Differential effects of baclofen on lower oesophageal sphincter pressure and proximal gastric motility in humans.
BACKGROUND
The gamma-aminobutyric acid receptor type B agonist, baclofen, inhibits transient lower oesophageal sphincter relaxations by influencing a vagal pathway. Although post-prandial proximal gastric function, which is vagally mediated, is important in the occurrence of transient lower oesophageal sphincter relaxations, the effects of baclofen on post-prandial proximal gastric motility in humans remains undetermined.


OBJECTIVE
To determine the effects of baclofen on post-prandial lower oesophageal sphincter function and proximal gastric motility in healthy subjects.


METHODS
In 11 healthy volunteers, a barostat bag and an oesophageal manometric catheter with a sleeve were simultaneously positioned; 40 mg of oral baclofen or placebo was then given in a randomized, double-blind manner. Subsequently, the intragastric bag volume, oesophageal and lower oesophageal sphincter pressure and oesophageal pH were recorded during the 90 min before and 120 min after a meal.


RESULTS
During the post-prandial period, unlike the fasting period, baclofen decreased the rate of transient lower oesophageal sphincter relaxations and increased the basal lower oesophageal sphincter pressure compared with placebo. However, the meal-induced decrease in the tone and phasic contractility of the fundus was not affected by baclofen.


CONCLUSIONS
The gamma-aminobutyric acid receptor type B agonist, baclofen, has a potent effect on post-prandial lower oesophageal sphincter motility without altering post-prandial proximal gastric motility, suggesting differential effects of baclofen on different signals of gastrointestinal vagal afferents.
Lee
K-J
KJ
Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, University of Leuven, Belgium.
Vos
R
R
Janssens
J
J
Tack
J
J
D000328:Adult; D001418:Baclofen / Q000494:pharmacology*; D004311:Double-Blind Method; D004943:Esophagogastric Junction / Q000187:drug effects*; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D005748:Gastric Fundus / Q000187:drug effects; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D011312:Pressure
D018755:GABA Agonists; D009125:Muscle Relaxants, Central; D001418:Baclofen