Journal article
Apical membrane Cl- channels in airway epithelia: anion selectivity and effect of an inhibitor
American Journal of Physiology: Cell Physiology, Vol.259(2), pp.C295-C301
08/01/1990
DOI: 10.1152/ajpcell.1990.259.2.C295
PMID: 1696430
Abstract
Previous work has investigated the anion selectivity of transepithelial Cl- secretion by airway epithelia and its inhibition by the Cl(-)-channel blocker 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB). Here we report the anion selectivity of the apical membrane and of the outwardly rectifying Cl- channel and the effect of NPPB on the Cl- channel. The anion selectivity sequence of the apical membrane determined with conventional microelectrodes in the native epithelium was SCN- greater than I- greater than Br- greater than NO3- approximately Cl- much greater than SO(4)2- approximately gluconate-. This contrasts with the observation that Cl- and Br- support transepithelial secretion but that I- does not. Thus the anion selectivity of transepithelial transport is determined by the basolateral membrane Cl- entry step. The anion selectivity of the outwardly rectifying Cl- channel studied in excised patches was the same as that of the apical membrane. We also found that NPPB reversibly blocked the outwardly rectifying Cl- channel from both the internal and external surfaces of the patch. NPPB, 10 microM, completely blocked the channel; lower concentrations caused a decrease in the probability of finding the channel in the open state. NPPB also caused the appearance of a subconductance state of the channel, an occurrence which is rarely observed in the absence of NPPB. These data provide further support for the conclusion that the outwardly rectifying Cl- channel is responsible for Cl- exit from the cell across the apical membrane.
Details
- Title: Subtitle
- Apical membrane Cl- channels in airway epithelia: anion selectivity and effect of an inhibitor
- Creators
- Ming Li - Howard Hughes Medical Institute, Department of Internal Medicine,University of Iowa College of Medicine, Iowa City 52242John D McCann - Howard Hughes Medical Institute, Department of Internal Medicine,University of Iowa College of Medicine, Iowa City 52242Michael J Welsh - Howard Hughes Medical Institute, Department of Internal Medicine,University of Iowa College of Medicine, Iowa City 52242
- Resource Type
- Journal article
- Publication Details
- American Journal of Physiology: Cell Physiology, Vol.259(2), pp.C295-C301
- DOI
- 10.1152/ajpcell.1990.259.2.C295
- PMID
- 1696430
- ISSN
- 0363-6143
- eISSN
- 1522-1563
- Language
- English
- Date published
- 08/01/1990
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Neurosurgery; Internal Medicine
- Record Identifier
- 9984020860802771
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