AA inhibition stabilizes closed states of Ca_V1.3b. (A and B) Summary of average percent inhibition of Ca_V1.3b currents after a 1-min exposure to 10 µM AA from a holding potential of −90 mV (A) or −60 mV (B; n = 7–17; ***, P < 0.001 compared with CTL currents and P < 0.05 comparing percent inhibition by AA at −90 to −60 mV for all β subunits). (C) Time course of averaged TTP for Ca_V1.3b currents with β_2a (left) or β₃ (right) from a holding potential of −60 mV. (D) Protocol for studying AA inhibition in the absence of depolarizing test pulses (TP) from a holding potential of −60 mV. (E) Summary bar graph for percent inhibition by AA: left, with 40-ms test pulses; middle, with 10-ms test pulses; right, with no test pulses (n = 5–7; ***, P < 0.001 compared with CTL currents).