Journal article
Basolateral K+ channels in airway epithelia. I. Regulation by Ca2+ and block by charybdotoxin
American journal of physiology. Lung cellular and molecular physiology, Vol.258(6), pp.L334-L342
06/01/1990
DOI: 10.1152/ajplung.1990.258.6.L334
PMID: 1694404
Abstract
In airway epithelia, adenosine 3',5'-cyclic monophosphate (cAMP) stimulates Cl- secretion by activating apical membrane Cl- channels and basolateral membrane K+ channels. Cl- channels are regulated by cAMP-dependent phosphorylation, whereas K+ channels are regulated by the cytosolic Ca2+ concentration, [Ca2+]c. Our recent observation that cAMP increases [Ca2+]c suggested that cAMP might indirectly regulate K+ channels by increasing [Ca2+]c. To study regulation of K+ channels we measured 86Rb efflux, single K+ channels in membrane patches, and [Ca2+]c with the fluorescent indicator fura-2. Isoproterenol and Ca2+ ionophore, A23187, transiently increased [Ca2+]c and transiently stimulated 86Rb efflux. Stimulation of 86Rb efflux resulted from release of intracellular Ca2+ stores. 86Rb efflux was blocked by Ba2+ or charybdotoxin, but not by tetraethylammonium. Charybdotoxin prevented all of the 86Rb efflux that was stimulated by A23187 or by forskolin. Charybdotoxin also blocked the low-conductance inwardly rectifying K+ channel (KCLIC) in membrane patches. These results indicate that the KCLIC channel is responsible for the Ca2(+)-dependent increase in K+ permeability in airway epithelial cells. They also indicate that cAMP-induced release of intracellular Ca2+ is sufficient to activate K+ channels.
Details
- Title: Subtitle
- Basolateral K+ channels in airway epithelia. I. Regulation by Ca2+ and block by charybdotoxin
- Creators
- John D McCann - Howard Hughes Medical Institute, Department of Physiology, University of Iowa, College of Medicine, Iowa City 52242Jim Matsuda - Howard Hughes Medical Institute, Department of Physiology, University of Iowa, College of Medicine, Iowa City 52242María Garcia - Howard Hughes Medical Institute, Department of Physiology, University of Iowa, College of Medicine, Iowa City 52242Greg Kaczorowski - Howard Hughes Medical Institute, Department of Physiology, University of Iowa, College of Medicine, Iowa City 52242Michael J Welsh - Howard Hughes Medical Institute, Department of Physiology, University of Iowa, College of Medicine, Iowa City 52242
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Lung cellular and molecular physiology, Vol.258(6), pp.L334-L342
- DOI
- 10.1152/ajplung.1990.258.6.L334
- PMID
- 1694404
- NLM abbreviation
- Am J Physiol Lung Cell Mol Physiol
- ISSN
- 1040-0605
- eISSN
- 1522-1504
- Publisher
- American Physiological Society
- Language
- English
- Date published
- 06/01/1990
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Fraternal Order of Eagles Diabetes Research Center; Neurosurgery; Internal Medicine
- Record Identifier
- 9984020994702771
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