GluR5 kainate receptors, seizures, and the amygdala

Michael A Rogawski, Divina Gryder, Dora Castaneda, Wayne Yonekawa, Melissa K. Banks, He Li

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

The amygdala is a critical brain region for limbic seizure activity, but the mechanisms underlying its epileptic susceptibility are obscure. Several lines of evidence implicate GluR5 (GLUK5) kainate receptors, a type of ionotropic glutamate receptor, in the amygdala's vulnerability to seizures and epileptogenesis. GluR5 mRNA is abundant in temporal lobe structures including the amygdala. Brain slice recordings indicate that GluR5 kainate receptors mediate a portion of the synaptic excitation of neurons in the rat basolateral amygdala. Whole-cell voltage-clamp studies demonstrate that GluR5 kainate receptor-mediated synaptic currents are inwardly rectifying and are likely to be calcium permeable. Prolonged activation of basolateral amygdala GluR5 kainate receptors results in enduring synaptic facilitation through a calcium-dependent process. The selective GluR5 kainate receptor agonist ATPA induces spontaneous epileptiform bursting that is sensitive to the GluR5 kainate receptor antagonist LY293558. Intra-amygdala infusion of ATPA in the rat induces limbic status epilepticus; in some animals, recurrent spontaneous seizures occur for months after the ATPA treatment. Together, these observations indicate that GluR5 kainate receptors have a unique role in triggering epileptiform activity in the amygdala and could participate in long-term plasticity mechanisms that underlie some forms of epileptogenesis. Accordingly, GluR5 kainate receptors represent a potential target for antiepileptic and antiepileptogenic drug treatments. Most antiepileptic drugs do not act through effects on glutamate receptors. However, topiramate at low concentrations causes slow inhibition of GluR5 kainate receptor-mediated synaptic currents in the basolateral amygdala, indicating that it may protect against seizures, at least in part, through suppression of GluR5 kainate receptor responses.

Original languageEnglish (US)
Pages (from-to)150-162
Number of pages13
JournalAnnals of the New York Academy of Sciences
Volume985
StatePublished - 2003
Externally publishedYes

Keywords

  • AMPA receptor
  • Amygdala
  • ATPA
  • Epilepsy
  • GluR5 kainate receptor
  • LY293558
  • Synaptic plasticity
  • Synaptic transmission
  • Topiramate

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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  • Cite this

    Rogawski, M. A., Gryder, D., Castaneda, D., Yonekawa, W., Banks, M. K., & Li, H. (2003). GluR5 kainate receptors, seizures, and the amygdala. Annals of the New York Academy of Sciences, 985, 150-162.