L-689502 is primarily used in research settings as a potent and selective antagonist for the NMDA receptor, specifically targeting the glycine site. This makes it a valuable tool in studying the role of NMDA receptors in various neurological processes, such as synaptic plasticity, learning, and memory. Researchers also utilize it to investigate conditions like neurodegeneration, stroke, and epilepsy, where NMDA receptor overactivation is implicated. Additionally, L-689502 has been employed in preclinical studies to explore potential therapeutic strategies for neurological disorders by modulating NMDA receptor activity. Its specificity allows for detailed mechanistic insights into receptor function and its contribution to brain physiology and pathology.