title: Generation of Gastroesophageal Reflux Disease Symptoms During Esophageal Acid Infusion With Concomitant Esophageal pH Monitoring in Healthy Adults.
abstract: OBJECTIVE
  The sensitivity of the upper and lower esophageal mucosa to acid is considered to differ. We investigated the relationship between pH changes in different sites of the esophagus and generation of gastroesophageal reflux symptoms during an acid infusion test.
  
  
  METHODS
  An acid infusion catheter was placed at 5 or 15 cm above the lower esophageal sphincter (LES) in 18 healthy volunteers, while a 2-channel pH sensor catheter was also placed in each with the sensors set at 5 and 15 cm above the LES. Solutions containing water and hydrochloric acid at different concentrations were infused through the infusion catheter.
  
  
  RESULTS
  Acid infusion in the upper esophagus caused a pH drop in both upper and lower esophageal sites, whereas that in the lower esophagus resulted in a significant pH drop only in the lower without a corresponding pH decline in the upper esophagus. Stronger heartburn, chest pain, and chest oppression symptoms were noted when acid was infused in the upper as compared to the lower esophagus, while increased intra-esophageal acidity strengthened each symptom. Regurgitations caused by upper and lower esophageal acid infusions were similar, and not worsened by a larger drop in intra-esophageal pH. Chest pain was caused only by lowered intra-esophageal pH, while heartburn, chest oppression, and regurgitation were induced by a less acidic solution.
  
  
  CONCLUSIONS
  Higher intra-esophageal acidity caused stronger heartburn, chest pain, and chest oppression symptoms. However, regurgitation was not significantly influenced by intra-esophageal acidity. The upper esophagus showed higher acid sensitivity than the lower esophagus.
authors.affiliation: Department of Gastroenterology and Hepatology, Shimane University School of Medicine, Izumo, Japan. ; Division of Internal Medicine, Himeji Aiwa Hospital, Himeji, Japan.
authors.forename: Shunji
authors.initials: S
authors.lastname: Ohara
authors.forename: Kenji
authors.initials: K
authors.lastname: Furuta
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Adachi
authors.forename: Kousuke
authors.initials: K
authors.lastname: Fukazawa
authors.forename: Masahito
authors.initials: M
authors.lastname: Aimi
authors.forename: Masaharu
authors.initials: M
authors.lastname: Miki
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kinoshita
keywords: Esophagus; Gastroesophageal reflux; Heartburn