[Effect of conorphone on the dimensions of the myocardial infarct and the ultrastructural changes in the adjacent tissue].

Among contemporary problems of cardiovascular therapy, pain management in the cardiac patient is an important issue. Correct selection of a suitable analgesic drug is important in the acute phase of myocardial infarction because pain relief prevents adrenergic response which aggravates unbalance between myocardial oxygen supply and demands. Until today morphine has been the best choice, nevertheless its side effects and limited availability demands pharmacological alternatives. Meperidine has been used for this purpose although its anticholinergic and narcotic profiles do not fulfill the therapeutic requirements. Conorphone is a codeine derivative which retains analgesic potency without other narcotic side effects and which presents an antagonistic profile for the remainder of opiate effects. Preliminary studies demonstrate that conorphone lacks cardiovascular side effects. Conorphone also shows antiarrhythmic effects in experimental models such as in rat in which arrhythmias were induced by coronary ligation. In this paper a morphologic analysis with electron microscopy was done on adjacent myocardial tissue next to an area of infarct. Experimental myocardial infarction was induced by ligation of descendant branch of left coronary artery, four hours prior to rat sacrifice and suitable samples for ultrastructure study were obtained. The experiments demonstrate that a group of rats that received 3.1 mg/kg of conorphone had less expressions of cellular damage when compared with similar myocardial areas of a control group of rats.