Effect of ethanol on cardiac beta-adrenoceptors

Liquid diets are commonly used as vehicles for chronic administration of ethanol to rodents. After mice had consumed an ethanol-free liquid diet for either seven or eight days, the number of cardiac beta-adrenoceptors and the maximum response of adenylate cyclase to isoproterenol were decreased. This change was associated with a decrease in the number of high-affinity agonist binding sites. When mice were fed ethanol in the liquid diet, there was a further decrease in the number of cardiac low-affinity agonist (isoproterenol) binding sites, but no further change in the biochemical response to isoproterenol. The data suggest that stress and/or nutritional factors can alter the number, the coupling and the function of cardiac beta-adrenoceptors and that chronic ethanol ingestion enhances certain aspects of these changes.