Depressed atrial inotropic response in the rat with chronic ethanol ingestion

Consumption of ethanol for long periods of time has been correlated with cardiac dysfunction as well as changes in function of the autonomic nervous system. This study looked at the effect of chronic ethanol ingestion on atrial contractility and atrial muscarinic and beta adrenoreceptors. Male Long-Evans hooded rats were pair-fed on ethanol (E) or normal (N) liquid diet for 40 weeks. The E diet supplied 35-39% of calories as ethanol. The atria from E rats had significantly lower baseline and peak contractility. They also showed a higher incidence of failure induced by isoproterenol. There was no difference in concentration or binding characteristics of beta-adrenoreceptors or muscarinic receptors. The data suggest that the negative inotropism caused by ethanol ingestion is the result of some mechanism other than changes in autonomic receptors.