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Pflügers Archiv

, Volume 438, Issue 6, pp 879–882 | Cite as

Effect of the inactivating "ball" peptide of Shaker B on intermediate conductance Ca2+-dependent inwardly rectifying K+ channels of HeLa cells

  • G. Riquelme
  • A. M. Fernández
  • J. A. Encinar
  • J. M. González-Ros
  • F. V. Sepúlveda
Original Article
  • 21 Downloads

Abstract.

The patch-clamp technique was used to study the effect of intracellularly added inactivating "ball" peptide (BP) of the Shaker B K+ channel upon Ca2+-dependent inwardly rectifying K+ channels of the intermediate conductance type expressed in HeLa cells. Intracellular BP caused only moderate inhibition of outward K+ currents when assayed at an intracellular Ca2+ concentration of 100 nmol/l. Increasing intracellular Ca2+ levels led in itself to some voltage-dependent blockade of K+ currents, which was absent when high extracellular K+ was used. An additional strong blockade by intracellular BP was nevertheless observed both in Na+- and K+-rich extracellular solutions. A non-inactivating BP analogue had no effect. At this higher intracellular Ca2+ concentration the inhibition of these intermediate conductance Ca2+-dependent channels by BP was voltage-dependent, being absent at hyperpolarizing potentials, and could be relieved by increasing extracellular K+. These data suggest that BP acts at an internal pore site in Ca2+-dependent intermediate conductance K+ channels of HeLa cells, and that these might possess a receptor site for the peptide similar to that of other K+ channels such as Ca2+-activated maxi-K+ channels.

Intermediate conductance Ca2+-dependent K+ channel Shaker B inactivating peptide 

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Copyright information

© Springer-Verlag 0000

Authors and Affiliations

  • G. Riquelme
    • 1
  • A. M. Fernández
    • 2
  • J. A. Encinar
    • 2
  • J. M. González-Ros
    • 2
  • F. V. Sepúlveda
    • 1
  1. 1.Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70058, Santiago, Chile
  2. 2.Centro de Biología Molecular y Celular,Universidad Miguel Hernández, E-03206 Elche, Alicante, Spain

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