The effect of chronic ethanol ingestion on the inotropic effect of nifedipine.

The effect of chronic ethanol ingestion on the positive and negative inotropic effects of nifedipine were tested using isolated rat left atria in a force transducing system. There was a significant relative and absolute decrease in the positive inotropic effect of nifedipine in tissues from rats ingesting ethanol (E) as compared to tissue from non-ethanol ingesting rats (N) at low nifedipine concentrations. This change may be mediated by a change in efficiency of the contractile apparatus or membrane fluidity.