Dynamic potassium channel distributions during axonal development prevent aberrant firing patterns

Ian Vabnick, James Trimmer, Thomas L. Schwarz, S. Rock Levinson, Dipesh Risal, Peter Shrager

Research output: Contribution to journalArticle

145 Scopus citations

Abstract

The distribution and function of Shaker-related K+ channels were studied with immunofluorescence and electrophysiology in sciatic nerves of developing rats. At nodes of Ranvier, Na+ channel clustering occurred very early (postnatal days 1-3). Although K+ channels were not yet segregated at most of these sites, they were directly involved in action potential generation, reducing duration, and the refractory period. At ~1 week, K+ channel clusters were first seen but were within the nodal gap and in paranodes, and only later (weeks 2-4) were they shifted to juxtaparanodal regions: K+ channel function was most dramatic during this transition period, with block producing repetitive firing in response to single stimuli. As K+ channels were increasingly sequestered in juxtaparanodes, conduction became progressively insensitive to K+ channel block. Over the first 3 weeks, K+ channel clustering was often asymmetric, with channels exclusively in the distal paranode in ~40% of cases. A computational model suggested a mechanism for the firing patterns observed, and the results provide a role for K+ channels in the prevention of aberrant excitation as myelination proceeds during development.

Original languageEnglish (US)
Pages (from-to)747-758
Number of pages12
JournalJournal of Neuroscience
Volume19
Issue number2
StatePublished - Jan 15 1999
Externally publishedYes

Keywords

  • Axons
  • Development
  • Myelin
  • Node of Ranvier
  • Potassium channels
  • Schwann cell

ASJC Scopus subject areas

  • Neuroscience(all)

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    Vabnick, I., Trimmer, J., Schwarz, T. L., Levinson, S. R., Risal, D., & Shrager, P. (1999). Dynamic potassium channel distributions during axonal development prevent aberrant firing patterns. Journal of Neuroscience, 19(2), 747-758.