Glycine site of the N-methyl-D-aspartate receptor (NMDA glycine site)

The glycine site of the N-methyl-D-aspartate (NMDA) receptor is a critical modulatory site located on the GluN1 and sometimes GluN3 subunits of this glutamate-gated ionotropic receptor[1][6]. This site must be occupied by glycine or D-serine for the NMDA receptor channel to open, in concert with glutamate binding to the GluN2 subunit, enabling ion flow through the receptor[4][6]. The NMDA receptor itself is a tetrameric ligand-gated ion channel composed typically of two GluN1 and two GluN2 (or sometimes GluN3) subunits[1][2][3]. The glycine-binding (co-agonist) site confers essential roles in synaptic plasticity, learning, memory, and neurodevelopment, but its dysregulation is implicated in schizophrenia, neurodegeneration, epilepsy, and other CNS disorders[5][6][7]. Drugs targeting the glycine site have been explored for both potentiating and inhibiting NMDA receptor function for therapeutic purposes. Modulation of this site remains an active area of CNS drug development given its central role in excitatory neurotransmission and disease[6][7].

Other names

Glycine modulatory site of the NMDA receptorGlycine-binding site of NMDA receptorGlycine co-agonist site of NMDA receptor

Agonists: potentiate receptor channel function by binding to the glycine site (e.g., glycine, D-serine)[6]. Partial agonists: bind and evoke partial channel activity (e.g., D-cycloserine)[6]. Antagonists: bind the glycine site and inhibit receptor activity (e.g., 7-chlorokynurenic acid, L-701,324)[7]. Indirect modulation via inhibition of glycine reuptake (e.g., bitopertin increases synaptic glycine concentration)[6].