| First Author | Chen M | Year | 2012 |
| Journal | J Physiol | Volume | 590 |
| Issue | 14 | Pages | 3317-33 |
| PubMed ID | 22586225 | Mgi Jnum | J:200059 |
| Mgi Id | MGI:5506872 | Doi | 10.1113/jphysiol.2011.226506 |
| Citation | Chen M, et al. (2012) The electroneutral Na(+):HCO(3)(-) cotransporter NBCn1 is a major pHi regulator in murine duodenum. J Physiol 590(Pt 14):3317-33 |
| abstractText | Duodenocyte pHi control and HCO3 - secretion protects the proximal duodenum against damage by gastric acid. The molecular details of duodenocyte pH control are not well understood. A selective duodenal expression (within the upper GI tract) has been reported for the electroneutral Na+:HCO3 - cotransporter NBCn1 (Slc4a7). We aimed to determine the role of NBCn1 and NBCe2 in duodenocyte intracellular pH regulation as well as basal and agonist-stimulated duodenal bicarbonate secretion (JHCO3 -), exploiting mouse models of genetic slc4a7 and slc4a5 disruption. Basal and forskolin (FSK)-stimulated JHCO3 - was measured by single-pass perfusion in the duodenum of slc4a7-/- and slc4a7+/+ as well as slc4a5-/- and slc4a5+/+ mice in vivo, and by pH-stat titration in isolated duodenal mucosa in vitro. Duodenocyte HCO3 - uptake rates were fluorometrically assessed after acidification of intact villi and of isolated duodenocytes. Slc4a7-/- mice displayed significantly lower basal and FSK-stimulated duodenal HCO3 - secretion than slc4a7+/+ littermates in vivo. FSK-stimulated HCO3 - secretion was significantly reduced in slc4a7-/- isolated duodenal mucosa. Na+- and HCO3 --dependent base uptake rates were significantly decreased in slc4a7-/- compared with slc4a7+/+ villus duodenocytes when measured in intact villi. Carbonic anhydrase (CA)-mediated CO2 hydration played no apparent role as a HCO3 |
