Ethanol induced hypertension in rats: reversibility and role of intracellular cytosolic calcium.

This study examined the reversibility of chronic ethanol induced increase in systolic blood pressure, elevated platelet cytosolic free calcium and aortic calcium uptake in rats and the effect of a calcium channel blocker on these changes. Twenty-four male Wistar-Kyoto rats, age 7 weeks, were divided into 4 groups of 6 animals each. Animals in group I were given water and group II, III and IV, 5% ethanol in drinking water for the next 7 weeks. Systolic blood pressure in the ethanol treated rats was significantly higher (p < 0.01) than in controls after 1 week and remained higher. After 7 weeks, group I was continued on water, group II on ethanol, group III was continued on ethanol but with the addition of verapamil 5 mg/100 ml in their drinking water and group IV was returned to normal drinking water for the next 7 weeks. After 14 weeks, systolic blood pressure, platelet cytosolic free calcium and aortic calcium uptake was significantly higher (p < 0.01) in rats given ethanol for 14 weeks and also in rats given ethanol for 7 weeks followed by water for 7 weeks as compared to controls. These two groups also showed smooth muscle cell hyperplasia with some thickening of the wall and narrowing of the lumen in small arteries and arterioles of kidney. Verapamil given to the ethanol treated rats normalized their blood pressure, platelet cytosolic free calcium, aortic calcium uptake and attenuated renal vascular changes. Discontinuation of ethanol treatment for 7 weeks did not reverse the hypertension or the adverse renal vascular changes in ethanol induced hypertensive rats.