Predictions for epicardial ventricular action potentials of healthy and diabetic rats

A computer model of the epicardial ventricular cell has been developed from both voltage clamp and action potential data to determine the contribution of the outward K⁺ currents to the action potential variation in healthy and diabetic male rats. The epicardial ventricular cell model has two major components: a membrane model and a fluid compartment model. The membrane was represented by the membrane capacitance, the ionic currents, and the membrane pumps and exchanger. The ionic changes of Na⁺, Ca²⁺ and K⁺ were described for the lumped fluid compartment. Mathematical equations were developed to model the electrical changes observed in the two prominent K⁺ channels (the transient outward K⁺ current I_t, and the sustained outward K⁺ current I _sus) for the epicardial ventricular cells of the normal and streptozotocin-induced diabetic rats. The results conclude that the ventricular cell model can predict epicardial action potentials for the diabetic rats by decreasing the normal density of I_t by 45% and of I_sus by 40%