Molecular Identity of Dendritic Voltage-Gated Sodium Channels

Abstract

Counting Na + Channels One by One Understanding how nerve cells integrate their synaptic inputs and generate their output signals requires the identification of voltage-dependent ion channels on the axo-somato-dendritic surface of central neurons. Using improved ultrastructural immunocytochemistry techniques, Lorincz and Nusser (p. 906 ) found that a newly described voltage-gated sodium channel, Nav1.6, was present not only at nodes of Ranvier and axon initial segments but also at much lower, but functionally significant levels, in dendrites of CA1 pyramidal cells. However, other brain Na + channels were not present in these dendrites, suggesting that dendritic sodium spikes result from somatic activation of this particular type of sodium channel.