l-[H]Glutamate binds to kainate-, NMDA- and AMPA-sensitive binding sites: an autoradiographic analysis

The anatomical distribution ofl-³H]glutamate binding sites was determined in the presence of various glutamate analogues using quantitative autoradiography. The binding ofl-³H]glutamate is accounted for the presence of 3 distinct binding sites when measured in the absence of Ca²⁺, Cl⁻ and Na⁺ ions. The anatomical distribution and pharmacological specificity of these binding sites correspond to that reported for the 3 excitatory amino acid binding sites selectively labeled byd-³H]2-amino-5-phosphonopentanoate (d-³H]AP5), ³H]kainate (³H]KA) and ³H]α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (³H]AMPA) which are thought to be selective ligands for the N-methyl-d-aspartate (NMDA), KA and quisqualate (QA) receptors, respectively.