Effect of Ethanol on the Regulation of Smooth Muscle Tone in Rat Aorta

Background and Objectives:The aim of this study was to determine the effect of ethanol on the regulation of vascular tone. Material and Methods:Using the rat aorta ring, the isometric contraction and 45Ca uptake were measured. Phorbol 12,13-dibutyrate (PDBu, phenylephrine, KCl were used for the regulation of smooth muscle tone. Results:Ethanol induced transient contraction in the rat aorta ring by in a dose-dependent manner. Ethanol suppressed the dose dependent contractile responses of the vascular strip by to phenylephrine, KCl and PDBu. Endothelium-dependent relaxation by due to acetylcholine was inhibited by ethanol. Ethanol depressed the 45Ca uptake by high KCl but not by phenylephrine or PDBu in the rat aorta. n-butanol selectively suppressed tonic contraction by high KCl, but t-butanol did do so not at the same concentration of as butanol in the rat aorta. PDBu-induced contraction was selectively suppressed by n-butanol but not by t- butanol. Conclusions:These findings suggest that the action effect of ethanol on phospholipase D is involved in the decreased response of the rat aorta strip by to vasoconstrictors. ( ( ( (Korean Circulation J 2001;31( ( ((2 :230-237