NMDA Receptor

NMDA receptor (NMDAR) ionotropic glutamate receptors support synaptogenesis, synaptic maturation, long-term plasticity, neuronal network activity, and cognition^[1]. Mechanistically, NMDARs act as glutamate-gated, calcium-permeable ion channels that mediate synaptic transmission and underpin learning and memory^[2]. Their activation requires coordinated agonist binding, with glutamate binding GluN2 and glycine or D-serine binding GluN1^[3]. In disease contexts, abnormal NMDAR-mediated signaling is associated with neurological and psychiatric disorders, while NMDAR dysfunction is implicated in seizure and ischemia models^[1][2]. Anti-NMDA receptor encephalitis further links receptor-targeting antibodies with rapidly progressive neuropsychiatric disease mechanisms and experimental models^[4]. Compared with related NMDA receptor isoforms, subunit composition creates receptor subtypes with distinct biophysical, pharmacological, and signaling properties^[5]. Therefore, GluN2A, GluN2B, GluN2C, GluN2D, and GluN3-containing receptors should be separated in experimental design when subtype-specific function, synaptic plasticity, or disease signaling is tested^[5]. For experimental applications, agonists and inhibitors provide mechanistic tools because agonists stabilize ligand-binding-domain gating arrangements, whereas competitive antagonists disrupt receptor activation^[2]. D-serine also provides a useful ligand model because it binds GluN1, interacts with GluN2A, and can inhibit NMDAR current at high concentration^[3].