title: Control of esophageal distension-induced secondary peristalsis by the GABA(B) agonist baclofen in humans.
abstract: BACKGROUND
  Secondary peristalsis is important for the clearance of retained food bolus or refluxate from the esophagus. The effects of the gamma aminobutyric acid receptor type B (GABA(B) ) agonist on secondary peristalsis remain unclear in humans. We aimed to investigate the effect of a GABA(B) agonist baclofen on esophageal secondary peristalsis.
  
  
  METHODS
  After a baseline recording of esophageal motility, secondary peristalsis was generated by slow and rapid mid-esophageal injections of air in 15 healthy subjects. Two separate sessions with 40mg oral baclofen or placebo were randomly performed to test their effects on secondary peristalsis.
  
  
  RESULTS
  Baclofen increased the threshold volume for triggering secondary peristalsis during slow air distension (P=0.003) and rapid air distension (P=0.002). Baclofen reduced the rate of secondary peristalsis by rapid air distension from 90% to 30% (P=0.0002). Baclofen increased basal lower esophageal sphincter pressure (P=0.03). Baclofen did not affect any of peristaltic parameters during primary or secondary peristalsis.
  
  
  CONCLUSIONS
  This study provides an evidence for inhibitory modulation of esophageal secondary peristalsis by the GABA(B) agonist baclofen. Activation of secondary peristalsis is probably modulated by GABA(B) receptors; however, baclofen does not lead to any motility change in secondary peristalsis.
authors.affiliation: Department of Medicine, Buddhist Tzu Chi General Hospital and Tzu Chi University, Hualien, Taiwan. harry.clchen@msa.hinet.net
authors.forename: C L
authors.initials: CL
authors.lastname: Chen
authors.forename: T T
authors.initials: TT
authors.lastname: Liu
authors.forename: C H
authors.initials: CH
authors.lastname: Yi
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001418:Baclofen / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004947:Esophagus / Q000187:drug effects* / Q000502:physiology; D005260:Female; D058786:GABA-B Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008365:Manometry; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D010528:Peristalsis / Q000187:drug effects* / Q000502:physiology; D018080:Receptors, GABA-B / Q000187:drug effects / Q000502:physiology
chemical_list: D058786:GABA-B Receptor Agonists; D018080:Receptors, GABA-B; D001418:Baclofen