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. 1996 Oct 1;16(19):6012-20.
doi: 10.1523/JNEUROSCI.16-19-06012.1996.

Activation of metabotropic glutamate receptor subtype mGluR1 contributes to post-traumatic neuronal injury

A Mukhin  1 , L Fan, A I Faden
Affiliations

Activation of metabotropic glutamate receptor subtype mGluR1 contributes to post-traumatic neuronal injury

A Mukhin et al. J Neurosci. .

Abstract

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.

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Figures

Fig. 1.
Fig. 1.
Trauma to mixed neuronal/glial cultures induced significant PI hydrolysis that was attenuated by treatment with an mGluR antagonist (500 μm MCPG added 30 min before injury). MCPG alone in control (uninjured) cultures had no significant effect on PI hydrolysis. PI hydrolysis was measured as accumulation of [3H]inositol phosphates from 5 min before and up to 30 min after injury. Data represent mean ± SEM;n = 16–22 cultures per condition. **p < 0.01 versus control (uninjured culture);†p < 0.05 versus injury (untreated injury), using the Student–Newman–Keuls test after ANOVA.
Fig. 2.
Fig. 2.
Both subtypes of PLC linked mGluR—mGluR1 (as mGluR1α splicing variant) and mGluR5—are found in neuronal/glial cultures used in these studies. Cell membranes (8 μg protein) were analyzed by SDS-PAGE and immunoblotting with mGluR1α- and mGluR5-specific antibodies, as described in Materials and Methods. When primary antibody was omitted from the incubation phase, the specific bands were not detected (data not shown). Data represent results of 18-DIV cell culture study; similar results were obtained in two additional experiments with 17- and 20-DIV cultures.
Fig. 3.
Fig. 3.
The agonist of group I mGluR DHPG in dose-dependent manner potentiates the injury-induced LDH release, which can be attenuated by the mGluR antagonist MCPG. Cultures were incubated in the presence of 2–32 μm DHPG (filled circles) or in the presence of 2–32 μm DHPG plus 1 mm MCPG (open circles) 30 min before and 30 min after injury. LDH levels were measured 16–18 hr after injury. Data represent mean ± SEM. DHPG alone: n = 19–20 cultures for each concentration; DHPG plus MCPG:n = 10 cultures for each concentration.
Fig. 4.
Fig. 4.
Treatment with MCPG attenuated neuronal injury after mechanical trauma to mixed neuronal/glial cultures, as reflected by changes in LDH release. Cultures were incubated in the absence or presence of 500 μm MCPG (A) or 12–1000 μm MCPG (B) 30 min before and 30 min after injury. LDH levels were measured 16–18 hr after injury. Data represent mean ± SEM. A, n = 25 cultures per condition; B, n = 18–20 cultures for each concentration; **p < 0.01 versus control (untreated injury) using Student’s ttest.
Fig. 5.
Fig. 5.
Treatment with 4CPG, a somewhat selective antagonist at group I mGluR at the concentration used (30 μm), also showed neuronal protection in vitro. Culture conditions, LDH measurements, and methods of drug administration were similar to those described in Figure 4. Data represent mean ± SEM; n = 46–50 cultures per condition. ***p < 0.001 versus control (untreated injury) using Student’s t test.
Fig. 6.
Fig. 6.
Intracerebroventricular administration ofR,S-MCPG (0.5 μmol/injection) at 15 min before and 1 hr after injury significantly improved neurological recovery after lateral fluid percussion-induced TBI in rats. Histograms represent median scores at different days post-trauma. Eachcircle represents individual animal cumulative neuroscore reflecting performance on a battery of motor tests.Filled circles, Untreated injury (vehicle),n = 12 animals; open circles, injury treated by R,S-MCPG,n = 9 animals. **p < 0.01 versus untreated injury (vehicle), using the Mann–WhitneyU test after Kruskal–Wallis nonparametric ANOVA.
Fig. 7.
Fig. 7.
Intracerebroventricular administration ofR,S-MCPG (0.5 μmol/injection) at 15 min before and 1 hr after injury attenuated post-traumatic cell loss in ipsilateral hippocampus measured 2 weeks after fluid percussion-induced TBI. Cells were counted after staining 8 μm coronal brain sections with cresyl violet. Data represent mean number of cells ± SEM per 0.25 × 0.25 mm field. Control group, n = 8 animals; R,S-MCPG-treated group,n = 5 animals. **p < 0.01 versus control (untreated injury, vehicle) using Student’st test.
Fig. 8.
Fig. 8.
Intravenous administration of 48 μmR,S-MCPG 15 min after injury significantly improved neurological recovery at 1 and 2 weeks after lateral fluid percussion-induced TBI in rats. Histograms represent median scores at different days post-trauma. Each circlerepresents individual animal cumulative neuroscore. Filled circles, Untreated injury (vehicle), n = 15 animals: open circles, injury treated byR,S-MCPG, n = 14 animals. **p < 0.01; ***p < 0.001 versus untreated injury (vehicle), using the Mann–WhitneyU test after Kruskal–Wallis nonparametric ANOVA.
Fig. 9.
Fig. 9.
Pretreatment with AS ODN directed to mGluR1, but not AS ODN directed to mGluR5, significantly reduced neuronal death after trauma in vitro. Treatment with mismatched (missense) MS ODN or with sense ODN (S ODN) had no significant effect on neuronal survival. Neuronal/glial cultures were treated with 2 μm appropriate ODN for 5 d. Neuronal death was evaluated as injury-induced LDH release 16–18 hr after injury. Data represent mean ± SEM; n = 30–40 cultures per condition. Multiple comparisons were performed using ANOVA and Student–Newman–Keuls test: **p < 0.01 versus control (untreated injury);††p < 0.01 versus MS ODN treatment;##p < 0.01 versus S ODN treatment.
Fig. 10.
Fig. 10.
Pretreatment with AS ODN directed to mGluR1 as well as pretreatment with AS ODN directed to mGluR5 significantly reduced 1S,3R-ACPD-induced PI hydrolysis. Treatment with mismatched (missense) ODN had no significant effect on 1S,3R-ACPD-induced PI hydrolysis. PI hydrolysis was measured as inositol phosphate (IP) accumulation within 30 min after addition of 500 μm1S,3R-ACPD. Data represent mean ± SEM; n = 30–40 cultures per condition. Multiple comparisons were performed using ANOVA and Student–Newman–Keuls test. **p < 0.01 versus control (untreated injury);††p < 0.01 versus MS ODN treatment.
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References

    1. Abe T, Sugihara H, Nawa H, Shigemoto R, Mizuno N, Nakanishi S. Molecular characterization of a novel metabotropic glutamate receptor mGluR5 coupled to inositol phosphate/Ca2+ signal transduction. J Biol Chem. 1992;267:13361–13368. - PubMed
    1. Amador E, Dorfman LE, Wacher WEC. Serum lactate dehydrogenase activity: an analytical assessment of current assays. Clin Chem. 1963;9:391–399. - PubMed
    1. Berridge MJ, Downes CP, Hanley MR. Lithium amplifies agonist-dependent phosphatidylinositol responses in brain and salivary glands. Biochem J. 1982;206:587–595. - PMC - PubMed
    1. Birrell GJ, Gordon MP, Marcoux FW. (1S ,3 R )-1-Aminocyclopentane-1,3-dicarboxylic acid attenuates N -methyl-d-aspartate-induced neuronal cell death in cortical cultures via a reduction in delayed Ca2+ accumulation. Neuropharmacology. 1993;32:1351–1358. - PubMed
    1. Brabet I, Mary S, Bockaert J, Pin J-P. Phenylglycine derivatives discriminate between mGluR1- and mGluR5-mediated responses. Neuropharmacology. 1995;34:895–903. - PubMed

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