New Mathematical Models for the Mouse Atrial Fast Sodium Channel

The fast sodium channel (FSC) is one of the most important channels in the cardiomyocytes. It leads the activation of the cardiac action potentials and its dysfunction may leads to many severe pathologies. However, the currently widely used FSC model is not developed for mouse, and relatively outdated compared with the emerging experimental data on mouse atria, making the model less reliable in investigating the mechanisms underlying atrial arrhythmias. In this work, we intend to develop a new model for the mouse atrial FSC which can reproduce the newly published experimental data. The kinetics of and the current generated by our new model were thoroughly validated. We investigated the response of the new model to infra- or supra-threshold stimuli and found that it needs a smaller stimulus to be activated and has a higher driving ability compared with the old model. The current amplitude of the new model also shows a smoother stimulus-dependent curve than the old model. This model will be a more suitable tool in the research of atrial arrhythmias.