SSRIs trigger Ca²⁺ flux, tyrosine phosphorylation, and down-regulation of c-

myc and nm23 genes in group I BL cells. [Ca²⁺]_I measurements in L3055 cells treated with (A) 0.5 to 80 μM fluoxetine; (B) 20 μM fluoxetine; (C) 20 μM paroxetine; (D) 100 μM citalopram; (E) 100 nM thapsigargin (Thg) followed by 20 μM fluoxetine in Ca²⁺-low medium (addition of 20 μM fluoxetine alone in Ca²⁺-low medium indicated in insert); (F) 20 μM fluoxetine in the presence or absence of 9 mM EGTA; and (G) 20 μM fluoxetine in the presence or absence of 1 mM of 5-HT. Each result either is representative or means ± SEMs of 3 experiments. (H) Western blotting analysis for protein phosphotyrosine in L3055 cells showing control (C) cultures and following treatment with 20 μM fluoxetine (Fl) or 10 μg/mL anti-μ chain antibody (Ig) for 60, 150, or 300 seconds. Blot is representative of 4 different experiments. (I) Real-time quantitative PCR analysis of indicated genes after 6 hours exposure of L3055 cells to 20 μM fluoxetine. Relative gene expressions normalized to L3055 control cultures (100%). Data are the means ± SEMs of 4 experiments each performed in triplicate.