The two subtypes of receptors are differentiated by their subunits: GluN2A-containing NMDA receptors that are mainly distributed at the synapse contribute to normal physiological functions and promote survival of neurons; GluN2B-containing NMDA receptors that are primarily found in extrasynaptic locations, mediate excitatory toxic injury caused by various noxious stimulations including cerebral ischemia, and promote neuronal death (Liu et al., 2007; Sun et al., 2015b). This evidence concerns the gene GRIN2A and brain ischemia.