Fig. 2. Effect of antidepressants on alkaline phosphatase activity. Alkaline phosphatase activity was measured in human mesenchymal stem cells (MSCs) that had been induced to differentiate into osteoblasts over 3 weeks at 37℃ in the presence of various concentrations of (A) amitriptyline, (B) venlafaxine, or (C) fluoxetine. Differentiating cells were also incubated with vehicle (VEH) alone, while undifferentiated cells were incubated with MSC growth media (GM) for 3 weeks as controls. Alkaline phosphatase activity is displayed relative to VEH control. Data are representative of 3 to 6 independent experiments per drug. ^*P<0.05 compared to VEH-treated cells.