Heterocyclic modulators of the NMDA receptor.

The design of new heterocyclic derivatives as modulatory agents at EAA receptors is described. In particular, the potent and selective activity at the NMDA receptor of trans-4-hydroxypipecolic acid-4-sulfate, as well as the neuroprotective properties of substituted thiokynurenates, a new class of competitive antagonists at the glycine site of the NMDA receptor complex, are reported.