A Computational Study on the Effect of Intracellular Calcium Concentration and ATP on Detrusor Smooth Muscle Contraction

The current study investigates the interplay between two important regulatory cellular signals that control contractions in the muscle, namely, intracellular calcium concentration and ATP. In this work, we have attempted to study how two regulatory signals interplay to affect the contractile responses of the muscle. The action of ATP hinders the myosin and actin from binding to each other, whereas, the effect of intracellular calcium mediates their cross-linkages. Thus, the study of two opposing signals and the effect of their interplay on the filament properties as well as on the contractile responses have been studied here. The Hai and Murphy contraction model has been modified to perform the current study. The ATP dependency was introduced into this model and through our simulations, we were able to demonstrate the importance of incorporating the same. Our model was able to reproduce physiologically realistic contraction profiles and stress values that befits a smooth muscle. Further, we used our model to estimate duty ratio and sliding velocity for the filament, under normal, loaded and pathological conditions.