| 11875274 |
Welsh MJ, Smith JJ: cAMP stimulation of HCO3- secretion across airway epithelia. JOP. 2001 Jul;2(4 Suppl):291-3.
To test for the presence of HCO (3)(-) transport across airway epithelia, we measured short-circuit current in primary cultures of canine and human airway epithelia bathed in a Cl (-)-free, HCO (3)(-)/CO (2)-buffered solution. cAMP agonists stimulated a secretory current that was likely carried by HCO (3)(-) because it was absent in HCO (3)(-)-free solutions. In addition, the cAMP-stimulated current was inhibited by the carbonic anhydrase inhibitor, acetazolamide, and by the apical addition of a blocker of cystic fibrosis transmembrane conductance regulator (CFTR), diphenylamine-2-carboxylate. The current was dependent on Na (+) because it was inhibited by removing Na (+) from the submucosal solution and by inhibition of the Na (+)-K (+)-ATPase with ouabain. The cAMP-stimulated current was absent in cystic fibrosis (CF) airway epithelia. These data suggest that cAMP agonists can stimulate HCO (3)(-) secretion across airway epithelia and that CFTR may provide a conductive pathway for HCO (3)(-) movement across the apical membrane. |
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