Fig. 3

L-type currents and charge movements are reduced in symptomatic SOD1^G93A FDB fibers. Representative whole-cell recordings of L-type currents elicited by 500 ms step depolarizations from −80 to −20, 0, 20, and 40 mV are shown for a wild-type FDB fiber (a) and a symptomatic SOD1^G93A fiber (b). c Peak I-V relationships corresponding to the current families shown in panels (a) and (b). Currents were evoked at 0.1 Hz by test potentials ranging from −40 mV through +80 mV in 10 mV increments. Representative recordings of intramembrane charge movements elicited by 25 ms depolarizations from −80 to −40, −20, 0, and 20 mV are shown for a wild-type (d) and a symptomatic SOD1^G93A fiber (e). f Q-V relationships corresponding to the charge movements shown in panels (d) and (e). Charge movements were evoked at 0.1 Hz by test potentials ranging from −70 mV through +50 mV in 10 mV increments. The smooth curves in panels (c) and (f) are plotted according to Eqs. 2 and 3, respectively, with fit parameters displayed in Table 2