Electrolyte transport in the mouse trachea: No evidence for a contribution of luminal K+ conductance

Schreiber, R., Murle, B., Sun, J. and Kunzelmann, K. (2002) Electrolyte transport in the mouse trachea: No evidence for a contribution of luminal K+ conductance. Journal of Membrane Biology, 189 2: 143-151. doi:10.1007/s00232-002-1009-5

Author Schreiber, R.
Murle, B.
Sun, J.
Kunzelmann, K.
Title Electrolyte transport in the mouse trachea: No evidence for a contribution of luminal K+ conductance
Journal name Journal of Membrane Biology   Check publisher's open access policy
ISSN 0022-2631
Publication date 2002-09-15
Sub-type Article (original research)
DOI 10.1007/s00232-002-1009-5
Volume 189
Issue 2
Start page 143
End page 151
Total pages 9
Editor W.R. Lowenstein
Place of publication New York, NY, U. S. A.
Publisher Springer-Verlag New York Inc
Collection year 2002
Language eng
Subject C1
270104 Membrane Biology
780105 Biological sciences
Abstract Recent studies on frog skin acini have challenged the question whether Cl- secretion or Na+ absorption in the airways is driven by luminal K+ channels in series to a basolateral K+ conductance. We examined the possible role of luminal K+ channels in electrolyte transport in mouse trachea in Ussing-chamber experiments. Tracheas of both normal and CFTR (-/-) mice showed a dominant amiloride-sensitive Na+ absorption under both, control conditions and after cAMP-dependent stimulation. The lumen-negative transepithelial voltage was enhanced after application of IBMX and forskolin and Cl- secretion was activated. Electrolyte secretion induced by IBMX and forskolin was inhibited by luminal glibenclamide and the blocker of basolateral Na(+)2Cl(-)K(+) cotransporter azosemide. Similarly, the compound 29313, a blocker of basolateral KCNQ1/KCNE3 K+ channels effectively blocked Cl- secretion when applied to either the luminal or basolateral side of the epithelium. RT-PCR analysis suggested expression of additional K+ channels in tracheal epithelial cells such as Slo1 and Kir6.2. However, we did not detect any functional evidence for expression of luminal K+ channels in mouse airways, using luminal 29313, clotrimazole and Ba2+ or different K+ channel toxins such as charybdotoxin, apamin and alpha-dendrotoxin. Thus, the present study demonstrates Cl- secretion in mouse airways, which depends on basolateral Na(+)2Cl(-)K(+) cotransport and luminal CFTR and non-CFTR Cl- channels. Cl- secretion is maintained by the activity of basolateral K+ channels, while no clear evidence was found for the presence of a luminal K+ conductance.
Keyword Biochemistry & Molecular Biology
Cell Biology
Mouse Airways
Trachea K+ Conductance
Cystic Fibrosis
Epithelial Transport
Airway Surface Liquid
Bronchial Epithelial-cells
Cystic-fibrosis Airways
Mediated Cl Secretion
Ion Conductances
Na+ Conductance
Apical Membrane
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biomedical Sciences Publications
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Created: Tue, 14 Aug 2007, 19:00:34 EST