The effect of mechanoreceptor stimulation of the laryngopharynx on the oesophago-gastric junction

Stimulation of the pharynx by injection of minute amounts of water induces prolonged period of lower oesophageal sphincter (LOS) relaxation and augmen tation of the crural diaphragm (CD) contraction. The purpose of this study was to determine the effects of stimulating mechano-receptors at the laryng opharynx on the LOS and CD by using an air pulse stimulation device. Air pu lses were delivered via the internal channel of a flexible endoscope. Oesop hageal, LOS, and CD pressures; CD electromyogram; and oesophageal pH 5 cm a bove the LOS were recorded in nine healthy subjects. Stimulation of the lar yngopharynx induced LOS relaxation in the absence of swallow and oesophagea l peristalsis. The stimulation of epiglottis and arytenoid produced higher incidence of LOS relaxation compared to the base of tongue. The magnitude o f LOS relaxation differed significantly between the three anatomical sites, with greater relaxation occurring at the epiglottis and arytenoid compared with the base of the tongue. None of the LOS relaxations induced by laryng eal stimulation resulted in inhibition of the CD or gastroesophageal reflux . We conclude that stimulation of the laryngopharyngeal mechanoreceptors in duces LOS but not CD relaxation. The LOS relaxation induced by laryngophary ngeal stimulation is not accompanied by acid reflux in fasting state.