N-methyl-D-aspartate (n MDA) receptors are a class of ionotropic glutamate receptors. n MDA channel has been shown to be involved in long-term potentiation, an activity-dependent increase in the efficiency of synaptic transmission thought to underlie certain kinds of memory and learning. n MDA receptor channels are heteromers composed of the key receptor subunit n MDAR1 (GRIN1) and 1 or more of the 4 n MDAR2 subunits: n MDAR2A (GRIN2A), n MDAR2B (GRIN2B), n MDAR2C (GRIN2C), and n MDAR2D (GRIN2D).