring in left ventricular hypertrophy (LVH) secondary to 60 days of aortic banding in a porcine model. Development of LVH was documented by echocardiogram and the endothelial function of subendocardial and epicardial vessels was studied by constructing concentration-response curves in a pressure myograph and standard organ chambers, respectively. 5-HT induced relaxations were reduced (p<0.05) in both vessel types isolated from pigs with LVH. Dilations of subendocardial arterioles and epicardial vessels to UK14304 were depressed by LVH. In the presence of Nomega-nitro-L-arginine (L-NNA), EDHF solely accounts for BK-induced relaxations; it fully compensates for the loss of NO in arterioles, but only partially in epicardial arteries isolated from LVH swine. Endothelium-independent relaxations induced by SNP were not altered in both vessel types from the LVH group. In a porcine model of LVH secondary to 60 days of aortic banding, the associated coronary endothelial dysfunction preferentially involves Gi-protein mediated relaxations in arterioles and arteries but also affects Gq-protein mediated relaxations in epicardial coronary arteries.
Aubin
Marie-Claude
MC
Research Center, Montreal Heart Institute and Université de Montréal, Montreal (QC), Canada.
Gendron
Marie-Eve
ME
Lebel
Vickie
V
Thorin
Eric
E
Tardif
Jean-Claude
JC
Carrier
Michel
M
Perrault
Louis P
LP
D000818:Animals; D001160:Arterioles / Q000378:metabolism / Q000473:pathology; D001685:Biological Factors / Q000378:metabolism; D003331:Coronary Vessels / Q000378:metabolism* / Q000473:pathology; D004452:Echocardiography; D004730:Endothelium, Vascular / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D017379:Hypertrophy, Left Ventricular / Q000378:metabolism* / Q000473:pathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013552:Swine; D014664:Vasodilation / Q000502:physiology
D001685:Biological Factors; C067410:endothelium-dependent hyperpolarization factor; D009569:Nitric Oxide; D019204:GTP-Binding Proteins