title: Perceptual responses in patients with inflammatory and functional bowel disease.
abstract: OBJECTIVE
  Enhanced visceral sensitivity following a transient inflammatory process in the gut has been postulated as an aetiological mechanism of irritable bowel syndrome (IBS). In this study we compared perceptual responses to rectosigmoid distension in patients with mild chronic inflammation of the rectum (ulcerative colitis (UC)) and patients without mucosal inflammation (IBS) to determine if chronic low grade mucosal inflammation may be a plausible explanation for rectosigmoid hypersensitivity reported in both IBS and UC patients.
  
  
  METHODS
  UC disease activity was quantified using activity index scores. Perception thresholds for discomfort during rectosigmoid distension were compared between 11 UC patients with quiescent or mild disease activity, 18 IBS patients, and 13 healthy controls.
  
  
  RESULTS
  Although UC activity index scores negatively correlated with perceptual thresholds for discomfort (r=-0.76, p=0.016), UC patients had higher discomfort thresholds compared with IBS patients and controls before (p=0.02) and after (p<0.001) a noxious sigmoid conditioning stimulus.
  
  
  CONCLUSIONS
  Rectal perception was attenuated in UC but enhanced in IBS. In chronic mild inflammation, activation of antinociceptive mechanisms may prevent the development of visceral hyperalgesia. Low grade mucosal inflammation alone is unlikely to be responsible for symptoms in functional gastrointestinal disorders.
authors.affiliation: UCLA/CURE Neuroenteric Disease Program, Department of Medicine and Physiology, UCLA School of Medicine, Los Angeles, California 90073, USA. linchang@ucla.edu
authors.forename: L
authors.initials: L
authors.lastname: Chang
authors.forename: J
authors.initials: J
authors.lastname: Munakata
authors.forename: E A
authors.initials: EA
authors.lastname: Mayer
authors.forename: M J
authors.initials: MJ
authors.lastname: Schmulson
authors.forename: T D
authors.initials: TD
authors.lastname: Johnson
authors.forename: C N
authors.initials: CN
authors.lastname: Bernstein
authors.forename: L
authors.initials: L
authors.lastname: Saba
authors.forename: B
authors.initials: B
authors.lastname: Naliboff
authors.forename: P A
authors.initials: PA
authors.lastname: Anton
authors.forename: K
authors.initials: K
authors.lastname: Matin
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002404:Catheterization; D003093:Colitis, Ulcerative / Q000503:physiopathology*; D003109:Colonic Diseases, Functional / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D010465:Perception; D012720:Severity of Illness Index