The interrelated lives of NMDA receptors and glycine transporters.

摘要

Most glutamate N-methyl-D-aspartic acid receptors (NMDARs) in the adultvCNS probably assemble as dimers of dimers, each one composed of an NR1 and an NR2 subunit (the developing CNS and adult motoneurons also express NR3 sub-units, but the stoichiometry with which these assemble to form functional NMDARs remains unclear). The extracellular domain of these subunits contains a region, the S1S2 core, where the interaction between ligand and receptor actually occurs (Furukawa et al. 2005). NMDAR opening, however, is not fully accomplished until other events have also taken place: not only each NR2 subunit needs to bind a glutamate molecule, but also both NR1 subunits have to bind a molecule of a co-agonist (under physiological conditions (Johnson & Ascher, 1987) or D-serine (Schell et al. 1995)). In addition, membrane depolarization is required to relieve the Mg~2+ block of the receptor.