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Balbi M, Bonanno G, Bonifacino T, Milanese M. The Physio-Pathological Role of Group I Metabotropic Glutamate Receptors Expressed by Microglia in Health and Disease with a Focus on Amyotrophic Lateral Sclerosis. Int J Mol Sci 2023; 24:5240. [PMID: 36982315 PMCID: PMC10048889 DOI: 10.3390/ijms24065240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/03/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
Microglia cells are the resident immune cells of the central nervous system. They act as the first-line immune guardians of nervous tissue and central drivers of neuroinflammation. Any homeostatic alteration that can compromise neuron and tissue integrity could activate microglia. Once activated, microglia exhibit highly diverse phenotypes and functions related to either beneficial or harmful consequences. Microglia activation is associated with the release of protective or deleterious cytokines, chemokines, and growth factors that can in turn determine defensive or pathological outcomes. This scenario is complicated by the pathology-related specific phenotypes that microglia can assume, thus leading to the so-called disease-associated microglia phenotypes. Microglia express several receptors that regulate the balance between pro- and anti-inflammatory features, sometimes exerting opposite actions on microglial functions according to specific conditions. In this context, group I metabotropic glutamate receptors (mGluRs) are molecular structures that may contribute to the modulation of the reactive phenotype of microglia cells, and this is worthy of exploration. Here, we summarize the role of group I mGluRs in shaping microglia cells' phenotype in specific physio-pathological conditions, including some neurodegenerative disorders. A significant section of the review is specifically focused on amyotrophic lateral sclerosis (ALS) since it represents an entirely unexplored topic of research in the field.
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Affiliation(s)
- Matilde Balbi
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy (M.M.)
| | - Giambattista Bonanno
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy (M.M.)
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Tiziana Bonifacino
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy (M.M.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
| | - Marco Milanese
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy (M.M.)
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
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Transcriptional regulation of NRF1 on metabotropic glutamate receptors in a neonatal hypoxic‑ischemic encephalopathy rat model. Pediatr Res 2022:10.1038/s41390-022-02353-9. [PMID: 36280709 DOI: 10.1038/s41390-022-02353-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Neonatal hypoxic-ischemic encephalopathy (HIE) is a kind of brain injury that causes severe neurological disorders in newborns. Metabotropic glutamate receptors (mGluRs) and ionotropic glutamate receptors (iGluRs) are significantly associated with HIE and are involved in ischemia-induced excitotoxicity. This study aimed to investigate the upstream mechanisms of mGluRs and the transcriptional regulation by nuclear respiratory factor 1 (NRF1). METHODS The rat model of neonatal HIE was created using unilateral carotid artery ligation and in vitro oxygen-glucose deprivation paradigm. We used western blot, immunofluorescence, Nissl staining, and Morris water maze to investigate the impact of NRF1 on brain damage and learning memory deficit by HIE. We performed ChIP and luciferase activities to identify the transcriptional regulation of NRF1 on mGluRs. RESULTS The neuronal NRF1 and some glutamatergic genes expression synchronously declined in infarcted tissues. The NRF1 overexpression effectively restored the expression of some glutamatergic genes and improved cognitive performance. NRF1 regulated some members of mGluRs and iGluRs in hypoxic-ischemic neurons. Finally, NRF1 is bound to the promoter regions of Grm1, Grm2, and Grm8 to activate their transcription. CONCLUSIONS NRF1 is involved in the pathology of the neonatal HIE rat model, suggesting a novel therapeutic approach to neonatal HIE. IMPACT NRF1 and some glutamatergic genes were synchronously downregulated in the infarcted brain of the neonatal HIE rat model. NRF1 overexpression could rescue cognitive impairment caused by the neonatal HIE rat model. NRF1 regulated the expressions of Grm1, Grm2, and Grm8, which activated their transcription by binding to the promoter regions.
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G-Protein-Coupled Receptors and Ischemic Stroke: a Focus on Molecular Function and Therapeutic Potential. Mol Neurobiol 2021; 58:4588-4614. [PMID: 34120294 DOI: 10.1007/s12035-021-02435-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/18/2021] [Indexed: 01/22/2023]
Abstract
In ischemic stroke, there is only one approved drug, tissue plasminogen activator, to be used in clinical conditions for thrombolysis. New neuroprotective therapies for ischemic stroke are desperately needed. Several targets and pathways have been shown to confer neuroprotective effects in ischemic stroke. G-protein-coupled receptors (GPCRs) are one of the most frequently targeted receptors for developing novel therapeutics for central nervous system disorders. GPCRs are a large family of cell surface receptors that response to a wide variety of extracellular stimuli. GPCRs are involved in a wide range of physiological and pathological processes. More than 90% of the identified non-sensory GPCRs are expressed in the brain, where they play important roles in regulating mood, pain, vision, immune responses, cognition, and synaptic transmission. There is also good evidence that GPCRs are implicated in the pathogenesis of stroke. This review narrates the pathophysiological role and possible targeted therapy of GPCRs in ischemic stroke.
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Bratek - Gerej E, Bronisz A, Ziembowicz A, Salinska E. Pretreatment with mGluR2 or mGluR3 Agonists Reduces Apoptosis Induced by Hypoxia-Ischemia in Neonatal Rat Brains. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8848015. [PMID: 33763176 PMCID: PMC7963909 DOI: 10.1155/2021/8848015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/04/2021] [Accepted: 02/23/2021] [Indexed: 11/17/2022]
Abstract
Hypoxia-ischemia (HI) in an immature brain results in energy depletion and excessive glutamate release resulting in excitotoxicity and oxidative stress. An increase in reactive oxygen species (ROS) production induces apoptotic processes resulting in neuronal death. Activation of group II mGluR was shown to prevent neuronal damage after HI. The application of agonists of mGluR3 (N-acetylaspartylglutamate; NAAG) or mGluR2 (LY379268) inhibits the release of glutamate and reduces neurodegeneration in a neonatal rat model of HI, although the exact mechanism is not fully recognized. In the present study, the effects of NAAG (5 mg/kg) and LY379268 (5 mg/kg) application (24 h or 1 h before experimental birth asphyxia) on apoptotic processes as the potential mechanism of neuroprotection in 7-day-old rats were investigated. Intraperitoneal application of NAAG or LY379268 at either time point before HI significantly reduced the number of TUNEL-positive cells in the CA1 region of the ischemic brain hemisphere. Both agonists reduced expression of the proapoptotic Bax protein and increased expression of Bcl-2. Decreases in HI-induced caspase-9 and caspase-3 activity were also observed. Application of NAAG or LY379268 24 h or 1 h before HI reduced HIF-1α formation likely by reducing ROS levels. It was shown that LY379268 concentration remains at a level that is required for activation of mGluR2 for up to 24 h; however, NAAG is quickly metabolized by glutamate carboxypeptidase II (GCPII) into glutamate and N-acetyl-aspartate. The observed effect of LY379268 application 24 h or 1 h before HI is connected with direct activation of mGluR2 and inhibition of glutamate release. Based on the data presented in this study and on our previous findings, we conclude that the neuroprotective effect of NAAG applied 1 h before HI is most likely the result of a combination of mGluR3 and NMDA receptor activation, whereas the beneficial effects of NAAG pretreatment 24 h before HI can be explained by the activation of NMDA receptors and induction of the antioxidative/antiapoptotic defense system triggered by mild excitotoxicity in neurons. This response to NAAG pretreatment is consistent with the commonly accepted mechanism of preconditioning.
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Affiliation(s)
- Ewelina Bratek - Gerej
- Department of Neurochemistry, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Bronisz
- Tumor Microenvironment Laboratory, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
| | - Apolonia Ziembowicz
- Department of Neurochemistry, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
| | - Elzbieta Salinska
- Department of Neurochemistry, Mossakowski Medical Research Institute Polish Academy of Sciences, Warsaw, Poland
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Rahman MS, Yang J, Luan Y, Qiu Z, Zhang J, Lu H, Chen X, Liu Y. Attenuation of Acute Intracerebral Hemorrhage-Induced Microglial Activation and Neuronal Death Mediated by the Blockade of Metabotropic Glutamate Receptor 5 In Vivo. Neurochem Res 2020; 45:1230-1243. [PMID: 32140955 DOI: 10.1007/s11064-020-03006-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/21/2020] [Accepted: 02/29/2020] [Indexed: 12/12/2022]
Abstract
The activation of microglia in response to intracerebral hemorrhagic stroke is one of the principal components of the progression of this disease. It results in the formation of pro-inflammatory cytokines that lead to neuronal death, a structural deterioration that, in turn interferes with functional recovery. Metabotropic glutamate receptor 5 (mGluR5) is highly expressed in reactive microglia and is involved in the pathological processes of brain disorders, but its role in intracerebral hemorrhage (ICH) remains unknown. We hypothesized that mGluR5 regulates microglial activation and ICH maintenance. In this study, collagenase-induced ICH mice received a single intraperitoneal injection of the mGluR5 antagonist-, MTEP, or vehicle 2 h after injury. We found that acute ICH upregulated mGluR5 and microglial activation. mGluR5 was highly localized in reactive microglia in the peri-hematomal cortex and striatum on days 3 and 7 post-ICH. The MTEP-mediated pharmacological inhibition of mGluR5 in vivo resulted in the substantial attenuation of acute microglial activation and IL-6, and TNF-α release. We also showed that the blockade of mGluR5 markedly reduced cell apoptosis, and neurodegeneration and markedly elevated neuroprotection. Furthermore, the MTEP-mediated inhibition of mGluR5 significantly reduced the lesion volume and improved functional recovery. Taken together, our results demonstrate that ICH injury enhances mGluR5 expression in the acute and subacute stages and that mGluR5 is highly localized in reactive microglia. The blockade of mGluR5 reduces ICH-induced acute microglial activation, provides neuroprotection and promotes neurofunctional recovery after ICH. The inhibition of mGluR5 may be a relevant therapeutic target for intracerebral hemorrhagic stroke.
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Affiliation(s)
- Md Saidur Rahman
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China.,Department of Anatomy and Histology, Patuakhali Science and Technology University, Dhaka, Bangladesh
| | - Jianbo Yang
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yan Luan
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Zhengguo Qiu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, 710038, Shaanxi, People's Republic of China
| | - Jianshui Zhang
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Haixia Lu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Xinlin Chen
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China.
| | - Yong Liu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China.
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Yamasaki T, Fujinaga M, Yui J, Wakizaka H, Ohya T, Nengaki N, Ogawa M, Ikoma Y, Hatori A, Xie L, Kawamura K, Zhang MR. Improved Visualization and Specific Binding for Metabotropic Glutamate Receptor Subtype 1 (mGluR1) Using [11C]ITMM with Ultra-High Specific Activity in Small-Animal PET. PLoS One 2015; 10:e0130006. [PMID: 26076143 PMCID: PMC4468202 DOI: 10.1371/journal.pone.0130006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 04/29/2015] [Indexed: 12/15/2022] Open
Abstract
Metabotropic glutamate receptor subtype 1 (mGluR1) is a crucial target in the development of new medications to treat central nervous system (CNS) disorders. Recently, we developed N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-4-[11C]methoxy-N-methyl-benzamide ([11C]ITMM) as a useful positron emission tomography (PET) probe for mGluR1 in clinical studies. Here, we aimed to improve visualization and threshold of specific binding for mGluR1 using [11C]ITMM with ultra-high specific activity (SA) of > 3,500 GBq/μmol in rat brains. A two-tissue compartment model indicated large differences between the two SAs in the constants k3 and k4, representing binding ability for mGluR1, while constants K1 and k2 showed no differences. The total distribution volume (VT) values of conventional and ultra-high SA were 9.1 and 11.2 in the thalamus, 7.7 and 9.7 in the striatum, and 6.4 and 8.5 mL/cm3 in the substantia nigra, respectively. The specific binding of [11C]ITMM with ultra-high SA was significantly higher than the conventional SA, especially in the basal ganglia. Parametric PET images scaled with VT of the ultra-high SA clearly identified regional differences in the rat brain. In conclusion, PET studies using [11C]ITMM with ultra-high SA could sufficiently improve visualization and specific binding for mGluR1, which could help further understanding for mGluR1 functions in CNS disorders.
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Affiliation(s)
- Tomoteru Yamasaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
- * E-mail:
| | - Masayuki Fujinaga
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Joji Yui
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Hidekatsu Wakizaka
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Tomoyuki Ohya
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Nobuki Nengaki
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Masanao Ogawa
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Yoko Ikoma
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Akiko Hatori
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Lin Xie
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazunori Kawamura
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Ming-Rong Zhang
- Molucular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
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Souza LC, Wilhelm EA, Bortolatto CF, Nogueira CW, Boeira SP, Jesse CR. Involvement of mGlu5 receptor in 3-nitropropionic acid-induced oxidative stress in rat striatum. Neurol Res 2014; 36:833-40. [PMID: 24588139 DOI: 10.1179/1743132814y.0000000334] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES The excitotoxin 3-nitropropionic acid (3-NP) induces a suitable experimental model of Huntington's disease (HD). This compound induces neurodegeneration via glutamatergic activation and oxidative stress, suggesting that the metabotropic glutamate receptor blockage and free radical scavenging are potential therapeutic targets in HD. In this study, we evaluated the role of 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl]-pyridine (MTEP), a selective mGlu5 receptor antagonist, in a 3-NP model of HD. METHODS We administered 3-NP (20 mg/kg, intraperitoneal) to rats for 4 days. MTEP at doses of 2·5 and 5 mg/kg was administered 30 min before 3-NP. Behavioral tests and biochemical experiments were performed to assess the effects of 3-NP and the ability of MTEP to ameliorate these changes. RESULTS 3-NP administration induced body weight loss, decreased locomotor activity, and inhibition of succinate dehydrogenase and Na(+)-K(+) adenosine triphosphate (ATP)ase activities in rat striatum. We also observed increases in reactive species (RS) levels and glutathione reductase activity, decreased non-protein thiol levels, and an inhibition of glutathione peroxidase activity in the striatum of rats treated with 3-NP. Notably, all of these effects were attenuated by MTEP treatment. DISCUSSION Our results demonstrate the neuroprotective effect of MTEP and reinforce the involvement of mGluR5 in 3-NP-induced oxidative stress in rat striatum.
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Hypobaric Hypoxia Postconditioning Reduces Brain Damage and Improves Antioxidative Defense in the Model of Birth Asphyxia in 7-Day-Old Rats. Neurochem Res 2013; 39:68-75. [DOI: 10.1007/s11064-013-1191-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/23/2013] [Accepted: 10/26/2013] [Indexed: 12/13/2022]
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Inhibition of the group I mGluRs reduces acute brain damage and improves long-term histological outcomes after photothrombosis-induced ischaemia. ASN Neuro 2013; 5:195-207. [PMID: 23772679 PMCID: PMC3786425 DOI: 10.1042/an20130002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Group I mGluRs (metabotropic glutamate receptors), including mGluR1 and mGluR5, are GPCRs (G-protein coupled receptors) and play important roles in physiology and pathology. Studies on their role in cerebral ischaemia have provided controversial results. In this study, we used a PT (photothrombosis)-induced ischaemia model to investigate whether antagonists to the group I mGluRs may offer acute and long-term protective effects in adult mice. Our results demonstrated that administration with mGluR5 antagonist MPEP [2-methyl-6-(phenylethynyl)-pyridine] or mGluR1 antagonist LY367385 by intraperitoneal injection at 3 h after PT decreased brain infarct volume evaluated one day after ischaemia. Additive effects on infarct volume were observed upon co-injection with MPEP and LY367385. These antagonists also significantly alleviated neurodegeneration and apoptosis in the penumbra. In addition, when evaluated 2 weeks after PT, they reduced infarct volume and tissue loss, attenuated glial scar formation, and inhibited cell proliferation in the penumbra. Importantly, co-injection with MPEP and LY367385 reduced the expression levels of calpain, a Ca2+-activated protease known to mediate ischaemia-induced neuronal death. Injection of calpeptin, a calpain inhibitor, could inhibit neuronal death and brain damage after PT but injection of calpeptin together with MPEP and LY367385 did not further improve the protective effects mediated by MPEP and LY367385. These results suggest that inhibition of group I mGluRs is sufficient to protect ischaemic damage through the calpain pathway. Taken together, our results demonstrate that inhibition of group I mGluRs can mitigate PT-induced brain damage through attenuating the effects of calpain, and improve long-term histological outcomes.
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Modulation of neurological deficits and expression of glutamate receptors during experimental autoimmune encephalomyelitis after treatment with selected antagonists of glutamate receptors. BIOMED RESEARCH INTERNATIONAL 2013; 2013:186068. [PMID: 23936777 PMCID: PMC3722774 DOI: 10.1155/2013/186068] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/02/2013] [Indexed: 12/02/2022]
Abstract
The aim of our investigation was to characterize the role of group I mGluRs and NMDA receptors in pathomechanisms of experimental autoimmune encephalomyelitis (EAE), the rodent model of MS. We tested the effects of LY 367385 (S-2-methyl-4-carboxyphenylglycine, a competitive antagonist of mGluR1), MPEP (2-methyl-6-(phenylethynyl)-pyridine, an antagonist of mGluR5), and the uncompetitive NMDA receptor antagonists amantadine and memantine on modulation of neurological deficits observed in rats with EAE. The neurological symptoms of EAE started at 10-11 days post-injection (d.p.i.) and peaked after 12-13 d.p.i. The protein levels of mGluRs and NMDA did not increase in early phases of EAE (4 d.p.i.), but starting from 8 d.p.i. to 25 d.p.i., we observed a significant elevation of mGluR1 and mGluR5 protein expression by about 20% and NMDA protein expression by about 10% over the control at 25 d.p.i. The changes in protein levels were accompanied by changes in mRNA expression of group I mGluRs and NMDARs. During the late disease phase (20–25 d.p.i.), the mRNA expression levels reached 300% of control values. In contrast, treatment with individual receptor antagonists resulted in a reduction of mRNA levels relative to untreated animals.
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Perinatal hypoxic-ischemic brain injury affects the glutamatergic signal transduction coupled with neuronal ADP-ribosyl cyclase activity. Bull Exp Biol Med 2012; 150:583-6. [PMID: 22235390 DOI: 10.1007/s10517-011-1196-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Agonists of glutamate ionotropic (NMDA) and metabotropic receptors (mGluRI and mGluRIII) had the regulatory effect on ADP-ribosyl cyclase/CD38 activity in cerebellar granular cells of newborn rats. Perinatal hypoxic-ischemic brain injury was followed by dysregulation of this mechanism.
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Śmiałowska M, Gołembiowska K, Kajta M, Zięba B, Dziubina A, Domin H. Selective mGluR1 antagonist EMQMCM inhibits the kainate-induced excitotoxicity in primary neuronal cultures and in the rat hippocampus. Neurotox Res 2012; 21:379-92. [PMID: 22144346 PMCID: PMC3296950 DOI: 10.1007/s12640-011-9293-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 11/07/2011] [Accepted: 11/23/2011] [Indexed: 10/25/2022]
Abstract
Abundant evidence suggests that indirect inhibitory modulation of glutamatergic transmission, via metabotropic glutamatergic receptors (mGluR), may induce neuroprotection. The present study was designed to determine whether the selective antagonist of mGluR1 (3-ethyl-2-methyl-quinolin-6-yl)-(4-methoxy-cyclohexyl)-methanone methanesulfonate (EMQMCM), showed neuroprotection against the kainate (KA)-induced excitotoxicity in vitro and in vivo. In in vitro studies on mouse primary cortical and hippocampal neuronal cultures, incubation with KA (150 μM) induced strong degeneration [measured as lactate dehydrogenase (LDH) efflux] and apoptosis (measured as caspase-3 activity). EMQMCM (0.1-100 μM) added 30 min to 6 h after KA, significantly attenuated the KA-induced LDH release and prevented the increase in caspase-3 activity in the cultures. Those effects were dose- and time-dependent. In in vivo studies KA (2.5 nmol/1 μl) was unilaterally injected into the rat dorsal CA1 hippocampal region. Degeneration was calculated by counting surviving neurons in the CA pyramidal layer using stereological methods. It was found that EMQMCM (5-10 nmol/1 μl) injected into the dorsal hippocampus 30 min, 1 h, or 3 h (the higher dose only) after KA significantly prevented the KA-induced neuronal degeneration. In vivo microdialysis studies in rat hippocampus showed that EMQMCM (100 μM) significantly increased γ-aminobutyric acid (GABA) and decreased glutamate release. When perfused simultaneously with KA, EMQMCM substantially increased GABA release and prevented the KA-induced glutamate release. The obtained results indicate that the mGluR1 antagonist, EMQMCM, may exert neuroprotection against excitotoxicity after delayed treatment (30 min to 6 h). The role of enhanced GABAergic transmission in the neuroprotection is postulated.
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Affiliation(s)
- Maria Śmiałowska
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland.
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Zhao YD, Cheng SY, Ou S, Chen PH, Ruan HZ. Functional response of hippocampal CA1 pyramidal cells to neonatal hypoxic-ischemic brain damage. Neurosci Lett 2012; 516:5-8. [PMID: 22402191 DOI: 10.1016/j.neulet.2012.02.067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/11/2012] [Accepted: 02/21/2012] [Indexed: 11/24/2022]
Abstract
Perinatal hypoxic-ischemic (H-I) is a major cause of brain injury in the newborn. The hippocampus is more sensitive to H-I injury than the other brain regions. It is believed that H-I brain damage causes a loss of neurons in the central nervous system. The patterns of neuronal death include apoptosis and necrosis. With regard to the responses of neurons, the neural functional changes should be earlier than the morphologic changes. The aim of the present study is to evaluate the electrophysiological characteristics and the synaptic transmission functions. Seven-day-old Sprague-Dawley rat pups were randomly divided into sham operation and H-I groups. The patch clamp, immunohistochemistry and Western blotting techniques were used to achieve this objective. The results of the study showed a decrease in neuronal excitability and a significant increase in the frequency of spontaneous excitatory postsynaptic currents and the duration of EPSCs in the CA1 pyramidal cells of H-I brain damage rats. The glutamate transporter subtype 1 (GLT-1) expression level of the hippocampal CA1 area in the H-I group was decreased compared with the control. There was no difference in the amplitude of excitatory postsynaptic currents and should be no difference in the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR), N-methyl-D-aspartate receptor (NMDAR) and synaptophysin between the control and H-I brain injury group. These results revealed that changes of electrophysiological characteristics and synaptic functions occur instantly after H-I brain damage in the hippocampal pyramidal cells of neonatal rats. The failure to eliminate glutamate should be one of the important factors of excitotoxicity injury on hippocampal CA1 pyramidal cells, while neuronal excitation was not increased in the H-I brain injury model.
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Affiliation(s)
- Yan-Dong Zhao
- Department of Neurobiology, College of Basic Medical Sciences, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
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Metabotropic glutamate receptors in neurodegeneration/neuroprotection: still a hot topic? Neurochem Int 2012; 61:559-65. [PMID: 22306345 DOI: 10.1016/j.neuint.2012.01.017] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 01/14/2012] [Accepted: 01/14/2012] [Indexed: 01/17/2023]
Abstract
Moving from early studies, we here review the most recent evidence linking metabotropic glutamate (mGlu) receptors to processes of neurodegeneration/neuroprotection. The use of knockout mice and subtype-selective drugs has increased our knowledge of the precise role played by individual mGlu receptor subtypes in these processes. Activation of mGlu1 and mGlu5 receptors may either amplify or reduce neuronal damage depending on the context and the nature of the toxic insults. In contrast, mGlu1 and mGlu5 receptors antagonists are consistently protective in in vitro and in vivo models of neuronal death. A series of studies suggest that mGlu1 receptor antagonists or negative allosteric modulators (NAMs) are promising candidates for the treatment of ischemic brain damage, whereas mGlu5 receptor NAMs, which have been clinically developed for the treatment of Parkinson's disease (PD) and l-DOPA-induced dyskinesias, protect nigro-striatal dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity in mice and monkeys. Activation of glial mGlu3 receptors promotes the formation of various neurotrophic factors, such as transforming growth factor-β (TGF-β), glial-derived neurotrophic factor (GDNF), nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF). Hence, selective mGlu3 receptor agonists or positive allosteric modulators (PAMs) (not yet available) are potentially helpful in the treatment of chronic neurodegenerative disorders such as PD, Alzheimer's disease (AD), and amyotrophic lateral sclerosis. Selective mGlu2 receptor PAMs should be used with caution in AD patients because these drugs are shown to amplify β-amyloid neurotoxicity. Finally, mGlu4 receptor agonists/PAMs share with mGlu5 receptor NAMs the ability to improve motor symptoms associated with PD and attenuate nigro-striatal degeneration at the same time. No data are yet available on the role of mGlu7 and mGlu8 receptors in neurodegeneration/neuroprotection.
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Activation of NOX2 by the Stimulation of Ionotropic and Metabotropic Glutamate Receptors Contributes to Glutamate Neurotoxicity In Vivo Through the Production of Reactive Oxygen Species and Calpain Activation. J Neuropathol Exp Neurol 2011; 70:1020-35. [DOI: 10.1097/nen.0b013e3182358e4e] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Domin H, Zięba B, Gołembiowska K, Kowalska M, Dziubina A, Śmiałowska M. Neuroprotective potential of mGluR5 antagonist MTEP: effects on kainate-induced excitotoxicity in the rat hippocampus. Pharmacol Rep 2010; 62:1051-61. [DOI: 10.1016/s1734-1140(10)70367-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 11/19/2010] [Indexed: 11/16/2022]
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McIldowie MJ, Gandy MN, Skelton BW, Brotchie JM, Koutsantonis GA, Spackman MA, Piggott MJ. Physical and crystallographic characterisation of the mGlu5 antagonist MTEP and its monohydrochloride. J Pharm Sci 2010; 99:234-45. [DOI: 10.1002/jps.21823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Effect of MPEP on rat's behavioral activity in experimental episodes of hypoxia. Adv Med Sci 2009; 54:277-82. [PMID: 20022861 DOI: 10.2478/v10039-009-0041-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The influence of the selective antagonism of metabotropic glutamate receptor subtype 5 (mGluR5) by MPEP (2-methyl-6-(phenylethynyl)-pyridine) on some behaviors was tested in control groups of rats and in rats exposed to short-term hypoxia once or to repeated episodes of hypoxia. MATERIAL AND METHODS We used the following methods: the open field test, the passive avoidance test and the object recognition test. Experimental hypoxia was produced by placing rats in a glass chamber flushed with a mixture of 2% O2 in N2. RESULTS MPEP applied intravenously (IV) at the dose of 1 mg kg-1 significantly enhanced locomotor and exploratory activity, impaired acquisition, but improved consolidation and retrieval in the passive avoidance situation and did not alter rats' activity in the object recognition test. The single short-term hypoxia significantly inhibited motility of rats and profoundly impaired acquisition, consolidation and retrieval processes, but the positive effect of MPEP on retrieval was preserved. Hypoxia also did not influence the activity of rats in the object recognition object. The repeated episodes of short-term hypoxia were induced for five consecutive days and it also inhibited motility of rats, but did not change consolidation and retrieval processes. The episodes of hypoxia significantly diminished the beneficial effect of MPEP on consolidation and retrieval, and also the enhancement of locomotor and exploratory activity. MPEP, used in rats subjected to the single or the repeated episodes of short-term hypoxia, did not change recognition memory. CONCLUSION MPEP used before the single episode of hypoxia only, had beneficial effect on retrieval.
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Zhou M, Xu W, Liao G, Bi X, Baudry M. Neuroprotection against neonatal hypoxia/ischemia-induced cerebral cell death by prevention of calpain-mediated mGluR1alpha truncation. Exp Neurol 2009; 218:75-82. [PMID: 19374898 PMCID: PMC2696556 DOI: 10.1016/j.expneurol.2009.04.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 03/27/2009] [Accepted: 04/07/2009] [Indexed: 11/28/2022]
Abstract
Many cellular events are involved in ischemic neuronal death, and it has been difficult to identify those that play a critical role in the cascade triggered by lack of oxygen and glucose, although it has been widely recognized that overactivation of glutamate receptors represents one of the initiating factors. Different glutamate receptor antagonists, especially those for N-methyl-D-aspartate (NMDA) receptors, have achieved significant success in animal models of hypoxia/ischemia; however, these antagonists have failed in clinical trials. We previously reported that calpain-mediated truncation of metabotropic glutamate receptor 1alpha (mGluR1alpha) played a critical role in excitotoxicity, and that a TAT-mGluR1 peptide consisting of a peptide surrounding the calpain cleavage site of mGluR1alpha and the peptide transduction domain of the transactivating regulatory protein (TAT) of HIV was neuroprotective against excitotoxicity. In the present study we tested the effect of this peptide in in vitro and in vivo models of neonatal hypoxia/ischemia. TAT-mGluR1 peptide prevented oxygen/glucose deprivation- (OGD) and hypoxia/ischemia- (H/I) induced neuronal death in cultured hippocampal slices and neonatal rats, respectively. TAT-mGluR1 blocked H/I-induced mGluR1alpha degradation but had no effect on H/I-induced spectrin degradation, suggesting that neuroprotection was due to prevention of calpain-mediated mGluR1alpha truncation and not to calpain inhibition. Our results therefore suggest that mGluR1alpha truncation plays a critical role in neonatal hypoxia/ischemia and that blockade of this event may prevent the activation of many downstream cytotoxic cascades. Compared to glutamate receptor antagonists and general calpain inhibitors, TAT-mGluR1 may have limited side effects.
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Affiliation(s)
- Miou Zhou
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089
| | - Wei Xu
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089
| | - Guanghong Liao
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766
| | - Xiaoning Bi
- Department of Basic Medical Sciences, Western University of Health Sciences, Pomona, CA 91766
| | - Michel Baudry
- Neuroscience Program, University of Southern California, Los Angeles, CA 90089
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Besheer J, Faccidomo S, Grondin JJM, Hodge CW. Effects of mGlu1-receptor blockade on ethanol self-administration in inbred alcohol-preferring rats. Alcohol 2008; 42:13-20. [PMID: 18164577 PMCID: PMC2350187 DOI: 10.1016/j.alcohol.2007.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 11/01/2007] [Accepted: 11/03/2007] [Indexed: 11/30/2022]
Abstract
The Group I family of metabotropic glutamate receptors includes subtype 1 (mGlu1) and subtype 5 (mGlu5) receptors. This family of receptors has generated interest as potential targets for different areas of therapeutic development, including intervention for alcohol and drug abuse. Most of this interest is driven by findings showing involvement of mGlu5 receptors in the regulation of drug self-administration; however, studies examining the role of mGlu1 receptors in drug self-administration are limited. The purpose of this work was to examine the role of mGlu1-receptor antagonism in the maintenance of ethanol self-administration and the self-administration of an alternate nondrug reward, sucrose. Male alcohol-preferring inbred rats were trained to self-administer ethanol (15% vol/vol) versus water on a concurrent schedule of reinforcement, and the effect of the mGlu1-receptor antagonist JNJ16259685 (0.1-1.0mg/kg intraperitoneal [IP]) was evaluated on self-administration. The rats were then trained to self-administer sucrose (0.4% wt/vol) versus water, and the same dose range of JNJ16259685 was tested. Locomotor activity was tested in a separate assessment to evaluate potential nonspecific motor effects of the antagonist. Ethanol self-administration was dose dependently reduced by JNJ16259685. This reduction was likely due to a motor impairment as the lowest effective dose (0.1mg/kg) significantly reduced locomotor behavior. Sucrose self-administration was reduced by the highest JNJ16259685 dose (1.0mg/kg), and this reduction was also likely due to a motor impairment. Interestingly, ethanol self-administration was more sensitive to mGlu1-receptor antagonism than sucrose self-administration as lower JNJ16259685 doses reduced ethanol-reinforced responding and motor behavior. Together, these results suggest that mGlu1 receptors do not play a specific role in modulating ethanol self-administration or the self-administration of an alternate nondrug reward (i.e., sucrose).
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Affiliation(s)
- J Besheer
- Bowles Center for Alcohol Studies, Department of Psychiatry, Thurston-Bowles Building, CB#7178, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA.
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Besheer J, Faccidomo S, Grondin JJM, Hodge CW. Regulation of motivation to self-administer ethanol by mGluR5 in alcohol-preferring (P) rats. Alcohol Clin Exp Res 2008; 32:209-21. [PMID: 18162077 PMCID: PMC2532085 DOI: 10.1111/j.1530-0277.2007.00570.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Emerging evidence indicates that Group I metabotropic glutamate receptors (mGluR1 and mGluR5) differentially regulates ethanol self-administration in several rodent behavioral models. The purpose of this work was to further characterize involvement of Group I mGluRs in the reinforcing effects of ethanol using a progressive ratio schedule of reinforcement. METHODS Alcohol-preferring (P) rats were trained to self-administer ethanol (15% v/v) versus water on a concurrent schedule of reinforcement, and the effects of the Group I mGluR antagonists were evaluated on progressive ratio performance. The rats were then trained to self-administer sucrose (0.4% w/v) versus water, and the effects of the antagonists were tested on progressive ratio performance. RESULTS The mGluR1 antagonist, 3,4-dihydro-2H-pyrano[2,3]b quinolin-7-yl (cis-4-methoxycyclohexyl) methanone (JNJ 16259685; 0 to 1 mg/kg) and the mGluR5 antagonist, 6-methyl-2-(phenylethynyl) pyridine (MPEP; 0 to 10 mg/kg) dose-dependently reduced ethanol break point. In separate locomotor activity assessments, the lowest effective dose of JNJ 16259685 (0.3 mg/kg) produced a motor impairment, whereas the lowest effective dose of MPEP (3 mg/kg) did not. Thus, the reduction in ethanol break point by mGluR1 antagonism was probably a result of a motor impairment. JNJ 16259685 (0.3 mg/kg) and MPEP (10 mg/kg) reduced sucrose break point and produced motor impairments. Thus, the reductions in sucrose break point produced by both Group I antagonists were probably because of nonspecific effects on motor activity. CONCLUSIONS Together, these results suggest that glutamate activity at mGluR5 regulates motivation to self-administer ethanol.
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Affiliation(s)
- Joyce Besheer
- Bowles Center for Alcohol Studies, Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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Baudry M. New neuroprotective approaches for stroke: use of decoy peptides targeting specific molecular events. FUTURE NEUROLOGY 2007. [DOI: 10.2217/14796708.2.4.343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Michel Baudry
- University of Southern California, Neuroscience Program, Los Angeles, CA 90089-2520, USA
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Szydlowska K, Kaminska B, Baude A, Parsons CG, Danysz W. Neuroprotective activity of selective mGlu1 and mGlu5 antagonists in vitro and in vivo. Eur J Pharmacol 2006; 554:18-29. [PMID: 17109843 DOI: 10.1016/j.ejphar.2006.09.061] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2006] [Revised: 09/21/2006] [Accepted: 09/26/2006] [Indexed: 11/27/2022]
Abstract
The neuroprotective potential of allosteric mGlu5 and mGlu1 antagonists such as 6-methyl-2-(phenylethynyl)-pyridin (MPEP)/[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) and (3-ethyl-2-methyl-quinolin-6-yl)-(4-methoxy-cyclohexyl)-methanone methanesulfonate (EMQMCM), was tested in vitro in organotypic hippocampal cultures and in the middle cerebral artery occlusion model of stroke in vivo. Both classes of agent have high selectivity toward mGlu sub-types and are active in animal models of various diseases indicating satisfactory CNS penetration. In organotypic hippocampal cultures MPEP showed high neuroprotective potency against sub-chronic (12 days) insult produced by 3-NP with an IC50 of c.a. 70 nM. In contrast, although the mGlu1 antagonist EMQMCM was also protective, it seems to be weaker yielding an IC50 of c.a. 1 microM. Similarly, in the transient (90 min) middle cerebral artery occlusion model of ischaemia in rats, MTEP seems to be more effective than EMQMCM. MTEP, at 2.5 mg/kg and at 5 mg/kg provided 50 and 70% neuroprotection if injected 2 h after the onset of ischaemia. At a dose of 5 mg/kg, significant (50%) neuroprotection was also seen if the treatment was delayed by 4 h. EMQMCM was not protective at 5 mg/kg (given 2 h after occlusion) but at 10 mg/kg 50% of neuroprotection was observed. The present data support stronger neuroprotective potential of mGlu5 than mGlu1 antagonists.
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Affiliation(s)
- Kinga Szydlowska
- Laboratory of Transcription Regulation, The Nencki Institute of Experimental Biology, Pasteur 3 Street, 02-093 Warsaw, Poland
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Duszczyk M, Gadamski R, Ziembowicz A, Lazarewicz JW. Antagonists of group I metabotropic glutamate receptors do not inhibit induction of ischemic tolerance in gerbil hippocampus. Neurochem Int 2006; 48:478-84. [PMID: 16524644 DOI: 10.1016/j.neuint.2005.12.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 12/19/2005] [Accepted: 12/22/2005] [Indexed: 10/24/2022]
Abstract
In this study we tested the effect of antagonists of two subtypes of the group I metabotropic glutamate receptors (mGluRs GI) on the induction of ischemic tolerance in relation to brain temperature. These experiments were prompted by indications that glutamate receptors may participate in the mechanisms of ischemic preconditioning. The role of NMDA receptors in the induction of ischemic tolerance has been debated while there is lack of information concerning the involvement of mGluRs GI in this phenomenon. The tolerance to injurious 3 min forebrain ischemia in Mongolian gerbils was induced 48 h earlier by 2 min preconditioning ischemia. Brain temperature was measured using telemetry equipment. EMQMCM and MTEP, antagonists of mGluR1 and mGluR5, respectively, were injected i.p. at a dose of 5 mg/kg. They were administered either before preconditioning ischemia in a single dose or after 2 min ischemia three times every 2 h. Both antagonists did not inhibit the induction of ischemic tolerance. Thus, our data indicate that group I metabotropic glutamate receptors do not play an essential role in the induction of ischemic tolerance.
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Affiliation(s)
- Malgorzata Duszczyk
- Department of Neurochemistry, Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warsaw, Poland
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