Altered subthreshold sodium currents and disrupted firing patterns in Purkinje neurons of Scn8a mutant mice

Indira M. Raman*, Leslie K. Sprunger, Miriam H. Meisler, Bruce P. Bean

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

320 Scopus citations

Abstract

Sodium currents and action potentials were characterized in Purkinje neurons from ataxic mice lacking expression of the sodium channel Scn8a. Peak transient sodium current was ~60% of that in normal mice, but subthreshold sodium current was affected much more. Steady-state current elicited by voltage ramps was reduced to ~30%, and resurgent sodium current, an unusual transient current elicited on repolarization following strong depolarizations, was reduced to 8%-18%. In jolting mice, with a missense mutation in Scn8a, steady-state and resurgent current were also reduced, with altered voltage dependence and kinetics. Both spontaneous firing and evoked bursts of spikes were diminished in cells from null and jolting mice. Evidently Scn8a channels carry most subthreshold sodium current and are crucial for repetitive firing.

Original languageEnglish (US)
Pages (from-to)881-891
Number of pages11
JournalNeuron
Volume19
Issue number4
DOIs
StatePublished - Oct 1997

ASJC Scopus subject areas

  • Neuroscience(all)

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