Kynurenic acid distinguishes kainate and quisqualate receptors in the vertebrate retina

Paul A. Coleman, Steven C. Massey, Robert F. Miller

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

Excitatory amino acid receptors (EAARs) underlie major synaptic pathways in the brain, retina and spinal cord. Several subclasses of EAARs have been proposed, based on pharmacological studies using a variety of agonists and antagonists. Kynurenic acid (Kyn), a metabolite of tryptophan, has been recently proposed as a potent EAAR antagonist. In this report, we show that Kyn can be used to separate two distinct classes of EAAR in the vertebrate retina: it blocks kainic acid (KA) responses but has minimal effects on responses mediated by quisqualate (QQ). At concentrations which block the KA responses, Kyn also blocks the light-evoked synaptic responses of all types of third-order neurons in the retina. These results suggest that KA receptors are the major receptor subtypes which underlie synaptic transmission and that QQ receptors are minimally utilized by light-activated pathways under the conditions of our experiments.

Original languageEnglish (US)
Pages (from-to)172-175
Number of pages4
JournalBrain Research
Volume381
Issue number1
DOIs
StatePublished - Aug 27 1986

Keywords

  • acidic amino acid
  • antagonist
  • kainic acid
  • kynurenic acid
  • quisqualate
  • retina

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