Article date: 1992/1/31
PubMed ID: 1377085
Journal name: Brain research (ISSN: 0006-8993)
Kainic acid is supposed to be a specific agonist for a subclass of excitatory glutamate receptors in the vertebrate CNS. An investigation of (2 nM) [3H]kainic acid binding sites in goldfish brain, using quantitative autoradiography, has revealed evidence for two types of kainic acid receptors which differ in sensitivity to glutamic acid. L-Glutamic acid (0.1-1 mM) displaced over 95% of specific [3H]kainic acid binding elsewhere in the brain but only 10-50% in the cerebellum and cerebellar crest. These structures apparently contain [3H]kainic acid binding sites that are extremely insensitive to glutamic acid. The glutamic acid-insensitive [3H]kainic acid binding was not displaced by quisqualic acid, kynurenic acid, alpha-amino-3-hydroxy-5-methylisoxazolepropionic acid (AMPA), or N-methyl-D-aspartatic acid, but was completely displaced by the kainic acid analogue domoic acid. The data indicate that two types of high affinity binding sites for [3H]kainic acid exist in the goldfish brain: glutamic acid-sensitive and glutamic acid-insensitive. High affinity [3H]kainic acid binding may therefore not always represent binding to subsets of glutamic acid receptors.
Author List: Davis R E, Wilmot G R, Cha J H
Publication Types: Journal Article
Substances mentioned in the article: Glutamates; Ligands; Neurotoxins; Tritium; Ibotenic Acid; Glutamic Acid; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; domoic acid; Kainic Acid;
Mesh terms: Animals; Autoradiography; Binding, Competitive; Brain/metabolism; Glutamates/pharmacology; Glutamic Acid; Goldfish; Ibotenic Acid/analogs & derivatives; Kainic Acid/analogs & derivatives; Ligands; Neurotoxins/metabolism; Tissue Distribution; Tritium; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;