Evaluation of the antiparkinsonian effect of verapamil in in vitro parkinson's disease model through mitochondrial dysfunction

Verapamil, a phenylalkylamine derivative, is a calcium channel blocker. It has been determined that a common feature of neurodegenerative diseases is calcium signaling dysregulation. Increased Ca2+ ion concentration in the cell disrupts intracellular function, leading to mitochondrial dysfunction, increased oxidative stress, and plays an important role in the development of Parkinson's disease (PD). In various studies, it has been determined that verapamil has a neuroprotective effect in various acute neurotoxicity models by blocking calcium entry into neurons. It has also been observed that verapamil has antihypertensive, antianginal and antiarrhythmic properties. In this study, the antiparkinson effect of verapamil in the in vitro PH model was evaluated based on mitochondrial dysfunction. The in vitro PH model in SH-SY5Y cells was established using 6-hydroxydopamine (6-OHDA). Then, the cytotoxic effect of verapamil on SH-SY5Y cells and its neuroprotective effect against 6-OHDA-induced toxicity were investigated by XTT analysis. Considering the cytotoxicity results, in subsequent analysis cells were pretreated with 10 µM verapamil for 6 hours, followed by 150 µM 6-OHDA for 24 hours. Afterwards, intracellular reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were determined; superoxide dismutase (SOD) and catalase (CAT) antioxidant enzyme activities were analyzed, and the expression levels of genes related to PH and mitochondria function were evaluated by qRT-PCR analysis in the experimental groups. According to the results, 6-OHDA treatment increased the ROS level and decreased MMP, and also caused a significant decrease in SOD activity in SH-SH5Y cells compared to control group. On the other hand, when compared to the 6-OHDA group, verapamil treatment decreased ROS level and increased SOD enzyme activity. It has also been determined that 6-OHDA and verapamil can modulate the expression levels of various genes related to mitochondrial function and PH. In conclusion, this study revealed that verapamil regulates mitochondria function by causing a decrease in oxidative stress and has a neuroprotective effect in in vitro PH model. Keywords: Parkinson's disease, Verapamil, 6-hydroxydopamine.