Fig. 4. Effect of CAI and FCCP on mitochondrial inner-membrane potential (_m). (A) Following complete Ca²⁺ store depletion by perfusion with 10 µM TG in nominal Ca²⁺-containing solution for about 5 minutes, 5 mM Ca²⁺ was added to the perfusate (arrowhead) evoking an increase in [Ca²⁺]_m in control cells loaded with 2 µM Rhod-2/AM. This increase was greatly attenuated in loaded cells co-treated with 10 µM TG and 20 µM FCCP. (B) Application of CAI (10 µM) or FCCP (20 µM) inhibited _m compared with vehicle-treated (0.1% DMSO) controls as determined by JC-1 dye red-to-green fluorescence ratio. (C) Confocal images of JC-1-loaded (2 µg/ml) HEK-293 cells pretreated for 20 minutes with vehicle, CAI or FCCP. Bars, 10 µm.