Characterization of [(3)H]glutamate binding sites on frozen sections from rat adrenal

Some biochemical characteristics of [(3)H]glutamate (Glu) binding sites on frozen sections from the rat adrenal glands were studied. Adrenal frozen sections exhibited stereo-selective, saturable and temperature-dependent binding of [(3)H]Glu. An agonist for one of the subclasses of central Glu receptors, quisqualic acid (QA), elicited a significant inhibition of the binding, whereas neither N-methyl-d-aspartic acid nor kainic acid, agonists for other subclasses of the receptors, had such a significant effect on the binding at the concentration range similar to QA. In vitro addition of sodium acetate (100 mM) resulted in a significant inhibition of [(3)H]Glu binding to frozen sections of the rat adrenal glands. It thus appears that there exist QA-sensitive binding sites of [(3)H]Glu in the rat adrenal glands which exhibit pharmacological characteristics distinctly different from those in the brain.