Anion interactions with CFTR and consequences for HCO3 transport in secretory epithelia

M. A. Gray, C. O'Reilly, J. P. Winpenny, B. Argent

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We have been studying CFTR channels in guinea pig pancreatic duct cells and rather surprisingly found that luminal HCO3- had a pronounced inhibitory effect on cAMP-activated CFTR chloride currents. The block produced by HCO3- was rapid, voltage-independent and occurred over a physiological range of extracellular HCO3-concentrations. I- and ClO4- were also found to inhibit CFTR currents, but both were less effective than HCO3-. Although we have not identified how HCO3-is able to block CFTR our data suggests that an external anion-binding site on the channel itself is involved. Overall, our results show that luminal HCO3-acts as a potent inhibitor of CFTR channels (and by inference CFTR-mediated secretion), under normal physiological conditions. These data have implications not only for current models of pancreatic duct cell HCO3-transport, but also for other bicarbonate-secreting tissues, such as the liver, GI tract and lungs.
Original languageEnglish
Pages (from-to)S12-S15
Number of pages4
JournalJournal of Korean Medical Sciences
Issue numberSuppl
Publication statusPublished - 2000

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