Medial vestibular nucleus in the guinea-pig. II. Ionic basis of the intrinsic membrane properties in brainstem slices

Exp Brain Res. 1991;84(2):426-33. doi: 10.1007/BF00231465.

Abstract

In the preceding paper, medial vestibular nuclei neurones (MVNn) were shown to belong to two main classes, A MVNn and B MVNn, depending on their membrane properties in brainstem slices. In the following study we attempted to confirm this segregation by studying some of the ionic conductances that these cells are endowed with. Type A MVNn demonstrated small high threshold calcium spikes that could be potentiated by barium, a 4-AP resistant A-like conductance and a calcium-dependent afterhyperpolarization. Type B MVNn, in contrast, had large high threshold calcium spikes and prolonged calcium-dependent plateau potentials. In addition, they had a calcium-dependent afterhyperpolarization as well as a subthreshold persistent sodium conductance. A subpopulation of B MVNn had also low threshold calcium spikes that gave them bursting properties. These data confirm the segregation of MVN neurones into two main classes and will be discussed with respect to the firing characteristics of vestibular neurones in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminopyridine / pharmacology
  • Action Potentials / drug effects
  • Animals
  • Brain Stem / physiology*
  • Cadmium / pharmacology
  • Calcium Channels / drug effects
  • Calcium Channels / physiology
  • Cell Membrane / drug effects
  • Cell Membrane / physiology
  • Cobalt / pharmacology
  • Electric Conductivity / drug effects
  • Evoked Potentials / drug effects
  • Guinea Pigs
  • In Vitro Techniques
  • Neurons / drug effects
  • Neurons / physiology*
  • Potassium Channels / drug effects
  • Potassium Channels / physiology
  • Sodium Channels / drug effects
  • Sodium Channels / physiology
  • Tetraethylammonium
  • Tetraethylammonium Compounds / pharmacology
  • Tetrodotoxin / pharmacology
  • Vestibular Nuclei / drug effects
  • Vestibular Nuclei / physiology*

Substances

  • Calcium Channels
  • Potassium Channels
  • Sodium Channels
  • Tetraethylammonium Compounds
  • Cadmium
  • Cobalt
  • Tetrodotoxin
  • Tetraethylammonium
  • 4-Aminopyridine