Figure 3.

Concentration dependence of potassium inhibition on Kv7.1. (A) Representative currents recorded at 40 mV at various concentrations of extracellular potassium. (B) Steady-state current amplitudes measured at the end of the 3-s step to 40 mV. The current amplitude is plotted as a function of time (20-s intervals) as the potassium concentration was varied as indicated. The representative traces in panel A correspond to the points (indicated by the arrows). (C) Relative steady-state current amplitude as a function of potassium concentration as measured experimentally for Kv7.1 (squares) and theoretical values calculated from the GHK flux equation (triangles). The currents are normalized to the current measured in 1 mM [K⁺]_o. (D) Concentration-response curve for extracellular potassium. The relative current was corrected for the theoretical reduction and plotted as a function of log [K⁺]_o. A Hill-function was fitted to the data (solid line).