[Action of a new antiarrhythmia preparation, etmozin, on the contractile force, transmembrane action potential and the rapid incoming sodium flow of the frog atrial muscle].

The mechanism of the effect of ethmosine on the force of contraction, the membrane potential and the rapid incoming sodium flow of the frog atrium was studied by means of microelectrode technique and the method of potential fixation. It has been shown that in a concentration of up to 10(-5) g/ml ethmosine reduces the rate of increase of the foremost front of the action potential by 50%; has no substantial effect on the force of contraction, and on the shape and duration of the transmembrane action potential; inhibits the rapid incoming sodium flow by more than 50% by diminishing maximum conductivity of sodium ions; has no effect on processes of activation, inactivation and reactivation of the sodium flow. A comparison is made between ethmosine and other antiarrhythmic agents in their effect on the force of contraction and the electric parameters of cardiac cells.