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Aleithe S, Blietz A, Mages B, Hobusch C, Härtig W, Michalski D. Transcriptional Response and Morphological Features of the Neurovascular Unit and Associated Extracellular Matrix After Experimental Stroke in Mice. Mol Neurobiol 2019; 56:7631-7650. [PMID: 31089963 PMCID: PMC6815284 DOI: 10.1007/s12035-019-1604-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/10/2019] [Indexed: 12/18/2022]
Abstract
Experimental stroke studies yielded insights into single reactions of the neurovascular unit (NVU) and associated extracellular matrix (ECM). However, the extent of simultaneous processes caused by ischemia and their underlying transcriptional changes are still poorly understood. Strictly following the NVU and ECM concept, this study explored transcriptional responses of cellular and non-cellular components as well as their morphological characteristics following ischemia. Mice were subjected to 4 or 24 h of unilateral middle cerebral artery occlusion. In the neocortex and the striatum, cytoskeletal and glial elements as well as blood-brain barrier and ECM components were analyzed using real-time PCR. Western blot analyses allowed characterization of protein levels and multiple immunofluorescence labeling enabled morphological assessment. Out of 37 genes analyzed, the majority exhibited decreased mRNA levels in ischemic areas, while changes occurred as early as 4 h after ischemia. Down-regulated mRNA levels were predominantly localized in the neocortex, such as the structural elements α-catenin 2, N-cadherin, β-catenin 1, and βIII-tubulin, consistently decreasing 4 and 24 h after ischemia. However, a few genes, e.g., claudin-5 and Pcam1, exhibited increased mRNA levels after ischemia. For several components such as βIII-tubulin, N-cadherin, and β-catenin 1, matching transcriptional and immunofluorescence signals were obtained, whereas a few markers including neurofilaments exhibited opposite directions. In conclusion, the variety in gene regulation emphasizes the complexity of interactions within the ischemia-affected NVU and ECM. These data might help to focus future research on a set of highly sensitive elements, which might prospectively facilitate neuroprotective strategies beyond the traditional single target perspective.
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Affiliation(s)
- Susanne Aleithe
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany.
- University of Leipzig, Liebigstr. 19, 04103, Leipzig, Germany.
| | - Alexandra Blietz
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
- University of Leipzig, Liebigstr. 19, 04103, Leipzig, Germany
| | - Bianca Mages
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103, Leipzig, Germany
| | - Constance Hobusch
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103, Leipzig, Germany
| | - Wolfgang Härtig
- University of Leipzig, Liebigstr. 19, 04103, Leipzig, Germany
| | - Dominik Michalski
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103, Leipzig, Germany.
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Huo D, Sun L, Zhang L, Ru X, Liu S, Yang H. Metabolome responses of the sea cucumber Apostichopus japonicus to multiple environmental stresses: Heat and hypoxia. MARINE POLLUTION BULLETIN 2019; 138:407-420. [PMID: 30660290 DOI: 10.1016/j.marpolbul.2018.11.063] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/24/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Economically important marine organisms face severe environmental challenges, such as high temperature and low dissolved oxygen, from global climate change. Adverse environmental factors impact the survival and growth of economically important marine organisms, thereby negatively influencing the aquaculture industry. However, little is known about the responses of sea cucumbers to combined environmental co-stressors till now. In this study, ultra-performance liquid chromatography (UPLC) was utilized to obtain metabolic profiles of sea cucumbers. Changes in the concentrations of 84, 68, and 417 metabolites related to the responses of sea cucumbers to heat (26 °C), hypoxia (2 mg/L) and the combined stress, respectively, were observed and analyzed. Representative biomarkers were discussed in detail, including deltaline, fusarin C, halichondrin B and rapanone. The concentration of metabolites involved in the regulation of energy metabolism, including amino acid, carbohydrate and lipid metabolism were significantly changed, and the tricarboxylic acid (TCA)-cycle was significantly altered under heat plus hypoxia. We interpreted these changes partly as an adaptation mechanism in response to environmental stress. Based on the decreased accumulation of glutamine, we hypothesized that heat stress is the main factor that interferes with the process of glutamic acid-glutamine metabolism. The present study showed that combined environmental stressors have a more extensive impact on the metabolites of the respiratory tree in sea cucumbers than single stress. These results would facilitate further development of the sea cucumber as an echinoderm model to study mechanisms of response to adverse environments, as well as to help advance knowledge of the adaptation of marine organisms to global climate change.
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Affiliation(s)
- Da Huo
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Lina Sun
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Libin Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xiaoshang Ru
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Shilin Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Hongsheng Yang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
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Liu H, Guo Y, Yang T, Fan Z, Huang M, Liang S, Liu C. Intervention effect of gamma aminobutyric acid on anxiety behavior induced by phthalate (2-ethylhexyl ester) in rats. Int J Neurosci 2018; 128:928-934. [PMID: 29191066 DOI: 10.1080/00207454.2017.1405952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 10/21/2017] [Accepted: 11/11/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Di(2-ethylhexyl) phthalate (DEHP) is one of the most widely used phthalate esters. The application of DEHP has caused serious environmental pollution and posed a threat to human health. METHODS A total of 30 male Sprague-Dawley rats were randomly divided into control group, DEHP group (500 mg/kg DEHP), low GABA (Gama-aminobutyric acid) group (500 mg/kg DEHP and 1 mg/kg GABA), medium GABA group (500 mg/kg DEHP and 2 mg/kg GABA) and high GABA group (500 mg/kg DEHP and 4 mg/kg GABA). The interventions continued for 30 consecutive days. Open-field test and elevated plus-maze test were used to detect behavioral changes of rats before and after interventions. RESULTS The levels of nitric oxide and nitric oxide synthase in prefrontal cortex of rats were measured using enzyme-linked immunosorbent assay. DEHP and GABA treatment had no significant effects on the body weight of rats. GABA restored food utilization rate of rats impaired by DEHP to the level of healthy rats. According to open-field test and elevated plus-maze test, GABA alleviated the effects of DEHP on rat behaviors. Enzyme-linked immunosorbent assay showed that GABA was effective in reducing the levels of nitric oxide and nitric oxide synthase in rats treated with DEHP. CONCLUSION DEHP exposure induced anxiety in rats, which may be achieved through elevating nitric oxide and nitric oxide synthase levels in prefrontal cortex of rats. However, the effects caused by DEHP could be alleviated by GABA.
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Affiliation(s)
- Huan Liu
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
| | - Youting Guo
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
| | - Tongwang Yang
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
| | - Zhicheng Fan
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
| | - Minhao Huang
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
| | - Shuqin Liang
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
| | - Chunhong Liu
- a College of Food Science , South China Agricultural University , Guangzhou , P.R. China
- b Key Laboratory of Food Quality and Safety of Guangdong Province , South China Agricultural University , Guangzhou , P.R. China
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Li B, Fan Y, Li C, Zhao X, Liu K, Lin Y. Online Electrochemical Monitoring of Glucose in Rat Brain with Acanthosphere-like CuOOH Nanospheres-based Electrochemical Sensor as Non-enzymatic and O2
-independent Detector. ELECTROANAL 2018. [DOI: 10.1002/elan.201700574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Bo Li
- Department of Chemistry; Capital Normal University; Beijing 100048 China
| | - Yongzhao Fan
- Capital University of Physical Education and Sports; Beijing 100191 P. R. China
| | - Changqing Li
- Department of Chemistry; Capital Normal University; Beijing 100048 China
| | - Xu Zhao
- Department of Chemistry; Capital Normal University; Beijing 100048 China
| | - Kun Liu
- Capital University of Physical Education and Sports; Beijing 100191 P. R. China
| | - Yuqing Lin
- Department of Chemistry; Capital Normal University; Beijing 100048 China
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Millar LJ, Shi L, Hoerder-Suabedissen A, Molnár Z. Neonatal Hypoxia Ischaemia: Mechanisms, Models, and Therapeutic Challenges. Front Cell Neurosci 2017; 11:78. [PMID: 28533743 PMCID: PMC5420571 DOI: 10.3389/fncel.2017.00078] [Citation(s) in RCA: 207] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/07/2017] [Indexed: 12/11/2022] Open
Abstract
Neonatal hypoxia-ischaemia (HI) is the most common cause of death and disability in human neonates, and is often associated with persistent motor, sensory, and cognitive impairment. Improved intensive care technology has increased survival without preventing neurological disorder, increasing morbidity throughout the adult population. Early preventative or neuroprotective interventions have the potential to rescue brain development in neonates, yet only one therapeutic intervention is currently licensed for use in developed countries. Recent investigations of the transient cortical layer known as subplate, especially regarding subplate's secretory role, opens up a novel set of potential molecular modulators of neonatal HI injury. This review examines the biological mechanisms of human neonatal HI, discusses evidence for the relevance of subplate-secreted molecules to this condition, and evaluates available animal models. Neuroserpin, a neuronally released neuroprotective factor, is discussed as a case study for developing new potential pharmacological interventions for use post-ischaemic injury.
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Affiliation(s)
- Lancelot J. Millar
- Molnár Group, Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| | - Lei Shi
- Molnár Group, Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
- JNU-HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of Pharmacy, Jinan UniversityGuangzhou, China
| | | | - Zoltán Molnár
- Molnár Group, Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
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Livne-Bar I, Lam S, Chan D, Guo X, Askar I, Nahirnyj A, Flanagan JG, Sivak JM. Pharmacologic inhibition of reactive gliosis blocks TNF-α-mediated neuronal apoptosis. Cell Death Dis 2016; 7:e2386. [PMID: 27685630 PMCID: PMC5059876 DOI: 10.1038/cddis.2016.277] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 07/25/2016] [Accepted: 07/29/2016] [Indexed: 01/03/2023]
Abstract
Reactive gliosis is an early pathological feature common to most neurodegenerative diseases, yet its regulation and impact remain poorly understood. Normally astrocytes maintain a critical homeostatic balance. After stress or injury they undergo rapid parainflammatory activation, characterized by hypertrophy, and increased polymerization of type III intermediate filaments (IFs), particularly glial fibrillary acidic protein and vimentin. However, the consequences of IF dynamics in the adult CNS remains unclear, and no pharmacologic tools have been available to target this mechanism in vivo. The mammalian retina is an accessible model to study the regulation of astrocyte stress responses, and their influence on retinal neuronal homeostasis. In particular, our work and others have implicated p38 mitogen-activated protein kinase (MAPK) signaling as a key regulator of glutamate recycling, antioxidant activity and cytokine secretion by astrocytes and related Müller glia, with potent influences on neighboring neurons. Here we report experiments with the small molecule inhibitor, withaferin A (WFA), to specifically block type III IF dynamics in vivo. WFA was administered in a model of metabolic retinal injury induced by kainic acid, and in combination with a recent model of debridement-induced astrocyte reactivity. We show that WFA specifically targets IFs and reduces astrocyte and Müller glial reactivity in vivo. Inhibition of glial IF polymerization blocked p38 MAPK-dependent secretion of TNF-α, resulting in markedly reduced neuronal apoptosis. To our knowledge this is the first study to demonstrate that pharmacologic inhibition of IF dynamics in reactive glia protects neurons in vivo.
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Affiliation(s)
- Izhar Livne-Bar
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,School of Optometry, University of California at Berkeley, Berkeley, CA, USA
| | - Susy Lam
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Darren Chan
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxin Guo
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Idil Askar
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Adrian Nahirnyj
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - John G Flanagan
- School of Optometry, University of California at Berkeley, Berkeley, CA, USA
| | - Jeremy M Sivak
- Department of Vision Sciences, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
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7
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Hyperactivity and impaired attention in Gamma aminobutyric acid transporter subtype 1 gene knockout mice. Acta Neuropsychiatr 2015; 27:368-74. [PMID: 26072958 DOI: 10.1017/neu.2015.37] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVES Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioural disorder. It is conceivable that Gamma aminobutyric acid (GABA) neurotransmission is implicated in the pathophysiology of ADHD. This study investigated the effect of GABA transporter 1 (GAT-1) on the anxiety-like behaviours and cognitive function in knockout mice. METHODS In all, 20 adult male mice were divided into two groups: wild-type (WT) group and GAT-1-/- group. The open field test, elevated O-maze (EZM) and Morris water maze were used to evaluate behavioural traits relevant to ADHD. RESULTS Compared with WT mice, the GAT-1-/- mice travelled longer and displayed an enhanced kinematic velocity with the significant reduction of rest time in the open field test (p<0.05). The EZM showed that GAT-1-/- mice displayed a significant increase in total entries into the open sectors and the closed sectors compared with the WT mice. The WT mice showed shorter latencies after the training session (p<0.01), whereas the GAT-1-/- mice made no difference during probe test, the GAT-1-/- mice spent less time in the target quadrant (p<0.01). CONCLUSION Our results demonstrated that GAT-1-/- mice have phenotypes of hyperactivity, impaired sustained attention and learning deficiency, and the performance of GAT-1-/- mice is similar to ADHD symptoms. So, the study of the GAT-1-/- mice may provide new insights into the mechanisms and the discovery of novel therapeutics for the treatment of ADHD.
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Jeitner TM, Battaile K, Cooper AJL. Critical Evaluation of the Changes in Glutamine Synthetase Activity in Models of Cerebral Stroke. Neurochem Res 2015; 40:2544-56. [DOI: 10.1007/s11064-015-1667-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/14/2015] [Accepted: 05/20/2015] [Indexed: 01/04/2023]
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Chen X, You J, Suo Y, Fan B. Sensitive Determination of Taurine, -Aminobutyric Acid and Ornithine in Wolfberry Fruit and Cortex Lycii by HPLC with Fluorescence Detection and Online Mass Spectrometry Identification. J Chromatogr Sci 2014; 53:492-7. [DOI: 10.1093/chromsci/bmu072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Nahirnyj A, Livne-Bar I, Guo X, Sivak JM. ROS detoxification and proinflammatory cytokines are linked by p38 MAPK signaling in a model of mature astrocyte activation. PLoS One 2013; 8:e83049. [PMID: 24376630 PMCID: PMC3871647 DOI: 10.1371/journal.pone.0083049] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/08/2013] [Indexed: 01/10/2023] Open
Abstract
Astrocytes are the most abundant glial cell in the retinal nerve fiber layer (NFL) and optic nerve head (ONH), and perform essential roles in maintaining retinal ganglion cell (RGC) detoxification and homeostasis. Mature astrocytes are relatively quiescent, but rapidly undergo a phenotypic switch in response to insult, characterized by upregulation of intermediate filament proteins, loss of glutamate buffering, secretion of pro-inflammatory cytokines, and increased antioxidant production. These changes result in both positive and negative influences on RGCs. However, the mechanism regulating these responses is still unclear, and pharmacologic strategies to modulate select aspects of this switch have not been thoroughly explored. Here we describe a system for rapid culture of mature astrocytes from the adult rat retina that remain relatively quiescent, but respond robustly when challenged with oxidative damage, a key pathogenic stress associated with inner retinal injury. When primary astrocytes were exposed to reactive oxygen species (ROS) we consistently observed characteristic changes in activation markers, along with increased expression of detoxifying genes, and secretion of proinflammatory cytokines. This in vitro model was then used for a pilot chemical screen to target specific aspects of this switch. Increased activity of p38α and β Mitogen Activated Protein Kinases (MAPKs) were identified as a necessary signal regulating expression of MnSOD, and heme oxygenase 1 (HO-1), with consequent changes in ROS-mediated injury. Additionally, multiplex cytokine profiling detected p38 MAPK-dependent secretion of IL-6, MCP-1, and MIP-2α, which are proinflammatory signals recently implicated in damage to the inner retina. These data provide a mechanism to link increased oxidative stress to proinflammatory signaling by astrocytes, and establish this assay as a useful model to further dissect factors regulating the reactive switch.
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Affiliation(s)
- Adrian Nahirnyj
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Izhar Livne-Bar
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxin Guo
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jeremy M. Sivak
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Özel RE, Ispas C, Ganesana M, Leiter JC, Andreescu S. Glutamate oxidase biosensor based on mixed ceria and titania nanoparticles for the detection of glutamate in hypoxic environments. Biosens Bioelectron 2013; 52:397-402. [PMID: 24090755 DOI: 10.1016/j.bios.2013.08.054] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 11/26/2022]
Abstract
We report on the design and development of a glutamate oxidase (GmOx) microelectrode for measuring l-glutamic acid (GluA) in oxygen-depleted conditions, which is based on the oxygen storage and release capacity of cerium oxides. To fabricate the biosensor, a nanocomposite of oxygen-rich ceria and titania nanoparticles dispersed within a semi-permeable chitosan membrane was co-immobilized with the enzyme GmOx on the surface of a Pt microelectrode. The oxygen delivery capacity of the ceria nanoparticles embedded in a biocompatible chitosan matrix facilitated enzyme stabilization and operation in oxygen free conditions. GluA was measured by amperometry at a working potential of 0.6 V vs Ag/AgCl. Detection limits of 0.594 µM and 0.493 µM and a sensitivity of 793 pA/µM (RSD 3.49%, n=5) and 395 pA/µM (RSD 2.48%, n=5) were recorded in oxygenated and deoxygenated conditions, with response times of 2s and 5s, respectively. The biosensor had good operational stability and selectivity against common interfering substances. Operation of the biosensor was tested in cerebrospinal fluid. Preliminary in vivo recording in Sprague-Dawley rats to monitor GluA in the cortex during cerebral ischemia and reperfusion demonstrate a potential application of the biosensor in hypoxic conditions. This method provides a solution to ensure functionality of oxidoreductase enzymes in oxygen-free environments.
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Affiliation(s)
- Rıfat Emrah Özel
- Department of Chemistry and Biomolecular Science, Potsdam, NY 13699-5810, USA
| | - Cristina Ispas
- Department of Chemistry and Biomolecular Science, Potsdam, NY 13699-5810, USA
| | | | - J C Leiter
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756
| | - Silvana Andreescu
- Department of Chemistry and Biomolecular Science, Potsdam, NY 13699-5810, USA
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Yu J, Huang X, Wu Q, Wang J, Yu X, Zhao P. Effect of A(2A) receptor antagonist (SCH 442416) on the mRNA expression of glutamate aspartate transporter and glutamine synthetase in rat retinal Müller cells under hypoxic conditions in vitro. Exp Ther Med 2012; 3:803-806. [PMID: 22969972 DOI: 10.3892/etm.2012.486] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Accepted: 01/30/2012] [Indexed: 11/06/2022] Open
Abstract
The purpose of the present study was to investigate the effect of the A(2A) receptor antagonist (SCH 442416) on the mRNA expression of glutamate aspartate transporter (GLAST) and glutamine synthetase (GS) in rat retinal Müller cells under hypoxic conditions in vitro. Immunofluorescent staining of GS and GFAP was used for the identification of Müller cells. The GLAST and GS mRNA expression of Müller cells treated with 0.1, 1 and 10 μM SCH 442416 under hypoxic conditions was examined by real-time PCR. Müller cells increased the mRNA expression of GLAST under hypoxic conditions; those treated with 0.1 μM SCH 442416 showed a further significant increase in the mRNA expression of GLAST in vitro. Although the mRNA expression of GS was decreased under hypoxic conditions, the mRNA expression was increased when Müller cells were treated with 0.1 μM SCH 442416. A(2A) receptor antagonist increased the GLAST and GS expression of Müller cells and accelerated the clearance of extracellular glutamate under hypoxic conditions in vitro.
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Affiliation(s)
- Jun Yu
- Department of Ophthalmology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine
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Striatal GABA Receptor Alterations in Hypoxic Neonatal Rats: Role of Glucose, Oxygen and Epinephrine Treatment. Neurochem Res 2011; 37:629-38. [DOI: 10.1007/s11064-011-0654-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 11/03/2011] [Accepted: 11/08/2011] [Indexed: 12/18/2022]
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14
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Zhao L, Jiao Q, Chen X, Yang P, Zhao B, Zheng P, Liu Y. mGluR5 is involved in proliferation of rat neural progenitor cells exposed to hypoxia with activation of mitogen-activated protein kinase signaling pathway. J Neurosci Res 2011; 90:447-60. [PMID: 22034224 DOI: 10.1002/jnr.22751] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/22/2011] [Accepted: 06/28/2011] [Indexed: 11/08/2022]
Abstract
Hypoxia/ischemia induces proliferation of neural progenitor cells (NPCs) in rodent and human brain; however, the mechanisms remain unknown. We investigated the effects of metabotropic glutamate receptor 5 (mGluR5) on NPC proliferation under hypoxia, the expression of cyclin D1, and the activation of the mitogen-activated protein kinases (MAPKs) signaling pathway in cell culture. The results showed that hypoxia induced mGluR5 expression on NPCs in vitro. Under hypoxia, the mGluR5 agonists DHPG and CHPG significantly increased NPC proliferation in cell activity, diameter of neurospheres, bromodeoxyuridine (BrdU) incorporation and cell division, and expression of cyclin D1, with decreasing cell death. The mGluR5 siRNA and antagonist MPEP decreased the NPC proliferation and expression of cyclin D1, with increasing cell death. Phosphorylated JNK and ERK increased with the proliferation of NPCs after DHPG and CHPG treatment under hypoxia, while p-p38 level decreased. These results demonstrate that the expression of mGluR5 was upregulated during the proliferation of rat NPCs stimulated by hypoxia in vitro. The activation of the ERK and JNK signaling pathway and the expression of cyclin D1 were increased in this process. These finding suggest the involvement of mGluR5 in rat NPC proliferation and provide a target molecule in neural repair after ischemia/hypoxia injury of CNS.
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Affiliation(s)
- Lingyu Zhao
- Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Education Ministry, Xi'an Jiaotong University College of Medicine, Xi'an, China
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15
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The role of glia in neuronal recovery following anoxia: In vitro evidence of neuronal adaptation. Neurochem Int 2011; 58:665-75. [DOI: 10.1016/j.neuint.2011.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 01/31/2011] [Accepted: 02/03/2011] [Indexed: 11/23/2022]
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Lee A, Lingwood BE, Bjorkman ST, Miller SM, Poronnik P, Barnett NL, Colditz P, Pow DV. Rapid loss of glutamine synthetase from astrocytes in response to hypoxia: Implications for excitotoxicity. J Chem Neuroanat 2010; 39:211-20. [DOI: 10.1016/j.jchemneu.2009.12.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 11/20/2009] [Accepted: 12/13/2009] [Indexed: 12/23/2022]
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Gionfriddo JR, Freeman KS, Groth A, Scofield VL, Alyahya K, Madl JE. alpha-Luminol prevents decreases in glutamate, glutathione, and glutamine synthetase in the retinas of glaucomatous DBA/2J mice. Vet Ophthalmol 2009; 12:325-32. [PMID: 19751494 DOI: 10.1111/j.1463-5224.2009.00722.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To test the hypothesis that in DBA/2J mice, oxidative stress decreases glutamine synthetase (GS) levels resulting in a loss of neuronal glutamate and that the antioxidant alpha-luminol (GVT) decreases this stress and glutamate loss in some types of glaucoma. ANIMALS DBA/2J mice were separated into two groups, of which one was not treated, and the other treated with GVT in the drinking water. At 7 months of age, retinas were examined from five untreated DBA/2J mice, seven GVT-treated mice, and five C57BL/6 mice (negative controls). METHODS Serial 0.5 microm plastic sections were immunogold stained for glutamate, GS, and total glutathione, followed by image analysis for staining patterns and density. RESULTS Focal decreases in glutamate immunostaining were common in the inner nuclear layer (INL) of DBA/2J retinas, but not in C57BL/6 or GVT-treated DBA/2J retinas. Decreases in glutathione and GS immunostaining were found in DBA/2J retinal regions where neuronal glutamate immunostaining was reduced. Retinas from GVT-treated DBA/2J had no significant decreases in INL levels of glutamate, glutathione, or GS. CONCLUSIONS Retinas of dogs with primary glaucoma are reported to have focal depletion of neuronal glutamate. In DBA/2J mice, similar changes occur prior to the development of clinical disease. In these focal glutamate-depleted regions, levels of glutathione and GS are also reduced, consistent with the hypothesis that oxidative stress contributes to retinal changes in glaucoma. The ability of GVT, an antioxidant, to inhibit retinal abnormalities in DBA/2J mice provides further support for this hypothesis.
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Affiliation(s)
- Juliet R Gionfriddo
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, USA
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18
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Chen CT, Alyahya K, Gionfriddo JR, Dubielzig RR, Madl JE. Loss of glutamine synthetase immunoreactivity from the retina in canine primary glaucoma. Vet Ophthalmol 2008; 11:150-7. [DOI: 10.1111/j.1463-5224.2008.00581.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Falcão AS, Silva RFM, Fernandes A, Brito MA, Brites D. Influence of hypoxia and ischemia preconditioning on bilirubin damage to astrocytes. Brain Res 2007; 1149:191-9. [PMID: 17376407 DOI: 10.1016/j.brainres.2007.02.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 02/16/2007] [Accepted: 02/18/2007] [Indexed: 10/23/2022]
Abstract
Hypoxia-ischemia in the perinatal period is a common cause of neurologic disability in children and is often associated with neonatal morbidity and mortality. Another frequent condition of the newborn is hyperbilirubinemia and it is well known that deposition of unconjugated bilirubin (UCB) in the central nervous system can damage nerve cells and cause encephalopathy. Interestingly, some studies report the onset of cerebral hypoxia-ischemia as a risk factor for UCB encephalopathy, since that condition often precedes neonatal hyperbilirubinemia. However, the cellular mechanisms triggered by hypoxia-ischemia that may enforce UCB deleterious effects are not well elucidated. Therefore, we designed this study to investigate whether hypoxia (HP) or combined oxygen-glucose deprivation (OGD) followed by reoxygenation, modifies glial cell susceptibility to UCB injury. Thus, cultured astrocytes were exposed to HP or OGD for 4 h and returned to normoxic conditions for another 12 h prior to incubation with UCB for 4 h. HP and OGD effects in UCB toxicity were compared to normoxic conditions. Our results demonstrate that HP and OGD preconditioning increase the vulnerability of glial cells to UCB damage by enhancing some of the deleterious effects of UCB, namely cell death by both apoptosis and necrosis. This preconditioning also augments the UCB-induced stimulation of an inflammatory response by an effect that involves the activation of the nuclear factor kappaB activation. These findings provide a novel basis for the increased risk of brain damage in jaundiced newborns that were previously exposed to hypoxia or ischemia during the perinatal period, namely during delivery.
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Affiliation(s)
- Ana S Falcão
- Centro de Patogénese Molecular-UBMBE, Faculdade de Farmácia, University of Lisbon, Av. Forças Armadas, 1600-083 Lisboa, Portugal
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20
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Zhang JX, Lu XJ, Wang XC, Li W, Du JZ. Intermittent hypoxia impairs performance of adult mice in the two-way shuttle box but not in the Morris water maze. J Neurosci Res 2006; 84:228-35. [PMID: 16615076 DOI: 10.1002/jnr.20860] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We have previously found that neonatal intermittent hypobaric hypoxia exposure enhanced mouse spatial, but impaired associative, cognition. This study sought to investigate the effects of hypobaric hypoxia on adult mice cognition. Mice were exposed to 2, 5, 10, 15, or 25 days of intermittent hypoxia (IH; 4 hr/day) at 2 km (16.0% O2) or 5 km (10.8% O2) altitudes in a hypobaric chamber for the Morris water maze (MWM) test and exposed to IH for 2, 10, or 25 days for the shuttle-box test. Amino acid dynamics in vivo in the hippocampus and amygdala of mice exposed to 2 km hypoxia were analyzed by high-pressure liquid chromatography. The results in MWM task showed that IH-2d to -25d at 2 km or 5 km did not change the escape latencies of mice in the training test or the retention of platform in the probe test. In the shuttle-box task, however, IH-10d at 5 km significantly reduced mouse avoidances in the acquisition test on day 4, and IH-10d at 2 km reduced avoidances in the retention test; IH-25d at 5 km significantly reduced avoidances of mice throughout the acquisition days. Glutamate in the amygdala persisted in declining to 69% of baseline at 8 hr posthypoxia (P = 0.040 vs. GLU released during 30 min before hypoxia) during the posthypoxia stage. These results suggest that adult hypobaric IH impairs the hippocampal-independent, but not the hippocampal-dependent, task in mice. The different GLU releases in the hippocampus and amygdala in response to hypoxia are involved in the different behaviors.
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Affiliation(s)
- Jia-Xing Zhang
- Division of Neurobiology and Physiology, College of Life Sciences, Yuquan Campus, Zhejiang University, Hangzhou, China
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21
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Bull ND, Barnett NL. Retinal glutamate transporter activity persists under simulated ischemic conditions. J Neurosci Res 2005; 78:590-9. [PMID: 15468177 DOI: 10.1002/jnr.20301] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Elevated extracellular concentrations of the neurotransmitter glutamate are neurotoxic and directly contribute to CNS damage as a result of ischemic pathologies. However, the main contributors to this uncontrolled rise in glutamate are still unconfirmed. It has been reported that the reversal of high-affinity glutamate transporters is a significant contributing factor. Conversely, it has also been observed that these transporters continue to take up glutamate, albeit at a reduced saturation concentration, under ischemic conditions. We sought to determine whether glutamate transporters continue to remove glutamate from the extracellular space under ischemic conditions by pharmacologically modulating the activity of high-affinity retinal glutamate transporters during simulated ischemia in vitro. Retinal glutamate transporter activity was significantly reduced under these ischemic conditions. The suppression of retinal glutamate transporter activity, with the protein kinase C inhibitor chelerythrine, significantly reduced ischemic glutamate uptake and enhanced retinal neurodegeneration. These findings imply a limited but protective role for retinal glutamate transporters under certain ischemic conditions, suggesting that pharmacological enhancement of high-affinity glutamate transporter activity may reduce tissue damage and loss of function resulting from toxic extracellular glutamate concentrations.
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Affiliation(s)
- Natalie D Bull
- Vision, Touch and Hearing Research Centre, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia.
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22
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Tanguy A, Boutet I, Moraga D. Molecular characterization of the glutamine synthetase gene in the Pacific oyster Crassostrea gigas: expression study in response to xenobiotic exposure and developmental stage. ACTA ACUST UNITED AC 2005; 1681:116-25. [PMID: 15627503 DOI: 10.1016/j.bbaexp.2004.10.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 10/01/2004] [Accepted: 10/22/2004] [Indexed: 11/23/2022]
Abstract
In this study, we characterized the full-length cDNA and genomic sequence of the gene encoding cytosolic glutamine synthetase (CgGSII) in the Pacific oyster, Crassostrea gigas. A phylogenetic analysis of GS sequences showed that CgGS clustered with the invertebrate group as expected. We analyzed the expression of mRNA CgGSII using RT-PCR to follow the expression of this gene in gills and digestive gland of oysters exposed, under experimental conditions, to hypoxia and to several contaminants (hydrocarbons and two pesticide treatments, glyphosate and a mixture of atrazine, diuron and isoproturon). We also investigated the expression of CgGSII in different developmental stages of C. gigas. Our results show that CgGSII expression was highly regulated in xenobiotic-exposed oysters compared to the control for all the treatments. Likewise, CgGSII expression was highly regulated according to the developmental stage of C. gigas. Finally, use of CgGSII as a possible marker to monitor xenobiotic exposure in disturbed ecosystems is discussed.
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Affiliation(s)
- Arnaud Tanguy
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR-CNRS 6539, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Place Nicolas Copernic, 29280 Plouzané, France
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23
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Montes S, Alcaraz-Zubeldia M, Muriel P, Rios C. Role of manganese accumulation in increased brain glutamine of the cirrhotic rat. Neurochem Res 2003; 28:911-7. [PMID: 12718445 DOI: 10.1023/a:1023279527545] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cirrhosis promotes increases of both manganese and glutamine in brain. Manganese is a modulator and glutamine is the product of glutamine synthetase. This work studies the relationship between manganese and glutamine synthetase in a model of cirrhosis in the rat. We administered manganese (1 g/L) in the drinking water of sham-operated and bile-duct obstructed rats. We evaluated the manganese and glutamine accumulation and the glutamine synthetase activity in frontal cortex, striatum, and pallidum after 2, 4, and 6 weeks of biliary obstruction or sham surgery. Cirrhotic rats receiving manganese increased their brain content of metal about 400%-600% after 4 weeks of treatment (P < .05) and also remarkably accumulated glutamine through time in the three regions studied (P < .05 at week 6). Interestingly, bile-duct obstructed rats treated with manganese showed no effect on glutamine synthetase activity. Results from this study suggest that manganese induces increases of brain glutamine independently of its synthesis.
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Affiliation(s)
- Sergio Montes
- Departamento de Neuroquímica, Instituto Nacional de Neurología y, Neurocirugía "Manuel Velasco Suárez", Mexico
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24
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Parrot S, Cottet-Emard JM, Sauvinet V, Pequignot JM, Denoroy L. Effects of Acute Hypoxic Conditions on Extracellular Excitatory Amino Acids and Dopamine in the Striatum of Freely-moving Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 536:433-44. [PMID: 14635697 DOI: 10.1007/978-1-4419-9280-2_55] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Affiliation(s)
- Sandrine Parrot
- Laboratoire de Neuropharmacologie et Neurochimie, INSERM U512, Université Claude Bernard, Lyon, France
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25
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Abstract
We investigated the effect of hypoxia on glutamate metabolism and uptake in rat pheochromocytoma (PC12) cells. Various key enzymes relevant to glutamate production, metabolism and transport were coordinately regulated by hypoxia. PC12 cells express two glutamate-metabolizing enzymes, glutamine synthetase (GS) and glutamate decarboxylase (GAD), as well as the glutamate-producing enzyme, phosphate-activated glutaminase (PAG). Exposure to hypoxia (1% O(2)) for 6 h or longer increased expression of GS mRNA and protein and enhanced GS enzymatic activity. In contrast, hypoxia caused a significant decrease in expression of PAG mRNA and protein, and also decreased PAG activity. In addition, hypoxia led to an increase in GAD65 and GAD67 protein levels and GAD enzymatic activity. PC12 cells express three Na(+)-dependent glutamate transporters; EAAC1, GLT-1 and GLAST. Hypoxia increased EAAC1 and GLT-1 protein levels, but had no effect on GLAST. Chronic hypoxia significantly enhanced the Na(+)-dependent component of glutamate transport. Furthermore, chronic hypoxia decreased cellular content of glutamate, but increased that of glutamine. Taken together, the hypoxia-induced changes in enzymes related to glutamate metabolism and transport are consistent with a decrease in the extracellular concentration of glutamate. This may have a role in protecting PC12 cells from the cytotoxic effects of glutamate during chronic hypoxia.
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Affiliation(s)
- S Kobayashi
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH 45267, USA
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26
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Boksha IS, Tereshkina EB, Burbaeva GS. Glutamine synthetase and glutamine synthetase-like protein from human brain: purification and comparative characterization. J Neurochem 2000; 75:2574-82. [PMID: 11080211 DOI: 10.1046/j.1471-4159.2000.0752574.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glutamine synthetase (GS; EC 6.3.1.2), a key enzyme of glutamate metabolism, and another enzyme possessing high hydroxylamine-L-glutamine transferase activity comparable to that of GS and termed GS-like protein (GSLP) were purified from human brain concurrently. In two-dimensional electrophoresis, GS subunits migrate to at least six different positions (44 +/- 1 kDa, pl = 6. 4-6.7), whereas GSLP subunits migrate to at least four different positions (54 +/- 1 kDa, pl = 5.9-6.2). Dependences of enzymatic activity in the transferase reaction on concentrations of Mn(2+) and Mg(2+) for GS and GSLP are different. High immunological cross-reactivity between GS and GSLP was observed in ELISA. Nevertheless, antisera were raised to GS and GSLP, and a method was developed for the separate detection of GS and GSLP in brain extracts by enzyme-chemiluminescent amplified (ECL) immunoblotting. The distribution of GS and GSLP immunoreactivities between soluble protein and crude mitochondrial fractions indicates tighter association with the particulate fraction for GSLP than for GS. The results from activity measurements suggest that the hydroxylamine-L-glutamine transferase activity measured routinely in protein extracts from brain is the sum of GS and GSLP activities. Similarly, immunoreactivity evaluated by ELISA is a sum of immunoreactivities of GS and GSLP. The relative contributions of GS and GSLP to the total immunoreactivity can be evaluated by ECL-immunoblotting.
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Affiliation(s)
- I S Boksha
- Laboratory of Neurochemistry, Mental Health Research Center of Russian Academy of Medical Sciences, Moscow, Russia
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27
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Viu E, Zapata A, Capdevila J, Skolnick P, Trullas R. Glycine(B) receptor antagonists and partial agonists prevent memory deficits in inhibitory avoidance learning. Neurobiol Learn Mem 2000; 74:146-60. [PMID: 10933900 DOI: 10.1006/nlme.1999.3947] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of N-methyl-d-aspartate (NMDA) receptors has been hypothesized to mediate certain forms of learning and memory. This hypothesis is based on the ability of competitive and uncompetitive NMDA receptor antagonists to disrupt learning. We investigated the effects of glycine site antagonists and partial agonists on deficits of acquisition (learning) and consolidation (memory) in a single trial inhibitory avoidance learning paradigm. Posttraining administration of either hypoxia (exposure to 7% oxygen) or the convulsant drug pentylenetetrazole (PTZ) (45 mg/kg) to mice impaired consolidation without producing neuronal cell death. Pretreatment with the competitive glycine antagonist 7-chlorokynurenic acid (7KYN) and the glycine partial agonists 1-aminocyclopropanecarboxylic acid (ACPC) and (+)HA-966 prevented memory deficits induced by hypoxia and PTZ, but did not affect scopolamine-induced learning impairment. In addition, ACPC prevented consolidation deficits evoked by a nonexcitotoxic concentration of l-trans-pyrrolidine-2, 4-dicarboxylate, a competitive inhibitor of glutamate transport that increases extracellular levels of glutamate. Moreover, (+)HA-966, 7KYN, and ACPC facilitated both acquisition and consolidation of inhibitory avoidance training, an effect that was dose-dependent and reversed by glycine. These results indicate that memory deficits induced by both hypoxia and PTZ involve NMDA receptor activation. Furthermore, the present findings demonstrate that glycine site antagonists and partial agonists prevent memory deficits of inhibitory avoidance learning by affecting consolidation, but not acquisition processes.
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Affiliation(s)
- E Viu
- Neurobiology Unit, IIBB/IDIBAPS, CSIC, Rossello 161, 08034, Barcelona, Spain
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28
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Gidday JM, Shah AR, Maceren RG, Wang Q, Pelligrino DA, Holtzman DM, Park TS. Nitric oxide mediates cerebral ischemic tolerance in a neonatal rat model of hypoxic preconditioning. J Cereb Blood Flow Metab 1999; 19:331-40. [PMID: 10078885 DOI: 10.1097/00004647-199903000-00011] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Neuroprotection against cerebral ischemia can be realized if the brain is preconditioned by previous exposure to a brief period of sublethal ischemia. The present study was undertaken to test the hypothesis that nitric oxide (NO) produced from the neuronal isoform of NO synthase (NOS) serves as a necessary signal for establishing an ischemia-tolerant state in brain. A newborn rat model of hypoxic preconditioning was used, wherein exposure to sublethal hypoxia (8% oxygen) for 3 hours renders postnatal day (PND) 6 animals completely resistant to a cerebral hypoxic-ischemic insult imposed 24 hours later. Postnatal day 6 animals were treated 0.5 hour before preconditioning hypoxia with the nonselective NOS inhibitor L-nitroarginine (2 mg/kg intraperitoneally). This treatment, which resulted in a 67 to 81% inhibition of calcium-dependent constitutive NOS activity 0.5 to 3.5 hours after its administration, completely blocked preconditioning-induced protection. However, administration of the neuronal NOS inhibitor 7-nitroindazole (40 mg/kg intraperitoneally) before preconditioning hypoxia, which decreased constitutive brain NOS activity by 58 to 81%, was without effect on preconditioning-induced cerebroprotection, as was pretreatment with the inducible NOS inhibitor aminoguanidine (400 mg/kg intraperitoneally). The protective effects of preconditioning were also not blocked by treating animals with competitive [3-(2-carboxypiperazin-4-yl)propyl-1-phosphonate; 5 mg/kg intraperitoneally] or noncompetitive (MK-801; 1 mg/kg intraperitoneally) N-methyl-D-aspartate receptor antagonists prior to preconditioning hypoxia. These findings indicate that NO production and activity are critical to the induction of ischemic tolerance in this model. However, the results argue against the involvement of the neuronal NOS isoform, activated secondary to a hypoxia-induced stimulation of N-methyl-D-aspartate receptors, and against the involvement of the inducible NOS isoform, but rather suggest that NO produced by the endothelial NOS isoform is required to mediate this profound protective effect.
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Affiliation(s)
- J M Gidday
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Banno T, Kohno K. Conformational changes of the smooth endoplasmic reticulum are facilitated by L-glutamate and its receptors in rat Purkinje cells. J Comp Neurol 1998. [DOI: 10.1002/(sici)1096-9861(19981214)402:2<252::aid-cne9>3.0.co;2-u] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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30
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Otoya RE, Seltzer AM, Donoso AO. Acute and long-lasting effects of neonatal hypoxia on (+)-3-[125I]MK-801 binding to NMDA brain receptors. Exp Neurol 1997; 148:92-9. [PMID: 9400422 DOI: 10.1006/exnr.1997.6612] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The NMDA receptor subtype is the major excitatory mediator for glutamate neurotoxicity. To assess its participation in the noxious effects of postnatal hypoxia, we have characterized the binding of the ionophoric marker of NMDA receptor, dizocilpine (MK-801). Binding of (+)-3-[125I]MK-801 to NMDA brain receptors under nonequilibrium conditions was quantified by in vitro autoradiography in rats exposed to hypoxia induced by 93% N2/6.5% O2 exposure for 70 min on Postnatal Day 4. Acute and long-lasting effects were investigated at 4 h after injury and on Postnatal Day 40. At the acute stage, a transient decrease in binding was found in several specific brain areas, hypothalamus, amygdaloid nuclei, entorhinal cortex, perirhinal cortex, and hippocampus, and no differences were found in temporal cortex, thalamus, and geniculate nucleus, when compared to sham-treated animals. At this early age, there was no increase of binding when slices from both groups were incubated in the presence of glutamate and glycine (Glu/Gly), positive allosteric modulators of MK-801 binding. In the 40-day-old brains, the binding to the NMDA receptors of hypoxiatreated animals was not different with respect to controls in most of the areas studied, but the Glu/Gly stimulation of binding in hypoxic rats showed a reduced, or absent, response to the allosteric modulators. In contrast, control rats showed a remarkable increase of the specific binding induced by the presence of the modulators in the incubation buffer. Binding of (+)-3-[125I]MK-801 was also performed at a higher concentration to clarify whether the altered response to Glu/Gly may be due to differences in the number of channels; however, the density of NMDA receptors at this concentration was similar in both control and hypoxia-treated rats. We conclude that the effect of exposure of newborn rats to hypoxia can generate acute and long-lasting effects on the NMDA receptor. The deleterious action of this kind of noxa on the CNS could be exerted by interference with normal glutamatergic transmission and hence over normal growth and development.
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MESH Headings
- Acute Disease
- Animals
- Animals, Newborn
- Brain Chemistry
- Brain Damage, Chronic/etiology
- Brain Damage, Chronic/genetics
- Brain Damage, Chronic/metabolism
- Brain Damage, Chronic/pathology
- Dizocilpine Maleate/metabolism
- Excitatory Amino Acid Agonists/pharmacology
- Excitatory Amino Acid Antagonists/metabolism
- Glutamic Acid/pharmacology
- Glycine/pharmacology
- Hypoxia/complications
- Hypoxia/metabolism
- Hypoxia/pathology
- Hypoxia, Brain/etiology
- Hypoxia, Brain/genetics
- Hypoxia, Brain/metabolism
- Hypoxia, Brain/pathology
- Organ Specificity
- Protein Binding
- Rats
- Rats, Sprague-Dawley
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/metabolism
- Time Factors
- Up-Regulation
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Affiliation(s)
- R E Otoya
- Laboratorio de Investigaciones Cerebrales (LINCE), CRICYT-CONICET C.C. 425, Mendoza, Argentina.
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31
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Natarajan M, Wilkinson M. Recovery of hypothalamic NMDA-induced c-fos expression following neonatal glutamate (MSG) lesions. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1997; 102:97-104. [PMID: 9298238 DOI: 10.1016/s0165-3806(97)00086-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The neonatal brain is susceptible to neurotoxic insult. In a previous report we showed that a single neonatal injection of MSG, known to cause damage in the arcuate nucleus (ARC), induces a precocious yet otherwise normal puberty in female rats. We have examined this ability of the medial basal hypothalamus (MBH) to recover from an excitotoxic insult using the immediate-early gene c-fos as a developmental marker of ARC response to glutamate receptor stimulation with N-methyl-D-aspartate (NMDA). Groups of neonatal (postnatal day (PD) 2) pups were injected with MSG, then stimulated on subsequent days (PD 3-29) with NMDA, known to induce c-fos expression in ARC. Computer-assisted densitometry was used to quantify Fos-like immunoreactivity (FLI) profiles in ARC. Pups treated neonatally with saline (PD 2) showed a robust, age-specific expression of FLI in the ARC following NMDA treatment. The FLI response was absent in the days immediately following an MSG lesion but subsequently recovered up to 75% of maximum by PD 16. Almost full recovery was seen by PD 29. We also examined the ability of the ARC to recover following chronic MSG treatment (PD 2-8), known to induce extensive hypothalamic damage. These pups displayed an unusual response to subsequent NMDA injection, consisting of 5 min cycles of hyper- and hypoactivity. Stimulation with NMDA revealed only a 50% recovery of FLI even at PD 29. In both treatment groups (acute vs. chronic MSG) the zone of recovery (i.e., reappearance of FLI) was initiated close to the third ventricle and with time radiated towards the periphery of the ARC. Some cells which reacquired FLI in the ARC following lesions presented a highly irregular condensed nuclear morphology. We conclude that the recovery of hypothalamic function (i.e., onset of puberty) after a neonatal MSG lesion is coincident with the reappearance of a normal pattern of c-fos expression in response to NMDA stimulation.
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Affiliation(s)
- M Natarajan
- Department of Obstetrics and Gynaecology, IWK-Grace Health Centre, Halifax, NS, Canada
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