Figure 2

Inhibition of WT Kir2.1 currents by intracellular Mg²⁺ in symmetrical 20 mM K⁺, 300 mM K⁺ and external 20/ internal 100 mM K⁺.

(a)The Kd of the intracellular Mg²⁺ block in symmetrical 20 and 300 mM K⁺ is plotted against voltage on a semi–logarithmic scale (data were obtained with the same approach as that in Fig. 1b). The Kd–voltage relationship of Mg²⁺ block in symmetrical 100 mM K⁺ (solid line) is taken from Fig. 1c for comparison. (b) The Kd–voltage relationship of Mg²⁺ block in external 20/internal 100 mM K⁺ is apparently similar to that in symmetrical 100 mM K⁺, but is shifted only by ~−20 mV in the voltage axis (data were obtained with the same approach as that shown in Fig. 1c).