title: Stretch injury selectively enhances extrasynaptic, GluN2B-containing NMDA receptor function in cortical neurons.
abstract: Alterations in the function and expression of NMDA receptors are observed after in vivo and in vitro traumatic brain injury. We recently reported that mechanical stretch injury in cortical neurons transiently increases the contribution of NMDA receptors to network activity and results in an increase in calcium-permeable AMPA (CP-AMPA) receptor-mediated transmission 4 h postinjury (Goforth et al. 2011). Here, we evaluated changes in the function of synaptic vs. extrasynaptic GluN2B-containing NMDA receptors after injury. We also determined whether postinjury treatment with the GluN2B-selective antagonist Ro 25-6981 or memantine prevents injury-induced increases in CP-AMPA receptor activity. We found that injury increased extrasynaptic, GluN2B-containing NMDA receptor-mediated whole cell currents. In contrast, we found no differences in synaptic NMDA receptor-mediated transmission after injury. Furthermore, treatment with Ro 25-6981 or memantine after injury prevented injury-induced increases in CP-AMPA receptor-mediated activity. Together, our data suggest that increased NMDA receptor activity after injury is predominantly due to alterations in extrasynaptic, GluN2B-containing NMDA receptors and that activation of these receptors may contribute to the appearance of CP-AMPA receptors after injury.
authors.affiliation: Department of Pharmacology, The University of Michigan, Ann Arbor, Michigan 48105, USA.
authors.forename: Carrie R
authors.initials: CR
authors.lastname: Ferrario
authors.forename: Blaise O
authors.initials: BO
authors.lastname: Ndukwe
authors.forename: Jianhua
authors.initials: J
authors.lastname: Ren
authors.forename: Leslie S
authors.initials: LS
authors.lastname: Satin
authors.forename: Paulette B
authors.initials: PB
authors.lastname: Goforth
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: C121001:NR2B NMDA receptor; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate
keywords: GluN2B; NMDA receptors; cortical injury; traumatic brain injury