Delayed rectifier currents in rat globus pallidus neurons are attributable to Kv2.1 and Kv3.1/3.2 K+ channels

Gytis Baranauskas, Tatiana Tkatch, D. James Surmeier*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

The symptoms of Parkinson disease are thought to result in part from increased burst activity in globus pallidus neurons. To gain a better understanding of the factors governing this activity, we studied delayed rectifier K+ conductances in acutely isolated rat globus pallidus (GP) neurons, using whole-cell voltage-clamp and single-cell RT-PCR techniques. From a holding potential of -40 mV, depolarizing voltage steps in identified GP neurons evoked slowly inactivating K+ currents. Analysis of the tail currents revealed rapidly and slowly deactivating currents of similar amplitude. The fast component of the current deactivated with a time constant of 11.1 ± 0.8 msec at -40 mV and was blocked by micromolar concentrations of 4-AP and TEA (K(D) ~140 μM). The slow component of the current deactivated with a time constant of 89 ± 10 msec at -40 mV and was less sensitive to TEA (K(D) = 0.8 mM) and 4-AP (K(D) ~6 mM). Organic antagonists of Kv1 family channels had little or no effect on somatic currents. These properties are consistent with the hypothesis that the rapidly deactivating current is attributable to Kv3.1/3.2 channels and the slowly deactivating current to Kv2.1-containing channels. Semiquantitative single-cell RT-PCR analysis of Kv3 and Kv2 family mRNAs supported this conclusion. An alteration in the balance of these two channel types could underlie the emergence of burst firing after dopamine-depleting lesions.

Original languageEnglish (US)
Pages (from-to)6394-6404
Number of pages11
JournalJournal of Neuroscience
Volume19
Issue number15
DOIs
StatePublished - Aug 1 1999

Keywords

  • 4-AP
  • Delayed rectifier
  • Globus pallidus
  • Kv2.1
  • Kv3.1/3.2
  • Potassium channels
  • Single- cell RT-PCR
  • TEA
  • Voltage clamp

ASJC Scopus subject areas

  • Neuroscience(all)

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