MAPK inhibition. Effect of specific inhibitors for JNK (SP600125), ERK 1/2 (PD98059) or p38 (SB203580) on 5-HT induced contractions. Fresh (A), 4 days of organ culture in the absence (B) and presence (C) of IL-1β (10 ng/ml). The three inhibitors as well as the vehicle (DMSO) were added to the tissue bath 30 min before the first concentration of 5-HT. Each data point is derived from 5–6 experiments and represented as mean ± S.E.M. Statistical analysis was performed with two-way ANOVA with Bonferroni post-test to compare the two corresponding data points at each concentration of the two curves. *P < 0.05, compared with control.