Alcohol induces relaxation of rat thoracic aorta and mesenteric arterial bed.
OBJECTIVE
The aim of this study was to investigate the effect of alcohol on rat artery and its underlying mechanism.


METHODS
The tension of isolated Sprague-Dawley rat thoracic aortic rings and the pressure of rat mesenteric arterial beds perfused with different concentrations of alcohol (0.1-7.0 per thousand) were measured.


RESULTS
At resting tensions, alcohol caused a concentration-dependent relaxation on endothelium-denuded aortic rings precontracted with KCl (6 x 10(-2) mol/L) or phenylephrine (PE, 10(-6) mol/L), and this effect was most evident on rings at a resting tension of 3 g. Alcohol induced much less vasodilation on endothelium-intact rings. Alcohol inhibited the CaCl(2)-induced contraction of endothelium-denuded aortic rings precontracted with KCl or PE. Incubation of rings with dantrolene (5 x 10(-5) mol/L), a ryanodine receptor blocker, or 2-aminoethyl diphenylborinate (7.5 x 10(-5) mol/L), an IP(3) receptor blocker, attenuated the vasodilating effect of alcohol on rings precontracted with PE. Alcohol also concentration-dependently relaxed rat mesenteric arterial beds precontracted with KCl (6 x 10(-2) mol/L) or PE (10(-5) mol/L), which was more potent on endothelium-denuded than on endothelium-intact beds.


CONCLUSIONS
Alcohol has a vasodilating effect on rat artery depending on the resting tension. Both extracellular and intracellular Ca(2+) mobilization of vascular smooth muscle cells are involved in the vascular effect of alcohol.
Ru
Xiao-Chen
XC
Department of Physiology, Zhejiang University School of Medicine, 388 Yuhangtang Road, Hangzhou 310058, China. xiaqiang@zju.edu.cn
Qian
Ling-Bo
LB
Gao
Qin
Q
Li
Yan-Fang
YF
Bruce
Iain C
IC
Xia
Qiang
Q
D000704:Analysis of Variance; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D001158:Arteries / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D008643:Mesentery / Q000098:blood supply* / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects*
D000431:Ethanol