[Frequency-dependent blocking of single Na channels of cardiomyocytes with ethmozin]

Using a "patch-clamp" technique in "cell-attached" configuration, frequency-dependent blocking of single Na channels in the rat cardiomyocyte membrane with ethmozin was studied. It has been established that blocking effect of ethmozin on the integral sodium current in cardiac cellular membranes at increased stimulation frequency (from 1 to 5 Hz) was associated with the reduced likelihood of the existence of open Na channels. The patency of individual channels remained unchanged.