Fig. 3.

Antimycin-A and CCCP, but not oligomycin, inhibited PMCA activity. As in Figs. 1 and 2, cells were pretreated with Ru-360 (10 μM for 30 min) to inhibit mitochondrial Ca²⁺ uptake in all experiments. Representative traces show control cells (A) and the effects of 4 μM CCCP (Bi and Bii), 0.5 μM antimycin-A (C), and 10 μM oligomycin (D). Arrows indicate the point at which CPA was added, which was then present throughout the experiment. In 60% of cells, CCCP evoked an increase in [Ca²⁺]_i when added in the absence of external Ca²⁺ (Bi) but had no effect in the remaining 40% of cells (Bii). E: mean data showing the standardized linear [Ca²⁺]_i clearance rate following treatment with each mitochondrial inhibitor (*P < 0.05, as assessed using an unpaired t-test). Con, control; Anti, antimycin; Oligo, oligomycin.