Neuronal signals elicited by glutamate are processed by ionotropic and metabotropic subtypes of receptors. The ionotropic receptor group contains integral cation-specific ion channels and is further subdivided into 2 types, N-methyl-D-aspartate (NMDA) and non-NMDA receptors.
The sequence of the predicted 1,336-amino acid human NMDAR2D
protein is 95% identical to that of rat Nmdar2d. NMDAR1/NMDAR2D receptors expressed in Xenopus oocytes and mammalian cells displayed a pharmacologic and biophysical profile distinct from those of other human recombinant NMDA receptors. Northern blot analysis detected expression of a 6.0-kb transcript in an osteosarcoma cell line.