title: Effect of electroacupuncture stimulation at Zusanli acupoint (ST36) on gastric motility: possible through PKC and MAPK signal transduction pathways.
abstract: BACKGROUND
  Electroacupuncture (EA) stimulation has been shown to have a great therapeutic potential for treating gastrointestinal motility disorders. However, no evidence has clarified the mechanisms contributing to the effects of EA stimulation at the Zusanli acupoint (ST.36). This study was designed to investigate the regulative effect of EA stimulation at the ST.36 on gastric motility and to explore its possible mechanisms.
  
  
  METHODS
  Thirty Sprague-Dawley rats were randomly divided into three groups: the ST.36 group, the non-acupoint group, and the control group. EA stimulation was set at 2 Hz, continuous mode, and 1 V for 30 min. The frequency and average peak amplitude of gastric motility were measured by electrogastrography. The protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) signaling pathways were assessed using real-time polymerase chain reactions. Caldesmon (CaD) and calponin (CaP) protein expression in the gastric antrum were detected on Western blots. A Computed Video Processing System was used to evaluate morphological changes in smooth muscle cells (SMCs) from the gastric antrum.
  
  
  RESULTS
  EA stimulation at ST.36 had a dual effect on the frequency and average peak amplitude. Additionally, EA stimulation at ST.36 regulated the expression of some genes in the PKC and MAPK signaling pathways, and it regulated the expression of the CaD and CaP proteins. EA serum induced SMC contractility. Promotion of gastric motility may correlate with up-regulation of MAPK6 (ERK3), MAPK13, and Prostaglandin-endoperoxide synthase 2 (PTGS2) gene expression, and the down-regulation of the collagen, type I, alpha 1 (COL1A1) gene and CaD and CaP protein expression. Inhibition of gastric motility may correlate with down-regulation of the Interleukin-1 receptor type 2 (IL1R2) and Matrix metalloproteinase-9 (MMP9) genes, and up-regulation of CaD and CaP protein expression.
  
  
  CONCLUSIONS
  EA stimulation at ST.36 regulated gastric motility, and the effects were both promoting and inhibiting in rats. The possible mechanisms may correlate with the PKC and MAPK signal transduction pathways.
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang
authors.forename: Yan-Dong
authors.initials: YD
authors.lastname: Xie
authors.forename: Ming-xin
authors.initials: MX
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Huang
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.forename: Hui-Yan
authors.initials: HY
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Qin
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Huang
authors.affiliation: Department of Gastroenterology, Tangdu Hospital of the Forth Military Medical University, Xi'an, Shanxi 710038, China. jingjie@fmmu.edu.cn.
authors.forename: Jing-Jie
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D015669:Acupuncture Points; D000818:Animals; D015671:Electroacupuncture; D005769:Gastrointestinal Motility; D041981:Gastrointestinal Tract / Q000201:enzymology*; D015870:Gene Expression; D020935:MAP Kinase Signaling System; D008297:Male; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D011493:Protein Kinase C
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