Preservation of lower esophageal sphincter asymmetry after acid-induced abolition of the high pressure zone.

Over a decade ago acid abolition of the esophageal high-pressure zone in the cat was described. This finding was inconsistent with other studies demonstrating that the esophagus was impermeable to acid. Because this finding had been used to support the hypothesis of a "vicious circle" in the course of esophagitis, this phenomenon was re-studied in the cat. In ten animals, acid irrigation of the esophagus caused both esophagitis and transient reduction in lower esophageal sphincter (LES) manometric pressures. Despite the reduction in pressures, manometric asymmetry of the LES was preserved and the esophagitis promptly resolved when acid irrigation was stopped. We therefore conclude that although LES pressure may be abolished, this alone is insufficient to produce reflux and esophagitis over the long term. Preservation of asymmetry implies that the multiple exogenous components composing the LES may not be damaged by this insult.