RESPONSES OF THE HUMAN ESOPHAGUS TO EXPERIMENTAL INTRALUMINAL DISTENSION

Contractile and propulsive forces generated in response to intraluminal distension of the human esophagus were measured in 30 volunteers with the use of a novel intraluminal catheter assembly. Distension was achieved by graded inflation of a balloon for periods of 30 s using volumes of air varying between 0 and 12 ml. In the lower esophagus, distension above a threshold volume of 5 (3-10) ml (median and interquartile range) induced a traction force together with contractile activity proximal to the balloon and quiescence distally. Proximal contractile activity and aboral traction force increased with increasing inflation volume, the magnitude of the response being additionally dependent on the site and the length of esophageal wall stimulated. Although the threshold for induction of motor responses was similar at different distension sites, the magnitude of both contractile and traction responses was higher in the distal than in the midesophagus. In the upper esophagus, the contractions induced proximal to the distension propagated aborally, whereas in the lower esophagus nonpropagating proximal contractions were induced. With the use of a dual balloon technique, it was possible to demonstrate that the distal quiescence represented a true descending inhibitory response since inflation of a proximal balloon suppressed the contractile response induced by a distal balloon. These results thus provide a description of the human esophageal response to distension against which responses in disease states can be compared.