A. MTT assay shows that supernatants collected from microglia treated with gp120 (0.1nM) in presence of Meth (20µM) synergistically enhanced neuronal death. *p < 0.05, **p < 0.01, ***p < 0.001 vs ctrl, #p < 0.05 vs Meth (20µM)+gp120 (0.1nM). Data represent the mean ± SD in three independent experiments and analyzed using two-way ANOVA followed by Dunnett’s test. B and C. Tunel staining reveals PAP (10nM) or 4-AP (0.5µM) significantly decreased Meth+gp120-induced neuronal apoptosis. Scale bar represents 50µM. *p <0.05, ***p < 0.001 vs ctrl, #p < 0.05, ###p <0.001 vs Meth+gp120.