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Jiang H, Zhang S. Therapeutic effect of acute and chronic use of different doses of vitamin D3 on seizure responses and cognitive impairments induced by pentylenetetrazole in immature male rats. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2022; 25:84-95. [PMID: 35656438 PMCID: PMC9118278 DOI: 10.22038/ijbms.2021.60123.13328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 12/15/2021] [Indexed: 12/18/2022]
Abstract
Objective(s): This study aimed to evaluate the effects of acute and chronic intake of different doses of vitamin D3 on seizure responses and cognitive impairment induced by pentylenetetrazole (PTZ) in immature male rats. Materials and Methods: Sixty-six immature male NMRI rats were divided into control (10), epileptic (10), and treatment groups (46). The stage 5 latency (S5L) and stage 5 duration (S5D) were assessed along with the shuttle box test. Levels of antioxidant enzymes and inflammatory factors along with genes involved in inflammation, oxidative damage, apoptosis, and mTORc1 were measured in the hippocampus tissue of the brain of controlled and treated rats. Serum levels of parathyroid hormone (PTH), vitamin D, calcium, and phosphorus were also assessed. Results: The results showed that the ability to learn, memory consolidation, and memory retention in epileptic rats were reduced. In addition, S5D increased and S5L decreased in epileptic rats, while being effectively ameliorated by chronic and acute vitamin D intake. The results showed that vitamin D in different doses acutely and chronically decreased the levels of oxidative and inflammatory biomarkers in hippocampus tissue and inhibited the expression of genes involved in inflammation, oxidative damage, apoptosis, and mTORc1 in the hippocampus tissue of epileptic rats. Conclusion: The results showed that vitamin D in different doses acutely and chronically could improve cognitive impairments and convulsive responses in epileptic rats by improving neurotransmission, inflammation, apoptosis, and oxidative damage.
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Affiliation(s)
- Hong Jiang
- Department of Pediatric, Weinan Maternal and Child Health Hospital, Weinan, 714000, China
| | - Suying Zhang
- Department of Child Health, Weinan Central Hospital, Weinan, 714000, China
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The Kainic Acid Models of Temporal Lobe Epilepsy. eNeuro 2021; 8:ENEURO.0337-20.2021. [PMID: 33658312 PMCID: PMC8174050 DOI: 10.1523/eneuro.0337-20.2021] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/14/2021] [Accepted: 01/24/2021] [Indexed: 12/14/2022] Open
Abstract
Experimental models of epilepsy are useful to identify potential mechanisms of epileptogenesis, seizure genesis, comorbidities, and treatment efficacy. The kainic acid (KA) model is one of the most commonly used. Several modes of administration of KA exist, each producing different effects in a strain-, species-, gender-, and age-dependent manner. In this review, we discuss the advantages and limitations of the various forms of KA administration (systemic, intrahippocampal, and intranasal), as well as the histologic, electrophysiological, and behavioral outcomes in different strains and species. We attempt a personal perspective and discuss areas where work is needed. The diversity of KA models and their outcomes offers researchers a rich palette of phenotypes, which may be relevant to specific traits found in patients with temporal lobe epilepsy.
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Khajei S, Mirnajafi-Zadeh J, Sheibani V, Ahmadi-Zeidabadi M, Masoumi-Ardakani Y, Rajizadeh MA, Esmaeilpour K. Electromagnetic field protects against cognitive and synaptic plasticity impairment induced by electrical kindling in rats. Brain Res Bull 2021; 171:75-83. [PMID: 33753209 DOI: 10.1016/j.brainresbull.2021.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/10/2021] [Accepted: 03/16/2021] [Indexed: 01/10/2023]
Abstract
Kindling results in abnormal synaptic potentiation and significant impairment in learning and memory. Electromagnetic field (EMF) effects on learning and memory in kindled animals and its effects on hippocampal neural activity are largely unknown. In the current study, the effects of EMF on learning and memory, as well as hippocampal synaptic plasticity, in kindled rats were investigated. EMF (10 mT; 100 Hz) was applied to fully kindled animals one hour/day for a period of one week. The behavioral and electrophysiological studies were performed 24 h following the EMF application. The kindled rats showed spatial learning deficits during the training phase of the Morris water maze (MWM) test. Moreover, there were increments in escape latency and path length compared to the sham group. The kindled rats spent less time in the target-quadrant probe test, indicating spatial memory impairment. Applying EMF to the KEMF group (kindling + EMF) restored learning and memory, and decreased escape latency and path length significantly compared to the kindled group. EMF alone had no significant effects on the learning and memory parameters. Based on the open field (OF) test results, EMF alone in the EMF group, but not in the kindled or the KEMF groups, decreased the total traveled distance and increased the spent time in the peripheral zone, compared to the sham group. Based on electrophysiological results, applying EMF in the KEMF group returned the ability of synaptic potentiation to the hippocampal CA1 area and high-frequency stimulation induced long-term potentiation (LTP). Accordingly, EMF can be considered a potential therapy for seizure-induced deficits in learning and memory.
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Affiliation(s)
- Sina Khajei
- 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
| | - Vahid Sheibani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Meysam Ahmadi-Zeidabadi
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Yaser Masoumi-Ardakani
- Physiology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Amin Rajizadeh
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Khadijeh Esmaeilpour
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran.
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Tahmasebi S, Oryan S, Mohajerani HR, Akbari N, Palizvan MR. Probiotics and Nigella sativa extract supplementation improved behavioral and electrophysiological effects of PTZ-induced chemical kindling in rats. Epilepsy Behav 2020; 104:106897. [PMID: 32028126 DOI: 10.1016/j.yebeh.2019.106897] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/26/2019] [Accepted: 12/30/2019] [Indexed: 12/15/2022]
Abstract
INTRODUCTION Epilepsy is a most common neurological disorder that has negative effects on cognition. In the present study, we investigated the protective effect of Nigella sativa (NS) and probiotics on seizure activity, cognitive performance, and synaptic plasticity in pentylenetetrazole (PTZ) kindling model of epilepsy. METHODS One hundred and forty-four rats were divided into 2 experiments: In experiment 1, animals were grouped and treated as follows: 1) control (PTZ + saline), 2) NS treatment, 3) probiotic treatment, and 4) NS and probiotic treatment. Six weeks after the treatment, PTZ kindling were performed, and 48 h after kindling, spatial learning and memory were measured in Morris water maze (MWM) test. Animals in experiment 2 received the same treatment as experiment 1: in control nonkindled groups, control animals were treated with probiotics, NS, and probiotics + NS. Six weeks after the treatment, PTZ kindling were performed, and 48 h after kindling, field potentials were recorded from the dentate gyrus area of the hippocampus; synaptic transmission and long-term potentiation (LTP) was measured. RESULTS The results showed that the probiotic and NS supplementation significantly reduces kindling development so that animals in PTZ + NS + probiotic did not show full kindling. In MWM test, the escape latency and traveled path in the kindled group were significantly higher than the control group. In PTZ + NS + probiotics, these parameters were significantly lower than those in the PTZ + saline group. Adding probiotic and NS supplementation significantly reduced population spike (PS)-LTP as compared with the PTZ + saline group. CONCLUSION Probiotic and NS supplementation have some protection against seizure, seizure-induced cognitive impairment, and hippocampal LTP in kindled rats.
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Affiliation(s)
- Saeed Tahmasebi
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Shahrbanoo Oryan
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran; Department of Biology, Faculty of Science, Kharazmy University, Tehran, Iran.
| | | | - Neda Akbari
- Department of Microbiology, Faculty of Science, Islamic Azad University, Arak, Iran
| | - Mohammad Reza Palizvan
- Department of Physiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
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Khodamoradi M, Asadi-Shekaari M, Esmaeili-Mahani S, Sharififar F, Sheibani V. Effects of Hydroalcoholic Extract of Soy on Learning, Memory and Synaptic Plasticity Deficits Induced by Seizure in Ovariectomized Rats. Basic Clin Neurosci 2017; 8:395-403. [PMID: 29167726 PMCID: PMC5691171 DOI: 10.18869/nirp.bcn.8.5.395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Introduction: Previous studies have shown that seizure can induce cognitive impairment. On the other hand, soy phytoestrogens, which are mainly found in soybean (Glycine max (L.) Merr.), have beneficial effects on the nervous system. However, little is known about their probable effects on seizure. The present study aimed to examine the probable effects of soy extract, containing the phytoestrogen genistein on seizure-induced cognitive and synaptic plasticity impairment in Ovariectomized (OVX) rats. Methods: Rats were ovariectomized, implanted with guide cannula and then divided into 5 groups (n=7–8 in each group): PBS, KA, Saline-KA, Higher Dose Soy (HDS-KA), and Lower Dose Soy (LDS-KA) groups. Animals of the HDS-KA and LDS-KA groups received intraperitoneal administration of soy extract (20 and 2 mg/kg, respectively) and the Saline-KA group received normal saline once a day for 4 days. Sixty minutes after the last injection, Kainic Acid (KA) or PBS was injected into the left lateral ventricle via pre-implanted guide cannula to induce generalized seizures. The Morris water maze task and in vivo field potential recordings were conducted 7 days later. Results: Soy extract at both doses significantly improved learning impairment and at the higher dose (20 mg/kg) significantly prevented seizure-induced spatial memory impairment and deficit of long-term potentiation in the hippocampus. Conclusion: The soy extract containing the phytoestrogen genistein may have beneficial effects on memory deficit induced by seizure in OVX rats and this effect is accompanied by a beneficial effect on synaptic plasticity.
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Affiliation(s)
- Mehdi Khodamoradi
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Majid Asadi-Shekaari
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | | | - Fariba Sharififar
- Herbal and Traditional Medicines Research Center, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Sheibani
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
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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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Ahmadi M, Dufour JP, Seifritz E, Mirnajafi-Zadeh J, Saab BJ. The PTZ kindling mouse model of epilepsy exhibits exploratory drive deficits and aberrant activity amongst VTA dopamine neurons in both familiar and novel space. Behav Brain Res 2017; 330:1-7. [PMID: 28506618 DOI: 10.1016/j.bbr.2017.05.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/04/2017] [Accepted: 05/10/2017] [Indexed: 01/12/2023]
Abstract
Recurrent seizures that define epilepsy are often accompanied by psychosocial problems and cognitive deficits with incompletely understood aetiology. We therefore used the pentylenetetrazol (PTZ) kindling model of epilepsy in mice to examine potential seizure-associated neuropathologies, focusing on motivation, memory and novel-environment-induced activation of midbrain dopaminergic neurons. In addition to recurrent seizures, we found that PTZ kindling led to a strong suppression of novelty-driven exploration while largely sparing fear-driven exploration. The deficits in exploratory drive may be relevant for other cognitive impairments since reduced unassisted rearing in a learning arena correlated with poorer spatial memory of object location. Using c-Fos immunofluorescence as a marker of neuronal activity, we observed that dopamine neurons within the ventral tegmental area (VTA) of PTZ kindled mice demonstrate hyperactivity at baseline and hypoactivity in response to a novel environment compared to saline-injected cagemate controls. These data extend previous findings of PTZ kindling-mediated disruptions of hippocampal processes important for novel environment recognition and learning by demonstrating PTZ kindling also induces motivational deficits that are associated with reduced stimulus-evoked activation of VTA dopamine neurons. More broadly, these data help understand the aetiology of complex behavioural changes in the PTZ kindling model, and may assist in the development of superior diagnoses and treatments for epilepsy.
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Affiliation(s)
- Mahboubeh Ahmadi
- Preclinical Laboratory for Translational Research into Affective Disorders, DPPP, Psychiatric Hospital, University of Zurich, August-Forel-Strasse 7, CH-8008 Zurich, Switzerland; Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, PO Box: 14115-331, 1411713116, Tehran, Iran
| | - Jean-Philippe Dufour
- Preclinical Laboratory for Translational Research into Affective Disorders, DPPP, Psychiatric Hospital, University of Zurich, August-Forel-Strasse 7, CH-8008 Zurich, Switzerland; Faculty of Medicine, University of Zurich, Switzerland
| | - Erich Seifritz
- Preclinical Laboratory for Translational Research into Affective Disorders, DPPP, Psychiatric Hospital, University of Zurich, August-Forel-Strasse 7, CH-8008 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Pesychosomatics (DPPP), Psychiatric Hospital, Universit of Zurich, Lengstrasse 31, CH-8032 Zurich, Switzerland
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, PO Box: 14115-331, 1411713116, Tehran, Iran.
| | - Bechara J Saab
- Preclinical Laboratory for Translational Research into Affective Disorders, DPPP, Psychiatric Hospital, University of Zurich, August-Forel-Strasse 7, CH-8008 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Pesychosomatics (DPPP), Psychiatric Hospital, Universit of Zurich, Lengstrasse 31, CH-8032 Zurich, Switzerland.
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Abstract
Previous studies have shown that the neuregulin 1 (NRG1)-ErbB4 signaling pathway may regulate the excitability of fast-spiking neurons in the frontal cortex and participate in primary epilepsy pathogenesis. However, the exact roles and mechanism for NRG1/ErbB4 in human symptomatic epilepsy are still unclear. Using fresh human symptomatic epilepsy tissues, we found that the protein levels of NRG1 and ErbB4 were significantly increased in the temporal cortex. In addition, NRG1-ErbB4 signaling suppressed phosphorylation of GluN2B at position 1472 by Src kinase, and decreased levels of phosphorylation level of GluN2B and Src were detected in human symptomatic epilepsy tissues. Our study revealed a critical role of the NRG1-ErbB4 signaling pathway in symptomatic epilepsy, which is different from that in primary epilepsy, and we propose that the NRG1-ErbB4 signaling may act as a homeostasis modulator that protects the brain from aggravation of epileptiform activity.
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Khodamoradi M, Asadi-Shekaari M, Esmaeili-Mahani S, Esmaeilpour K, Sheibani V. Effects of genistein on cognitive dysfunction and hippocampal synaptic plasticity impairment in an ovariectomized rat kainic acid model of seizure. Eur J Pharmacol 2016; 786:1-9. [DOI: 10.1016/j.ejphar.2016.05.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 04/21/2016] [Accepted: 05/23/2016] [Indexed: 11/24/2022]
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Prediction of seizure incidence probability in PTZ model of kindling through spatial learning ability in male and female rats. Physiol Behav 2016; 161:47-52. [DOI: 10.1016/j.physbeh.2016.04.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 04/04/2016] [Accepted: 04/07/2016] [Indexed: 11/18/2022]
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Yang H, Guo R, Wu J, Peng Y, Xie D, Zheng W, Huang X, Liu D, Liu W, Huang L, Song Z. The Antiepileptic Effect of the Glycolytic Inhibitor 2-Deoxy-d-Glucose is Mediated by Upregulation of KATP Channel Subunits Kir6.1 and Kir6.2. Neurochem Res 2013; 38:677-85. [DOI: 10.1007/s11064-012-0958-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 12/10/2012] [Accepted: 12/19/2012] [Indexed: 01/20/2023]
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Time-dependent changes in learning ability and induction of long-term potentiation in the lithium-pilocarpine-induced epileptic mouse model. Epilepsy Behav 2010; 17:448-54. [PMID: 20332069 DOI: 10.1016/j.yebeh.2010.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/12/2010] [Accepted: 02/13/2010] [Indexed: 11/23/2022]
Abstract
To explore the mechanism underlying the development of learning deficits in patients with epilepsy, we generated a mouse model for temporal lobe epilepsy by intraperitoneally injecting mice with pilocarpine with lithium chloride, and investigated time-dependent changes in both contextual fear memory of those model mice and long-term potentiation (LTP) in hippocampal CA1 neurons 1 day, 2 weeks, and 6 weeks after the onset of status epilepticus (SE). Fear memory formation did not change 1 day and 2 weeks after the onset of SE, but was significantly reduced after 6 weeks. Induction of LTP was enhanced 1 day after the onset of SE, but returned to the normal level 2 weeks later, and was almost completely attenuated after 6 weeks. The enhancement of LTP was accompanied by an increase in output responses of excitatory postsynaptic potentials, whereas suppression of LTP was accompanied by alteration of the ratio of paired pulse facilitation. These results indicate that time-dependent changes of LTP induction have a causal role in the development of learning deficits of epilepsy patients.
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Nagaraja RY, Becker A, Reymann KG, Balschun D. Repeated administration of group I mGluR antagonists prevents seizure-induced long-term aberrations in hippocampal synaptic plasticity. Neuropharmacology 2005; 49 Suppl 1:179-87. [PMID: 16009386 DOI: 10.1016/j.neuropharm.2005.05.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 04/28/2005] [Accepted: 05/09/2005] [Indexed: 10/25/2022]
Abstract
Kindling induced by repeated application of the convulsant pentylenetetrazole (PTZ) is a validated model of epilepsy and epilepsy-related neuromorphological, neurophysiological and behavioural alterations. In this study, we examined whether kindling-induced long-term aberrations in hippocampal synaptic plasticity can be prevented by application of group I mGluR antagonists. Kindling resulted in a higher magnitude of long-term potentiation (LTP) induced by a strong high-frequency stimulation in the hippocampal CA1 region in vitro. When the specific mGluR1 antagonist LY 367385 (0.40 microMol) or the specific mGluR5 inhibitor MPEP (0.06 microMol) were given 30 min prior to PTZ, this kindling-induced enhancement of LTP was almost completely prevented. In addition, application of MPEP led to an impaired maintenance of population spike LTP in kindled animals. LY 367385 applied to unkindled control animals caused a reduction of the initial magnitude of population spike LTP. MPEP, in contrast, left the initial magnitude untouched but resulted in a faster decay of potentiation. A single administration of LY 367385 (200 microM) and MPEP (50 microM), respectively, directly into the bath had almost no effect. Our data suggest that the long-lasting aberrations of hippocampal synaptic plasticity induced by the repeated occurrence of generalized epileptic seizures ultimately require a concurrent operation of mGluR1 and mGluR5.
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Affiliation(s)
- Raghavendra Y Nagaraja
- Otto-von-Guericke University, Faculty of Medicine, Institute of Pharmacology and Toxicology, Leipziger Strasse 44, 39120 Magdeburg, Germany
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Palizvan MR, Fathollahi Y, Semnanian S. Epileptogenic insult causes a shift in the form of long-term potentiation expression. Neuroscience 2005; 134:415-23. [PMID: 15961249 DOI: 10.1016/j.neuroscience.2005.04.016] [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: 01/10/2005] [Revised: 03/13/2005] [Accepted: 04/16/2005] [Indexed: 11/24/2022]
Abstract
The relationship between epilepsy, modeled here by pentylenetetrazol kindling, and learning deficits, modeled here by long-term potentiation (LTP), was studied. The field excitatory postsynaptic potentials and population spikes (PS) were recorded from strata radiatum and pyramidale, respectively, in urethane-anesthetized rat dorsal hippocampus CA1 area upon stimulation of Schaffer collaterals. To induce LTP, a 100 Hz primed-burst stimulation protocol was used. Experiments were carried out at approximately 30 days after the last pentylenetetrazol dose. The effects of voltage dependent calcium channel blocker verapamil and N-methyl-D-aspartate receptor antagonist MK-801 on LTP expression were examined. Tetanic stimulation elicited both field excitatory postsynaptic potential LTP and PS LTP in control animals, and LTP-induction of the PS in control animals was attenuated by MK-801, but not by verapamil. By contrast, kindled rats showed LTP of the PS only. MK-801 reduced the extent of potentiation of PS amplitude and verapamil inhibited the PS amplitude potentiation, completely. The results suggest that seizure induction modifies mechanisms underlying LTP induction and causes a shift in the form of LTP expression. The pentylenetetrazol-kindling-induced increase in PS LTP is sensitive to verapamil and not to MK-801 and therefore primarily dependent on activation of voltage dependent calcium channels rather N-methyl-D-aspartate receptors. Kindling may lead to a shift in synaptic plasticity thresholds much like the shift that occurs during aging, and such alterations may contribute to deficits in learning and memory.
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Affiliation(s)
- M R Palizvan
- Department of Physiology, School of Medical Sciences, Tarbiat Modarres University, P.O. Box 14115-111, Tehran, Iran
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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: 603] [Impact Index Per Article: 30.2] [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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