References
Query Results -- Details
MGI Accession ID: MGI:1354048
J Number: J:60880
Other Accession IDs:
Title: Acid-base effects on electrolyte transport in CA II-deficient mouse colon.
Authors: Goldfarb DS; Sly WS; Waheed A; Charney AN
Journal: Am J Physiol Gastrointest Liver Physiol
Volume: 278
Issue: 3
Date: 2000 Mar
Year: 2000
Pages: G409-15
Review Status: Peer Reviewed
Abstract:
To determine the role of carbonic anhydrase (CA) in colonic electrolyte transport, we studied Car-2(0) mice, mutants deficient in cytosolic CA II. Ion fluxes were measured under short-circuit conditions in an Ussing chamber. CA was analyzed by assay and Western blots. In Car-2(0) mouse colonic mucosa, total CA activity was reduced 80% and cytosolic CA I and membrane-bound CA IV activities were not increased. Western blots confirmed the absence of CA II in Car-2(0) mice. Normal mouse distal colon exhibited net Na(+) and Cl(-) absorption, a serosa-positive PD, and was specifically sensitive to pH. Decrease in pH stimulated active Na(+) and Cl(-) absorption whether it was caused by increasing solution PCO(2), reducing HCO(-)(3) concentration, or reducing pH in CO(2)/HCO(-)(3)-free HEPES-Ringer solution. Membrane-permeant methazolamide, but not impermeant benzolamide, at 0.1 mM prevented the effects of pH. Car-2(0) mice exhibited similar basal transport rates and responses to pH and CA inhibitors. We conclude that basal and pH-stimulated colonic electrolyte absorption in mice requires CA I. CA II and IV may have accessory roles.
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