Voltage-activated Ca _V 1.1 Ca ²⁺ current in WT and DMD ^mdx muscle fibers. (A) Representative examples of Ca²⁺ current traces in the two groups, in response to the indicated pulse protocol. (B) Values for the peak Ca²⁺ current versus voltage in WT and DMD^mdx fibers (data are from 29 fibers from seven WT animals and 27 fibers from seven DMD^mdx animals). For the sake of clarity, only mean (±SD) values from fibers from a same animal are shown. (C) Individual and corresponding mean (±SD) values for the parameters (G_max the maximum conductance, V_0.5 the mid-voltage, V_rev the reversal potential, and k the slope factor) fitted from the peak current versus voltage relationship in each fiber. Each bar and superimposed data points correspond to data from a same animal. For G_max, V_0.5, V_rev, and k, P = 0.85, 0.79, 0.79, and 0.29, respectively (nested t tests, corresponding 95% CIs for the difference between mean values: −0.035 to 0.029, −6.83 to 5.32, −9.58 to 7.46, and −0.77 to 2.39, respectively). 95% CI, 95% confidence interval.