[Formation of ectopic stimulation in the heart under the action of aconitine. I. The dynamics of input and output membrane currents].

Rapid sodium and slow input and output currents were studied by the double saccharose bridge method on isolated atrial trabeculae of Rana ridibunda under the effect of aconitin (100 mg/l). It is shown that the ptroperties of rapid sodium channels change under the effect of aconitin. As the result of this, activation of the input sodium current begins at potentials which are close to the rest potential, the maximum value of sodium conduction reduces, while the reverse potential for sodium current is shifted in the direction of lower potentials. Despite the effect of aconitin, the sodium current is blocked by tetrodotoxin (10-6M). Aconitin causes reversible reduction of the input calcium current but has no effect on the output current.