Kainate activates Ca(2+)-permeable glutamate receptors and blocks voltage-gated K+ currents in glial cells of mouse hippocampal slices

Pflugers Arch. 1994 Feb;426(3-4):310-9. doi: 10.1007/BF00374787.


Glial cells in the CA1 stratum radiatum of the hippocampus of 9- to 12-day-old mice show intrinsic responses to glutamate due to the activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)/kainate receptors. In the present study we have focused on a subpopulation of the hippocampal glial cells, the "complex" cells, characterized by voltage-gated Na+ and K+ channels. Activation of glutamate receptors in these cells led to two types of responses, the activation of a cationic conductance, and a longer-lasting blockade of voltage-gated K+ channels. In particular, the transient (inactivating) component of the outwardly rectifying K+ current was diminished by kainate. Concomitantly, as described in Bergmann glial cells, kainate also elevated cytosolic Ca2+. This increase was due to an influx via the glutamate receptor itself. In contrast to Bergmann glial cells, the cytosolic Ca2+ increase was not a link to the K+ channel blockade, since the blockade occurred in the absence of the Ca2+ signal and, vice versa, an increase in cytosolic Ca2+ induced by ionomycin did not block the transient K+ current. We conclude that glutamate receptor activation leads to complex and variable changes in different types of glial cells; the functional importance of these changes is as yet unresolved.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biotransformation / drug effects
  • Calcium / metabolism
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism*
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Electrodes
  • Electrophysiology
  • Flow Cytometry
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Hippocampus / metabolism*
  • In Vitro Techniques
  • Ion Channel Gating / drug effects*
  • Kainic Acid / pharmacology*
  • Mice
  • Neuroglia / drug effects
  • Neuroglia / metabolism*
  • Potassium Channels / drug effects
  • Potassium Channels / metabolism*
  • Receptors, AMPA / drug effects
  • Receptors, Glutamate / drug effects*
  • Sodium Channels / drug effects
  • Sodium Channels / metabolism


  • Calcium Channels
  • Potassium Channels
  • Receptors, AMPA
  • Receptors, Glutamate
  • Sodium Channels
  • Kainic Acid
  • Calcium