The role of T-type calcium channel in lidocalne-induced neuronal cytotoxicity

Objective To investigate the role of T-type calcium channel in lidocaine-induced neuronal cytotoxicity. Methods SH-SY5Y cell line was a gift from cell biology laboratory of our medical university. The cells were cultured in DMEM liquid culture medium at 37 ℃ in incubator filled with 5 % CO2, and randomly divided into 4 groups （ n = 66 each） ： control group （group C）and M, L and ML groups were exposed to 5 μmol/L mibefradil （a T-type calcium channel blocker）, 10 mmol/L lidocaine and 5 μmol/L mibefradil ＋ 10 mmol/L lidocaine for 24 h. Cell morphology was examined by electronic microscopy at 24 h of drug exposure. Cell viability （by MTT） and neuronal apoptosis （by flow cytometry） were detected immediately before and at 1, 6, 12 and 24 h of exposure to mibefradil or/and lidocaine. Results In C and M groups, the cells demonstrated dendritic protrusions, enlarged nerve processes and dense lattice. After being exposed to lidocaine for 24 h, the dendritic protrusions disappeared, the cells decreased in size, shrinked and became round; the cell viability was significantly decreased while the neuronal apoptosis increased. The lidocaine-induced changes were significantly attenuated by co-incubation with mibefradil. Conclusion T-type calcium channel is involved in lidocaine-induced neuronal cytotoxicity. Key words: Lidocaine ;  Calcium channel