Subcellular distribution of persistent sodium conductance in cortical pyramidal neurons

Arik Shvartsman, Oron Kotler, Ohad Stoler, Yana Khrapunsky, Israel Melamed, Ilya A. Fleidervish

Research output: Contribution to journalArticlepeer-review

Abstract

Cortical pyramidal neurons possess a persistent Na1 current (INaP), which, in contrast to the larger transient current, does not undergo rapid inactivation. Although relatively quite small, INaP is active at subthreshold voltages and therefore plays an important role in neuronal input–output processing. The subcellular distribution of channels responsible for INaP and the mechanisms that render them persistent are not known. Using high-speed fluorescence Na1 imaging and whole-cell recordings in brain slices obtained from mice of either sex, we reconstructed the INaP elicited by slow voltage ramps in soma and processes of cortical pyramidal neurons. We found that in all neuronal compartments, the relationship between persistent Na1 conductance and membrane voltage has the shape of a Boltzmann function. Although the density of channels underlying INaP was about twofold lower in the axon initial segment (AIS) than in the soma, the axonal channels were activated by;10 mV less depolarization than were somatic channels. This difference in voltage dependence explains why, at functionally critical subthreshold voltages, most INaP originates in the AIS. Finally, we show that endogenous polyamines constrain INaP availability in both somatodendritic and axonal compartments of nondialyzed cortical neurons.

Original languageEnglish
Pages (from-to)6190-6201
Number of pages12
JournalJournal of Neuroscience
Volume41
Issue number29
DOIs
StatePublished - 21 Jul 2021

Keywords

  • Action potential
  • Axon initial segment
  • Neocortex
  • Polyamines
  • Pyramidal neuron
  • Sodium channel

Fingerprint

Dive into the research topics of 'Subcellular distribution of persistent sodium conductance in cortical pyramidal neurons'. Together they form a unique fingerprint.

Cite this