A Ba2+-resistant, acid-sensitive K+ conductance in Na+-absorbing H441 human airway epithelial cells

Sarah K. Inglis, Sean G. Brown, Maree J. Constable, Niall McTavish, Richard E. Olver, Stuart M. Wilson

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Abstract

By analysis of whole cell membrane currents in Na+-absorbing H441 human airway epithelial cells, we have identified a K+ conductance (GK) resistant to Ba2+ but sensitive to bupivacaine or extracellular acidification. In polarized H441 monolayers, we have demonstrated that bupivacaine, lidocaine, and quinidine inhibit basolateral membrane K+ current (IBl) whereas Ba2+ has only a weak inhibitory effect. IBl was also inhibited by basolateral acidification, and, although subsequent addition of bupivacaine caused a further fall in IBl, acidification had no effect after bupivacaine, demonstrating that cells grown under these conditions express at least two different bupivacaine-sensitive K+ channels, only one of which is acid sensitive. Basolateral acidification also inhibited short-circuit current (ISC), and basolateral bupivacaine, lidocaine, quinidine, and Ba2+ inhibited ISC at concentrations similar to those needed to inhibit IBl, suggesting that the K+ channels underlying IBl are part of the absorptive mechanism. Analyses using RT-PCR showed that mRNA encoding several two-pore domain K+ (K2P) channels was detected in cells grown under standard conditions (TWIK-1, TREK-1, TASK-2, TWIK-2, KCNK-7, TASK-3, TREK-2, THIK-1, and TALK-2). We therefore suggest that K2P channels underlie GK in unstimulated cells and so maintain the driving force for Na+ absorption. Since this ion transport process is vital to lung function, K2P channels thus play an important but previously undocumented role in pulmonary physiology.
Original languageEnglish
Pages (from-to)1304-1312
Number of pages9
JournalAmerican Journal of Physiology: Lung Cellular and Molecular Physiology
Volume292
DOIs
StatePublished - 2 Feb 2007

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Bupivacaine
Epithelial Cells
Acids
Quinidine
Lidocaine
Lung
Ion Transport
Cell Membrane
Polymerase Chain Reaction
Messenger RNA
Membranes

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Inglis, Sarah K.; Brown, Sean G.; Constable, Maree J.; McTavish, Niall; Olver, Richard E.; Wilson, Stuart M. / A Ba2+-resistant, acid-sensitive K+ conductance in Na+-absorbing H441 human airway epithelial cells.

In: American Journal of Physiology: Lung Cellular and Molecular Physiology, Vol. 292, 02.02.2007, p. 1304-1312.

Research output: Contribution to journalArticle

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abstract = "By analysis of whole cell membrane currents in Na+-absorbing H441 human airway epithelial cells, we have identified a K+ conductance (GK) resistant to Ba2+ but sensitive to bupivacaine or extracellular acidification. In polarized H441 monolayers, we have demonstrated that bupivacaine, lidocaine, and quinidine inhibit basolateral membrane K+ current (IBl) whereas Ba2+ has only a weak inhibitory effect. IBl was also inhibited by basolateral acidification, and, although subsequent addition of bupivacaine caused a further fall in IBl, acidification had no effect after bupivacaine, demonstrating that cells grown under these conditions express at least two different bupivacaine-sensitive K+ channels, only one of which is acid sensitive. Basolateral acidification also inhibited short-circuit current (ISC), and basolateral bupivacaine, lidocaine, quinidine, and Ba2+ inhibited ISC at concentrations similar to those needed to inhibit IBl, suggesting that the K+ channels underlying IBl are part of the absorptive mechanism. Analyses using RT-PCR showed that mRNA encoding several two-pore domain K+ (K2P) channels was detected in cells grown under standard conditions (TWIK-1, TREK-1, TASK-2, TWIK-2, KCNK-7, TASK-3, TREK-2, THIK-1, and TALK-2). We therefore suggest that K2P channels underlie GK in unstimulated cells and so maintain the driving force for Na+ absorption. Since this ion transport process is vital to lung function, K2P channels thus play an important but previously undocumented role in pulmonary physiology.",
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A Ba2+-resistant, acid-sensitive K+ conductance in Na+-absorbing H441 human airway epithelial cells. / Inglis, Sarah K.; Brown, Sean G.; Constable, Maree J.; McTavish, Niall; Olver, Richard E.; Wilson, Stuart M.

In: American Journal of Physiology: Lung Cellular and Molecular Physiology, Vol. 292, 02.02.2007, p. 1304-1312.

Research output: Contribution to journalArticle

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T1 - A Ba2+-resistant, acid-sensitive K+ conductance in Na+-absorbing H441 human airway epithelial cells

AU - Inglis,Sarah K.

AU - Brown,Sean G.

AU - Constable,Maree J.

AU - McTavish,Niall

AU - Olver,Richard E.

AU - Wilson,Stuart M.

PY - 2007/2/2

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N2 - By analysis of whole cell membrane currents in Na+-absorbing H441 human airway epithelial cells, we have identified a K+ conductance (GK) resistant to Ba2+ but sensitive to bupivacaine or extracellular acidification. In polarized H441 monolayers, we have demonstrated that bupivacaine, lidocaine, and quinidine inhibit basolateral membrane K+ current (IBl) whereas Ba2+ has only a weak inhibitory effect. IBl was also inhibited by basolateral acidification, and, although subsequent addition of bupivacaine caused a further fall in IBl, acidification had no effect after bupivacaine, demonstrating that cells grown under these conditions express at least two different bupivacaine-sensitive K+ channels, only one of which is acid sensitive. Basolateral acidification also inhibited short-circuit current (ISC), and basolateral bupivacaine, lidocaine, quinidine, and Ba2+ inhibited ISC at concentrations similar to those needed to inhibit IBl, suggesting that the K+ channels underlying IBl are part of the absorptive mechanism. Analyses using RT-PCR showed that mRNA encoding several two-pore domain K+ (K2P) channels was detected in cells grown under standard conditions (TWIK-1, TREK-1, TASK-2, TWIK-2, KCNK-7, TASK-3, TREK-2, THIK-1, and TALK-2). We therefore suggest that K2P channels underlie GK in unstimulated cells and so maintain the driving force for Na+ absorption. Since this ion transport process is vital to lung function, K2P channels thus play an important but previously undocumented role in pulmonary physiology.

AB - By analysis of whole cell membrane currents in Na+-absorbing H441 human airway epithelial cells, we have identified a K+ conductance (GK) resistant to Ba2+ but sensitive to bupivacaine or extracellular acidification. In polarized H441 monolayers, we have demonstrated that bupivacaine, lidocaine, and quinidine inhibit basolateral membrane K+ current (IBl) whereas Ba2+ has only a weak inhibitory effect. IBl was also inhibited by basolateral acidification, and, although subsequent addition of bupivacaine caused a further fall in IBl, acidification had no effect after bupivacaine, demonstrating that cells grown under these conditions express at least two different bupivacaine-sensitive K+ channels, only one of which is acid sensitive. Basolateral acidification also inhibited short-circuit current (ISC), and basolateral bupivacaine, lidocaine, quinidine, and Ba2+ inhibited ISC at concentrations similar to those needed to inhibit IBl, suggesting that the K+ channels underlying IBl are part of the absorptive mechanism. Analyses using RT-PCR showed that mRNA encoding several two-pore domain K+ (K2P) channels was detected in cells grown under standard conditions (TWIK-1, TREK-1, TASK-2, TWIK-2, KCNK-7, TASK-3, TREK-2, THIK-1, and TALK-2). We therefore suggest that K2P channels underlie GK in unstimulated cells and so maintain the driving force for Na+ absorption. Since this ion transport process is vital to lung function, K2P channels thus play an important but previously undocumented role in pulmonary physiology.

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DO - 10.1152/ajplung.00424.2006

M3 - Article

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SP - 1304

EP - 1312

JO - American Journal of Physiology: Lung Cellular and Molecular Physiology

T2 - American Journal of Physiology: Lung Cellular and Molecular Physiology

JF - American Journal of Physiology: Lung Cellular and Molecular Physiology

SN - 1040-0605

ER -