Inwardly rectifying potassium (IRK) currents are correlated with IRK subunit expression in rat nucleus accumbens medium spiny neurons

Paul G. Mermelstein, Wen Jie Song, Tatiana Tkatch, Zhen Yan, D. James Surmeier

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66 Scopus citations

Abstract

Inwardly rectifying K+ (IRK) channels are critical for shaping cell excitability. Whole-cell patch-clamp and single-cell RT-PCR techniques were used to characterize the inwardly rectifying K + currents found in projection neurons of the rat nucleus accumbens. Inwardly rectifying currents were highly selective for K+ and blocked by low millimolar concentrations of Cs+ or Ba2+. In a subset of neurons, the inwardly rectifying current appeared to inactivate at hyperpolarized membrane potentials. In an attempt to identify this subset, neurons were profiled using single-cell RT-PCR. Neurons expressing substance P mRNA exhibited noninactivating inward rectifier currents; whereas neurons expressing enkephalin mRNA exhibited inactivating inward rectifier currents. The inactivation of the inward rectifier was correlated with the expression of IRK1 mRNA. These results demonstrate a clear physiological difference in the properties of medium spiny neurons and suggest that this difference could influence active state transitions driven by cortical and hippocampal excitatory input.

Original languageEnglish (US)
Pages (from-to)6650-6661
Number of pages12
JournalJournal of Neuroscience
Volume18
Issue number17
DOIs
StatePublished - Sep 1 1998

Keywords

  • Enkephalin
  • Inward rectifier
  • Medium spiny neurons
  • Potassium channels
  • Single-cell RT-PCR
  • Substance P
  • Ventral striatum
  • Voltage clamp

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