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Junghans K, Wyeth M, Buckmaster PS. Rat strain differences in seizure frequency and hilar neuron loss after systemic treatment with pilocarpine. Epilepsy Res 2024; 204:107384. [PMID: 38879905 PMCID: PMC11253724 DOI: 10.1016/j.eplepsyres.2024.107384] [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: 02/13/2024] [Revised: 05/13/2024] [Accepted: 05/29/2024] [Indexed: 06/18/2024]
Abstract
At least 3 months after systemic treatment with pilocarpine to induce status epilepticus, Long-Evans and Sprague-Dawley rats were video-EEG monitored for seizures continuously for 1 month. Rats were then perfused, hippocampi were processed for Nissl staining, and hilar neurons were quantified. Seizure frequency in Long-Evans rats was 1/10th of that in Sprague-Dawley rats, and more variable. Hilar neuron loss was also less severe in Long-Evans rats. However, there was no correlation between hilar neuron loss and seizure frequency in either strain. The low and variable seizure frequency suggests limited usefulness of pilocarpine-treated Long-Evans rats for some epilepsy experiments.
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Affiliation(s)
- Kristina Junghans
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA
| | - Megan Wyeth
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA.
| | - Paul S Buckmaster
- Departments of Comparative Medicine, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA; Departments of Neurology & Neurological Sciences, Stanford University, 3172 Porter Drive, Palo Alto, CA 94304-5475, USA
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2
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Lévesque M, Biagini G, de Curtis M, Gnatkovsky V, Pitsch J, Wang S, Avoli M. The pilocarpine model of mesial temporal lobe epilepsy: Over one decade later, with more rodent species and new investigative approaches. Neurosci Biobehav Rev 2021; 130:274-291. [PMID: 34437936 DOI: 10.1016/j.neubiorev.2021.08.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/17/2021] [Accepted: 08/21/2021] [Indexed: 01/19/2023]
Abstract
Fundamental work on the mechanisms leading to focal epileptic discharges in mesial temporal lobe epilepsy (MTLE) often rests on the use of rodent models in which an initial status epilepticus (SE) is induced by kainic acid or pilocarpine. In 2008 we reviewed how, following systemic injection of pilocarpine, the main subsequent events are the initial SE, the latent period, and the chronic epileptic state. Up to a decade ago, rats were most often employed and they were frequently analysed only behaviorally. However, the use of transgenic mice has revealed novel information regarding this animal model. Here, we review recent findings showing the existence of specific neuronal events during both latent and chronic states, and how optogenetic activation of specific cell populations modulate spontaneous seizures. We also address neuronal damage induced by pilocarpine treatment, the role of neuroinflammation, and the influence of circadian and estrous cycles. Updating these findings leads us to propose that the rodent pilocarpine model continues to represent a valuable tool for identifying the basic pathophysiology of MTLE.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Giuseppe Biagini
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena & Reggio Emilia, 41100 Modena, Italy
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milano, Italy; Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Julika Pitsch
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Siyan Wang
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montreal, QC, H3A 2B4, Canada; Departments of Physiology, McGill University, Montreal, QC, H3A 2B4, Canada; Department of Experimental Medicine, Sapienza University of Rome, 00185 Roma, Italy.
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3
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Chauvière L. Update on temporal lobe‐dependent information processing, in health and disease. Eur J Neurosci 2019; 51:2159-2204. [DOI: 10.1111/ejn.14594] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/06/2019] [Accepted: 09/27/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Laëtitia Chauvière
- INSERM U1266 Institut de Psychiatrie et de Neurosciences de Paris (IPNP) Paris France
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4
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Santos VR, Kobayashi I, Hammack R, Danko G, Forcelli PA. Impact of strain, sex, and estrous cycle on gamma butyrolactone-evoked absence seizures in rats. Epilepsy Res 2018; 147:62-70. [PMID: 30261353 PMCID: PMC6226012 DOI: 10.1016/j.eplepsyres.2018.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/03/2018] [Accepted: 09/15/2018] [Indexed: 12/19/2022]
Abstract
Childhood absence epilepsy (CAE) is the most common pediatric epilepsy syndrome and is characterized by typical absence seizures (AS). AS are non-convulsive epileptic seizures characterized by a sudden loss of awareness and bilaterally generalized synchronous 2.5-4 Hz spike and slow-wave discharges (SWD). Gamma butyrolactone (GBL) is an acute pharmacological model of AS and induces bilaterally synchronous SWDs and behavioral arrest. Despite the long use of this model, little is known about its strain and sex-dependent features. We compared the dose-response profile of GBL-evoked SWDs in three rat strains (Long Evans, Sprague-Dawley, and Wistar), and examined the modulatory effects of estrous cycle on SWDs in female Wistar rats. We evaluated the number of seizures, the cumulative time seizing, and the average seizure duration as a function of dose, strain, and sex/estrous phase. Long Evans rats displayed the greatest sensitivity to GBL, followed by Wistar rats, and then by Sprague-Dawley rats. GBL-evoked SWDs were modulated by estrous cycle in female rats, with the lowest sensitivity to GBL occurring during metestrus. Wistar rats showed the greatest variability as a function of dose, and the least variability within dose; these features make this strain desirable for interventional studies. Moreover, our finding that the SWD response to GBL differs as a function of estrous cycle underscores the importance of cycle monitoring in studies examining female animals using this model. Together, these strain and sex-dependent findings provide guidance for future studies.
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Affiliation(s)
- Victor R Santos
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Ihori Kobayashi
- Department of Psychiatry and Behavioral Sciences, Howard University College of Medicine, United States
| | - Robert Hammack
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Gregory Danko
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University School of Medicine, United States; Department of Neuroscience, Georgetown University School of Medicine, United States; Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, United States.
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5
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Keeley RJ, Bye C, Trow J, McDonald RJ. Adolescent THC exposure does not sensitize conditioned place preferences to subthreshold d-amphetamine in male and female rats. F1000Res 2018; 7:342. [PMID: 29770212 PMCID: PMC5920568 DOI: 10.12688/f1000research.14029.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/11/2018] [Indexed: 12/18/2022] Open
Abstract
The acute effects of marijuana consumption on brain physiology and behaviour are well documented, but the long-term effects of its chronic use are less well known. Chronic marijuana use during adolescence is of increased interest, given that the majority of individuals first use marijuana during this developmental stage , and adolescent marijuana use is thought to increase the susceptibility to abusing other drugs when exposed later in life. It is possible that marijuana use during critical periods in adolescence could lead to increased sensitivity to other drugs of abuse later on. To test this, we chronically administered ∆ 9-tetrahydrocannabinol (THC) to male and female Long-Evans (LER) and Wistar (WR) rats directly after puberty onset. Rats matured to postnatal day 90 before being exposed to a conditioned place preference task (CPP). A subthreshold dose of d-amphetamine, found not to induce place preference in drug naïve rats, was used as the unconditioned stimulus. The effect of d-amphetamine on neural activity was inferred by quantifying cfos expression in the nucleus accumbens and dorsal hippocampus following CPP training. Chronic exposure to THC post-puberty had no potentiating effect on a subthreshold dose of d-amphetamine to induce CPP. No differences in cfos expression were observed. These results show that chronic exposure to THC during puberty did not increase sensitivity to a sub-threshold dose of d-amphetamine in adult LER and WR rats. This supports the concept that THC may not sensitize the response to all drugs of abuse.
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Affiliation(s)
- Robin J Keeley
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
- National Institute on Drug Abuse, 251 Bayview blvd, Suite 200, Baltimore, MD, 21224, USA
| | - Cameron Bye
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
| | - Jan Trow
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
| | - Robert J McDonald
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
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Keeley RJ, Bye C, Trow J, McDonald RJ. Adolescent THC exposure does not sensitize conditioned place preferences to subthreshold d-amphetamine in male and female rats. F1000Res 2018; 7:342. [PMID: 29770212 PMCID: PMC5920568 DOI: 10.12688/f1000research.14029.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/02/2018] [Indexed: 09/29/2023] Open
Abstract
The acute effects of marijuana consumption on brain physiology and behaviour are well documented, but the long-term effects of its chronic use are less well known. Chronic marijuana use during adolescence is of increased interest, given that the majority of individuals first use marijuana during this developmental stage , and adolescent marijuana use is thought to increase the susceptibility to abusing other drugs when exposed later in life. It is possible that marijuana use during critical periods in adolescence could lead to increased sensitivity to other drugs of abuse later on. To test this, we chronically administered ∆ 9-tetrahydrocannabinol (THC) to male and female Long-Evans (LER) and Wistar (WR) rats directly after puberty onset. Rats matured to postnatal day 90 before being exposed to a conditioned place preference task (CPP). A subthreshold dose of d-amphetamine, found not to induce place preference in drug naïve rats, was used as the unconditioned stimulus. The effect of d-amphetamine on neural activity was inferred by quantifying cfos expression in the nucleus accumbens and dorsal hippocampus following CPP training. Chronic exposure to THC post-puberty had no potentiating effect on a subthreshold dose of d-amphetamine to induce CPP. No differences in cfos expression were observed. These results show that chronic exposure to THC during puberty did not increase sensitivity to d-amphetamine in adult LER and WR rats. This supports the concept that THC may not sensitize the response to all drugs of abuse.
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Affiliation(s)
- Robin J Keeley
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
- National Institute on Drug Abuse, 251 Bayview blvd, Suite 200, Baltimore, MD, 21224, USA
| | - Cameron Bye
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
| | - Jan Trow
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
| | - Robert J McDonald
- University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada
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7
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Bertoglio D, Amhaoul H, Van Eetveldt A, Houbrechts R, Van De Vijver S, Ali I, Dedeurwaerdere S. Kainic Acid-Induced Post-Status Epilepticus Models of Temporal Lobe Epilepsy with Diverging Seizure Phenotype and Neuropathology. Front Neurol 2017; 8:588. [PMID: 29163349 PMCID: PMC5681498 DOI: 10.3389/fneur.2017.00588] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/20/2017] [Indexed: 12/28/2022] Open
Abstract
The aim of epilepsy models is to investigate disease ontogenesis and therapeutic interventions in a consistent and prospective manner. The kainic acid-induced status epilepticus (KASE) rat model is a widely used, well-validated model for temporal lobe epilepsy (TLE). As we noted significant variability within the model between labs potentially related to the rat strain used, we aimed to describe two variants of this model with diverging seizure phenotype and neuropathology. In addition, we evaluated two different protocols to induce status epilepticus (SE). Wistar Han (Charles River, France) and Sprague-Dawley (Harlan, The Netherlands) rats were subjected to KASE using the Hellier kainic acid (KA) and a modified injection scheme. Duration of SE and latent phase were characterized by video-electroencephalography (vEEG) in a subgroup of animals, while animals were sacrificed 1 week (subacute phase) and 12 weeks (chronic phase) post-SE. In the 12 weeks post-SE groups, seizures were monitored with vEEG. Neuronal loss (neuronal nuclei), microglial activation (OX-42 and translocator protein), and neurodegeneration (Fluorojade C) were assessed. First, the Hellier protocol caused very high mortality in WH/CR rats compared to SD/H animals. The modified protocol resulted in a similar SE severity for WH/CR and SD/H rats, but effectively improved survival rates. The latent phase was significantly shorter (p < 0.0001) in SD/H (median 8.3 days) animals compared to WH/CR (median 15.4 days). During the chronic phase, SD/H rats had more seizures/day compared to WH/CR animals (p < 0.01). However, neuronal degeneration and cell loss were overall more extensive in WH/CR than in SD/H rats; microglia activation was similar between the two strains 1 week post-SE, but higher in WH/CR rats 12 weeks post-SE. These neuropathological differences may be more related to the distinct neurotoxic effects of KA in the two rat strains than being the outcome of seizure burden itself. The divergences in disease progression and seizure outcome, in addition to the histopathological dissimilarities, further substantiate the existence of strain differences for the KASE rat model of TLE.
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Affiliation(s)
- Daniele Bertoglio
- Department of Translational Neurosciences, University of Antwerp, Antwerp, Belgium
| | - Halima Amhaoul
- Department of Translational Neurosciences, University of Antwerp, Antwerp, Belgium
| | - Annemie Van Eetveldt
- Department of Translational Neurosciences, University of Antwerp, Antwerp, Belgium
| | - Ruben Houbrechts
- Department of Translational Neurosciences, University of Antwerp, Antwerp, Belgium
| | | | - Idrish Ali
- Department of Translational Neurosciences, University of Antwerp, Antwerp, Belgium
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8
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Löscher W, Ferland RJ, Ferraro TN. The relevance of inter- and intrastrain differences in mice and rats and their implications for models of seizures and epilepsy. Epilepsy Behav 2017; 73. [PMID: 28651171 PMCID: PMC5909069 DOI: 10.1016/j.yebeh.2017.05.040] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
It is becoming increasingly clear that the genetic background of mice and rats, even in inbred strains, can have a profound influence on measures of seizure susceptibility and epilepsy. These differences can be capitalized upon through genetic mapping studies to reveal genes important for seizures and epilepsy. However, strain background and particularly mixed genetic backgrounds of transgenic animals need careful consideration in both the selection of strains and in the interpretation of results and conclusions. For instance, mice with targeted deletions of genes involved in epilepsy can have profoundly disparate phenotypes depending on the background strain. In this review, we discuss findings related to how this genetic heterogeneity has and can be utilized in the epilepsy field to reveal novel insights into seizures and epilepsy. Moreover, we discuss how caution is needed in regards to rodent strain or even animal vendor choice, and how this can significantly influence seizure and epilepsy parameters in unexpected ways. This is particularly critical in decisions regarding the strain of choice used in generating mice with targeted deletions of genes. Finally, we discuss the role of environment (at vendor and/or laboratory) and epigenetic factors for inter- and intrastrain differences and how such differences can affect the expression of seizures and the animals' performance in behavioral tests that often accompany acute and chronic seizure testing.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| | - Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurology, Albany Medical College, Albany, NY, United States
| | - Thomas N Ferraro
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, United States
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9
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Vezzani A, Pascente R, Ravizza T. Biomarkers of Epileptogenesis: The Focus on Glia and Cognitive Dysfunctions. Neurochem Res 2017; 42:2089-2098. [PMID: 28434163 DOI: 10.1007/s11064-017-2271-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/12/2017] [Accepted: 04/17/2017] [Indexed: 12/31/2022]
Abstract
The need to find measures that reliably predict the onset of epilepsy after injurious events or how the patient will respond to anti-seizure drugs led to intensive pre-clinical and clinical research to discover non-invasive biomarkers that could increase the sensitivity of existing clinical indicators. The use of experimental models of epileptogenesis and of drug-resistance is instrumental to select the most promising approaches to explore such biomarkers in the pre-clinical setting for further clinical validation. The approaches most frequently used to find clinically useful biomarkers of epileptogenesis include molecular brain imaging, EEG signal analysis and the measure of soluble molecules in biofluids which may reflect brain intrinsic events involved in epilepsy development. Among those, we focused our attention on proton magnetic resonance imaging (1H-MRS)-based analysis of astrocytic activation, and related blood biomarkers, since this cell population appears to be pivotally involved in various epileptogenesis processes triggered by differing insults. Moreover, we also investigated behavioral biomarkers by focusing on cognitive dysfunctions since this deficit represents a typical co-morbidity in epilepsy which may manifest even before the onset of spontaneous seizures. In this review article, we will report our recently published evidence supporting the utility of measuring astrocyte activation, the soluble molecules they release, and the associated cognitive deficits during epileptogenesis for early stratification of animals developing epilepsy. We will discuss the potential clinical translation of our findings for enriching the patient population in preventive clinical trials designed to study anti-epileptogenic treatments.
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Affiliation(s)
- Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto Di Ricerche Farmacologiche Mario Negri, Via G. La Masa, 19, 20156, Milan, Italy.
| | - Rosaria Pascente
- Department of Neuroscience, IRCCS-Istituto Di Ricerche Farmacologiche Mario Negri, Via G. La Masa, 19, 20156, Milan, Italy
| | - Teresa Ravizza
- Department of Neuroscience, IRCCS-Istituto Di Ricerche Farmacologiche Mario Negri, Via G. La Masa, 19, 20156, Milan, Italy
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Ravizza T, Onat FY, Brooks-Kayal AR, Depaulis A, Galanopoulou AS, Mazarati A, Numis AL, Sankar R, Friedman A. WONOEP appraisal: Biomarkers of epilepsy-associated comorbidities. Epilepsia 2016; 58:331-342. [PMID: 28035782 DOI: 10.1111/epi.13652] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2016] [Indexed: 01/04/2023]
Abstract
Neurologic and psychiatric comorbidities are common in patients with epilepsy. Diagnostic, predictive, and pharmacodynamic biomarkers of such comorbidities do not exist. They may share pathogenetic mechanisms with epileptogenesis/ictogenesis, and as such are an unmet clinical need. The objectives of the subgroup on biomarkers of comorbidities at the XIII Workshop on the Neurobiology of Epilepsy (WONOEP) were to present the state-of-the-art recent research findings in the field that highlighting potential biomarkers for comorbidities in epilepsy. We review recent progress in the field, including molecular, imaging, and genetic biomarkers of comorbidities as discussed during the WONOEP meeting on August 31-September 4, 2015, in Heybeliada Island (Istanbul, Turkey). We further highlight new directions and concepts from studies on comorbidities and potential new biomarkers for the prediction, diagnosis, and treatment of epilepsy-associated comorbidities. The activation of various molecular signaling pathways such as the "Janus Kinase/Signal Transducer and Activator of Transcription," "mammalian Target of Rapamycin," and oxidative stress have been shown to correlate with the presence and severity of subsequent cognitive abnormalities. Furthermore, dysfunction in serotonergic transmission, hyperactivity of the hypothalamic-pituitary-adrenocortical axis, the role of the inflammatory cytokines, and the contributions of genetic factors have all recently been regarded as relevant for understanding epilepsy-associated depression and cognitive deficits. Recent evidence supports the utility of imaging studies as potential biomarkers. The role of such biomarker may be far beyond the diagnosis of comorbidities, as accumulating clinical data indicate that comorbidities can predict epilepsy outcomes. Future research is required to reveal whether molecular changes in specific signaling pathways or advanced imaging techniques could be detected in the clinical settings and correlate with epilepsy-associated comorbidities. A reliable biomarker will allow a more accurate diagnosis and improved treatment of epilepsy-associated comorbidities.
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Affiliation(s)
- Teresa Ravizza
- Department of Neuroscience, IRCCS-"Mario Negri" Institute for Pharmacological Research, Milano, Italy
| | - Filiz Y Onat
- Department of Medical Pharmacology, Epilepsy Research Center, School of Medicine Marmara University, Istanbul, Turkey
| | - Amy R Brooks-Kayal
- Department of Pediatrics, Neurology and Pharmaceutical Sciences, Children's Hospital Colorado, University of Colorado Schools of Medicine and Pharmacy, Aurora, Colorado, U.S.A
| | | | - Aristea S Galanopoulou
- Laboratory of Developmental Neuroscience, Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, U.S.A.,Montefiore/Einstein Comprehensive Epilepsy Center, Montefiore Medical Center, Bronx, New York, U.S.A
| | - Andrey Mazarati
- Neurology Division, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Adam L Numis
- Neurology Division, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Raman Sankar
- Neurology Division, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A
| | - Alon Friedman
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Medical Neuroscience, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
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11
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Sadeghi L, Rizvanov AA, Salafutdinov II, Dabirmanesh B, Sayyah M, Fathollahi Y, Khajeh K. Hippocampal asymmetry: differences in the left and right hippocampus proteome in the rat model of temporal lobe epilepsy. J Proteomics 2016; 154:22-29. [PMID: 27932302 DOI: 10.1016/j.jprot.2016.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/24/2016] [Accepted: 11/30/2016] [Indexed: 01/08/2023]
Abstract
The hippocampus is a complex brain structure and undergoes severe sclerosis and gliosis in temporal lobe epilepsy (TLE) as the most common type of epilepsy. The key features of the TLE may be reported in chronic animal models of epilepsy, such as pilocarpine model. Therefore, the current study was conducted in a rat pilocarpine model of acquired epilepsy. Two-dimensional gel electrophoresis based proteomic technique was used to compare the proteome map of the left and right hippocampus in both control and epileptic rats. Generally, 95 differentially expressed spots out of 1300 spots were identified in the hippocampus proteome using MALDI-TOF-TOF/MS. Within identified proteins, some showed asymmetric expression related to the mechanisms underlying TLE imposed by pilocarpine. Assessment of lateralization at the molecular level demonstrated that expression of proteins involved in dopamine synthesis was significantly more in the right hippocampus than the left one. In the epileptic model, reduction in dopamine pathway proteins was accompanied by an increase in the expression of proteins involved in polyamine synthesis, referring to a new regulating mechanism. Our results revealed changes in the laterality of protein expression due to pilocarpine-induced status epilepticus that could present some new proteins as potential candidates for antiepileptic drug design. BIOLOGICAL SIGNIFICANCE In the current study, two-dimensional gel electrophoresis (2-DE) based proteomic technique was used to profile changes in the left and right hippocampus proteome after pilocarpine induced status epilepticus. Spots of proteome maps for two hemispheres were excised and identified with MALDI-TOF-TOF/MS. Analysis of proteome map of the left and right hippocampus revealed a lateralization at the molecular level, in which the expression of proteins involved in dopamine synthesis and release were significantly more in right hippocampi than the left ones in the normal rats. Also, the expression of proteins involved in polyamine synthesis significantly increased in epileptic hippocampus (considerably higher in right hippocampi), whilst the proteins which included in dopamine pathways were decreased. Our results revealed changes in the laterality of protein expression due to pilocarpine-induced status epilepticus that could present some new proteins as potential candidates for antiepileptic drug design.
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Affiliation(s)
- Leila Sadeghi
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran
| | | | | | - Bahareh Dabirmanesh
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Sayyah
- Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran
| | - Yaghoub Fathollahi
- Department of Medical Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Khosro Khajeh
- Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran.
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Terrone G, Pauletti A, Pascente R, Vezzani A. Preventing epileptogenesis: A realistic goal? Pharmacol Res 2016; 110:96-100. [DOI: 10.1016/j.phrs.2016.05.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 12/16/2022]
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13
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Pascente R, Frigerio F, Rizzi M, Porcu L, Boido M, Davids J, Zaben M, Tolomeo D, Filibian M, Gray WP, Vezzani A, Ravizza T. Cognitive deficits and brain myo-Inositol are early biomarkers of epileptogenesis in a rat model of epilepsy. Neurobiol Dis 2016; 93:146-55. [PMID: 27173096 DOI: 10.1016/j.nbd.2016.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 04/26/2016] [Accepted: 05/05/2016] [Indexed: 10/21/2022] Open
Abstract
One major unmet clinical need in epilepsy is the identification of therapies to prevent or arrest epilepsy development in patients exposed to a potential epileptogenic insult. The development of such treatments has been hampered by the lack of non-invasive biomarkers that could be used to identify the patients at-risk, thereby allowing to design affordable clinical studies. Our goal was to test the predictive value of cognitive deficits and brain astrocyte activation for the development of epilepsy following a potential epileptogenic injury. We used a model of epilepsy induced by pilocarpine-evoked status epilepticus (SE) in 21-day old rats where 60-70% of animals develop spontaneous seizures after around 70days, although SE is similar in all rats. Learning was evaluated in the Morris water-maze at days 15 and 65 post-SE, each time followed by proton magnetic resonance spectroscopy for measuring hippocampal myo-Inositol levels, a marker of astrocyte activation. Rats were video-EEG monitored for two weeks at seven months post-SE to detect spontaneous seizures, then brain histology was done. Behavioral and imaging data were retrospectively analysed in epileptic rats and compared with non-epileptic and control animals. Rats displayed spatial learning deficits within three weeks from SE. However, only epilepsy-prone rats showed accelerated forgetting and reduced learning rate compared to both rats not developing epilepsy and controls. These deficits were associated with reduced hippocampal neurogenesis. myo-Inositol levels increased transiently in the hippocampus of SE-rats not developing epilepsy while this increase persisted until spontaneous seizures onset in epilepsy-prone rats, being associated with a local increase in S100β-positive astrocytes. Neuronal cell loss was similar in all SE-rats. Our data show that behavioral deficits, together with a non-invasive marker of astrocyte activation, predict which rats develop epilepsy after an acute injury. These measures have potential clinical relevance for identifying individuals at-risk for developing epilepsy following exposure to epileptogenic insults, and consequently, for designing adequately powered antiepileptogenesis trials.
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Affiliation(s)
- Rosaria Pascente
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Federica Frigerio
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Massimo Rizzi
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Luca Porcu
- Department of Oncology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Marina Boido
- Neuroscience Institute "Cavalieri Ottolenghi", Department of Neuroscience, University of Torino, Torino, Italy
| | - Joe Davids
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | - Malik Zaben
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | - Daniele Tolomeo
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Marta Filibian
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - William P Gray
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Teresa Ravizza
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy.
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Maia GH, Quesado JL, Soares JI, do Carmo JM, Andrade PA, Andrade JP, Lukoyanov NV. Loss of hippocampal neurons after kainate treatment correlates with behavioral deficits. PLoS One 2014; 9:e84722. [PMID: 24409306 PMCID: PMC3883667 DOI: 10.1371/journal.pone.0084722] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 11/18/2013] [Indexed: 11/18/2022] Open
Abstract
Treating rats with kainic acid induces status epilepticus (SE) and leads to the development of behavioral deficits and spontaneous recurrent seizures later in life. However, in a subset of rats, kainic acid treatment does not induce overt behaviorally obvious acute SE. The goal of this study was to compare the neuroanatomical and behavioral changes induced by kainate in rats that developed convulsive SE to those who did not. Adult male Wistar rats were treated with kainic acid and tested behaviorally 5 months later. Rats that had experienced convulsive SE showed impaired performance on the spatial water maze and passive avoidance tasks, and on the context and tone retention tests following fear conditioning. In addition, they exhibited less anxiety-like behaviors than controls on the open-field and elevated plus-maze tests. Histologically, convulsive SE was associated with marked neuron loss in the hippocampal CA3 and CA1 fields, and in the dentate hilus. Rats that had not experienced convulsive SE after kainate treatment showed less severe, but significant impairments on the spatial water maze and passive avoidance tasks. These rats had fewer neurons than control rats in the dentate hilus, but not in the hippocampal CA3 and CA1 fields. Correlational analyses revealed significant relationships between spatial memory indices of rats and neuronal numbers in the dentate hilus and CA3 pyramidal field. These results show that a part of the animals that do not display intense behavioral seizures (convulsive SE) immediately after an epileptogenic treatment, later in life, they may still have noticeable structural and functional changes in the brain.
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Affiliation(s)
- Gisela H. Maia
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- Neural Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - José L. Quesado
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Joana I. Soares
- Neural Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Joana M. do Carmo
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - Pedro A. Andrade
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
| | - José P. Andrade
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Nikolai V. Lukoyanov
- Departamento de Anatomia, Faculdade de Medicina da Universidade do Porto, Porto, Portugal
- Neural Networks Group, Instituto de Biologia Molecular e Celular da Universidade do Porto, Porto, Portugal
- Programa Doutoral em Neurociências, Universidade do Porto, Porto, Portugal
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Cognitive and behavioral comorbidities in epilepsy: the treacherous nature of animal models. Epilepsy Curr 2013; 13:182-3. [PMID: 24009484 DOI: 10.5698/1535-7597-13.4.182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Brooks-Kayal AR, Bath KG, Berg AT, Galanopoulou AS, Holmes GL, Jensen FE, Kanner AM, O'Brien TJ, Whittemore VH, Winawer MR, Patel M, Scharfman HE. Issues related to symptomatic and disease-modifying treatments affecting cognitive and neuropsychiatric comorbidities of epilepsy. Epilepsia 2013; 54 Suppl 4:44-60. [PMID: 23909853 PMCID: PMC3924317 DOI: 10.1111/epi.12298] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Many symptoms of neurologic or psychiatric illness--such as cognitive impairment, depression, anxiety, attention deficits, and migraine--occur more frequently in people with epilepsy than in the general population. These diverse comorbidities present an underappreciated problem for people with epilepsy and their caregivers because they decrease quality of life, complicate treatment, and increase mortality. In fact, it has been suggested that comorbidities can have a greater effect on quality of life in people with epilepsy than the seizures themselves. There is increasing recognition of the frequency and impact of cognitive and behavioral comorbidities of epilepsy, highlighted in the 2012 Institute of Medicine report on epilepsy. Comorbidities have also been acknowledged, as a National Institutes of Health (NIH) Benchmark area for research in epilepsy. However, relatively little progress has been made in developing new therapies directed specifically at comorbidities. On the other hand, there have been many advances in understanding underlying mechanisms. These advances have made it possible to identify novel targets for therapy and prevention. As part of the International League Against Epilepsy/American Epilepsy Society workshop on preclinical therapy development for epilepsy, our working group considered the current state of understanding related to terminology, models, and strategies for therapy development for the comorbidities of epilepsy. Herein we summarize our findings and suggest ways to accelerate development of new therapies. We also consider important issues to improve research including those related to methodology, nonpharmacologic therapies, biomarkers, and infrastructure.
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Affiliation(s)
- Amy R Brooks-Kayal
- Departments of Pediatrics, Neurology and Pharmaceutical Sciences, University of Colorado Schools of Medicine and Pharmacy, Children's Hospital Colorado, Aurora, Colorado, USA.
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Trichosanthes tricuspidata modulates oxidative toxicity in brain hippocampus against pilocarpine induced status epilepticus in mice. Neurochem Res 2013; 38:1715-25. [PMID: 23686347 DOI: 10.1007/s11064-013-1075-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/06/2013] [Accepted: 05/09/2013] [Indexed: 10/26/2022]
Abstract
Epilepsy prevails to be a neurological disorder in anticipation of safer drugs with enhanced anticonvulsant efficacy as presently available drugs fails to offer adequate control of epileptic seizures in about one-third of patients. The objective of this study was to evaluate the effect of Trichosanthes tricuspidata methanolic extract (TTME) against epilepsy mediated oxidative stress in pilocarpine induced mice. Intraperitonial administration of pilocarpine (85 mg/kg) induced seizure in mice was assessed by behavior observations, which is significantly (p < 0.05) reduced by TTME (100 and 200 mg/kg; i.p) in a dose dependant manner, similar to diazepam. Seizure was accompanied by significant increase in lipid peroxidation and the hippocampal nitrite content in pilocarpine group when compared with control. Moreover, the antioxidant enzymes superoxide dismutase, catalase and glutathione levels were decreased in pilocarpine administered groups. TTME administration attenuated oxidative damage as evident by decreased lipid oxidative damage and nitrite-nitrate content and restored the level of enzymatic antioxidant defenses in hippocampus. Involvement of free radicals during epilepsy is further confirmed by histopathological analysis which showed the loss of neuronal cells in hippocampus CA1 and CA3 pyramidal region. Our findings strongly support the hypothesis that TTME has anticonvulsant activity accompanied with the strong antioxidant potential plays a crucial role in reducing the oxidative stress produced by seizure.
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Aniol VA, Ivanova-Dyatlova AY, Keren O, Guekht AB, Sarne Y, Gulyaeva NV. A single pentylenetetrazole-induced clonic-tonic seizure episode is accompanied by a slowly developing cognitive decline in rats. Epilepsy Behav 2013; 26:196-202. [PMID: 23318024 DOI: 10.1016/j.yebeh.2012.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 11/04/2012] [Accepted: 12/08/2012] [Indexed: 12/13/2022]
Abstract
According to different studies, between 5% and 10% of people suffer a single isolated seizure episode at some time in their life. However, little is known about the effects of a single seizure episode on cognitive function, and clinical investigations of this issue are not easy to perform. In this situation, animal models may be a reasonable choice. The aim of our study was to follow the time course of delayed effects of generalized clonic-tonic convulsions on learning and memory functions in rats. A clonic-tonic seizure episode was induced by a single i.p. injection of pentylenetetrazole (70 mg/kg). Different behavioral tests were performed between days 10 and 100 after the convulsant administration. A single seizure episode resulted in a gradual decline in short-term memory function as assessed by novel object recognition and social recognition tests. The seizure episode induced a quick increase in hippocampal cell proliferation; however, the excessive newly generated cells seemed to be eliminated by the time of obvious cognitive impairment. These observations are indicative of a slowly developing and long-lasting influence of a single seizure episode on cognitive function. A rather long time period between the seizure episode and the manifestations of cognitive decline provides a window for a possible therapeutic intervention, and an elaboration of such "post-conditioning" treatments may be a promising opportunity to prevent subsequent mental impairments in patients.
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Affiliation(s)
- Victor A Aniol
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, RAS, Butlerov Street 5A, Moscow 117485, Russia
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Oxidative Stress Induced NMDA Receptor Alteration Leads to Spatial Memory Deficits in Temporal Lobe Epilepsy: Ameliorative Effects of Withania somnifera and Withanolide A. Neurochem Res 2012; 37:1915-27. [DOI: 10.1007/s11064-012-0810-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 05/11/2012] [Accepted: 05/26/2012] [Indexed: 10/28/2022]
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Inostroza M, Cid E, Menendez de la Prida L, Sandi C. Different emotional disturbances in two experimental models of temporal lobe epilepsy in rats. PLoS One 2012; 7:e38959. [PMID: 22720001 PMCID: PMC3376131 DOI: 10.1371/journal.pone.0038959] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 05/16/2012] [Indexed: 11/24/2022] Open
Abstract
Affective symptoms such as anxiety and depression are frequently observed in patients with epilepsy. The mechanisms of comorbidity of epilepsy and affective disorders, however, remain unclear. Diverse models are traditionally used in epilepsy research, including the status epilepticus (SE) model in rats, which are aimed at generating chronic epileptic animals; however, the implications of different SE models and rat strains in emotional behaviors has not been reported. To address this issue, we examined the emotional sequelae of two SE models of temporal lobe epilepsy (TLE)--the lithium-pilocarpine (LIP) model and the kainic acid (KA) model--in two different rat strains (Wistar and Sprague-Dawley), which differ significantly in the pattern and extent of TLE-associated brain lesions. We found differences between LIP- and KA-treated animals in tests for depression-like and anxiety-like behaviors, as well as differences in plasma corticosterone levels. Whereas only LIP-treated rats displayed increased motivation to consume saccharin, both SE models led to reduced motivation for social contact, with LIP-treated animals being particularly affected. Evaluation of behavior in the open field test indicated very low levels of anxiety in LIP-treated rats and a mild decrease in KA-treated rats compared to controls. After exposure to a battery of behavioral tests, plasma corticosterone levels were increased only in LIP-treated animals. This hyperactivity in the hypothalamus-pituitary-adrenocortical (HPA) axis was highly correlated with performance in the open field test and the social interaction test, suggesting that comorbidity of epilepsy and emotional behaviors might also be related to other factors such as HPA axis function. Our results indicate that altered emotional behaviors are not inherent to the epileptic condition in experimental TLE; instead, they likely reflect alterations in anxiety levels related to model-dependent dysregulation of the HPA axis.
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Affiliation(s)
- Marion Inostroza
- Instituto Cajal, Spanish National Research Council (CSIC), Madrid, Spain
- Departamento de Psicología, Universidad de Chile, Santiago, Chile
| | - Elena Cid
- Instituto Cajal, Spanish National Research Council (CSIC), Madrid, Spain
| | | | - Carmen Sandi
- Laboratory of Behavioral Genetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Federal de Lausanne (EPFL), Lausanne, Switzerland
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Langer M, Brandt C, Löscher W. Marked strain and substrain differences in induction of status epilepticus and subsequent development of neurodegeneration, epilepsy, and behavioral alterations in rats. Epilepsy Res 2011; 96:207-24. [DOI: 10.1016/j.eplepsyres.2011.06.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 05/30/2011] [Accepted: 06/04/2011] [Indexed: 10/18/2022]
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Hippocampal-dependent spatial memory in the water maze is preserved in an experimental model of temporal lobe epilepsy in rats. PLoS One 2011; 6:e22372. [PMID: 21829459 PMCID: PMC3144225 DOI: 10.1371/journal.pone.0022372] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 06/27/2011] [Indexed: 02/06/2023] Open
Abstract
Cognitive impairment is a major concern in temporal lobe epilepsy (TLE). While different experimental models have been used to characterize TLE-related cognitive deficits, little is known on whether a particular deficit is more associated with the underlying brain injuries than with the epileptic condition per se. Here, we look at the relationship between the pattern of brain damage and spatial memory deficits in two chronic models of TLE (lithium-pilocarpine, LIP and kainic acid, KA) from two different rat strains (Wistar and Sprague-Dawley) using the Morris water maze and the elevated plus maze in combination with MRI imaging and post-morten neuronal immunostaining. We found fundamental differences between LIP- and KA-treated epileptic rats regarding spatial memory deficits and anxiety. LIP-treated animals from both strains showed significant impairment in the acquisition and retention of spatial memory, and were unable to learn a cued version of the task. In contrast, KA-treated rats were differently affected. Sprague-Dawley KA-treated rats learned less efficiently than Wistar KA-treated animals, which performed similar to control rats in the acquisition and in a probe trial testing for spatial memory. Different anxiety levels and the extension of brain lesions affecting the hippocampus and the amydgala concur with spatial memory deficits observed in epileptic rats. Hence, our results suggest that hippocampal-dependent spatial memory is not necessarily affected in TLE and that comorbidity between spatial deficits and anxiety is more related with the underlying brain lesions than with the epileptic condition per se.
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Reid WM, Rolfe A, Register D, Levasseur JE, Churn SB, Sun D. Strain-related differences after experimental traumatic brain injury in rats. J Neurotrauma 2011; 27:1243-53. [PMID: 20392137 DOI: 10.1089/neu.2010.1270] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The present study directly compares the effects of experimental brain injury in two commonly used rat strains: Fisher 344 and Sprague-Dawley. We previously found that Fisher rats have a higher mortality rate and more frequent seizure attacks at the same injury level than Sprague-Dawley rats. Although strain differences in rats are commonly accepted as contributing to variability among studies, there is a paucity of literature addressing strain influence in experimental neurotrauma. Therefore this study compares outcome measures in two rat strains following lateral fluid percussion injury. Fisher 344 and Sprague-Dawley rats were monitored for changes in physiological measurements, intracranial pressure, and electroencephalographic activity. We further analyzed neuronal degeneration and cell death in the injured brain using Fluoro-Jade-B (FJB) histochemistry and caspase-3 immunostaining. Behavioral studies using the beam walk and Morris water maze were conducted to characterize strain differences in both motor and cognitive functional recovery following injury. We found that Fisher rats had significantly higher intracranial pressure, prolonged seizure activity, increased FJB-positive staining in the injured cortex and thalamus, and increased caspase-3 expression than Sprague-Dawley rats. On average, Fisher rats displayed a greater amount of total recording time in seizure activity and had longer ictal durations. The Fisher rats also had increased motor deficits, correlating with the above results. In spite of these results, Fisher rats performed better on cognitive tests following injury. The results demonstrate that different rat strains respond to injury differently, and thus in preclinical neurotrauma studies strain influence is an important consideration when evaluating outcomes.
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Affiliation(s)
- Wendy Murdock Reid
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, Virginia 23298-0631, USA.
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25
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Impaired auditory and contextual fear conditioning in soman-exposed rats. Pharmacol Biochem Behav 2011; 98:120-9. [DOI: 10.1016/j.pbb.2010.11.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 11/12/2010] [Accepted: 11/16/2010] [Indexed: 01/16/2023]
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26
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Júnior HVN, de França Fonteles MM, Mendes de Freitas R. Acute seizure activity promotes lipid peroxidation, increased nitrite levels and adaptive pathways against oxidative stress in the frontal cortex and striatum. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2011; 2:130-7. [PMID: 20592767 PMCID: PMC2763238 DOI: 10.4161/oxim.2.3.8488] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 03/12/2009] [Accepted: 03/19/2009] [Indexed: 01/30/2023]
Abstract
Previous experiments have shown that the generation of free radicals in rat brain homogenates is increased following pilocarpine-induced seizures and status epilepticus (SE). This study was aimed at investigating the changes in neurochemical mechanisms such as lipid peroxidation levels, nitrite content, glutathione reduced (GSH) concentration, superoxide dismutase and catalase activities in the frontal cortex and the striatum of Wistar adult rats after seizures and SE induced by pilocarpine. The control group was treated with 0.9% saline and another group of rats received pilocarpine (400 mg/kg, i.p.). Both groups were sacrificed 24 h after the treatments. Lipid peroxidation level, nitrite content, GSH concentration and enzymatic activities were measured by using spectrophotometric methods. Our findings showed that pilocarpine administration and its resulting seizures and SE produced a significant increase of lipid peroxidation level in the striatum (47%) and frontal cortex (59%). Nitrite contents increased 49% and 73% in striatum and frontal cortex in pilocarpine group, respectively. In GSH concentrations were decreases of 54% and 58% in the striatum and frontal cortex in pilocarpine group, respectively. The catalase activity increased 39% and 49% in the striatum and frontal cortex, respectively. The superoxide dismutase activity was not altered in the striatum, but it was present at a 24% increase in frontal cortex. These results suggest that there is a direct relationship between the lipid peroxidation and nitrite contents during epileptic activity that can be responsible for the superoxide dismutase and catalase enzymatic activity changes observed during the establishment of seizures and SE induced by pilocarpine.
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Freitas RM, Jordán J, Feng D. Lipoic acid effects on monoaminergic system after pilocarpine-induced seizures. Neurosci Lett 2010; 477:129-33. [PMID: 20433896 DOI: 10.1016/j.neulet.2010.04.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 04/20/2010] [Accepted: 04/20/2010] [Indexed: 11/18/2022]
Abstract
Systemic injection of pilocarpine has been shown to induce recurrent seizures and epileptic discharges demonstrated by EEG monitoring. It also has been reported that antioxidants are able to diminish or prevent the occurrence of epileptic discharges induced by pilocarpine through the inhibition of free radical formation and neurotransmitter metabolic alterations. The purpose of this work was to determine the effects of lipoic acid (LA) on the levels of dopamine (DA), serotonin (5-HT), norepinephrine (NE) and subsequent metabolites in the hippocampus of rats after seizure induction by pilocarpine. Seizures dramatically decreased the levels of DA, 5-hydroxyindoleacetic acid (5-HIAA) and NE, whereas significantly increased the levels of neurotransmitter metabolites. The administration of lipoic acid before seizure induction resulted in normalized levels of DA and 5-HA. However, the lipoic acid administration in similar conditions produced a reduction of the metabolites levels when compared with the pilocarpine group. These results suggest that the establishment of acute phase of seizures induced by pilocarpine might be produced by consequent the activation of serotonergic neurons. In addition, the lipoic acid inhibits hyperactivity of this system during the installation of pilocarpine-induced seizures.
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Affiliation(s)
- R M Freitas
- Laboratory of Physiology and Pharmacology of Federal University of Piauí, Picos, Piauí, Brazil.
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Portelli J, Aourz N, De Bundel D, Meurs A, Smolders I, Michotte Y, Clinckers R. Intrastrain differences in seizure susceptibility, pharmacological response and basal neurochemistry of Wistar rats. Epilepsy Res 2009; 87:234-46. [PMID: 19833479 DOI: 10.1016/j.eplepsyres.2009.09.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 09/16/2009] [Accepted: 09/18/2009] [Indexed: 10/20/2022]
Abstract
Reliable well-characterised animal models of seizures are necessary in order to better understand the underlying pathophysiological mechanisms as well as to screen potential anticonvulsant drugs. We currently use the focal pilocarpine model as an acute limbic seizure model. Due to breeding problems at the vendor, and apparent changes in pilocarpine-induced seizure susceptibility, we were forced to change breeding locations and vendors over a period of 2 years. Male Wistar rats were either purchased from two breeding locations of Charles River Laboratories (France and Germany), or obtained from Harlan Laboratories (The Netherlands). In the present retrospective study we evaluated the impact of these vendor changes on ketamine dosing to establish anaesthesia, on pilocarpine-induced seizure susceptibility, and on basal extracellular hippocampal noradrenaline, dopamine, serotonin, gamma-amino butyric acid, and glutamate levels of all pilocarpine-treated rats included in our studies. Significant differences were present in all of the parameters analyzed. This study clearly illustrates that intrastrain differences do exist from one vendor/breeding location to another, or even between rats from the same breeding location.
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Affiliation(s)
- Jeanelle Portelli
- Department of Pharmaceutical Chemistry, Drug Analysis & Drug Information, Vrije Universiteit Brussel, Brussels, Belgium
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29
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Investigation of oxidative stress involvement in hippocampus in epilepsy model induced by pilocarpine. Neurosci Lett 2009; 462:225-9. [DOI: 10.1016/j.neulet.2009.07.037] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 07/04/2009] [Accepted: 07/13/2009] [Indexed: 11/17/2022]
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30
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Wilhelm EA, Jesse CR, Bortolatto CF, Nogueira CW, Savegnago L. Anticonvulsant and antioxidant effects of 3-alkynyl selenophene in 21-day-old rats on pilocarpine model of seizures. Brain Res Bull 2009; 79:281-7. [PMID: 19480988 DOI: 10.1016/j.brainresbull.2009.03.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 03/18/2009] [Accepted: 03/23/2009] [Indexed: 11/24/2022]
Abstract
This study investigated the anticonvulsant effect of 3-alkynyl selenophene (3-ASP) on pilocarpine (PC)-, pentylenetetrazole (PTZ)- and kainic acid (KA)-induced seizures and mortality in 21-day-old rats. Rats were pretreated by oral route (p.o.) with 3-ASP (10, 25 and 50mg/kg) before intraperitoneal (i.p.) administration of PC (400mg/kg), PTZ (80 mg/kg) or KA (45 mg/kg). 3-ASP increased the latency to the seizure onset on PTZ and KA models. At the dose of 50mg/kg, 3-ASP avoided the death caused by PTZ and KA. 3-ASP (50mg/kg) abolished seizures and death induced by PC in rats. To investigate the antioxidant effect of 3-ASP on rats exposed to PC, the activity of glutathione peroxidase (GPx), glutathione-S-transferase (GST), acetylcholinesterase (AChE), Na(+)K(+)ATPase, superoxide dismutase (SOD) and catalase (CAT) as well as the levels of reactive species (RS) and ascorbic acid (AA) were determined in brains of rats. 3-ASP protected against the increase in RS levels and CAT activity induced by PC in brains of rats. The decrease in the levels of AA and inhibition of Na(+)K(+)ATPase, SOD and AChE activities caused by PC were protected by 3-ASP. Subeffective doses of 3-ASP plus diazepam, 5S,10R-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) or 6,7-dinitroquinoxaline-2,3-dione (DNQX) increased the latency to the seizure onset induced by PC, suggesting the involvement of ionotropic glutamatergic and GABAergic receptors in anticonvulsant action of 3-ASP. The anticonvulsant and antioxidant effects of 3-ASP in 21-day-old rats on PC model were demonstrated.
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Affiliation(s)
- Ethel A Wilhelm
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, CEP 97105-900, RS, Brazil
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Curia G, Longo D, Biagini G, Jones RS, Avoli M. The pilocarpine model of temporal lobe epilepsy. J Neurosci Methods 2008; 172:143-57. [PMID: 18550176 PMCID: PMC2518220 DOI: 10.1016/j.jneumeth.2008.04.019] [Citation(s) in RCA: 734] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 04/17/2008] [Accepted: 04/18/2008] [Indexed: 01/17/2023]
Abstract
Understanding the pathophysiogenesis of temporal lobe epilepsy (TLE) largely rests on the use of models of status epilepticus (SE), as in the case of the pilocarpine model. The main features of TLE are: (i) epileptic foci in the limbic system; (ii) an “initial precipitating injury”; (iii) the so-called “latent period”; and (iv) the presence of hippocampal sclerosis leading to reorganization of neuronal networks. Many of these characteristics can be reproduced in rodents by systemic injection of pilocarpine; in this animal model, SE is followed by a latent period and later by the appearance of spontaneous recurrent seizures (SRSs). These processes are, however, influenced by experimental conditions such as rodent species, strain, gender, age, doses and routes of pilocarpine administration, as well as combinations with other drugs administered before and/or after SE. In the attempt to limit these sources of variability, we evaluated the methodological procedures used by several investigators in the pilocarpine model; in particular, we have focused on the behavioural, electrophysiological and histopathological findings obtained with different protocols. We addressed the various experimental approaches published to date, by comparing mortality rates, onset of SRSs, neuronal damage, and network reorganization. Based on the evidence reviewed here, we propose that the pilocarpine model can be a valuable tool to investigate the mechanisms involved in TLE, and even more so when standardized to reduce mortality at the time of pilocarpine injection, differences in latent period duration, variability in the lesion extent, and SRS frequency.
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Affiliation(s)
- Giulia Curia
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and Physiology, McGill University, Montreal, QC, Canada H3A 2B4
| | - Daniela Longo
- Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, 41100 Modena, Italy
| | - Giuseppe Biagini
- Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, 41100 Modena, Italy
| | - Roland S.G. Jones
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, United Kingdom
| | - Massimo Avoli
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and Physiology, McGill University, Montreal, QC, Canada H3A 2B4
- Dipartimento di Medicina Sperimentale, Università di Roma “La Sapienza”, 00185 Roma, Italy
- Corresponding author at: 3801 University, Room 794, Montreal, QC, Canada H3A 2B4. Tel.: +1 514 398 1955; fax: +1 514 398 8106.
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Jesse CR, Savegnago L, Rocha JB, Nogueira CW. Neuroprotective effect caused by MPEP, an antagonist of metabotropic glutamate receptor mGluR5, on seizures induced by pilocarpine in 21-day-old rats. Brain Res 2008; 1198:197-203. [DOI: 10.1016/j.brainres.2008.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 12/24/2007] [Accepted: 01/03/2008] [Indexed: 11/26/2022]
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Barros DO, Xavier SML, Barbosa CO, Silva RF, Freitas RLM, Maia FD, Oliveira AA, Freitas RM, Takahashi RN. Effects of the vitamin E in catalase activities in hippocampus after status epilepticus induced by pilocarpine in Wistar rats. Neurosci Lett 2007; 416:227-30. [PMID: 17383094 DOI: 10.1016/j.neulet.2007.01.057] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 01/25/2007] [Accepted: 01/26/2007] [Indexed: 11/26/2022]
Abstract
Experimental manipulations suggest that in vivo administration of exogenous antioxidants agents decreases the concentration of free radical in the brain. Neurochemical studies have proposed a role for catalase in brain mechanisms responsible by development to status epilepticus (SE) induced by pilocarpine. The present study was aimed at was investigating the changes in catalase activities after pilocarpine-induced SE. Animals were treated with vitamin E (VIT E) 200 mg/kg (intraperitoneally (i.p.)) and, 30 min later, they received pilocarpine hydrochloride, 400 mg/kg, subcutaneous (s.c.) (P400). Other three groups received VIT E (200 mg/kg, i.p.), pilocarpine (400 mg/kg, s.c.) or 0.9% NaCl (control) alone. Animals were closely observed for behavioral changes, tremors, stereotyped movements, seizures, SE and death, for 24 h following the pilocarpine injection. The brains were dissected after decapitation. The results have shown that pilocarpine administration and resulting SE produced a significant increase in hippocampal catalase activity of (88%). In the group pre-treated which VIT E in hippocampal catalase activity was increase of 67% and 214% when compared with P400 and control group, respectively. Our results demonstrated a direct evidence of an increase in the activity of the hippocampal catalase of rat adults during seizure activity and after the pre-treated which VIT E that could be responsible by regulation of free radical levels during the establishment of SE.
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Affiliation(s)
- D O Barros
- Curso de Farmácia, Faculdade Católica Rainha do Sertão, Rua Juvêncio Alves, 660, Centro, Quixada, 63900-00, CE, Brazil
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Fujimoto Y, Kitaichi K, Nakayama H, Ito Y, Takagi K, Takagi K, Hasegawa T. The Pharmacokinetic Properties of Methamphetamine in Rats with Previous Repeated Exposure to Methamphetamine: The Differences between Long-Evans and Wistar Rats. Exp Anim 2007; 56:119-29. [PMID: 17460357 DOI: 10.1538/expanim.56.119] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Repeated treatment with methamphetamine (METH) causes long-term behavioral changes, so-called behavioral sensitization (BS), in humans as well as experimental animals. However, there are no reports as to whether repeated METH treatment can establish BS in stress-sensitive Long-Evans (LE) rats. Thus, we investigated the effect of repeated METH treatment (5 mg/kg x 5 days) on the establishment of BS in LE rats. Wistar (WIS) rats were used as a reference. In LE rats, repeated METH treatment failed to cause BS although it did enhance METH-induced hyperlocomotion in WIS rats. The levels of METH in brain dialysate and the ratio of the area under the concentration-time curve area in plasma to that in brain dialysate was increased in repeated METH-treated WIS rats as reported previously, but not in repeated METH-treated LE rats. METH increases plasma corticosterone (CORT) in both strains. However, the intensity of increment of CORT by repeated METH was lower in LE rats than that in WIS rats. Repeated METH treatment decreased the expression of METH-transposable and CORT-sensitive transporter, organic cation transporter 3 (OCT3), in the brain of WIS rats. However, the intensity of the decrement of OCT3 with repeated METH treatment was similar between both strains. Taken together, these results suggest that the lack of establishment of BS in LE rats might have been caused by the unchanged brain penetration of METH after repeated METH administration, and that the differential CORT response to METH is an important strain difference.
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Affiliation(s)
- Yohei Fujimoto
- Department of Medical Technology, Nagoya University School of Health Sciences, Nagoya, Japan
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Vales K, Bubenikova-Valesova V, Klement D, Stuchlik A. Analysis of sensitivity to MK-801 treatment in a novel active allothetic place avoidance task and in the working memory version of the Morris water maze reveals differences between Long-Evans and Wistar rats. Neurosci Res 2006; 55:383-8. [PMID: 16712995 DOI: 10.1016/j.neures.2006.04.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 04/04/2006] [Accepted: 04/07/2006] [Indexed: 01/17/2023]
Abstract
The aims of the present study were to compare the effect of subchronic administration of MK-801 on performance in the active allothetic place avoidance (AAPA) task and in the working version of Morris water maze (MWM) in Long-Evans and Wistar rats. Animals were trained for four daily sessions either in the AAPA or in the working memory version of the MWM. Wistar rats treated by MK-801 (0.1 mg/kg) showed a cognitive deficit in the AAPA task without a significant hyperlocomotion, whereas they were not impaired in the working memory version of the MWM compared to controls. Long-Evans rats treated by MK-801 (0.1 mg/kg) were not impaired either in the AAPA task or in the MWM task. Higher doses of MK-801 (0.2 and 0.3 mg/kg) produced hyperlocomotion in both strains which corresponded to an inability to solve both spatial tasks. Long-Evans rats were superior in the MWM to the Wistar rats in the groups treated with the low dose of MK-801. In conclusion, intact Wistar rats can efficiently solve both spatial tasks; however, they are more sensitive to MK-801-induced behavioural deficit. This has relevance for modeling of the schizophrenia-related deficits and for screening substances for their therapeutic potential.
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Affiliation(s)
- Karel Vales
- Institute of Physiology, Academy of Sciences, Videnska 1083, 14220 Prague 4, Czech Republic
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Freitas RM, Sousa FCF, Viana GSB, Fonteles MMF. Acetylcholinesterase activities in hippocampus, frontal cortex and striatum of Wistar rats after pilocarpine-induced status epilepticus. Neurosci Lett 2006; 399:76-8. [PMID: 16481111 DOI: 10.1016/j.neulet.2006.01.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2005] [Revised: 01/01/2006] [Accepted: 01/13/2006] [Indexed: 11/30/2022]
Abstract
Experimental manipulations suggest that in vivo administration of cholinergic agonists or inhibitors of acetylcholinesterase (AChE) increases the concentration of acetylcholine. Biochemical studies have proposed a role for AChE in brain mechanisms responsible by development to status epilepticus (SE) induced by pilocarpine. The present study was aimed at investigating the changes in AChE activities in hippocampus, striatum and frontal cortex of adult rats after pilocarpine-induced SE. The control group was treated with 0.9% saline (s.c., control group) and another group received pilocarpine (400 mg/kg, s.c.). Both groups were sacrificed 1 h after treatment. The results have shown that pilocarpine administration and resulting SE produced a significant decrease in the AChE activity in the hippocampus (63%), striatum (35%) and frontal cortex (27%) of adult rats. Our results demonstrated a direct evidence of a decrease in the activity of the AChE in rat brain regions during seizure activity that could be responsible by regulation of acetylcholine levels during the establishment of SE induced by pilocarpine.
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Affiliation(s)
- R M Freitas
- Laboratory of Neuropharmacology, Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceara, Rua Cel. Nunes de Melo 1127, 1210, Fortaleza 60431-970, CE, Brazil.
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Nascimento VS, Oliveira AA, Freitas RM, Sousa FCF, Vasconcelos SMM, Viana GSB, Fonteles MMF. Pilocarpine-induced status epilepticus: Monoamine level, muscarinic and dopaminergic receptors alterations in striatum of young rats. Neurosci Lett 2005; 383:165-70. [PMID: 15876489 DOI: 10.1016/j.neulet.2005.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 03/20/2005] [Accepted: 04/02/2005] [Indexed: 10/25/2022]
Abstract
Behavioural changes, muscarinic and dopaminergic receptors density and levels of monoamines were measured in striatum of rats after pilocarpine-induced status epilepticus (SE). Wistar rats at the age of 21 days were treated with pilocarpine (400mg/kg; subcutaneously) whilst the control group was treated with 0.9% saline (s.c.). Both groups were sacrificed 1h following the treatment. SE induced a muscarinic receptor downregulation of 64% in pilocarpine group. This effect was also observed to be 57% in D(1) and 32% in D(2). In the dissociation constant (K(d)) values in muscarinic and D(1) receptor no alterations were verified. On the other hand, the K(d) value for D(2) was observed to increase 41%. High performance liquid chromatography determinations showed 63, 35, 77 and 64% decreases in dopamine, 3-methoxy-phenylacetic acid, serotonin and 5-hydroxyindoleacetic acid contents, respectively. The homovanilic acid level was verified to increase 119%. The noradrenaline content was unaltered. A direct evidence of monoamine levels alterations can be verified during seizure activity and receptor density changes appear to occur in an accentuated way in immature brain during the estabilishment of SE induced by pilocarpine.
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Affiliation(s)
- V S Nascimento
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
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38
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Freitas RM, Vasconcelos SMM, Souza FCF, Viana GSB, Fonteles MMF. Oxidative stress in the hippocampus after pilocarpine-induced status epilepticus in Wistar rats. FEBS J 2005; 272:1307-12. [PMID: 15752349 DOI: 10.1111/j.1742-4658.2004.04537.x] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The role of oxidative stress in pilocarpine-induced status epilepticus was investigated by measuring lipid peroxidation level, nitrite content, GSH concentration, and superoxide dismutase and catalase activities in the hippocampus of Wistar rats. The control group was subcutaneously injected with 0.9% saline. The experimental group received pilocarpine (400 mg.kg(-1), subcutaneous). Both groups were killed 24 h after treatment. After the induction of status epilepticus, there were significant increases (77% and 51%, respectively) in lipid peroxidation and nitrite concentration, but a 55% decrease in GSH content. Catalase activity was augmented 88%, but superoxide dismutase activity remained unaltered. These results show evidence of neuronal damage in the hippocampus due to a decrease in GSH concentration and an increase in lipid peroxidation and nitrite content. GSH and catalase activity are involved in mechanisms responsible for eliminating oxygen free radicals during the establishment of status epilepticus in the hippocampus. In contrast, no correlations between superoxide dismutase and catalase activities were observed. Our results suggest that GSH and catalase activity play an antioxidant role in the hippocampus during status epilepticus.
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Affiliation(s)
- Rivelilson M Freitas
- Department of Physiology and Pharmacology, Laboratory of Neuropharmacology, School of Medicine, Federal University of Ceará, Fortaleza, Brazil.
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Abstract
PURPOSE Seizures and antiepileptic drugs (AEDs) are the main causes for cognitive impairment in persons with epilepsy. It is still a matter of debate whether carbamazepine (CBZ) improves cognition because of its own psychotropic effects or because it is more effective to treat temporal epilepsy. Our objective was to analyze the performance of CBZ-treated or nontreated pilocarpine epileptic rats in an object-recognition test. METHODS Twelve chronic pilocarpine-induced epileptic rats were treated with CBZ, 40 mg/kg, or saline, t.i.d. for 8 days. Twenty-one nonepileptic controls were treated with CBZ or saline. On day 8 of treatment, all rats were tested with an object-recognition paradigm. RESULTS No locomotor impairment was detected in chronic epilepsy or CBZ treatment, as exploration during training was not affected. Exploratory behaviors during the choice session were not decreased in rats treated with CBZ; therefore CBZ does not compromise procedural memory. Epileptic rats showed a nonsignificant change in the discrimination performance, and prolonged treatment with CBZ in epileptic rats induced a significant increase in object discrimination during the choice session. CONCLUSIONS Even though pilocarpine-induced epileptic animals do not show compromised performance in the spontaneous object-recognition test, prolonged CBZ treatment has a positive effect on a simple object-discrimination task. These results may be associated with the psychotropic effects of CBZ.
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Affiliation(s)
- Rosane B Bernardi
- Division of Basic and Clinical Pharmacology, Department of Physiological Sciences, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Brazil
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Freitas RM, Vasconcelos SMM, Souza FCF, Viana GSB, Fonteles MMF. Monoamine levels after pilocarpine-induced status epilepticus in hippocampus and frontal cortex of Wistar rats. Neurosci Lett 2004; 370:196-200. [PMID: 15488322 DOI: 10.1016/j.neulet.2004.08.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 08/09/2004] [Accepted: 08/11/2004] [Indexed: 11/20/2022]
Abstract
Pilocarpine-induced status epilepticus (SE) is an useful model to study the involvement of neurotransmitter systems as epileptogenesis modulators. Some researches have shown that pharmacological manipulations in dopaminergic, serotonergic, and noradrenergic systems alter the occurrence of pilocarpine-induced SE. The control group was treated with 0.9% saline (control group, s.c.). Another group of rats received pilocarpine (400mg/kg, s.c.) and both groups were sacrificed 24 h after the treatment. This work was performed to determine the alterations in monoamine levels (dopamine (DA), serotonin (5-HT) and norepinephrine (NE)) and their metabolites (3,4-hydroxyphenylacetic acid (DOPAC), homovanilic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA)) after pilocarpine-induced SE in hippocampus and frontal cortex of adult rats. The monoamines and their metabolites were determined by reverse-phase high-performance liquid chromatography with electrochemical detection. DA and 5-HIAA concentrations were not altered in the hippocampus of the pilocarpine group, but in the same group the 5-HT (160%), DOPAC (316%) and HVA (21%) levels increased, whereas, the NE (47%) content declined. For the frontal cortex determinations, there was an increase of 20 and 72% in DA and DOPAC levels, respectively, and a decrease in NE (32%), 5-HT (33%) and 5-HIAA (19%) concentrations, but HVA content remained unaltered. These results indicate that pilocarpine-induced SE can alter monoamine levels in different ways depending on the brain area studied, suggesting that different mechanisms are involved.
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Affiliation(s)
- R M Freitas
- Laboratory of Neuropharmacology, Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Rua Cel. Nunes de Melo 1127, Fortaleza 60431-970, CE, Brazil.
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Morimoto K, Fahnestock M, Racine RJ. Kindling and status epilepticus models of epilepsy: rewiring the brain. Prog Neurobiol 2004; 73:1-60. [PMID: 15193778 DOI: 10.1016/j.pneurobio.2004.03.009] [Citation(s) in RCA: 613] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Accepted: 03/24/2004] [Indexed: 01/09/2023]
Abstract
This review focuses on the remodeling of brain circuitry associated with epilepsy, particularly in excitatory glutamate and inhibitory GABA systems, including alterations in synaptic efficacy, growth of new connections, and loss of existing connections. From recent studies on the kindling and status epilepticus models, which have been used most extensively to investigate temporal lobe epilepsy, it is now clear that the brain reorganizes itself in response to excess neural activation, such as seizure activity. The contributing factors to this reorganization include activation of glutamate receptors, second messengers, immediate early genes, transcription factors, neurotrophic factors, axon guidance molecules, protein synthesis, neurogenesis, and synaptogenesis. Some of the resulting changes may, in turn, contribute to the permanent alterations in seizure susceptibility. There is increasing evidence that neurogenesis and synaptogenesis can appear not only in the mossy fiber pathway in the hippocampus but also in other limbic structures. Neuronal loss, induced by prolonged seizure activity, may also contribute to circuit restructuring, particularly in the status epilepticus model. However, it is unlikely that any one structure, plastic system, neurotrophin, or downstream effector pathway is uniquely critical for epileptogenesis. The sensitivity of neural systems to the modulation of inhibition makes a disinhibition hypothesis compelling for both the triggering stage of the epileptic response and the long-term changes that promote the epileptic state. Loss of selective types of interneurons, alteration of GABA receptor configuration, and/or decrease in dendritic inhibition could contribute to the development of spontaneous seizures.
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Affiliation(s)
- Kiyoshi Morimoto
- Department of Neuropsychiatry, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan
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Kubová H, Mares P, Suchomelová L, Brozek G, Druga R, Pitkänen A. Status epilepticus in immature rats leads to behavioural and cognitive impairment and epileptogenesis. Eur J Neurosci 2004; 19:3255-65. [PMID: 15217382 DOI: 10.1111/j.0953-816x.2004.03410.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It remains under dispute whether status epilepticus (SE) in the perinatal period or early childhood or the underlying neuropathology is the cause of functional impairment later in life. The present study examined whether SE induced by LiCl-pilocarpine in normal immature brain (at the age of 12 or 25 days; P12 or P25) causes cognitive decline and epileptogenesis, and the data were compared to those of rats undergoing SE as adults. Rats in the P12 group had impaired memory (repeated exposure to open-field paradigm) and emotional behaviour (lower proportion of open-arm entries and higher incidence of risk assessment period in elevated plus-maze) when assessed 3 months after SE, although not as severe as in the older age groups. Importantly, video-electroencephalography monitoring 3 months after SE demonstrated that 25% of rats in the P12 and 50% in P25 group developed spontaneous seizures. Only nonconvulsive seizures (ictal activity in hippocampus accompanied by automatisms) were recorded in the P12 group whereas rats in the P25 group exhibited clonic convulsions. The present findings indicate that SE is harmful to the immature brain as early as P12, which might be compared with early infancy in humans.
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Affiliation(s)
- Hana Kubová
- Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeòská 1083, Prague 4, CZ-142 20, Czech Republic.
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Freitas RM, Nascimento VS, Vasconcelos SMM, Sousa FCF, Viana GSB, Fonteles MMF. Catalase activity in cerebellum, hippocampus, frontal cortex and striatum after status epilepticus induced by pilocarpine in Wistar rats. Neurosci Lett 2004; 365:102-5. [PMID: 15245787 DOI: 10.1016/j.neulet.2004.04.060] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2004] [Revised: 04/11/2004] [Accepted: 04/25/2004] [Indexed: 11/20/2022]
Abstract
The mechanism underlying the vulnerability of the brain to status epilepticus (SE) induced by pilocarpine remains unknown. Oxidative stress has been implicated in a variety of acute and chronic neurologic conditions, including SE. The present study was aimed at was investigating the changes in catalase activity after pilocarpine-induced seizures and SE. The Control group was treated with 0.9% saline (NaCl, subcutaneously (s.c.)) and sacrificed 1h after the treatment. Another group was treated with pilocarpine (400 mg/kg, s.c., Pilocarpine group) and sacrificed 1h after treatment. The catalase activity in the cerebellum, hippocampus, frontal cortex and striatum of Wistar rats was determined. The results have shown that pilocarpine administration and resulting SE produced a significant increase in the catalase activity in the hippocampus (36%), striatum (31%) and frontal cortex (15%) of treated adult rats. Nevertheless, in the adult rat cerebellum after SE induced by pilocarpine no change was observed in the catalase activity. Our results demonstrated a direct evidence of an increase in the activity of the scavenging enzyme (catalase) in different cerebral structures during seizure activity that could be responsible for eliminating oxygen free radicals and might be one of the compensatory mechanisms to avoid the development of oxidative stress during the establishment of SE induced by pilocarpine. Our reports also indicate clear regional differences in the catalase activity caused by pilocarpine-induced seizures and SE and the hippocampus might be the principal area affected and cerebellum does not modify for this parameter studied during epileptic activity.
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Affiliation(s)
- R M Freitas
- Laboratory of Neuropharmacology, Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Rua Frederico Severo 201, Ap 103, Bl 07, Messejana, Fortaleza 60830-310, Brazil.
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McKay BE, Persinger MA. Normal spatial and contextual learning for ketamine-treated rats in the pilocarpine epilepsy model. Pharmacol Biochem Behav 2004; 78:111-9. [PMID: 15159140 DOI: 10.1016/j.pbb.2004.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2003] [Revised: 12/05/2003] [Accepted: 02/27/2004] [Indexed: 11/18/2022]
Abstract
Cognitive impairments frequently accompany epileptic disorders. Here, we examine two neuroprotective agents, the noncompetitive NMDA antagonist ketamine and the dopaminergic antagonist acepromazine, for their efficacy in attenuating cognitive impairments in the lithium-pilocarpine (LI-PILO) model of rat limbic epilepsy. Declarative-like cognitive behaviors were assessed in a Morris water maze task that consisted successively of spatial and nonspatial (cued platform) training. Whereas the ketamine-treated (Ket) LI-PILO rats performed equally in all respects to nonseized control rats for the spatial and nonspatial components of the water maze task, the acepromazine-treated (Ace) LI-PILO rats failed to demonstrate learning in either the hidden or cued platform variants of the task and did not demonstrate any place learning in the platform-removed probe trials. We further assessed nondeclarative (associative) cognitive behaviors with a standard contextual fear-conditioning protocol. LI-PILO rats treated with acepromazine failed to learn the Pavlovian relationship; Ket LI-PILO rats performed equivalently to nonseized controls. Cumulatively, these data suggest robust cognitive sparing for LI-PILO rats with pharmacological NMDA receptor antagonism following induction of status epilepticus (SE). This cognitive sparing occurs despite earlier findings that the mean amount of total brain damage with LI-PILO is equivalent for Ket and Ace rats.
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Affiliation(s)
- B E McKay
- Behavioral Neuroscience Laboratory, Laurentian University, Sudbury, Ontario, Canada P3E 2C6.
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Abstract
Data from experimental models provide evidence that both prolonged and brief seizures can cause irreversible impairment in spatial and emotional learning and memory. Factors related to the severity of the behavioral impairments include genetic background, age at the time of the epileptogenic insult, extent of brain lesion, location of seizure focus, seizure duration, seizure number, brain reserve, and environmental and social living conditions. Further, as in humans, the interval between the last seizure and behavioral testing as well as treatment with antiepileptic drugs can affect the test results.
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Affiliation(s)
- Katarzyna Majak
- Epilepsy Research Laboratory, Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland
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Abstract
Status epilepticus (StE) in immature rats causes long-term functional impairment. Whether this is associated with structural alterations remains controversial. The present study was designed to test the hypothesis that StE at an early age results in neuronal loss. StE was induced with lithium-pilocarpine in 12-d-old rats, and the presence of neuronal damage was investigated in the brain from 12 hr up to 1 week later using silver and Fluoro-Jade B staining techniques. Analysis of the sections indicated consistent neuronal damage in the central and lateral segments of the mediodorsal nucleus of the thalamus, which was confirmed using adjacent cresyl violet-stained preparations. The mechanism of thalamic damage (necrosis vs apoptosis) was investigated further using TUNEL, immunohistochemistry for caspase-3 and cytochrome c, and electron microscopy. Activated microglia were detected using OX-42 immunohistochemistry. The presence of silver and Fluoro-Jade B-positive degenerating neurons in the mediodorsal thalamic nucleus was associated with the appearance of OX-42-immunopositive activated microglia but not with the expression of markers of programmed cell death, caspase-3, or cytochrome c. Electron microscopy revealed necrosis of the ultrastructure of damaged neurons, providing further evidence that the mechanism of StE-induced damage in the mediodorsal thalamic nucleus at postnatal day 12 is necrosis rather than apoptosis. Finally, these data together with previously described functions of the medial and lateral segments of the mediodorsal thalamic nucleus suggest that some functions, such as adaptation to novelty, might become compromised after StE early in development.
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