Effects of gender on the cardiac toxicity elicited by chronic ethanol intake in rats.

Experiments were designed to determine if gender influences the cardiac toxicity elicited by chronic high-level ethanol intake. Male and female ethanol-preferring P-rats were allowed free access to drinking water or water containing 25% ethanol for 6 months. Left atrial preparations were then isolated, bathed in Krebs-Henseleit solution (37 degrees C), and used to examine basal contractility at 3.0 Hz stimulation, the force-frequency relationship, and the positive inotropic response to the beta-adrenoceptor agonist isoproterenol. Basal contractile function was not affected significantly by ethanol in either gender; however, atria from ethanol-treated male rats displayed diminished contractility compared to control males when measured at slow stimulation frequencies (0.1 and 0.2 Hz), during post rest potentiation (at rest intervals of 20-60 s), and in response to higher concentrations of isoproterenol (> or =3 x 10(-7) M; EC50 values were not affected). In contrast, female atria showed no effect of chronic ethanol consumption. These data suggest that ethanol consumption diminishes the cardiac reserve in male, but not female rats.