Resurgent current and voltage sensor trapping enhanced activation by a beta-scorpion toxin solely in Nav1.6 channel. Significance in mice Purkinje neurons

J Biol Chem. 2006 Jul 21;281(29):20326-37. doi: 10.1074/jbc.M600565200. Epub 2006 May 15.

Abstract

Resurgent currents are functionally crucial in sustaining the high frequency firing of cerebellar Purkinje neurons expressing Na(v)1.6 channels. Beta-scorpion toxins, such as CssIV, induce a left shift in the voltage-dependent activation of Na(v)1.2 channels by "trapping" the IIS4 voltage sensor segment. We found that the dangerous Cn2 beta-scorpion peptide induces both the left shift voltage-dependent activation and a transient resurgent current only in human Na(v)1.6 channels (among 1.1-1.7), whereas CssIV did not induce the resurgent current. Cn2 also produced both actions in mouse Purkinje cells. These findings suggest that only distinct beta-toxins produce resurgent currents. We suggest that the novel and unique selectivity of Cn2 could make it a model drug to replace deep brain stimulation of the subthalamic nucleus in patients with Parkinson disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Humans
  • Kidney
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Mice
  • Models, Molecular
  • Molecular Sequence Data
  • NAV1.6 Voltage-Gated Sodium Channel
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / drug effects
  • Nerve Tissue Proteins / physiology*
  • Protein Conformation
  • Purkinje Cells / physiology*
  • Scorpion Venoms / isolation & purification
  • Scorpion Venoms / toxicity*
  • Scorpions
  • Sodium Channels / chemistry
  • Sodium Channels / drug effects
  • Sodium Channels / physiology*
  • Tetrodotoxin / toxicity

Substances

  • NAV1.6 Voltage-Gated Sodium Channel
  • Nerve Tissue Proteins
  • SCN8A protein, human
  • Scn8a protein, mouse
  • Scorpion Venoms
  • Sodium Channels
  • Tetrodotoxin