K+ channel distribution and clustering in developing and hypomyelinated axons of the optic nerve

Matthew N. Rasband, James Trimmer, Elior Peles, S. Rock Levinson, Peter Shrager

Research output: Contribution to journalArticlepeer-review

95 Scopus citations

Abstract

The localization of Shaker-type K+ channels in specialized domains of myelinated central nervous system axons was studied during development of the optic nerve. In adult rats Kv1.1, Kv1.2, Kv1.6, and the cytoplasmic β- subunit Kvβ2 were colocalized in juxtaparanodal zones. During development, clustering of K+ channels lagged behind that for nodal Na+ channels by about 5 days. In contrast to the PNS, K+ channels were initially expressed fully segregated from nodes and paranodes, the latter identified by immunofluorescence of Caspr, a component of axoglial junctions. Clusters of K+ channels were first detected at postnatal day 14 (P14) at a limited number of sites. Expression increased until all juxtaparanodes had immunoreactivity by P40. Developmental studies in hypomyelinating Shiverer mice revealed dramatically disrupted axoglial junctions, aberrant Na+ channel clusters, and little or no detectable clustering of K+ channels at all ages. These results suggest that in the optic nerve, compact myelin and normal axoglial junctions are essential for proper K+ channel clustering and localization.

Original languageEnglish (US)
Pages (from-to)319-331
Number of pages13
JournalJournal of Neurocytology
Volume28
Issue number4-5
StatePublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)
  • Anatomy
  • Cell Biology
  • Histology

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