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Abstract
The cerebral microcirculation undergoes dynamic changes in parallel with the development of neurons, glia, and their energy metabolism throughout gestation and postnatally. Cerebral blood flow (CBF), oxygen consumption, and glucose consumption are as low as 20% of adult levels in humans born prematurely but eventually exceed adult levels at ages 3 to 11 years, which coincide with the period of continued brain growth, synapse formation, synapse pruning, and myelination. Neurovascular coupling to sensory activation is present but attenuated at birth. By 2 postnatal months, the increase in CBF often is disproportionately smaller than the increase in oxygen consumption, in contrast to the relative hyperemia seen in adults. Vascular smooth muscle myogenic tone increases in parallel with developmental increases in arterial pressure. CBF autoregulatory response to increased arterial pressure is intact at birth but has a more limited range with arterial hypotension. Hypoxia-induced vasodilation in preterm fetal sheep with low oxygen consumption does not sustain cerebral oxygen transport, but the response becomes better developed for sustaining oxygen transport by term. Nitric oxide tonically inhibits vasomotor tone, and glutamate receptor activation can evoke its release in lambs and piglets. In piglets, astrocyte-derived carbon monoxide plays a central role in vasodilation evoked by glutamate, ADP, and seizures, and prostanoids play a large role in endothelial-dependent and hypercapnic vasodilation. Overall, homeostatic mechanisms of CBF regulation in response to arterial pressure, neuronal activity, carbon dioxide, and oxygenation are present at birth but continue to develop postnatally as neurovascular signaling pathways are dynamically altered and integrated. © 2021 American Physiological Society. Compr Physiol 11:1-62, 2021.
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Lee JK, Liu D, Jiang D, Kulikowicz E, Tekes A, Liu P, Qin Q, Koehler RC, Aggarwal M, Zhang J, Martin LJ. Fractional anisotropy from diffusion tensor imaging correlates with acute astrocyte and myelin swelling in neonatal swine models of excitotoxic and hypoxic-ischemic brain injury. J Comp Neurol 2021; 529:2750-2770. [PMID: 33543493 DOI: 10.1002/cne.25121] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 02/07/2023]
Abstract
The specific cytopathology that causes abnormal fractional anisotropy (FA) and mean diffusivity (MD) from diffusion tensor imaging (DTI) after neonatal hypoxia-ischemia (HI) is not completely understood. The panoply of cell types in the brain might contribute differentially to changes in DTI metrics. Because glia are the predominant cell type in brain, we hypothesized that changes in FA and MD would signify perturbations in glial microstructure. Using a 3-Tesla clinical scanner, we conducted in vivo DTI MRI in nine neonatal piglets at 20-96 h after excitotoxic brain injury from striatal quinolinic acid injection or global HI. FA and MD from putamen, caudate, and internal capsule in toto were correlated with astrocyte swelling, neuronal excitotoxicity, and white matter injury. Low FA correlated with more swollen astrocytes immunophenotyped by aquaporin-4 (AQP4), glial fibrillary acidic protein (GFAP), and glutamate transporter-1 (GLT-1). Low FA was also related to the loss of neurons with perineuronal GLT-1+ astrocyte decorations, large myelin swellings, lower myelin density, and oligodendrocyte cell death identified by 2',3'-cyclic nucleotide 3'-phosphodiesterase, bridging integrator-1, and nuclear morphology. MD correlated with degenerating oligodendrocytes and depletion of normal GFAP+ astrocytes but not with astrocyte or myelin swelling. We conclude that FA is associated with cytotoxic edema in astrocytes and oligodendrocyte processes as well as myelin injury at the cellular level. MD can detect glial cell death and loss, but it may not discern subtle pathology in swollen astrocytes, oligodendrocytes, or myelin. This study provides a cytopathologic basis for interpreting DTI in the neonatal brain after HI.
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Affiliation(s)
- Jennifer K Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Dapeng Liu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Dengrong Jiang
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ewa Kulikowicz
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Aylin Tekes
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Peiying Liu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Qin Qin
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Raymond C Koehler
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Manisha Aggarwal
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jiangyang Zhang
- Department of Radiology, New York University, New York, New York, USA
| | - Lee J Martin
- Department of Pathology, Johns Hopkins University, Baltimore, Maryland, USA
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Koehler RC, Yang ZJ, Lee JK, Martin LJ. Perinatal hypoxic-ischemic brain injury in large animal models: Relevance to human neonatal encephalopathy. J Cereb Blood Flow Metab 2018; 38:2092-2111. [PMID: 30149778 PMCID: PMC6282216 DOI: 10.1177/0271678x18797328] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Perinatal hypoxia-ischemia resulting in death or lifelong disabilities remains a major clinical disorder. Neonatal models of hypoxia-ischemia in rodents have enhanced our understanding of cellular mechanisms of neural injury in developing brain, but have limitations in simulating the range, accuracy, and physiology of clinical hypoxia-ischemia and the relevant systems neuropathology that contribute to the human brain injury pattern. Large animal models of perinatal hypoxia-ischemia, such as partial or complete asphyxia at the time of delivery of fetal monkeys, umbilical cord occlusion and cerebral hypoperfusion at different stages of gestation in fetal sheep, and severe hypoxia and hypoperfusion in newborn piglets, have largely overcome these limitations. In monkey, complete asphyxia produces preferential injury to cerebellum and primary sensory nuclei in brainstem and thalamus, whereas partial asphyxia produces preferential injury to somatosensory and motor cortex, basal ganglia, and thalamus. Mid-gestational fetal sheep provide a valuable model for studying vulnerability of progenitor oligodendrocytes. Hypoxia followed by asphyxia in newborn piglets replicates the systems injury seen in term newborns. Efficacy of post-insult hypothermia in animal models led to the success of clinical trials in term human neonates. Large animal models are now being used to explore adjunct therapy to augment hypothermic neuroprotection.
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Affiliation(s)
- Raymond C Koehler
- 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Zeng-Jin Yang
- 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer K Lee
- 1 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA.,2 The Pathobiology Graduate Training Program, Johns Hopkins University, Baltimore, MD, USA
| | - Lee J Martin
- 2 The Pathobiology Graduate Training Program, Johns Hopkins University, Baltimore, MD, USA.,3 Department of Pathology, Division of Neuropathology, Johns Hopkins University, Baltimore, MD, USA
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Dupuis N, Enderlin J, Thomas J, Desnous B, Dournaud P, Allorge D, Auvin S. Anti-ictogenic and antiepileptogenic properties of perampanel in mature and immature rats. Epilepsia 2017; 58:1985-1992. [DOI: 10.1111/epi.13894] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Nina Dupuis
- National Institute of Health and Medical Research, U1141; Paris France
- Sorbonne Paris Cité; Paris Diderot University; National Institute of Health and Medical Research UMR1141; Paris France
| | - Julie Enderlin
- National Institute of Health and Medical Research, U1141; Paris France
- Sorbonne Paris Cité; Paris Diderot University; National Institute of Health and Medical Research UMR1141; Paris France
| | - Jeremy Thomas
- Functional Toxicology Unit, Lille University Hospital Center; Lille France
| | - Béatrice Desnous
- National Institute of Health and Medical Research, U1141; Paris France
- Sorbonne Paris Cité; Paris Diderot University; National Institute of Health and Medical Research UMR1141; Paris France
- Pediatric Neurology Department; Robert Debré Hospital; Public Hospital Network of Paris; Paris France
| | - Pascal Dournaud
- National Institute of Health and Medical Research, U1141; Paris France
- Sorbonne Paris Cité; Paris Diderot University; National Institute of Health and Medical Research UMR1141; Paris France
| | - Delphine Allorge
- Functional Toxicology Unit, Lille University Hospital Center; Lille France
| | - Stéphane Auvin
- National Institute of Health and Medical Research, U1141; Paris France
- Sorbonne Paris Cité; Paris Diderot University; National Institute of Health and Medical Research UMR1141; Paris France
- Pediatric Neurology Department; Robert Debré Hospital; Public Hospital Network of Paris; Paris France
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Hadzic M, Jack A, Wahle P. Ionotropic glutamate receptors: Which ones, when, and where in the mammalian neocortex. J Comp Neurol 2016; 525:976-1033. [PMID: 27560295 DOI: 10.1002/cne.24103] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/09/2016] [Accepted: 08/15/2016] [Indexed: 12/14/2022]
Abstract
A multitude of 18 iGluR receptor subunits, many of which are diversified by splicing and RNA editing, localize to >20 excitatory and inhibitory neocortical neuron types defined by physiology, morphology, and transcriptome in addition to various types of glial, endothelial, and blood cells. Here we have compiled the published expression of iGluR subunits in the areas and cell types of developing and adult cortex of rat, mouse, carnivore, bovine, monkey, and human as determined with antibody- and mRNA-based techniques. iGluRs are differentially expressed in the cortical areas and in the species, and all have a unique developmental pattern. Differences are quantitative rather than a mere absence/presence of expression. iGluR are too ubiquitously expressed and of limited use as markers for areas or layers. A focus has been the iGluR profile of cortical interneuron types. For instance, GluK1 and GluN3A are enriched in, but not specific for, interneurons; moreover, the interneurons expressing these subunits belong to different types. Adressing the types is still a major hurdle because type-specific markers are lacking, and the frequently used neuropeptide/CaBP signatures are subject to regulation by age and activity and vary as well between species and areas. RNA-seq reveals almost all subunits in the two morphofunctionally characterized interneuron types of adult cortical layer I, suggesting a fairly broad expression at the RNA level. It remains to be determined whether all proteins are synthesized, to which pre- or postsynaptic subdomains in a given neuron type they localize, and whether all are involved in synaptic transmission. J. Comp. Neurol. 525:976-1033, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Minela Hadzic
- Developmental Neurobiology, Faculty for Biology and Biotechnology ND 6/72, Ruhr University Bochum, 44801, Bochum, Germany
| | - Alexander Jack
- Developmental Neurobiology, Faculty for Biology and Biotechnology ND 6/72, Ruhr University Bochum, 44801, Bochum, Germany
| | - Petra Wahle
- Developmental Neurobiology, Faculty for Biology and Biotechnology ND 6/72, Ruhr University Bochum, 44801, Bochum, Germany
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Bhattacharyya S. Inside story of Group I Metabotropic Glutamate Receptors (mGluRs). Int J Biochem Cell Biol 2016; 77:205-12. [PMID: 26987586 DOI: 10.1016/j.biocel.2016.03.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/31/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are G-protein coupled receptors (GPCRs) that are activated by the neurotransmitter glutamate in the central nervous system. Among the eight subtypes, mGluR1 and mGluR5 belong to the group I family. These receptors play important roles in the brain and are believed to be involved in multiple forms of experience dependent synaptic plasticity including learning and memory. In addition, group I mGluRs also have been implicated in various neuropsychiatric disorders like Fragile X syndrome, autism etc. The normal signaling depends on the precise location of these receptors in specific region of the neuron and the process of receptor trafficking plays a crucial role in controlling this localization. Intracellular trafficking could also regulate the desensitization, resensitization, down-regulation and intracellular signaling of these receptors. In this review I focus on the current understanding of group I mGluR regulation in the central nervous system and also their role in neuropsychiatric disorders.
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Affiliation(s)
- Samarjit Bhattacharyya
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Knowledge city, Sector-81, SAS Nagar, PO: 140306, Punjab, India.
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Wang B, Armstrong JS, Reyes M, Kulikowicz E, Lee JH, Spicer D, Bhalala U, Yang ZJ, Koehler RC, Martin LJ, Lee JK. White matter apoptosis is increased by delayed hypothermia and rewarming in a neonatal piglet model of hypoxic ischemic encephalopathy. Neuroscience 2015; 316:296-310. [PMID: 26739327 DOI: 10.1016/j.neuroscience.2015.12.046] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/12/2015] [Accepted: 12/24/2015] [Indexed: 11/29/2022]
Abstract
Therapeutic hypothermia is widely used to treat neonatal hypoxic ischemic (HI) brain injuries. However, potentially deleterious effects of delaying the induction of hypothermia and of rewarming on white matter injury remain unclear. We used a piglet model of HI to assess the effects of delayed hypothermia and rewarming on white matter apoptosis. Piglets underwent HI injury or sham surgery followed by normothermic or hypothermic recovery at 2h. Hypothermic groups were divided into those with no rewarming, slow rewarming at 0.5°C/h, or rapid rewarming at 4°C/h. Apoptotic cells in the subcortical white matter of the motor gyrus, corpus callosum, lateral olfactory tract, and internal capsule at 29h were identified morphologically and counted by hematoxylin & eosin staining. Cell death was verified by terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling (TUNEL) assay. White matter neurons were also counted, and apoptotic cells were immunophenotyped with the oligodendrocyte marker 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase). Hypothermia, slow rewarming, and rapid rewarming increased apoptosis in the subcortical white matter relative to normothermia (p<0.05). The number of white matter neurons was not lower in groups with more apoptosis after hypothermia or rapid rewarming, indicating that the apoptosis occurred among glial cells. Hypothermic piglets had more apoptosis in the lateral olfactory tract than those that were rewarmed (p<0.05). The promotion of apoptosis by hypothermia and rewarming in these regions was independent of HI. In the corpus callosum, HI piglets had more apoptosis than shams after normothermia, slow rewarming, and rapid rewarming (p<0.05). Many apoptotic cells were myelinating oligodendrocytes identified by CNPase positivity. Our results indicate that delaying the induction of hypothermia and rewarming are associated with white matter apoptosis in a piglet model of HI; in some regions these temperature effects are independent of HI. Vulnerable cells include myelinating oligodendrocytes. This study identifies a deleterious effect of therapeutic hypothermia in the developing brain.
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Affiliation(s)
- B Wang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - J S Armstrong
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - M Reyes
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - E Kulikowicz
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - J-H Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - D Spicer
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - U Bhalala
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - Z-J Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - R C Koehler
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States
| | - L J Martin
- Department of Pathology, Division of Neuropathology, JHU, United States
| | - J K Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD (JHU), United States.
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Grados M, Prazak M, Saif A, Halls A. A review of animal models of obsessive-compulsive disorder: a focus on developmental, immune, endocrine and behavioral models. Expert Opin Drug Discov 2015; 11:27-43. [PMID: 26558411 DOI: 10.1517/17460441.2016.1103225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by intrusive thoughts (obsessions) and/or repetitive behaviors (compulsions). Several models of OCD exist, many which employ behaviors such as over-grooming or hoarding as correlates for compulsive behaviors - often using a response to serotonergic agents as evidence for their validity. Recent discoveries in the genetics of OCD and the identification of aberrancies of glutamatergic, hormonal, and immune pathways in the OCD phenotype highlight a need to review existing of animal models of OCD. The focus of attention to these pathways may lead to possible new targets for drug discovery. AREAS COVERED In this review, the authors describe frameworks for animal models in OCD conceptualized as either biological (e.g., developmental, genetic, and endocrine pathways), or behavioral (e.g., repetitive grooming, and stereotypies). In addition, the authors give special attention to the emerging role of glutamate in OCD. EXPERT OPINION While many animal models for OCD demonstrate pathologic repetitive behavior phenotypes, which are relieved by serotoninergic agents, animal models based on reversal learning, perseverative responding, and neurodevelopmental mechanisms represent robust new paradigms. Glutamatergic influences in these new animal models suggest that drug discovery using neuroprotective approaches may represent a new stage for pharmacologic developments in OCD.
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Affiliation(s)
- Marco Grados
- a Department of Psychiatry , Johns Hopkins University , 1800 Orleans St. - 12th floor, Baltimore , MD 21287 , USA
| | - Michael Prazak
- b Department of Medicine , Dow University of Health Sciences , Karachi , Pakistan
| | - Aneeqa Saif
- c Department of Psychology Grand Forks , University of North Dakota , ND , USA
| | - Andrew Halls
- a Department of Psychiatry , Johns Hopkins University , 1800 Orleans St. - 12th floor, Baltimore , MD 21287 , USA
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Titomanlio L, Fernández-López D, Manganozzi L, Moretti R, Vexler ZS, Gressens P. Pathophysiology and neuroprotection of global and focal perinatal brain injury: lessons from animal models. Pediatr Neurol 2015; 52:566-584. [PMID: 26002050 PMCID: PMC4720385 DOI: 10.1016/j.pediatrneurol.2015.01.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 01/16/2015] [Accepted: 01/24/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND Arterial ischemic stroke occurs more frequently in term newborns than in the elderly, and brain immaturity affects mechanisms of ischemic injury and recovery. The susceptibility to injury of the brain was assumed to be lower in the perinatal period as compared with childhood. This concept was recently challenged by clinical studies showing marked motor disabilities after stroke in neonates, with the severity of motor and cortical sensory deficits similar in both perinatal and childhood ischemic stroke. Our understanding of the triggers and the pathophysiological mechanisms of perinatal stroke has greatly improved in recent years, but many factors remain incompletely understood. METHODS In this review, we focus on the pathophysiology of perinatal stroke and on therapeutic strategies that can protect the immature brain from the consequences of stroke by targeting inflammation and brain microenvironment. RESULTS Studies in neonatal rodent models of cerebral ischemia have suggested a potential role for soluble inflammatory molecules as important modulators of injury and recovery. A great effort is underway to investigate neuroprotective molecules based on our increasing understanding of the pathophysiology. CONCLUSION In this review, we provide a comprehensive summary of new insights concerning pathophysiology of focal and global perinatal brain injury and their implications for new therapeutic approaches.
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Affiliation(s)
- Luigi Titomanlio
- Pediatric Emergency Department, APHP, Robert Debré Hospital, Paris, France
- Inserm, U1141, F-75019 Paris, France
| | - David Fernández-López
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94158-0663, USA
| | - Lucilla Manganozzi
- Pediatric Emergency Department, APHP, Robert Debré Hospital, Paris, France
- Inserm, U1141, F-75019 Paris, France
| | | | - Zinaida S. Vexler
- Department of Neurology, University of California San Francisco, San Francisco, CA, 94158-0663, USA
| | - Pierre Gressens
- Inserm, U1141, F-75019 Paris, France
- Univ Paris Diderot, Sorbonne Paris Cité, UMRS 676, F-75019 Paris, France
- PremUP, Paris, France
- Centre for the Developing Brain, King’s College, St Thomas’ Campus, London SE1 7EH, UK
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Abstract
The developing mammalian cerebral cortex contains a distinct class of cells, subplate neurons (SPns), that play an important role during early development. SPns are the first neurons to be generated in the cerebral cortex, they reside in the cortical white matter, and they are the first to mature physiologically. SPns receive thalamic and neuromodulatory inputs and project into the developing cortical plate, mostly to layer 4. Thus SPns form one of the first functional cortical circuits and are required to relay early oscillatory activity into the developing cortical plate. Pathophysiological impairment or removal of SPns profoundly affects functional cortical development. SPn removal in visual cortex prevents the maturation of thalamocortical synapses, the maturation of inhibition in layer 4, the development of orientation selective responses and the formation of ocular dominance columns. SPn removal also alters ocular dominance plasticity during the critical period. Therefore, SPns are a key regulator of cortical development and plasticity. SPns are vulnerable to injury during prenatal stages and might provide a crucial link between brain injury in development and later cognitive malfunction.
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Affiliation(s)
- Patrick O Kanold
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA.
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Catania MV, D'Antoni S, Bonaccorso CM, Aronica E, Bear MF, Nicoletti F. Group I metabotropic glutamate receptors: a role in neurodevelopmental disorders? Mol Neurobiol 2008; 35:298-307. [PMID: 17917118 DOI: 10.1007/s12035-007-0022-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 11/30/1999] [Accepted: 04/09/2007] [Indexed: 11/26/2022]
Abstract
Group I metabotropic glutamate receptors (mGlu1 and mGlu5) are coupled to polyphosphoinositide hydrolysis and are involved in activity-dependent forms of synaptic plasticity, both during development and in the adult life. Group I mGlu receptors can also regulate proliferation, differentiation, and survival of neural stem/progenitor cells, which further support their role in brain development. An exaggerated response to activation of mGlu5 receptors may underlie synaptic dysfunction in Fragile X syndrome, the most common inherited form of mental retardation. In addition, group I mGlu receptors are overexpressed in dysplastic neurons of focal cortical dysplasia and hemimegaloencephaly, which are disorders of cortical development associated with chronic epilepsy. Drugs that block the activity of group I mGlu receptors (in particular, mGlu5 receptors) are potentially helpful for the treatment of Fragile X syndrome and perhaps other neurodevelopmental disorders.
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Affiliation(s)
- Maria Vincenza Catania
- Institute of Neurological Sciences, National Research Council (CNR), vl. Regina Margherita 6, Catania, 95123, Italy.
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Adult Olfactory Bulb Neural Precursor Cell Grafts Provide Temporary Protection From Motor Neuron Degeneration, Improve Motor Function, and Extend Survival in Amyotrophic Lateral Sclerosis Mice. J Neuropathol Exp Neurol 2007; 66:1002-18. [DOI: 10.1097/nen.0b013e318158822b] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Harris AP, Ohata H, Koehler RC. Role of nitric oxide in cerebrovascular reactivity to NMDA and hypercapnia during prenatal development in sheep. Int J Dev Neurosci 2007; 26:47-55. [PMID: 17935926 DOI: 10.1016/j.ijdevneu.2007.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 08/13/2007] [Accepted: 08/29/2007] [Indexed: 11/30/2022] Open
Abstract
Cerebral vasodilatory responses evoked by activation of NMDA receptors and by hypercapnia are important factors in the integrated vascular response to perinatal cerebral ischemia. Cerebral vasodilation to NMDA is mediated by nitric oxide in adult and newborn animals, whereas vasodilation to hypercapnia is thought to become modulated by nitric oxide, at least in swine, after the newborn period. The developmental role of nitric oxide in the cerebral blood flow response to NMDA and hypercapnia was investigated at mid- and late gestation in fetal sheep. Superfusion of 300microM NMDA over the cerebral cortex through a closed cranial window on the exteriorized head of an anesthetized fetus increased laser-Doppler flow by 41+/-7% (+/-S.E.) at 0.65 gestation. The increase was reduced by superfusion of a nitric oxide synthase inhibitor (18+/-8%). At 0.9 gestation, the response to NMDA was augmented (85+/-24%) compared to that at 0.65 gestation and was reduced by a nitric oxide synthase inhibitor (32+/-6%). In unanesthetized fetal sheep, hypercapnic reactivity of microsphere-determined cerebral blood flow was not significantly attenuated by nitric oxide synthase inhibition at 0.65 gestation (4.6+/-0.7 to 3.7+/-1.0% change/mmHg pCO2) or at 0.9 gestation (4.0+/-0.7 to 3.5+/-0.9% change/mmHg pCO2). Therefore, nitric oxide-dependent cerebrovascular dilation to NMDA-receptor activation is present as early as 0.65 gestation in fetal sheep and increases further during the last trimester, whereas vasodilation to hypercapnia remains unchanged and independent of nitric oxide during the last trimester. Hence, cerebrovascular reactivities to different stimuli do not mature concurrently.
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Affiliation(s)
- Andrew P Harris
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
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Talos DM, Follett PL, Folkerth RD, Fishman RE, Trachtenberg FL, Volpe JJ, Jensen FE. Developmental regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor subunit expression in forebrain and relationship to regional susceptibility to hypoxic/ischemic injury. II. Human cerebral white matter and cortex. J Comp Neurol 2006; 497:61-77. [PMID: 16680761 PMCID: PMC2987718 DOI: 10.1002/cne.20978] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This report is the second of a two-part evaluation of developmental differences in alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subunit expression in cell populations within white matter and cortex. In part I, we reported that, in rat, developmental expression of Ca2+-permeable (GluR2-lacking) AMPARs correlated at the regional and cellular level with increased susceptibility to hypoxia/ischemia (H/I), suggesting an age-specific role of these receptors in the pathogenesis of brain injury. Part II examines the regional and cellular progression of AMPAR subunits in human white matter and cortex from midgestation through early childhood. Similarly to the case in the rodent, there is a direct correlation between selective vulnerability to H/I and expression of GluR2-lacking AMPARs in human brain. For midgestational cases aged 20-24 postconceptional weeks (PCW) and for premature infants (25-37 PCW), we found that radial glia, premyelinating oligodendrocytes, and subplate neurons transiently expressed GluR2-lacking AMPARs. Notably, prematurity represents a developmental window of selective vulnerability for white matter injury, such as periventricular leukomalacia (PVL). During term (38-42 PCW) and postterm neonatal (43-46 PCW) periods, age windows characterized by increased susceptibility to cortical injury and seizures, GluR2 expression was low in the neocortex, specifically on cortical pyramidal and nonpyramidal neurons. This study indicates that Ca2+-permeable AMPAR blockade may represent an age-specific therapeutic strategy for potential use in humans. Furthermore, these data help to validate specific rodent maturational stages as appropriate models for evaluation of H/I pathophysiology.
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Affiliation(s)
- Delia M. Talos
- Department of Neurology Children's Hospital Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02115
| | - Pamela L. Follett
- Department of Neurology Children's Hospital Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02115
| | - Rebecca D. Folkerth
- Department of Pathology (Neuropathology), Children's Hospital Boston, Massachusetts 02115
- Department of Pathology, Brigham and Women's Hospital Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02115
| | - Rachel E. Fishman
- Department of Neurology Children's Hospital Boston, Massachusetts 02115
| | | | - Joseph J. Volpe
- Department of Neurology Children's Hospital Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02115
| | - Frances E. Jensen
- Department of Neurology Children's Hospital Boston, Massachusetts 02115
- Program in Neuroscience Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02115
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15
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Ferraguti F, Shigemoto R. Metabotropic glutamate receptors. Cell Tissue Res 2006; 326:483-504. [PMID: 16847639 DOI: 10.1007/s00441-006-0266-5] [Citation(s) in RCA: 388] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Accepted: 05/31/2006] [Indexed: 12/22/2022]
Abstract
Metabotropic glutamate receptors (mGlus) are a family of G-protein-coupled receptors activated by the neurotransmitter glutamate. Molecular cloning has revealed eight different subtypes (mGlu1-8) with distinct molecular and pharmacological properties. Multiplicity in this receptor family is further generated through alternative splicing. mGlus activate a multitude of signalling pathways important for modulating neuronal excitability, synaptic plasticity and feedback regulation of neurotransmitter release. In this review, we summarize anatomical findings (from our work and that of other laboratories) describing their distribution in the central nervous system. Recent evidence regarding the localization of these receptors in peripheral tissues will also be examined. The distinct regional, cellular and subcellular distribution of mGlus in the brain will be discussed in view of their relationship to neurotransmitter release sites and of possible functional implications.
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Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Innsbruck Medical University, Peter Mayr Strasse 1a, A-6020, Innsbruck, Austria
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16
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Balland B, Lachamp P, Strube C, Kessler JP, Tell F. Glutamatergic synapses in the rat nucleus tractus solitarii develop by direct insertion of calcium-impermeable AMPA receptors and without activation of NMDA receptors. J Physiol 2006; 574:245-61. [PMID: 16690712 PMCID: PMC1817785 DOI: 10.1113/jphysiol.2006.108738] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Calcium influxes through ionotropic glutamate receptors (AMPA and NMDA receptors, AMPARs and NMDARs) are considered to be critical for the shaping and refinement of neural circuits during synaptogenesis. Using a combined morphological and electrophysiological approach, we evaluated this hypothesis at the level of the nucleus tractus solitarii (NTS), a brainstem structure that is a gateway for many visceral sensory afferent fibres. We confirmed that in the NTS, the first excitatory synapses appeared at embryonic day 18. We next characterized the biophysical properties of NTS AMPARs. Throughout perinatal development, both evoked and miniature EPSCs recorded in the presence of an NMDAR blocker were insensitive to polyamines and had linear current-voltage relationships. This demonstrated that AMPARs at NTS excitatory synapses were calcium-impermeable receptors composed of a majority of GluR2 subunits. We then investigated the influence of calcium influxes through NMDARs on the development of NTS synaptic transmission. We found that NMDAR expression at synaptic sites did not precede AMPAR expression. Moreover, NMDAR blockade in utero did not prevent the development of AMPAR synaptic currents and the synaptic clustering of GluR2 subunits. Thus, our data support an alternative model of synaptogenesis that does not depend on calcium influxes through either AMPARs or NMDARs. This model may be particularly relevant to the formation of neural networks devoted to basic behaviours required at birth for survival.
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Affiliation(s)
- Bénédicte Balland
- Laboratoire de Neurophysiologie Cellulaire, CNRS UMR 6150, IFR Jean-Roche, Faculté de Médecine, Bd Pierre Dramard, 13916 Marseille cedex 20, France
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17
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Dean JM, Fraser M, Shelling AN, Bennet L, George S, Shaikh S, Scheepens A, Gunn AJ. Ontogeny of AMPA and NMDA receptor gene expression in the developing sheep white matter and cerebral cortex. ACTA ACUST UNITED AC 2006; 139:242-50. [PMID: 15963598 DOI: 10.1016/j.molbrainres.2005.05.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 05/07/2005] [Accepted: 05/15/2005] [Indexed: 11/22/2022]
Abstract
This study examined the hypothesis that the high prevalence of white matter injury in premature infants is associated with increased expression of calcium-permeable forms of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype of glutamate receptors in pre-myelinating white matter. We characterized expression of subunits of the AMPA, and for reference, the N-methyl-d-aspartate (NMDA), glutamate receptors at 0.5, 0.65, 0.85, and term gestation in the ovine fetal white matter and cerebral cortex. There was a low expression of the critical calcium-impermeable AMPA receptor GluR2 subunit in subcortical white matter both absolutely and relative to other AMPA subunits throughout gestation. In contrast, GluR2 subunit mRNA expression fell in the cerebral cortex with increasing gestation whereas protein expression increased. These findings suggest a vulnerability of subcortical white matter to AMPA receptor-mediated calcium toxicity throughout the second half of gestation. Thus, the hypothesis that AMPA receptor-mediated glutamate toxicity contributes to brain damage in premature infants needs to be revised.
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MESH Headings
- Age Factors
- Analysis of Variance
- Animals
- Blotting, Western/methods
- Cerebral Cortex/anatomy & histology
- Cerebral Cortex/embryology
- Cerebral Cortex/metabolism
- Embryo, Mammalian
- Female
- Gene Expression/physiology
- Gene Expression Regulation, Developmental/physiology
- Male
- Pregnancy
- RNA, Messenger/metabolism
- Rats
- Receptors, AMPA/classification
- Receptors, AMPA/genetics
- Receptors, AMPA/metabolism
- Receptors, N-Methyl-D-Aspartate/classification
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Sheep
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Affiliation(s)
- Justin M Dean
- Department of Physiology, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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18
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McQuillen PS, Ferriero DM. Perinatal subplate neuron injury: implications for cortical development and plasticity. Brain Pathol 2005; 15:250-60. [PMID: 16196392 PMCID: PMC8096042 DOI: 10.1111/j.1750-3639.2005.tb00528.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Perinatal brain injury may result in widespread deficits in visual, motor and cognitive systems suggesting disrupted brain development. Neurosensory and cognitive impairment are observed at increasing frequency with decreasing gestational ages, suggesting a unique vulnerability of the developing brain. The peak of human subplate neuron development coincides with the gestational ages of highest vulnerability to perinatal brain injury in the premature infant. At the same time, human thalamocortical connections are forming and being refined by activity-dependent mechanisms during critical periods. Subplate neurons are the first cortical neurons to mature and are selectively vulnerable to early hypoxic-ischemic brain injury in animal models. Timing of subplate neuron death determines the resulting defect in thalamocortical development: very early excitotoxic subplate neuron death results in failure of thalamocortical innervation, while later subplate neuron death interferes with the refinement of thalamocortical connections into mature circuits. We suggest that subplate neuron injury may be a central component of perinatal brain injury resulting in specific neurodevelopmental consequences.
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Affiliation(s)
- P S McQuillen
- Department of Pediatrics, Box 0106, University of California San Francisco Medical Center, San Francisco, CA 94143-0106, USA.
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19
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Sfaello I, Baud O, Arzimanoglou A, Gressens P. Topiramate prevents excitotoxic damage in the newborn rodent brain. Neurobiol Dis 2005; 20:837-48. [PMID: 16009561 DOI: 10.1016/j.nbd.2005.05.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 05/11/2005] [Accepted: 05/17/2005] [Indexed: 10/25/2022] Open
Abstract
Brain lesions induced in newborn mice by the glutamatergic agonists ibotenate (acting on NMDA and metabotropic receptors) and S-bromowillardiine (acting on AMPA-kainate receptors) mimic some aspects of white matter cysts and transcortical necrosis observed in human perinatal brain damage. Topiramate (TPM), already used in children to manage newly diagnosed and refractory epilepsy, has potential neuroprotective effects that may be useful in human perinatal brain lesions. In the excitotoxic newborn mouse model, TPM provided dose-dependent and long-lasting protection of developing white matter and cortical plate against S-bromowillardiine. TPM had no significant effect on ibotenate-induced brain lesions. TPM-induced neuroprotection potentially involved increased survival of pre-oligodendrocytes, decreased neuronal apoptosis, inhibition of microglial activation and astrogliosis, and decreased seizure activity. Diazepam, phenytoin, and carbamazepine had no neuroprotective effect in this model. The present study provides experimental support for the consideration of TPM as a candidate therapy for excitotoxic perinatal brain lesions.
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MESH Headings
- Alanine/analogs & derivatives
- Alanine/antagonists & inhibitors
- Alanine/toxicity
- Animals
- Animals, Newborn
- Brain/drug effects
- Brain/growth & development
- Brain/physiopathology
- Cerebral Palsy/drug therapy
- Cerebral Palsy/physiopathology
- Cerebral Palsy/prevention & control
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Excitatory Amino Acid Agonists/metabolism
- Excitatory Amino Acid Agonists/toxicity
- Excitatory Amino Acid Antagonists/pharmacology
- Excitatory Amino Acid Antagonists/therapeutic use
- Female
- Fructose/analogs & derivatives
- Fructose/pharmacology
- Fructose/therapeutic use
- Glutamic Acid/metabolism
- Humans
- Hypoxia, Brain/drug therapy
- Hypoxia, Brain/physiopathology
- Hypoxia, Brain/prevention & control
- Ibotenic Acid/antagonists & inhibitors
- Ibotenic Acid/toxicity
- Infant, Newborn
- Leukomalacia, Periventricular/drug therapy
- Leukomalacia, Periventricular/physiopathology
- Leukomalacia, Periventricular/prevention & control
- Male
- Mice
- Neuroprotective Agents/pharmacology
- Neuroprotective Agents/therapeutic use
- Neurotoxins/antagonists & inhibitors
- Neurotoxins/toxicity
- Rats
- Rats, Sprague-Dawley
- Topiramate
- Treatment Outcome
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Affiliation(s)
- Ignacio Sfaello
- INSERM U 676, Hôpital Robert Debré, 48 Boulevard Sérurier, F-75019 Paris, France
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20
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Furuta A, Takashima S, Yokoo H, Rothstein JD, Wada K, Iwaki T. Expression of glutamate transporter subtypes during normal human corticogenesis and type II lissencephaly. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 155:155-64. [PMID: 15804404 DOI: 10.1016/j.devbrainres.2005.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 01/24/2005] [Accepted: 01/26/2005] [Indexed: 10/25/2022]
Abstract
Glutamate transporters are thought to have an important role in central nervous system (CNS) development. We investigated the expression of the sodium-dependent high-affinity glutamate transporters EAAT1, EAAT2, and EAAT3 in 11 human autopsied cases without neurological disorders and in four cases with type II lissencephaly including Walker Warburg's syndrome (WWS) and Fukuyama-type congenital muscular dystrophy (FCMD), both of which are classified as migration disorders of the human brain. Expression of glutamate transporter subtypes was differentially regulated during normal human corticogenesis. Although EAAT1 and EAAT2 were mainly localized to the cortical astrocytes in the postnatal brain, EAAT1 was enriched in the proliferative zones and radial glia from 13 gestational weeks (GW) to 20 GW. EAAT2 was abundant in the intermediate zone until 23 GW, and transiently expressed in the radial fibers of the transitional form of radial glia into mature astrocytes as well as partly in the corticofugal axonal bundles. EAAT3 immunoreactivity was robust in the apical dendrites of the pyramidal neurons in the marginal zone and cortical plate during corticogenesis, and decreased postnatally. In the individuals with type II lissencephaly, glutamate transporters were expressed in the extrusion of neuroglial tissue. Bundles of EAAT2-immunoreactive radial fibers were prominent in the specimens at 20 GW. Thus, glutamate transporters are differentially regulated during normal and impaired corticogenesis. Altered glutamate transporter expression in type II lissencephaly suggests that glutamate metabolism is involved in the formation of the normal cortex and contributes to the disorganized cortex seen in migration disorders.
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Affiliation(s)
- Akiko Furuta
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo 187-8502, Japan.
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21
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Mueller D, Shamblott MJ, Fox HE, Gearhart JD, Martin LJ. Transplanted human embryonic germ cell-derived neural stem cells replace neurons and oligodendrocytes in the forebrain of neonatal mice with excitotoxic brain damage. J Neurosci Res 2005; 82:592-608. [PMID: 16247803 DOI: 10.1002/jnr.20673] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Stem cell therapy is a hope for the treatment of some childhood neurological disorders. We examined whether human neural stem cells (hNSCs) replace lost cells in a newborn mouse model of brain damage. Excitotoxic lesions were made in neonatal mouse forebrain with the N-methyl-D-aspartate (NMDA) receptor agonist quinolinic acid (QA). QA induced apoptosis in neocortex, hippocampus, striatum, white matter, and subventricular zone. This degeneration was associated with production of cleaved caspase-3. Cells immunopositive for inducible nitric oxide synthase were present in damaged white matter and subventricular zone. Three days after injury, mice received brain parenchymal or intraventricular injections of hNSCs derived from embryonic germ (EG) cells. Human cells were prelabeled in vitro with DiD for in vivo tracking. The locations of hNSCs within the mouse brain were determined through DiD fluorescence and immunodetection of human-specific nestin and nuclear antigen 7 days after transplantation. hNSCs survived transplantation into the lesioned mouse brain, as evidenced by human cell markers and DiD fluorescence. The cells migrated away from the injection site and were found at sites of injury within the striatum, hippocampus, thalamus, and white matter tracts and at remote locations in the brain. Subsets of grafted cells expressed neuronal and glial cell markers. hNSCs restored partially the complement of striatal neurons in brain-damaged mice. We conclude that human EG cell-derived NSCs can engraft successfully into injured newborn brain, where they can survive and disseminate into the lesioned areas, differentiate into neuronal and glial cells, and replace lost neurons. (c) 2005 Wiley-Liss, Inc.
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Affiliation(s)
- Dawn Mueller
- Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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22
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Luján R, Shigemoto R, López-Bendito G. Glutamate and GABA receptor signalling in the developing brain. Neuroscience 2005; 130:567-80. [PMID: 15590141 DOI: 10.1016/j.neuroscience.2004.09.042] [Citation(s) in RCA: 284] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2004] [Indexed: 10/26/2022]
Abstract
Our understanding of the role played by neurotransmitter receptors in the developing brain has advanced in recent years. The major excitatory and inhibitory neurotransmitters in the brain, glutamate and GABA, activate both ionotropic (ligand-gated ion channels) and metabotropic (G protein-coupled) receptors, and are generally associated with neuronal communication in the mature brain. However, before the emergence of their role in neurotransmission in adulthood, they also act to influence earlier developmental events, some of which occur prior to synapse formation: such as proliferation, migration, differentiation or survival processes during neural development. To fulfill these actions in the constructing of the nervous system, different types of glutamate and GABA receptors need to be expressed both at the right time and at the right place. The identification by molecular cloning of 16 ionotropic glutamate receptor subunits, eight metabotropic glutamate receptor subtypes, 21 ionotropic and two metabotropic GABA receptor subunits, some of which exist in alternatively splice variants, has enriched our appreciation of how molecular diversity leads to functional diversity in the brain. It now appears that many different types of glutamate and GABA receptor subunits have prominent expression in the embryonic and/or postnatal brain, whereas others are mainly present in the adult brain. Although the significance of this differential expression of subunits is not fully understood, it appears that the change in subunit composition is essential for normal development in particular brain regions. This review focuses on emerging information relating to the expression and role of glutamatergic and GABAergic neurotransmitter receptors during prenatal and postnatal development.
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Affiliation(s)
- R Luján
- Facultad de Medicina and Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Campus Biosanitario, Avda. de Almansa s/n, 02006 Albacete, Spain.
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23
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Di Giorgi Gerevini VD, Caruso A, Cappuccio I, Ricci Vitiani L, Romeo S, Della Rocca C, Gradini R, Melchiorri D, Nicoletti F. The mGlu5 metabotropic glutamate receptor is expressed in zones of active neurogenesis of the embryonic and postnatal brain. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2004; 150:17-22. [PMID: 15126034 DOI: 10.1016/j.devbrainres.2004.02.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/19/2004] [Indexed: 11/21/2022]
Abstract
Metabotropic glutamate (mGlu) receptors have been implicated in the regulation of developmental plasticity. Here, we examined the expression of mGlu1a-b, -2, -3, -4a-b, and -5a receptor subtypes from embryonic day 12 (E12) to the early and late postnatal life. While all transcripts (with the exception of mGlu4 mRNA) were detected prenatally, only the mGlu5 receptor protein was found in detectable amounts in the embryonic brain. Immunohistochemical analysis showed that the mGlu5 receptor was mainly expressed by cells surrounding the ventricles at E15, whereas it was more diffusely expressed at E18. In the postnatal life, besides its classical expression sites, the mGlu5 receptor was found in zones of active neurogenesis such as the external granular layer (EGL) of the cerebellar cortex and the subventricular zone. In these regions, the presence of actively proliferating progenitor cells was detected by BrdU staining. No other subtype (among those we have examined) was found to be expressed in regions enriched of BrdU(+) cells. These data suggest a role for mGlu5 receptors in the early brain development and in basic cellular processes such as proliferation and/or differentiation.
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Affiliation(s)
- V D Di Giorgi Gerevini
- Department of Human Physiology, University of Rome "La Sapienza", Piazzale Aldo Moro 5, 00195 Rome, Italy.
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24
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McQuillen PS, Ferriero DM. Selective vulnerability in the developing central nervous system. Pediatr Neurol 2004; 30:227-35. [PMID: 15087099 DOI: 10.1016/j.pediatrneurol.2003.10.001] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2003] [Accepted: 10/06/2003] [Indexed: 11/22/2022]
Abstract
Selective patterns of cerebral injury are observed after a variety of insults at different ages during development. Distinct populations of cells demonstrate selective vulnerability during these specific developmental stages, which may account for the observed patterns of injury. We review the evidence that injury to preoligodendrocytes and subplate neurons contributes to periventricular white matter injury in preterm infants, whereas thalamic neuronal cell vulnerability and neuronal nitric oxide synthase-expressing striatal interneurons resistance result in deep gray nuclei damage in the term infant. The unique roles of particular mechanisms including oxidative stress, glutamatergic neurotransmission, and programmed cell death are discussed in the context of this selective vulnerability.
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Affiliation(s)
- Patrick S McQuillen
- Department of Pediatrics, University of California San Francisco Medical Center, San Francisco, California 94143-0106, USA
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25
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Gallyas F, Ball SM, Molnar E. Assembly and cell surface expression of KA-2 subunit-containing kainate receptors. J Neurochem 2003; 86:1414-27. [PMID: 12950450 DOI: 10.1046/j.1471-4159.2003.01945.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Kainate receptors (KARs) modulate synaptic transmission at both pre-synaptic and post-synaptic sites. The overlap in the distribution of KA-2 and GluR6/7 subunits in several brain regions suggests the co-assembly of these subunits in native KARs. The molecular mechanisms that control the assembly and surface expression of KARs are unknown. Unlike GluR5-7, the KA-2 subunit is unable to form functional homomeric KAR channels. We expressed the KA-2 subunit alone or in combination with other KAR subunits in HEK-293 cells. The cell surface expression of the KAR subunit homo- and heteromers were analysed using biotinylation and agonist-stimulated cobalt uptake. While GluR6 or GluR7 homomers were expressed on the cell surface, KA-2 alone was retained within the endoplasmic reticulum. We found that the cell surface expression of KA-2 was dramatically increased by co-expression with either of the low-affinity KAR subunits GluR5-7. However, co-expression with other related ionotropic glutamate receptor subunits (GluR1 and NR1) does not facilitate the cell surface expression of KA-2. The analysis of subcellular fractions of neocortex revealed that synaptic KARs have a relatively high KA-2 content compared to microsomal ones. Thus, KA-2 is likely to contain an endoplasmic reticulum retention signal that is shielded on assembly with other KAR subunits.
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Affiliation(s)
- Ferenc Gallyas
- MRC Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, University of Bristol, Bristol, UK
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26
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Loeliger M, Watson CS, Reynolds JD, Penning DH, Harding R, Bocking AD, Rees SM. Extracellular glutamate levels and neuropathology in cerebral white matter following repeated umbilical cord occlusion in the near term fetal sheep. Neuroscience 2003; 116:705-14. [PMID: 12573713 DOI: 10.1016/s0306-4522(02)00756-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Umbilical cord occlusion causes fetal hypoxemia which can result in brain injury including damage to cerebral white matter. Excessive glutamate release may be involved in the damage process. This study examined the relation between extracellular glutamate levels in the cerebral white matter of the ovine fetus during and after intermittent umbilical cord occlusion and the degree of resultant fetal brain injury. Fetal sheep underwent surgery for chronic catheterisation and implantation of an intra-cerebral microdialysis probe at 130 days of gestation (term approximately 147 days). Four days after surgery (day 1), seven fetuses were subjected to 5x2 min umbilical cord occlusions, and on the following day (day 2) they were subjected to either 4 or 5x4 min umbilical cord occlusions; seven fetuses served as controls. Microdialysis samples were collected before, during and after the umbilical cord occlusions to determine extracellular glutamate levels in the cerebral white matter. Fetal blood gas status was measured and the fetal electrocorticogram was recorded continuously. During the periods of umbilical cord occlusions on both days 1 and 2, fetal arterial oxygen saturation, arterial partial pressure of oxygen and arterial pH decreased (P<0.05) while arterial partial pressure of carbon dioxide increased (P<0.05). All fetuses showed episodes of isoelectric electrocortical activity during umbilical cord occlusions on both days 1 and 2. In fetuses with patent microdialysis probes there were marked increases of glutamate efflux in the cerebral white matter following umbilical cord occlusion. Fetal brains were removed at autopsy on day 5 and subjected to histological assessment. Brain damage was observed in all fetuses exposed to cord occlusion, particularly in the periventricular white matter, with the most extensive damage occurring in the fetuses with the greatest increases in glutamate levels. We conclude that, in the unanesthetised fetus in utero, glutamatergic processes are associated with umbilical cord occlusion-induced brain damage in the cerebral white matter.
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Affiliation(s)
- M Loeliger
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, 3010, Victoria, Australia.
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27
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Lee YH, Lin CH, Hsu LW, Hu SY, Hsiao WT, Ho YS. Roles of ionotropic glutamate receptors in early developing neurons derived from the P19 mouse cell line. J Biomed Sci 2003; 10:199-207. [PMID: 12595756 DOI: 10.1007/bf02256055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2002] [Accepted: 10/04/2002] [Indexed: 11/28/2022] Open
Abstract
We cultured a P19 mouse teratocarcinoma cell line and induced its neuronal differentiation to study the function of ionotropic glutamate receptors (GluRs) in early neuronal development. Immunocytochemical studies showed 85% neuronal population at 5 days in vitro (DIV) with microtubule-associated protein 2-positive staining. Thirty percent and 50% of the cells expressed the alpha-amino-3-hydroxy-5-methyl-4-isopropinonate (AMPA) receptor subunit, GluR2/3, and the kainate (kainic acid; KA) receptor subunit, GluR5/6/7, respectively. In Western blot analysis, the temporal expression of GluR2/3 began to appear at 3 DIV, whereas GluR5/6/7 was already expressed in the undifferentiated cells. P19-derived neurons began to respond to glutamate, AMPA and KA, but not to the metabotropic GluR agonist trans-1-aminocyclopentane-1,3-decarboxylic acid, by 5 DIV in terms of increases in intracellular calcium and phospholipase C-mediated poly-phosphoinositide turnover. Furthermore, KA reduced cell death of P19-derived neurons in both atmospheric and hypobaric conditions in a phospholipase C-dependent manner. The common AMPA/KA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, but not the AMPA receptor antagonist, 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide disodium, profoundly increased hypobaric insult-induced neurotoxicity. In a flow cytometry study, the nerve growth factor-mediated antiapoptotic effect was facilitated by AMPA, with an induction of TrkA, but not p75(NTR) expression. Therefore, AMPA and KA receptors might mediate neurotrophic functions to facilitate neurotrophic factor signaling to protect neurons against hypoxic insult in early neuronal development.
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MESH Headings
- Animals
- Apoptosis
- Blotting, Western
- Calcium/metabolism
- Carrier Proteins/metabolism
- Cell Cycle
- Cell Differentiation
- Cell Line
- Cell Line, Tumor
- Cycloleucine/chemistry
- Dose-Response Relationship, Drug
- Flow Cytometry
- Hypoxia
- Immunohistochemistry
- Kainic Acid/metabolism
- Membrane Proteins/metabolism
- Mice
- Microscopy, Phase-Contrast
- Neurons/cytology
- Neurons/metabolism
- Phosphatidylinositols/chemistry
- Receptor, Nerve Growth Factor
- Receptor, trkA
- Receptors, AMPA/chemistry
- Receptors, AMPA/physiology
- Receptors, Kainic Acid/physiology
- Receptors, Nerve Growth Factor/chemistry
- Time Factors
- GluK2 Kainate Receptor
- GluK3 Kainate Receptor
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Affiliation(s)
- Yi-Hsuan Lee
- Department of Physiology, Taipei Medical University, Taipei, Taiwan, ROC.
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28
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Bandrowski AE, Huguenard JR, Prince DA. Baseline glutamate levels affect group I and II mGluRs in layer V pyramidal neurons of rat sensorimotor cortex. J Neurophysiol 2003; 89:1308-16. [PMID: 12626613 PMCID: PMC3005275 DOI: 10.1152/jn.00644.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Possible functional roles for glutamate that is detectable at low concentrations in the extracellular space of intact brain and brain slices have not been explored. To determine whether this endogenous glutamate acts on metabotropic glutamate receptors (mGluRs), we obtained whole cell recordings from layer V pyramidal neurons of rat sensorimotor cortical slices. Blockade of mGluRs with (+)-alpha-amino-4-carboxy-alpha-methyl-benzeacetic acid (MCPG, a general mGluR antagonist) increased the mean amplitude of spontaneous excitatory postsynaptic currents (sEPSCs), an effect attributable to a selective increase in the occurrence of large amplitude sEPSCs. 2S-2-amino-2-(1S,2S-2-carboxycyclopropyl-1-yl)-3-(xanth-9-yl)propanoic acid (LY341495, a group II antagonist) increased, but R(-)-1-amino-2,3-dihydro-1H-indene-1,5-dicarboxylic acid (AIDA) and (RS)-hexyl-HIBO (group I antagonists) decreased sEPSC amplitude, and (R,S)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG, a group III antagonist) did not change it. The change in sEPSCs elicited by MCPG, AIDA, and LY341495 was absent in tetrodotoxin, suggesting that it was action potential-dependent. The increase in sEPSCs persisted in GABA receptor antagonists, indicating that it was not due to effects on inhibitory interneurons. AIDA and (S)-3,5-dihydroxyphenylglycine (DHPG, a group I agonist) elicited positive and negative shifts in holding current, respectively. LY341495 and (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV, a group II agonist) elicited negative and positive shifts in holding current, respectively. The AIDA and LY341495 elicited currents persisted in TTX. Finally, in current clamp, LY341495 depolarized cells by approximately 2 mV and increased the number of action potentials to a given depolarizing current pulse. Thus ambient levels of glutamate tonically activate mGluRs and regulate cortical excitability.
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Affiliation(s)
- A E Bandrowski
- Department of Neurology, Stanford University Medical Center, Stanford, California 94305, USA
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Duncan JR, Cock ML, Scheerlinck JPY, Westcott KT, McLean C, Harding R, Rees SM. White matter injury after repeated endotoxin exposure in the preterm ovine fetus. Pediatr Res 2002; 52:941-9. [PMID: 12438674 DOI: 10.1203/00006450-200212000-00021] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Intrauterine infection has been linked to neurologic injury in preterm infants. However, a reproducible model of white matter injury in the preterm fetus in a long gestation species that can be monitored in utero is currently unavailable. Thus, our objective was to determine the effects of bacterial endotoxin (lipopolysaccharide, LPS) on physiologic and inflammatory responses and brain structure in the preterm ovine fetus. At 0.7 of gestation, six catheterized fetuses received three to five intravenous injections of LPS (1 micro g/kg) over 5 d; seven fetuses served as controls. Fetal responses were monitored and brain tissue examined 10-11 d after the initial LPS injection. After LPS on d 1 and 2, fetuses became transiently hypoxemic and hypotensive and blood IL-6 levels were increased, but these responses were smaller or absent after subsequent LPS exposures. Neural injury was observed in all LPS-exposed fetuses, most prominently in the cerebral white matter. Injury ranged from diffuse subcortical damage to periventricular leukomalacia, and in the brainstem the cross-sectional area of the corticospinal tract was reduced by 30%. Thus, repeated exposure of the preterm ovine fetus to LPS causes neuropathology resembling that of cerebral palsy and provides a robust model for exploring the etiology, prevention, and treatment of white matter damage.
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Affiliation(s)
- Jhodie R Duncan
- Department of Anatomy and Cell Biology, University of Melbourne, Melbourne, Victoria, Australia.
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Aizenman CD, Muñoz-Elías G, Cline HT. Visually driven modulation of glutamatergic synaptic transmission is mediated by the regulation of intracellular polyamines. Neuron 2002; 34:623-34. [PMID: 12062045 DOI: 10.1016/s0896-6273(02)00674-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Ca2+-permeable AMPARs are inwardly rectifying due to block by intracellular polyamines. Neuronal activity regulates polyamine synthesis, yet whether this affects Ca2+-AMPAR-mediated synaptic transmission is unknown. We test whether 4 hr of increased visual stimulation regulates glutamatergic retino-tectal synapses in Xenopus tadpoles. Tectal neurons containing Ca2+-AMPARs form a gradient along the rostro-caudal developmental axis. These neurons had inwardly rectifying AMPAR-mediated EPSCs. Four hours of visual stimulation or addition of intracellular spermine increased rectification in immature neurons. Polyamine synthesis inhibitors blocked the effect of visual stimulation, suggesting that visual activity regulates AMPARs via the polyamine synthesis pathway. This modulation resulted in changes in the integrative properties of tectal neurons. Regulation of polyamine synthesis by physiological stimuli is a novel form of modulation of synaptic transmission important for understanding the short-term effects of enhanced sensory experience during development.
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Affiliation(s)
- Carlos D Aizenman
- Cold Spring Harbor Laboratory, Beckman Building, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA
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Lesuisse C, Martin LJ. Long-term culture of mouse cortical neurons as a model for neuronal development, aging, and death. JOURNAL OF NEUROBIOLOGY 2002; 51:9-23. [PMID: 11920724 DOI: 10.1002/neu.10037] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A long-term cell culture system was used to study maturation, aging, and death of cortical neurons. Mouse cortical neurons were maintained in culture in serum-free medium (Neurobasal supplemented with B27) for 60 days in vitro (DIV). The levels of several proteins were evaluated by immunoblotting to demonstrate that these neurons matured by developing dendrites and synapses and remained continuously healthy for 60 DIV. During their maturation, cortical neurons showed increased or stable protein expression of glycolytic enzyme, synaptophysin, synapsin IIa, alpha and beta synucleins, and glutamate receptors. Synaptogenesis was prominent during the first 15 days and then synaptic markers remained stable through DIV60. Very early during dendritic development at DIV3, beta-synuclein (but not alpha-synuclein) was localized at the base of dendritic growth cones identified by MAP2 and alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) receptor GluR1. In mature neurons, alpha and beta synucleins colocalized in presynaptic axon terminals. Expression of N-methyl-D-aspartate (NMDA) and AMPA receptors preceded the formation of synapses. Glutamate receptors continued to be expressed strongly through DIV60. Cortical neurons aging in vitro displayed a complex profile of protein damage as identified by protein nitration. During cortical neuron aging, some proteins showed increased nitration, while other proteins showed decreased nitration. After exposure to DNA damaging agent, young (DIV5) and old (DIV60) cortical neurons activated apoptosis mechanisms, including caspase-3 cleavage and poly(ADP)-ribose polymerase inactivation. We show that cultured mouse cortical neurons can be maintained for long term. Cortical neurons display compartmental changes in the localization of synucleins during maturation in vitro. These neurons sustain protein nitration during aging and exhibit age-related variations in the biochemistry of neuronal apoptosis.
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Affiliation(s)
- Christian Lesuisse
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Quartu M, Serra MP, Ambu R, Lai ML, Del Fiacco M. AMPA-type glutamate receptor subunits 2/3 in the human trigeminal sensory ganglion and subnucleus caudalis from prenatal ages to adulthood. Mech Ageing Dev 2002; 123:463-71. [PMID: 11796131 DOI: 10.1016/s0047-6374(01)00358-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Using immunohistochemistry, the occurrence and distribution of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) glutamate receptor subunits GluR2/3 is shown in the human trigeminal ganglion and subnucleus caudalis from 20 weeks of gestation to adulthood. In the trigeminal ganglion a subpopulation of GluR2/3-like immunoreactive (LI) primary sensory neurons occurred at all examined ages, amounting to about 20% of all ganglion cells in the earliest pre-term newborn and in the adult, to about 30% at 24 and 32 weeks of gestation, and peaking to about 40% in the neonate. At all ages examined, GluR2/3-LI neurons were heterogeneous in size, although in the adult most of the labeled perikarya were large-sized, with a mean cell diameter above 35 microm. In the trigeminal subnucleus caudalis, positive elements could be first detected at 30 weeks of gestation and persisted at all other examined ages. At pre- and perinatal ages, the immunoreactivity was restricted to neuronal perikarya in the superficial layers and in the marginal zone of the nucleus. In the adult tissue, the subnucleus caudalis harbored a loose meshwork of varicose thread- and dot-like elements in the superficial layers and numerous immunoreactive neurons, distributed in lamina I, substantia gelatinosa, and in the superficial zone of the magnocellular region.
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Affiliation(s)
- Marina Quartu
- Dipartimento di Citomorfologia, Università di Cagliari, Cittadella Universitaria di Monserrato, Cagliari, Italy.
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Sinakevitch I, Farris SM, Strausfeld NJ. Taurine-, aspartate- and glutamate-like immunoreactivity identifies chemically distinct subdivisions of Kenyon cells in the cockroach mushroom body. J Comp Neurol 2001; 439:352-67. [PMID: 11596059 DOI: 10.1002/cne.1355] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The lobes of the mushroom bodies of the cockroach Periplaneta americana consist of longitudinal modules called laminae. These comprise repeating arrangements of Kenyon cell axons, which like their dendrites and perikarya have an affinity to one of three antisera: to taurine, aspartate, or glutamate. Taurine-immunopositive laminae alternate with immunonegative ones. Aspartate-immunopositive Kenyon cell axons are distributed across the lobes. However, smaller leaf-like ensembles of axons that reveal particularly high affinities to anti-aspartate are embedded within taurine-positive laminae and occur in the immunonegative laminae between them. Together, these arrangements reveal a complex architecture of repeating subunits whose different levels of immunoreactivity correspond to broader immunoreactive layers identified by sera against the neuromodulator FMRFamide. Throughout development and in the adult, the most posterior lamina is glutamate immunopositive. Its axons arise from the most recently born Kenyon cells that in the adult retain their juvenile character, sending a dense system of collaterals to the front of the lobes. Glutamate-positive processes intersect aspartate- and taurine-immunopositive laminae and are disposed such that they might play important roles in synaptogenesis or synapse modification. Glutamate immunoreactivity is not seen in older, mature axons, indicating that Kenyon cells show plasticity of neurotransmitter phenotype during development. Aspartate may be a universal transmitter substance throughout the lobes. High levels of taurine immunoreactivity occur in broad laminae containing the high concentrations of synaptic vesicles.
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Affiliation(s)
- I Sinakevitch
- Arizona Research Laboratories Division of Neurobiology University of Arizona, Tucson, 85721, USA.
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Mion S, Corti C, Neki A, Shigemoto R, Corsi M, Fumagalli G, Ferraguti F. Bidirectional regulation of neurite elaboration by alternatively spliced metabotropic glutamate receptor 5 (mGluR5) isoforms. Mol Cell Neurosci 2001; 17:957-72. [PMID: 11414786 DOI: 10.1006/mcne.2001.0993] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alternative splicing in the mGluR5 gene generates two different receptor isoforms, of which expression is developmentally regulated. However, little is known about the functional significance of mGluR5 splice variants. We have examined the functional coupling, subcellular targeting, and effect on neuronal differentiation of epitope-tagged mGluR5 isoforms by expression in neuroblastoma NG108-15 cells. We found that both mGluR5 splice variants give rise to comparable [Ca2+]i transients and have similar pharmacological profile. Tagged receptors were shown by immunofluorescence to be inserted in the plasma membrane. In undifferentiated cells the subcellular localization of the two mGluR5 isoforms was partially segregated, whereas in differentiated cells the labeling largely redistributed to the newly formed neurites. Interestingly, we demonstrate that mGluR5 splice variants dramatically influence the formation and maturation of neurites; mGluR5a hinders the acquisition of mature neuronal traits and mGluR5b fosters the elaboration and extension of neurites. These effects are partly inhibited by MPEP.
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Affiliation(s)
- S Mion
- Department of Medicine and Public Health, Pharmacology Section, Universita' di Verona, Policlinico Borgo Roma, Verona, 37134, Italy
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Ritter LM, Unis AS, Meador-Woodruff JH. Ontogeny of ionotropic glutamate receptor expression in human fetal brain. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2001; 127:123-33. [PMID: 11334999 DOI: 10.1016/s0165-3806(01)00126-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Glutamate receptors have multiple roles in the central nervous system. Recent evidence suggests that the iontropic glutamate receptors are critical during brain development, particularly for corticogenesis, neuronal migration, and synaptogenesis. In this study, we examined subunit mRNA expression and binding sites of the NMDA, AMPA, and kainate receptors from gestational weeks 8-20 in human fetal brain. Expression of glutamate receptors was high during several periods in these brains. Different levels of expression of each NMDA, AMPA, and kainate receptor subunit transcripts were present during development, with a greater abundance of NR1, NR2B, NR2D, GluR7, and KA1 mRNA at most gestational ages. Binding sites for NMDA, AMPA, and kainate receptors were all detected, but each had a unique pattern of expression. These results demonstrate that glutamate receptors are expressed early in human brain development, and undergo complex changes over time consistent with their role in normal development.
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MESH Headings
- 2-Amino-5-phosphonovalerate/analogs & derivatives
- 2-Amino-5-phosphonovalerate/metabolism
- 2-Amino-5-phosphonovalerate/pharmacology
- Brain/embryology
- Brain/physiology
- Brain Chemistry/genetics
- Excitatory Amino Acid Agonists/metabolism
- Excitatory Amino Acid Agonists/pharmacology
- Excitatory Amino Acid Antagonists/metabolism
- Excitatory Amino Acid Antagonists/pharmacology
- Fetus/physiology
- Gene Expression Regulation, Developmental
- Humans
- Indoles/metabolism
- Indoles/pharmacology
- Kainic Acid/metabolism
- Kainic Acid/pharmacology
- Piperidines/metabolism
- Piperidines/pharmacology
- RNA, Messenger/analysis
- Radioligand Assay
- Receptors, AMPA/analysis
- Receptors, AMPA/genetics
- Receptors, Glutamate/analysis
- Receptors, Glutamate/genetics
- Receptors, Kainic Acid/analysis
- Receptors, Kainic Acid/genetics
- Receptors, N-Methyl-D-Aspartate/analysis
- Receptors, N-Methyl-D-Aspartate/genetics
- Tritium
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/metabolism
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
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Affiliation(s)
- L M Ritter
- Mental Health Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
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González-Burgos I, Pérez-Vega MI, Beas-Zárate C. Neonatal exposure to monosodium glutamate induces cell death and dendritic hypotrophy in rat prefrontocortical pyramidal neurons. Neurosci Lett 2001; 297:69-72. [PMID: 11121872 DOI: 10.1016/s0304-3940(00)01669-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Monosodium glutamate was administered subcutaneously to male neonate rats, and the effects on cell number and cytoarchitecture of third-layer pyramidal neurons from the prefrontal cerebral cortex were studied in the adult. Monosodium glutamate treatment (4 mg/g of body weight, on post-natal days 1, 3, 5 and 7) resulted in fewer neurons, and shorter and less ramified dendritic processes, than those observed in control animals. Both density and proportional shapes of dendritic spines were not modified. We propose a dual effect of neonatal exposure to glutamate: an excitotoxic effect leading to cell death, and; a secondary neuroprotective effect, arising from the proliferation of glial cells and their subsequent uptake of glutamate, that favors the survival of the remaining neurons, and leads to a further hypotrophic effect on their dendritic processes.
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Affiliation(s)
- I González-Burgos
- Laboratorio de Psicobiología, Centro de Investigación Biomédica de Michoacán, Instituto Mexicano del Seguro Social, A.P. 7-70, C.P. 58261, Morelia, Michoaoán, Mexico.
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Martin LJ, Brambrink AM, Price AC, Kaiser A, Agnew DM, Ichord RN, Traystman RJ. Neuronal death in newborn striatum after hypoxia-ischemia is necrosis and evolves with oxidative stress. Neurobiol Dis 2000; 7:169-91. [PMID: 10860783 DOI: 10.1006/nbdi.2000.0282] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanisms for neurodegeneration after hypoxia-ischemia (HI) in newborns are not understood. We tested the hypothesis that striatal neuron death is necrosis and evolves with oxidative stress and selective organelle damage. Piglets ( approximately 1 week old) were used in a model of hypoxia-asphyxia and survived for 3, 6, 12, or 24 h. Neuronal death was progressive over 3-24 h recovery, with approximately 80% of putaminal neurons dead at 24 h. Striatal DNA was digested randomly at 6-12 h. Ultrastructurally, dying neurons were necrotic. Damage to the Golgi apparatus and rough endoplasmic reticulum occurred at 3-12 h, while most mitochondria appeared intact until 12 h. Mitochondria showed early suppression of activity, then a transient burst of activity at 6 h, followed by mitochondrial failure (determined by cytochrome c oxidase assay). Cytochrome c was depleted at 6 h after HI and thereafter. Damage to lysosomes occurred within 3-6 h. By 3 h recovery, glutathione levels were reduced, and peroxynitrite-mediated oxidative damage to membrane proteins, determined by immunoblots for nitrotyrosine, occurred at 3-12 h. The Golgi apparatus and cytoskeleton were early targets for extensive tyrosine nitration. Striatal neurons also sustained hydroxyl radical damage to DNA and RNA within 6 h after HI. We conclude that early glutathione depletion and oxidative stress between 3 and 6 h reperfusion promote damage to membrane and cytoskeletal proteins, DNA and RNA, as well as damage to most organelles, thereby causing neuronal necrosis in the striatum of newborns after HI.
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Affiliation(s)
- L J Martin
- Department of Pathology, Division of Neuropathy, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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