Activation of esophageal mechanoreceptors alters the pharyngeal phase of swallow

Abstract

The effects of esophageal mechanoreceptors on the pharyngeal phase of swallow have not been determined. We hypothesized that rapid activation of esophageal mechanoreceptors would increase swallow excitability to ensure successful movement of the bolus from the pharynx into the esophagus. Electromyograms of the mylohyoid, geniohyoid, thyrohyoid, thyroarytenoid, thyropharyngeus, cricopharyngeus and costal diaphragm were recorded in 8 spontaneously breathing cats. Swallow was elicited by infusion of water into the oropharynx and mechanoreceptor activation was produced by distension of a balloon in the upper third of the esophagus. Esophageal distension alone produced swallows in all animals in at least 1 trial. Trials in which the esophagus was distended while water was infused in the mouth had increased swallow‐related EMG recruitment of all recorded muscles compared to swallows produced by distension alone (p<.05). Water alone increased swallow‐related EMG recruitment on supra‐hyoid muscles (mylohyoid and geniohyoid) compared to esophageal distension alone (p<.05). Swallow duration was unchanged across all conditions. These results support a theory of esophageal afferent feedback modifying the excitability of the pharyngeal phase of swallow, and could be a novel therapeutic target in patients with dysphagia.Support or Funding InformationSupported by R00‐HL111215, the Kentucky Spinal Cord and Head injury Trust, and The Commonwealth of Kentucky Challenge for Excellence.