title: Effect of topical oesophageal acidification on human salivary and oesophageal alkali secretion.
abstract: Recent human studies suggest that oesophageal HCO3- secretion, in conjunction with salivary HCO3- secretion and secondary oesophageal peristalsis, is important for the protection of oesophageal mucosa from refluxed gastric contents. This study evaluated simultaneously the responsiveness of oesophageal and salivary HCO3- secretion to oesophageal acidification in eight healthy subjects. A 10 cm segment of oesophagus was perfused at a constant rate of 5 ml/min with a specially designed tube assembly. Saline was used initially, and then 10 mM and 100 mM HCl. The perfusates contained 3H-polyethylene glycol (PEG) as a concentration marker to determine volumes. Corrections were applied for a small degree of contamination by swallowed saliva and refluxed gastric alkali. Oesophageal perfusion with 10 mM HCl did not cause symptoms (nausea and heartburn), but tripled the oesophageal HCO3- output from a baseline of 51 mumol/10 cm/10 min (p = 0.021), while doubling the rate of salivary HCO3- secretion from a median basal value of 140 mumol/10 min (p = 0.021). Oesophageal perfusion with 100 mM HCl was associated with symptoms of nausea and heartburn in all subjects. The median oesophageal HCO3- output increased 32 fold to 1659 mumol/10 cm/10 min (interquartile range 569 to 3373; p = 0.036), and salivary HCO3- secretion approximately tripled from basal values (p = 0.036). In conclusion, oesophageal acidification stimulates both salivary and oesophageal HCO3- secretion, responses which may be protective to the oesophageal epithelium.
authors.affiliation: Department of Gastroenterology, Hope Hospital, University of Manchester, School of Medicine, Salford.
authors.forename: C M
authors.initials: CM
authors.lastname: Brown
authors.forename: C F
authors.initials: CF
authors.lastname: Snowdon
authors.forename: B
authors.initials: B
authors.lastname: Slee
authors.forename: L N
authors.initials: LN
authors.lastname: Sandle
authors.forename: W D
authors.initials: WD
authors.lastname: Rees
mesh_terms: D000287:Administration, Topical; D000328:Adult; D001639:Bicarbonates / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004947:Esophagus / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006356:Heartburn / Q000139:chemically induced; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D009325:Nausea / Q000139:chemically induced; D012463:Saliva / Q000378:metabolism*; D013268:Stimulation, Chemical
chemical_list: D001639:Bicarbonates; D006851:Hydrochloric Acid