Figure 1.

Molecular structure of NMDAR. The NMDAR is anchored in the cell membrane, and four subunits (commonly 2 GluN1 and 2 GluN2) form an NMDAR channel selective for the cations. The glycine binding site and glutamate binding site are located in the GluN1 and GluN2 subunit, respectively. When the membrane is not depolarized, even when two agonists occupy binding sites, the channel is blocked by the Mg²⁺ ion. Ketamine or other derivatives of phencyclidine can inactivate the receptor by binding to the intraductal PCP site.