Lack of effect of Bcl-x_L over expression on ionomycin-mediated increase in Ca²⁺ levels.

a) Time-course of Ca²⁺ levels, expressed as percentage of maximum Ca²⁺ response, following ionomycin (2 µM; arrow) addition to SH-SY5Y/Neo (solid lines) and SH-SY5Y/Bcl-x_L cells (dashed lines). Following an initial Ca²⁺ peak, a late Ca²⁺ increase occurs reaching a plateau that is taken as the maximum Ca²⁺ level for the neuron. b) Cytoplasmatic response to ionomycin treatment (2 µM) in SH-SY5Y/Neo (n = 10) and SH-SY5Y/Bcl-x_L (n = 11) cells measured as the ratio of the early Ca²⁺ peak to the maximal ionomycin signal obtained during each individual experiment. Data represent mean ± S.E.M of the indicated number of experiments.