title: The effects of methane and hydrogen gases produced by enteric bacteria on ileal motility and colonic transit time.
abstract: BACKGROUND
  Gases produced by intestinal flora may modulate intestinal motor function in healthy individuals as well as those with functional bowel disease. Methane, produced by enteric bacteria in the human gut, is associated with slowed intestinal transit and constipation. The effects of hydrogen, another main gas produced by bacterial fermentation in the gut, on small bowel and colonic motor function remains unrecognized. Therefore, we set out to investigate whether intestinal gases including methane and hydrogen could influence the small bowel motility and colonic transit.
  
  
  METHODS
  Guinea pig ileum was placed in the peristaltic bath with tension transducers attached to measure velocity and amplitude of peristaltic contraction before and after the infusion of control, hydrogen, and methane gases. Also, changes in the intraluminal pressures were monitored before and after the gas infusions.
  
  
  RESULTS
  Methane decreased peristaltic velocity and increased contraction amplitude significantly of guinea pig ileum (P < 0.05). The AUC of intraluminal pressure was significantly increased with methane in guinea pig ileum (P < 0.05). In a second experiment, guinea pig colon was placed in the peristaltic bath to measure transit time before and after control, hydrogen, methane, and methane-hydrogen mixture gas infusions. Hydrogen shortened colonic transit time by 47% in the proximal colon, and by 10% in the distal colon, when compared with baselines (P < 0.05).
  
  
  CONCLUSIONS
  Methane delayed ileal peristaltic conduction velocity by augmenting contractility. Hydrogen shortened colonic transit, and that effect was more prominent in the proximal colon than distal colon.
authors.affiliation: Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Jahng
authors.forename: I S
authors.initials: IS
authors.lastname: Jung
authors.forename: E J
authors.initials: EJ
authors.lastname: Choi
authors.forename: J L
authors.initials: JL
authors.lastname: Conklin
authors.forename: H
authors.initials: H
authors.lastname: Park
mesh_terms: D000818:Animals; D003106:Colon / Q000187:drug effects* / Q000503:physiopathology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000503:physiopathology; D005772:Gastrointestinal Transit / Q000187:drug effects*; D006168:Guinea Pigs; D006859:Hydrogen / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008697:Methane / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects
chemical_list: D006859:Hydrogen; D008697:Methane