title: Effect of methylnaltrexone and naloxone on esophageal motor function in man.
abstract: BACKGROUND
  Endogenous opioids (EO) acting on μ-opiod receptors in central and enteric nervous system (ENS) control gastrointestinal motility but it is still unclear whether EO in ENS may control esophageal function in man, thus we will study the effects of methylnaltrexone (MNTX), a peripherally selective, and naloxone (NA), a non-selective μ-opiod receptor antagonist, on esophageal motility in healthy subjects.
  
  
  METHODS
  Fifteen HV (6 M; 34.1 ± 0.6 years; BMI: 22.1 ± 0.1 kg/m2) underwent three esophageal high-resolution manometry impedance (HRiM) studies with 10 saline swallows administered every 30 minutes: drug was administered after 30 minutes (MNTX subcutaneously/NA or saline intravenously), a solid meal after 90 minutes; measurements continued for 120 minutes postprandially.
  
  
  RESULTS
  Methylnaltrexone did not significantly decrease the upper esophageal sphincter (UES) percentage of relaxation preprandially (72.5 ± 5 vs 66.9 ± 4.6 and 73 ± 3.8%, ANOVA between placebo, MNTX and NA, P=NS) and postprandially (60 minutes: 68.2 ± 5.6 vs 61 ± 5.5 and 67.1 ± 5.6%; 120 minutes: 68 ± 5.9 vs 59.3 ± 5.2 and 67.7 ± 4.7%; ANOVA between placebo, MNTX and NA, P=NS). MNTX and NA did not significantly alter preprandial and postprandial LES resting pressures and integrated relaxation pressure (ANOVA between placebo, MNTX and NA, all P=NS). Peak front velocity and distal contractile integral were not altered pre- and postprandially by MNTX and NA (ANOVA between placebo, MNTX and NA, P=NS). Transient lower esophageal sphincter relaxations (TLESRs') number was not altered by MNTX and NA (ANOVA between placebo, MNTX and NA, all P=NS).
  
  
  CONCLUSIONS
  The peripheral selective and non-selective μ-opioid receptor antagonists MNTX and NA, respectively, do not alter TLESRs occurrence and esophageal peristalsis.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Scarpellini
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Pauwels
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Vos
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: Rommel
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Tack
mesh_terms: D000293:Adolescent; D000328:Adult; D018592:Cross-Over Studies; D049630:Esophageal Sphincter, Lower / Q000187:drug effects* / Q000502:physiology*; D050782:Esophageal pH Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors / Q000502:physiology; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D009292:Narcotic Antagonists; D000644:Quaternary Ammonium Compounds; D017450:Receptors, Opioid, mu; C032257:methylnaltrexone; D009270:Naloxone; D009271:Naltrexone
keywords: 
  GERD
  ; TLESRs; methylnaltrexone; naloxone; μ-opioid receptors