Figure 9.

Effect of external K⁺ on Na⁺ current inactivation and deactivation. (A) Experimental procedure was identical to that of Fig. 3 (different cell). Currents in the absence of K⁺ and in the presence of 0.03 mM K⁺ were evoked by a 100-ms depolarization to 0 mV. (B) Three tail currents from the cell in A, normalized at the current measured 210 μs after repolarization and plotted on an expanded scale. Currents were recorded at −80 mV in the presence of 0, 0.03, and 10 mM K⁺.