Upregulation of Gastric Norepinephrine With β-Adrenoceptors and Gastric Dysmotility in a Rat Model of Functional Dyspepsia

Abstract

Disordered motility is one of the most important pathogenic characteristics of unctional dyspepsia (FD), although the underlying mechanisms remain unclear. Since the sympathetic system is important to the regulation of gastrointestinal motility, the present study aimed to investigate the role of norepinephrine (NE) and adrenoceptors in disordered gastric motility in a rat model with FD. The effect of exogenous NE on gastric motility in control and FD rats was measured through an organ bath study. The expression and distribution of β-adrenoceptors were examined by real-time PCR, Western blotting and immunofluorescence. The results showed that endogenous gastric NE was elevated in FD rats, and hyperreactivity of gastric smooth muscle to NE and delayed gastric emptying were observed in the rat model of FD. The mRNA levels of β1-adrenoceptor and norepinephrine transporter (NET) and the protein levels of β2-adrenoceptor and NET were increased significantly in the gastric corpus of FD rats. All three subtypes of β-adrenoceptors were abundantly distributed in the gastric corpus of rats. In conclusion, the enhanced NE and β-adrenoceptors and NETs may be contributed to the disordered gastric motility in FD rats.