Influence of intraluminal acidification on esophageal secondary peristalsis in humans

Secondary peristalsis contributes to clearance of retained refluxate or material from the esophagus.

The goal of our study was to investigate the effects of hydrochloric acid (HCl) on physiological characteristics of esophageal secondary peristalsis in healthy adults.

After recording esophageal motility baseline for primary peristalsis, secondary peristalsis was stimulated with slow and rapid air injections in the mid-esophageal in 16 healthy subjects. Normal saline and HCl (0.1 N) were separately infused into the esophagus to test whether they had effects on secondary peristalsis.

After infusion of HCl, the threshold volume to generate secondary peristalsis was significantly decreased during rapid and slow air infusions (both P < 0.05). The frequency of secondary peristalsis was increased after HCl infusion (90 % [72.5-100 %] versus 85 % [72.5-90 %], P = 0.002). Infusion of HCl significantly increased pressure wave amplitude during rapid and slow air infusions (both P < 0.05). Infusion of saline did not affect any parameters of secondary peristalsis. The occurrence of heartburn was generated in 7 of 16 subjects after infusion of HCl with an increase in visual analogue scale score (12.5).

Our data show that acute esophageal acid infusion enhances sensitivity of distension-induced secondary peristalsis and enhances secondary peristaltic activity. The study supports the evidence of the presence of acid-sensitive afferents in the modulation of distension-induced secondary peristalsis in humans.