Ca_v2.3 channel ionic and gating currents. (A) Mean ionic (left) and gating (right) current traces recorded from the same cells before and after Ca²⁺ substitution by Mg²⁺ and addition of 100 µM free La³⁺ (n = 18). Test potentials indicated next to the gating current traces have been corrected for the shift in channel voltage dependence produced by the La³⁺ used to suppress ionic currents. (B) Comparison of mean ionic (black) and gating (red) current traces after normalization by their maximum amplitudes to show that there was a significant fraction of charge movement that is too slow to be associated with channel opening (same cells as in A).