[Formation of ectopic excitation in the heart under the action of aconitine. II. The generation of oscillatory fluctuations of the membrane potential and current].

The method of potential fixation was used to study the mechanism of the origin of membrane potential oscillations induced by aconitine (50, 100 mg/l) on isolated trabeculae of Rana ridibunda atrium. Some of the sodium channels change their properties under the effect of aconitine: these channels are activated at potentials close to the rest potential, while the rate of their inactivation is slowed down. The direct cause of the aconitine ectopic excitation are oscillations of the sodium current caused by modified channels. As a result of oscillations of the current, the membrane potential reaches the level of a regenerated response from time to time, after which generation of the excitation occurs.