Paroxetine inhibits lipopolysaccharide (LPS)-induced nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in BV2 cells. Cells were pretreated with paroxetine at 0, 0.1, 0.2, 1 or 5 μM for 30 min and then stimulated with LPS at 100 ng/ml for 24 hours. (A) Measurement of nitrite in culture media as an indicator of NO production. (B) Western blot analysis of iNOS expression. The protein levels were quantified and normalized with their respective β-actin levels. Each value was then expressed relative to the one treated with LPS alone, which was set as 100. *P < 0.05 versus treated with LPS alone. Values are means ± SE of three independent experiments. PAR, paroxetine; LPS, lipopolysaccharide; NO, nitric oxide; iNOS, inducible nitric oxide synthase.