Fig. 1

EC coupling is impaired in symptomatic global SOD1^G93A FDB fibers. Representative voltage-induced myoplasmic Ca²⁺ transients elicited by 25 ms depolarizations from −80 to −60, −40, −20, 0, and 20 mV from FDB fibers harvested from a wild-type C57BL/6J mouse (a) and a symptomatic SOD1^G93A mouse (b). The peak ΔF/F-V relationships for wild-type and symptomatic SOD ^G93A fibers are presented in panel (c). Ca²⁺ transients were evoked at 0.1 Hz by test potentials ranging from −70 mV through +60 mV in 10 mV increments. The smooth curves are plotted according to Eq. 1 with the respective fit parameters shown in Table 1. The numbers of analyzed fibers are indicated in parentheses. Throughout, error bars represent ± SEM