[Ultrastructural and functional changes in the myocardium and coronary vessels after massive blood loss].

The ultrastructure of cardiomyocytes and circulatory bed has been compared to transmembrane cAMP-dependent Ca2+ transport in experiments on the hearts of 14 dogs immediately after massive blood loss. The results an hour after non-compensatory hemorrhage have shown extra- and intracellular myocardial edema, central destruction of sarcomers, steep increase in the volume of agranular sarcomplasmic reticulum and T-system, different degree of damage of other organoids, and also disturbances in the ultrastructure of venous capillary and postcapillary section. The biochemical techniques used have shown a decrease in Ca2+ transporting ability of sarcolemma due to its AMP-dependent regulation of cardiomyocytes. Excessive Ca2+ storage in cytosole promoted the appearance of "constriction bands" in myofibrils.