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Distribution and Ontogeny of 1 S ,3 R ‐1‐Aminocyclopentane‐1,3‐Dicarboxylic Acid‐Sensitive and Quisqualate‐Insensitive [ 3 H]Glutamate Binding Sites in the Rat Brain
Author(s) -
Wright Rebecca A.,
McDonald John W.,
Schoepp Darryle D.
Publication year - 1994
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1994.63030938.x
Subject(s) - metabotropic glutamate receptor , glutamate receptor , biology , metabotropic glutamate receptor 5 , forebrain , metabotropic glutamate receptor 1 , metabotropic receptor , metabotropic glutamate receptor 6 , metabotropic glutamate receptor 2 , metabotropic glutamate receptor 7 , biophysics , biochemistry , neuroscience , receptor , central nervous system
Abstract: Displacement of [ 3 H]glutamate by 1 S ,3 R ‐1‐aminocyclopentane‐1,3‐dicarboxylic acid and quisqualate (in the presence of saturating concentrations of ionotropic glutamate receptor agonists) was used to characterize optimal ionic conditions, distribution, and the ontogeny of glutamate receptor binding sites in rat brain. Using rat forebrain membranes or receptor autoradiography, optimal 1 S ,3 R ‐1‐aminocyclopentane‐1,3‐dicarboxylic acid‐sensitive [ 3 H]glutamate binding was found in the presence of 100 m M bromide ions and in the absence of calcium ions. Under these conditions, [ 3 H]glutamate binding was relatively quisqualate insensitive. In regions of the neonatal (11‐day‐old) and adult rat brain, this [ 3 H]glutamate binding was highest in forebrain (striatum, cerebral cortex, and hippocampus) and hypothalamus/midbrain but was lower in the cerebellum, olfactory bulb, and pons/medulla regions. 1 S ,3 R ‐1‐aminocyclopentane‐1,3‐dicarboxylic acid‐sensitive and quisqualate‐insensitive [ 3 H]glutamate binding was present in the rat forebrain at 1 day of age and gradually increased more than twofold by day 50 (adult). Thus, in the presence of bromide ions and in the absence of calcium ions, [ 3 H]glutamate labels a subpopulation of metabotropic glutamate receptors that are sensitive to 1 S ,3 R ‐1‐aminocyclopentane‐1,3‐dicarboxylic acid but insensitive to quisqualate. Expression of [ 3 H]glutamate binding under these conditions was both regionally and developmentally regulated in rat brain, suggesting that [ 3 H]glutamate is labeling a distinct population of metabotropic glutamate receptors.