Platelet-free calcium and vascular calcium uptake in ethanol-induced hypertensive rats.

Abstract

This study examined the effect of moderate ethanol intake on systolic blood pressure, platelet cytosolic free calcium, aortic calcium, and rubidium-86 uptake in Wistar-Kyoto rats. Twelve Wistar-Kyoto rats, aged 6 weeks, were given 5% ethanol in drinking water the first week followed by 10% ethanol in drinking water for the next 6 weeks. Twelve control animals were given regular tap water. Systolic blood pressure in the ethanol-treated rats was significantly higher (p<0.05) than that in controls after 1 week and remained higher throughout the study. At 13 weeks of age, platelet cytosolic free calcium and calcium uptake by aortas were significantly higher (p< 0.001) in ethanol-treated animals as compared with those in controls. Ethanol intake did not affect aortic ouabain-sensitive 6 -8 However, the mechanisms by which ethanol intake elevates blood pressure is not known.Abnormal contractile activity of the vascular smooth muscle is considered to be one cause for the development of hypertension.9 The contractile activity of vascular smooth muscle is regulated by the level of intracellular free calcium ions ([Ca 2+ ]j). "12 It has been suggested that factors leading to an increased [Ca 2+ ]i within the vascular smooth muscle cell may be responsible for the increased contraction of the smooth muscle and the development of hypertension. Such factors may be an increased entry of calcium ions through the cell membrane via calcium channels or an increased release of calcium ions within the smooth muscle cells. Calcium influx through cell surface calcium channels is a major contributing factor to cytosolic free calcium. 1314 In the present study, we investigated the effect of an oral intake of 10% ethanol in drinking water on systolic blood pressure, platelet cytosolic free calcium and aortic calcium, and ^Rb* uptake in Wistar-Kyoto rats. Methods Animals, Diet, and Administration of EthanolMale WKY rats from Charles River, Quebec, Canada were used in this study. All rats were given standard rat chow throughout the study and had free access to water or water/ethanol mixture. At 6 weeks of age, rats were divided into two groups: a control group (12 rats) and an ethanol group (12 rats). Animals in the control group were given regular drinking water from the tap, and the ethanol group was given 5% vol/vol ethanol in tap water in the first week and 10% ethanol in tap water from the second through the

Genetic differences in ethanol metabolizing enzymes and blood pressure in Japanese alcohol consumers

“…Namely, a significant association between facial flushing response and the presence of ALDH2*2 allele was observed in 53 individuals, and in a subsequent large-scale study on 1000 or more individuals, drinkers manifesting the flushing response showed a higher prevalence of hypertension than those who did not. Itoh et al 5 thus speculated that people who have ALDH2*2 allele are more sensitive to the pressor effect of alcohol, and referred to the pathogenetic role of acetaldehyde in BP elevation in drinkers, which is consistent with the hypothesis proposed by Vasdev et al [6][7][8][9] from the results of studies on rats fed ethanol-water solution.…”

“…The pathogenesis of alcohol-induced hypertension as related to acetaldehyde has been proposed by Vasdev et al from the findings in experiments on rats fed ethanol water solution, namely, parallel elevations in BP and cytosolic-free calcium concentration in the platelets, 6,7 and the prevention of those elevations by the administration of aldehyde absorbing substances. 8,9 Vasdev et al speculated that BP in drinkers is elevated due to increased vascular smooth muscle tonus owing to the higher intracellular calcium caused by the effect of acetaldehyde on the cell-membrane calcium exchange.…”

Physio-pathological effects of alcohol on the cardiovascular system: its role in hypertension and cardiovascular disease

“…In their study, the plasma level of norepinephrine was decreased in ethanol-fed animals. Vasdev et al 82 observed BP elevation after 1 week during the administration of ethanol (5-10%) to Wister Kyoto rats. They noted increases in the concentration of platelet intracellular calcium ions and the uptake of calcium in the aorta.…”

Antihypertensive and antioxidant effects of Allanblackia floribunda Oliv. (Clusiaceae) aqueous extract in alcohol- and sucrose-induced hypertensive rats

“…It was demonstrated that intracellular Ca 2+ in a vascular smooth muscle cell preparation, even in the presence of Ca 2+ channel blockade, increases with ethanol (Vasdev et al, 1991). Ethanol has complex direct vascular effects, which include basal vasoconstriction and prominent elastic lamellae fragmentation which affects vessels elasticity (Estruch and Coca, 2004).…”