Fig. 5.

Effect of SPT and ASMase inhibition on cell viability and cell death in melatonin-HepG2 treated cells. Cells pre-treated with imipramine 10 μM or myriocin 2.5 μM were incubated with melatonin 2 mM until 48 hours. Annexin V-propidium iodide assay determinated low cell viability when cells were pre-treated with myriocin and a parcial rise when ASMase was inhibited (A). Viability was determined by MTT assay, showing a decrease in cell viability in myriocin plus melatonin group, but a recovery of viability in imipramine co-treated cells (B). Data are expressed as a percentage of mean values ± SEM of three independent experiments. *P < 0.05 significant differences vs control cells #P < 0.05 significant differences vs melatonin-treated cells.