Agomelatine and Duloxetine Synergistically Modulates Apoptotic Pathway by Inhibiting Oxidative Stress Triggered Intracellular Calcium Entry in Neuronal PC12 Cells: Role of TRPM2 and Voltage-Gated Calcium Channels

Calcium ion (Ca2+) is one of the universal second messengers, which acts in a wide range of cellular processes. Results of recent studies indicated that ROS generated by depression leads to loss of endoplasmic reticulum-Ca2+ homeostasis, oxidative stress, and apoptosis. Agomelatine and duloxetine are novel antidepressant and antioxidant drugs and may reduce oxidative stress, apoptosis, and Ca2+ entry through TRPM2 and voltage-gated calcium channels. We tested the effects of agomelatine, duloxetine, and their combination on oxidative stress, Ca2+ influx, mitochondrial depolarization, apoptosis, and caspase values in the PC-12 neuronal cells. PC-12 neuronal cells were exposed in cell culture and exposed to appropriate non-toxic concentrations and incubation times for agomelatine were determined in the neurons by assessing cell viability. Then PC-12 cells were incubated with agomelatine and duloxetine for 24 h. Treatment of cultured PC-12 cells with agomelatine, duloxetine, and their combination results in a protection on apoptosis, caspase-3, caspase-9, mitochondrial membrane depolarization, cytosolic ROS production, glutathione peroxidase, reduced glutathione, and lipid peroxidation, values. Ca2+ entry through non-specific TRPM2 channel blocker (2-APB) and voltage-gated Ca2+ channel blockers (verapamil and diltiazem) was modulated by agomelatine and duloxetine. However, effects of duloxetine on the Ca2+ entry through TRPM2 channels were higher than in agomelatine. Results of current study suggest that the agomelatine and duloxetine are useful against apoptotic cell death and oxidative stress in PC-12 cells, which seem to be dependent on mitochondrial damage and increased levels of intracellular Ca2+ through activation of TRPM2 and voltage-gated Ca2+ channels.