An agonist at two subsets of excitatory amino acid receptors, ionotropic receptors that directly control membrane channels and metabotropic receptors that indirectly mediate calcium mobilization from intracellular stores. The compound is obtained from the seeds and fruit of Quisqualis chinensis.

An amino acid that, as the D-isomer, is the defining agonist for the NMDA receptor subtype of glutamate receptors (RECEPTORS, NMDA).