Effect of LPS on activation of p38, ERK1/2 and JNK MAPKs in neuronal and mixed glial cultures. Glial (a) or neuronal (b) primary cultures were left untreated (UT) or were treated with LPS (10 ng/ml) for 15, 30, 60 or 120 min. Cell lysates were assayed for p38, ERK1/2 and JNK activation by Western blot analysis. Levels of phosphorylated MAPKs were analyzed semi-quantitatively, normalized relative to total MAPKs, and presented as fold increase compared to untreated cultures. Data are presented as mean ± SD of at least three independent experiments carried out on separate cultures. *P <0.05, **P <0.01, ***P <0.001, LPS-treated versus untreated cultures, using one-way ANOVA and Tukey’s multiple comparison post-hoc test. ANOVA, analysis of variance; ERK1/2, extracellular-signal regulated kinase 1/2; JNK, c-Jun-N-terminal kinase; LPS, lipopolysaccharide; MAPK, mitogen-activated protein kinase.