Separation of gating pore current and central pore current for NaChBac R3C using blockers and inactivation. (A) Current traces like those in Fig. 4 B showing the decline in I_gp during steps to strongly hyperpolarized potentials. Colors and associated arrows indicate currents recorded at the indicated potentials, and numbers in parentheses highlight particular phases of each trace. Phase 1, inward gating pore current; phase 2, outward gating charge movement plus residual capacity transient; phase 3, inward central pore current. (B) Nifedipine block. An experiment like the one in A was performed in the absence (top) and presence (bottom) of 100 µM nifedipine. Arrows denote the central pore current. (C) Gating pore current at the beginning of the pulse is plotted in the absence (open triangles) and presence (closed triangles) of nifedipine.