LS8 cells, cultured in 2% FBS-DMEM, were treated with 10 ng/ml r[A−4] for 4 h. Panel A: total nitrites were quantitated spectrophotometrically with the Griess reagent, analyzed by linear regression, and expressed as µmoles/mg cellular protein. To confirm NOS2-mediated production of NO, LS8 cells were pre-treated with 0.5 mM L-Nil, followed by 10 ng/ml r[A−4]. Panel B: the expression of M180 mRNA was analyzed by semi-quantitative real-time PCR, and target mRNA expression was normalized to GAPDH mRNA expression, according to the ΔCt method. The histogram depicts one representative change in M180 expression (expressed as %) in the sample treated with r[A−4] vs. the sample co-treated with L-Nil and r[A−4].