title: Brain-Derived Neurotrophic Factor Contributes to Colonic Hypermotility in a Chronic Stress Rat Model.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF) has prokinetic effects on gut motility and is increased in the colonic mucosa of irritable bowel syndrome.
  
  
  OBJECTIVE
  We aimed to investigate the possible involvement of BDNF in stress-induced colonic hypermotility.
  
  
  METHODS
  Male Wistar rats were exposed to daily 1-h water avoidance stress (WAS) or sham WAS for 10 consecutive days. The presence of BDNF and substance P (SP) in the colonic mucosa was determined using enzyme immunoassay kits. Immunohistochemistry and western blotting were performed to assess the expression of BDNF and its receptor, TrkB. The contractions of muscle strips were studied in an organ bath system.
  
  
  RESULTS
  Repeated WAS increased the fecal pellet expulsion and spontaneous contractile activities of the colonic muscle strips. Both BDNF and SP in the colonic mucosa were elevated following WAS. Immunohistochemistry revealed the presence of BDNF and TrkB in the mucosa and myenteric plexus. BDNF and TrkB were both up-regulated in colon devoid of mucosa and submucosa from the stressed rats compared with the control. BDNF pretreatment caused an enhancement of the SP-induced contraction of the circular muscle (CM) strips. TrkB antibody significantly inhibited the contraction of the colonic muscle strips and attenuated the excitatory effects of SP on contractions of the CM strips. Repeated WAS increased the contractile activities of the CM strips induced by SP after BDNF pretreatment, and this effect was reversed by TrkB antibody.
  
  
  CONCLUSIONS
  The colonic hypermotility induced by repeated WAS may be associated with the increased expression of endogenous BDNF and TrkB. BDNF may have potential clinical therapeutic use in modulating gut motility.
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, Number 238, Jiefang Road, Wuhan, 430060, Hubei Province, China, quanxiaojing77@126.com.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Quan
authors.forename: Hesheng
authors.initials: H
authors.lastname: Luo
authors.forename: Han
authors.initials: H
authors.lastname: Fan
authors.forename: Qincai
authors.initials: Q
authors.lastname: Tang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Ning
authors.initials: N
authors.lastname: Cui
authors.forename: Guang
authors.initials: G
authors.lastname: Yu
authors.forename: Hong
authors.initials: H
authors.lastname: Xia
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism / Q000502:physiology*; D003106:Colon / Q000502:physiology*; D005769:Gastrointestinal Motility / Q000502:physiology*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000502:physiology; D023421:Models, Animal; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology; D017208:Rats, Wistar; D013315:Stress, Psychological; D013373:Substance P / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D008562:Membrane Glycoproteins; D013373:Substance P