Physiological role of dendrotoxin-sensitive K+ channels in the rat cerebellar Purkinje neurons

Physiol Res. 2007;56(6):807-813. doi: 10.33549/physiolres.931041. Epub 2006 Nov 6.

Abstract

To understand the contribution of potassium (K+) channels, particularly alpha-dendrotoxin (D-type)-sensitive K+ channels (Kv.1, Kv1.2 or Kv1.6 subunits), to the generation of neuronal spike output we must have detailed information of the functional role of these channels in the neuronal membrane. Conventional intracellular recording methods in current clamp mode were used to identify the role of alpha-dendrotoxin (alpha-DTX)-sensitive K+ channel currents in shaping the spike output and modulation of neuronal properties of cerebellar Purkinje neurons (PCs) in slices. Addition of alpha-DTX revealed that D-type K+ channels play an important role in the shaping of Purkinje neuronal firing behavior. Repetitive firing capability of PCs was increased following exposure to artificial cerebrospinal fluid (aCSF) containing alpha-DTX, so that in response to the injection of 0.6 nA depolarizing current pulse of 600 ms, the number of action potentials insignificantly increased from 15 in the presence of 4-AP to 29 action potentials per second after application of DTX following pretreatment with 4-AP. These results indicate that D-type K+ channels (Kv.1, Kv1.2 or Kv1.6 subunits) may contribute to the spike frequency adaptation in PCs. Our findings suggest that the activation of voltage-dependent K+ channels (D and A types) markedly affect the firing pattern of PCs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminopyridine / pharmacology
  • Action Potentials / physiology
  • Animals
  • Elapid Venoms / pharmacology*
  • Electrophysiology
  • Kv1.2 Potassium Channel / drug effects
  • Kv1.2 Potassium Channel / physiology
  • Kv1.6 Potassium Channel / drug effects
  • Kv1.6 Potassium Channel / physiology
  • Male
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Potassium Channel Blockers / pharmacology*
  • Purkinje Cells / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Shaker Superfamily of Potassium Channels / drug effects
  • Shaker Superfamily of Potassium Channels / physiology*

Substances

  • Elapid Venoms
  • Kv1.2 Potassium Channel
  • Kv1.6 Potassium Channel
  • Potassium Channel Blockers
  • Shaker Superfamily of Potassium Channels
  • dendrotoxin
  • 4-Aminopyridine