title: Effect of estrogen on visceral sensory function in a non-inflammatory colonic hypersensitivity rat model.
abstract: BACKGROUND
  Increased prevalence of functional gastrointestinal disorders in women and perimenstrually accentuated symptoms imply that sexual hormones play a crucial role in the pathogenesis of such syndromes. The aim of this study was to analyze the selective effect of estrogen on visceral sensitivity in gonadectomized female and male Lewis rats with or without prior treatment with butyrate enemas.
  
  
  METHODS
  Following ovariectomy (OVX) or orchiectomy (ORX) estradiol pellets (E2-P) or sham pellets (Sham-P) were implanted. After treatment with butyrate (BUT) or saline (NaCl) enemas, colorectal distensions (CRD) were performed and the visceromotor reflex (VMR) to CRD was measured by electromyography.
  
  
  RESULTS
  Gender did not influence VMR to CRD in gonadectomized animals. VMR in E2-P animals compared to Sham-P animals was increased (635 ± 32 μVs vs 470 ± 39 μVs; p = 0.002). Overall, instillation of butyrate enemas did not influence VMR to CRD. A comparison of CRD clusters showed that butyrate enemas in the E2-P animals resulted in a significant sensitization in both OVX and ORX animals. In female rats, sensitization was also caused by estrogen substitution alone.
  
  
  CONCLUSIONS
  In our animal model, estrogen is a strong factor for an increase in visceral sensory function. Surprisingly, the treatment with butyrate alone did not evoke a general rise in VMR to CRD. Rats treated with butyrate enemas and under selective estrogen substitution developed visceral sensitization during the series of CRDs.
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Knuesel
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Oulevey-Meier
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Flogerzi
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Krayer
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: I
authors.initials: I
authors.lastname: Gschossmann
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Miller
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Tovar
authors.affiliation: Department of Statistics and Econometry, University of Bamberg, Bamberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Janko
authors.affiliation: Department of Visceral Surgery and Medicine, Inselspital/University of Berne, Berne, Switzerland. juergen.gschossmann@klinikum-forchheim.de.|Department of Clinical Research, Inselspital/University of Berne, Berne, Switzerland. juergen.gschossmann@klinikum-forchheim.de.
authors.forename: J M
authors.identifier: http://orcid.org/0000-0001-5705-3726
authors.initials: JM
authors.lastname: Gschossmann
mesh_terms: D000818:Animals; D003106:Colon; D004195:Disease Models, Animal; D004343:Drug Implants / Q000008:administration & dosage; D004967:Estrogens / Q000008:administration & dosage*; D005260:Female; D006930:Hyperalgesia / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D051381:Rats; D011917:Rats, Inbred Lew; D012737:Sex Factors; D016896:Treatment Outcome; D059265:Visceral Pain / Q000188:drug therapy* / Q000503:physiopathology*
chemical_list: D004343:Drug Implants; D004967:Estrogens
keywords: colorectal distension; electromyography; estrogen; functional bowel disorders; nociception; visceral sensory function