| Abstract: | Simultaneously, the effect of sodium-free medium and tetrodotoxin (3 X 10(-8) M/ml) were investigated on some passive electrophysiological properties of leech Retzius nerve cells. Complete replacement of Na+ with Tris or addition of tetrodotoxin to the leech Ringer was followed by an increase of input resistance in contrast to the cell-to-cell interaction which was not affected by such a procedure. At the same time tetrodotoxin was not able to block repetitive spike activity. The data imply the existence of two types of Na+ channel in leech Retzius nerve cells. |
