L-689560（Cat No.:M114679）is a potent and selective competitive antagonist of the glycine co-agonist site on NMDA (N-methyl-D-aspartate) receptors. By blocking this modulatory site, it inhibits NMDA receptor–mediated excitatory neurotransmission without directly affecting glutamate binding. This makes L-689560 a useful pharmacological tool for studying NMDA receptor function, synaptic plasticity, learning, and memory. It has also been explored in models of excitotoxicity, neurodegeneration, and psychiatric disorders where NMDA receptor dysregulation plays a role. L-689560 supports neuroscience research into therapeutic strategies targeting glutamatergic signaling pathways.