title: Acid infusion into the esophagus increases the number of meal-induced transient lower esophageal sphincter relaxations (TLESRs) in healthy volunteers.
abstract: BACKGROUND
  Transient lower esophageal sphincter relaxation (TLESR) is the major mechanism of gastroesophageal reflux (GER) but the regulation of TLESR by stimuli in the esophagus is incompletely understood. If stimuli in the esophagus can influence TLESR, then such regulation may perpetuate or limit GER. We addressed the hypothesis that acid in the esophagus enhances TLESRs.
  
  
  METHODS
  We evaluated the effect of acid infusion into the distal esophagus on TLESRs evoked by a standard meal in a paired randomized study in healthy subjects. TLESRs were evaluated by using high resolution manometry (HRM).
  
  
  RESULTS
  We found that acid in the esophagus enhanced meal-induced TLESRs. Compared to control infusion the number of TLESRs (median [interquartile range]) was increased during 2 h following the acid infusion (11 [9-14] vs 17 [12.5-20], p < 0.01). The average duration of individual TLESRs was not affected. The time-course analysis revealed that a robust increase in TLESRs occurred already in the first hour when the number of TLESRs nearly doubled (6 [5.5-7.5] vs 11 [7.5-12.5], p < 0.05). In contrast to the enhancement of TLESRs, the number of swallows was not changed.
  
  
  CONCLUSIONS
  The acid infusion into the esophagus increases the number of meal-induced TLESRs in healthy subjects. Our results provide evidence for the concept that the stimuli in the esophagus can influence TLESRs. The regulation of TLESR by stimuli in the esophagus may contribute to pathogenesis of GER in some patients.
authors.affiliation: Department of Pathophysiology, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Bratislava, Slovakia.
authors.forename: J
authors.initials: J
authors.lastname: Halicka
authors.forename: P
authors.initials: P
authors.lastname: Banovcin
authors.forename: M
authors.initials: M
authors.lastname: Halickova
authors.forename: M
authors.initials: M
authors.lastname: Demeter
authors.forename: R
authors.initials: R
authors.lastname: Hyrdel
authors.forename: M
authors.initials: M
authors.lastname: Tatar
authors.forename: M
authors.initials: M
authors.lastname: Kollarik
mesh_terms: D000328:Adult; D003679:Deglutition; D004435:Eating; D049630:Esophageal Sphincter, Lower / Q000502:physiology*; D004947:Esophagus / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D005769:Gastrointestinal Motility / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry; D055815:Young Adult
keywords: acid; esophagus; gastroesophageal reflux; transient lower esophageal sphincter relaxation; vagus nerve