Increasing SK2 channel activity impairs associative learning

Bridget M. McKay, M. Matthew Oh, Roberto Galvez, Jeffrey Burgdorf, Roger A. Kroes, Craig Weiss, John P. Adelman, Joseph R. Moskal, John F. Disterhoft

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Enhanced intrinsic neuronal excitability of hippocampal pyramidal neurons via reductions in the postburst afterhyperpolarization (AHP) has been hypothesized to be a biomarker of successful learning. This is supported by considerable evidence that pharmacologic enhancement of neuronal excitability facilitates learning. However, it has yet to be demonstrated that pharmacologic reduction of neuronal excitability restricted to the hippocampus can retard acquisition of a hippocampus-dependent task. Thus, the present study was designed to address this latter point using a small conductance potassium (SK) channel activator NS309 focally applied to the dorsal hippocampus. SK channels are important contributors to intrinsic excitability, as measured by the medium postburst AHP. NS309 increased the medium AHP and reduced excitatory postsynaptic potential width of CA1 neurons in vitro. In vivo, NS309 reduced the spontaneous firing rate of CA1 pyramidal neurons and impaired trace eyeblink conditioning in rats. Conversely, trace eyeblink conditioning reduced levels of SK2 channel mRNA and protein in the hippocampus. Therefore, the present findings indicate that modulation of SK channels is an important cellular mechanism for associative learning and further support postburst AHP reductions in hippocampal pyramidal neurons as a biomarker of successful learning.

Original languageEnglish (US)
Pages (from-to)863-870
Number of pages8
JournalJournal of neurophysiology
Volume108
Issue number3
DOIs
StatePublished - Aug 1 2012

Keywords

  • Afterhyperpolarization
  • Intrinsic excitability
  • NS309
  • Trace eyeblink conditioning

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology

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