FIGURE 3.

Semilogarithmic plots of the average shifts in reversal potential, ΔV_rev, versus external Cl⁻ activity (on a log scale) for the anion-selective WT and P−2′Δ GlyR channels in 1, 0.5 and 0.25 LiCl, NaCl, and CsCl solutions. The solid lines show fits of the GHK equation (Eq. 2) to the ΔV_rev values, as used to determine P_Cl/P_Na averaged from individual experiments and shown in Figs. 1 and 2. The dashed lines indicate the ΔV_rev values expected if the counterion permeability had been zero. The errors shown, when larger than symbols, are the SEs.