title: Modulation of the postprandial acid and bile pockets at the gastro-oesophageal junction by drugs that affect gastric motility.
abstract: BACKGROUND
  Previous studies have established the presence of a postprandial acid pocket at the gastro-oesophageal junction.
  
  
  OBJECTIVE
  To investigate whether altering gastric motility would affect the location and the extent of postprandial acid pockets in healthy volunteers and also to study the presence of bile in this pocket.
  
  
  METHODS
  A total of 16 healthy volunteers underwent pH and Bilitec probe stepwise pull-through to measure regional differences in pH and bile absorbance before and 10, 30 and 50 min after a liquid meal. At the start of the meal, saline, erythromycin or sumatriptan was administered.
  
  
  RESULTS
  After saline, ingestion of a meal induced an acid pocket, with a mean pH drop of 2.26 (compared to 0.25 before the meal, P < 0.05) and a nadir pH of 2.71. The acid pocket persisted 30 and 50 min postprandially (pH drops 1.59 and 1.68 and nadir pH 3.17 and 2.52 respectively). Compared with saline, erythromycin significantly suppressed the pH drop and nadir pH (on average 0.66 and 3.4 at 10 min; comparable patterns at 30 and 50 min). After sumatriptan a significantly lower nadir pH was observed at 30 and 50 min (respectively 2.02 and 1.74, P < 0.05 compared with saline). A postprandial bile pocket was noted in 50% of pull-throughs after saline, compared to 78% after erythromycin and 31% after sumatriptan.
  
  
  CONCLUSIONS
  The presence of a bile pocket in a subset of the subjects confirms the heterogeneity of postprandial intragastric contents. Erythromycin disrupts the acid pocket but increases the presence of bile, while sumatriptan has opposite effects.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, University of Leuven, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Boecxstaens
authors.forename: R
authors.initials: R
authors.lastname: Bisschops
authors.forename: K
authors.initials: K
authors.lastname: Blondeau
authors.forename: R
authors.initials: R
authors.lastname: Vos
authors.forename: E
authors.initials: E
authors.lastname: Scarpellini
authors.forename: D
authors.initials: D
authors.lastname: De Wulf
authors.forename: J
authors.initials: J
authors.lastname: Tack
mesh_terms: D000328:Adult; D001646:Bile / Q000187:drug effects* / Q000378:metabolism; D004917:Erythromycin / Q000008:administration & dosage*; D004943:Esophagogastric Junction / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D010919:Placebos / Q000008:administration & dosage*; D019518:Postprandial Period; D018170:Sumatriptan / Q000008:administration & dosage*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010919:Placebos; D004917:Erythromycin; D018170:Sumatriptan