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Kawakita F, Nakano F, Kanamaru H, Asada R, Suzuki H. Anti-Apoptotic Effects of AMPA Receptor Antagonist Perampanel in Early Brain Injury After Subarachnoid Hemorrhage in Mice. Transl Stroke Res 2024; 15:462-475. [PMID: 36757633 DOI: 10.1007/s12975-023-01138-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 01/12/2023] [Accepted: 02/05/2023] [Indexed: 02/10/2023]
Abstract
This study was aimed to investigate if acute neuronal apoptosis is induced by activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptors (AMPARs) and inhibited by a clinically available selective AMPAR antagonist and antiepileptic drug perampanel (PER) in subarachnoid hemorrhage (SAH), and if the mechanisms include upregulation of an inflammation-related matricellular protein periostin. Sham-operated and endovascular perforation SAH mice randomly received an administration of 3 mg/kg PER or the vehicle intraperitoneally. Post-SAH neurological impairments and increased caspase-dependent neuronal apoptosis were associated with activation of AMPAR subunits GluA1 and GluA2, and upregulation of periostin and proinflammatory cytokines interleukins-1β and -6, all of which were suppressed by PER. PER also inhibited post-SAH convulsion-unrelated increases in the total spectral power on video electroencephalogram (EEG) monitoring. Intracerebroventricularly injected recombinant periostin blocked PER's anti-apoptotic effects on neurons. An intracerebroventricular injection of a selective agonist for GluA1 and GluA2 aggravated neurological impairment, neuronal apoptosis as well as periostin upregulation, but did not increase the EEG total spectral power after SAH. A higher dosage (10 mg/kg) of PER had even more anti-apoptotic effects compared with 3 mg/kg PER. Thus, this study first showed that AMPAR activation causes post-SAH neuronal apoptosis at least partly via periostin upregulation. A clinically available AMPAR antagonist PER appears to be neuroprotective against post-SAH early brain injury through the anti-inflammatory and anti-apoptotic effects, independent of the antiepileptic action, and deserves further study.
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Affiliation(s)
- Fumihiro Kawakita
- Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Mie , 514-8507, Tsu, Japan
| | - Fumi Nakano
- Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Mie , 514-8507, Tsu, Japan
| | - Hideki Kanamaru
- Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Mie , 514-8507, Tsu, Japan
| | - Reona Asada
- Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Mie , 514-8507, Tsu, Japan
| | - Hidenori Suzuki
- Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Mie , 514-8507, Tsu, Japan.
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Bayat M, Karimi N, Karami M, Haghighi AB, Bayat K, Akbari S, Haghani M. Chronic exposure to 2.45 GHz microwave radiation improves cognition and synaptic plasticity impairment in vascular dementia model. Int J Neurosci 2023; 133:111-122. [PMID: 33635159 DOI: 10.1080/00207454.2021.1896502] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Purpose: In this study, we evaluated the effects of 2.45 GHz microwave radiation on cognitive dysfunction induced by vascular dementia (VaD).Methods: The VaD was induced by bilateral-common carotid occlusion (2-VO). The rats were divided into 4 groups including: control (n = 6), sham (n = 6), 2-VO (n = 8), and 2-VO + Wi-Fi (n = 10) groups. Wi-Fi modem centrally located at the distance of 25 cm from the animal's cages and the animals were continuously exposed to Wi-Fi signal while they freely moved in the cage (2 h/day for forty-five days). Therefore, the power density (PD) and specific absorption rate value (SAR) decreased at a distance of 25 to 60 cm (PD = 0.018 to 0.0032 mW/cm2, SAR = 0.0346 to 0.0060 W/Kg). The learning, memory, and hippocampal synaptic-plasticity were evaluated by radial arm maze (RAM), passive avoidance (PA), and field-potential recording respectively. The number of hippocampal CA1 cells was also assessed by giemsa staining.Results: Our results showed that VaD model led to impairment in the spatial learning and memory performance in RAM and PA that were associated with long-term potentiation (LTP) impairment, decrease of basal-synaptic transmission (BST), increase of GABA transmission, and decline of neurotransmitter release-probability as well as hippocampal cell loss. Notably, chronic Wi-Fi exposure significantly recovered the learning-memory performance, LTP induction, and cell loss without any effect on BST.Conclusions: The LTP recovery by Wi-Fi in the 2-VO rats was probably related to significant increases in the hippocampal CA1 neuronal density, partial recovery of neurotransmitter release probability, and reduction of GABA transmissiSon as evident by rescue of paired-pulse ratio 10 ms.
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Affiliation(s)
- Mahnaz Bayat
- Clinical Neurology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Narges Karimi
- Department of Physiology, the Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Karami
- Department of Physiology, the Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Kamjoo Bayat
- Department of Physics, K. N. Toosi University of Technology, Tehran, Iran
| | - Somayeh Akbari
- Department of Physiology, the Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Masoud Haghani
- Department of Physiology, the Medical School, Shiraz University of Medical Sciences, Shiraz, Iran.,Histomorphometry and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran
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Sharifi MD, Karimi N, Karami M, Borhani Haghighi A, Shabani M, Bayat M. The Minocycline Ameliorated the Synaptic Plasticity Impairment in Vascular Dementia. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2022; 20:435-449. [PMID: 35194458 PMCID: PMC8842628 DOI: 10.22037/ijpr.2020.113942.14576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Chronic cerebral hypoperfusion (CCH) leads to vascular dementia with progressive hippocampal damage and cognitive impairments. In the present study, we compared early and late Minocycline (MINO) treatment on cognitive function, long and short-term synaptic-plasticity following CCH. We used bilateral common carotid arteries occlusion model (2VO) for induction of hypoperfusion. Male Sprague-Dawley rats were divided into 5 following groups (each having 2 subgroups): 2VO + V (vehicle), 2VO+MINO-E (early treatment of MINO on days 0 to 3 after 2VO), 2VO+MINO-L (late-treatment on days 21 to 32 after 2VO), control, and sham. Passive-avoidance (PA) and radial arm maze (RAM) tests were used to investigate learning and memory. Long term and short term synaptic plasticity were assessed by field potential recording, the brains were removed after recording and preserved for histological study to count pyramidal cells in CA1 region.Cerebral hypoperfusion could impair memory performance, synaptic plasticity, and basal synaptic transmission (BST) along with hippocampal cell loss. Thus, we found a significant reduction in step-through latency (STL) of PA test with a higher number of working and reference errors in RAM in CCH rats. However, only late treatment with MINO improved memory performance, synaptic plasticity, hippocampal cell loss, and increased neurotransmitter pool (NP) in CCH rats, but early treatment could not produce long-lasting beneficial effects 32 days after 2VO. MINO may improve synaptic plasticity and memory performance in hypo-perfused rats directly and indirectly by increasing NP and/or suppressing inflammatory factors, respectively.
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Affiliation(s)
- Mohammad Davood Sharifi
- Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Narges Karimi
- Department of Physiology, The Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Karami
- Department of Physiology, The Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Mohammad Shabani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Mahnaz Bayat
- Clinical Neurology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran
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4
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Samanipour R, Tahmooressi H, Rezaei Nejad H, Hirano M, Shin SR, Hoorfar M. A review on 3D printing functional brain model. BIOMICROFLUIDICS 2022; 16:011501. [PMID: 35145569 PMCID: PMC8816519 DOI: 10.1063/5.0074631] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 12/31/2021] [Indexed: 05/08/2023]
Abstract
Modern neuroscience increasingly relies on 3D models to study neural circuitry, nerve regeneration, and neural disease. Several different biofabrication approaches have been explored to create 3D neural tissue model structures. Among them, 3D bioprinting has shown to have great potential to emerge as a high-throughput/high precision biofabrication strategy that can address the growing need for 3D neural models. Here, we have reviewed the design principles for neural tissue engineering. The main challenge to adapt printing technologies for biofabrication of neural tissue models is the development of neural bioink, i.e., a biomaterial with printability and gelation properties and also suitable for neural tissue culture. This review shines light on a vast range of biomaterials as well as the fundamentals of 3D neural tissue printing. Also, advances in 3D bioprinting technologies are reviewed especially for bioprinted neural models. Finally, the techniques used to evaluate the fabricated 2D and 3D neural models are discussed and compared in terms of feasibility and functionality.
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Affiliation(s)
| | - Hamed Tahmooressi
- Department of Mechanical Engineering, University of British Columbia, Kelowna, British Columbia V1V 1V7, Canada
| | - Hojatollah Rezaei Nejad
- Department of Electrical and Computer Engineering, Tufts University, 161 College Avenue, Medford, Massachusetts 02155, USA
| | | | - Su-Royn Shin
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02139, USA
- Authors to whom correspondence should be addressed: and
| | - Mina Hoorfar
- Faculty of Engineering, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
- Authors to whom correspondence should be addressed: and
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Shi Z, Lei Z, Wu F, Xia L, Ruan Y, Xu ZC. Increased Sestrin3 Contributes to Post-ischemic Seizures in the Diabetic Condition. Front Neurosci 2021; 14:591207. [PMID: 33519354 PMCID: PMC7843462 DOI: 10.3389/fnins.2020.591207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/14/2020] [Indexed: 11/13/2022] Open
Abstract
Seizures are among the most common neurological sequelae of stroke, and diabetes notably increases the incidence of post-ischemic seizures. Recent studies have indicated that Sestrin3 (SESN3) is a regulator of a proconvulsant gene network in human epileptic hippocampus. But the association of SESN3 and post-ischemic seizures in diabetes remains unclear. The present study aimed to reveal the involvement of SESN3 in seizures following transient cerebral ischemia in diabetes. Diabetes was induced in adult male mice and rats via intraperitoneal injection of streptozotocin (STZ). Forebrain ischemia (15 min) was induced by bilateral common carotid artery occlusion, the 2-vessel occlusion (2VO) in mice and 4-vessel occlusion (4VO) in rats. Our results showed that 59% of the diabetic wild-type mice developed seizures after ischemia while no seizures were observed in non-diabetic mice. Although no apparent cell death was detected in the hippocampus of seizure mice within 24 h after the ischemic insult, the expression of SESN3 was significantly increased in seizure diabetic mice after ischemia. The post-ischemic seizure incidence significantly decreased in SESN3 knockout mice. Furthermore, all diabetic rats suffered from post-ischemic seizures and non-diabetic rats have no seizures. Electrophysiological recording showed an increased excitatory synaptic transmission and intrinsic membrane excitability in dentate granule cells of the rat hippocampus, together with decreased I A currents and Kv4.2 expression levels. The above results suggest that SESN3 up-regulation may contribute to neuronal hyperexcitability and seizure generation in diabetic animals after ischemia. Further studies are needed to explore the molecular mechanism of SESN3 in seizure generation after ischemia in diabetic conditions.
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Affiliation(s)
- Zhongshan Shi
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States.,Guangdong-Hongkong-Macau Institute for CNS Regeneration, Jinan University, Guangzhou, China.,Department of Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhigang Lei
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Fan Wu
- Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Luoxing Xia
- Guangdong-Hongkong-Macau Institute for CNS Regeneration, Jinan University, Guangzhou, China
| | - Yiwen Ruan
- Guangdong-Hongkong-Macau Institute for CNS Regeneration, Jinan University, Guangzhou, China.,Jiangsu Province Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Zao C Xu
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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Neural Stem Cell Transplantation Induces Stroke Recovery by Upregulating Glutamate Transporter GLT-1 in Astrocytes. J Neurosci 2017; 36:10529-10544. [PMID: 27733606 DOI: 10.1523/jneurosci.1643-16.2016] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 08/09/2016] [Indexed: 01/10/2023] Open
Abstract
Ischemic stroke is the leading cause of disability, but effective therapies are currently widely lacking. Recovery from stroke is very much dependent on the possibility to develop treatments able to both halt the neurodegenerative process as well as to foster adaptive tissue plasticity. Here we show that ischemic mice treated with neural precursor cell (NPC) transplantation had on neurophysiological analysis, early after treatment, reduced presynaptic release of glutamate within the ipsilesional corticospinal tract (CST), and an enhanced NMDA-mediated excitatory transmission in the contralesional CST. Concurrently, NPC-treated mice displayed a reduced CST degeneration, increased axonal rewiring, and augmented dendritic arborization, resulting in long-term functional amelioration persisting up to 60 d after ischemia. The enhanced functional and structural plasticity relied on the capacity of transplanted NPCs to localize in the peri-ischemic and ischemic area, to promote the upregulation of the glial glutamate transporter 1 (GLT-1) on astrocytes and to reduce peri-ischemic extracellular glutamate. The upregulation of GLT-1 induced by transplanted NPCs was found to rely on the secretion of VEGF by NPCs. Blocking VEGF during the first week after stroke reduced GLT-1 upregulation as well as long-term behavioral recovery in NPC-treated mice. Our results show that NPC transplantation, by modulating the excitatory-inhibitory balance and stroke microenvironment, is a promising therapy to ameliorate disability, to promote tissue recovery and plasticity processes after stroke. SIGNIFICANCE STATEMENT Tissue damage and loss of function occurring after stroke can be constrained by fostering plasticity processes of the brain. Over the past years, stem cell transplantation for repair of the CNS has received increasing interest, although underlying mechanism remain elusive. We here show that neural stem/precursor cell transplantation after ischemic stroke is able to foster axonal rewiring and dendritic plasticity and to induce long-term functional recovery. The observed therapeutic effect of neural precursor cells seems to underlie their capacity to upregulate the glial glutamate transporter on astrocytes through the vascular endothelial growth factor inducing favorable changes in the electrical and molecular stroke microenvironment. Cell-based approaches able to influence plasticity seem particularly suited to favor poststroke recovery.
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7
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Abstract
This review presents a brief overview of the γ-aminobutyric acid (GABA) system in the developing and mature central nervous system (CNS) and its potential connections to pathologies of the CNS. γ-aminobutyric acid (GABA) is a major neurotransmitter expressed from the embryonic stage and throughout life. At an early developmental stage, GABA acts in an excitatory manner and is implicated in many processes of neurogenesis, including neuronal proliferation, migration, differentiation, and preliminary circuit-building, as well as the development of critical periods. In the mature CNS, GABA acts in an inhibitory manner, a switch mediated by chloride/cation transporter expression and summarized in this review. GABA also plays a role in the development of interstitial neurons of the white matter, as well as in oligodendrocyte development. Although the underlying cellular mechanisms are not yet well understood, we present current findings for the role of GABA in neurological diseases with characteristic white matter abnormalities, including anoxic-ischemic injury, periventricular leukomalacia, and schizophrenia. Development abnormalities of the GABAergic system appear particularly relevant in the etiology of schizophrenia. This review also covers the potential role of GABA in mature brain injury, namely transient ischemia, stroke, and traumatic brain injury/post-traumatic epilepsy.
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Affiliation(s)
- Connie Wu
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
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8
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Shiba M, Fujimoto M, Imanaka-Yoshida K, Yoshida T, Taki W, Suzuki H. Tenascin-C causes neuronal apoptosis after subarachnoid hemorrhage in rats. Transl Stroke Res 2014; 5:238-47. [PMID: 24481545 DOI: 10.1007/s12975-014-0333-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 01/15/2014] [Accepted: 01/16/2014] [Indexed: 10/25/2022]
Abstract
The role of tenascin-C (TNC), a matricellular protein, in brain injury is unknown. The aim of this study was to examine if TNC causes neuronal apoptosis after subarachnoid hemorrhage (SAH), a deadly cerebrovascular disorder, using imatinib mesylate (a selective inhibitor of platelet-derived growth factor receptor [PDGFR] that is reported to suppress TNC induction) and recombinant TNC. SAH by endovascular perforation caused caspase-dependent neuronal apoptosis in the cerebral cortex irrespective of cerebral vasospasm development at 24 and 72 h post-SAH, associated with PDGFR activation, mitogen-activated protein kinases (MAPKs) activation, and TNC induction in rats. PDGFR inactivation by an intraperitoneal injection of imatinib mesylate prevented neuronal apoptosis, as well as MAPKs activation and TNC induction in the cerebral cortex at 24 h. A cisternal injection of recombinant TNC reactivated MAPKs and abolished anti-apoptotic effects of imatinib mesylate. The TNC injection also induced TNC itself in SAH brain, which may internally augment neuronal apoptosis after SAH. These findings suggest that TNC upregulation by PDGFR activation causes neuronal apoptosis via MAPK activation, and that the positive feedback mechanisms may exist to augment neuronal apoptosis after SAH. TNC-induced neuronal apoptosis would be a new target to improve outcome after SAH.
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Affiliation(s)
- Masato Shiba
- Department of Neurosurgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
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Wang Y, MA T, Zhou L, Li M, Sun XJ, Wang YG, Gu S. Penehyclidine hydrochloride protects against oxygen and glucose deprivation injury by modulating amino acid neurotransmitters release. Neurol Res 2013; 35:1022-8. [DOI: 10.1179/1743132813y.0000000247] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- Yun Wang
- Department of PharmacologyXuZhou Medical College, XuZhou, Jiangsu, China
| | - Tengfei MA
- Department of PharmacologyXuZhou Medical College, XuZhou, Jiangsu, China
| | - Li Zhou
- Key Laboratory for Anesthesiology of Jiangsu ProvinceXuZhou, Jiangsu, China
| | - Mei Li
- Department of PharmacologyXuZhou Medical College, XuZhou, Jiangsu, China
| | - Xiao-Jing Sun
- Department of PharmacologyXuZhou Medical College, XuZhou, Jiangsu, China
| | - Yi-Gang Wang
- Department of PharmacologyXuZhou Medical College, XuZhou, Jiangsu, China
| | - Shuling Gu
- Department of PharmacologyXuZhou Medical College, XuZhou, Jiangsu, China
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Montori S, DosAnjos S, Poole A, Regueiro-Purriños MM, Llorente IL, Darlison MG, Fernández-López A, Martínez-Villayandre B. Differential effect of transient global ischaemia on the levels of γ-aminobutyric acid type A (GABAA) receptor subunit mRNAs in young and older rats. Neuropathol Appl Neurobiol 2012; 38:710-22. [DOI: 10.1111/j.1365-2990.2012.01254.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Anoxic depolarization of hippocampal astrocytes: possible modulation by P2X7 receptors. Neurochem Int 2012; 62:15-22. [PMID: 23147683 DOI: 10.1016/j.neuint.2012.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/31/2012] [Accepted: 11/01/2012] [Indexed: 12/30/2022]
Abstract
Current responses from CA1 neurons and stratum oriens astrocytes were recorded from hippocampal brain slices by means of the whole-cell patch-clamp technique. Anoxic depolarization (AD) was induced by an oxygen/glucose-deprived (OGD) medium also containing sodium iodoacetate and antimycin, in order to block glycolysis and oxidative phosphorylation, respectively. Anoxic depolarization has been reported to be due to the sudden increase of the extracellular K(+) concentration and the accompanying explosive rise in glutamate concentration. We asked ourselves whether the release of ATP activating P2X7 receptors is also involved in the AD. Although, the AD was evoked in absolute synchrony in neurons and astrocytes, and the NMDA receptor antagonistic AP-5 depressed these responses, neither the non-selective P2 receptor antagonist PPADS, nor the highly selective P2X7 receptor antagonist A438079 interfered with the AD or its delay time in neurons/astrocytes after inducing chemical hypoxia. However, A438079, but not PPADS increased in astrocytes the slow inward current observed in a hypoxic medium. It is concluded that ATP co-released with glutamate by hypoxic stimulation has only a minor function in the present brain slice system.
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Chen S, Mohajerani MH, Xie Y, Murphy TH. Optogenetic analysis of neuronal excitability during global ischemia reveals selective deficits in sensory processing following reperfusion in mouse cortex. J Neurosci 2012; 32:13510-9. [PMID: 23015440 PMCID: PMC6621379 DOI: 10.1523/jneurosci.1439-12.2012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/26/2012] [Accepted: 07/21/2012] [Indexed: 12/30/2022] Open
Abstract
We have developed an approach to directly probe neuronal excitability during the period beginning with induction of global ischemia and extending after reperfusion using transgenic mice expressing channelrhodopsin-2 (ChR2) to activate deep layer cortical neurons independent of synaptic or sensory stimulation. Spontaneous, ChR2, or forepaw stimulation-evoked electroencephalogram (EEG) or local field potential (LFP) records were collected from the somatosensory cortex. Within 20 s of ischemia, a >90% depression of spontaneous 0.3-3 Hz EEG and LFP power was detected. Ischemic depolarization followed EEG depression with a ∼2 min delay. Surprisingly, neuronal excitability, as assessed by the ChR2-mediated EEG response, was intact during the period of strong spontaneous EEG suppression and actually increased before ischemic depolarization. In contrast, a decrease in the somatosensory-evoked potential (forepaw-evoked potential, reflecting cortical synaptic transmission) was coincident with the EEG suppression. After 5 min of ischemia, the animal was reperfused, and the ChR2-mediated response mostly recovered within 30 min (>80% of preischemia value). However, the recovery of the somatosensory-evoked potential was significantly delayed compared with the ChR2-mediated response (<40% of preischemia value at 60 min). By assessing intrinsic optical signals in combination with EEG, we found that neuronal excitability approached minimal values when the spreading ischemic depolarization wave propagated to the ChR2-stimulated cortex. Our results indicate that the ChR2-mediated EEG/LFP response recovers much faster than sensory-evoked EEG/LFP activity in vivo following ischemia and reperfusion, defining a period where excitable but synaptically silent neurons are present.
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Affiliation(s)
- Shangbin Chen
- Department of Psychiatry, Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Majid H. Mohajerani
- Department of Psychiatry, Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Yicheng Xie
- Department of Psychiatry, Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Timothy H. Murphy
- Department of Psychiatry, Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Breschi GL, Mastropietro A, Zucca I, Librizzi L, de Curtis M. Penumbra region excitability is not enhanced acutely after cerebral ischemia in the in vitro isolated guinea pig brain. Epilepsia 2011; 53:448-58. [DOI: 10.1111/j.1528-1167.2011.03356.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Li Y, Blanco GD, Lei Z, Xu ZC. Increased GAD expression in the striatum after transient cerebral ischemia. Mol Cell Neurosci 2010; 45:370-7. [PMID: 20659561 DOI: 10.1016/j.mcn.2010.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/05/2010] [Accepted: 07/20/2010] [Indexed: 11/27/2022] Open
Abstract
Striatum is one of the brain regions that are highly sensitive to transient cerebral ischemia. Most of the striatal neurons die shortly after ischemia but interneurons including large aspiny (LA) neurons survive the same insult. Previous studies have shown that inhibitory synaptic transmission is enhanced in LA neurons after ischemia. The present study is aimed at revealing the mechanisms underlying this phenomenon. Immunohistochemical studies and Western blotting were performed to examine the expression of glutamic decarboxylase (GAD), the key enzyme in the synthesis of GABA, in the striatum. GAD65 expression and the number of GAD67-positive cells were increased after ischemia. GAD67-positive cells in the striatum co-expressed GAD65 after ischemia. The increase of GAD67-positive cells did not result from neurogenesis. Double-labeling of GAD67 and SOM indicates that some of the GAD67-positive cells are from the phenotypic shift of pre-existing somatostatin (SOM)-containing GABAergic interneurons after ischemia. Facilitation of inhibitory synaptic transmission by muscimol, a specific GABA(A) receptor agonist, increased the number of survived cells in the striatum after ischemia. Altogether, these data suggest that GAD expression is increased in the striatum after ischemia, which might contribute to the facilitated inhibitory synaptic transmission and the consequent survival of LA neurons.
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Affiliation(s)
- Yan Li
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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15
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Molecular mechanisms of excitotoxicity and their relevance to pathogenesis of neurodegenerative diseases. Acta Pharmacol Sin 2009; 30:379-87. [PMID: 19343058 DOI: 10.1038/aps.2009.24] [Citation(s) in RCA: 728] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A pivotal role for excitotoxicity in neurodegenerative diseases is gaining increasingly more acceptance, but the underlying mechanisms through which it participates in neurodegeneration still need further investigation. Excessive activation of glutamate receptors by excitatory amino acids leads to a number of deleterious consequences, including impairment of calcium buffering, generation of free radicals, activation of the mitochondrial permeability transition and secondary excitotoxicity. Recent studies implicate excitotoxicity in a variety of neuropathological conditions, suggesting that neurodegenerative diseases with distinct genetic etiologies may share excitotoxicity as a common pathogenic pathway. Thus, understanding the pathways involved in excitotoxicity is of critical importance for the future clinical treatment of many neurodegenerative diseases. This review discusses the current understanding of excitotoxic mechanisms and how they are involved in the pathogenesis of neurodegenerative diseases.
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