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Song H, Mah B, Sun Y, Aloysius N, Bai Y, Zhang L. Development of spontaneous recurrent seizures accompanied with increased rates of interictal spikes and decreased hippocampal delta and theta activities following extended kindling in mice. Exp Neurol 2024; 379:114860. [PMID: 38876195 DOI: 10.1016/j.expneurol.2024.114860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/30/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024]
Abstract
Interictal epileptiform discharges refer to aberrant brain electrographic signals between seizures and feature intermittent interictal spikes (ISs), sharp waves, and/or abnormal rhythms. Recognition of these epileptiform activities by electroencephalographic (EEG) examinations greatly aids epilepsy diagnosis and localization of the seizure onset zone. ISs are a major form of interictal epileptiform discharges recognized in animal models of epilepsy. Progressive changes in IS waveforms, IS rates, and/or associated fast ripple oscillations have been shown to precede the development of spontaneous recurrent seizures (SRS) in various animal models. IS expressions in the kindling model of epilepsy have been demonstrated but IS changes during the course of SRS development in extended kindled animals remain to be detailed. We hence addressed this issue using a mouse model of kindling-induced SRS. Adult C57 black mice received twice daily hippocampal stimulations until SRS occurrence, with 24-h EEG monitoring performed following 50, 80, and ≥ 100 stimulations and after observation of SRS. In the stimulated hippocampus, increases in spontaneous ISs rates, but not in IS waveforms nor IS-associated fast ripples, along with decreased frequencies of hippocampal delta and theta rhythms, were observed before SRS onset. Comparable increases in IS rates were further observed in the unstimulated hippocampus, piriform cortex, and entorhinal cortex, but not in the unstimulated parietal cortex and dorsomedial thalamus. These data provide original evidence suggesting that increases in hippocampal IS rates, together with reductions in hippocampal delta and theta rhythms are closely associated with development of SRS in a rodent kindling model.
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Affiliation(s)
- Hongmei Song
- Departments of Neurosurgery, India; Krembil Research Institute, University Health Network, Canada.
| | - Bryan Mah
- Krembil Research Institute, University Health Network, Canada
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Canada
| | - Nancy Aloysius
- Krembil Research Institute, University Health Network, Canada
| | - Yang Bai
- Neuro-Oncology the First Hospital of Jilin University, China.
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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Cardiovascular toxin-induced hyperglycemic and hypoarousal pathology-associated cognitive impairment: an in silico and in vivo validation. CARDIOLOGY PLUS 2022. [DOI: 10.1097/cp9.0000000000000030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Zahra A, Sun Y, Aloysius N, Zhang L. Convulsive behaviors of spontaneous recurrent seizures in a mouse model of extended hippocampal kindling. Front Behav Neurosci 2022; 16:1076718. [PMID: 36620863 PMCID: PMC9816810 DOI: 10.3389/fnbeh.2022.1076718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Growing studies indicate that vigilance states and circadian rhythms can influence seizure occurrence in patients with epilepsy and rodent models of epilepsy. Electrical kindling, referred to brief, repeated stimulations of a limbic structure, is a commonly used model of temporal lobe epilepsy. Kindling via the classic protocol lasting a few weeks does not generally induce spontaneous recurrent seizures (SRS), but extended kindling that applies over the course of a few months has shown to induce SRS in several animal species. Kindling-induced SRS in monkeys and cats were observed mainly during resting wakefulness or sleep, but the behavioral activities associated with SRS in rodent models of extended kindling remain unknown. We aimed to add information in this area using a mouse model of extended hippocampal kindling. Middle-aged C57 black mice experienced ≥80 hippocampal stimulations (delivered twice daily) and then underwent continuous 24 h electroencephalography (EEG)-video monitoring for SRS detection. SRS were recognized by EEG discharges and associated motor seizures. The five stages of the modified Racine scale for mice were used to score motor seizure severities. Seizure-preceding behaviors were assessed in a 3 min period prior to seizure onset and categorized as active and inactive. Three main observations emerged from the present analysis. (1) SRS were found to predominantly manifest as generalized (stage 3-5) motor seizures in association with tail erection or Straub tail. (2) SRS occurrences were not significantly altered by the light on/off cycle. (3) Generalized (stage 3-5) motor seizures were mainly preceded by inactive behaviors such as immobility, standing still, or apparent sleep without evident volitional movement. Considering deeper subcortical structures implicated in genesis of tail erection in other seizure models, we postulate that genesis of generalized motor seizures in extended kindled mice may involve deeper subcortical structures. Our present data together with previous findings from post-status epilepticus models support the notion that ambient cage behaviors are strong influencing factors of SRS occurrence in rodent models of temporal lobe epilepsy.
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Affiliation(s)
- Anya Zahra
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Nancy Aloysius
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada,Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada,*Correspondence: Liang Zhang,
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Contreras-García IJ, Cárdenas-Rodríguez N, Romo-Mancillas A, Bandala C, Zamudio SR, Gómez-Manzo S, Hernández-Ochoa B, Mendoza-Torreblanca JG, Pichardo-Macías LA. Levetiracetam Mechanisms of Action: From Molecules to Systems. Pharmaceuticals (Basel) 2022; 15:ph15040475. [PMID: 35455472 PMCID: PMC9030752 DOI: 10.3390/ph15040475] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 11/16/2022] Open
Abstract
Epilepsy is a chronic disease that affects millions of people worldwide. Antiepileptic drugs (AEDs) are used to control seizures. Even though parts of their mechanisms of action are known, there are still components that need to be studied. Therefore, the search for novel drugs, new molecular targets, and a better understanding of the mechanisms of action of existing drugs is still crucial. Levetiracetam (LEV) is an AED that has been shown to be effective in seizure control and is well-tolerable, with a novel mechanism of action through an interaction with the synaptic vesicle protein 2A (SV2A). Moreover, LEV has other molecular targets that involve calcium homeostasis, the GABAergic system, and AMPA receptors among others, that might be integrated into a single mechanism of action that could explain the antiepileptogenic, anti-inflammatory, neuroprotective, and antioxidant properties of LEV. This puts it as a possible multitarget drug with clinical applications other than for epilepsy. According to the above, the objective of this work was to carry out a comprehensive and integrative review of LEV in relation to its clinical uses, structural properties, therapeutical targets, and different molecular, genetic, and systemic action mechanisms in order to consider LEV as a candidate for drug repurposing.
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Affiliation(s)
| | - Noemí Cárdenas-Rodríguez
- Laboratorio de Neurociencias, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Ciudad de México 04530, Mexico;
| | - Antonio Romo-Mancillas
- Laboratorio de Diseño Asistido por Computadora y Síntesis de Fármacos, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico;
| | - Cindy Bandala
- Neurociencia Básica, Instituto Nacional de Rehabilitación LGII, Secretaría de Salud, Ciudad de México 14389, Mexico;
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico
| | - Sergio R. Zamudio
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 07738, Mexico;
| | - Saúl Gómez-Manzo
- Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de México 04530, Mexico;
| | - Beatriz Hernández-Ochoa
- Laboratorio de Inmunoquímica, Hospital Infantil de México Federico Gómez, Secretaría de Salud, Ciudad de México 06720, Mexico;
| | - Julieta Griselda Mendoza-Torreblanca
- Laboratorio de Neurociencias, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Ciudad de México 04530, Mexico;
- Correspondence: (J.G.M.-T.); (L.A.P.-M.); Tel.: +52-55-1084-0900 (ext. 1441) (J.G.M.-T.)
| | - Luz Adriana Pichardo-Macías
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 07738, Mexico;
- Correspondence: (J.G.M.-T.); (L.A.P.-M.); Tel.: +52-55-1084-0900 (ext. 1441) (J.G.M.-T.)
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Custodio V, Acosta J, Rubio C, Hernández L, Brito J, Taddei E. Accurate Neurosurgery for the Establishment of the Electric Kindling Model of Epilepsy in Mice. J INVEST SURG 2022; 35:1253-1262. [DOI: 10.1080/08941939.2022.2032488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Verónica Custodio
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía, México, México
| | - Jorge Acosta
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía, México, México
| | - Carmen Rubio
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía, México, México
| | - Leonardo Hernández
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía, México, México
| | - Javier Brito
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía, México, México
| | - Elisa Taddei
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía, México, México
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Nandini HS, Krishna KL, Apattira C. Combination of Ocimum sanctum extract and Levetiracetam ameliorates cognitive dysfunction and hippocampal architecture in rat model of Alzheimer's disease. J Chem Neuroanat 2021; 120:102069. [PMID: 34973350 DOI: 10.1016/j.jchemneu.2021.102069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/25/2021] [Accepted: 12/26/2021] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease which affects more than 40 million people worldwide with progressive loss of memory and cognitive functions. It is reported, persistent AD is also one of the main causes of epilepsy in elders and comorbidity of both these will contribute to worsening the health status of AD patients. Recently, herbal plants with potent neuroprotective and antioxidant properties were used for increasing the quality of life in neurodegenerative disease patients. The present study was conceptualized to access the protective effect of Ocimum sanctum extract (OSE) and Levetiracetam (LEV) and their combination (OSE+LEV) against AD and epilepsy associated with AD in the rat AD model. AD was induced in aged male Wistar albino rats with Amyloid-β (Aβ) by intracerebroventricular administration. The results reveal, treatment with OSE, LEV and OSE+LEV significantly reversed the memory impairment, increases the BDNF expressions and decreases AChE activity in Aβ induced AD animals. Expression of A-β and p-tau in the hippocampus was significantly reduced in treatment group when compared to the control animals. Treatment with OSE and OSE+LEV also restored the hippocampal architecture by ameliorating the neuronal count in CA1, CA3 and DG regions. It also observed that treatment has decreased the excitoneurotoxicity evidenced by decreased glutamate and increased GABA levels and thus provided protection against epilepsy. Treatment groups also exhibited a potent antioxidant activity when tested endogenous antioxidant enzymes SOD, GSH and LPO in the brain hippocampus. Our findings provide evidence for use of OSE, LEV and OSE+LEV against AD and epilepsy associated with AD in Aβ induced AD animal model. However, further clinical studies are required to prove the use of OSE, LEV and OSE+LEV in the management of AD and AD-associated epilepsy in human volunteers.
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Affiliation(s)
- H S Nandini
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagara, Mysuru 570015, Karnataka, India.
| | - K L Krishna
- Department of Pharmacology, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Sri Shivarathreeshwara Nagara, Mysuru 570015, Karnataka, India.
| | - Chinnappa Apattira
- Centre for Excellence in Molecular Biology and Regenerative Medicine (CEMR, DST-FIST Supported Center), Department of Biochemistry (DST-FIST Supported Department), JSS Medical College, JSS Academy of Higher Education & Research, Mysuru 570015, India.
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Liu H, Zhang L. Clustering of Spontaneous Recurrent Seizures in a Mouse Model of Extended Hippocampal Kindling. Front Neurol 2021; 12:738986. [PMID: 34899563 PMCID: PMC8654732 DOI: 10.3389/fneur.2021.738986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/05/2021] [Indexed: 02/03/2023] Open
Abstract
Acute repetitive seizures or seizure clusters are common in epileptic patients. Seizure clusters are associated with a high risk of developing status epilepticus and increased morbidity and mortality. Seizure clusters are also recognizable in spontaneous recurrent seizures (SRS) that occur in animal models of epilepsy. The electrical kindling of a limbic structure is a commonly used model of temporal lobe epilepsy. Although classic kindling over the course of a few weeks does not generally induce SRS, extended kindling over the course of a few months can induce SRS in several animal species. SRS in kindled cats often occur in clusters, but the existence of seizure clusters in rodent models of extended kindling remains to be demonstrated. We explored the existence of seizure clusters in mice following extended hippocampal kindling. Adult male mice (C57BL/6) experienced twice daily hippocampal stimulations and underwent continuous 24-hour electroencephalogram (EEG)-video monitoring after ≥80 stimulations. SRS events were recognized by EEG discharges and associated motor seizures. Seizure clusters, defined as ≥4 seizures per cluster and intra-cluster inter-seizure intervals ≤ 120 min, were observed in 19 of the 20 kindled mice. Individual mice showed variable seizure clusters in terms of cluster incidence and circadian-like expression patterns. For clusters consisting of 4-7 seizures and intra-seizure intervals ≤ 20 min, no consistent changes in inter-seizure intervals, EEG discharge duration, or motor seizure severity scores were observed approaching cluster termination. These results suggested that seizure clustering represents a prominent feature of SRS in hippocampal kindled mice. We speculate that, despite experimental limitations and confounding factors, systemic homeostatic mechanisms that have yet to be explored may play an important role in governing the occurrence and termination of seizure clusters.
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Affiliation(s)
- Haiyu Liu
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
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Iizumi M, Oota-Ishigaki A, Yamashita M, Hayashi T. Reduced Effect of Anticonvulsants on AMPA Receptor Palmitoylation-Deficient Mice. Front Pharmacol 2021; 12:711737. [PMID: 34483921 PMCID: PMC8416418 DOI: 10.3389/fphar.2021.711737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 08/05/2021] [Indexed: 12/29/2022] Open
Abstract
AMPA receptors are responsible for fast excitatory synaptic transmission in the mammalian brain. Post-translational protein S-palmitoylation of AMPA receptor subunits GluA1-4 reversibly regulates synaptic AMPA receptor expression, resulting in long-lasting changes in excitatory synaptic strengths. Our previous studies have shown that GluA1 C-terminal palmitoylation-deficient (GluA1C811S) mice exhibited hyperexcitability in the cerebrum and elevated seizure susceptibility without affecting brain structure or basal synaptic transmission. Moreover, some inhibitory GABAergic synapses-targeting anticonvulsants, such as valproic acid, phenobarbital, and diazepam, had less effect on these AMPA receptor palmitoylation-deficient mutant mice. This work explores pharmacological effect of voltage-gated ion channel-targeted anticonvulsants, phenytoin and trimethadione, on GluA1C811S mice. Similar to GABAergic synapses-targeting anticonvulsants, anticonvulsive effects were also reduced for both sodium channel- and calcium channel-blocking anticonvulsants, which suppress excess excitation. These data strongly suggest that the GluA1C811S mice generally underlie the excessive excitability in response to seizure-inducing stimulation. AMPA receptor palmitoylation site could be a novel target to develop unprecedented type of anticonvulsants and GluA1C811S mice are suitable as a model animal for broadly evaluating pharmacological effectiveness of antiepileptic drugs.
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Affiliation(s)
- Madoka Iizumi
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan
| | - Akiko Oota-Ishigaki
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Mariko Yamashita
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan
| | - Takashi Hayashi
- National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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Liu H, Zhang S, Zhang L. Epileptiform activity in mouse hippocampal slices induced by moderate changes in extracellular Mg 2+, Ca 2+, and K . BMC Neurosci 2021; 22:46. [PMID: 34301200 PMCID: PMC8305515 DOI: 10.1186/s12868-021-00650-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 07/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rodent brain slices-particularly hippocampal slices-are widely used in experimental investigations of epileptiform activity. Oxygenated artificial cerebrospinal fluid (ACSF) is used to maintain slices in vitro. Physiological or standard ACSF containing 3-3.5 mM K+, 1-2 mM Mg2+, and 1-3 mM Ca2+ generally does not induce population epileptiform activity, which can be induced by ACSF with high K+ (8-10 mM), low Mg2+, or low Ca2+ alone or in combination. While low-Mg2+ ACSF without intentionally added Mg salt but with contaminating Mg2+ (≤ 50-80 µM) from other salts can induce robust epileptiform activity in slices, it is unclear whether such epileptiform activity can be achieved using ACSF with moderately decreased Mg2+. To explore this issue, we examined the effects of moderately modified (m)ACSF with 0.8 mM Mg2+, 1.3 mM Ca2+, and 5.7 mM K+ on induction of epileptiform discharges in mouse hippocampal slices. RESULTS Hippocampal slices were prepared from young (21-28 days old), middle-aged (13-14 months old), and aged (24-26 months old) C57/BL6 mice. Conventional thin (0.4 mm) and thick (0.6 mm) slices were obtained using a vibratome and pretreated with mACSF at 35-36 °C for 1 h prior to recordings. During perfusion with mACSF at 35-36 °C, spontaneous or self-sustained epileptiform field potentials following high-frequency stimulation were frequently recorded in slices pretreated with mACSF but not in those without the pretreatment. Seizure-like ictal discharges were more common in thick slices than in thin slices. CONCLUSIONS Prolonged exposure to mACSF by pretreatment and subsequent perfusion can induce epileptiform field potentials in mouse hippocampal slices.
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Affiliation(s)
- Haiyu Liu
- Department of Neurosurgery, The First Hospital of Jilin University, Jilin, China.,Graduate School of Tianjin Medical University, Tianjin, China.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Sai Zhang
- Graduate School of Tianjin Medical University, Tianjin, China.
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada. .,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada.
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Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy. Int J Mol Sci 2021; 22:ijms22083860. [PMID: 33917911 PMCID: PMC8068229 DOI: 10.3390/ijms22083860] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 12/11/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.
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Boldt L, Koska I, Maarten van Dijk R, Talbot SR, Miljanovic N, Palme R, Bleich A, Potschka H. Toward evidence-based severity assessment in mouse models with repeated seizures: I. Electrical kindling. Epilepsy Behav 2021; 115:107689. [PMID: 33418481 DOI: 10.1016/j.yebeh.2020.107689] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/01/2020] [Accepted: 12/01/2020] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Ethical decisions about an allowance for animal experiments need to be based on scientifically sound information about the burden and distress associated with the experimental procedure and models. Thereby, species differences need to be considered for recommendations regarding evidence-based severity assessment and refinement measures. METHODS A comprehensive analysis of behavioral patterns and corticosterone or its metabolites in serum and feces was completed in kindled mice. The impact of kindling via two different stimulation sites in the amygdala and hippocampus was determined. Data were compared to those from naive and electrode-implanted groups. RESULTS Amygdala and hippocampus kindled mice exhibited comparable behavioral patterns with increased activity in the open field, reduced anxiety-associated behavior in the elevated-plus maze, and increased anhedonia-associated behavior in the saccharin preference test. In addition, repeated stimulation of the hippocampus caused a reduction in burrowing behavior and an increase in active social interaction. Levels of corticosterone and its metabolites were not altered in serum or feces, respectively. A comparison of mouse data with findings from amygdala kindled rats confirmed pronounced species differences in behavioral patterns associated with the kindling process. SIGNIFICANCE Taken together the findings suggest a severity classification for the mouse kindling paradigms as moderate regardless of the stimulation site. The outcome of the species comparison provides valuable guidance for species selection for studies exploring behavioral comorbidities. In this context, it is emphasized that the mouse kindling paradigms seem to be well suited for studies exploring the link between ictal events and network alterations on the one hand, and hyperactivity and anhedonia-associated behavior on the other hand. Moreover, the underlying pathophysiological mechanisms and the impact of therapeutic interventions on these behavioral alterations can be studied in these paradigms providing guidance for the clinical management of respective psychiatric comorbidities in patients.
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Affiliation(s)
- Lena Boldt
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Ines Koska
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - R Maarten van Dijk
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Steven R Talbot
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Nina Miljanovic
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - André Bleich
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University Munich, Munich, Germany.
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Liu H, Tufa U, Zahra A, Chow J, Sivanenthiran N, Cheng C, Liu Y, Cheung P, Lim S, Jin Y, Mao M, Sun Y, Wu C, Wennberg R, Bardakjian B, Carlen PL, Eubanks JH, Song H, Zhang L. Electrographic Features of Spontaneous Recurrent Seizures in a Mouse Model of Extended Hippocampal Kindling. Cereb Cortex Commun 2021; 2:tgab004. [PMID: 34296153 PMCID: PMC8152854 DOI: 10.1093/texcom/tgab004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/08/2021] [Accepted: 01/13/2021] [Indexed: 01/14/2023] Open
Abstract
Epilepsy is a chronic neurological disorder characterized by spontaneous recurrent seizures (SRS) and comorbidities. Kindling through repetitive brief stimulation of a limbic structure is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling over a period up to a few months can induce SRS, which may simulate slowly evolving epileptogenesis of temporal lobe epilepsy. Currently, electroencephalographic (EEG) features of SRS in rodent models of extended kindling remain to be detailed. We explored this using a mouse model of extended hippocampal kindling. Intracranial EEG recordings were made from the kindled hippocampus and unstimulated hippocampal, neocortical, piriform, entorhinal, or thalamic area in individual mice. Spontaneous EEG discharges with concurrent low-voltage fast onsets were observed from the two corresponding areas in nearly all SRS detected, irrespective of associated motor seizures. Examined in brain slices, epileptiform discharges were induced by alkaline artificial cerebrospinal fluid in the hippocampal CA3, piriform and entorhinal cortical areas of extended kindled mice but not control mice. Together, these in vivo and in vitro observations suggest that the epileptic activity involving a macroscopic network may generate concurrent discharges in forebrain areas and initiate SRS in hippocampally kindled mice.
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Affiliation(s)
- Haiyu Liu
- Departments of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021 China.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Uilki Tufa
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3H5, Canada
| | - Anya Zahra
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Jonathan Chow
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Nila Sivanenthiran
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Chloe Cheng
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yapg Liu
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Phinehas Cheung
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yaozhong Jin
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Min Mao
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Richard Wennberg
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada
| | - Berj Bardakjian
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3H5, Canada
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James H Eubanks
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Surgery, University of Toronto, Toronto, Ontario M5G 1X5, Canada
| | - Hongmei Song
- Departments of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021 China.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada
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13
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Mosini AC, Calió ML, Foresti ML, Valeriano RPS, Garzon E, Mello LE. Modeling of post-traumatic epilepsy and experimental research aimed at its prevention. ACTA ACUST UNITED AC 2020; 54:e10656. [PMID: 33331416 PMCID: PMC7747873 DOI: 10.1590/1414-431x202010656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/29/2020] [Indexed: 02/06/2023]
Abstract
Research on the prevention of post-traumatic epilepsy (PTE) has seen remarkable advances regarding its physiopathology in recent years. From the search for biomarkers that might be used to indicate individual susceptibility to the development of new animal models and the investigation of new drugs, a great deal of knowledge has been amassed. Various groups have concentrated efforts in generating new animal models of traumatic brain injury (TBI) in an attempt to provide the means to further produce knowledge on the subject. Here we forward the hypothesis that restricting the search of biomarkers and of new drugs to prevent PTE by using only a limited set of TBI models might hamper the understanding of this relevant and yet not preventable medical condition.
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Affiliation(s)
- A C Mosini
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil.,Associação Brasileira de Epilepsia, São Paulo, SP, Brasil
| | - M L Calió
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - M L Foresti
- Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro, RJ, Brasil
| | - R P S Valeriano
- Divisão de Clínica Neurológica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - E Garzon
- Divisão de Clínica Neurológica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - L E Mello
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil.,Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro, RJ, Brasil
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14
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Straub J, Gawda A, Ravichandran P, McGrew B, Nylund E, Kang J, Burke C, Vitko I, Scott M, Williamson J, Joshi S, Kapur J, Perez-Reyes E. Characterization of kindled VGAT-Cre mice as a new animal model of temporal lobe epilepsy. Epilepsia 2020; 61:2277-2288. [PMID: 32954490 DOI: 10.1111/epi.16651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Development of novel therapies for temporal lobe epilepsy is hindered by a lack of models suitable for drug screening. While testing the hypothesis that "inhibiting inhibitory neurons" was sufficient to induce seizures, it was discovered that a mild electrical kindling protocol of VGAT-Cre mice led to spontaneous motor and electrographic seizures. This study characterizes these seizures and investigates the mechanism. METHODS Mice were implanted with electroencephalographic (EEG) headsets that included a stimulating electrode in the hippocampus before being electrically kindled. Seizures were evaluated by review of EEG recordings and behavior. γ-Aminobutyric acidergic (GABAergic) neurotransmission was evaluated by quantitative polymerase chain reaction, immunocytochemistry, Western blot, and electrophysiology. RESULTS Electrical kindling of VGAT-Cre mice induces spontaneous recurring seizures after a short latency (6 days). Seizures occur 1-2 times per day in both male and female mice, with only minimal neuronal death. These mice express Cre recombinase under the control of the vesicular GABA transporter (VGAT), a gene that is specifically expressed in GABAergic inhibitory neurons. The insertion of Cre disrupts the expression of VGAT mRNA and protein, and impairs GABAergic synaptic transmission in the hippocampus. SIGNIFICANCE Kindled VGAT-Cre mice can be used to study the mechanisms involved in epileptogenesis and may be useful for screening novel therapeutics.
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Affiliation(s)
- Justyna Straub
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Agnieszka Gawda
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Pranav Ravichandran
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Bailey McGrew
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Elsa Nylund
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Julianna Kang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Cassidy Burke
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Iuliia Vitko
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Michael Scott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - John Williamson
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA
| | - Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, Virginia, USA.,UVA Brain Institute, University of Virginia, Charlottesville, Virginia, USA
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA.,UVA Brain Institute, University of Virginia, Charlottesville, Virginia, USA
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15
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Ahmed Juvale II, Che Has AT. The evolution of the pilocarpine animal model of status epilepticus. Heliyon 2020; 6:e04557. [PMID: 32775726 PMCID: PMC7393986 DOI: 10.1016/j.heliyon.2020.e04557] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/05/2020] [Accepted: 07/22/2020] [Indexed: 02/02/2023] Open
Abstract
The pilocarpine animal model of status epilepticus is a well-established, clinically translatable model that satisfies all of the criteria essential for an animal model of status epilepticus: a latency period followed by spontaneous recurrent seizures, replication of behavioural, electrographic, metabolic, and neuropathological changes, as well as, pharmacoresistance to anti-epileptic drugs similar to that observed in human status epilepticus. However, this model is also characterized by high mortality rates and studies in recent years have also seen difficulties in seizure induction due to pilocarpine resistant animals. This can be attributed to differences in rodent strains, species, gender, and the presence of the multi-transporter, P-glycoprotein at the blood brain barrier. The current paper highlights the various alterations made to the original pilocarpine model over the years to combat both the high mortality and low induction rates. These range from the initial lithium-pilocarpine model to the more recent Reduced Intensity Status Epilepticus (RISE) model, which finally brought the mortality rates down to 1%. These modifications are essential to improve animal welfare and future experimental outcomes.
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Affiliation(s)
- Iman Imtiyaz Ahmed Juvale
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
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16
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Sabetghadam A, Wu C, Liu J, Zhang L, Reid AY. Increased epileptogenicity in a mouse model of neurofibromatosis type 1. Exp Neurol 2020; 331:113373. [PMID: 32502580 DOI: 10.1016/j.expneurol.2020.113373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 11/19/2022]
Abstract
RATIONALE Neurofibromatosis type 1 (NF1) is associated with higher rates of epilepsy compared to the general population. Some NF1 patients with epilepsy do not have intracranial lesions, suggesting the genetic mutation itself may contribute to higher rates of epilepsy in these patients. We have recently demonstrated increased seizure susceptibility in the Nf1+/- mouse, but it is unknown whether this model displays altered epileptogenicity, as has been reported in patients with NF1. The aim of this study was to determine whether the Nf1+/- mouse is more susceptible to electrical kindling-induced epileptogenesis. METHODS Young male or female adult Nf1+/- or Nf1+/+ (wild-type; WT) mice were implanted with electrodes for neocortical or hippocampal kindling paradigms. Neocortical kindling was performed for 40 stimulation sessions followed by baseline EEG monitoring to detect possible SRSs. Hippocampal kindling was performed with a modified extended kindling paradigm, completed to a maximum of 80 sessions to try to induce spontaneous repetitive seizures (SRSs). Western blot assays were performed in naïve and kindled mice to compare levels of Akt and MAPK (ERK1/2), proteins downstream of the NF1 mutation. RESULTS The average initial neocortical after-discharge threshold (ADT) was significantly lower in the Nf1+/- group, which also required fewer stimulations to reach stage 5 seizure, had greater average seizure severity across all kindling sessions, had a greater number of convulsive seizures, and had a faster progression of after-discharge duration and Racine score during kindling. No WT mice exhibited SRS after neocortical kindling, versus 33% of Nf1+/- mice. The average initial hippocampal ADT was not significantly different between the WT and Nf1+/- groups, nor was there a difference in the number of stimulations required to reach the kindled state. The WT group had a significantly higher average seizure severity across all kindling sessions as compared with the Nf1+/- mice. The WT group also had faster progression of the Racine seizure score over the kindling sessions, mainly due to a faster increase in seizures severity early during the kindling process. However, SRSs were seen in 50% of Nf1+/- mice after modified extended kindling and in no WT mice. Western blots showed hippocampal kindling increased the ratio of phosphorylated/total Akt in both the WT and Nf1+/- mice, while neocortical kindling led to increased ratios of phosphorylated/total Akt and MAPK in Nf1+/- mice only. CONCLUSIONS We have demonstrated for the first time an increased rate of epileptogenesis in an animal model of NF1 with no known macroscopic/neoplastic brain lesions. This work provides evidence for the genetic mutation itself playing a role in seizures and epilepsy in patients with NF1, and supports the use of the Nf1+/- mouse model in future mechanistic studies.
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Affiliation(s)
- A Sabetghadam
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada.
| | - C Wu
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - J Liu
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - L Zhang
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
| | - A Y Reid
- Krembil Research Institute, University Health Network, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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17
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Jung ME, Metzger DB, Hall J. The long-term but not short-term use of benzodiazepine impairs motoric function and upregulates amyloid β in part through the suppression of translocator protein. Pharmacol Biochem Behav 2020; 191:172873. [PMID: 32105662 DOI: 10.1016/j.pbb.2020.172873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/22/2020] [Accepted: 02/15/2020] [Indexed: 11/24/2022]
Abstract
Many elderly American women use CNS depressant benzodiazepine (BZD) to ameliorate anxiety or insomnia. However, the chronic use of BZD (cBZD) is prevalent, causing adverse effects of BZD that include movement deficit. We previously reported that cBZD upregulates neurotoxic amyloid β42 (Aβ42) and downregulates neuroprotective translocator protein (TSPO) in the cerebellum, the brain area of movement and balance. The aim of the current study is two-fold: 1) to determine a direct effect of TSPO (inhibition) on cBZD-induced Aβ42 and Aβ-associated molecules; Aβ-producing-protein presenilin-1 (PS1) and Aβ-degrading-enzyme neprilysin and 2) to determine whether Aβ42 upregulation and motoric deficit occur upon a long-term (cBZD) rather than a short-term BZD (sBZD) treatment. Old female mice received BZD (lorazepam) for 20 days (cBZD) or 3 days (sBZD) with or without prototype TSPO ligand PK11195 and were tested for motoric performance for 3 days using Rotarod. ELISA was conducted to measure Aβ42 level and neprilysin activity in cerebellum. RT-PCR and immunoblot were conducted to measure the mRNA and protein levels of TSPO, PS1, and neprilysin. cBZD treatment decreased TSPO and neprilysin but increased Aβ42 accompanied by motoric deficit. Chronic PK11195 treatment acted as a TSPO inhibitor by suppressing TSPO expression and mimicked or exacerbated the effects of cBZD on all parameters measured except for PS1. None of the molecular and behavioral changes induced by cBZD were reproduced by sBZD treatment. These data suggest that cBZD upregulates Aβ42 and downregulates neprilysin in part through TSPO inhibition, the mechanisms distinct from sBZD, collectively contributing to motoric deficit.
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Affiliation(s)
- Marianna E Jung
- Pharmacology and Neuroscience, UNT Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States of America.
| | - Daniel B Metzger
- Pharmacology and Neuroscience, UNT Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States of America
| | - James Hall
- Pharmacology and Neuroscience, UNT Health Science Center, Institute for Healthy Aging, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, United States of America
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18
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Ma K, Bin NR, Shi S, Harada H, Wada Y, Wada GHS, Monnier PP, Sugita S, Zhang L. Observations From a Mouse Model of Forebrain Voa1 Knockout: Focus on Hippocampal Structure and Function. Front Cell Neurosci 2019; 13:484. [PMID: 31824264 PMCID: PMC6881385 DOI: 10.3389/fncel.2019.00484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/11/2019] [Indexed: 12/22/2022] Open
Abstract
Voa protein is a subunit of V-ATPase proton pump which is essential to acidify intracellular organelles including synaptic vesicles. Voa1 is one of the four isoforms of Voa family with strong expression in neurons. Our present study was aimed to examine the role of Voa1 protein in mammalian brain neurons. To circumvent embryonic lethality, we generated conditional Voa1 knockout mice in which Voa1 was selectively deleted from forebrain pyramidal neurons. We performed experiments in the Voa1 knockout mice of ages 5-6 months to assess the persistent effects of Voa1 deletion. We found that the Voa1 knockout mice exhibited poor performance in the Morris water maze test compared to control mice. In addition, synaptic field potentials of the hippocampal CA1 region were greatly diminished in the Voa1 knockout mice when examined in brain slices in vitro. Furthermore, brain histological experiments showed severe degeneration of dorsal hippocampal CA1 neurons while CA3 neurons were largely preserved. The CA1 neurodegeneration was associated with general brain atrophy as overall hemispheric areas were reduced in the Voa1 cKO mice. Despite the CA1 degeneration and dysfunction, electroencephalographic recordings from the hippocampal CA3 area revealed aberrant spikes and non-convulsive discharges in the Voa1 knockout mice but not in control mice. These hippocampal spikes were suppressed by single intra-peritoneal injection of diazepam which is a benzodiazepine GABAA receptor enhancer. Together these results suggest that Voa1 related activities are essential for the survival of the targeted neurons in the dorsal hippocampal CA1 as well as other forebrain areas. We postulate that the Voa1 knockout mice may serve as a valuable model for further investigation of V-ATPase dysfunction related neuronal degeneration and functional abnormalities in forebrain areas particularly the hippocampus.
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Affiliation(s)
- Ke Ma
- Department of Pediatric Outpatient, The First Hospital of Jilin University, Jilin, China.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Na-Ryum Bin
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Shan Shi
- Department of Pediatric Outpatient, The First Hospital of Jilin University, Jilin, China.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Hidekiyo Harada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Yoh Wada
- Division of Biological Science, Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Ge-Hong-Sun Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyoto, Japan
| | - Philippe P Monnier
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Ophthalmology, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Shuzo Sugita
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, 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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19
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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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20
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Song H, Mylvaganam SM, Wang J, Mylvaganam SMK, Wu C, Carlen PL, Eubanks JH, Feng J, Zhang L. Contributions of the Hippocampal CA3 Circuitry to Acute Seizures and Hyperexcitability Responses in Mouse Models of Brain Ischemia. Front Cell Neurosci 2018; 12:278. [PMID: 30210302 PMCID: PMC6123792 DOI: 10.3389/fncel.2018.00278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/08/2018] [Indexed: 12/29/2022] Open
Abstract
The hippocampal circuitry is widely recognized as susceptible to ischemic injury and seizure generation. However, hippocampal contribution to acute non-convulsive seizures (NCS) in models involving middle cerebral artery occlusion (MCAO) remains to be determined. To address this, we occluded the middle cerebral artery in adult C57 black mice and monitored electroencephalographic (EEG) discharges from hippocampal and neocortical areas. Electrographic discharges in the absence of convulsive motor behaviors were observed within 90 min following occlusion of the middle cerebral artery. Hippocampal discharges were more robust than corresponding cortical discharges in all seizure events examined, and hippocampal discharges alone or with minimal cortical involvement were also observed in some seizure events. Seizure development was associated with ipsilateral hippocampal injuries as determined by subsequent histological examinations. We also introduced hypoxia-hypoglycemia episodes in mouse brain slices and examined regional hyperexcitable responses ex vivo. Extracellular recordings showed that the hippocampal CA3 region had a greater propensity for exhibiting single/multiunit activities or epileptiform field potentials following hypoxic-hypoglycemic (HH) episodes compared to the CA1, dentate gyrus, entorhinal cortical (EC) or neocortical regions. Whole-cell recordings revealed that CA3 pyramidal neurons exhibited excessive excitatory postsynaptic currents, attenuated inhibitory postsynaptic currents and intermittent or repetitive spikes in response to HH challenge. Together, these observations suggest that hippocampal discharges, possibly as a result of CA3 circuitry hyperexcitability, are a major component of acute NCS in a mouse model of MCAO.
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Affiliation(s)
- Hongmei Song
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | | | - Justin Wang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | | | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Peter L. Carlen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - James H. Eubanks
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Canada
| | - Jiachun Feng
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
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