[Membrane currents induced by entrance of sodium ions into giant mollusk neurons].

Membrane currents induced by the intake of sodium ions during tetanic stimulation or steady depolarization under voltage clamp conditions were studied on giant neurons of the mollusc Helix pomatia. It is shown that the induced current may be separated into two components: the fast one having a reversal potential close to the EK level, and the slow one slightly dependent on the membrane potential in the region --50 divided by --90 mV Strophanthin K and replacement of external sodium with lithium or calcium ions eleminated for slow component and reduced the fast one. A conclusion is made that the slow component is produced by the activation of the electrogenic sodium pump, and the fast one-- by an increase in potassium permeability probably coupled to intensive activity of this pump.