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Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin

Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic digestion. In this article we review the present state of the gastroduodenal mucus bicarbonate barrier two decades after the first supporting experimental evidence appeared. The primary function of the adherent mucus gel layer is a structural one to create a stable, unstirred layer to support surface neutralization of acid and act as a protective physical barrier against luminal pepsin. Therefore, the emphasis on mucus in this review is on the form and role of the adherent mucus gel layer. The primary function of the mucosal bicarbonate secretion is to neutralize acid diffusing into the mucus gel layer and to be quantitatively sufficient to maintain a near-neutral pH at the mucus-mucosal surface interface. The emphasis on mucosal bicarbonate in this review is on the mechanisms and control of its secretion and the establishment of a surface pH gradient. Evidence suggests that under normal physiological conditions, the mucus bicarbonate barrier is sufficient for protection of the gastric mucosa against acid and pepsin and is even more so for the duodenum. acid-base transporters; cystic fibrosis transmembrane conductance regulator channel; surface pH gradient; mucus gels; trefoil peptides Address for reprint requests and other correspondence: G. Flemström, Division of Physiology, Dept. of Neuroscience, Uppsala Univ., BMC, PO Box 572, SE-751 23 Uppsala, Sweden (E-mail: [email protected] ) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Cell Physiology The American Physiological Society

Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin

Allen, Adrian; Flemström, Gunnar
AJP - Cell Physiology , Volume 288 (1): C1 – Jan 1, 2005
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References (283)

Publisher
The American Physiological Society
Copyright
Copyright © 2010 the American Physiological Society
ISSN
0363-6143
eISSN
1522-1563
DOI
10.1152/ajpcell.00102.2004
pmid
15591243
Publisher site
See Article on Publisher Site

Abstract

Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic digestion. In this article we review the present state of the gastroduodenal mucus bicarbonate barrier two decades after the first supporting experimental evidence appeared. The primary function of the adherent mucus gel layer is a structural one to create a stable, unstirred layer to support surface neutralization of acid and act as a protective physical barrier against luminal pepsin. Therefore, the emphasis on mucus in this review is on the form and role of the adherent mucus gel layer. The primary function of the mucosal bicarbonate secretion is to neutralize acid diffusing into the mucus gel layer and to be quantitatively sufficient to maintain a near-neutral pH at the mucus-mucosal surface interface. The emphasis on mucosal bicarbonate in this review is on the mechanisms and control of its secretion and the establishment of a surface pH gradient. Evidence suggests that under normal physiological conditions, the mucus bicarbonate barrier is sufficient for protection of the gastric mucosa against acid and pepsin and is even more so for the duodenum. acid-base transporters; cystic fibrosis transmembrane conductance regulator channel; surface pH gradient; mucus gels; trefoil peptides Address for reprint requests and other correspondence: G. Flemström, Division of Physiology, Dept. of Neuroscience, Uppsala Univ., BMC, PO Box 572, SE-751 23 Uppsala, Sweden (E-mail: [email protected] )

Journal

AJP - Cell Physiology – The American Physiological Society

Published: Jan 1, 2005

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