title: A 5HT3 antagonist corrects the postprandial colonic hypertonic response in carcinoid diarrhea.
abstract: OBJECTIVE
  Carcinoid patients show a hypertonic colonic motor response postprandially. Ondansetron reduces postprandial colonic tone in health. It was hypothesized that ondansetron, a selective 5HT3 antagonist, corrects the colonic motor response to eating in carcinoid diarrhea.
  
  
  METHODS
  The effects of ondansetron and placebo on fasting and postprandial colonic tone and motility in 10 patients with carcinoid diarrhea were compared using a manometry-barostat assembly positioned in the upper descending colon.
  
  
  RESULTS
  Fasting colonic tone and motility indices were similar in the placebo and ondansetron groups; ondansetron did not affect fasting motility. The placebo group showed a significant reduction in barostat balloon volume (signifying increased tone) from 207 +/- 29 mL (mean +/- SEM) during fasting to 106 +/- 14 mL postprandially (P = 0.01). With ondansetron, a tonic colonic response was induced postprandially (198 +/- 37 mL to 151 +/- 30 mL; P = 0.053). However, the increment in tone in the ondansetron group (23% +/- 7%) was significantly lower than in the placebo group (48% +/- 5%; P = 0.02) and was similar to that observed in untreated healthy subjects (24% +/- 3%). Postprandial manometric pressure activity increased significantly in the placebo group (P = 0.01); in the ondansetron group there was a trend (P = 0.09) to increased phasic activity.
  
  
  CONCLUSIONS
  Ondastetron reduces the postprandial colonic hypertonic response in carcinoid diarrhea to levels previously reported in health; further clinical studies of this class of antagonists in carcinoid diarrhea appear warranted.
authors.affiliation: Gastroenterology Research Unit, Mayo Clinic, Rochester, Minnesota.
authors.forename: M R
authors.initials: MR
authors.lastname: von der Ohe
authors.forename: M
authors.initials: M
authors.lastname: Camilleri
authors.forename: L K
authors.initials: LK
authors.lastname: Kvols
mesh_terms: D000328:Adult; D000368:Aged; D003106:Colon / Q000503:physiopathology*; D003967:Diarrhea / Q000188:drug therapy* / Q000503:physiopathology*; D004311:Double-Blind Method; D004435:Eating / Q000502:physiology*; D005215:Fasting / Q000502:physiology; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D017294:Ondansetron / Q000627:therapeutic use*; D012702:Serotonin Antagonists / Q000627:therapeutic use*
chemical_list: D012702:Serotonin Antagonists; D017294:Ondansetron