An experimental model for the study of transient lower oesophageal sphincter relaxation and motor function of the proximal stomach in humans.

A simple and reliable experimental model would be useful in human research on new drugs which target transient lower oesophageal sphincter (LOS) relaxation. The aim was to investigate the effect of repeated distensions on the rate of transient LOS relaxation, LOS pressure and motor function of the proximal stomach. Twelve healthy subjects were studied with a multilumen manometric assembly incorporating a sleeve sensor for the LOS and a bag positioned in the proximal stomach and connected to a barostat. Intrabag volume was set at 75% of the threshold for gastric discomfort and maintained for two 30-min distension periods separated by a 45-min washout with the bag deflated. The studies lasted 145 +/- 2 min. The rate of transient LOS relaxations was similar during the two distensions, 3.5;2-4 vs 3;2.5-4 (median;interquartile range) and so was LOS pressure. Baseline intrabag pressure, as a measure of gastric tone, and the number of pressure waves, as a measure of phasic contractions, were also similar, 11.3;9.3-12.3 mmHg vs 10.8;9.3-12.5 mmHg and 16;13-28 mmHg vs 19;15-29 mmHg, respectively. Our model allows to perform 1-day studies which can assess two experimental conditions on transient LOS relaxations and motor function of the proximal stomach within an acceptable time span.