SYNTHESIS OF TRITIATED -2-AMINO-2-(3-HYDROXY-5-METHYLISOXAZOL-4-YL)ACETIC ACID (AMAA), A POTENT AND SELECTIVE NMDA AGONIST

-2-Amino-2-(3-hydroxy-5-methylisoxazol-4-yl)acetic acid (AMAA) is a po tent and selective agonist at the NMDA subgroup of excitatory amino ac id receptors. To probe its interaction with these receptors we have de veloped a synthesis of [H-3]AMAA. Bromination of a protected form of A MAA with NBS followed by hydrogenolysis with tritium gas in the presen ce of Pd/C and subsequent deprotection gave [H-3]AMAA with a specific activity of 25 Ci/mmol. Attempts to develop a receptor binding assay b ased on rat brain homogenates and using [H-3]AMAA as radioligand for t he NMDA receptors have not been successful.