[Mathematical model of a generalized calcium buffer in cardiac muscle cells]

The problem of reduction of the earlier model for the calcium buffer system of cardiomyocytes was solved. A simpler model of generalized buffer, was obtained, which reproduces the behavior of the initial system in typical situations. To identify the parameters of the equations of the generalized buffer, recursive algorithms of filtration were developed. The model consists of two equations, which describe separately the fast and slow components of the buffer system. It is shown that the error of the generalized buffer model relative to the initial model of the calcium buffer system does not exceed 10% in a wide range of Ca2+ transients. The introduction of the generalized buffer into the model of mechanochemical coupling provides a more realistic description of a decrease in free calcium concentration. The new model adequately describes all mechanical events simulated by the initial model. In terms of the model, the effect of the slow component of the generalized buffer in a single contraction-relaxation cycle was studied. It was shown that the presence of the slow component leads to a marked decrease in the amplitude of contraction and increase in relaxation time.