[Comparative study using colloidal lanthanum of defects in cardiomyocyte membrane permeability in deep ischemia and in isoproterenol exposure].

A comparative study of defects in permeability of contractile heart cell membranes in "calcium" necroses of the myocardium and "calcium-free" necroses developing in a focus of deep ischemia in experimental myocardial infarction was carried out. "Calcium" necroses of the myocardium were reproduced by inoculation of the experimental animals with toxic doses of isoproterenol. The time course of formation of permeability defects in the membranes correlated with the process of intracellular structural damage formation. Irrespective of the nature of the damaging factor, permeability of sarcolemma was found to be disturbed earlier than the appearance of defects in membranes of inner organelles. Various combinations of the toxic effect of excess calcium and oxygen deficiency determine specific features of morphogenesis of ultrastructural alterations in cardiomyocytes.