N-methyl-D-aspartate receptors (NMDARs) are ligand-gated ionotropic glutamate receptors that mediate excitatory synaptic transmission and play important roles in many aspects of nervous system function including: synaptic plasticity; learning and memory; neuronal development and circuit formation. NMDARs have been implicated in various neuronal disorders. NMDARs are heteromers consisting of an obligate NR1 subunit and most commonly one or two kinds of NR2 subunits or occasionally NR3 subunits.

NR2B is the predominant subunit found in the postnatal brain, however over time the number of NRA2 subunits increase and eventually outnumber NR2B subunits in a process known as the NR2B-NR2A developmental switch. The greater ratios of the NR2B subunit in post-natal brains leads to NMDA receptors which remain open longer compared to those with more NR2A subunits, this may be related to the greater memory abilities in the immediate postnatal period compared to late in life. NR2B improves synaptic plasticity and memory when over-expressed in neurones.

The involvement of NMDAR in the central nervous system (CNS) has become a focus area for neurodegenerative diseases such as Alzheimer’s disease, epilepsy and ischemic neuronal cell death.