Fig. 4

Effect of SOD1 and ApoSOD1 on NCX1-mediated currents (I_NCX) and ER Ca²⁺ content in rat primary motor neurons. A Superimposed traces of I_NCX recorded by patch-clamp in rat primary motor neurons perfused with SOD1 and previously transfected with siControl (control) or siRNA against NCX1 (siNCX1; 10 nmol/L for 48 h). B Superimposed traces of I_NCX recorded by patch-clamp in rat primary motor neurons perfused with ApoSOD1 and previously transfected with siControl (control) or siRNA against NCX1 (siNCX1). C Quantification of A (n = 20 cells for each group) and B (n = 15 cells for each group). All the experiments were repeated at least three times; *p < 0.05 versus siControl (control); ** p < 0.05 versus SOD1 or ApoSOD1 alone. D Effect of SOD1 and ApoSOD1 preincubation (10 min) on ER Ca²⁺ content in the absence or presence of siNCX1 (10 nmol/L for 48 h). ER Ca²⁺ content has been measured in Fura 2-loaded motor neurons by adding ATP (100 µM) and thapsigargin (1 µM) in a Ca²⁺-free solution containing EGTA. Quantification has been reported as Δ% of increase in n = 30 cells for each group recorded in 3 independent experiments. *p < 0.05 versus siControl (control); **P < 0.05 versus All. E Superimposed representative traces of control motor neurons (siControl), motor neurons preincubated with SOD1 (10 min) or siNCX1-transfected neurons exposed to ATP and thapsigargin in a Ca²⁺-free solution containing EGTA. Inset: Representative Western blotting of GRP78 expression in control (siControl) and siNCX1-treated motor neurons (protein expression in control = 1 ± 0.001 and in siNCX1 = 3 ± 0.004 *p < 0.05)