[Mitochondrial contacts of cardiomyocytes].

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.