NMDA Receptors of Gastric-Projecting Neurons in the Dorsal Motor Nucleus of the Vagus Mediate the Regulation of Gastric Emptying by EA at Weishu (BL21)

Xin Zhang,Bing Zhu,Bin Cheng,Haifa Qiao,Xianghong Jing,Huijuan Yu,Xinyan Gao,Yongfa Qiao

doi:10.1155/2012/583479

Abstract

A large number of studies have been conducted to explore the efficacy of electroacupuncture (EA) for the treatment of gastrointestinal motility. While several lines of evidence addressed the basic mechanism of EA on gastrointestinal motility regarding effects of limb and abdomen points, the mechanism for effects of the back points on gastric motility still remains unclear. Here we report that the NMDA receptor (NMDAR) antagonist kynurenic acid inhibited the gastric emptying increase induced by high-intensity EA at BL21 and agonist NMDA enhanced the effect of the same treatment. EA at BL21 enhanced NMDAR, but not AMPA receptor (AMPAR) component of miniature excitatory postsynaptic current (mEPSC) in gastric-projecting neurons of the dorsal motor nucleus of the vagus (DMV). In sum, our data demonstrate an important role of NMDAR-mediated synaptic transmission of gastric-projecting DMV neurons in mediating EA at BL21-induced enhancement of gastric emptying.

Highlights

Functional gastrointestinal disorders are frequently encountered in ordinary clinical practice
We investigated the functional role of NMDA receptors (NMDARs) and Glutamate and γ-aminobutyric acid (GABA) receptors (GABARs) in this process and found that high-intensity EA at BL21 enhanced gastric emptying through NMDARs of dorsal motor nucleus of the vagus (DMV)
To identify the role of GABA receptors in regulation of gastric emptying by electrostimulation at BL21, we stereotaxically microinjected GABA receptor antagonists bicuculline and phaclofen through a glass micropipette into DMV 10 min before EA application

Summary

Introduction

Functional gastrointestinal disorders are frequently encountered in ordinary clinical practice. Microinjection of glutamate into the DMV enhanced gastric motility [13,14,15]. Microinjection of GABAA antagonists, bicuculline, into the DMV induces dose-dependent increases in gastric motility and secretion [16,17,18]. Microinjection of GABAA agonist, muscimol, into the DMV abolished bicuculline-induced increases in gastric motility and gastric acid secretion [17, 18]. GABAB receptor antagonist, baclofen, induced outward current of the Evidence-Based Complementary and Alternative Medicine gastric-projecting neurons at the DMV [19]. We investigated the functional role of NMDA receptors (NMDARs) and GABA receptors (GABARs) in this process and found that high-intensity EA at BL21 enhanced gastric emptying through NMDARs of DMV

Methods

Results

Conclusion