*A,* whole-cell currents from a cell expressing Ca_{V}2.2e[37a] showing the change in the ON gating currents at the reversal potential (+62.0 mV in this cell) following steps to various potentials (−100, −60, −10, +10 and +100 mV shown) from a holding potential of −100 mV. *B,* expanded ON gating currents at the reversal potential after a preceding step to −100 mV for a cell expressing Ca_{V}2.2e[37a] (•) and a cell expressing Ca_{V}2.2e[37b] (○). The decay of the gating current fitted with a single exponential and the time constant is the same for both isoforms (Ca_{V}2.2e[37a], 0.50 ± 0.01 ms, *n* = 18; Ca_{V}2.2e[37b], 0.53 ± 0.01 ms, *n* = 18). *C,* average total charge movement during ON gating current as a function of the preceding potential step for Ca_{V}2.2e[37a] (•, *n* = 18) and Ca_{V}2.2e[37b] (○, *n* = 18). The average charge moved is significantly different (*P* < 0.05) between the two isoforms from −100 to −60 mV. The curves are fitted with a Boltzmann function and the asymptotes at the hyperpolarized potentials are significantly different (*P* < 0.05): Ca_{V}2.2e[37a], 22.7 ± 1.0 fC pF^{−1}; Ca_{V}2.2e[37b], 15.5 ± 0.6 fC pF^{−1}. The other parameters from the individual fits are not significantly different. The asymptotes at depolarized potentials are 0.03 ± 0.09 fC pF^{−1} and −0.15 ± 0.08 fC pF^{−1}, *V*_{½} values are −12.3 ± 2.4 mV and −7.4 ± 2.0 mV, and *k* values are 10.3 ± 1.3 mV and 8.0 ± 1.2 mV for Ca_{V}2.2e[37a] and Ca_{V}2.2e[37b], respectively.

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