Effect of baclofen on the acid pocket at the gastroesophageal junction.
Previous studies established that a pocket of highly acidic gastric juice is present postprandially at the gastroesophageal junction in man. The GABA-B agonist baclofen inhibits postprandial reflux events through its effects on the lower esophageal sphincter (LES). The aim of the current study was to investigate whether baclofen would affect the location and the extent of the postprandial acid pocket in healthy volunteers. Twelve healthy volunteers underwent acid pocket studies on two different occasions, at least 1 week apart. LES position was determined preprandially with pull-through manometry. Dual pH electrode and manometry probe stepwise pull-through (1 cm/minute, LES-10 to +5 cm) was performed at 30-minute intervals for 150 minutes, with administration of placebo or baclofen 40 mg after the first and ingestion of a liquid meal after the second pull-through. After placebo, a significant drop in intragastric gastric pH was present at the gastroesophageal junction after the meal, reflecting the acid pocket, and this was associated with a drop in LES pressure. Baclofen did not affect the presence of the acid pocket, but prevented the postprandial drop in LES pressure, and the extent of the acid pocket above the upper margin of the manometrically located LES was significantly decreased by baclofen (1.6 ± 0.7 vs. 0.3 ± 0.4 cm at 60 minutes, 2.2 ± 0.6 vs. 0.2 ± 0.6 at 90 minutes, and 1.5 ± 0.5 vs. 0.7 ± 0.7 cm at 120 minutes, all P < 0.05). Baclofen does not alter the intragastric acid pocket, but limits its extension into the distal esophagus, probably through an increase in postprandial LES pressure.
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Scarpellini
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Boecxstaens
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Farré
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Bisschops
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Dewulf
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Gasbarrini
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Pauwels
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Blondeau
Department of Internal Medicine, Division of Gastroenterology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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Tack
D000328:Adult; D001418:Baclofen / Q000494:pharmacology*; D049630:Esophageal Sphincter, Lower / Q000187:drug effects* / Q000502:physiology; D004943:Esophagogastric Junction / Q000033:anatomy & histology / Q000187:drug effects*; D005260:Female; D058786:GABA-B Receptor Agonists / Q000494:pharmacology*; D005750:Gastric Juice; D005764:Gastroesophageal Reflux / Q000188:drug therapy / Q000517:prevention & control; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods; D019518:Postprandial Period / Q000187:drug effects / Q000502:physiology; D011312:Pressure; D055815:Young Adult
D058786:GABA-B Receptor Agonists; D001418:Baclofen
GABA-B receptor; acid pocket; baclofen; gastroesophageal reflux disease