Fig. 5

Inflammatory cytokines downregulate the protein expression of OT/OTR in enteric neurons via the STAT3 or NF-κB pathway. A–D Cultured enteric neurons were pretreated with or without Stattic (STAT3 inhibitor, 5 μM) for 12 h followed by IL6 (10 ng/ml) or TNF-α (20 ng/ml) for 24 h. The levels of phosphorylated STAT3 (p-STAT3), total STAT3, OT, and OTR were analysed by western blot, and β-actin was used to evaluate protein loading. IL-6 (10 ng/ml) or TNF-α (20 ng/ml) decreased the expression of OT and OTR by activating the STAT3 pathway. E, F Cultured enteric neurons were pretreated with or without Bay11-7082 (NF-κB inhibitor, 1 μM) for 2 h followed by IL-1β (1 ng/ml) for 24 h. The levels of phosphorylated NF-κB (p-p65), total NF-κB (p65), OT, and OTR were analysed by western blot, and β-actin was used to evaluate protein loading. IL-1β (1 ng/ml) decreased the expression of OT and OTR by activating the NF-κB pathway. Values represent the mean ± SEM of 6 samples and were compared by one-way ANOVA with Newman–Keuls for multiple comparisons. *p < 0.05, **p < 0.01, ***p < 0.001