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Pflügers Archiv

, Volume 418, Issue 1–2, pp 68–73 | Cite as

ATP-sensitive and Ca-activated K channels in vertebrate axons: novel links between metabolism and excitability

  • Peter Jonas
  • Duk -Su Koh
  • Knut Kampe
  • Markus Hermsteiner
  • Werner Vogel
Excitable Tissues and Central Nervous Physiology

Abstract

Two types of metabolically regulated K channels have been identified for the first time in enzymatically demyelinated fibres of amphibian sciatic nerve using the patch-clamp technique. A maxi K channel with a single-channel conductance of 132 pS (105 mM K on both sides of the membrane, 15 °C) is activated both by micromolar concentrations of internal Ca and by depolarization. A second type of K channel with a conductance of 44 pS is inhibited by intracellular adenosine 5′-triphosphate (ATP) with a half-maximal inhibitory concentration (IC50) of 35 μM. It is blocked by submicromolar concentrations of external glibenclamide. Both channels are sensitive to external tetraethylammonium chloride (IC50 = 0.2 mM for the maxi K channel and 4.2 mM for the ATP-sensitive channel). They may be part of a complex feedback system regulating axonal excitability under various metabolic conditions.

Key words

Patch clamp Myelinated nerve fibre ATP-Sensitive K channel Ca-Activated K channel Hypoxia Diabetic neuropathy 

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Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Peter Jonas
    • 1
  • Duk -Su Koh
    • 1
  • Knut Kampe
    • 1
  • Markus Hermsteiner
    • 1
  • Werner Vogel
    • 1
  1. 1.Physiologisches Institut der Justus-Liebig-UniversitätGiessenFederal Republic of Germany

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