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Anilkumar U, Weisova P, Schmid J, Bernas T, Huber HJ, Düssmann H, Connolly NMC, Prehn JHM. Defining external factors that determine neuronal survival, apoptosis and necrosis during excitotoxic injury using a high content screening imaging platform. PLoS One 2017; 12:e0188343. [PMID: 29145487 PMCID: PMC5690623 DOI: 10.1371/journal.pone.0188343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/06/2017] [Indexed: 12/27/2022] Open
Abstract
Cell death induced by excessive glutamate receptor overactivation, excitotoxicity, has been implicated in several acute and chronic neurological disorders. While numerous studies have demonstrated the contribution of biochemically and genetically activated cell death pathways in excitotoxic injury, the factors mediating passive, excitotoxic necrosis are less thoroughly investigated. To address this question, we developed a high content screening (HCS) based assay to collect high volumes of quantitative cellular imaging data and elucidated the effects of intrinsic and external factors on excitotoxic necrosis and apoptosis. The analysis workflow consisted of robust nuclei segmentation, tracking and a classification algorithm, which enabled automated analysis of large amounts of data to identify and quantify viable, apoptotic and necrotic neuronal populations. We show that mouse cerebellar granule neurons plated at low or high density underwent significantly increased necrosis compared to neurons seeded at medium density. Increased extracellular Ca2+ sensitized neurons to glutamate-induced excitotoxicity, but surprisingly potentiated cell death mainly through apoptosis. We also demonstrate that inhibition of various cell death signaling pathways (including inhibition of calpain, PARP and AMPK activation) primarily reduced excitotoxic apoptosis. Excitotoxic necrosis instead increased with low extracellular glucose availability. Our study is the first of its kind to establish and implement a HCS based assay to investigate the contribution of external and intrinsic factors to excitotoxic apoptosis and necrosis.
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Affiliation(s)
- Ujval Anilkumar
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Petronela Weisova
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jasmin Schmid
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Tytus Bernas
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Heinrich J. Huber
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Heiko Düssmann
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Niamh M. C. Connolly
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jochen H. M. Prehn
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
- * E-mail:
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A Microfluidic Platform for the Characterisation of CNS Active Compounds. Sci Rep 2017; 7:15692. [PMID: 29146949 PMCID: PMC5691080 DOI: 10.1038/s41598-017-15950-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/03/2017] [Indexed: 01/19/2023] Open
Abstract
New in vitro technologies that assess neuronal excitability and the derived synaptic activity within a controlled microenvironment would be beneficial for the characterisation of compounds proposed to affect central nervous system (CNS) function. Here, a microfluidic system with computer controlled compound perfusion is presented that offers a novel methodology for the pharmacological profiling of CNS acting compounds based on calcium imaging readouts. Using this system, multiple applications of the excitatory amino acid glutamate (10 nM–1 mM) elicited reproducible and reversible transient increases in intracellular calcium, allowing the generation of a concentration response curve. In addition, the system allows pharmacological investigations to be performed as evidenced by application of glutamatergic receptor antagonists, reversibly inhibiting glutamate-induced increases in intracellular calcium. Importantly, repeated glutamate applications elicited significant increases in the synaptically driven activation of the adjacent, environmentally isolated neuronal network. Therefore, the proposed new methodology will enable neuropharmacological analysis of CNS active compounds whilst simultaneously determining their effect on synaptic connectivity.
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Yan Y, Shen FY, Agresti M, Zhang LL, Matloub HS, LoGiudice JA, Havlik R, Li J, Gu YD, Yan JG. Best time window for the use of calcium-modulating agents to improve functional recovery in injured peripheral nerves-An experiment in rats. J Neurosci Res 2017; 95:1786-1795. [PMID: 28052373 DOI: 10.1002/jnr.24009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/23/2016] [Accepted: 11/30/2016] [Indexed: 11/08/2022]
Abstract
Peripheral nerve injury can have a devastating effect on daily life. Calcium concentrations in nerve fibers drastically increase after nerve injury, and this activates downstream processes leading to neuron death. Our previous studies showed that calcium-modulating agents decrease calcium accumulation, which aids in regeneration of injured peripheral nerves; however, the optimal therapeutic window for this application has not yet been identified. In this study, we show that calcium clearance after nerve injury is positively correlated with functional recovery in rats suffering from a crushed sciatic nerve injury. After the nerve injury, calcium accumulation increased. Peak volume is from 2 to 8 weeks post injury; calcium accumulation then gradually decreased over the following 24-week period. The compound muscle action potential (CMAP) measurement from the extensor digitorum longus muscle recovered to nearly normal levels in 24 weeks. Simultaneously, real-time polymerase chain reaction results showed that upregulation of calcium-ATPase (a membrane protein that transports calcium out of nerve fibers) mRNA peaked at 12 weeks. These results suggest that without intervention, the peak in calcium-ATPase mRNA expression in the injured nerve occurs after the peak in calcium accumulation, and CMAP recovery continues beyond 24 weeks. Immediately using calcium-modulating agents after crushed nerve injury improved functional recovery. These studies suggest that a crucial time frame in which to initiate effective clinical approaches to accelerate calcium clearance and nerve regeneration would be prior to 2 weeks post injury. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yuhui Yan
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
| | - Feng-Yi Shen
- Froedtert Health-Community Memorial Hospital, Medical College of Wisconsin, Milwaukee
| | - Michael Agresti
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
| | - Lin-Ling Zhang
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
| | - Hani S Matloub
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
| | - John A LoGiudice
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
| | - Robert Havlik
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
| | - Jifeng Li
- Department of Hand Surgery, Huashan Hospital, Fudan University and Key Laboratory of Hand Reconstruction, Ministry of Health, Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, China
| | - Yu-Dong Gu
- Department of Hand Surgery, Huashan Hospital, Fudan University and Key Laboratory of Hand Reconstruction, Ministry of Health, Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, China
| | - Ji-Geng Yan
- Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee
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4
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Neuronal networks provide rapid neuroprotection against spreading toxicity. Sci Rep 2016; 6:33746. [PMID: 27650924 PMCID: PMC5030638 DOI: 10.1038/srep33746] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 09/01/2016] [Indexed: 11/08/2022] Open
Abstract
Acute secondary neuronal cell death, as seen in neurodegenerative disease, cerebral ischemia (stroke) and traumatic brain injury (TBI), drives spreading neurotoxicity into surrounding, undamaged, brain areas. This spreading toxicity occurs via two mechanisms, synaptic toxicity through hyperactivity, and excitotoxicity following the accumulation of extracellular glutamate. To date, there are no fast-acting therapeutic tools capable of terminating secondary spreading toxicity within a time frame relevant to the emergency treatment of stroke or TBI patients. Here, using hippocampal neurons (DIV 15-20) cultured in microfluidic devices in order to deliver a localized excitotoxic insult, we replicate secondary spreading toxicity and demonstrate that this process is driven by GluN2B receptors. In addition to the modeling of spreading toxicity, this approach has uncovered a previously unknown, fast acting, GluN2A-dependent neuroprotective signaling mechanism. This mechanism utilizes the innate capacity of surrounding neuronal networks to provide protection against both forms of spreading neuronal toxicity, synaptic hyperactivity and direct glutamate excitotoxicity. Importantly, network neuroprotection against spreading toxicity can be effectively stimulated after an excitotoxic insult has been delivered, and may identify a new therapeutic window to limit brain damage.
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Bok Is Not Pro-Apoptotic But Suppresses Poly ADP-Ribose Polymerase-Dependent Cell Death Pathways and Protects against Excitotoxic and Seizure-Induced Neuronal Injury. J Neurosci 2016; 36:4564-78. [PMID: 27098698 DOI: 10.1523/jneurosci.3780-15.2016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/07/2016] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Bok (Bcl-2-related ovarian killer) is a Bcl-2 family member that, because of its predicted structural homology to Bax and Bak, has been proposed to be a pro-apoptotic protein. In this study, we demonstrate that Bok is highly expressed in neurons of the mouse brain but that bok was not required for staurosporine-, proteasome inhibition-, or excitotoxicity-induced apoptosis of cultured cortical neurons. On the contrary, we found that bok-deficient neurons were more sensitive to oxygen/glucose deprivation-induced injury in vitro and seizure-induced neuronal injury in vivo Deletion of bok also increased staurosporine-, excitotoxicity-, and oxygen/glucose deprivation-induced cell death in bax-deficient neurons. Single-cell imaging demonstrated that bok-deficient neurons failed to maintain their neuronal Ca(2+)homeostasis in response to an excitotoxic stimulus; this was accompanied by a prolonged deregulation of mitochondrial bioenergetics.bok deficiency led to a specific reduction in neuronal Mcl-1 protein levels, and deregulation of both mitochondrial bioenergetics and Ca(2+)homeostasis was rescued by Mcl-1 overexpression. Detailed analysis of cell death pathways demonstrated the activation of poly ADP-ribose polymerase-dependent cell death in bok-deficient neurons. Collectively, our data demonstrate that Bok acts as a neuroprotective factor rather than a pro-death effector during Ca(2+)- and seizure-induced neuronal injury in vitro and in vivo SIGNIFICANCE STATEMENT Bcl-2 proteins are essential regulators of the mitochondrial apoptosis pathway. The Bcl-2 protein Bok is highly expressed in the CNS. Because of its sequence similarity to Bax and Bak, Bok has long been considered part of the pro-apoptotic Bax-like subfamily, but no studies have yet been performed in neurons to test this hypothesis. Our study provides important new insights into the functional role of Bok during neuronal apoptosis and specifically in the setting of Ca(2+)- and seizure-mediated neuronal injury. We show that Bok controls neuronal Ca(2+)homeostasis and bioenergetics and, contrary to previous assumptions, exerts neuroprotective activities in vitro and in vivo Our results demonstrate that Bok cannot be placed unambiguously into the Bax-like Bcl-2 subfamily of pro-apoptotic proteins.
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Computational Analysis of AMPK-Mediated Neuroprotection Suggests Acute Excitotoxic Bioenergetics and Glucose Dynamics Are Regulated by a Minimal Set of Critical Reactions. PLoS One 2016; 11:e0148326. [PMID: 26840769 PMCID: PMC4740490 DOI: 10.1371/journal.pone.0148326] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/15/2016] [Indexed: 11/22/2022] Open
Abstract
Loss of ionic homeostasis during excitotoxic stress depletes ATP levels and activates the AMP-activated protein kinase (AMPK), re-establishing energy production by increased expression of glucose transporters on the plasma membrane. Here, we develop a computational model to test whether this AMPK-mediated glucose import can rapidly restore ATP levels following a transient excitotoxic insult. We demonstrate that a highly compact model, comprising a minimal set of critical reactions, can closely resemble the rapid dynamics and cell-to-cell heterogeneity of ATP levels and AMPK activity, as confirmed by single-cell fluorescence microscopy in rat primary cerebellar neurons exposed to glutamate excitotoxicity. The model further correctly predicted an excitotoxicity-induced elevation of intracellular glucose, and well resembled the delayed recovery and cell-to-cell heterogeneity of experimentally measured glucose dynamics. The model also predicted necrotic bioenergetic collapse and altered calcium dynamics following more severe excitotoxic insults. In conclusion, our data suggest that a minimal set of critical reactions may determine the acute bioenergetic response to transient excitotoxicity and that an AMPK-mediated increase in intracellular glucose may be sufficient to rapidly recover ATP levels following an excitotoxic insult.
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Barbosa DJ, Capela JP, de Lourdes Bastos M, Carvalho F. In vitro models for neurotoxicology research. Toxicol Res (Camb) 2015; 4:801-842. [DOI: 10.1039/c4tx00043a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
Abstract
The nervous system has a highly complex organization, including many cell types with multiple functions, with an intricate anatomy and unique structural and functional characteristics; the study of its (dys)functionality following exposure to xenobiotics, neurotoxicology, constitutes an important issue in neurosciences.
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Affiliation(s)
- Daniel José Barbosa
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
| | - João Paulo Capela
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
| | - Maria de Lourdes Bastos
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
| | - Félix Carvalho
- REQUIMTE (Rede de Química e Tecnologia)
- Laboratório de Toxicologia
- Departamento de Ciências Biológicas
- Faculdade de Farmácia
- Universidade do Porto
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Weisová P, Alvarez SP, Kilbride SM, Anilkumar U, Baumann B, Jordán J, Bernas T, Huber HJ, Düssmann H, Prehn JHM. Latrepirdine is a potent activator of AMP-activated protein kinase and reduces neuronal excitability. Transl Psychiatry 2013; 3:e317. [PMID: 24150226 PMCID: PMC3818013 DOI: 10.1038/tp.2013.92] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/09/2013] [Indexed: 12/18/2022] Open
Abstract
Latrepirdine/Dimebon is a small-molecule compound with attributed neurocognitive-enhancing activities, which has recently been tested in clinical trials for the treatment of Alzheimer's and Huntington's disease. Latrepirdine has been suggested to be a neuroprotective agent that increases mitochondrial function, however the molecular mechanisms underlying these activities have remained elusive. We here demonstrate that latrepirdine, at (sub)nanomolar concentrations (0.1 nM), activates the energy sensor AMP-activated protein kinase (AMPK). Treatment of primary neurons with latrepirdine increased intracellular ATP levels and glucose transporter 3 translocation to the plasma membrane. Latrepirdine also increased mitochondrial uptake of the voltage-sensitive probe TMRM. Gene silencing of AMPKα or its upstream kinases, LKB1 and CaMKKβ, inhibited this effect. However, studies using the plasma membrane potential indicator DisBAC2(3) demonstrated that the effects of latrepirdine on TMRM uptake were largely mediated by plasma membrane hyperpolarization, precluding a purely 'mitochondrial' mechanism of action. In line with a stabilizing effect of latrepirdine on plasma membrane potential, pretreatment with latrepirdine reduced spontaneous Ca(2+) oscillations as well as glutamate-induced Ca(2+) increases in primary neurons, and protected neurons against glutamate toxicity. In conclusion, our experiments demonstrate that latrepirdine is a potent activator of AMPK, and suggest that one of the main pharmacological activities of latrepirdine is a reduction in neuronal excitability.
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Affiliation(s)
- P Weisová
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - S P Alvarez
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Dpto Ciencias Médicas-Farmacología, Faculdad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - S M Kilbride
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - U Anilkumar
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - B Baumann
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - J Jordán
- Dpto Ciencias Médicas-Farmacología, Faculdad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - T Bernas
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Institute of Experimental Biology PAS, Warsaw, Poland
| | - H J Huber
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - H Düssmann
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - J H M Prehn
- Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, Dublin, Ireland,Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin, 2, Ireland. E-mail:
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9
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The effect of calcium modulating agents on peripheral nerve recovery after crush. J Neurosci Methods 2013; 217:54-62. [DOI: 10.1016/j.jneumeth.2013.04.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 03/26/2013] [Accepted: 04/15/2013] [Indexed: 01/03/2023]
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Weisová P, Anilkumar U, Ryan C, Concannon CG, Prehn JH, Ward MW. ‘Mild mitochondrial uncoupling’ induced protection against neuronal excitotoxicity requires AMPK activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:744-53. [DOI: 10.1016/j.bbabio.2012.01.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/30/2012] [Accepted: 01/31/2012] [Indexed: 11/25/2022]
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Abstract
Excitotoxicity resulting from excessive Ca(2+) influx through glutamate receptors contributes to neuronal injury after stroke, trauma, and seizures. Increased cytosolic Ca(2+) levels activate a family of calcium-dependent proteases with papain-like activity, the calpains. Here we investigated the role of calpain activation during NMDA-induced excitotoxic injury in embryonic (E16-E18) murine cortical neurons that (1) underwent excitotoxic necrosis, characterized by immediate deregulation of Ca(2+) homeostasis, a persistent depolarization of mitochondrial membrane potential (Δψ(m)), and insensitivity to bax-gene deletion, (2) underwent excitotoxic apoptosis, characterized by recovery of NMDA-induced cytosolic Ca(2+) increases, sensitivity to bax gene deletion, and delayed Δψ(m) depolarization and Ca(2+) deregulation, or (3) that were tolerant to excitotoxic injury. Interestingly, treatment with the calpain inhibitor calpeptin, overexpression of the endogenous calpain inhibitor calpastatin, or gene silencing of calpain protected neurons against excitotoxic apoptosis but did not influence excitotoxic necrosis. Calpeptin failed to exert a protective effect in bax-deficient neurons but protected bid-deficient neurons similarly to wild-type cells. To identify when calpains became activated during excitotoxic apoptosis, we monitored calpain activation dynamics by time-lapse fluorescence microscopy using a calpain-sensitive Förster resonance energy transfer probe. We observed a delayed calpain activation that occurred downstream of mitochondrial engagement and directly preceded neuronal death. In contrast, we could not detect significant calpain activity during excitotoxic necrosis or in neurons that were tolerant to excitotoxic injury. Oxygen/glucose deprivation-induced injury in organotypic hippocampal slice cultures confirmed that calpains were specifically activated during bax-dependent apoptosis and in this setting function as downstream cell-death executioners.
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Ge QF, Zhang HY. [Effects of Chinese herbal medicines for regulating liver qi on expression of 5-hydroxytryptamine 3B receptor in hypothalamic tissues of rats with anger emotion]. ACTA ACUST UNITED AC 2011; 9:871-7. [PMID: 21849148 DOI: 10.3736/jcim20110809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To explore the central mechanisms of anger emotion and the effects of Chinese herbal medicines for regulating liver qi on the anger emotion and the expression level of 5-hydroxytryptamine 3B receptor (5-HT3BR) in rat hypothalamus. METHODS Rat models of anger-in or anger-out emotions were prepared by the methods of resident intruder paradigm. There were five groups in this study: control, anger-in model, Jingqianshu Granule-treated anger-in, anger-out model and Jingqianping Granule-treated anger-out groups. The treatment groups were orally given Jingqianshu granules and Jingqianping granules respectively, and the model groups and the normal control group were given sterile water. Open-field test and sucrose preference test were used to evaluate behavioristics of the rats. Semi-quantitative reverse transcription-polymerase chain reaction and Western blot methods were used to detect the expression levels of 5-HT3BR mRNA and protein in the rat hypothalamus. RESULTS The expression of 5-HT3BR in hypothalamus of anger-in model rats increased obviously (P<0.01) and that of anger-out model rats decreased obviously (P<0.01) compared with the normal control group. Compared with the model group, the expressions of 5-HT3BR in the treatment groups were significantly improved (P<0.01) after treatment, and recovered to normal level. CONCLUSION The anger-in stimulation obviously increases hypothalamic 5-HT3BR expression and the anger-out emotion can obviously reduce its expression. Chinese herbal medicines for regulating liver qi may treat anger emotion in rats by improving the hypothalamic 5-HT3BR protein and gene expression levels.
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Affiliation(s)
- Qing-fang Ge
- Key Laboratory of Classics Theory of Traditional Chinese Medicine of the Ministry of Education of China, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
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Rosenstock TR, Bertoncini CRA, Teles AV, Hirata H, Fernandes MJS, Smaili SS. Glutamate-induced alterations in Ca2+ signaling are modulated by mitochondrial Ca2+ handling capacity in brain slices of R6/1 transgenic mice. Eur J Neurosci 2011; 32:60-70. [PMID: 20608968 DOI: 10.1111/j.1460-9568.2010.07268.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Huntington's disease is a neurodegenerative disorder caused by an expansion of CAGs repeats and characterized by alterations in mitochondrial functions. Although changes in Ca(2+) handling have been suggested, the mechanisms involved are not completely understood. The aim of this study was to investigate the possible alterations in Ca(2+) handling capacity and the relationship with mitochondrial dysfunction evaluated by NAD(P)H fluorescence, reactive oxygen species levels, mitochondrial membrane potential (DeltaPsi(m)) measurements and respiration in whole brain slices from R6/1 mice of different ages, evaluated in situ by real-time real-space microscopy. We show that the cortex and striatum of the 9-month-old R6/1 transgenic mice present a significant sustained increase in cytosolic Ca(2+) induced by glutamate (Glu). This difference in Glu response was partially reduced in R6/1 when in the absence of extracellular Ca(2+), indicating that N-methyl-D-aspartate receptors participation in this response is more important in transgenic mice. In addition, Glu also lead to a decrease in NAD(P)H fluorescence, a loss in DeltaPsi(m) and a further increase in respiration, which may have evoked a decrease in mitochondrial Ca(2+) Ca(2+)(m) uptake capacity. Taken together, these results show that alterations in Ca(2+) homeostasis in transgenic mice are associated with a decrease in Ca(2+)(m) uptake mechanism with a diminished Ca(2+) handling ability that ultimately causes dysfunctions and worsening of the neurodegenerative and the disease processes.
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Affiliation(s)
- T R Rosenstock
- Departamento de Farmacologia, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, SP, Brazil
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14
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Abstract
The ability of mitochondria to sequester and retain divalent cations in the form of precipitates consisting of organic and inorganic moieties has been known for decades. Of these cations, Ca(2+) has emerged as a major player in both signal transduction and cell death mechanisms, and, as a consequence, the importance of mitochondria in these processes was soon recognized. Early studies showed considerable effort in identifying the mechanisms of Ca(2+) sequestration, precipitation and release by uncouplers of oxidative phosphorylation; however, relatively little information was obtained, and these processes were eventually taken for granted. Here, we re-examine: (a) the thermodynamic aspects of mitochondrial Ca(2+) uptake and release, (b) the insufficiently explained effect of uncouplers in inducing mitochondrial Ca(2+) release, (c) the thermodynamic effects of exogenously added adenine nucleotides on mitochondrial Ca(2+) uptake capacity and precipitate formation, and (d) the elusive nature of the Ca(2+) -phosphate precipitates formed in the mitochondrial matrix.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group, Hungarian Academy of Sciences, Budapest, Hungary.
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15
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Toxicological and pathophysiological roles of reactive oxygen and nitrogen species. Toxicology 2010; 276:85-94. [PMID: 20643181 DOI: 10.1016/j.tox.2010.07.009] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/23/2010] [Accepted: 07/11/2010] [Indexed: 01/20/2023]
Abstract
'Oxidative and Nitrative Stress in Toxicology and Disease' was the subject of a symposium held at the EUROTOX meeting in Dresden 15th September 2009. Reactive oxygen (ROS) and reactive nitrogen species (RNS) produced during tissue pathogenesis and in response to viral or chemical toxicants, induce a complex series of downstream adaptive and reparative events driven by the associated oxidative and nitrative stress. As highlighted by all the speakers, ROS and RNS can promote diverse biological responses associated with a spectrum of disorders including neurodegenerative/neuropsychiatric and cardiovascular diseases. Similar pathways are implicated during the process of liver and skin carcinogenesis. Mechanistically, reactive oxygen and nitrogen species drive sustained cell proliferation, cell death including both apoptosis and necrosis, formation of nuclear and mitochondrial DNA mutations, and in some cases stimulation of a pro-angiogenic environment. Here we illustrate the pivotal role played by oxidative and nitrative stress in cell death, inflammation and pain and its consequences for toxicology and disease pathogenesis. Examples are presented from five different perspectives ranging from in vitro model systems through to in vivo animal model systems and clinical outcomes.
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Abstract
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system playing critical roles in basal synaptic transmission and mechanisms of learning and memory. Under normal conditions, glutamate is sequestered within synaptic vesicles (approximately 100 mM) with extracellular glutamate concentrations being limited (<1 microM), via retrieval by plasma-membrane transporters on neuronal and glial cells. In the case of central nervous system trauma, stroke, epilepsy, and in certain neurodegenerative diseases, increased concentrations of extracellular glutamate (by vesicular release, cell lysis and/or decreased glutamate transporter uptake/reversal) stimulate the overactivation of local ionotropic glutamate receptors that trigger neuronal cell death (excitotoxicity). Other natural agonists, such as domoic acid, alcohol and auto-antibodies, have also been reported to induce excitotoxicity.
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17
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Smith AJ, Tauskela JS, Stone TW, Smith RA. Preconditioning with 4-aminopyridine protects cerebellar granule neurons against excitotoxicity. Brain Res 2009; 1294:165-75. [DOI: 10.1016/j.brainres.2009.07.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 07/16/2009] [Accepted: 07/18/2009] [Indexed: 01/23/2023]
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18
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Abstract
AbstractMitochondrial enzyme monoamine oxidase A (MAO-A) generates hydrogen peroxide (H2O2) and is up-regulated by Ca2+ and presumably by ammonia. We hypothesized that MAO-A may be under the control of NMDA receptors in hyperammonemia. In this work, the in vivo effects of single dosing with ammonia and NMDA receptor antagonist MK-801 and the in vitro effect of Ca2+ on MAO-A activity in isolated rat brain mitochondria were studied employing enzymatic procedure. Intraperitoneal injection of rats with ammonia led to an increase in MAO-A activity in mitochondria indicating excessive H2O2 generation. Calcium added to isolated mitochondria stimulated MAO-A activity by as much as 84%. MK-801 prevented the in vivo effect of ammonia, implying that MAO-A activation in hyperammonemia is mediated by NMDA receptors. These data support the conclusion that brain mitochondrial MAO-A is regulated by the function of NMDA receptors. The enzyme can contribute to the oxidative stress associated with hyperammonemic conditions such as encephalopathy and Alzheimer’s disease. The attenuation of the oxidative stress highlights MAO-A inactivation and NMDA receptor antagonists as sources of novel avenues in the treatment of mental disorders.
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Calcium alters monoamine oxidase-A parameters in human cerebellar and rat glial C6 cell extracts: possible influence by distinct signalling pathways. Life Sci 2009; 85:262-8. [PMID: 19539632 DOI: 10.1016/j.lfs.2009.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 05/15/2009] [Accepted: 06/09/2009] [Indexed: 01/24/2023]
Abstract
AIMS Calcium (Ca(2+)) is known to augment monoamine oxidase-A (MAO-A) activity in cell cultures as well as in brain extracts from several species. This association between Ca(2+) and MAO-A could contribute to their respective roles in cytotoxicity. However, the effect of Ca(2+) on MAO-A function in human brain has as yet to be examined as does the contribution of specific signalling cascades. MAIN METHODS We examined the effects of Ca(2+) on MAO-A activity and on [(3)H]Ro 41-1049 binding to MAO-A in human cerebellar extracts, and compared this to its effects on MAO-A activity in glial C6 cells following the targeting of signalling pathways using specific chemical inhibitors. KEY FINDINGS Ca(2+) enhances MAO-A activity as well as the association of [(3)H]Ro 41-1049 to MAO-A in human cerebellar extracts. The screening of neuronal and glial cell cultures reveals that MAO-A activity does not always correlate with the expression of either mao-A mRNA or MAO-A protein. Inhibition of the individual PI3K/Akt, ERK and p38(MAPK) signalling pathways in glial C6 cells all augment basal MAO-A activity. Inhibition of the p38(MAPK) pathway also augments Ca(2+)-sensitive MAO-A activity. We also observe the inverse relation between p38(MAPK) activation and MAO-A function in C6 cultures grown to full confluence. SIGNIFICANCE The Ca(2+)-sensitive component to MAO-A activity is present in human brain and in vitro studies link it to the p38(MAPK) pathway. This means of influencing MAO-A function could explain its role in pathologies as diverse as neurodegeneration and cancers.
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Vajda S, Mándi M, Konràd C, Kiss G, Ambrus A, Adam-Vizi V, Chinopoulos C. A re-evaluation of the role of matrix acidification in uncoupler-induced Ca2+release from mitochondria. FEBS J 2009; 276:2713-24. [DOI: 10.1111/j.1742-4658.2009.06995.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Regulation of glucose transporter 3 surface expression by the AMP-activated protein kinase mediates tolerance to glutamate excitation in neurons. J Neurosci 2009; 29:2997-3008. [PMID: 19261894 DOI: 10.1523/jneurosci.0354-09.2009] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Ischemic and excitotoxic events within the brain result in rapid and often unfavorable depletions in neuronal energy levels. Here, we investigated the signaling pathways activated in response to the energetic stress created by transient glutamate excitation in cerebellar granule neurons. We characterized a glucose dependent hyperpolarization of the mitochondrial membrane potential (Delta psi(m)) in the majority of neurons after transient glutamate excitation. Expression levels of the primary neuronal glucose transporters (GLUTs) isoforms 1, 3, 4, and 8 were found to be unaltered within a 24 h period after excitation. However, a significant increase only in GLUT3 surface expression was identified 30 min after excitation, with this high surface expression remaining significantly above control levels in many neurons for up to 4 h. Glutamate excitation induced a rapid alteration in the AMP:ATP ratio that was associated with the activation of the AMP-activated protein kinase (AMPK). Interestingly, pharmacological activation of AMPK with AICAR (5-aminoimidazole-4-carboxamide riboside) alone also increased GLUT3 surface expression, with a hyperpolarization of Delta psi(m) evident in many neurons. Notably, inhibition of the CaMKK (calmodulin-dependent protein kinase kinase) had little affect on GLUT translocation, whereas the inhibition or knockdown of AMPK (compound C, siRNA) activity prevented GLUT3 translocation to the cell surface after glutamate excitation. Furthermore, gene silencing of GLUT3 eradicated the increase in Delta psi(m) associated with transient glutamate excitation and potently sensitized neurons to excitotoxicity. In summary, our data suggest that the activation of AMPK and its regulation of cell surface GLUT3 expression is critical in mediating neuronal tolerance to excitotoxicity.
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Huang F, Dong X, Zhang L, Zhang X, Zhao D, Bai X, Li Z. The neuroprotective effects of NGF combined with GM1 on injured spinal cord neurons in vitro. Brain Res Bull 2009; 79:85-8. [PMID: 19133317 DOI: 10.1016/j.brainresbull.2008.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 12/03/2008] [Accepted: 12/05/2008] [Indexed: 11/29/2022]
Abstract
Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for neuronal survival, differentiation and maturation. The aim of the present study was to investigate whether co-administration of GM1 and NGF reverses glutamate (Glu) neurotoxicity in primary cultured rat embryonic spinal cord neurons. Spinal cord neurons were exposed to Glu (2 mmol/l), Glu (2 mmol/l) plus GM1 (10 mg/ml), Glu (2 mmol/l) plus NGF (10 ng/ml), Glu (2 mmol/l) plus GM1 (5 mg/ml) and NGF (5 ng/ml) and then processed for detecting intracellular concentrations of Ca2+([Ca2+]i) by confocal laser scanning microscopy and growth associated protein 43 (GAP43) mRNA by RT-PCR. The fluorescent intensity in Glu plus GM1 and NGF incubated neurons was the lowest as compared with that in other groups. The expression of GAP43 mRNA in Glu plus GM1 and NGF incubated neurons was the highest as compared with that in other groups. These results implicated that GM1 and NGF have synergistic neuroprotective effects on spinal cord neurons with excitotoxicity induced by Glu in vitro.
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Affiliation(s)
- Fei Huang
- Department of Human Anatomy, Binzhou Medical College, No. 346 Guanhai Road, Yantai 264003, China
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23
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Specific targeting of pro-death NMDA receptor signals with differing reliance on the NR2B PDZ ligand. J Neurosci 2008; 28:10696-710. [PMID: 18923045 DOI: 10.1523/jneurosci.1207-08.2008] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NMDA receptors (NMDARs) mediate ischemic brain damage, for which interactions between the C termini of NR2 subunits and PDZ domain proteins within the NMDAR signaling complex (NSC) are emerging therapeutic targets. However, expression of NMDARs in a non-neuronal context, lacking many NSC components, can still induce cell death. Moreover, it is unclear whether targeting the NSC will impair NMDAR-dependent prosurvival and plasticity signaling. We show that the NMDAR can promote death signaling independently of the NR2 PDZ ligand, when expressed in non-neuronal cells lacking PSD-95 and neuronal nitric oxide synthase (nNOS), key PDZ proteins that mediate neuronal NMDAR excitotoxicity. However, in a non-neuronal context, the NMDAR promotes cell death solely via c-Jun N-terminal protein kinase (JNK), whereas NMDAR-dependent cortical neuronal death is promoted by both JNK and p38. NMDAR-dependent pro-death signaling via p38 relies on neuronal context, although death signaling by JNK, triggered by mitochondrial reactive oxygen species production, does not. NMDAR-dependent p38 activation in neurons is triggered by submembranous Ca(2+), and is disrupted by NOS inhibitors and also a peptide mimicking the NR2B PDZ ligand (TAT-NR2B9c). TAT-NR2B9c reduced excitotoxic neuronal death and p38-mediated ischemic damage, without impairing an NMDAR-dependent plasticity model or prosurvival signaling to CREB or Akt. TAT-NR2B9c did not inhibit JNK activation, and synergized with JNK inhibitors to ameliorate severe excitotoxic neuronal loss in vitro and ischemic cortical damage in vivo. Thus, NMDAR-activated signals comprise pro-death pathways with differing requirements for PDZ protein interactions. These signals are amenable to selective inhibition, while sparing synaptic plasticity and prosurvival signaling.
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Concannon CG, Ward MW, Bonner HP, Kuroki K, Tuffy LP, Bonner CT, Woods I, Engel T, Henshall DC, Prehn JHM. NMDA receptor-mediated excitotoxic neuronal apoptosis in vitro and in vivo occurs in an ER stress and PUMA independent manner. J Neurochem 2008; 105:891-903. [PMID: 18088354 DOI: 10.1111/j.1471-4159.2007.05187.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Disruption of endoplasmic reticulum (ER) Ca2+ homeostasis and ER dysfunction have been suggested to contribute to excitotoxic and ischaemic neuronal injury. Previously, we have characterized the neural transcriptome following ER stress and identified the BH3-only protein, p53 up-regulated mediator of apoptosis (PUMA), as a central mediator of ER stress toxicity. In this study, we investigated the effects of excitotoxic injury on ER Ca2+ levels and induction of ER stress responses in models of glutamate- and NMDA-induced excitotoxic apoptosis. While exposure to the ER stressor tunicamycin induced an ER stress response in cerebellar granule neurons, transcriptional activation of targets of the ER stress response, including PUMA, were absent following glutamate-induced apoptosis. Confocal imaging revealed no long-term changes in the ER Ca2+ level in response to glutamate. Murine cortical neurons and organotypic hippocampal slice cultures from PUMA+/+ and PUMA-/- animals provided no evidence of ER stress and did not differ in their sensitivity to NMDA. Finally, NMDA-induced excitotoxic apoptosis in vivo was not associated with ER stress, nor did deficiency in PUMA alleviate the injury induced. Our data suggest that NMDA receptor-mediated excitotoxic apoptosis occurs in vitro and in vivo in an ER stress and PUMA independent manner.
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Affiliation(s)
- Caoimhín G Concannon
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
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25
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Huang F, Liu Z, Liu H, Wang L, Wang H, Li Z. GM1 and NGF modulate Ca2+ homeostasis and GAP43 mRNA expression in cultured dorsal root ganglion neurons with excitotoxicity induced by glutamate. Nutr Neurosci 2008; 10:105-11. [PMID: 18019391 DOI: 10.1080/10284150701406752] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Monosialoganglioside (GM1) has been considered to have a neurotrophic factor-like activity. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for neuronal survival, differentiation and maturation. The aim of the present study was to investigate whether co-administration of GM1 and NGF reverses glutamate (Glu) neurotoxicity in primary cultured rat embryonic dorsal root ganglion (DRG) neurons. DRG neurons were exposed to Glu (2 mmol/1), Glu (2 mmol/1) plus GM1 (10 microg/ml), Glu (2 mmol/l) plus NGF (10 ng/ml), Glu (2 mmol/l) plus GM1 (5 microg/ml) and NGF (5 ng/ml) and then processed for detecting intracellular concentrations of Ca2+ ([Ca2+] i) by confocal laser scanning microscopy and growth-associated protein 43 (GAP43) mRNA by RT-PCR. The fluorescent intensity in Glu plus GM1 and NGF incubated neurons was the lowest as compared with that in other groups. The expression of GAP43 mRNA in Glu plus GM1 and NGF incubated neurons was the highest as compared with that in other groups. These results implicated that GM1 and NGF have synergistic neuroprotective effects on DRG neurons with excitotoxicity induced by Glu in vitro.
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Affiliation(s)
- Fei Huang
- Department of Anatomy, Shandong University School of Medicine, Jinan 250012, People's Republic of China
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26
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Dendritic and mitochondrial changes during glutamate excitotoxicity. Neuropharmacology 2007; 53:891-8. [DOI: 10.1016/j.neuropharm.2007.10.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 09/11/2007] [Accepted: 10/01/2007] [Indexed: 11/18/2022]
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27
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Kristian T, Pivovarova NB, Fiskum G, Andrews SB. Calcium-induced precipitate formation in brain mitochondria: composition, calcium capacity, and retention. J Neurochem 2007; 102:1346-56. [PMID: 17663756 PMCID: PMC2566803 DOI: 10.1111/j.1471-4159.2007.04626.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Both isolated brain mitochondria and mitochondria in intact neurons are capable of accumulating large amounts of calcium, which leads to formation in the matrix of calcium- and phosphorus-rich precipitates, the chemical composition of which is largely unknown. Here, we have used inhibitors of the mitochondrial permeability transition (MPT) to determine how the amount and rate of mitochondrial calcium uptake relate to mitochondrial morphology, precipitate composition, and precipitate retention. Using isolated rat brain (RBM) or liver mitochondria (RLM) Ca(2+)-loaded by continuous cation infusion, precipitate composition was measured in situ in parallel with Ca(2+) uptake and mitochondrial swelling. In RBM, the endogenous MPT inhibitors adenosine 5'-diphosphate (ADP) and adenosine 5'-triphosphate (ATP) increased mitochondrial Ca(2+) loading capacity and facilitated formation of precipitates. In the presence of ADP, the Ca/P ratio approached 1.5, while ATP or reduced infusion rates decreased this ratio towards 1.0, indicating that precipitate chemical form varies with the conditions of loading. In both RBM and RLM, the presence of cyclosporine A in addition to ADP increased the Ca(2+) capacity and precipitate Ca/P ratio. Following MPT and/or depolarization, the release of accumulated Ca(2+) is rapid but incomplete; significant residual calcium in the form of precipitates is retained in damaged mitochondria for prolonged periods.
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Affiliation(s)
- Tibor Kristian
- Department of Anesthesiology, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA.
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28
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Cao X, Wei Z, Gabriel GG, Li X, Mousseau DD. Calcium-sensitive regulation of monoamine oxidase-A contributes to the production of peroxyradicals in hippocampal cultures: implications for Alzheimer disease-related pathology. BMC Neurosci 2007; 8:73. [PMID: 17868476 PMCID: PMC2048967 DOI: 10.1186/1471-2202-8-73] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2007] [Accepted: 09/16/2007] [Indexed: 01/20/2023] Open
Abstract
Background Calcium (Ca2+) has recently been shown to selectively increase the activity of monoamine oxidase-A (MAO-A), a mitochondria-bound enzyme that generates peroxyradicals as a natural by-product of the deamination of neurotransmitters such as serotonin. It has also been suggested that increased intracellular free Ca2+ levels as well as MAO-A may be contributing to the oxidative stress associated with Alzheimer disease (AD). Results Incubation with Ca2+ selectively increases MAO-A enzymatic activity in protein extracts from mouse hippocampal HT-22 cell cultures. Treatment of HT-22 cultures with the Ca2+ ionophore A23187 also increases MAO-A activity, whereas overexpression of calbindin-D28K (CB-28K), a Ca2+-binding protein in brain that is greatly reduced in AD, decreases MAO-A activity. The effects of A23187 and CB-28K are both independent of any change in MAO-A protein or gene expression. The toxicity (via production of peroxyradicals and/or chromatin condensation) associated with either A23187 or the AD-related β-amyloid peptide, which also increases free intracellular Ca2+, is attenuated by MAO-A inhibition in HT-22 cells as well as in primary hippocampal cultures. Conclusion These data suggest that increases in intracellular Ca2+ availability could contribute to a MAO-A-mediated mechanism with a role in AD-related oxidative stress.
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Affiliation(s)
- Xia Cao
- The Cell Signalling Laboratory, Neuropsychiatry Research Unit, University of Saskatchewan, 103 Wiggins Road, Saskatoon, SK S7N 5E4, Canada
| | - Zelan Wei
- The Cell Signalling Laboratory, Neuropsychiatry Research Unit, University of Saskatchewan, 103 Wiggins Road, Saskatoon, SK S7N 5E4, Canada
| | - Geraldine G Gabriel
- The Cell Signalling Laboratory, Neuropsychiatry Research Unit, University of Saskatchewan, 103 Wiggins Road, Saskatoon, SK S7N 5E4, Canada
| | - XinMin Li
- The Cell Signalling Laboratory, Neuropsychiatry Research Unit, University of Saskatchewan, 103 Wiggins Road, Saskatoon, SK S7N 5E4, Canada
| | - Darrell D Mousseau
- The Cell Signalling Laboratory, Neuropsychiatry Research Unit, University of Saskatchewan, 103 Wiggins Road, Saskatoon, SK S7N 5E4, Canada
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29
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Ward MW, Huber HJ, Weisová P, Düssmann H, Nicholls DG, Prehn JHM. Mitochondrial and plasma membrane potential of cultured cerebellar neurons during glutamate-induced necrosis, apoptosis, and tolerance. J Neurosci 2007; 27:8238-49. [PMID: 17670970 PMCID: PMC6673046 DOI: 10.1523/jneurosci.1984-07.2007] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A failure of mitochondrial bioenergetics has been shown to be closely associated with the onset of apoptotic and necrotic neuronal injury. Here, we developed an automated computational model that interprets the single-cell fluorescence for tetramethylrhodamine methyl ester (TMRM) as a consequence of changes in either delta psi(m) or delta psi(p), thus allowing for the characterization of responses for populations of single cells and subsequent statistical analysis. Necrotic injury triggered by prolonged glutamate excitation resulted in a rapid monophasic or biphasic loss of delta psi(m) that was closely associated with a loss of delta psi(p) and a rapid decrease in neuronal NADPH and ATP levels. Delayed apoptotic injury, induced by transient glutamate excitation, resulted in a small, reversible decrease in TMRM fluorescence, followed by a sustained hyperpolarization of delta psi(m) as confirmed using the delta psi(p)-sensitive anionic probe DiBAC2(3). This hyperpolarization of delta psi(m) was closely associated with a significant increase in neuronal glucose uptake, NADPH availability, and ATP levels. Statistical analysis of the changes in delta psi(m) or delta psi(p) at a single-cell level revealed two major correlations; those neurons displaying a more pronounced depolarization of delta psi(p) during the initial phase of glutamate excitation entered apoptosis more rapidly, and neurons that displayed a more pronounced hyperpolarization of delta psi(m) after glutamate excitation survived longer. Indeed, those neurons that were tolerant to transient glutamate excitation (18%) showed the most significant increases in delta psi(m). Our results indicate that a hyperpolarization of delta psi(m) is associated with increased glucose uptake, NADPH availability, and survival responses during excitotoxic injury.
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Affiliation(s)
- Manus W. Ward
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Heinrich J. Huber
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- Siemens Medical Division, Siemens Ireland, Dublin 2, Ireland, and
| | - Petronela Weisová
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Heiko Düssmann
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - David G. Nicholls
- Buck Institute for Age Research, Mitochondrial Physiology, Novato, California 94945
| | - Jochen H. M. Prehn
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, Dublin 2, Ireland
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30
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Greenwood SM, Mizielinska SM, Frenguelli BG, Harvey J, Connolly CN. Mitochondrial dysfunction and dendritic beading during neuronal toxicity. J Biol Chem 2007; 282:26235-44. [PMID: 17616519 DOI: 10.1074/jbc.m704488200] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial dysfunction (depolarization and structural collapse), cytosolic ATP depletion, and neuritic beading are early hallmarks of neuronal toxicity induced in a variety of pathological conditions. We show that, following global exposure to glutamate, mitochondrial changes are spatially and temporally coincident with dendritic bead formation. During oxygen-glucose deprivation, mitochondrial depolarization precedes mitochondrial collapse, which in turn is followed by dendritic beading. These events travel as a wave of activity from distal dendrites toward the neuronal cell body. Despite the spatiotemporal relationship between dysfunctional mitochondria and dendritic beads, mitochondrial depolarization and cytoplasmic ATP depletion do not trigger these events. However, mitochondrial dysfunction increases neuronal vulnerability to these morphological changes during normal physiological activity. Our findings support a mechanism whereby, during glutamate excitotoxicity, Ca(2+) influx leads to mitochondrial depolarization, whereas Na(+) influx leads to an unsustainable increase in ATP demand (Na(+),K(+)-ATPase activity). This leads to a drop in ATP levels, an accumulation of intracellular Na(+) ions, and the subsequent influx of water, leading to microtubule depolymerization, mitochondrial collapse, and dendritic beading. Following the removal of a glutamate challenge, dendritic recovery is dependent upon the integrity of the mitochondrial membrane potential, but not on a resumption of ATP synthesis or Na(+),K(+)-ATPase activity. Thus, dendritic recovery is not a passive reversal of the events that induce dendritic beading. These findings suggest that the degree of calcium influx and mitochondrial depolarization inflicted by a neurotoxic challenge, determines the ability of the neuron to recover its normal morphology.
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Affiliation(s)
- Sam M Greenwood
- Neurosciences Institute, Ninewells Medical School, University of Dundee, Dundee DD19SY, Scotland, United Kingdom
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31
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Jacquard C, Trioulier Y, Cosker F, Escartin C, Bizat N, Hantraye P, Cancela JM, Bonvento G, Brouillet E. Brain mitochondrial defects amplify intracellular [Ca2+] rise and neurodegeneration but not Ca2+entry during NMDA receptor activation. FASEB J 2006; 20:1021-3. [PMID: 16571773 DOI: 10.1096/fj.05-5085fje] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
According to the "indirect" excitotoxicity hypothesis, mitochondrial defects increase Ca2+ entry into neurons by rendering NMDA-R hypersensitive to glutamate. We tested this hypothesis by investigating in the rat striatum and cultured striatal cells how partial mitochondrial complex II inhibition produced by 3-nitropropionic acid (3NP) modifies the toxicity of the NMDA-R agonist quinolinate (QA). We showed that nontoxic 3NP treatment, leading to partial inhibition of complex II activity, greatly exacerbated striatal degeneration produced by slightly toxic QA treatment through an "all-or-nothing" process. The potentiation of QA-induced cell death by 3NP was associated with increased calpain activity and massive calpain-mediated cleavage of several postsynaptic proteins, suggesting major neuronal Ca2+ deregulation in the striatum. However, Ca2+ anomalies probably do not result from NMDA-R hypersensitivity. Indeed, brain imaging experiments using [(18)F]fluorodeoxyglucose indirectly showed that 3NP did not increase QA-induced ionic perturbations at the striatal glutamatergic synapses in vivo. Consistent with this, the exacerbation of QA toxicity by 3NP was not related to an increase in the QA-induced entry of 45Ca2+ into striatal neurons. The present results demonstrate that the potentiation of NMDA-R-mediated excitotoxicity by mitochondrial defects involves primarily intracellular Ca2+ deregulation, in the absence of NMDA-R hypersensitivity.
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Affiliation(s)
- Carine Jacquard
- Unité de Recherche Associée CEA-CNRS 2210, Service Hospitalier Frédéric Joliot, Département de Recherches Médicales, Direction des Sciences du Vivant, Commissariat à l'Energie Atomique, 4 place du Général Leclerc, 91401 Orsay cedex, France
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32
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Kitamura Y, Iida Y, Abe J, Ueda M, Mifune M, Kasuya F, Ohta M, Igarashi K, Saito Y, Saji H. Protective effect of zinc against ischemic neuronal injury in a middle cerebral artery occlusion model. J Pharmacol Sci 2006; 100:142-8. [PMID: 16474205 DOI: 10.1254/jphs.fp0050805] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
In this study, we investigated the effect of vesicular zinc on ischemic neuronal injury. In cultured neurons, addition of a low concentration (under 100 microM) of zinc inhibited both glutamate-induced calcium influx and neuronal death. In contrast, a higher concentration (over 150 microM) of zinc decreased neuronal viability, although calcium influx was inhibited. These results indicate that zinc exhibits biphasic effects depending on its concentration. Furthermore, in cultured neurons, co-addition of glutamate and CaEDTA, which binds extra-cellular zinc, increased glutamate-induced calcium influx and aggravated the neurotoxicity of glutamate. In a rat transient middle cerebral artery occlusion (MCAO) model, the infarction volume, which is related to the neurotoxicity of glutamate, increased rapidly on the intracerebral ventricular injection of CaEDTA 30 min prior to occlusion. These results suggest that zinc released from synaptic vesicles may provide a protective effect against ischemic neuronal injury.
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Affiliation(s)
- Youji Kitamura
- Graduate School of Medicine and Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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33
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Ward MW, Rehm M, Duessmann H, Kacmar S, Concannon CG, Prehn JHM. Real time single cell analysis of Bid cleavage and Bid translocation during caspase-dependent and neuronal caspase-independent apoptosis. J Biol Chem 2005; 281:5837-44. [PMID: 16407197 DOI: 10.1074/jbc.m511562200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bcl-2 homology domain (BH) 3-only proteins couple stress signals to evolutionarily conserved mitochondrial apoptotic pathways. Caspase 8-mediated cleavage of the BH3-only protein Bid into a truncated protein (tBid) and subsequent translocation of tBid to mitochondria has been implicated in death receptor signaling. We utilized a recombinant fluorescence resonance energy transfer (FRET) Bid probe to determine the kinetics of Bid cleavage and tBid translocation during death receptor-induced apoptosis in caspase 3-deficient MCF-7 cells. Cells treated with tumor necrosis factor-alpha (200 ng/ml) showed a rapid cleavage of the Bid-FRET probe occurring 75.4 +/- 12.6 min after onset of the tumor necrosis factor-alpha exposure. Cleavage of the Bid-FRET probe coincided with a translocation of tBid to the mitochondria and a collapse of the mitochondrial membrane potential (DeltaPsim). We next investigated the role of Bid cleavage in a model of caspase-independent, glutamate-induced excitotoxic apoptosis. Rat cerebellar granule neurons were transfected with the Bid-FRET probe and exposed to glutamate for 5 min. In contrast to death receptor-induced apoptosis, neurons showed a translocation of full-length Bid to the mitochondria. This translocation occurred 5.6 +/- 1.7 h after the termination of the glutamate exposure and was also paralleled with a collapse of the DeltaPsim. Proteolytic cleavage of the FRET probe also occurred, however, only 25.2 +/- 3.5 min after its translocation to the mitochondria. Subfractionation experiments confirmed a translocation of full-length Bid from the cytosolic to the mitochondrial fraction during excitotoxic apoptosis. Our data demonstrate that both tBid and full-length Bid have the capacity to translocate to mitochondria during apoptosis.
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Affiliation(s)
- Manus W Ward
- Department of Physiology and Medical Physics and RCSI Neuroscience Research Centre, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
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34
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Brown JM, Quinton MS, Yamamoto BK. Methamphetamine-induced inhibition of mitochondrial complex II: roles of glutamate and peroxynitrite. J Neurochem 2005; 95:429-36. [PMID: 16086684 DOI: 10.1111/j.1471-4159.2005.03379.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-dose methamphetamine (METH) is associated with long-term deficits in dopaminergic systems. Although the mechanism(s) which contributes to these deficits is not known, glutamate and peroxynitrite are likely to play a role. These factors are hypothesized to inhibit mitochondrial function, increasing the free radical burden and decreasing neuronal energy supplies. Previous studies suggest a role for the mitochondrial electron transport chain (ETC) in mediating toxicity of METH. The purpose of the present studies was to determine whether METH administration selectively inhibits complex II of the ETC in rats. High-dose METH administration (10 mg/kg every 2 h x 4) rapidly (within 1 h) decreased complex II (succinate dehydrogenase) activity by approximately 20-30%. In addition, decreased activity of complex II-III, but not complex I-III, of the mitochondrial ETC was also observed 24 h after METH. This inhibition was not due to direct inhibition by METH or METH-induced hyperthermia and was specific to striatal brain regions. METH-induced decreases in complex II-III were prevented by MK-801 and the peroxynitrite scavenger 5,10,15,20-tetrakis (2,4,6-trimethyl-3,5-sulphonatophenyl) porphinato iron III. These findings provide the first evidence that METH administration, via glutamate receptor activation and peroxynitrite formation, selectively alters a specific site of the ETC.
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Affiliation(s)
- Jeffrey M Brown
- Department of Pharmacology and Experimental Therapeutics, Laboratory of Neurochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Kushnareva YE, Wiley SE, Ward MW, Andreyev AY, Murphy AN. Excitotoxic injury to mitochondria isolated from cultured neurons. J Biol Chem 2005; 280:28894-902. [PMID: 15932874 DOI: 10.1074/jbc.m503090200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuronal death in response to excitotoxic levels of glutamate is dependent upon mitochondrial Ca2+ accumulation and is associated with a drop in ATP levels and a loss in ionic homeostasis. Yet the mapping of temporal events in mitochondria subsequent to Ca2+ sequestration is incomplete. By isolating mitochondria from primary cultures, we discovered that glutamate treatment of cortical neurons for 10 min caused 44% inhibition of ADP-stimulated respiration, whereas the maximal rate of electron transport (uncoupler-stimulated respiration) was inhibited by approximately 10%. The Ca2+ load in mitochondria from glutamate-treated neurons was estimated to be 167 +/- 19 nmol/mg protein. The glutamate-induced Ca2+ load was less than the maximal Ca2+ uptake capacity of the mitochondria determined in vitro (363 +/- 35 nmol/mg protein). Comparatively, mitochondria isolated from cerebellar granule cells demonstrated a higher Ca2+ uptake capacity (686 +/- 71 nmol/mg protein) than the cortical mitochondria, and the glutamate-induced load of Ca2+ was a smaller percentage of the maximal Ca2+ uptake capacity. Thus, this study indicated that Ca(2+)-induced impairment of mitochondrial ATP production is an early event in the excitotoxic cascade that may contribute to decreased cellular ATP and loss of ionic homeostasis that precede commitment to neuronal death.
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