Advertisement

Bicarbonate Secretion and the Alkaline Microclimate

  • Christopher J. Shorrock
  • Wynne D. W. Rees

Abstract

The surface mucosa of the healthy stomach and duodenum is continually exposed to a corrosive mixture of hydrochloric acid, pepsin, transient reflux of bile (exposing the stomach to the detergent effects of bile salts), food with varied consistency and temperature, microorganisms, and in some instances alcohol and drugs. In the duodenum, acid emptying from the stomach is rapidly neutralized, but pH values of ∼2 may still occur in the proximal duodenum for variable lengths of time. Clearly, these aggressive damaging luminal factors, along with ingested agents such as nonsteroidal anti-inflammatory drugs (NSAID) and alcohol, must be balanced by defense and repair processes, if mucosal integrity is to be maintained.

Keywords

Gastric Inhibitory Polypeptide Mucosal Blood Flow Bicarbonate Secretion Proximal Duodenum Gastroduodenal Mucosa 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Annotated Bibliography

  1. Bickel M, Kaufman G: Gastric mucus gel thickness: Effect of distension, 16,16-dimethylprostaglan-din E2 and carbenoxolone. Gastroenterology 80:770–775, 1981. Method for measuring mucus gel thickness and the effects of various agents on this thickness.PubMedGoogle Scholar
  2. Flemstrom G: Gastric and duodenal mucosal bicarbonate secretion, in Johnson RL, Christensen J, Jacobson E, Jackson MJ, Walsh JH (eds): Physiology of the GI tract, ed. 2. Vol. 2. New York, Raven, 1986. pp. 1011–1029. Thorough discussion of physiology and measurement of mucosal bicarbonate secretion.Google Scholar
  3. Flemstrom G, Kivilaakso E: Demonstration of a pH gradient at the luminal surface of rat duodenum in vivo and its dependence on mucosal alkaline secretion. Gastroenterology 84:787–794, 1983. Important paper demonstrating duodenal pH gradient in vivo.PubMedGoogle Scholar
  4. Heatley NG: Mucosubstance and a barrier to diffusion. Gastroenterology 37:313–317, 1959. Classic paper predicting the presence of the mucus-bicarbonate barrier.PubMedGoogle Scholar
  5. Heylings JR, Garner A, Flemstrom G: Regulation of gastroduodenal bicarbonate transport by luminal acid in the frog in vitro. Am J Physiol 246:G235–242, 1984. Important paper introducing the concept of autoregulation of bicarbonate secretion.PubMedGoogle Scholar
  6. Isenberg JI, Hogan DL, Koss MA, et al: Human duodenal mucosal bicarbonate secretion. Evidence for basal secretion and stimulation by hydrochloric acid and a synthetic prostaglandin El analogue. Gastroenterology 91:370–378, 1986. Shows method for measuring human duodenal bicarbonate secretion.PubMedGoogle Scholar
  7. Quigley EMM, Turnberg LA: The pH of the microclimate lining human gastric and duodenal mucosa in vivo: Studies in control subjects and in duodenal ulcer patients. Gastroenterology 92:1876–1884, 1987. Shows method used for measuring pH gradient in human gastric and duodenal mucosa.PubMedGoogle Scholar
  8. Rees WDW, Botham D, Turnberg LA: A demonstration of bicarbonate production by the normal human stomach in vivo. Dig Dis Sci 27:961–966, 1982. Important paper showing method for measuring human gastric bicarbonate secretion.PubMedCrossRefGoogle Scholar
  9. Rees WDW, Gibbons LC, Warhurst G, et al: Studies of bicarbonate secretion in the normal human stomach in vivo: Effect of aspirin, sodium taurocholate, and prostaglandin E2, in Allen A, Flemstrom G, Garner A, Silen W, Turnberg, LA (eds): Mechanisms of Mucosal Protection in the Upper Gastrointestinal Tract. New York, Raven, 1984, p. 119–123. Shows effect of various damaging and protective agents on human gastric bicarbonate secretion.Google Scholar
  10. Ross IN, Bahari HMM, Turnberg LA: The pH gradient across mucus adherent to rat fundic mucosa in vivo and the effects of possible damaging agents. Gastroenterology 81:713–718, 1981. Important paper showing measurement of pH gradient across gastric mucus gel and the effect of damaging agents.PubMedGoogle Scholar
  11. Schierbeck NP: Ueber Kohlemsaure im Ventrikel. Scand Arch Physiol 8:437–474, 1892. Classic work of historical interest.Google Scholar
  12. Wallace JL, Whittle BJR: Role of mucus in the repair of gastric epithelial damage in the rat. Gastroenterology 91:603–611, 1986. Important paper discussing the importance of the mucus cap.PubMedGoogle Scholar

Copyright information

© Plenum Publishing Corporation 1989

Authors and Affiliations

  • Christopher J. Shorrock
    • 1
  • Wynne D. W. Rees
    • 1
  1. 1.Department of Gastroenterology, Hope HospitalUniversity of Manchester School of MedicineSalfordEngland

Personalised recommendations