Effect of nisoldipine on de-endothelialized large coronary artery in isolated working rabbit hearts

The effect of nisoldipine on coronary vascular resistances, cardiac performance and myocardial oxygen consumption was determined. Rabbit hearts were perfused with a perfluorochemical (FC-43) emulsion. Endothelium was removed from the obtuse marginal and the upper portion of the anterior descending coronary artery. Changes in the internal diameter of these arteries were visualized using injection of Patent Blue Dye (color arteriography). Mean internal diameter of coronary arteries and surface area/unit length were computer calculated. Nisoldipine reduced the constriction of coronary arteries and the decrease on coronary flow induced by histamine. Nisoldipine abolished or reduced the decrease in cardiac output, LVESP, dP/dt and myocardial oxygen consumption. The results demonstrate that in the supported rabbit heart preparation, nisoldipine is an effective dilator of large subepicardial coronary arteries, deprived of endothelial lining, and counteracts constriction of coronary resistance vessels. As a consequence nisoldipine improves performance of the ischemic myocardium.