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Boo KJ, Kim DH, Cho E, Kim DH, Jeon SJ, Shin CY. Neonatal dysregulation of 2-arachidonoylglycerol induces impaired brain function in adult mice. Neuropharmacology 2024; 257:110045. [PMID: 38885736 DOI: 10.1016/j.neuropharm.2024.110045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 06/03/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024]
Abstract
The endocannabinoid system (ECS) regulates neurotransmission linked to synaptic plasticity, cognition, and emotion. While it has been demonstrated that dysregulation of the ECS in adulthood is relevant not only to central nervous system (CNS) disorders such as autism spectrum disorder, cognitive dysfunction, and depression but also to brain function, there are few studies on how dysregulation of the ECS in the neonatal period affects the manifestation and pathophysiology of CNS disorders later in life. In this study, DO34, a diacylglycerol lipase alpha (DAGLα) inhibitor affecting endocannabinoid 2-AG production, was injected into C57BL/6N male mice from postnatal day (PND) 7 to PND 10, inducing dysregulation of the ECS in the neonatal period. Subsequently, we examined whether it affects neuronal function in adulthood through electrophysiological and behavioral evaluation. DO34-injected mice showed significantly decreased cognitive functions, attributed to impairment of hippocampal synaptic plasticity. The findings suggest that regulation of ECS activity in the neonatal period may induce enduring effects on adult brain function.
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Affiliation(s)
- Kyung-Jun Boo
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Dae Hyun Kim
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea
| | - Eunbi Cho
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea; Institute of Biomedical Sciences & Technology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Dong Hyun Kim
- Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea; Institute of Biomedical Sciences & Technology, Konkuk University, Seoul, 05029, Republic of Korea.
| | - Se Jin Jeon
- Department of Pharmacology, College of Medicine, Hallym University, Chuncheon, Gangwon, 24252, Republic of Korea.
| | - Chan Young Shin
- School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul, 05029, Republic of Korea; Department of Pharmacology and Department of Advanced Translational Medicine, School of Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea; Institute of Biomedical Sciences & Technology, Konkuk University, Seoul, 05029, Republic of Korea.
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2
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Cruz Del Angel Y, Orfila JE, Herson PS, Brooks-Kayal A, González MI. Down-regulation of AMPA receptors and long-term potentiation during early epileptogenesis. Epilepsy Behav 2021; 124:108320. [PMID: 34592633 DOI: 10.1016/j.yebeh.2021.108320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022]
Abstract
Epilepsy is a brain disorder characterized by the occurrence of recurrent spontaneous seizures. Behavioral disorders and altered cognition are frequent comorbidities affecting the quality of life of people with epilepsy. These impairments are undoubtedly multifactorial and the specific mechanisms underlying these comorbidities are largely unknown. Long-lasting alterations in synaptic strength due to changes in expression, phosphorylation, or function of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) have been associated with alterations in neuronal synaptic plasticity. In particular, alterations in hippocampal long-term potentiation (LTP), a well-accepted model of learning and memory, have been associated with altered cognition in epilepsy. Here, we analyzed the effects of pilocarpine-induced status epilepticus (SE) on AMPARs to determine if alterations in AMPAR signaling might be one of the mechanisms contributing to altered cognition during epilepsy. We found alterations in the phosphorylation and plasma membrane expression of AMPARs. In addition, we detected altered expression of GRIP, a key scaffolding protein involved in the proper distribution of AMPARs at the neuronal cell surface. Interestingly, a functional analysis revealed that these molecular changes are linked to impaired LTP. Together, these observations suggest that seizure-induced alterations in the molecular machinery regulating AMPARs likely impact the neuron's ability to support synaptic plasticity that is required for learning and memory.
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Affiliation(s)
- Yasmin Cruz Del Angel
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - James E Orfila
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paco S Herson
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Amy Brooks-Kayal
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Children's Hospital Colorado, Aurora, CO 80045, USA
| | - Marco I González
- Department of Pediatrics, Division of Neurology and Translational Epilepsy Research Program, University of Colorado School of Medicine, Aurora, CO 80045, USA; Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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3
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Faraz M, Kosarmadar N, Rezaei M, Zare M, Javan M, Barkley V, Shojaei A, Mirnajafi-Zadeh J. Deep brain stimulation effects on learning, memory and glutamate and GABA A receptor subunit gene expression in kindled rats. Acta Neurobiol Exp (Wars) 2021; 81:43-57. [PMID: 33949168 DOI: 10.21307/ane-2021-006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 01/14/2021] [Indexed: 11/11/2022]
Abstract
Epileptic seizures are accompanied by learning and memory impairments. In this study, the effect of low frequency stimulation (LFS) on spatial learning and memory was assessed in kindled animals and followed for one month. Fully kindled rats received LFS at 4 times (immediately, 6 h, 24 h and 30 h following the final kindling stimulation). Applying LFS improved kindled animals' performance in the Barnes maze test. This LFS action was accompanied by a decrease in NR2B gene expression, an increase in the gene expression of the α subunit of calcineurin A and an increased NR2A/NR2B ratio in kindled animals. In addition, the gene expression of the GABAA receptor γ2 subunit increased at 2-3 h after applying LFS. The increase in NR2A/NR2B ratio was also observed 1 week after LFS. No significant changes were observed one month after LFS administration. Field potential recordings in the hippocampal CA1 area showed that kindling-induced potentiation of the field EPSP slope returned to near baseline when measured 2-3 h after applying LFS. Therefore, it may be postulated that applying LFS in kindled animals reduced the seizure-induced learning and memory impairments, albeit time-dependently. In tandem, LFS prevented kindling-induced alterations in gene expression of the described proteins, which are potentially important for synaptic transmission and/or potentiation. Moreover, a depotentiation-like phenomenon may be a possible mechanism underlying the LFS action. Epileptic seizures are accompanied by learning and memory impairments. In this study, the effect of low frequency stimulation (LFS) on spatial learning and memory was assessed in kindled animals and followed for one month. Fully kindled rats received LFS at 4 times (immediately, 6 h, 24 h and 30 h following the final kindling stimulation). Applying LFS improved kindled animals’ performance in the Barnes maze test. This LFS action was accompanied by a decrease in NR2B gene expression, an increase in the gene expression of the α subunit of calcineurin A and an increased NR2A/NR2B ratio in kindled animals. In addition, the gene expression of the GABAA receptor γ2 subunit increased at 2–3 h after applying LFS. The increase in NR2A/NR2B ratio was also observed 1 week after LFS. No significant changes were observed one month after LFS administration. Field potential recordings in the hippocampal CA1 area showed that kindling-induced potentiation of the field EPSP slope returned to near baseline when measured 2–3 h after applying LFS. Therefore, it may be postulated that applying LFS in kindled animals reduced the seizure-induced learning and memory impairments, albeit time-dependently. In tandem, LFS prevented kindling-induced alterations in gene expression of the described proteins, which are potentially important for synaptic transmission and/or potentiation. Moreover, a depotentiation-like phenomenon may be a possible mechanism underlying the LFS action.
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Affiliation(s)
- Mona Faraz
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Nastaran Kosarmadar
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Mahmoud Rezaei
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Meysam Zare
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran
| | - Mohammad Javan
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran ; Institute for Brain Sciences and Cognition , Tarbiat Modares University , Tehran , Iran
| | - Victoria Barkley
- Krembil Research Institute , University Health Network , Toronto , Canada
| | - Amir Shojaei
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran ; Institute for Brain Sciences and Cognition , Tarbiat Modares University , Tehran , Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology , Faculty of Medical Sciences , Tarbiat Modares University , Tehran , Iran ; Institute for Brain Sciences and Cognition , Tarbiat Modares University , Tehran , Iran
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Sadeghian A, Salari Z, Azizi H, Raoufy MR, Shojaei A, Kosarmadar N, Zare M, Rezaei M, Barkley V, Javan M, Fathollahi Y, Mirnajafi-Zadeh J. The role of dopamine D 2-like receptors in a "depotentiation-like effect" of deep brain stimulation in kindled rats. Brain Res 2020; 1738:146820. [PMID: 32251663 DOI: 10.1016/j.brainres.2020.146820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 01/12/2023]
Abstract
The mechanisms involved in the anti-seizure effects of low-frequency stimulation (LFS) have not been completely determined. However, Gi-protein-coupled receptors, including D2-like receptors, may have a role in mediating these effects. In the present study, the role of D2-like receptors in LFS' anti-seizure action was investigated. Rats were kindled with semi-rapid (6 stimulations per day), electrical stimulation of the hippocampal CA1 area. In LFS-treated groups, subjects received four trials of LFS at 5 min, 6 h, 24 h, and 30 h following the last kindling stimulation. Each LFS set occurred at 5 min intervals, and consisted of 4 trains. Each train contained 200, 0/1 ms long, monophasic square wave pulses at 1 Hz. Haloperidol (D2-like receptors antagonist, 2 µm) and/or bromocriptine (D2-like receptors agonist 2 µg/µlit) were microinjected into the lateral ventricle immediately after the last kindling, before applying LFS. Obtained results showed that applying LFS in fully-kindled subjects led to a depotentiation-like decrease in kindling-induced potentiation and reduced the amplitude and rise slope of excitatory and inhibitory post-synaptic currents in whole-cell recordings from CA1 pyramidal neurons. In addition, LFS restored the kindling-induced, spatial learning and memory impairments in the Barnes maze test. A D2-like receptor antagonist inhibited these effects of LFS, while a D2-like receptor agonist mimicked these effects. In conclusion, a depotentiation-like mechanism may be involved in restoring LFS' effects on learning and memory, and synaptic plasticity. These effects depend on D2-like receptors activity.
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Affiliation(s)
- Azam Sadeghian
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zahra Salari
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Hossein Azizi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Reza Raoufy
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Nastaran Kosarmadar
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Meysam Zare
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mahmoud Rezaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Victoria Barkley
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Mohammad Javan
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Yaghoub Fathollahi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran, Iran.
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Wang W, Kiyoshi CM, Du Y, Taylor AT, Sheehan ER, Wu X, Zhou M. TREK-1 Null Impairs Neuronal Excitability, Synaptic Plasticity, and Cognitive Function. Mol Neurobiol 2020; 57:1332-1346. [PMID: 31728930 PMCID: PMC8808335 DOI: 10.1007/s12035-019-01828-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023]
Abstract
TREK-1, a two-pore-domain K+ channel, is highly expressed in the central nervous system. Although aberrant expression of TREK-1 is implicated in cognitive impairment, the cellular and functional mechanism underlying this channelopathy is poorly understood. Here we examined TREK-1 contribution to neuronal morphology, excitability, synaptic plasticity, and cognitive function in mice deficient in TREK-1 expression. TREK-1 immunostaining signal mainly appeared in hippocampal pyramidal neurons, but not in astrocytes. TREK-1 gene knockout (TREK-1 KO) increases dendritic sprouting and the number of immature spines in hippocampal CA1 pyramidal neurons. Functionally, TREK-1 KO increases neuronal excitability and enhances excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs). The increased EPSCs appear to be attributed to an increased release probability of presynaptic glutamate and functional expression of postsynaptic AMPA receptors. TREK-1 KO decreased the paired-pulse ratio and severely occluded the long-term potentiation (LTP) in the CA1 region. These altered synaptic transmission and plasticity are associated with recognition memory deficit in TREK-1 KO mice. Although astrocytic expression of TREK-1 has been reported in previous studies, TREK-1 KO does not alter astrocyte membrane K+ conductance or the syncytial network function in terms of syncytial isopotentiality. Altogether, TREK-1 KO profoundly affects the cellular structure and function of hippocampal pyramidal neurons. Thus, the impaired cognitive function in diseases associated with aberrant expression of TREK-1 should be attributed to the failure of this K+ channel in regulating neuronal morphology, excitability, synaptic transmission, and plasticity.
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Affiliation(s)
- Wei Wang
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
- Department of Physiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Conrad M Kiyoshi
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Yixing Du
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Anne T Taylor
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Erica R Sheehan
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Xiao Wu
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Min Zhou
- Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
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Liu H, Stover KR, Sivanenthiran N, Chow J, Cheng C, Liu Y, Lim S, Wu C, Weaver DF, Eubanks JH, Song H, Zhang L. Impaired Spatial Learning and Memory in Middle-Aged Mice with Kindling-Induced Spontaneous Recurrent Seizures. Front Pharmacol 2019; 10:1077. [PMID: 31611787 PMCID: PMC6768971 DOI: 10.3389/fphar.2019.01077] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 08/23/2019] [Indexed: 02/06/2023] Open
Abstract
Temporal lobe epilepsy is the most common and often drug-resistant type of epilepsy in the adult and aging populations and has great diversity in etiology, electro-clinical manifestations, and comorbidities. Kindling through repeated brief stimulation of limbic structures is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling can induce spontaneous recurrent seizures in several animal species. However, kindling studies in middle-aged, aging, or aged animals remain scarce, and currently, little is known about kindling-induced behavioral changes in middle-aged/aging animals. We therefore attempted to provide more information in this area using a mouse model of extended hippocampal kindling. We conducted experiments in middle-aged mice (C57BL/6, male, 12-14 months of age) to model new-onset epilepsy in adult/aging populations. Mice experienced twice daily hippocampal stimulations or handling manipulations for 60-70 days and then underwent continuous electroencephalogram (EEG)-video monitoring to detect spontaneous recurrent seizures. Extended kindled mice consistently exhibited spontaneous recurrent seizures with mean incidences of 6-7 events per day, and these seizures featured EEG discharges and corresponding convulsions. The handling control mice showed neither seizure nor aberrant EEG activity. The two groups of mice underwent the Morris water maze test of spatial learning and memory 1-2 weeks after termination of the kindling stimulation or handling manipulation. During visible platform trials, the kindled mice took a longer distance and required more time than the control mice to find the platform. During hidden platform trials, the kindled mice showed no improvement over 5-day trials in finding the platform whereas the control mice improved significantly. During probe tests in which the hidden platform was removed, the kindled mice spent less time than the controls searching in the correct platform location. There were no significant differences between the kindled and control mice with respect to swim speed or total locomotor activity in an open-field test. Together, these observations indicate that the extended kindled mice with spontaneous recurrent seizures are impaired in spatial learning and memory as assessed by the Morris water maze test. We postulate that the extended hippocampal kindling in middle-aged mice may help explore epileptogenic mechanisms and comorbidities potentially relevant to new-onset temporal lobe epilepsy in adult and aging patients. Limitations and confounds of our present experiments are discussed to improve future examinations of epileptic comorbidities in extended kindled mice.
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Affiliation(s)
- Haiyu Liu
- Department of Neurosurgery, The First Hospital of Jilin University, Jilin, China
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Kurt R. Stover
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Nila Sivanenthiran
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Jonathan Chow
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Chloe Cheng
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Yapeng Liu
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Donald F. Weaver
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Chemistry, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - James H. Eubanks
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Hongmei Song
- Department of Neurosurgery, The First Hospital of Jilin University, Jilin, China
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
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Ghotbeddin Z, Moazedi AA, Yadollahpour A, Rendi F, Jalilifar M. Improving cognitive task in kindled rats by using low frequency stimulation during epileptogenesis. Metab Brain Dis 2018; 33:1525-1531. [PMID: 29959601 DOI: 10.1007/s11011-018-0260-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 05/28/2018] [Indexed: 11/08/2022]
Abstract
Numerous studies indicate that one of the bad effects of epilepsy is cognitive impairment. In this study we focused on the effect of LFS as a potential anticonvulsant agent, during epileptogenesis on cognitive impairments induced by amygdala kindling in rat. Twenty-one adult rats were divided into 3 groups including control (n = 7), kindled (n = 7), and Kindled+LFS (KLFS) (n = 7). Animals in the kindled group received kindling stimulation in a rapid kindling manner (a 3 s train of 50 Hz monophasic pulses of 1 ms duration, 12 times a day) in amygdala whereas control animals had no stimulation. Four packages of LFS (each package consisting of 200 monophasic square pulses, 0.1 ms pulse duration at 1 Hz) were applied daily after termination of kindling stimulation in KLFS group. Spatial memory of all animals was tested using radial arm maze after termination of stimulation on acquisition trial days and 14 days after the final acquisition trial test. Epileptogenesis process significantly increased working and reference memory error compared to control groups whereas application of LFS immediately after kindling stimulation prevented this impairment in 8 arm radial maze and there was no significant difference between KLS and control groups. Our results indicated that application of LFS during kindling acquisition suppresses memory impairment in epileptogenesis by kindling stimulation.
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Affiliation(s)
- Zohreh Ghotbeddin
- Department of Physiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
- Stem Cell and Transgenic Technology Research Center, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
| | - Ahmad Ali Moazedi
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Ali Yadollahpour
- Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Faezeh Rendi
- Department of Basic Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, P.O. Box: 61357-83151, Ahvaz, Iran
| | - Mostafa Jalilifar
- Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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Esmaeilpour K, Sheibani V, Shabani M, Mirnajafi-Zadeh J, Akbarnejad Z. Low Frequency Stimulation Reverses the Kindling-Induced Impairment of Learning and Memory in the Rat Passive-avoidance Test. Basic Clin Neurosci 2018; 9:51-58. [PMID: 29942440 PMCID: PMC6015633 DOI: 10.29252/nirp.bcn.9.1.51] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Introduction: The life quality of patients with epileptic seizures is highly affected by cognitive deficits. Low Frequency Stimulation (LFS) is a novel approach for the treatment of pharmacoresistant epilepsy. The main goal of this research is investigating the possible effect of LFS on seizure-induced cognitive dysfunction. Methods: To this end, the kindled animal were prepared via CA1 electrical stimulation in a semi-rapid way (12 stimulations/day). A group of animals were stimulated with LFS, 4 times at 30 s, 6 h, 24 h, and 30 h after the last kindling stimulation. Applied LFS was administered in 4 packages every 5 minutes. The packages were designed with 200 monophasic 200 monophasic square wave pulses of 0.1 ms duration at 1 Hz. The passive-avoidance test was conducted on all animals in order to measure the learning and memory behavior. Results: Hippocampal kindled rats showed deficits in learning and memory when passive avoidance test was performed. Application of LFS reversed the impairment in learning and memory behavior in kindled rats. At the same time, LFS markedly diminished kindling-induced neuronal loss and atrophy in the hippocampus. Conclusion: LFS may have some protection against seizure-induced cognitive damage in kindled rats.
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Affiliation(s)
- Khadijeh Esmaeilpour
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Sheibani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Shabani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Zeinab Akbarnejad
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
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9
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Esmaeilpour K, Sheibani V, Shabani M, Mirnajafi-Zadeh J. Low frequency electrical stimulation has time dependent improving effect on kindling-induced impairment in long-term potentiation in rats. Brain Res 2017; 1668:20-27. [DOI: 10.1016/j.brainres.2017.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 04/28/2017] [Accepted: 05/08/2017] [Indexed: 10/19/2022]
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10
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Esmaeilpour K, Sheibani V, Shabani M, Mirnajafi-Zadeh J. Effect of low frequency electrical stimulation on seizure-induced short- and long-term impairments in learning and memory in rats. Physiol Behav 2016; 168:112-121. [PMID: 27825910 DOI: 10.1016/j.physbeh.2016.11.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/31/2016] [Accepted: 11/03/2016] [Indexed: 12/21/2022]
Abstract
Kindled seizures can impair learning and memory. In the present study the effect of low-frequency electrical stimulation (LFS) on kindled seizure-induced impairment in spatial learning and memory was investigated and followed up to one month. Animals were kindled by electrical stimulation of hippocampal CA1 area in a semi-rapid manner (12 stimulations per day). One group of animals received four trials of LFS at 30s, 6h, 24h, and 30h following the last kindling stimulation. Each LFS trial was consisted of 4 packages at 5min intervals. Each package contained 200 monophasic square wave pulses of 0.1ms duration at 1Hz. The Open field, Morris water maze, and novel object recognition tests were done 48h, 1week, 2weeks, and one month after the last kindling stimulation respectively. Kindled animals showed a significant impairment in learning and memory compared to control rats. LFS decreased the kindling-induced learning and memory impairments at 24h and one week following its application, but not at 2week or 1month after kindling. In the group of animals that received the same 4 trials of LFS again one week following the last kindling stimulation, the improving effect of LFS was observed even after one month. Obtained results showed that application of LFS in fully kindled animals has a long-term improving effect on spatial learning and memory. This effect can remain for a long duration (one month in this study) by increasing the number of applied LFS.
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Affiliation(s)
- Khadijeh Esmaeilpour
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Sheibani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Shabani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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Ghafouri S, Fathollahi Y, Javan M, Shojaei A, Asgari A, Mirnajafi-Zadeh J. Effect of low frequency stimulation on impaired spontaneous alternation behavior of kindled rats in Y-maze test. Epilepsy Res 2016; 126:37-44. [DOI: 10.1016/j.eplepsyres.2016.06.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 05/28/2016] [Accepted: 06/25/2016] [Indexed: 10/21/2022]
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12
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What is more harmful, seizures or epileptic EEG abnormalities? Is there any clinical data? Epileptic Disord 2016; 16 Spec No 1:S12-22. [PMID: 25323031 DOI: 10.1684/epd.2014.0686] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cognitive impairment is a common and often devastating co-morbidity of childhood epilepsy. While the aetiology of the epilepsy is a critical determinant of cognitive outcome, there is considerable evidence from both rodent and human studies that indicate that seizures and interictal epileptiform abnormalities can contribute to cognitive impairment. A critical feature of childhood epilepsy is that the seizures and epileptiform activity occur in a brain with developing, plastic neuronal circuits. The consequences of seizures and interictal epileptiform activity in the developing brain differ from similar paroxysmal events occurring in the relatively fixed circuitry of the mature brain. In animals, it is possible to study interictal spikes independently from seizures, and it has been demonstrated that interictal spikes are as detrimental as seizures during brain development. In the clinic, distinguishing the differences between interictal spikes and seizures is more difficult, since both typically occur together. However, both seizures and interictal spikes result in transient cognitive impairment. Recurrent seizures, particularly when frequent, can lead to cognitive regression. While the clinical data linking interictal spikes to persistent cognitive impairment is limited, interictal spikes occurring during the formation and stabilization of neuronal circuits likely contribute to aberrant connectivity. There is insufficient clinical literature to indicate whether interictal spikes are more detrimental than seizures during brain development.
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13
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Excitatory synapses are stronger in the hippocampus of Rett syndrome mice due to altered synaptic trafficking of AMPA-type glutamate receptors. Proc Natl Acad Sci U S A 2016; 113:E1575-84. [PMID: 26929363 DOI: 10.1073/pnas.1517244113] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Deficits in long-term potentiation (LTP) at central excitatory synapses are thought to contribute to cognitive impairments in neurodevelopmental disorders associated with intellectual disability and autism. Using the methyl-CpG-binding protein 2 (Mecp2) knockout (KO) mouse model of Rett syndrome, we show that naïve excitatory synapses onto hippocampal pyramidal neurons of symptomatic mice have all of the hallmarks of potentiated synapses. Stronger Mecp2 KO synapses failed to undergo LTP after either theta-burst afferent stimulation or pairing afferent stimulation with postsynaptic depolarization. On the other hand, basal synaptic strength and LTP were not affected in slices from younger presymptomatic Mecp2 KO mice. Furthermore, spine synapses in pyramidal neurons from symptomatic Mecp2 KO are larger and do not grow in size or incorporate GluA1 subunits after electrical or chemical LTP. Our data suggest that LTP is occluded in Mecp2 KO mice by already potentiated synapses. The higher surface levels of GluA1-containing receptors are consistent with altered expression levels of proteins involved in AMPA receptor trafficking, suggesting previously unidentified targets for therapeutic intervention for Rett syndrome and other MECP2-related disorders.
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Wang Q, Li M, Du W, Shao F, Wang W. The different effects of maternal separation on spatial learning and reversal learning in rats. Behav Brain Res 2014; 280:16-23. [PMID: 25479401 DOI: 10.1016/j.bbr.2014.11.040] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/20/2014] [Accepted: 11/25/2014] [Indexed: 01/26/2023]
Abstract
Early postnatal maternal separation (MS) can play an important role in the development of psychopathologies during ontogeny. In the present study, we investigated the effects of repeated MS (4h per day from postnatal day (PND) 1 to 21) on locomotor activity and anxiety behavior in open field, spatial learning and reversal learning in Morris water maze of male and female juvenile (PND 21), adolescent (PND 35) and early adult (PND 56) Wistar rats. The results indicated that MS increased locomotor activity of rats across all ages and reduced anxiety behavior of adolescent rats in open field test. MS also increased swim distance in spatial learning and decreased escape latency in reversal learning in adolescent and early adult rats. Additionally, for socially reared rats, there was increased spontaneous locomotion with age, decreased reversal learning ability with age. The present study provides novel insights into the consequences of MS and demonstrates unique age-dependent changes at the behavioral levels.
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Affiliation(s)
- Qiong Wang
- Department of Psychology, Peking University, Beijing 100871, China
| | - Man Li
- Department of Psychology, Peking University, Beijing 100871, China
| | - Wei Du
- Department of Psychology, Peking University, Beijing 100871, China
| | - Feng Shao
- Department of Psychology, Peking University, Beijing 100871, China.
| | - Weiwen Wang
- Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China.
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15
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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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16
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Suárez LM, Cid E, Gal B, Inostroza M, Brotons-Mas JR, Gómez-Domínguez D, de la Prida LM, Solís JM. Systemic injection of kainic acid differently affects LTP magnitude depending on its epileptogenic efficiency. PLoS One 2012; 7:e48128. [PMID: 23118939 PMCID: PMC3485282 DOI: 10.1371/journal.pone.0048128] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/26/2012] [Indexed: 11/23/2022] Open
Abstract
Seizures have profound impact on synaptic function and plasticity. While kainic acid is a popular method to induce seizures and to potentially affect synaptic plasticity, it can also produce physiological-like oscillations and trigger some forms of long-term potentiation (LTP). Here, we examine whether induction of LTP is altered in hippocampal slices prepared from rats with different sensitivity to develop status epilepticus (SE) by systemic injection of kainic acid. Rats were treated with multiple low doses of kainic acid (5 mg/kg; i.p.) to develop SE in a majority of animals (72–85% rats). A group of rats were resistant to develop SE (15–28%) after several accumulated doses. Animals were subsequently tested using chronic recordings and object recognition tasks before brain slices were prepared for histological studies and to examine basic features of hippocampal synaptic function and plasticity, including input/output curves, paired-pulse facilitation and theta-burst induced LTP. Consistent with previous reports in kindling and pilocapine models, LTP was reduced in rats that developed SE after kainic acid injection. These animals exhibited signs of hippocampal sclerosis and developed spontaneous seizures. In contrast, resistant rats did not become epileptic and had no signs of cell loss and mossy fiber sprouting. In slices from resistant rats, theta-burst stimulation induced LTP of higher magnitude when compared with control and epileptic rats. Variations on LTP magnitude correlate with animals’ performance in a hippocampal-dependent spatial memory task. Our results suggest dissociable long-term effects of treatment with kainic acid on synaptic function and plasticity depending on its epileptogenic efficiency.
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Affiliation(s)
- Luz M. Suárez
- Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Instituto Cajal CSIC, Madrid, Spain
| | | | - Beatriz Gal
- Instituto Cajal CSIC, Madrid, Spain
- Universidad Europea de Madrid, Madrid, Spain
| | - Marion Inostroza
- Instituto Cajal CSIC, Madrid, Spain
- Universidad de Chile, Santiago, Chile
| | | | | | | | - José M. Solís
- Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- * E-mail: (JMS); (LMdlP)
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17
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Milton F, Butler CR, Benattayallah A, Zeman AZJ. The neural basis of autobiographical memory deficits in transient epileptic amnesia. Neuropsychologia 2012; 50:3528-41. [PMID: 23036282 DOI: 10.1016/j.neuropsychologia.2012.09.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 09/13/2012] [Accepted: 09/15/2012] [Indexed: 12/11/2022]
Abstract
Transient epileptic amnesia (TEA) is a recently recognized form of temporal lobe epilepsy which is often associated with persistent interictal impairment of autobiographical memory. We used fMRI to investigate the neural basis of this deficit. Eleven patients with TEA, who had no significant deficits on standard tests of anterograde memory, and 17 age and IQ matched healthy controls retrieved memories from across the lifespan. Both groups engaged the autobiographical memory network, but activation in patients was less extensive than in controls. Direct comparison revealed hypoactivation of regions in the right hemisphere. Specifically, patients showed reduced activation of the posterior parahippocampal gyrus (pPHG), especially for mid-life and recent memories, with decreased engagement of the right temporoparietal junction and the cerebellum. In addition, we found reduced effective connectivity in patients between the right pPHG and the right middle temporal gyrus. Our results are consistent with other evidence that TEA is a syndrome of medial temporal lobe epilepsy and indicate that it affects the function and connectivity of regions within the autobiographical memory network.
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Affiliation(s)
- Fraser Milton
- Discipline of Psychology, University of Exeter, Exeter, UK.
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18
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Milton F, Muhlert N, Pindus DM, Butler CR, Kapur N, Graham KS, Zeman AZJ. Remote memory deficits in transient epileptic amnesia. Brain 2010; 133:1368-79. [DOI: 10.1093/brain/awq055] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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19
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Mao RR, Tian M, Yang YX, Zhou QX, Xu L, Cao J. Effects of pentylenetetrazol-induced brief convulsive seizures on spatial memory and fear memory. Epilepsy Behav 2009; 15:441-4. [PMID: 19570727 DOI: 10.1016/j.yebeh.2009.05.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/27/2009] [Accepted: 05/31/2009] [Indexed: 10/20/2022]
Abstract
Previous studies have demonstrated that in the pentylenetetrazol (PTZ) kindling model, recurrent seizures either impair or have no effect on learning and memory. However, the effects of brief seizures on learning and memory remain unknown. Here, we found that a single injection of a convulsive dose of PTZ (50 mg/kg, ip) induced brief seizures in Sprague-Dawley rats. Administration of PTZ before training impaired the acquisition of spatial memory in the Morris water maze (MWM) and fear memory in contextual fear conditioning. However, the administration of PTZ immediately after training did not affect memory consolidation in either task. These findings suggest that brief seizures have different effects on acquisition and consolidation of spatial and fear memory.
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Affiliation(s)
- Rong-Rong Mao
- Key Laboratory of Animal Models and Human Disease Mechanisms and Laboratory of Learning and Memory, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, People's Republic of China
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20
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Henry LC, Goertzen CD, Lee A, Teskey GC. Repeated seizures lead to altered skilled behaviour and are associated with more highly efficacious excitatory synapses. Eur J Neurosci 2008; 27:2165-76. [PMID: 18412634 DOI: 10.1111/j.1460-9568.2008.06153.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
People with epilepsy have a high incidence of interictal behavioural problems that appear to be related to the location of their seizure focus. This study investigated a novel test of the hypotheses that repeated seizures result in behavioural deficits and altered performance during the interictal state, and that those behaviours are related to the presence of more highly efficacious excitatory synapses. We tested these hypotheses by first repeatedly eliciting seizures with electric current through indwelling electrodes in the corpus callosum at the level of the caudal forelimb area of sensorimotor neocortex in the rat. We then assessed learned skilled behaviours that primarily utilize the forelimbs on tasks that are sensitive to the functional integrity of that structure. We observed both behavioural deficits and altered kinematic performance in rats that experienced repeated neocortical seizures relative to an electrode-implanted control group. From a separate set of rats, tissue was prepared for quantification of thickness and excitatory synaptic subtypes from neocortical layer V. We observed significantly increased numbers of perforated synapses that make their connections directly onto the dendritic shaft at 3 weeks following the last seizure. Altered reaching behaviours are likely due to neural reorganization in the neocortex including more efficacious synapses.
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Affiliation(s)
- Luke C Henry
- Behavioural Neuroscience Research Group, Department of Psychology, Epilepsy and Brain Circuits Program, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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21
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Omrani A, Ghadami M, Fathi N, Tahmasian M, Fathollahi Y, Touhidi A. Naloxone improves impairment of spatial performance induced by pentylenetetrazol kindling in rats. Neuroscience 2007; 145:824-31. [DOI: 10.1016/j.neuroscience.2006.12.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 12/23/2006] [Indexed: 10/23/2022]
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22
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Leung LS, Shen B. Hippocampal CA1 kindling but not long-term potentiation disrupts spatial memory performance. Learn Mem 2006; 13:18-26. [PMID: 16418436 PMCID: PMC1360129 DOI: 10.1101/lm.66106] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Long-term synaptic enhancement in the hippocampus has been suggested to cause deficits in spatial performance. Synaptic enhancement has been reported after hippocampal kindling that induced repeated electrographic seizures or afterdischarges (ADs) and after long-term potentiation (LTP) defined as synaptic enhancement without ADs. We studied whether repeated stimulations that gave LTP or ADs resulted in spatial performance deficits on the radial arm maze (RAM) and investigated the minimal number of ADs required for such deficits. Three experimental groups were run as follows: (1) 5 hippocampal ADs in 1 d (5-AD group), (2) 10 hippocampal ADs in 2 d (10-AD group), and (3) 12 -frequency primed-burst stimulations (PBSs) in 2 d in order to induce LTP without ADs (LTP group). Each experimental group was run together with a control group during the same time period. Rats were first trained in a spatial task on a radial arm maze with four of the eight arms baited, then given control or experimental treatment, and maze performance was tested in the first week (1-4 d) and fourth week (22-25 d) after treatment. Basal dendritic population excitatory postsynaptic potentials (pEPSPs) and medial perforant path (MPP)-evoked dentate gyrus population spike and polysynaptic CA1 excitation were recorded before and after experimental and control treatment. Spatial memory errors, in particular reference memory errors, were significantly higher in the 10-AD kindled group than any other group on the first and fourth week after treatment. Spatial memory errors were not significantly different in the 5-AD and LTP groups as compared with any control groups at any time. Basal dendritic pEPSP in CA1 was enhanced for about 1 wk after 12 PBSs, 10 ADs, or 5 ADs, while the dentate gyrus population spike and CA1 polysynaptic excitation evoked by MPP was increased for up to 4 wk after 10 ADs, but not 12 PBSs. Thus, distributed alteration of multiple synaptic transmission in the entorhinal-hippocampal circuit, but not LTP at the basal dendritic synapses in CA1, may disrupt spatial performance after 10 hippocampal ADs.
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Affiliation(s)
- L Stan Leung
- Department of Physiology, The University of Western Ontario, London, Canada N6A 5C1.
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23
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Vatury O, Barg J, Slotkin TA, Yanai J. Altered localization of choline transporter sites in the mouse hippocampus after prenatal heroin exposure. Brain Res Bull 2004; 63:25-32. [PMID: 15121236 DOI: 10.1016/j.brainresbull.2003.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2003] [Revised: 11/15/2003] [Accepted: 11/30/2003] [Indexed: 10/26/2022]
Abstract
Prenatal heroin exposure disrupts hippocampal cholinergic synaptic function and related behaviors. Biochemical studies indicate an increase in the number of presynaptic high-affinity choline transporter (HACT) sites, as assessed by [3H]hemicholinium-3 (HC-3) binding. The present study was designed to assess whether this effect involves global upregulation of the transporter, or whether disruption occurs with a specific tempero-spatial distribution. Pregnant mice were given 10mg/kg per day of heroin subcutaneously on gestational days (GD) 9-18. Autoradiographic distribution of HC-3 binding sites was evaluated in the hippocampus of the offspring at postnatal days 15, 25, and 53. These results, suggestive of hippocampal "miswiring," are likely to explain the net impairment of cholinergic synaptic function after prenatal heroin exposure, despite the simultaneous upregulation of both presynaptic cholinergic activity and postsynaptic receptors. Understanding the subregional selectivity of hippocampal defects can lead to the development of strategies that may potentially enable therapeutic interventions to offset or reverse the neurobehavioral defects.
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Affiliation(s)
- Ori Vatury
- The Ross Laboratory for Studies in Neural Birth Defects, Department of Anatomy and Cell Biology, The Hebrew University-Hadassah Medical School, Box 12272, 91120 Jerusalem, Israel
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24
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Hannesson DK, Wallace AE, Pollock M, Corley S, Mohapel P, Corcoran ME. The relation between extent of dorsal hippocampal kindling and delayed-match-to-place performance in the Morris water maze. Epilepsy Res 2004; 58:145-54. [PMID: 15120745 DOI: 10.1016/j.eplepsyres.2004.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2003] [Revised: 01/30/2004] [Accepted: 01/30/2004] [Indexed: 10/26/2022]
Abstract
Dorsal hippocampal kindling impairs subsequent performance on spatial tasks. The relation between this effect and the extent of kindling achieved prior to testing has not been clearly established. Thus, the present study investigated the effects of dorsal hippocampal kindling on performance of a delayed-match-to-place (DMTP) task in the Morris water maze by assessing performance after each of series of different points in the kindling process including 1, 6, 11, and 16 afterdischarges, 1 stage 1 seizure, and 1 stage 5 seizure. We found that kindling produced a deficit that was apparent very early into kindling in terms of both direct swim (by 1 AD) and escape distance (by 6 ADs) measures but that did not clearly change in severity with further kindling. These results illustrate that kindling of even a few localized hippocampal seizures can disrupt spatial cognition and suggest that the mechanisms mediating memory disruption either do not change substantially as kindling progresses or that compensatory processes are engaged across training that mitigate any further kindling-related deteriorations in performance.
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Affiliation(s)
- D K Hannesson
- Department of Psychology, University of Regina, Regina, SK, Canada, S4S 0A2
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25
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Hannesson DK, Mohapel P, Corcoran ME. Dorsal hippocampal kindling selectively impairs spatial learning/short-term memory. Hippocampus 2002; 11:275-86. [PMID: 11769309 DOI: 10.1002/hipo.1042] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Kindling with electrical stimulation of the dorsal hippocampus has been shown to disrupt spatial task performance in rats. The present study investigated the specificity of this effect in terms of the possible contribution of nonmnemonic effects, the presence of a more general mnemonic deficit, and the involvement of learning/short-term memory and/or long-term memory processes. Rats were fully kindled with stimulation of the dorsal hippocampus and subsequently tested for acquisition, 7-day retention, and 28-day retention of a hidden platform (HP) location in the Morris water maze and an object discrimination problem in a modified water maze. To control for nonmnemonic behavioral impairments, testing on both tasks was preceded by training on visible platform control tasks. Kindling impaired acquisition of the HP location but spared performance on all other aspects of testing, indicating a specific impairment of spatial learning/short-term memory. These results suggest that epileptogenesis induced by hippocampal stimulation is indeed associated with a selective disruption of the mechanisms mediating spatial learning/short-term memory.
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Affiliation(s)
- D K Hannesson
- Department of Psychology and Neuropsychiatric Research Unit, University of Saskatchewan, Saskatoon, Canada
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26
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Dorsal hippocampal kindling produces a selective and enduring disruption of hippocampally mediated behavior. J Neurosci 2001. [PMID: 11404431 DOI: 10.1523/jneurosci.21-12-04443.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Kindling produces enduring neural changes that are subsequently manifest in enhanced susceptibility to seizure-evoking stimuli and alterations in some types of behavior. The present study investigated the effects of dorsal hippocampal (dHPC) kindling on a variety of behaviors to clarify the nature of previously reported effects on spatial task performance. Rats were kindled twice daily with dHPC stimulation until three fully generalized seizures were evoked. Beginning 7 d later and on successive days, rats were tested in an elevated plus maze, a large circular open field, an open field object exploration task, and a delayed-match-to-place (DMTP) task in a water maze to assess anxiety-related and activity-related behavior (tasks 1 and 2), object recognition memory (task 3), and spatial cognition (task 4). Kindling disrupted performance on the DMTP task in a manner that was not delay dependent and produced a mild enhancement of activity-related behaviors in the open field task but not the elevated plus maze. All other aspects of testing were spared. These findings indicate that dHPC kindling produces enduring and selective effects on behavior that are consistent with a restricted disruption of hippocampally mediated functions. Possible bases for these effects are changes in local NMDA receptor function and/or changes in local inhibition, which might alter the optimal conditions for experience-dependent induction of intrahippocampal plasticity. This preparation may be useful for studying the mechanisms of mnemonic dysfunction associated with temporal lobe epilepsy and may offer unique insights into the mechanisms underlying normal hippocampal function.
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Genkova-Papazova MG, Petkova B, Shishkova N, Lazarova-Bakarova M. Effect of the calcium channel blockers nifedipine and diltiazem on pentylenetetrazole kindling-provoked amnesia in rats. Eur Neuropsychopharmacol 2001; 11:91-6. [PMID: 11313152 DOI: 10.1016/s0924-977x(00)00120-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A large body of research supports the view that memory disturbance is an integral part of epilepsy. Deficit in various behaviour tasks has been found in rats subjected to experimental epilepsy-pentylenetetrazole (PTZ) kindling. In the present study we examined the effect of post-training administered calcium channel blockers nifedipine (10 and 40 mg/kg) and diltiazem (10 and 30 mg/kg) on amnesia induced by PTZ kindling in shuttle-box- and step-down-trained rats. Retention in nifedipine- or diltiazem-treated kindled animals was significantly improved compared to the kindled controls. The mechanisms of action of calcium antagonists studied is considered. Taken together with the data about calcium channel blocker anticonvulsive activity, the results of this study further suggest that nifedipine and diltiazem might be useful in the treatment of cognitive disorders in epileptic patients.
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Affiliation(s)
- M G Genkova-Papazova
- Laboratory of CNS Pharmacology, Institute of Physiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 23, 1113, Sofia, Bulgaria.
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28
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Sutula TP. Secondary epileptogenesis, kindling, and intractable epilepsy: a reappraisal from the perspective of neural plasticity. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2001; 45:355-86. [PMID: 11130906 DOI: 10.1016/s0074-7742(01)45019-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- T P Sutula
- Department of Neurology and Anatomy, Neurosciences Training Program, University of Wisconsin, Madison, Wisconsin, USA
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29
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Abstract
We reviewed the neural mechanisms underlying some postictal behaviors that are induced or disrupted by temporal lobe seizures in humans and animals. It is proposed that the psychomotor behaviors and automatisms induced by temporal lobe seizures are mediated by the nucleus accumbens. A non-convulsive hippocampal afterdischarge in rats induced an increase in locomotor activity, which was suppressed by the injection of dopamine D(2) receptor antagonist in the nucleus accumbens, and blocked by inactivation of the medial septum. In contrast, a convulsive hippocampal or amygdala seizure induced behavioral hypoactivity, perhaps by the spread of the seizure into the frontal cortex and opiate-mediated postictal depression. Mechanisms underlying postictal psychosis, memory disruption and other long-term behavioral alterations after temporal lobe seizures, are discussed. In conclusion, many of the changes of postictal behaviors observed after temporal lobe seizures in humans may be found in animals, and the basis of the behavioral change may be explained as a change in neural processing in the temporal lobe and the connecting subcortical structures.
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Affiliation(s)
- L S Leung
- Department of Physiology and Clinical Neurological Sciences, University of Western Ontario, Ont., N6A 5A5, London, Canada.
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30
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Rössler AS, Schröder H, Dodd RH, Chapouthier G, Grecksch G. Benzodiazepine receptor inverse agonist-induced kindling of rats alters learning and glutamate binding. Pharmacol Biochem Behav 2000; 67:169-75. [PMID: 11113497 DOI: 10.1016/s0091-3057(00)00312-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Kindling, recognized as a model of epilepsy, can be obtained by applications of repeated nonconvulsive stimulations that finally lead to generalized seizures. Epileptics often show cognitive impairments. The present work analyzed the learning performance of male Wistar rats kindled with a convulsant inverse agonist of the GABA(A)-benzodiazepine receptor complex, methyl beta-carboline-3-carboxylate (beta-CCM). This compound is also known to have an action on learning processes. It was thus interesting to verify if beta-CCM kindling had the same impairing action on learning as other kindling agents, such as pentylenetetrazol (PTZ). A two-way active-avoidance shuttle-box learning task was chosen, because a deficit was found after PTZ kindling in this learning model. On the other hand, hippocampal glutamate binding, has previously been shown to be modified by both seizures and learning. Thus, the level of glutamate binding was also measured in the present study. Results showed that fully kindled rats had poorer learning performance after the third day of test than controls or not fully kindled animals. L-[3H] glutamate binding to hippocampal membrane fractions of the fully kindled animals was significantly higher when compared with controls, whereas L-[3H] glutamate binding of not fully kindled subjects did not differ from that of controls. Neuronal plasticity changes are a possible explanation for the correlation between kindling, learning deficits, and increased glutamate binding.
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Affiliation(s)
- A S Rössler
- Hôpital Pitié-Salpêtrière, UMR 7593, CNRS, 91 Boulevard Hôpital, 75634 Cedex 13, Paris, France.
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Abstract
Kindling produces enduring changes in the brain that are evident in not only enhanced susceptibility to seizure-evoking stimuli but also alterations in non-epileptic behaviors or functions. The present review examines the effects of kindling on one class of non-epileptic functions, learning and memory, and explores the dependence of these effects on variables such as the site of kindling, extent of kindling, and interval between kindling and testing. Current research shows that kindling is capable of altering performance on a variety of tasks including those that require spatial cognition, aversive conditioning, and object-related cognition and that non-mnemonic effects are unlikely, in at least some cases, to underlie these effects. Consideration of the conditions under which these effects are observed indicates a distinct relation between specific mnemonic effects and both the site and extent of kindling. Continued characterization of the mnemonic effects of kindling should provide a theoretical framework to guide discovery of their underlying mechanisms, which, in turn, may lead to rational therapy for mnemonic dysfunction associated with epilepsy and insights into the mechanisms of learning and memory.
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Affiliation(s)
- D K Hannesson
- Department of Psychology and Psychiatry, Neuropsychiatric Research Unit, University of Saskatchewan, 103 Wiggins Road, Sask, S7N 5E4, Saskatoon, Canada
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Lamberty Y, Klitgaard H. Consequences of Pentylenetetrazole Kindling on Spatial Memory and Emotional Responding in the Rat. Epilepsy Behav 2000; 1:256-261. [PMID: 12609441 DOI: 10.1006/ebeh.2000.0085] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We investigated the consequences of pentylenetetrazole (PTZ) kindling on cognitive capacities of rats in a Morris water maze assessing spatial reference memory and in the spontaneous alternation test used as an index of working memory. The emotional consequences of PTZ kindling were also evaluated in an elevated plus maze test. Results indicated that PTZ kindled rats were not different from controls in mastering the water maze. However, PTZ kindled rats did not persist in searching the platform when evaluated at the end of learning. This suggests an altered place memory, although alternative explanations, like reduced anxiety, may be involved. Indeed, such anxiolytic activity was observed in a separate group of kindled rats evaluated in the plus maze test. No significant effect of PTZ kindling was noted in the spontaneous alternation test. These results question the generalization of previous results obtained in learning tests using electric shocks and illustrate the complexity of the PTZ model for the study of the behavioral consequences of kindling.
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Affiliation(s)
- Yves Lamberty
- UCB Pharma, Chemin du Foriest, B-1420, Braine l'Alleud, Belgium
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Genkova-Papazova MG, Petkova B, Shishkova N, Lazarova-Bakarova M. The GABA-B antagonist CGP 36742 prevent PTZ-kindling-provoked amnesia in rats. Eur Neuropsychopharmacol 2000; 10:273-8. [PMID: 10871709 DOI: 10.1016/s0924-977x(00)00082-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Deficit in active and inhibitory avoidance behaviour has been found in pentylenetetrazole (PTZ)-kindled rats. This supports the view that memory deficit is an integral part of epilepsy. In the present study we examined the effect of the GABA B antagonist CGP 36742 on memory deficit induced by PTZ-kindling in shuttle-box- and step-down-trained rats. The retention in CGP 36742-treated animals was significantly improved compared to the kindled controls. The mechanisms of action of CGP 36742 is considered. The favourable effect of the GABA B antagonist in cases of amnesia provoked by PTZ-kindling might be of interest in clinical practice.
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Affiliation(s)
- M G Genkova-Papazova
- Laboratory CNS Pharmacology, Institute of Physiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 23, 1113, Sofia, Bulgaria.
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Gilbert TH, Hannesson DK, Corcoran ME. Hippocampal kindled seizures impair spatial cognition in the Morris water maze. Epilepsy Res 2000; 38:115-25. [PMID: 10642039 DOI: 10.1016/s0920-1211(99)00064-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We investigated the effects of hippocampally kindled seizures on spatial performance of rats in the Morris water maze (MWM). Seizures were elicited with stimulation of field CA1 of dorsal hippocampus 25-45 min prior to daily testing in the water maze. One group of rats was naive to the MWM (acquisition groups), while another group received pretraining in the MWM (retention groups). These groups were further subdivided into rats that experienced non-convulsive seizures prior to daily testing and rats that experienced fully generalized convulsive seizures prior to daily testing. We found that CA1 seizures significantly disrupted water maze performance during both acquisition and retention, and the effects were similar when either non-convulsive or fully generalized convulsive seizures were evoked. Our findings are consistent with previous reports suggesting that epileptiform activity in the hippocampus acutely impairs performance in tasks sensitive to spatial learning and memory deficits and suggest that both new learning and demonstration of an established place response are susceptible to such disruption.
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Affiliation(s)
- T H Gilbert
- Department of Psychology, University of Victoria, BC, Canada.
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35
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Moser EI, Moser MB. Is learning blocked by saturation of synaptic weights in the hippocampus? Neurosci Biobehav Rev 1999; 23:661-72. [PMID: 10392658 DOI: 10.1016/s0149-7634(98)00060-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Long-term potentiation (LTP) has become a leading candidate mechanism for memory formation. The proposed link between LTP and memory rests primarily on a single type of behavioural evidence: disruption of learning by interventions that block critical steps in the induction of LTP. As such blockade may disrupt non-mnemonic functions also, the LTP-learning question should be approached with multiple strategies. One alternative approach is to determine whether hippocampus-dependent learning is blocked by saturation of hippocampal LTP before training. Early investigations found that spatial learning was impaired after cumulative LTP in dentate perforant-path synapses. Several groups failed to replicate these findings, but it is now clear that hippocampus-dependent spatial learning is disrupted only if LTP is saturated throughout the terminal field of the tetanized pathway. Moreover, to prevent compensatory modifications in the hippocampal network, a massed tetanization and training protocol may be required. The blockade of learning by repetition of the very same stimulus that induces LTP suggests that LTP-like modifications are necessary for memory encoding in the hippocampus.
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Affiliation(s)
- E I Moser
- Department of Psychology, Norwegian University of Science and Technology, Trondheim.
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Cammisuli S, Murphy MP, Ikeda-Douglas CJ, Balkissoon V, Holsinger RM, Head E, Michael M, Racine RJ, Milgram NW. Effects of extended electrical kindling on exploratory behavior and spatial learning. Behav Brain Res 1997; 89:179-90. [PMID: 9475625 DOI: 10.1016/s0166-4328(97)00059-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Short-term electrical kindling, a widely used experimental model of epilepsy, appears to have little effect on behavior. The effects of extended kindling are largely unknown. Rats implanted with kindling electrodes in amygdala (AM) or perforant path (PP) received 300 kindling trials over approximately 7 months, and were tested in the Morris watermaze after a 7-10 day recovery period. Kindled animals were impaired during the initial training on hidden-platform acquisition, but not in retention of platform location. No deficits were found in acquiring a new hidden-platform location, latency to reach a visible-platform, or in swim speed. Open-field activity showed a sustained increase when tested during kindling, but only a transient increase when tested following suspension of kindling. Similar results were obtained for both AM and PP kindled animals. Hence, long-term kindling of both of these sites produced behavioral changes that were transient in nature. Further, these results also indicate that propagation of seizure activity from remote sites can alter hippocampally-mediated or related behavior.
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Affiliation(s)
- S Cammisuli
- Department of Psychology, Scarborough Campus, University of Toronto, Ontario, Canada
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