Extrasynaptic NMDA receptors are glutamate-gated neurotransmitter receptors that are localized to non-synaptic sites on the neuron al cell surface .[ 1] [ 2] In contrast to synaptic NMDA receptors that promote acquired neuroprotection and synaptic plasticity , extrasynaptic NMDA receptors are coupled to activation of death-signaling pathways.[ 3] Extrasynaptic NMDA receptors are responsible for initiating excitotoxicity and have been implicated in the etiology of neurodegenerative diseases , including stroke , Huntington’s disease , Alzheimer’s disease , and amyotrophic lateral sclerosis (ALS).[ 4] [ 5] [ 6] [ 7] [ 8]
Extrasynaptic NMDA receptors form a death signaling complex with the transient receptor potential cation channel subfamily M member 4 (TRPM4). The NMDAR/TRPM4 complex is considered central to glutamate excitotoxicity.[ 9] NMDAR/TRPM4 interaction interface inhibitors (also known as 'interface inhibitors') disrupt the NMDAR/TRPM4 complex thereby detoxifying extrasynaptic NMDA receptors. In mouse disease models, interface inhibitors protect against stroke induced brain damage and retinal ganglion cell degeneration.[ 10] [ 11]
^ Tovar, Kenneth R.; Westbrook, Gary L. (2002-04-11). "Mobile NMDA receptors at hippocampal synapses" . Neuron . 34 (2): 255– 264. doi :10.1016/s0896-6273(02)00658-x . ISSN 0896-6273 . PMID 11970867 .
^ Petralia, R. S.; Wang, Y. X.; Hua, F.; Yi, Z.; Zhou, A.; Ge, L.; Stephenson, F. A.; Wenthold, R. J. (2010-04-28). "Organization of NMDA receptors at extrasynaptic locations" . Neuroscience . 167 (1): 68– 87. doi :10.1016/j.neuroscience.2010.01.022 . ISSN 1873-7544 . PMC 2840201 . PMID 20096331 .
^ Hardingham, G. E.; Fukunaga, Y.; Bading, H. (2002-05-01). "Extrasynaptic NMDARs oppose synaptic NMDARs by triggering CREB shut-off and cell death pathways". Nature Neuroscience . 5 (5): 405– 414. doi :10.1038/nn835 . ISSN 1097-6256 . PMID 11953750 . S2CID 659716 .
^ Okamoto, Shu-ichi; Pouladi, Mahmoud A.; Talantova, Maria; Yao, Dongdong; Xia, Peng; Ehrnhoefer, Dagmar E.; Zaidi, Rameez; Clemente, Arjay; Kaul, Marcus (2009-12-01). "Balance between synaptic versus extrasynaptic NMDA receptor activity influences inclusions and neurotoxicity of mutant huntingtin" . Nature Medicine . 15 (12): 1407– 1413. doi :10.1038/nm.2056 . ISSN 1546-170X . PMC 2789858 . PMID 19915593 .
^ Milnerwood, Austen J.; Gladding, Clare M.; Pouladi, Mahmoud A.; Kaufman, Alexandra M.; Hines, Rochelle M.; Boyd, Jamie D.; Ko, Rebecca W. Y.; Vasuta, Oana C.; Graham, Rona K. (2010-01-28). "Early increase in extrasynaptic NMDA receptor signaling and expression contributes to phenotype onset in Huntington's disease mice" . Neuron . 65 (2): 178– 190. doi :10.1016/j.neuron.2010.01.008 . ISSN 1097-4199 . PMID 20152125 .
^ Talantova, Maria; Sanz-Blasco, Sara; Zhang, Xiaofei; Xia, Peng; Akhtar, Mohd Waseem; Okamoto, Shu-ichi; Dziewczapolski, Gustavo; Nakamura, Tomohiro; Cao, Gang (2013-07-02). "Aβ induces astrocytic glutamate release, extrasynaptic NMDA receptor activation, and synaptic loss" . Proceedings of the National Academy of Sciences of the United States of America . 110 (27): E2518–2527. Bibcode :2013PNAS..110E2518T . doi :10.1073/pnas.1306832110 . ISSN 1091-6490 . PMC 3704025 . PMID 23776240 .
^ Hardingham, Giles E.; Bading, Hilmar (2010-10-01). "Synaptic versus extrasynaptic NMDA receptor signalling: implications for neurodegenerative disorders" . Nature Reviews. Neuroscience . 11 (10): 682– 696. doi :10.1038/nrn2911 . ISSN 1471-0048 . PMC 2948541 . PMID 20842175 .
^ Parsons, Matthew P.; Raymond, Lynn A. (2014-04-16). "Extrasynaptic NMDA receptor involvement in central nervous system disorders" . Neuron . 82 (2): 279– 293. doi :10.1016/j.neuron.2014.03.030 . ISSN 1097-4199 . PMID 24742457 .
^ Yan, Jing; Bengtson, C. Peter; Buchthal, Bettina; Hagenston, Anna M.; Bading, Hilmar (9 October 2020). "Coupling of NMDA receptors and TRPM4 guides discovery of unconventional neuroprotectants" . Science . 370 (6513): eaay3302. doi :10.1126/science.aay3302 . ISSN 1095-9203 . PMID 33033186 . S2CID 222210921 .
^ Yan, Jing; Bengtson, C. Peter; Buchthal, Bettina; Hagenston, Anna M.; Bading, Hilmar (9 October 2020). "Coupling of NMDA receptors and TRPM4 guides discovery of unconventional neuroprotectants" . Science . 370 (6513): eaay3302. doi :10.1126/science.aay3302 . ISSN 1095-9203 . PMID 33033186 . S2CID 222210921 .
^ "New Class of Highly Effective Inhibitors Protects against Neurodegeneration – Heidelberg University" . www.uni-heidelberg.de . Retrieved 2020-10-29 .