Figure 5. Biogenic amine (10 µM each) modulation of intracellular Ca²⁺ concentrations in HEK 293 cells constitutively expressing Am5-HT_2α or Am5-HT_2ß receptors and in non-transfected HEK 293 cells.

Cells were loaded with the Ca²⁺-sensitive dye Fluo-4 and changes in [Ca²⁺]_i were measured fluorimetrically. All values of HEK 293 cells stably expressing Am5-HT_2β (black bars) and the corresponding non-transfected HEK 293 cells (gray bars) were normalized to the serotonin response of the Am5-HT_2β-expressing cell line. The values obtained for the Am5-HT_2α cell line (white bar) and non-transfected HEK 293 cells (striped bar) were normalized analogously. Data represent the mean ± SD of octuplicate determinations from a representative experiment. The values for serotonin-stimulated Am5-HT_2α- and Am5-HT_2β-expressing cells are significantly different from all other values (one-way ANOVA, followed by Dunnett’s multiple comparison test, p < 0.05).