Adult Binghamton Heterogeneous male mice received either nimodipine (5 mg/kg in saline) or vehicle 10 minutes prior to ethanol (1.02 g/kg) administration. Blood samples were obtained at 2, 10, 30, 60 and 120 minutes following the alcohol injection for determination of ethanol content. Although mean blood alcohol concentrations (BACs) were similar for both groups, nimodipine increased the variance in blood alcohol levels. Therefore, while nimodipine may alter alcohol pharmacokinetics through its interaction(s) with the genetic characteristics of the individual animal, the ability of this calcium slow channel blocking agent to enhance the psychotropic effects of alcohol cannot be due to altered absorption or elimination of the intoxicant.

Animals↗

PubMedDate not supplied

Cardiac inotropic effects of ethanol and calcium-channel modulators.

Our objective was to analyze the influence of ethanol ingestion on the in vitro inotropic effects of dihydropyridines alone, or in combination with ethanol, on atrial muscle from rats offered a liquid diet with ethanol ("ethanol rats," ER) or without ethanol ("normal rats," NR). Left atria from NR or ER were superfused with Tyrode's solution (36 degrees C) and driven at 1.5 Hz while recording tension. Bay K 8644 (BAYK) increased, while nimodipine or ethanol decreased, the tension developed and the velocity of development of tension. The preparations recovered rapidly from the effects of ethanol, but not from those of the dihydropyridines. The effects of ethanol and dihydropyridines in combination were the result of the additive or counteractive actions of the drugs. The effects of ethanol and nimodipine on ER preparations were not different from those observed in NR. The action of BAYK was significantly smaller in ER than in NR. In other words, chronic ingestion of ethanol reduced the positive inotropic effect of BAYK, but it did not modify the negative inotropic action of nimodipine or ethanol.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMedDate not supplied

Potentiation of the negative chronotropic action of verapamil by ethanol.

Ethanol and verapamil are both known to affect the transmembrane movement of Ca2+ in several biological systems. Both ethanol and verapamil have negative chronotropic actions on the isolated sinus node. The following study was designed to determine if these actions were synergistic. Studies on sinoatrial (SA) node-atrial preparations from rats pair-fed either sucrose or ethanol liquid diets showed that the preparations from the ethanol rats were more sensitive to verapamil. Studies on SA node-atrial preparations from control rats showed that acutely administered ethanol (20 mg/dl, 40 mg/dl) reduced spontaneous beating. In addition, verapamil had a greater negative chronotropic effect in the presence of ethanol (20 mg/dl, 40 mg/dl) than it did alone. It is hypothesized that the ethanol-verapamil interaction is mediated through a reduction in transmembrane Ca2+ movement.

Animals↗