N-Methyl-D-Aspartic acid (NMDA) is a synthetic agonist of the NMDA receptor that mimics the binding action of the endogenous ligand glutamate. The NMDA receptor is a voltage-gated ion channel closely involved in memory, in spatial learning and perturbing the normal behavior of this receptor system with NMDA exposure has facilitated elucidation of NMDA receptor-mediated activities.

NMDA is a glutamate-like excitatory substance and is a particularly potent excitant. NMDA binds to NMDA-receptor and interacts with it. This interaction causes a conformational change in the receptor or associated membrane molecules, which opened pores to allow extracellular sodium ions to flow down their electrochemical gradient and depolarise the cell. However, NMDA is proved to be a poor substrate for the uptake transporters, suggesting that the excitatory effect could not be an indirect consequence of glutamate uptake. Besides that, NMDA is found to increase intracellular calcium and release arachidonic acid, both of which generate oxygen radicals, subsequently inducing neuronal death.