Fig. 4.

Electrophysiological analysis of the expression of the α_1A calcium channel with normal and expanded number of CAG repeats. B, Ba²⁺ currents evoked by 100 msec depolarizing pulses from a holding potential (V_h) of −90 mV to test potentials (V_test) of −40 to +50 mV with 5 mV steps. Top row, Currents originated from α_1A channels with normal number of repeats (WT): CAG₄ and CAG₁₁. Bottom row, Currents from cells expressing mutant channel repeats (EXP): CAG₂₃, CAG₂₇, and CAG₇₂. The current–voltage relationship (I–V curve) for all five samples is shown in the top row. The symbols used for each construct throughout this study are depicted above each currenttrace.