FIGURE 2.

Concentration and voltage dependence of block by ions. (A) Fractional unitary current remaining (i/i₀) after addition of different concentrations of to the intracellular or extracellular solution: (•) internal , −50 mV; (○) internal , +50 mV; (▾) external , −50 mV; (∇) external , +50 mV. Each of these four sets of data has been fitted by Eq. 1. (B) Mean K_d calculated from curves such as those shown in (A) for both internal (•) and external (○) . Mean of data from 3–5 patches. Asterisks indicate a statistically significant difference from the K_d for internal .