Nicotine suppresses the neurotoxicity by MPP+/MPTP through activating α7nAChR/PI3K/Trx-1 and suppressing ER stress.

Parkinson's disease (PD) is a neurodegenerative disease. Nicotine has been reported to have the role in preventing Parkinson's disease. However, its mechanism is still unclear. In present study we found that nicotine suppressed 1-methyl-4-phenylpyridinium ion(MPP+) toxicity in PC12 cells by MTT assay. The expression of thioredoxin-1(Trx-1) was decreased by MPP+, which was restored by nicotine. The nicotine suppressed expressions of Glucose-regulated protein 78(GRP78/Bip) and C/EBP homologous protein (CHOP) induced by MPP+. The methyllycaconitine (MLA), the inhibitor of α7nAChR and LY294002, the inhibitor of phosphatidylinositol 3-kinase (PI3K) blocked the suppressions of above molecules, respectively. Consistently, pretreatment with nicotine ameliorated the motor ability, restored the declines of Trx-1 and tyrosine hydroxylase (TH), and suppressed the expressions of Bip and CHOP induced by 1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Our results suggest that nicotine plays role in resisting MPP+/MPTP neurotoxicity through activating the α7nAChR/PI3K/Trx-1 pathway and suppressing ER stress.