title: The possible role of bicarbonate in mucosal protection and peptic ulceration.
abstract: The surface epithelial cells of the gastroduodenal mucosa are thought to be protected from the damaging effects of acid by a covering layer of mucus into which is secreted bicarbonate. It is proposed here that mucus acts as a true barrier to hydrogen ion diffusion, and that the role played by bicarbonate is to adjust mucus pH to a range at which this barrier property is optimized. It is further proposed that a high content of luminal bicarbonate will promote the transfer of protons across mucus by a buffer shuttle mechanism, and that this may be the basis for the development of peptic ulceration.
mesh_terms: D001639:Bicarbonates / Q000378:metabolism*; D002021:Buffers; D004381:Duodenal Ulcer / Q000209:etiology* / Q000378:metabolism; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000378:metabolism*; D009093:Mucus / Q000378:metabolism*; D013276:Stomach Ulcer / Q000209:etiology* / Q000378:metabolism
chemical_list: D001639:Bicarbonates; D002021:Buffers