TY - JOUR
T1 - MK-801 upregulates NR2A protein levels and induces functional recovery of the ipsilateral hemidiaphragm following acute C2 hemisection in adult rats
AU - Alilain, Warren J.
AU - Goshgarian, Harry G.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2007
Y1 - 2007
N2 - Background: C2 hemisection results in paralysis of the ipsilateral hemidiaphragm. Recent data indicate that an upregulation of the N-methyl-D-aspartate (NMDA) receptor 2A subunit following chronic C2 hemisection is associated with spontaneous hemidiaphragmatic recovery following injury. MK-801, an antagonist of the NMDA receptor, upregulates the NR2A subunit in neonatal rats. Hypothesis: We hypothesized that administration of MK-801 to adult, acute C2-hemisected rats would result in an increase of NR2A in the spinal cord. Furthermore, we hypothesized that upregulation of NR2A would be associated with recovery of the ipsilateral hemidiaphragm as in the chronic studies. Design: To develop a dose-response curve, adult rats were treated with varying doses of MK-801 and their spinal cords harvested and assessed for NR2A as well as AMPA GluR1 and GluR2 subunit protein levels. In the second part of this study, C2-hemisected animals received MK-801. Following treatment, the animals were assessed for recovery of the hemidiaphragm through electromyographic recordings and their spinal cords assessed for NR2A, GluR1, and GluR2. Results: Treatment with MK-801 leads to an increase of the NR2A subunit in the spinal cords of adult noninjured rats. There were no changes in the expression of GluR1 and GluR2 in these animals. Administration of MK-801 to C2-hemisected rats resulted in recovery of the ipsilateral hemidiaphragm, an increase of NR2A, and a decrease of GluR2. Conclusion: Our findings strengthen the evidence that the NR2A subunit plays a substantial role in mediating recovery of the paralyzed hemidiaphragm following C2 spinal cord hemisection.
AB - Background: C2 hemisection results in paralysis of the ipsilateral hemidiaphragm. Recent data indicate that an upregulation of the N-methyl-D-aspartate (NMDA) receptor 2A subunit following chronic C2 hemisection is associated with spontaneous hemidiaphragmatic recovery following injury. MK-801, an antagonist of the NMDA receptor, upregulates the NR2A subunit in neonatal rats. Hypothesis: We hypothesized that administration of MK-801 to adult, acute C2-hemisected rats would result in an increase of NR2A in the spinal cord. Furthermore, we hypothesized that upregulation of NR2A would be associated with recovery of the ipsilateral hemidiaphragm as in the chronic studies. Design: To develop a dose-response curve, adult rats were treated with varying doses of MK-801 and their spinal cords harvested and assessed for NR2A as well as AMPA GluR1 and GluR2 subunit protein levels. In the second part of this study, C2-hemisected animals received MK-801. Following treatment, the animals were assessed for recovery of the hemidiaphragm through electromyographic recordings and their spinal cords assessed for NR2A, GluR1, and GluR2. Results: Treatment with MK-801 leads to an increase of the NR2A subunit in the spinal cords of adult noninjured rats. There were no changes in the expression of GluR1 and GluR2 in these animals. Administration of MK-801 to C2-hemisected rats resulted in recovery of the ipsilateral hemidiaphragm, an increase of NR2A, and a decrease of GluR2. Conclusion: Our findings strengthen the evidence that the NR2A subunit plays a substantial role in mediating recovery of the paralyzed hemidiaphragm following C2 spinal cord hemisection.
KW - C2 hemisection
KW - Long-term potentiation
KW - MK-801
KW - Motor recovery
KW - N-methyl-D-aspartate (NMDA)
KW - NMDA-receptor antagonist
KW - Phrenic nucleus
KW - Plasticity
KW - Spinal cord injuries
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U2 - 10.1080/10790268.2007.11753950
DO - 10.1080/10790268.2007.11753950
M3 - Article
C2 - 17853656
AN - SCOPUS:35448957243
SN - 1079-0268
VL - 30
SP - 346
EP - 354
JO - Journal of Spinal Cord Medicine
JF - Journal of Spinal Cord Medicine
IS - 4
ER -