Document Detail


Functional NMDA receptor subtype 2B is expressed in astrocytes after ischemia in vivo and anoxia in vitro.
MedLine Citation:
PMID:  12716944     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
NMDA-type glutamate receptors play a critical role in neuronal synaptogenesis, plasticity, and excitotoxic death. Recent studies indicate that functional NMDA receptors are also expressed in certain glial populations in the normal brain. Using immunohistochemical methods, we detected the presence of the NMDA receptor 2B (NR2B) subunit of the NMDA receptor in neurons but not astrocytes in the CA1 and subicular regions of the rat hippocampus. However, after ischemia-induced neuronal death in these regions, double immunohistochemical labeling revealed that NR2B subunits colocalized with the astrocyte marker glial fibrillary acid protein and with NR1 subunits that are required for functional NMDA receptors. NR2B expression was first observed 3 d after ischemia and reached a peak at 28 d. At 56 d, only a few NR2B-expressing astrocytes were still present. In vitro, when postnatal hippocampal cultures were subjected to 5 min of anoxia, it resulted in NR2B expression on astrocytes in the glial feed layer. Imaging of intracellular calcium with postanoxic cultures and astrocytes isolated acutely from the ischemic hippocampus revealed a rise in intracellular [Ca2+] after stimulation with the specific agonist NMDA. The response could be blocked reversibly with the competitive antagonist 2-amino-5-phosphonovalerate and attenuated by the NR2B-selective antagonist ifenprodil. Control astrocytes were not responsive to NMDA but responded to glutamate. An understanding of the role of astrocytes that express functional NMDA receptors in response to ischemia may guide development of novel stroke therapies.
Authors:
Claudia Krebs; Herman B Fernandes; Claire Sheldon; Lynn A Raymond; Kenneth G Baimbridge
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  23     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2003 Apr 
Date Detail:
Created Date:  2003-04-28     Completed Date:  2003-05-30     Revised Date:  2013-02-13    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3364-72     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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MeSH Terms
Descriptor/Qualifier:
2-Amino-5-phosphonovalerate / pharmacology
Animals
Astrocytes / cytology,  drug effects,  metabolism*
Axotomy
Brain Ischemia / metabolism*
Calcium / metabolism
Cell Hypoxia / physiology*
Cells, Cultured
Excitatory Amino Acid Agonists / pharmacology
Excitatory Amino Acid Antagonists / pharmacology
Glial Fibrillary Acidic Protein / biosynthesis
Hippocampus / cytology,  metabolism,  pathology
Immunohistochemistry
Male
N-Methylaspartate / pharmacology
Neurons / cytology,  drug effects,  metabolism
Piperidines / pharmacology
Rats
Rats, Wistar
Receptors, N-Methyl-D-Aspartate / agonists,  antagonists & inhibitors,  biosynthesis*
Chemical
Reg. No./Substance:
0/Excitatory Amino Acid Agonists; 0/Excitatory Amino Acid Antagonists; 0/Glial Fibrillary Acidic Protein; 0/NR1 NMDA receptor; 0/NR2B NMDA receptor; 0/Piperidines; 0/Receptors, N-Methyl-D-Aspartate; 6384-92-5/N-Methylaspartate; 7440-70-2/Calcium; 76726-92-6/2-Amino-5-phosphonovalerate; R8OE3P6O5S/ifenprodil

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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