Effect of antimycin/oligomycin, FCCP, and cyclosporine A on the calcium-mobilizing activity of ST1926 in NB4 cells. Following preloading with the calcium fluorescent indicator FURA-2, NB4 cells (1 × 106/mL) were resuspended in PBS with calcium chloride at a concentr ation of 1.26 mM. Cells were placed in a cuvette under stirring at 37°C and changes in fluorescence were measured continuously with the use of a spectrophotofluorometer. Prior to addition of ST1926 at the concentration of 1 μM, NB4 cells were preincubated with vehicle (black tracing) or the following stimuli (gray tracings): a mixture of antimycin (1 μg/mL) and oligomycin (1 μg/mL) (Anti/Oligo; A), FCCP at the indicated concentrations (B), or cyclosporin A at the indicated concentrations (C). Each tracing is representative of at least 2 independent experiments run in triplicate.
