ABSTRACT
Coronary arterial occlusion, maintained for 7 days in rabbits was accompanied by a marked and fairly stable drop in macroergic phosphates (ATP, creatine phosphate), seen in the perinecrotic and distant left and right ventricular myocardium. The administration of 0.5 mg/kg propranolol twice daily within 30-40 min after coronary arterial ligation resulted in a significant increase in ATP and the adenine nucleotides pool at a distance from the necrotic focus in the right and left ventricular myocardium on treatment days 3 and 7 and did not affect the recovery of normal creatine phosphate in the same myocardial areas. Propranolol treatment limited progressive death of myocardial cell population, reducing by 37% myocardial infarction size by day 7 of the experimental study, as compared to the situation in the untreated animals.
Subject(s)
Coronary Disease/drug therapy , Myocardium/metabolism , Phosphates/metabolism , Propranolol/therapeutic use , Acute Disease , Animals , Coronary Disease/metabolism , Coronary Disease/pathology , Drug Evaluation, Preclinical , Energy Metabolism/drug effects , Male , Myocardial Infarction/drug therapy , Myocardial Infarction/metabolism , Myocardial Infarction/pathology , Myocardium/pathology , Necrosis , Rabbits , Time FactorsABSTRACT
The myocardium of the left and right ventricles in mature rabbits has been studied electron microscopically. The material is fixed by means of vital perfusion and/or by immersion in 2.5% glutaraldehyde with cacodylate buffer 0.05-0.1 M, pH 7.4 and treated in 1% OsO4 with the same buffer. For revealing intercellular contacts and inter-mitochondrial gaps, colloid lanthanum is applied. In order the colloid particles penetrate into cytoplasm, the model of ischemic myocardium is used. The myocardial infarction is produced by ligation of the coronary artery. The inter-mitochondrial interactions in cardiomyocytes are various and can be performed not only via hyaloplasm, but immediately by means of direct specific inter-mitochondrial contacts (IC). The IC are limited areas of maximal bringing together of the external membranes of the adjoining mitochondria. These areas are characterized by an increase electron density both of the contacting mitochondrial membranes and of the contents in the intermembranous spaces. A close topographic connection is revealed between mitochondria and cytolemma in the zone of the gap intercellular junction of the intercalated disc, where the mitochondrial nexus complex is formed. The IC can evidently ensure the metabolic and adhesive connection between separate mitochondria.
