Ionomycin-induced Ca2+ overload is not accompanied by mitochondrial membrane potential dissipation in murine pro-B cells

There are extremely few data concerning the involvement of Ca2+ fluxes in the apoptosis of the pro-B cell type Ba/F3. Thus, we aimed the characterization of ionomycin-induced effects on Ba/F3 cells in vitro. Our obtained data show that cytosolic Ca2+ increased in Ba/F3 cells by 1 μM ionomycin in the presence of 1 mM Ca2+ for 24 hours did not induced significant effects on the mitochondrial membrane potential as compared with control cells. The same effects were also associated by the higher concentrations of ionomycin, e.g. 10 μM, in contrast with that induced by the treatment with staurosporine 10 μM. Thus, Ba/F3 cells are resistant toward the collapsing of mitochondrial membrane potential induced by cytosolic Ca2+ overload, as shown by the use of JC-1 fluorescent dye and laser confocal microscopy.