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Modulation of O2 Sensitive K+ Channels by AMP-Activated Protein Kinase
Arterial Chemoreceptors
  • Mark L. Dallas
  • J. L. Scragg
  • Christopher N. Wyatt, Wright State University - Main Campus
  • Fiona A. Ross
  • D. Grahame Hardie
  • A. Mark Evans
  • Chris Peers
Document Type
Conference Proceeding
Publication Date
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Catalog Record
Hypoxic inhibition of K+ channels in type I cells is believed to be of central importance in carotid body chemotransduction. We have recently suggested that hypoxic channel inhibition is mediated by AMP-activated protein kinase (AMPK). Here, we have further explored the modulation by AMPK of recombinant K+ channels (expressed in HEK293 cells) whose native counterparts are considered O2-sensitive in the rat carotid body. Inhibition of maxiK channels by AMPK activation with AICAR was found to be independent of [Ca2+]i and occurred regardless of whether the α subunit was co-expressed with an auxiliary β subunit. All effects of AICAR were fully reversed by the AMPK inhibitor compound C. MaxiK channels were also inhibited by the novel AMPK activator A-769662 and by intracellular dialysis with the constitutively active, truncated AMPK mutant, T172D. The molecular identity of the O2-sensitive leak K+ conductance in rat type I cells remains unclear, but shares similarities with TASK-1 and TASK-3. Recombinant TASK-1 was insensitive to AICAR. However, TASK-3 was inhibited by either AICAR or A-769662 in a manner which was reversed by compound C. These data highlight a role for AMPK in the modulation of two proposed O2 sensitive K+ channels found in the carotid body.

Presented at the 17th International Society for Arterial Chemoreception (ISAC) Meeting, Valladolid, Spain.

Citation Information
Mark L. Dallas, J. L. Scragg, Christopher N. Wyatt, Fiona A. Ross, et al.. "Modulation of O2 Sensitive K+ Channels by AMP-Activated Protein Kinase" Arterial Chemoreceptors Vol. 648 (2009) p. 57 - 63 ISSN: 978-90-481-2258-5
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