INHIBITION OF PROGRESSING PRIMARY ESOPHAGEAL PERISTALSIS BY PHARYNGEAL WATER STIMULATION IN HUMANS

Background and Aims: Sensory impulses initiated from the pharynx exert differing effects on the deglutitive apparatus, They have an inhibito ry effect on the lower esophageal sphincter but an excitatory effect o n the upper esophageal sphincter, The aim of this study was to systema tically investigate the effect of pharyngeal sensory impulses evoked b y water stimulation on the progressing esophageal peristalsis, Methods : Sixteen healthy young volunteers were studied in the supine position . The presence of normal peristalsis was verified, Esophageal peristal sis was recorded 3, 6, 9, 12, 15, and 18 cm above the lower esophageal sphincter, Pharyngeal stimulation was performed by injecting a predet ermined threshold volume into the pharynx 2 cm above the upper esophag eal sphincter, directed posteriorly. The injections were timed to coin cide with the arrival of the peristaltic wave induced by dry swallows at respective recording sites, Results: Injection of the threshold vol ume (0.5 +/- 0.1 mL) stopped the progression of peristalsis at both th e striated and smooth muscle esophagus, Topical pharyngeal anesthesia blocked this inhibitory effect (P < 0.01), Conclusions: Sensory impuls es initiated from the pharynx evoked by water injection inhibit the pr ogression of primary esophageal peristalsis. Although the clinical sig nificance of these findings is not determined, they may explain the me chanism of some of the failed esophageal peristalsis.