The N-Methyl-D-Aspartate (NMDA) receptor complex is comprised of 2 types of subunits, NR1 and NR2. Only one type of NR1 subunits has yet been identified while four distinct subunits have been identified for the NR2 receptor, NR2A, NR2B, NR2C, and NR2D. While the NR2 subunits are not functional alone, they combine with the NR1 subunit to produce a variety of different receptor types. A number have studies have also shown that the functional properties of the receptors complexes formed by the NR1 and NR2 subunits are largely determined by the NR2 components of the complex. NMDA receptors are post-synaptic and play important roles in plasticity in the developing and mature central nervous system (CNS). Agonists and antagonists of NMDA receptors have been proposed to be of therapeutic benefit in a number of CNS disorders, including stroke, head injury, epilepsy, pain, and Alzheimer′s disease.
