Anti-Parkinson's disease effects of ketamine via inhibiting protein kinase B/mammalian target of rapamycin signal pathway and triggering autophagy in rat B103 neuroblastoma cells

Objective To investigate the effect and molecular mechanism of ketamine on anti-Parkinson's disease(PD) on rat B103 neuroblastoma cells. Methods B103 cells were used as the experimental models. After the treatment with ketamine at the concentration of 0, 100, 200, 400 μmol/L and 400 μmol/L ketamine+5 mmol/L 3-methyladenine (3-MA), cell proliferation effects of ketamine were detected using 3-(4,5-dimenthyl-2-thiazolyl) -2,5-diphenyl-2-H-tetrazolium bromide(MTT) assay. Autophagy was detected with acridine orange staining and Lyso-Tracker Red staining using fluorescence microscopy. Expression of the proteins associated with Beclin-1, microtubulesas sociated protein light(LC3), protein kinase B(Akt), p70S6K, mammalian target of rapamycin (mTOR), α-synuclein (α-syn) and β-synuclein (β-syn) was evaluated using Western blot. Results The proliferation of B103 cells had no significant influence after treatment with ketamine (100, 200, 400 μmol/L) vs 0 μmol/L for 7 d (P>0.05). Acridine orange staining and Lyso-Tracker Red staining showed that ketamine triggered B103 cell autophagy in a dose-dependent manner (P<0.05). Western blot results showed that the expression levels of LC3-Ⅰ, phospho(p)-Akt, p-p70S6K and p-mTOR were lower in 400 μmol/L than the levels in 0 μmol/L. The expression levels of LC3-Ⅱand Beclin-1 were higher in 400 μmol/L than expression levels in 0 μmol/L (P<0.05). Expression levels of Parkinson's disease marker protein α-syn decreased and β-syn were higher in 400 μmol/L than 0 μmol/L (P<0.05). After pretreatment with 3-MA(5 mmol/L), the anti-PD effect of ketamine on B103 cells was reversed (400 μmol/L+3-MA and 400 μmol/L, P<0.05). Conclusions Ketamine exerts anti-PD effect by inhibiting Akt/mTOR signaling pathway, inducing autophagy in B103 cells and degrading α-syn. Key words: Ketamine; Parkinson's disease; Autophagy; Protein kinase B/mammalian target of rapamycin signaling transduction pathway