On the relationship between gastric pH and pressure in the normal human lower oesophageal sphincter.

The effect upon the lower oesophageal sphincter (LOS) of acid in the proximal stomach was investigated in 12 young healthy subjects. The cardia was perfused in turn with solutions at pH 7, 4, 3, 2, and 1, during successive withdrawals of three perfused pressure-recording catheters, openings of which were at the same axial level. Although there was considerable individual variation, there was a direct and significant relationship between LOW pressure and the acidity of the solution perfused. The results suggest that resting LOS pressure and the acidity of the solution perfused. The results suggest that resting LOS pressure may be determined in part by the pH of the gastric content.