MOLECULAR ASPECTS OF REGULATION OF CARDIAC CONTRACTION

Contractility of the myocardium is determined by the interaction of co ntractile (actin and myosin) and regulatory (troponin and tropomyosin) proteins in the presence of calcium ions and chemical energy. The for mation of the actonmyosin cormplex is affected by the modulatory (C-, F-, M-proteins, actinins) and interstitial proteins (different types o f collagens, glycoproteins, glycosaminoglycans, elastins). Cardiac hyp oxia is accompanied by qualitative and quantitative changes in both co llagenous (change in the proportion of different extracellular matrix proteins! and non-collagenous proteins (formation of different isomyos ins and isoforms of actins or regulatory proteins). This remodelling o f cardiac musculature influences significantly the process of contract ion and relaxation in the hypoxic myocardium.