Alteration of swallowing and oesophageal peristalsis by different initiators of deglutition.

It has long been believed that once initiated, the involuntary phase of deglutition follows a stereotypical pattern, that is modified only by ongoing sensory input from the transported bolus. To test the hypothesis that the mode of sensory activation of deglutition can modify the motor response irrespective of bolus characteristics, the mylohyoid, lower oesophageal sphincter (LES) and oesophageal body response to swallows induced in anaesthetized opossums by pharyngeal stroking or superior laryngeal nerve (SLN) stimulation (unilateral and bilateral) were compared. In comparison with unilateral SLN stimulation, swallows triggered by pharyngeal stroking resulted in a greater mylohyoid spike burst and LES relaxation. There was no significant difference in the oesophageal and LES motor response to pharyngeal stroking vs bilateral SLN stimulation, although the mylohyoid response was of greater magnitude with pharyngeal stroking. These studies demonstrate that the motor component of deglutition can be altered by different sensory initiators of swallowing, and provides a possible link between oropharyngeal and oesophageal motor disorders.