TRANSIENT LOWER ESOPHAGEAL SPHINCTER RELAXATIONS AND ESOPHAGEAL BODY MUSCULAR CONTRACTILE RESPONSE IN NORMAL HUMANS

Background & Aims: Gastroesophageal reflux frequently occurs during sp ontaneous transient lower esophageal sphincter relaxations (TLESRs). T he aim of this study was to determine the motor activity in the body o f the esophagus during TLESRs in 10 healthy subjects. Methods: Esophag eal contractions were recorded 13, 8, and 3 cm above a sleeve that mea sured LES pressure. A balloon was inflated 8 cm above the sleeve to in duce an esophageal tonic contraction (artificial high-pressure zone). Results: No relaxation of the artificial high-pressure zone was detect ed at the onset or during spontaneous TLESRs before gastroesophageal r eflux. Esophageal acidification provoked no changes or increased the p ressure in the artificial high-pressure zone by 47.9% +/- 12%. When ga stroesophageal reflux abruptly distended the esophagus (common cavity) , a relaxation of the artificial high-pressure zone of 51.1% +/- 6.6% was observed in 78% of the instances. Deglutitive or secondary contrac tions during spontaneous TLESRs traveled down the esophagus in 96.5% o f the instances. Conclusions: Stimuli that induced spontaneous TLESRs did not by themselves inhibit muscle contractility in the body of the esophagus. Acidification without distention of the lower esophagus fre quently increased esophageal tonic contractility. Abrupt lower esophag eal distention by reflux of air or acid partially relaxed the artifici al high-pressure zone in the esophageal body, probably to assist gastr ic venting.