Effect of Nisoldipine on De-Endothelialized Large Coronary Artery in Isolated Working Rabbit Hearts

Abstract

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.

Effect of Nisoldipine on Large Coronary Arteries in situ: Inhibition of Vasoconstriction Induced by Vasopressin

“…Our findings are in agreement with pre vious studies on coronary arteries in isolated perfused working rabbit heart preparations [ 13]; here, too, nisoldipine counteracts hista mine-induced vasoconstriction of large coro nary arteries and reduces large artery and total coronary vascular resistances. In the isolated rat heart, nisoldipine initiates dosedependent coronary vasodilation [33].…”

“…In summary, the results of our experi ments in situ support our recent study on the isolated supported working rabbit heart preparation [ 13]; the data confirm that nisoldipine has direct vasodilatory effect on the large coronary arteries in situ and effectively inhibits vasopressin-induced coronary vaso constriction.…”

“…We recently demonstrated in the isolated work ing heart preparation that nisoldipine re duced the constriction of large epicardial coronary arteries deprived of endothelium and diminished the decrease in coronary' flow induced by histamine [13]. The current experiments were undertaken to investigate the effect of nisoldipine on epicardial coro nary arteries of the rabbit heart in situ.…”