Figure 3.

A463C is sufficient for large sodium currents to be observed in the absence of potassium. In all panels, the current sweeps are from outside-out patches and were elicited by voltage ramps from −100 to +200 mV. The pipette solution contained 140 mM NaCl, 0 KCl in all experiments. #1 in all three panels is the current elicited in the presence of 140 mM external KCl. #2 is the current elicited in the presence of 140 mM external NMGCl. S460G (A) and T469V (C) do not readily conduct sodium in the absence of potassium. A463C (B), however, readily conducts sodium in the absence of potassium. The observed sodium current is blocked by 140 mM external TEA (#3).