Abstract
The heart is a mechanically functioning organ which consists of cardiomyocytes. Although it has been revealed that mechano-electric coupling plays an important role in cardiac physiology, it is difficult to investigate direct link between subcellular mechano-sensitive responses and tissue or organ functions in wet experiments. To integrate experimentally obtained findings in micro and macro study, we have developed a mathematical cardiac myocyte model based on Iribe-Kohl-Noble model. To describe mechano-sensitive properties, we implemented stretch activated channels (SACs), viscoelastic property of cytoskeleton or cytosolic structures, and shortening-rate dependency in troponin I (TnI) inactivation. Viscoelastic property in our model gave stretch-rate dependency in SACs activation, which reasonably reproduced mechanically induced ectopic beat after quick stretch and delayed increase in developed force after slow stretch. Shortening-rate dependent TnI inactivation reproduced afterload dependency in muscle mechanics previously reported. Our modeling study suggests advantages of computational biology in macro-micro integration in cardiac physiology.
