Synthesis, radiolabelling and biological characterization of (D)-7-iodo-N-(1-phosphonoethyl)-5-aminomethylquinoxaline-2,3-dione, a glycine-binding site antagonist of NMDA receptors

(D)-7-Iodo-N-(1-phosphonoethyl)-5-aminomethylquinoxaline-2,3-dione (I-PAMQX ), is a potent, in vivo active antagonist acting at the glycine binding sit e of the NMDA receptor complex. Radioiodinated [I-131]I-PAMQX was prepared with good yields and high specific activity from its 7-bromo analogue. Biod istribution studies of [I-131]I-PAMQX in mice showed a relatively slow clea rance from the blood. The uptake of radioactivity was highest in the kidney s, moderate in the heart, lung, liver and bones, and low in the brain. (C) 1999 Elsevier Science Ltd. All rights reserved.