GluR5 kainate receptor mediated synaptic transmission in rat basolateral amygdala in vitro

Neuropharmacology. Oct-Nov 1998;37(10-11):1279-86. doi: 10.1016/s0028-3908(98)00109-9.

Abstract

A non-NMDA and non-AMPA receptor mediated excitatory synaptic response was identified in intracellularly recorded basolateral amygdala (BLA) neurons in an in vitro slice preparation. Synaptic potentials were evoked by stimulation of either the external capsule (EC) or basal amygdala (BA). NMDA and GABA(A) receptors were blocked by inclusion of 100 microM (+/-)-2-amino-5-phosphonopentanoic acid and 10 microM bicuculline in the perfusion solution. The AMPA receptor-selective allosteric antagonists GYKI 52466 (50 microM) and GYKI 53655 (50 microM) partially suppressed depolarizing synaptic responses evoked by single shock EC stimulation, but fully blocked synaptic responses evoked by BA stimulation. In recordings carried out in the presence of the AMPA receptor antagonists, EC stimulation with pulse trains (5-8 pulses at 50-100 Hz) evoked a large increase in the amplitude of synaptic responses. The AMPA receptor-independent component of the train-induced synaptic response had a null potential near 0 mV. Such AMPA receptor-independent, train-evoked synaptic responses were largely blocked by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (20 microM; 85 +/- 4%). In addition, the responses were blocked by the GluR5-selective kainate receptor antagonist LY293558 (10 microM; 95 +/- 2%). These results indicate that a component of the EC (but not the BA) synaptic response is mediated by kainate receptors containing the GluR5 subunit.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
  • Amygdala / drug effects
  • Amygdala / physiology*
  • Animals
  • Anti-Anxiety Agents / pharmacology
  • Benzodiazepines*
  • Excitatory Amino Acid Antagonists / pharmacology
  • Isoquinolines / pharmacology
  • Male
  • Patch-Clamp Techniques
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, AMPA / antagonists & inhibitors
  • Receptors, Kainic Acid / drug effects
  • Receptors, Kainic Acid / physiology*
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology*
  • Tetrazoles / pharmacology

Substances

  • Anti-Anxiety Agents
  • Excitatory Amino Acid Antagonists
  • Gluk1 kainate receptor
  • Isoquinolines
  • Receptors, AMPA
  • Receptors, Kainic Acid
  • Tetrazoles
  • GYKI 52466
  • Benzodiazepines
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • tezampanel