Influencing of calcium paradox by membrane stabilizing agents: the role of sarcolemma and intercalated disc.

The purpose of this study was to focus on the role of the sarcolemma and intercalated disc in the induction and prevention of calcium paradox. Perfusion of the heart with Ca deficient solution produces only minor cytoplasmic ultrastructural changes. More obvious changes are seen in the sarcolemma. The cell surface shows a separation between the layers of the glycocalyx and the cells separate at the fascia adherens. These alterations resulted in the enhanced sarcolemmal membrane permeability, alteration and weakening of intercalated discs junctions. This was accompanied by intracellular accumulation of lanthanum. The application of membrane stabilizing agents, when the normal ultrastructure of the sarcolemma and intercalated disc is maintained, may prevent or at least attenuate the magnitude of deleterious effect of the calcium paradox on the heart. It is concluded that cell membrane significantly participates in the pathogenesis of the Ca paradox damage in the heart.