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Erg K+ currents modulate excitability in mouse mitral/tufted neurons

  • Wiebke Hirdes
  • Nora Napp
  • Iris Wulfsen
  • Michaela Schweizer
  • Jürgen R. Schwarz
  • Christiane K. BauerEmail author
Ion Channels, Receptors and Transporters

Abstract

Different erg (ether-à-go-go-related gene; Kv11) K+ channel subunits are expressed throughout the brain. Especially mitral cells of the olfactory bulb are stained intensely by erg1a, erg1b, erg2, and erg3 antibodies. This led us to study the erg current in mitral/tufted (M/T) neurons from mouse olfactory bulb in primary culture. M/T neurons were identified by their morphology and presence of mGluR1 receptors, and RT-PCR demonstrated the expression of all erg subunits in cultured M/T neurons. Using an elevated external K+ concentration, a relatively uniform erg current was recorded in the majority of M/T cells and isolated with the erg channel blocker E-4031. With 4-s depolarizations, the erg current started to activate at −65 mV and exhibited half maximal activation at −51 mV. An increase in the external K+ concentration resulted in an increase in erg whole-cell conductance. The specific group 1 mGluR agonist, DHPG, which depolarizes mitral cells, reduced erg channel availability. DHPG accelerated erg current deactivation, reduced the maximum current amplitude, and shifted availability and activation curves to more depolarized potentials. A pharmacological block of erg channels depolarized the resting potential of M/T cells and clearly demonstrated the involvement of erg channels in the control of mitral cell excitability.

Keywords

Olfactory bulb Mitral cells HERG Kv11 mGluR1 

Notes

Acknowledgements

We thank Saskia Siegel, Barbara Merz, Telse Kock, Annett Hasse and Dr. Susanne Fehr for their help. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 444, A3; SCHW 292/14-1).

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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Wiebke Hirdes
    • 1
  • Nora Napp
    • 2
  • Iris Wulfsen
    • 3
  • Michaela Schweizer
    • 1
  • Jürgen R. Schwarz
    • 1
  • Christiane K. Bauer
    • 2
    Email author
  1. 1.Institut für Neurale Signalverarbeitung, ZMNHUniversitätsklinikum Hamburg-Eppendorf, Universität HamburgHamburgGermany
  2. 2.Institut für Vegetative Physiologie und Pathophysiologie, Zentrum für Experimentelle MedizinUniversitätsklinikum Hamburg-Eppendorf, Universität HamburgHamburgGermany
  3. 3.Institut für Pharmakologie für PharmazeutenUniversitätsklinikum Hamburg-Eppendorf, Universität HamburgHamburgGermany

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