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Duodenal Chemosensing and Mucosal Defenses
- Source :
- Digestion. 83:25-31
- Publication Year :
- 2011
- Publisher :
- S. Karger AG, 2011.
-
Abstract
- The duodenal mucosa is exposed to endogenous and exogenous chemicals, including acid, CO2, bile acids and nutrients. Mucosal chemical sensors are necessary to exert physiological responses such as secretion, digestion, absorption, and motility. We propose a mucosal chemosensing system by which luminal chemicals are sensed via mucosal acid sensors and G-protein-coupled receptors. Luminal acid/CO2 sensing consists of ecto- and cytosolic carbonic anhydrases, epithelial ion transporters, and acid sensors expressed on the afferent nerves in the duodenum. Furthermore, a luminal L-glutamate signal is mediated via mucosal L-glutamate receptors, including metabotropic glutamate receptors and taste receptor 1 family heterodimers, with activation of afferent nerves and cyclooxygenase, whereas luminal Ca2+ is differently sensed via the calcium-sensing receptor in the duodenum. Recent studies also show the involvement of enteroendocrine G-protein-coupled receptors in bile acid and fatty acid sensing in the duodenum. These luminal chemosensors help activate mucosal defense mechanisms in or- der to maintain the mucosal integrity and physiological responses. Stimulation of luminal chemosensing in the duodenal mucosa may prevent mucosal injury, affect nutrient metabolism, and modulate sensory nerve activity.
- Subjects :
- Paper
Duodenum
Extramural
Gastroenterology
Carbon Dioxide
Hydrogen-Ion Concentration
Pharmacology
Chemoreceptor Cells
Physiological responses
Receptors, G-Protein-Coupled
Gastric Acid
Bicarbonates
Esophagus
Biochemistry
Receptors, Purinergic P2Y
Humans
Duodenal mucosa
Amino Acids
Intestinal Mucosa
Receptors, Calcium-Sensing
Subjects
Details
- ISSN :
- 14219867 and 00122823
- Volume :
- 83
- Database :
- OpenAIRE
- Journal :
- Digestion
- Accession number :
- edsair.doi.dedup.....d6a9029dbb143243d3034b083f8909dd