Simulating niflumic acid effect on sinoatrial node cells

It was recently reported that niflumic acid was capable of inhibiting the hyperpolarization-activated pacemaker current. To obtain insights into the ionic mechanisms governing niclumic acid effect on cardiac sinoatrial (SA) myocytes, computer simulations were performed based on a computer model of electrical activity of SA node cells. One cell was described by 15 nonlinear first-order differential equations that describe the time course of transmembrane potential difference, ionic concentrations, and states of the voltage gated ionic channels. The inhibition of the hyperpolarization-activated pacemaker current contributed to the chronotropic effect by reducing the rate of diastolic depolarization.