Effect of KCl-induced depolarization and thapsigargin treatment in C2C12 WT and PV-clones on mitochondrial membrane potential, [Ca²⁺]_m and

<p><b>[Ca²⁺]_c.</b> A) Representative (normalized) traces of rhod123-loaded C2C12 cells (WT, black line and PV-clone, gray line) exposed to nominally 100 mM KCl for 15 s starting at 30 s. Higher values indicate a decrease in intramitochondrial membrane potential (Δψ_m). The average basal fluorescence before treatment (0–20 s) was subtracted. B) A similar experiment with cells exposed to nominally 300 mM KCl for 60 s starting at 40 s. The actual KCl concentration sensed by the cells is estimated to be less than half of the nominal concentration due to dilution with basal medium. C) Representative traces of rhod-2-loaded C2C12 cells (WT, black line and PV-clone, gray line) exposed to nominally 300 mM KCl for 60 s starting at 40 s. Higher values indicate an increase in [Ca²⁺]_m. Changes in fluorescence are reported as F/F₀, where F₀ is the baseline reached before drug application. Quantitative data is presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044837#pone-0044837-t002" target="_blank">Table 2</a>. D) WT and PV-clones were treated with thapsigargin (1 µM) and [Ca²⁺]_c was recorded with Fura-2; representative traces are shown, quantitative data (n = 9 cells, both from WT and PV-clones from 3 independent experiments) is presented in the Results section. Note the different time scales in A, B&C and D.