title: Amitriptyline modifies the visceral hypersensitivity response to acute stress in the irritable bowel syndrome.
abstract: BACKGROUND
  Acute physical stress causes alteration in gut autonomic function and visceral hypersensitivity in patients with irritable bowel syndrome (IBS). We have developed a model to measure this stress response.
  
  
  OBJECTIVE
  To assess whether treatment with a drug effective in treating IBS (amitriptyline) alters the response to acute stress in IBS patients.
  
  
  METHODS
  Nineteen patients with IBS were given amitriptyline 25-50 mg. Patients underwent physical stress (cold pressor) test at baseline and after 3 months of treatment. Physiological parameters measured were: stress perception; systemic autonomic tone [heart rate (HR) and blood pressure (BP)]; gut specific autonomic innervation [rectal mucosal blood flow (RMBF)] and visceral sensitivity (rectal electrosensitivity).
  
  
  RESULTS
  Fourteen of 19 (74%) patients improved symptomatically after 3 months of amitriptyline. Acute stress induced increased perception of stress and systemic autonomic tone and reduced RMBF in symptomatic responders and nonresponders (P > 0.05 for all). All nonresponders but only 3 of 14 responders continued to exhibit stress-induced reduced pain threshold at 3 months (change from baseline -31% vs. +2%, P < 0.03 respectively).
  
  
  CONCLUSIONS
  In this open study, amitriptyline appears to decrease stress-induced electrical hypersensitivity; this effect is independent of autonomic tone. The gut response to acute stress deserves further study as a model to study drug efficacy in IBS.
authors.affiliation: GI Physiology Unit, University College Hospital, London, UK.
authors.forename: N M
authors.initials: NM
authors.lastname: Thoua
authors.forename: C D R
authors.initials: CD
authors.lastname: Murray
authors.forename: W J
authors.initials: WJ
authors.lastname: Winchester
authors.forename: A J
authors.initials: AJ
authors.lastname: Roy
authors.forename: M C L
authors.initials: MC
authors.lastname: Pitcher
authors.forename: M A
authors.initials: MA
authors.lastname: Kamm
authors.forename: A V
authors.initials: AV
authors.lastname: Emmanuel
mesh_terms: D000328:Adult; D000639:Amitriptyline / Q000627:therapeutic use*; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000188:drug therapy* / Q000503:physiopathology; D043183:Irritable Bowel Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D012007:Rectum / Q000187:drug effects* / Q000503:physiopathology; D013223:Statistics as Topic; D014781:Viscera / Q000187:drug effects* / Q000503:physiopathology; D055815:Young Adult
chemical_list: D018712:Analgesics, Non-Narcotic; D000639:Amitriptyline