Differential vascular actions of ethanol in feline middle cerebral and mesenteric artery

The vascular actions of ethanol on feline middle cerebral and mesenteric arteries were investigated in vitro. Ethanol (20-500 mM) caused potent contraction in cerebral arteries, but it contracted the mesenteric arteries only weakly. In the middle cerebral artery (but not in the mesenteric artery) ethanol (300 mM) potentiated the noradrenaline (5.10(-6) M) induced contractions. Antiserum for endothelin (in an appropriate concentration to inhibit endothelin-induced contraction; 0.02 mg/ml) did not inhibit the ethanol-induced contractions. Endothelium-dependent relaxations induced by acetylcholine and ATP were also affected by ethanol (300 mM); in the cerebral artery acetylcholine- but not ATP-induced relaxations, whereas in the mesenteric artery ATP- but not acetylcholine-induced relaxations were inhibited significantly. The results suggest that ethanol causes strong (endothelin-independent) contraction and facilitates the response to noradrenaline in the middle cerebral, but not in the mesenteric artery; and it selectively inhibits endothelium-dependent relaxation. These actions of ethanol may contribute to the development of vascular diseases.