Molecular Identity of Dendritic Voltage-Gated Sodium Channels

Science. 2010 May 14;328(5980):906-9. doi: 10.1126/science.1187958.

Abstract

Active invasion of the dendritic tree by action potentials (APs) generated in the axon is essential for associative synaptic plasticity and neuronal ensemble formation. In cortical pyramidal cells (PCs), this AP back-propagation is supported by dendritic voltage-gated Na+ (Nav) channels, whose molecular identity is unknown. Using a highly sensitive electron microscopic immunogold technique, we revealed the presence of the Nav1.6 subunit in hippocampal CA1 PC proximal and distal dendrites. Here, the subunit density is lower by a factor of 35 to 80 than that found in axon initial segments. A gradual decrease in Nav1.6 density along the proximodistal axis of the dendritic tree was also detected without any labeling in dendritic spines. Our results reveal the characteristic subcellular distribution of the Nav1.6 subunit, identifying this molecule as a key substrate enabling dendritic excitability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Axons / chemistry
  • Axons / physiology
  • CA1 Region, Hippocampal / chemistry*
  • CA1 Region, Hippocampal / physiology
  • CA1 Region, Hippocampal / ultrastructure
  • Cell Membrane / chemistry
  • Dendrites / chemistry*
  • Dendrites / physiology
  • Dendrites / ultrastructure
  • Dendritic Spines / chemistry
  • Fluorescent Antibody Technique
  • Freeze Fracturing
  • Immunohistochemistry
  • Ion Channel Gating
  • Male
  • Microscopy, Immunoelectron
  • NAV1.1 Voltage-Gated Sodium Channel
  • NAV1.6 Voltage-Gated Sodium Channel
  • Nerve Tissue Proteins / analysis
  • Ranvier's Nodes / chemistry
  • Rats
  • Rats, Wistar
  • Sodium Channels / analysis*

Substances

  • NAV1.1 Voltage-Gated Sodium Channel
  • NAV1.6 Voltage-Gated Sodium Channel
  • Nerve Tissue Proteins
  • Scn1a protein, rat
  • Scn8a protein, rat
  • Sodium Channels