Brain NMDA receptor subunits

Suzuki, T. and Okumura-Noji, K. NMDA receptor subunits e1 (NR2A) and e2 (NR2B) are substrates for Fyn in the postsynaptic density fraction isolated from the rat brain, Biochem. Biophys. Res. Comm. 1995, 216, 582-588. 

Structure and Distribution of NMDA Receptor Subunits in Brain... 

Another mechanism of synaptic dysfunction in AD may involve amyloid ft peptide (Aft a 40 to 42 amino acid peptide). A marked increase in Aft levels occurs in brain tissue from AD patients. A ft inhibits glutamatergic neurotransmission and reduces synaptic plasticity (Snyder et al., 2005). Treatment of cortical neuronal cultures with Aft facilitates endocytosis of NMDA receptor. Aft-mediated endo-cytosis of NMDA receptor requires the a-1 nicotinic receptor, protein phosphatase 2B, and the tyrosine phosphatase STEP. Dephosphorylation of the NMDA receptor subunit NR2B at Tyrl472 correlates with receptor endocytosis. The addition of a y-secretase inhibitor not only reduces Aft but also restores surface expression of NMDA receptors, suggesting that A plays an important role in the regulation of NMDA and AMPA receptor trafficking (Snyder et al., 2005 Morishita et al., 2005). 

Okamato S-i, Sherman K, Bai G, Lipton SA. 2002. Effect of the ubiquitous transcription factors, SP1 and MAZ, on NMDA receptor subunit type 1 (NR1) expression during neuronal differentiation. Mol Brain Res 107 89-96. 

Fig. 5. The expression of the NMDA receptor subunit mRNAs (NRl, NR2A-NR2D) in the adult rat brain (X-ray film autoradiographs, horizontal sections) (Monyer et al., 1992, 1994).

Bahn S, Wisden W (1997) A map of non-NMDA receptor subunit expression in the vertebrate brain derived from in situ hybridization histochemistry. In Monaghan DT, Wenthold RJ (Eds), The Ionotropic Glutamate Receptors. Totowa, NJ Humana Press Inc., pp 149-187. 

Ishiyama G, Lopez I, Ishiyama A (1999) Subcellular immunolocalization of NMDA receptor subunit NR-1 in the chinchilla vestibular periphery. Brain Res 857 270-276. 

Boyer, P.A., Skolnick, R, and Fossom, L.H. 1998. Chronic administration of imipramine and dta-lopram alters the expression of NMDA receptor subunit mRNAs in mouse brain. A quantitative in situ hybridization study. J. Mol. Neurosci. 10 219-233. 

While there are some reports of increased NMDA and non-NMDA receptor number in various cortical regions of schizophrenics including the prefrontal cortex, there are also indications of impaired glutamate innervation, such as reduction in its neuronal uptake sites (Ishimaru, Kurumaji and Torn 1994). Also it has been found that levels of the mRNA for the NRI subunit of the NMDA receptor in the hippocampus and its D-aspartate binding sites in the temporal cortex are both reduced more on the left than right side in schizophrenic brain. This is another indication of greater malfunction on the left side of the brain and the possibility that some schizophrenic symptoms arise from an imbalance between cross-cortical activity. 

White, T. L. and Youngentob, S. L. The effect of NMDA-NR2B receptor subunit over-expression on olfactory memory task performance in the mouse. Brain Res. 1021,1-7, 2004. 

A post-mortem study on the brains of alcohoUcs showed a modest increased binding for [3H]glutamate and [3H]CGP-39653—a competitive NMDA receptor antagonist (Freund and Anderson 1996). In humans with a history of alcohol abuse, an increase in immunoreactivity toward AMPA GluR2 and GluR3 subunits was also found (Breese et al. 1995). In rodents lacking functional... 

Ikeda, K., Araki, K., Takayama, C., Inoue, Y., Yagi, T., Aizawa, S., Mishina, M. Reduced spontaneous activity of mice defective in the e4 subunit of the NMDA receptor channel, Brain Res. Mol. Brain Res. 1995, 33, 61-71. 

Furuyama, T., Kiyama, H., Sato, K., Park, H.T., Maeno, H., Takagi, H., Tohyama, M. Region-specific expression of subunits of ionotropic glutamate receptors (AMPA-type, KA-type, and NMDA receptors) in the rat spinal cord with special reference to nociception, Brain Res. Mol. Brain Res. 1993, 18, 141-151. 

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