Volume 16, Number 19,
Issue of October 1, 1996
pp. 6012-6020
Copyright ©1996 Society for Neuroscience
Activation of Metabotropic Glutamate Receptor Subtype mGluR1
Contributes to Post-Traumatic Neuronal Injury
Received April 2, 1996; revised June 28, 1996; accepted July 19, 1996.
Alexey Mukhin1,
Lei Fan1, and
Alan I. Faden2
1 Department of Neurology and the Institute for
Cognitive and Computational Sciences, and 2 Departments of
Neurology and Pharmacology and the Institute for Cognitive and
Computational Sciences, Georgetown University Medical Center,
Washington, DC 20007-2197
The role of phospholipase C-coupled (group I) metabotropic
glutamate receptors (mGluR1 and mGluR5) in post-traumatic neuronal
injury was examined using rat in vivo and in
vitro models. Traumatic injury to mixed neuronal/glial cultures
induced phosphoinositide hydrolysis and caused neuronal death.
Pharmacological blockade of group I receptors significantly reduced
these effects in vitro and decreased neurological
deficits as well as neuronal loss produced by traumatic brain injury
in vivo. In contrast, activation of group I receptors by
a specific agonist in vitro exacerbated post-traumatic
neuronal death in a dose-dependent manner. Antisense
oligodeoxynucleotide directed to mGluR1, but not to mGluR5, was
neuroprotective in vitro, although each
oligodeoxynucleotide reduced the respective receptor-stimulated
accumulation of inositol phosphates to a similar degree. Together,
these findings suggest that activation of mGluR1 contributes to
post-traumatic neuronal injury and that mGluR1 antagonists may have
therapeutic potential in brain injury.
Key words:
antisense oligodeoxynucleotides;
brain trauma;
metabotropic glutamate receptors;
neuronal injury;
neuroprotection;
phosphoinositide hydrolysis