Fig. 1.

Amitriptyline- and desipramine-induced SH-SY5Y cell death was not suppressed by inhibitors of known cell death pathways. To examine the mode of cell death induced by amitriptyline or desipramine, SH-SY5Y cells were preincubated with inhibitors of caspases [40 μM zVAD-fmk, (A)], Parp-1 [5 mM 3AB, (B)], calpain and cathepsin B/L [20 μM ALLM, (C)], cathepsins [10 μM E64, (D)] and autophagy [3 mM 3-MA, (E)] for 30 min. Amitriptyline (Ami) and desipramine (Desi) were then added at the indicated concentrations (in μM) and the cells further incubated for 24 h. Cell viability was measured using MTS reagent (n = 3). (F) SH-SY5Y cells were treated with amitriptyline (Ami, 60 μM), desipramine (Desi, 50 μM), or staurosporine as a positive control (STS, 1 μM) for 24 h and then processed for TUNEL to monitor apoptosis (n = 3, ^*p < 0.05, ^**p < 0.01 vs. vehicle treated; ns, not significant).