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Ahad MA, Kumaran KR, Ning T, Mansor NI, Effendy MA, Damodaran T, Lingam K, Wahab HA, Nordin N, Liao P, Müller CP, Hassan Z. Insights into the neuropathology of cerebral ischemia and its mechanisms. Rev Neurosci 2020; 31:521-538. [DOI: 10.1515/revneuro-2019-0099] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/09/2020] [Indexed: 11/15/2022]
Abstract
AbstractCerebral ischemia is a result of insufficient blood flow to the brain. It leads to limited supply of oxygen and other nutrients to meet metabolic demands. These phenomena lead to brain damage. There are two types of cerebral ischemia: focal and global ischemia. This condition has significant impact on patient’s health and health care system requirements. Animal models such as transient occlusion of the middle cerebral artery and permanent occlusion of extracranial vessels have been established to mimic the conditions of the respective type of cerebral ischemia and to further understand pathophysiological mechanisms of these ischemic conditions. It is important to understand the pathophysiology of cerebral ischemia in order to identify therapeutic strategies for prevention and treatment. Here, we review the neuropathologies that are caused by cerebral ischemia and discuss the mechanisms that occur in cerebral ischemia such as reduction of cerebral blood flow, hippocampal damage, white matter lesions, neuronal cell death, cholinergic dysfunction, excitotoxicity, calcium overload, cytotoxic oedema, a decline in adenosine triphosphate (ATP), malfunctioning of Na+/K+-ATPase, and the blood-brain barrier breakdown. Altogether, the information provided can be used to guide therapeutic strategies for cerebral ischemia.
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Affiliation(s)
- Mohamad Anuar Ahad
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Kesevan Rajah Kumaran
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Tiang Ning
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Nur Izzati Mansor
- Medical Genetics Unit, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
- Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | | | - Thenmoly Damodaran
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Kamilla Lingam
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Habibah Abdul Wahab
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia
- USM-RIKEN Centre for Aging Science (URICAS), Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
| | - Norshariza Nordin
- Medical Genetics Unit, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
- Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Ping Liao
- Calcium Signaling Laboratory, National Neuroscience Institute, Singapore 308433, Singapore
| | - Christian P. Müller
- Section of Addiction Medicine, Department of Psychiatry and Psychotherapy, University Clinic, Friedrich Alexander University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Zurina Hassan
- Centre for Drug Research, Universiti Sains Malaysia, 11800 Penang, Malaysia
- USM-RIKEN Centre for Aging Science (URICAS), Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
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2
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Karunasinghe RN, Grey AC, Telang R, Vlajkovic SM, Lipski J. Differential spread of anoxic depolarization contributes to the pattern of neuronal injury after oxygen and glucose deprivation (OGD) in the Substantia Nigra in rat brain slices. Neuroscience 2016; 340:359-372. [PMID: 27826106 DOI: 10.1016/j.neuroscience.2016.10.067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/14/2016] [Accepted: 10/29/2016] [Indexed: 12/21/2022]
Abstract
Anoxic depolarization (AD) is an acute event evoked by brain ischemia, involving a profound loss of cell membrane potential and swelling that spreads over susceptible parts of the gray matter. Its occurrence is a strong predictor of the severity of neuronal injury. Little is known about this event in the Substantia Nigra, a midbrain nucleus critical for motor control. We tested the effects of oxygen and glucose deprivation (OGD), an in vitro model of brain ischemia, in rat midbrain slices. AD developed within 4min from OGD onset and spread in the Substantia Nigra pars reticulata (SNr), but not through the Substantia Nigra pars compacta (SNc). This differential effect involved a contrasting pattern of changes in membrane potential between dopamine-producing SNc and non-dopaminergic SNr neurons. A fast depolarization in SNr neurons was not followed by repolarization after the end of OGD, and was associated with swollen somata and beaded dendrites. In contrast, slowly developing depolarization of SNc neurons led to repolarization after OGD ended, and no changes in neuronal morphology were observed. The AD-resistance of the SNc involved smaller dysregulations of K+ and Ca2+ ions, and a slower loss of energy metabolites. Our results show that acute ischemia profoundly impairs the function and morphology of SNr neurons but not adjacent SNc neurons, and that the surprising higher tolerance of SNc neurons correlates with the resistance of the SNc region to AD. This differential response may affect the pattern of early neuronal injury that develops in the brainstem after acute ischemic insults.
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Affiliation(s)
- Rashika N Karunasinghe
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Angus C Grey
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Ravindra Telang
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Srdjan M Vlajkovic
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Janusz Lipski
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand.
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3
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Roome CJ, Power EM, Empson RM. Transient reversal of the sodium/calcium exchanger boosts presynaptic calcium and synaptic transmission at a cerebellar synapse. J Neurophysiol 2012; 109:1669-80. [PMID: 23255722 DOI: 10.1152/jn.00854.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The sodium/calcium exchanger (NCX) is a widespread transporter that exchanges sodium and calcium ions across excitable membranes. Normally, NCX mainly operates in its "forward" mode, harnessing the electrochemical gradient of sodium ions to expel calcium. During membrane depolarization or elevated internal sodium levels, NCX can instead switch the direction of net flux to expel sodium and allow calcium entry. Such "reverse"-mode NCX operation is frequently implicated during pathological or artificially extended periods of depolarization, not during normal activity. We have used fast calcium imaging, mathematical simulation, and whole cell electrophysiology to study the role of NCX at the parallel fiber-to-Purkinje neuron synapse in the mouse cerebellum. We show that nontraditional, reverse-mode NCX activity boosts the amplitude and duration of parallel fiber calcium transients during short bursts of high-frequency action potentials typical of their behavior in vivo. Simulations, supported by experimental manipulations, showed that accumulation of intracellular sodium drove NCX into reverse mode. This mechanism fueled additional calcium influx into the parallel fibers that promoted synaptic transmission to Purkinje neurons for up to 400 ms after the burst. Thus we provide the first functional demonstration of transient and fast NCX-mediated calcium entry at a major central synapse. This unexpected contribution from reverse-mode NCX appears critical for shaping presynaptic calcium dynamics and transiently boosting synaptic transmission, and is likely to optimize the accuracy of cerebellar information transfer.
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Affiliation(s)
- Chris J Roome
- Department of Physiology, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand
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4
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Brisson CD, Andrew RD. A neuronal population in hypothalamus that dramatically resists acute ischemic injury compared to neocortex. J Neurophysiol 2012; 108:419-30. [PMID: 22514289 DOI: 10.1152/jn.00090.2012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pyramidal neurons (PyNs) of the cortex are highly susceptible to acute stroke damage, yet "lower" brain regions like hypothalamus and brain stem better survive global ischemia. Here we show for the first time that a "lower" neuron population intrinsically resists acute strokelike injury. In rat brain slices deprived of oxygen and glucose (OGD), we imaged anoxic depolarization (AD) as it propagated through neocortex or hypothalamus. AD, the initial electrophysiological event of stroke, is a front of depolarization that drains residual energy in compromised gray matter. The extent of AD reliably determines ensuing cortical damage, but do all CNS neurons generate a robust AD? During 10 min of OGD, PyNs depolarize without functional recovery. In contrast, magnocellular neuroendocrine cells (MNCs) in hypothalamus under identical stress generate a weak and delayed AD, resist complete depolarization, and rapidly repolarize when oxygen and glucose are restored. They recover their membrane potential, input resistance, and spike amplitude and can survive multiple OGD exposures. Two-photon microscopy in slices derived from a fluorescent mouse line confirms this protection, revealing PyN swelling and dendritic beading after OGD, whereas MNCs are not injured. Exposure to the Na(+)-K(+)-ATPase inhibitor ouabain (100 μM) induces AD similar to OGD in both cell types. Moreover, elevated extracellular K(+) concentration ([K(+)](o)) evokes spreading depression (SD), a milder version of AD, in PyNs but not MNCs. Therefore overriding the pump by OGD, ouabain, or elevated [K(+)](o) evokes a propagating depolarization in higher gray matter but not in MNCs. We suggest that variation in Na(+)-K(+)-ATPase pump efficiency during ischemia injury determines whether a neuronal type succumbs to or resists stroke.
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Affiliation(s)
- C Devin Brisson
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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5
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Yuste R, MacLean J, Vogelstein J, Paninski L. Imaging action potentials with calcium indicators. Cold Spring Harb Protoc 2011; 2011:985-9. [PMID: 21807854 DOI: 10.1101/pdb.prot5650] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Cross JL, Meloni BP, Bakker AJ, Lee S, Knuckey NW. Modes of Neuronal Calcium Entry and Homeostasis following Cerebral Ischemia. Stroke Res Treat 2010; 2010:316862. [PMID: 21052549 PMCID: PMC2968719 DOI: 10.4061/2010/316862] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 09/29/2010] [Indexed: 01/14/2023] Open
Abstract
One of the major instigators leading to neuronal cell death and brain damage following cerebral ischemia is calcium dysregulation. The neuron's inability to maintain calcium homeostasis is believed to be a result of increased calcium influx and impaired calcium extrusion across the plasma membrane. The need to better understand the cellular and biochemical mechanisms of calcium dysregulation contributing to neuronal loss following stroke/cerebral ischemia is essential for the development of new treatments in order to reduce ischemic brain injury. The aim of this paper is to provide a concise overview of the various calcium influx pathways in response to ischemia and how neuronal cells attempts to overcome this calcium overload.
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Affiliation(s)
- J L Cross
- Centre for Neuromuscular and Neurological Disorders, Australian Neuromuscular Research Institute, University of Western Australia, WA 6009, Australia
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7
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Chao D, Xia Y. Ionic storm in hypoxic/ischemic stress: can opioid receptors subside it? Prog Neurobiol 2009; 90:439-70. [PMID: 20036308 DOI: 10.1016/j.pneurobio.2009.12.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 09/10/2009] [Accepted: 12/17/2009] [Indexed: 12/17/2022]
Abstract
Neurons in the mammalian central nervous system are extremely vulnerable to oxygen deprivation and blood supply insufficiency. Indeed, hypoxic/ischemic stress triggers multiple pathophysiological changes in the brain, forming the basis of hypoxic/ischemic encephalopathy. One of the initial and crucial events induced by hypoxia/ischemia is the disruption of ionic homeostasis characterized by enhanced K(+) efflux and Na(+)-, Ca(2+)- and Cl(-)-influx, which causes neuronal injury or even death. Recent data from our laboratory and those of others have shown that activation of opioid receptors, particularly delta-opioid receptors (DOR), is neuroprotective against hypoxic/ischemic insult. This protective mechanism may be one of the key factors that determine neuronal survival under hypoxic/ischemic condition. An important aspect of the DOR-mediated neuroprotection is its action against hypoxic/ischemic disruption of ionic homeostasis. Specially, DOR signal inhibits Na(+) influx through the membrane and reduces the increase in intracellular Ca(2+), thus decreasing the excessive leakage of intracellular K(+). Such protection is dependent on a PKC-dependent and PKA-independent signaling pathway. Furthermore, our novel exploration shows that DOR attenuates hypoxic/ischemic disruption of ionic homeostasis through the inhibitory regulation of Na(+) channels. In this review, we will first update current information regarding the process and features of hypoxic/ischemic disruption of ionic homeostasis and then discuss the opioid-mediated regulation of ionic homeostasis, especially in hypoxic/ischemic condition, and the underlying mechanisms.
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Affiliation(s)
- Dongman Chao
- Yale University School of Medicine, Department of Pediatrics, New Haven, CT 06520, USA
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8
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Li G, Olson JE. Purinergic activation of anion conductance and osmolyte efflux in cultured rat hippocampal neurons. Am J Physiol Cell Physiol 2008; 295:C1550-60. [PMID: 18923056 DOI: 10.1152/ajpcell.90605.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The majority of mammalian cells demonstrate regulatory volume decrease (RVD) following swelling caused by hyposmotic exposure. A critical signal initiating RVD is activation of nucleotide receptors by ATP. Elevated extracellular ATP in response to cytotoxic cell swelling during pathological conditions also may initiate loss of taurine and other intracellular osmolytes via anion channels. This study characterizes neuronal ATP-activated anion current and explores its role in net loss of amino acid osmolytes. To isolate anion currents, we used CsCl as the major electrolyte in patch electrode and bath solutions and blocked residual cation currents with NiCl(2) and tetraethylammonium. Anion currents were activated by extracellular ATP with a K(m) of 70 microM and increased over fourfold during several minutes of ATP exposure, reaching a maximum after 9.0 min (SD 4.2). The currents were blocked by inhibitors of nucleotide receptors and volume-regulated anion channels (VRAC). Currents showed outward rectification and inactivation at highly depolarizing membrane potentials, characteristics of swelling-activated anion currents. P2X agonists failed to activate the anion current, and an inhibitor of P2X receptors did not block the effect of ATP. Furthermore, current activation was observed with extracellular ADP and 2-(methylthio)adenosine 5'-diphosphate, a P2Y(1) receptor-specific agonist. Much less current activation was observed with extracellular UTP, suggesting the response is mediated predominantly by P2Y(1) receptors. ATP caused a dose-dependent loss of taurine and alanine that could be blocked by inhibitors of VRAC. ATP did not inhibit the taurine uptake transporter. Thus extracellular ATP triggers a loss of intracellular organic osmolytes via activation of anion channels. This mechanism may facilitate neuronal volume homeostasis during cytotoxic edema.
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Affiliation(s)
- Guangze Li
- Dept. of Emergency Medicine, Wright State Univ., Boonshoft School of Medicine, Kettering, OH 45429, USA
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9
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Krnjević K. Electrophysiology of cerebral ischemia. Neuropharmacology 2008; 55:319-33. [DOI: 10.1016/j.neuropharm.2008.01.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 12/31/2007] [Accepted: 01/08/2008] [Indexed: 12/20/2022]
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10
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Jeon D, Chu K, Jung KH, Kim M, Yoon BW, Lee CJ, Oh U, Shin HS. Na+/Ca2+ exchanger 2 is neuroprotective by exporting Ca2+ during a transient focal cerebral ischemia in the mouse. Cell Calcium 2008; 43:482-91. [PMID: 17884163 DOI: 10.1016/j.ceca.2007.08.003] [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] [Received: 05/12/2007] [Revised: 07/28/2007] [Accepted: 08/08/2007] [Indexed: 11/15/2022]
Abstract
Na(+)/Ca(2+) exchanger (NCX), by mediating Na(+) and Ca(2+) fluxes bi-directionally, assumes a role in controlling the Ca(2+) homeostasis in the ischemic brain. It has been suggested that the three isoforms of NCX (NCX1, 2 and 3) may be differentially involved in permanent cerebral ischemia. However, the role of NCX2 has not been defined in ischemic reperfusion injury after a transient focal cerebral ischemia. Furthermore, it is not known whether NCX2 imports or exports intracellular Ca(2+) ([Ca(2+)](i)) following ischemia and reperfusion. To define the role of NCX2 in ischemia and reperfusion, we examined mice lacking NCX2, in vivo and in vitro. After an in vitro ischemia, a significantly slower recovery in population spike amplitudes, a sustained elevation of [Ca(2+)](i) and an increased membrane depolarization were developed in the NCX2-deficient hippocampus. Moreover, a transient focal cerebral ischemia in vivo produced a larger infarction and more cell death in the NCX2-deficient mouse brain. In particular, in the wild type brain, NCX2-expressing neurons were largely spared from cell death after ischemia. Our results suggest that NCX2 exports Ca(2+) in ischemia and thus protects neuronal cells from death by reducing [Ca(2+)](i) in the adult mouse brain.
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Affiliation(s)
- Daejong Jeon
- Center for Neural Science, Korea Institute of Science and Technology, Seoul, Republic of Korea
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11
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Tian D, Dmitrieva RI, Doris PA, Crary JF, Sondhi R, Sacktor TC, Bergold PJ. Protein kinase M zeta regulation of Na/K ATPase: a persistent neuroprotective mechanism of ischemic preconditioning in hippocampal slice cultures. Brain Res 2008; 1213:127-39. [PMID: 18455703 DOI: 10.1016/j.brainres.2008.03.046] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/19/2008] [Accepted: 03/20/2008] [Indexed: 01/21/2023]
Abstract
In ischemic preconditioning, a sublethal ischemic insult protects neurons from subsequent ischemia. In organotypic hippocampal slice cultures a sublethal 5-minute hypoxia-hypoglycemia treatment prevented neuronal loss after a 10-minute experimental ischemic (EI) treatment of hypoxia-hypoglycemia. Whereas preconditioning protected against EI given 24 h later, it did not protect when EI was given 2 h later, suggesting a slow development of neuroprotection. This model identified two regulators of ischemic preconditioning: the atypical protein kinase M zeta (PKMzeta), and the Na/K ATPase. Two hours following preconditioning, when there was no neuroprotection, Na/K ATPase activity was unchanged. In contrast, Na/K ATPase activity significantly increased 24 h after the preconditioning treatment. Elevated Na/K ATPase activity was accompanied by increased surface expression of the alpha1 and alpha2 isoforms of the Na/K ATPase. Similarly, active PKMzeta levels were increased at 24 h, but not 2 h, after preconditioning. PKMzeta overexpression by sindbis virus vectors also increased Na/K ATPase activity. To examine PKMzeta regulation of Na/K ATPase, occlusion experiments were performed using marinobufagenin to inhibit alpha1, dihydroouabain to inhibit alpha2/3 and a zeta-pseudosubstrate peptide to inhibit PKMzeta. These experiments showed that PKMzeta regulated both the activity and surface expression of the alpha1 isoform of the Na/K ATPase. Marinobufagenin, dihydroouabain, and zeta-pseudosubstrate peptide were used to determine if PKMzeta or the alpha1 and alpha2 Na/K ATPase isoforms protected neurons. All three compounds blocked neuroprotection following ischemic preconditioning. PKMzeta levels were elevated 3 days after ischemic preconditioning. These data indicate key roles of PKMzeta and Na/K ATPase in ischemic preconditioning.
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Affiliation(s)
- Dezhi Tian
- Program in Neural and Behavioral Science, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York-Downstate Medical Center, Brooklyn, NY 11203, USA
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12
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Kim JH, Park YK, Kim JH, Kwon TH, Chung HS. Transient recovery of synaptic transmission is related to rapid energy depletion during hypoxia. Neurosci Lett 2006; 400:1-6. [PMID: 16644112 DOI: 10.1016/j.neulet.2006.01.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 01/19/2006] [Accepted: 01/20/2006] [Indexed: 11/25/2022]
Abstract
Transient recovery (TR) of evoked synaptic potential during the late stage of hypoxic hypoglycemia (HH) insult was investigated in rat hippocampal slices using extracellular recording methods. TR was observed in association with a rapid deterioration of antidromic population spikes (aPSs) following HH insult. TR was not elicited in normoglycemic hypoxia (NH), in which a gradual and delayed deterioration of aPSs was noted. TR was not modulated by either Ca(2+)- or PKC-dependent processes. When a glycolytic inhibitor was added, NH resulted in a rapid deterioration of aPSs and prompted appearance of TR. TR was also seen in slices using lactate to generate energy via oxidative phosphorylation, when hypoxic conditions were subsequently created. Other pharmacological interventions that aimed to cause rapid deterioration of aPSs without depleting energy stores failed to reproduce TR. The evidence thus suggests that the underlying mechanisms of TR appearance during HH insult are highly correlated with rapid energy depletion.
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Affiliation(s)
- Joo Han Kim
- Department of Neurosurgery, College of Medicine, Korea University, Seoul, Korea
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Hwang IK, Yoo KY, Kim DW, Kang TC, Choi SY, Kwon YG, Han BH, Kim JS, Won MH. Na+/Ca2+ exchanger 1 alters in pyramidal cells and expresses in astrocytes of the gerbil hippocampal CA1 region after ischemia. Brain Res 2006; 1086:181-90. [PMID: 16626636 DOI: 10.1016/j.brainres.2006.02.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 02/08/2006] [Accepted: 02/10/2006] [Indexed: 10/24/2022]
Abstract
Alterations of immunoreactivity and protein contents of Na(+)/Ca(2+) exchanger 1 (NCX1) were observed in the gerbil hippocampus proper after 5 min of transient forebrain ischemia. NCX1 immunoreactivity was significantly changed in the hippocampal CA1 region, but not in the CA2/3 region after ischemia/reperfusion. In the sham-operated group, NCX1 immunoreactivity was mainly detected in CA1 pyramidal cells. However, 30 min after ischemia/reperfusion, NCX1 immunoreactivity was significantly decreased and then increased at 1 day after ischemia. At this time, NCX1 immunoreactivity in CA1 pyramidal cells was similar to that of the sham-operated group. At 3 days after ischemia, NCX1 immunoreactivity was significantly reduced in the CA1 region compared to that of the sham-operated group and NCX1 immunoreactivity was significantly increased again 4 days after ischemia. Thereafter, NCX1 immunoreactivity was decreased time-dependently in ischemia groups. Between 15 min and 6 h post-ischemia, NCX1 immunoreactivity was expressed in astrocytes in the strata oriens and radiatum of the CA1 region. From 3 days post-ischemia, NCX1 immunoreactivity was expressed in astrocytes in the strata oriens and radiatum. Ischemia-induced changes in NCX1 protein contents in the hippocampus proper concurred with immunohistochemical data post-ischemia. Our results suggest that changes in NCX1 in CA1 pyramidal cells and astrocytes after ischemia are associated with intracellular Na(+) concentrations and that NCX1 may induce an intracellular calcium overload, which may be related to neuronal death.
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Affiliation(s)
- In Koo Hwang
- Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, South Korea
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Albrecht J, Hanganu IL, Heck N, Luhmann HJ. Oxygen and glucose deprivation induces major dysfunction in the somatosensory cortex of the newborn rat. Eur J Neurosci 2006; 22:2295-305. [PMID: 16262667 DOI: 10.1111/j.1460-9568.2005.04398.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanisms and functional consequences of ischemia-induced injury during perinatal development are poorly understood. Subplate neurons (SPn) play a central role in early cortical development and a pathophysiological impairment of these neurons may have long-term detrimental effects on cortical function. The acute and long-term consequences of combined oxygen and glucose deprivation (OGD) were investigated in SPn and compared with OGD-induced dysfunction of immature layer V pyramidal cortical neurons (PCn) in somatosensory cortical slices from postnatal day (P)0-4 rats. OGD for 50 min followed by a 10-24-h period of normal oxygenation and glucose supply in vitro or in culture led to pronounced caspase-3-dependent apoptotic cell death in all cortical layers. Whole-cell patch-clamp recordings revealed that the majority of SPn and PCn responded to OGD with an initial long-lasting ischemic hyperpolarization accompanied by a decrease in input resistance (R(in)), followed by an ischemic depolarization (ID). Upon reoxygenation and glucose supply, the recovery of the membrane potential and R(in) was followed by a Na+/K+-ATPase-dependent postischemic hyperpolarization, and in almost half of the investigated SPn and PCn by a postischemic depolarization. Whereas neither a moderate (2.5 mm) nor a high (4.8 mm) increase in extracellular magnesium concentration protected the SPn from OGD-induced dysfunction, blockade of NMDA receptors with MK-801 led to a significant delay and decrease of the ID. Our data demonstrate that OGD induces apoptosis and a profound dysfunction in SPn and PCn, and underline the critical role of NMDA receptors in early ischemia-induced neuronal damage.
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Affiliation(s)
- Juliane Albrecht
- Institute of Physiology & Pathophysiology, Johannes Gutenberg University, Duesbergweg 6, D-55128 Mainz, Germany
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15
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Niiyama S, Tanaka E, Tsuji S, Murai Y, Satani M, Sakamoto H, Takahashi K, Kuroiwa M, Yamada A, Noguchi M, Higashi H. Neuroprotective mechanisms of lidocaine against in vitro ischemic insult of the rat hippocampal CA1 pyramidal neurons. Neurosci Res 2005; 53:271-8. [PMID: 16102862 DOI: 10.1016/j.neures.2005.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 07/11/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
To compare neuroprotective effects of lidocaine and procaine against ischemic insult, intracellular recordings were made from rat hippocampal CA1 pyramidal neurons in slice preparations. Superfusion of the slices with oxygen- and glucose-deprived medium (in vitro ischemia) produced a rapid depolarization 6 min from the onset. When oxygen and glucose were reintroduced, the membrane depolarized further until it reached 0 mV, and thereafter the membrane showed no functional recovery. Pretreatment with lidocaine (10 microM), but not procaine (50 microM), restored the membrane potential after the reintroduction of oxygen and glucose. Lidocaine, compared to procaine, significantly inhibited the reduction in both tissue ATP content and flavoprotein fluorescence during and after in vitro ischemia. Under electron microscopy, only lidocaine well preserved the structure of mitochondria in the CA1 pyramidal cell body. Extracellular recordings revealed that procaine reduced the field postsynaptic potential whereas lidocaine augmented it. Both drugs reduced the presynaptic volley dose-dependently. Neither lidocaine nor procaine significantly affected a rapid rise of the intracellular Ca2+ level produced by in vitro ischemia in the CA1 region. All the results suggest that the neuroprotective lidocaine action is due to the protection of the mitochondria to maintain the tissue ATP content during and after in vitro ischemia.
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Affiliation(s)
- S Niiyama
- Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
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16
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Hampson RE, Zhuang SY, Weiner JL, Deadwyler SA. Functional significance of cannabinoid-mediated, depolarization-induced suppression of inhibition (DSI) in the hippocampus. J Neurophysiol 2003; 90:55-64. [PMID: 12649318 DOI: 10.1152/jn.01161.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A number of recent studies have demonstrated that a well-known form of short-term plasticity at hippocampal GABAergic synapses, called depolarization-induced suppression of inhibition (DSI), is in fact mediated by the retrograde actions of endocannabinoids released in response to depolarization of the postsynaptic cells. These studies suggest that endogenous cannabinoids may play an important role in regulating inhibitory tone in the mammalian CNS. Despite the widespread interest and potential physiological importance of DSI, many questions regarding the physiological relevance of DSI remain. To that end, this study set out to define the specific limiting conditions that could elicit DSI at GABAergic synapses in CA1 hippocampal pyramidal neurons and to determine if DSI could be elicited with pulse trains that mimic hippocampal cell-firing patterns that occur in vivo. Whole cell recordings from hippocampal neurons under voltage-clamp configuration were made in rat hippocampal slices. Spontaneous and evoked gamma-aminobutyric acid-A (GABAA) receptor-mediated inhibitory postsynaptic currents (sIPSCs and eIPSCs, respectively) were recorded prior to and following depolarization of CA1 hippocampal pyramidal cells. Depolarizing voltage pulses were shaped to evoke currents in QX-314-treated cells similar to those accompanying single spontaneous voltage-clamped action potentials recorded from the soma. Attempts were made to elicit DSI with trains of these pulses that mimicked hippocampal cell firing patterns in vivo, for instance, when animals traverse place fields or are performing a short-term memory task. DSI could not be elicited by such pulse trains or by a number of other combinations of behaviorally specific firing parameters. The minimum duration of depolarization necessary to elicit DSI in hippocampal neurons determined by paired-pulse manipulation was 50 -75 ms at a critical interval of 20 -30 ms between pulse pairs. Under the conditions tested, the normal firing patterns of hippocampal neurons that occur in vivo do not appear to elicit DSI.
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Affiliation(s)
- Robert E Hampson
- Wake Forest University Health Sciences, Department of Physiology and Pharmacology, Winston-Salem, North Carolina 27157, USA
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