Pioglitazone inhibits LPS-induced iNOS expression, and iNOS inhibition protects dopaminergic neurons from LPS insults. Rat mesencephalic mixed cultures were treated with 1 μg/ml LPS for 48 hours. A: LPS treatment upregulated the expression of iNOS, and pretreatment with pioglitazone (10 μM), 1 hr before LPS, prevents its expression. B: Rat mesencephalic mixed cultures were treated with the selective iNOS inhibitor 1400 W, with different doses from 1 ng/ml to 10 μM/ml, 1 hr before a 72 hr LPS exposure. The number of TH-positive neurons was determined by immunocytochemistry. Data presented are representative of three independent experiments (n = 3). (**p < 0.01 vs. control, ***p < 0.001 vs. control, #p < 0.05 vs. LPS, ##p < 0.01 vs. LPS, ###p < 0.001 vs. LPS).