title: A ghrelin receptor agonist is an effective colokinetic in rats with diet-induced constipation.
abstract: BACKGROUND
  Despite constipation being a common problem, the treatments that are available have side effects and are only partly effective. Recent studies show that centrally penetrant ghrelin receptor agonists cause defecation in humans and other species. Here, we describe some features of a rat model of low fiber-induced constipation, and investigate the effectiveness of the ghrelin agonist, capromorelin.
  
  
  METHODS
  Rats were given low-fiber diets for 5 weeks. Their colorectal responsiveness to distension and to a behavioral test, water avoidance and colon histology were compared to those of rats on a standard diet.
  
  
  RESULTS
  After the low-fiber diet, distension of the colon produced fewer propulsive contractions, behaviorally induced defecation was reduced, and the lining of the colorectum was inflamed. However, capromorelin was similarly effective in causing defecation in constipated and non-constipated rats.
  
  
  CONCLUSIONS
  Low-fiber diet in rats produces a constipation phenotype, characterized by reduced responsiveness of the colorectum to distension and to a behavioral stimulus of defecation, water avoidance. The effectiveness of capromorelin suggests that centrally penetrant ghrelin receptor stimulants may be effective in treating constipation.
authors.affiliation: Department of Anatomy & Neuroscience, University of Melbourne, Parkville, VIC, Australia.
authors.forename: R V
authors.initials: RV
authors.lastname: Pustovit
authors.forename: J B
authors.initials: JB
authors.lastname: Furness
authors.forename: L R
authors.initials: LR
authors.lastname: Rivera
mesh_terms: D000818:Animals; D003106:Colon / Q000187:drug effects* / Q000473:pathology; D003248:Constipation; D003672:Defecation / Q000187:drug effects*; D004043:Dietary Fiber; D005769:Gastrointestinal Motility / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054440:Receptors, Ghrelin / Q000819:agonists*; D012007:Rectum / Q000187:drug effects* / Q000473:pathology
chemical_list: C433143:CP 424391; D004043:Dietary Fiber; D010880:Piperidines; D011720:Pyrazoles; D054440:Receptors, Ghrelin
keywords: capromorelin; constipation; ghrelin; low-fiber diet