Effect of atropine on 5-HT-induced contraction. Atropine (1 μM) was added 1 hour before administration of the 5-HT concentration effect curves. Fresh (A), 4 days of organ culture in the absence (B) and presence (C) of IL-1β (10 ng/ml). Each data point is derived from 6–11 experiments and represented as the 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, no differences were seen (Fig. 6A-C, P > 0.05). In addition, unpaired Students' t-test with Welch's correction was applied for comparison of pEC50 values (curve shift) and maximal contraction of the two corresponding curves (see results).