Overview
- Peptide (C)NTHEKRIYQSNMLNR, corresponding to amino acid residues 323-337 of rat NMDAR2B (Accession Q00960). Extracellular, N-terminus.
- Rat dorsal root ganglion (DRG) sections (frozen), (1:50). Mouse brain sections (1:60).
- Expression of NMDAR2B (NR2B) in rat DRGImmunohistochemical staining of rat dorsal root ganglia (DRG) frozen sections using Anti-NMDAR2B (GluN2B) (extracellular)-ATTO Fluor-594 Antibody (#AGC-003-AR), (red), (1:50). Staining is present in neuronal cell bodies. Hoechst 33342 is used as the counterstain (blue).
The NMDA receptors are members of the glutamate receptor family of ion channels that also include the AMPA and Kainate receptors.
The NMDA receptors are encoded by seven genes: one NMDAR1 (or NR1) subunit, four NR2 (NR2A-NR2D) and two NR3 (NR3A-NR3B) subunits. The functional NMDA receptor appears to be a heterotetramer composed of two NMDAR1 and two NMDAR2 subunits. Whereas the NMDAR2 subunits that assemble with the NMDAR1 subunit can be either of the same kind (i.e. two NMDAR2A subunits) or different (one NMDAR2A with one NMDAR2B). NMDAR3 subunits can substitute the NMDAR2 subunits in their complex with the NMDAR1 subunit.
The NMDAR is unique among ligand-gated ion channels in that it requires the simultaneous binding of two obligatory agonists: glycine and glutamate that bind to the NMDAR1 and NMDAR2 binding sites respectively. Another unique characteristic of the NMDA receptors is their dependence on membrane potential. At resting membrane potentials the channels are blocked by extracellular Mg2+. Neuronal depolarization relieves the Mg2+ blockage and allows ion influx into the cells. NMDA receptors are strongly selective for Ca2+ influx differing from the other glutamate receptor ion channels that are non-selective cation channels.
Ca2+ entry through the NMDAR regulates numerous downstream signaling pathways including long term potentiation (a molecular model of memory) and synaptic plasticity that may underlie learning. In addition, the NMDA receptors have been implicated in a variety of neurological disorders including epilepsy, ischemic brain damage, Parkinson’s and Alzheimer’s diseases.
NMDA receptors expression and function are modulated by a variety of factors including receptor trafficking to the synapses and internalization as well as phosphorylation and interaction with other intracellular proteins.
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Multiplex staining of PSD-95 and GluN2B in rat brainImmunohistochemical staining of perfusion-fixed frozen rat parietal cortex sections using Anti-PSD-95 Antibody (#APZ-009), (1:400) and Anti-NMDAR2B (GluN2B) (extracellular)-ATTO Fluor-594 Antibody (#AGC-003-AR), (1:60). A. PSD-95 staining (green). B. The same sections were stained for GluN2B (red). C. Merge of the two images shows several cells expressing both proteins (arrows point to several examples). Nuclei are stained with DAPI (blue).