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Multiple Mild Stimulations Reduce Membrane Distribution of CX3CR1 Promoted by Annexin a1 in Microglia to Attenuate Excessive Dendritic Spine Pruning and Cognitive Deficits Caused by a Transient Ischemic Attack in Mice. Neurosci Bull 2022; 38:753-768. [DOI: 10.1007/s12264-022-00847-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 11/25/2021] [Indexed: 10/18/2022] Open
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Lahti AM, Saloheimo P, Huhtakangas J, Salminen H, Juvela S, Bode MK, Hillbom M, Tetri S. Poststroke epilepsy in long-term survivors of primary intracerebral hemorrhage. Neurology 2017; 88:2169-2175. [PMID: 28476758 DOI: 10.1212/wnl.0000000000004009] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/20/2017] [Indexed: 01/07/2023] Open
Abstract
OBJECTIVE To identify the incidence and predisposing factors for development of poststroke epilepsy (PSE) after primary intracerebral hemorrhage (PICH) during a long-term follow-up. METHODS We performed a retrospective study of patients who had had their first-ever PICH between January 1993 and January 2008 in Northern Ostrobothnia, Finland, and who survived for at least 3 months. These patients were followed up for PSE. The associations between PSE occurrence and sex, age, Glasgow Coma Scale (GCS) score on admission, hematoma location and volume, early seizures, and other possible risk factors for PSE were assessed using the Cox proportional hazards regression model. RESULTS Of the 615 PICH patients who survived for longer than 3 months, 83 (13.5%) developed PSE. The risk of new-onset PSE was highest during the first year after PICH with cumulative incidence of 6.8%. In univariable analysis, the risk factors for PSE were early seizures, subcortical hematoma location, larger hematoma volume, hematoma evacuation, and a lower GCS score on admission, whereas patients with infratentorial hematoma location or hypertension were less likely to develop PSE (all variables p < 0.05). In multivariable analysis, we found subcortical location (hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.35-3.81, p < 0.01) and early seizures (HR 3.63, 95% CI 1.99-6.64, p < 0.01) to be independent risk factors, but patients with hypertension had a lower risk of PSE (HR 0.54, 0.35-0.84, p < 0.01). CONCLUSIONS Subcortical hematoma location and early seizures increased the risk of PSE after PICH in long-term survivors, while hypertension seemed to reduce the risk.
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Affiliation(s)
- Anna-Maija Lahti
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland.
| | - Pertti Saloheimo
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland
| | - Juha Huhtakangas
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland
| | - Henrik Salminen
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland
| | - Seppo Juvela
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland
| | - Michaela K Bode
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland
| | - Matti Hillbom
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland
| | - Sami Tetri
- From the Departments of Neurosurgery (A.-M.L., H.S., S.T.), Neurology (P.S., J.H., M.H.), and Diagnostic Radiology (M.K.B.), Oulu University Hospital; and Department of Clinical Neurosciences (S.J.), University of Helsinki, Finland.
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Stefanidou M, Das RR, Beiser AS, Sundar B, Kelly-Hayes M, Kase CS, Devinsky O, Seshadri S, Friedman D. Incidence of seizures following initial ischemic stroke in a community-based cohort: The Framingham Heart Study. Seizure 2017; 47:105-110. [DOI: 10.1016/j.seizure.2017.03.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/03/2017] [Accepted: 03/16/2017] [Indexed: 10/19/2022] Open
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Jaenisch N, Liebmann L, Guenther M, Hübner CA, Frahm C, Witte OW. Reduced tonic inhibition after stroke promotes motor performance and epileptic seizures. Sci Rep 2016; 6:26173. [PMID: 27188341 PMCID: PMC4870642 DOI: 10.1038/srep26173] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/28/2016] [Indexed: 01/19/2023] Open
Abstract
Stroke survivors often recover from motor deficits, either spontaneously or with the support of rehabilitative training. Since tonic GABAergic inhibition controls network excitability, it may be involved in recovery. Middle cerebral artery occlusion in rodents reduces tonic GABAergic inhibition in the structurally intact motor cortex (M1). Transcript and protein abundance of the extrasynaptic GABAA-receptor complex α4β3δ are concurrently reduced (δ-GABAARs). In vivo and in vitro analyses show that stroke-induced glutamate release activates NMDA receptors, thereby reducing KCC2 transporters and down-regulates δ-GABAARs. Functionally, this is associated with improved motor performance on the RotaRod, a test in which mice are forced to move in a similar manner to rehabilitative training sessions. As an adverse side effect, decreased tonic inhibition facilitates post-stroke epileptic seizures. Our data imply that early and sometimes surprisingly fast recovery following stroke is supported by homeostatic, endogenous plasticity of extrasynaptic GABAA receptors.
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Affiliation(s)
- Nadine Jaenisch
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, Jena University Hospital, D-07743 Jena, Germany
| | - Madlen Guenther
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
| | - Christian A. Hübner
- Institute of Human Genetics, Jena University Hospital, D-07743 Jena, Germany
| | - Christiane Frahm
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
| | - Otto W. Witte
- Hans-Berger Department of Neurology, Jena University Hospital, D-07747 Jena, Germany
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Yang J, Zhang X, Wu Y, Zhao B, Liu X, Pan Y, Liu Y, Ding Y, Qiu M, Wang YZ, Zhao G. Wnt/β-catenin signaling mediates the seizure-facilitating effect of postischemic reactive astrocytes after pentylenetetrazole-kindling. Glia 2016; 64:1083-91. [PMID: 27003605 DOI: 10.1002/glia.22984] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/23/2016] [Accepted: 03/02/2016] [Indexed: 12/19/2022]
Abstract
Ischemia not only leads to tissue damage, but also induces seizures, which in turn worsens the outcome of ischemia. Recent studies have revealed the impaired homeostatic functions of reactive astrocytes, which were thought to facilitate the development of seizures. However, how this phenotype of reactive astrocytes is regulated remains unclear. Here, using pentylenetetrazole (PTZ)-kindling model, we investigated the roles of reactive astrocytes and their intracellular Wnt/β-catenin signaling in the ischemia-increased seizure susceptibility. Our data showed that somatosensory cortical ischemia significantly increased the susceptibility to PTZ-induced seizure. Genetic ablation of Nestin-positive reactive astrocytes significantly decreased the incidence and severity of seizures. By using a Wnt signaling reporter mice line Topgal mice, we found that Wnt/β-catenin signaling was upregulated in reactive astrocytes after ischemia. Depletion of β-catenin in reactive astrocytes significantly decreased the susceptibility of seizures and the expression of c-Fos induced by PTZ in the ischemic cortex. Overexpression of β-catenin in reactive astrocytes, in contrast, significantly increased seizure susceptibility and the expression of c-Fos. Furthermore, the expression of aquaporin-4 (AQP-4) and inwardly rectifying K(+) channel 4.1 (Kir4.1), two molecules reportedly associated with seizure development, was oppositely affected in reactive astrocytes with β-catenin depletion or overexpression. Taken together, these data indicated that astrocytic Wnt/β-catenin signaling accounts, at least partially, for the ischemia-increased seizure susceptibility. Inhibiting Wnt/β-catenin signaling may be utilized in the future for preventing postischemic seizures.
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Affiliation(s)
- Jialei Yang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Neurobiology and Collaborative Innovation Center for Brain Science, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiufen Zhang
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yin Wu
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Bo Zhao
- Department of Neurology, Anning Branch of Lanzhou General Hospital of Lanzhou Military Region, Lanzhou, China
| | - Xunyuan Liu
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yuanhang Pan
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yonghong Liu
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yuqiang Ding
- Key Laboratory of Arrhythmias, Ministry of Education of China, East Hospital, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, China.,Department of Anatomy and Neurobiology, Collaborative Innovation Center for Brain Science, Tongji University School of Medicine, Shanghai, China
| | - Mengsheng Qiu
- Institute of Developmental and Regenerative Biology, Key Laboratory of Organ Development and Regeneration of Zhejiang Province, College of Life Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ya-Zhou Wang
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Gang Zhao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
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Kim JY, Ho H, Kim N, Liu J, Tu CL, Yenari MA, Chang W. Calcium-sensing receptor (CaSR) as a novel target for ischemic neuroprotection. Ann Clin Transl Neurol 2014; 1:851-66. [PMID: 25540800 PMCID: PMC4265057 DOI: 10.1002/acn3.118] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/14/2014] [Accepted: 08/15/2014] [Indexed: 01/04/2023] Open
Abstract
Object Ischemic brain injury is the leading cause for death and long-term disability in patients who suffer cardiac arrest and embolic stroke. Excitotoxicity and subsequent Ca2+-overload lead to ischemic neuron death. We explore a novel mechanism concerning the role of the excitatory extracellular calcium-sensing receptor (CaSR) in the induction of ischemic brain injury. Method Mice were exposed to forebrain ischemia and the actions of CaSR were determined after its genes were ablated specifically in hippocampal neurons or its activities were inhibited pharmacologically. Since the CaSR forms a heteromeric complex with the inhibitory type B γ-aminobutyric acid receptor 1 (GABABR1), we compared neuronal responses to ischemia in mice deficient in CaSR, GABABR1, or both, and in mice injected locally or systemically with a specific CaSR antagonist (or calcilytic) in the presence or absence of a GABABR1 agonist (baclofen). Results Both global and focal brain ischemia led to CaSR overexpression and GABABR1 downregulation in injured neurons. Genetic ablation of Casr genes or blocking CaSR activities by calcilytics rendered robust neuroprotection and preserved learning and memory functions in ischemic mice, partly by restoring GABABR1 expression. Concurrent ablation of Gabbr1 gene blocked the neuroprotection caused by the Casr gene knockout. Coinjection of calcilytics with baclofen synergistically enhanced neuroprotection. This combined therapy remained robust when given 6 h after ischemia. Interpretation Our study demonstrates a novel receptor interaction, which contributes to ischemic neuron death through CaSR upregulation and GABABR1 downregulation, and feasibility of neuroprotection by concurrently targeting these two receptors.
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Affiliation(s)
- Jong Youl Kim
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121 ; Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Hanson Ho
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Nuri Kim
- Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Jialing Liu
- Neurological Surgery, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Chia-Ling Tu
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Midori A Yenari
- Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
| | - Wenhan Chang
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco, California, 94121
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Mild Hypothermia Suppresses Calcium-Sensing Receptor (CaSR) Induction Following Forebrain Ischemia While Increasing GABA-B Receptor 1 (GABA-B-R1) Expression. Transl Stroke Res 2013; 2:195-201. [PMID: 21731589 DOI: 10.1007/s12975-011-0082-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Hypothermia improves neurological outcome from cardiac arrest. The mechanisms of protection are multifold, but identifying some may be useful in exploring potential therapeutic targets. The extracellular calcium-sensing receptor (CaSR) was originally found in parathyroid cells in which the receptor senses minute changes in extracellular [Ca(2+)] and promotes Ca(2+) influx and intracellular Ca(2+) release. The CaSR is broadly expressed in the CNS and colocalized with the inhibitory γ-aminobutyric acid-B receptor 1 (GABA-B-R1). In hippocampal neurons, GABA-B-R1 heterodimerizes with CaSR and suppresses CaSR expression. To study the interplay between these two receptors in the development of ischemic cell death and neuroprotection by hypothermia, we subjected C57/BL6 mice to global cerebral ischemia by performing bilateral carotid artery occlusion (10 min) followed by reperfusion for 1-3 days with or without therapeutic hypothermia (33°C for 3 h at the onset of reperfusion). Terminal deoxynucleotidyl transferase dUTP nick end labeling staining and immunohistochemistry showed that forebrain ischemia increased CaSR expression, decreased GABA-B-R1 expression, and promoted cell death. These changes were particularly evident in hippocampal neurons and could be reversed by mild hypothermia. The induction of CaSR, along with reciprocal decreases in GABA-B-R1 expression, may together potentiate ischemic neuronal death, suggesting a new therapeutic target for treatment of ischemic brain injury.
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Ostwald SK, Godwin KM, Ye F, Cron SG. Serious adverse events experienced by survivors of stroke in the first year following discharge from inpatient rehabilitation. Rehabil Nurs 2013; 38:254-63. [PMID: 23686536 PMCID: PMC3751976 DOI: 10.1002/rnj.87] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2012] [Indexed: 01/09/2023]
Abstract
PURPOSE To identify the incidence of adverse events (AE) that occurred in stroke survivors during the first year following discharge from inpatient rehabilitation and to determine the type and patterns of AE. METHODS Data were collected for 12 months on events resulting in admissions to the emergency department, hospital, long-term care facility, or death. Descriptive statistics were used to depict the patterns of AE and univariate comparisons were made of the differences between survivors who did or did not experience one or more AE. RESULTS Of the 159 participants, 50% reported a total of 163 AE. Most AE (82.2%) were unexpected and the majority occurred during the first 6 months; 12 recurrent strokes and 6 transient ischemic attacks occcurred. CONCLUSIONS Education on prevention and treatment of common AE is important prior to discharge. Anticipatory guidance may help survivors and caregivers modify their lifestyle and prevent common AE.
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Affiliation(s)
- Sharon K Ostwald
- Center on Aging, School of Nursing, University of Texas Health Science Center at Houston, Houston, TX, USA.
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The activity within the CA3 excitatory network during Theiler's virus encephalitis is distinct from that observed during chronic epilepsy. J Neurovirol 2012; 18:30-44. [PMID: 22328242 DOI: 10.1007/s13365-012-0082-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 11/29/2011] [Indexed: 02/02/2023]
Abstract
Viral infections of the central nervous system (CNS) are associated with an increased risk for seizures during the acute infection period and the subsequent development of chronic epilepsy that is often difficult to treat. In previous work, we have shown that mice of the C57BL/6 strain infected with Theiler's murine encephalomyelitis virus (TMEV) exhibit a similar sequence, thereby providing a potential useful model of virus-induced epilepsy. The present study examines spontaneous and miniature excitatory postsynaptic currents in CA3 pyramidal cells recorded from brain slices prepared during both the acute phase during encephalitis and 2 months following TMEV infection. Animals that develop chronic epilepsy following TMEV infection exhibit considerable hippocampal sclerosis, directly implicating this brain region in the process of epileptogenesis. There are significant increases in amplitude and frequency of spontaneous and miniature excitatory currents in CA3 cells recorded in brain slices prepared during the acute infection period and 2 months after infection. However, the patterns of changes observed are markedly different during these two periods, suggesting that there are underlying changes in the network over time. These differences have implications for the treatment used during the acute infection and after chronic seizures develop.
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Experimental models of seizures and epilepsies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 105:57-82. [PMID: 22137429 DOI: 10.1016/b978-0-12-394596-9.00003-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epilepsy is one of the most common neurological conditions that affect people of all ages. Epilepsy is characterized by occurrence of spontaneous recurrent seizures. Currently available drugs are ineffective in controlling seizures in approximately one-third of patients with epilepsy. Moreover, these drugs are associated with adverse effects, and none of them are effective in preventing development of epilepsy following an insult or injury. To develop an effective therapeutic strategy that can interfere with the process of development of epilepsy (epileptogenesis), it is crucial to study the changes that occur in the brain after an injury and before epilepsy develops. It is not possible to determine these changes in human tissue for obvious ethical reasons. Over the years, experimental models of epilepsies have contributed immensely in improving our understanding of mechanism of epileptogenesis as well as of seizure generation. There are many models that replicate at least some of the characteristics of human epilepsy. Each model has its advantages and disadvantages, and the investigator should be aware of this before selecting a specific model for his/her studies. Availability of a good animal model is a key to the development of an effective treatment. Unfortunately, there are many epilepsy syndromes, specifically pediatric, which still lack a valid animal model. It is vital that more research is done to develop animal models for such syndromes.
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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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Curia G, Levitt M, Fender JS, Miller JW, Ojemann J, D'Ambrosio R. Impact of injury location and severity on posttraumatic epilepsy in the rat: role of frontal neocortex. Cereb Cortex 2010; 21:1574-92. [PMID: 21112931 DOI: 10.1093/cercor/bhq218] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Human posttraumatic epilepsy (PTE) is highly heterogeneous, ranging from mild remitting to progressive disabling forms. PTE results in simple partial, complex partial, and secondarily generalized seizures with a wide spectrum of durations and semiologies. PTE variability is thought to depend on the heterogeneity of head injury and patient's age, gender, and genetic background. To better understand the role of these factors, we investigated the seizures resulting from calibrated fluid percussion injury (FPI) to adolescent male Sprague-Dawley rats with video electrocorticography. We show that PTE incidence and the frequency and severity of chronic seizures depend on the location and severity of FPI. The frontal neocortex was more prone to epileptogenesis than the parietal and occipital, generating earlier, longer, and more frequent partial seizures. A prominent limbic focus developed in most animals, regardless of parameters of injury. Remarkably, even with carefully controlled injury parameters, including type, severity, and location, the duration of posttraumatic apnea and the age and gender of outbred rats, there was great subject-to-subject variability in frequency, duration, and rate of progression of seizures, indicating that other factors, likely the subjects' genetic background and physiological states, have critical roles in determining the characteristics of PTE.
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Affiliation(s)
- Giulia Curia
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, 41100 Modena, Italy
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Goulton CS, Patten AR, Kerr JR, Kerr DS. Pharmacological Preconditioning with GYKI 52466: A Prophylactic Approach to Neuroprotection. Front Neurosci 2010; 4. [PMID: 20953290 PMCID: PMC2955399 DOI: 10.3389/fnins.2010.00054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 07/02/2010] [Indexed: 11/13/2022] Open
Abstract
Some toxins and drugs can trigger lasting neuroprotective mechanisms that enable neurons to resist a subsequent severe insult. This “pharmacological preconditioning” has far-reaching implications for conditions in which blood flow to the brain is interrupted. We have previously shown that in vitro preconditioning with the AMPA receptor antagonist GYKI 52466 induces tolerance to kainic acid (KA) toxicity in hippocampus. This effect persists well after washout of the drug and may be mediated via inverse agonism of G-protein coupled receptors (GPCRs). Given the amplifying nature of metabotropic modulation, we hypothesized that GYKI 52466 may be effective in reducing seizure severity at doses well below those normally associated with adverse side effects. Here we report that pharmacological preconditioning with low-dose GYKI imparts a significant protection against KA-induced seizures in vivo. GYKI (3 mg/kg, s.c.), 90–180 min prior to high-dose KA, markedly reduced seizure scores, virtually abolished all level 3 and level 4 seizures, and completely suppressed KA-induced hippocampal c-FOS expression. In addition, preconditioned animals exhibited significant reductions in high frequency/high amplitude spiking and ECoG power in the delta, theta, alpha, and beta bands during KA. Adverse behaviors often associated with higher doses of GYKI were not evident during preconditioning. The fact that GYKI is effective at doses well-below, and at pre-administration intervals well-beyond previous studies, suggests that a classical blockade of ionotropic AMPA receptors does not underlie anticonvulsant effects. Low-dose GYKI preconditioning may represent a novel, prophylactic strategy for neuroprotection in a field almost completely devoid of effective pharmaceuticals.
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Affiliation(s)
- Chelsea S Goulton
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Dunedin, New Zealand
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Samoilova M, Weisspapir M, Abdelmalik P, Velumian AA, Carlen PL. Chronicin vitroketosis is neuroprotective but not anti-convulsant. J Neurochem 2010; 113:826-35. [DOI: 10.1111/j.1471-4159.2010.06645.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Transient and Spontaneously-Remitting Complex Hallucinations in a Patient With Melanoma and Brain Metastases. PSYCHOSOMATICS 2010. [DOI: 10.1016/s0033-3182(10)70694-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
Epileptogenesis is defined as the process of developing epilepsy-a disorder characterized by recurrent seizures-following an initial insult. Seizure incidence during the human lifespan is at its highest in infancy and childhood. Animal models of epilepsy and human tissue studies suggest that epileptogenesis involves a cascade of molecular, cellular and neuronal network alterations. Within minutes to days following the initial insult, there are acute early changes in neuronal networks, which include rapid alterations to ion channel kinetics as a result of membrane depolarization, post-translational modifications to existing functional proteins, and activation of immediate early genes. Subacute changes occur over hours to weeks, and include transcriptional events, neuronal death and activation of inflammatory cascades. The chronic changes that follow over weeks to months include anatomical changes, such as neurogenesis, mossy fiber sprouting, network reorganization, and gliosis. These epileptogenic processes are developmentally regulated and might contribute to differences in epileptogenesis between adult and developing brains. Here we review the factors responsible for enhanced seizure susceptibility in the developing brain, and consider age-specific mechanisms of epileptogenesis. An understanding of these factors could yield potential therapeutic targets for the prevention of epileptogenesis and also provide biomarkers for identifying patients at risk of developing epilepsy or for monitoring disease progression.
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