Fig. 6

The Smad2/3 pathway is involved in the upregulation of OT/OTR expression following TGF-β treatment. A–D Cultured enteric neurons were pretreated with or without SIS3CHL (Smad3 inhibitor, 5 μM) for 12 h followed by TGF-β (10 ng/ml) for 24 h. The levels of phosphorylated Smad2 (p-Smad2), phosphorylated Smad3 (p-Smad3), total Smad2, total Smad3, OT, and OTR were analysed by western blot, and β-actin was used to evaluate protein loading. TGF-β (10 ng/ml) increased the expression of OT and OTR by activating the Smad2/3 pathway. The 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