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Yuskaitis CJ, Modasia JB, Schrötter S, Rossitto LA, Groff KJ, Morici C, Mithal DS, Chakrabarty RP, Chandel NS, Manning BD, Sahin M. DEPDC5-dependent mTORC1 signaling mechanisms are critical for the anti-seizure effects of acute fasting. Cell Rep 2022; 40:111278. [PMID: 36044864 PMCID: PMC9508617 DOI: 10.1016/j.celrep.2022.111278] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/11/2022] [Accepted: 08/05/2022] [Indexed: 11/30/2022] Open
Abstract
Caloric restriction and acute fasting are known to reduce seizures but through unclear mechanisms. mTOR signaling has been suggested as a potential mechanism for seizure protection from fasting. We demonstrate that brain mTORC1 signaling is reduced after acute fasting of mice and that neuronal mTORC1 integrates GATOR1 complex-mediated amino acid and tuberous sclerosis complex (TSC)-mediated growth factor signaling. Neuronal mTORC1 is most sensitive to withdrawal of leucine, arginine, and glutamine, which are dependent on DEPDC5, a component of the GATOR1 complex. Metabolomic analysis reveals that Depdc5 neuronal-specific knockout mice are resistant to sensing significant fluctuations in brain amino acid levels after fasting. Depdc5 neuronal-specific knockout mice are resistant to the protective effects of fasting on seizures or seizure-induced death. These results establish that acute fasting reduces seizure susceptibility in a DEPDC5-dependent manner. Modulation of nutrients upstream of GATOR1 and mTORC1 could offer a rational therapeutic strategy for epilepsy treatment.
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Affiliation(s)
- Christopher J Yuskaitis
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jinita B Modasia
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sandra Schrötter
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Leigh-Ana Rossitto
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Karenna J Groff
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Christopher Morici
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Divakar S Mithal
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Section of Neurology, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Ram P Chakrabarty
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Navdeep S Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Brendan D Manning
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, USA.
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2
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Serotonin Pretreatment Abolishes Sex-specific NMDA-induced Seizure Behavior in Developing Rats. Neuroscience 2021; 463:184-196. [PMID: 33838289 DOI: 10.1016/j.neuroscience.2021.03.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022]
Abstract
Neuronal excitability and susceptibility to excitotoxic damage can be sex-specific, with neurons from males usually being more 'easily excitable' compared to neurons from females, especially during development. Increased excitability at an individual neuronal level can lead to the formation of hyperexcitable neuronal networks, which, consequently can make the brain more seizure prone. Both animal and clinical data suggest that males experience more frequent and severe seizures than do females. Serotonin (5-hydroxytryptamine; 5-HT) can mediate neuronal excitability and seizure behavior, often serving as an anticonvulsant. Importantly, 5-HT signaling during parts of the perinatal period is sexually dimorphic. Sex differences during development have been reported in both serotonin levels and receptor type (excitatory vs. inhibitory) expression in a manner that may leave the male brain more vulnerable to over-excitation. Thus, we aimed to determine if the anticonvulsant effects of 5-HT were sex- and/or age-dependent in juvenile animals. We report a baseline sex difference in N-methyl-d-aspartate (NMDA)-induced seizure behavior and hippocampal neuronal loss, with postnatal day (PND) 14 males exhibiting more severe seizure behavior compared to females. Pretreatment with the general 5-HT receptor agonist 5-methoxytryptamine (5-MT) abolishes baseline sex differences, providing an anticonvulsant effect for males only. These sex differences appear to be at least in part organized by testosterone, as females given neonatal androgen exhibit a seizure behavior profile in between that of males and females.
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3
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Sadanandan N, Saft M, Gonzales-Portillo B, Borlongan CV. Multipronged Attack of Stem Cell Therapy in Treating the Neurological and Neuropsychiatric Symptoms of Epilepsy. Front Pharmacol 2021; 12:596287. [PMID: 33815100 PMCID: PMC8010689 DOI: 10.3389/fphar.2021.596287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/15/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy stands as a life-threatening disease that is characterized by unprovoked seizures. However, an important characteristic of epilepsy that needs to be examined is the neuropsychiatric aspect. Epileptic patients endure aggression, depression, and other psychiatric illnesses. Therapies for epilepsy can be divided into two categories: antiepileptic medications and surgical resection. Antiepileptic drugs are used to attenuate heightened neuronal firing and to lessen seizure frequency. Alternatively, surgery can also be conducted to physically cut out the area of the brain that is assumed to be the root cause for the anomalous firing that triggers seizures. While both treatments serve as viable approaches that aim to regulate seizures and ameliorate the neurological detriments spurred by epilepsy, they do not serve to directly counteract epilepsy's neuropsychiatric traits. To address this concern, a potential new treatment involves the use of stem cells. Stem cell therapy has been employed in experimental models of neurological maladies, such as Parkinson's disease, and neuropsychiatric illnesses like depression. Cell-based treatments for epilepsy utilizing stem cells such as neural stem cells (NSCs), mesenchymal stem cells (MSCs), and interneuron grafts have been explored in preclinical and clinical settings, highlighting both the acute and chronic stages of epilepsy. However, it is difficult to create an animal model to capitalize on all the components of epilepsy due to the challenges in delineating the neuropsychiatric aspect. Therefore, further preclinical investigation into the safety and efficacy of stem cell therapy in addressing both the neurological and the neuropsychiatric components of epilepsy is warranted in order to optimize cell dosage, delivery, and timing of cell transplantation.
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Affiliation(s)
| | | | | | - Cesar V. Borlongan
- Department of Neurosurgery and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, United States
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4
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Canzian J, Franscescon F, Müller TE, Stefanello FV, Souza TP, Rosa LV, Rosemberg DB. Stress increases susceptibility to pentylenetetrazole-induced seizures in adult zebrafish. Epilepsy Behav 2021; 114:107557. [PMID: 33243678 DOI: 10.1016/j.yebeh.2020.107557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/08/2020] [Accepted: 09/28/2020] [Indexed: 12/16/2022]
Abstract
Stress is the body's reaction to any change that requires adaptive responses. In various organisms, stress is a seizure-related comorbidity. Despite the exposure to stressors eliciting aversive behaviors in zebrafish, there are no data showing whether stress potentiates epileptic seizures in this species. Here, we investigated whether a previous exposure to an intense acute stressor positively modulates the susceptibility to seizures in pentylenetetrazole (PTZ)-challenged zebrafish. The conspecific alarm substance (CAS) was used to elicit aversive responses (3.5 mL/L for 5 min), observed by increased bottom dwelling and erratic movements. Then, fish were immediately exposed to 7.5 mM PTZ for 10 min to induce seizure-like behaviors. Stress increased the seizure intensity, the number of clonic-like seizure behaviors (score 4), as well as facilitated the occurrence of score 4 episodes by decreasing the latency in which fish reached the score 4. Moreover, fish with heightened anxiety showed increased susceptibility to PTZ, since positive correlations between anxiety- and seizure-like behaviors were found. Overall, since CAS also increased whole-body cortisol levels in zebrafish, our novel findings show a prominent response to PTZ-induced seizures in previously stressed zebrafish. Moreover, we reinforce the growing utility of zebrafish models to assess seizure-related comorbidities aiming to elucidate how stress can affect epileptic seizures in vertebrates.
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Affiliation(s)
- Julia Canzian
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - Francini Franscescon
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - Talise E Müller
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - Flavia V Stefanello
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - Thiele P Souza
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - Luiz V Rosa
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil
| | - Denis B Rosemberg
- Laboratory of Experimental Neuropsychobiology, Department of Biochemistry and Molecular Biology, Natural and Exact Sciences Center, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; Graduate Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, 1000 Roraima Avenue, Santa Maria, RS 97105-900, Brazil; The International Zebrafish Neuroscience Research Consortium (ZNRC), 309 Palmer Court, Slidell, LA 70458, USA.
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5
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Ribot R, Kanner AM. Neurobiologic properties of mood disorders may have an impact on epilepsy: Should this motivate neurologists to screen for this psychiatric comorbidity in these patients? Epilepsy Behav 2019; 98:298-301. [PMID: 31182393 DOI: 10.1016/j.yebeh.2019.01.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 12/24/2022]
Abstract
Epilepsy and psychiatric comorbidities have a complex relation, which can be manifested by their relatively high comorbid occurrence and the existence of a bidirectional relation, whereby not only are people with epilepsy (PWE) at greater risk of developing psychiatric disorders, but patients with primary psychiatric disorders are at higher risk of developing epilepsy. The existence of common pathogenic mechanisms operant in primary psychiatric disorders and epilepsy has been postulated as one of the leading hypothesis to explain their close and very complex relation. The neurobiologic characteristics of mood disorders can be used as a model to test this hypothesis. In this manuscript, we highlight data that suggest how several neurobiologic aspects of mood disorders can facilitate the epileptogenic process in animal models and explain the increased risk of patients with primary mood disorders to develop epilepsy in general and treatment-resistant epilepsy in particular. It is our hope that the inclusion of these data in this Special Issue will motivate neurologists to screen common psychiatric comorbidities in PWE. This article is part of the Special Issue "Obstacles of Treatment of Psychiatric Comorbidities in Epilepsy".
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Affiliation(s)
- Ramses Ribot
- Comprehensive Epilepsy Center and Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, United States of America
| | - Andres M Kanner
- Comprehensive Epilepsy Center and Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, United States of America.
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6
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Aguilar BL, Malkova L, N'Gouemo P, Forcelli PA. Genetically Epilepsy-Prone Rats Display Anxiety-Like Behaviors and Neuropsychiatric Comorbidities of Epilepsy. Front Neurol 2018; 9:476. [PMID: 29997563 PMCID: PMC6030811 DOI: 10.3389/fneur.2018.00476] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/01/2018] [Indexed: 01/09/2023] Open
Abstract
Epilepsy is associated with a variety of neuropsychiatric comorbidities, including both anxiety and depression. Despite high occurrences of depression and anxiety seen in human epilepsy populations, little is known about the etiology of these comorbidities. Experimental models of epilepsy provide a platform to disentangle the contribution of acute seizures, genetic predisposition, and underlying circuit pathologies to anxious and depressive phenotypes. Most studies to date have focused on comorbidities in acquired epilepsies; genetic models, however, allow for the assessment of affective phenotypes that occur prior to onset of recurrent seizures. Here, we tested male and female genetically epilepsy-prone rats (GEPR-3s) and Sprague-Dawley controls in a battery of tests sensitive to anxiety-like and depressive-like phenotypes. GEPR-3s showed increased anxiety-like behavior in the open field test, elevated plus maze, light-dark transition test, and looming threat test. Moreover, GEPR-3s showed impaired prepulse inhibition of the acoustic startle reflex, decreased sucrose preference index, and impaired novel object recognition memory. We also characterized defense behaviors in response to stimulation thresholds of deep and intermediate layers of the superior colliculus (DLSC), but found no difference between strains. In sum, GEPR-3s showed inherited anxiety, an effect that did not differ significantly between sexes. The anxiety phenotype in adult GEPR-3s suggests strong genetic influences that may underlie both the seizure disorder and the comorbidities seen in epilepsy.
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Affiliation(s)
- Brittany L Aguilar
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States.,Department of Pharmacology and Physiology, Georgetown University, Washington, DC, United States
| | - Ludise Malkova
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States.,Department of Pharmacology and Physiology, Georgetown University, Washington, DC, United States
| | - Prosper N'Gouemo
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States.,Department of Pediatrics, Georgetown University, Washington, DC, United States
| | - Patrick A Forcelli
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States.,Department of Pharmacology and Physiology, Georgetown University, Washington, DC, United States.,Department of Neuroscience, Georgetown University, Washington, DC, United States
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7
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Lee Y, Rodriguez OC, Albanese C, Santos VR, Cortes de Oliveira JA, Donatti ALF, Fernandes A, Garcia-Cairasco N, N'Gouemo P, Forcelli PA. Divergent brain changes in two audiogenic rat strains: A voxel-based morphometry and diffusion tensor imaging comparison of the genetically epilepsy prone rat (GEPR-3) and the Wistar Audiogenic Rat (WAR). Neurobiol Dis 2017; 111:80-90. [PMID: 29274430 DOI: 10.1016/j.nbd.2017.12.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/24/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023] Open
Abstract
Acoustically evoked seizures (e.g., audiogenic seizures or AGS) are common in models of inherited epilepsy and occur in a variety of species including rat, mouse, and hamster. Two models that have been particularly well studied are the genetically epilepsy prone rat (GEPR-3) and the Wistar Audiogenic Rat (WAR) strains. Acute and repeated AGS, as well as comorbid conditions, displays a close phenotypic overlap in these models. Whether these similarities arise from convergent or divergent structural changes in the brain remains unknown. Here, we examined the brain structure of Sprague Dawley (SD) and Wistar (WIS) rats, and quantified changes in the GEPR-3 and WAR, respectively. Brains from adult, male rats of each strain (n=8-10 per group) were collected, fixed, and embedded in agar and imaged using a 7 tesla Bruker MRI. Post-acquisition analysis included voxel-based morphometry (VBM), diffusion tensor imaging (DTI), and manual volumetric tracing. In the VBM analysis, GEPR-3 displayed volumetric changes in brainstem structures known to be engaged by AGS (e.g., superior and inferior colliculus, periaqueductal grey) and in forebrain structures (e.g., striatum, septum, nucleus accumbens). WAR displayed volumetric changes in superior colliculus, and a broader set of limbic regions (e.g., hippocampus, amygdala/piriform cortex). The only area of significant overlap in the two strains was the midline cerebellum: both GEPR-3 and WAR showed decreased volume compared to their control strains. In the DTI analysis, GEPR-3 displayed decreased fractional anisotropy (FA) in the corpus callosum, posterior commissure and commissure of the inferior colliculus (IC). WAR displayed increased FA only in the commissure of IC. These data provide a biological basis for further comparative and mechanistic studies in the GEPR-3 and WAR models, as well as provide additional insight into commonalities in the pathways underlying AGS susceptibility and behavioral comorbidity.
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Affiliation(s)
- Yichien Lee
- Preclinical Research Imaging Laboratory, Georgetown University, Washington, DC, USA; Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA; Department of Pathology, Georgetown University, Washington, DC, USA
| | - Olga C Rodriguez
- Preclinical Research Imaging Laboratory, Georgetown University, Washington, DC, USA; Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA; Department of Pathology, Georgetown University, Washington, DC, USA
| | - Chris Albanese
- Preclinical Research Imaging Laboratory, Georgetown University, Washington, DC, USA; Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA; Department of Pathology, Georgetown University, Washington, DC, USA; Department of Oncology, Georgetown University, Washington, DC, USA
| | | | - José Antônio Cortes de Oliveira
- Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Ana Luiza Ferreira Donatti
- Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Artur Fernandes
- Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil; Laboratory of Epigenetics and Reproduction, Department of Genetics, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Norberto Garcia-Cairasco
- Neurophysiology and Experimental Neuroethology Laboratory (LNNE), Department of Physiology, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Prosper N'Gouemo
- Department of Pediatrics, Georgetown University, Washington, DC, USA; Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA
| | - Patrick A Forcelli
- Department of Pharmacology & Physiology, Georgetown University, Washington, DC, USA; Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, USA; Department of Neuroscience, Georgetown University, Washington, DC, USA.
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8
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Serotonin depletion increases seizure susceptibility and worsens neuropathological outcomes in kainate model of epilepsy. Brain Res Bull 2017; 134:109-120. [PMID: 28716398 DOI: 10.1016/j.brainresbull.2017.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022]
Abstract
Serotonin is implicated in the regulation of seizures, but whether or not it can potentiate the effects of epileptogenic factors is not fully established. Using the kainic acid model of epilepsy in rats, we tested the effects of serotonin depletion on (1) susceptibility to acute seizures, (2) development of spontaneous recurrent seizures and (3) behavioral and neuroanatomical sequelae of kainic acid treatment. Serotonin was depleted by pretreating rats with p-chlorophenylalanine. In different groups, kainic acid was injected at 3 different doses: 6.5mg/kg, 9.0mg/kg or 12.5mg/kg. A single dose of 6.5mg/kg of kainic acid reliably induced status epilepticus in p-chlorophenylalanine-pretreated rats, but not in saline-pretreated rats. The neuroexcitatory effects of kainic acid in the p-chlorophenylalanine-pretreated rats, but not in saline-pretreated rats, were associated with the presence of tonic-clonic convulsions and high lethality. Compared to controls, a greater portion of serotonin-depleted rats showed spontaneous recurrent seizures after kainic acid injections. Loss of hippocampal neurons and spatial memory deficits associated with kainic acid treatment were exacerbated by prior depletion of serotonin. The present findings are of particular importance because they suggest that low serotonin activity may represent one of the major risk factors for epilepsy and, thus, offer potentially relevant targets for prevention of epileptogenesis.
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9
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Kanner AM. Can Neurochemical Changes of Mood Disorders Explain the Increase Risk of Epilepsy or its Worse Seizure Control? Neurochem Res 2017; 42:2071-2076. [PMID: 28667464 DOI: 10.1007/s11064-017-2331-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/12/2017] [Accepted: 06/13/2017] [Indexed: 12/29/2022]
Abstract
The existence of a bidirectional relation between mood disorders and epilepsy has been suggested by six population-based studies. Furthermore, three studies have associated a higher risk of treatment-resistant epilepsy with a history of depression preceding the onset of epilepsy. Common pathogenic mechanisms operant in depression and epilepsy may provide a possible explanation of these observations. This article reviews some of the leading pathogenic mechanisms of depression with respect to potential proconvulsant properties that may provide explanations for these phenomena.
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Affiliation(s)
- Andres M Kanner
- Department of Neurology, University of Miami, Miller School of Medicine, 1120 NW 14th Street, Room #1324, Miami, FL, 33136, USA.
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10
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Genetically epilepsy-prone rats (GEPRs) and DBA/2 mice: Two animal models of audiogenic reflex epilepsy for the evaluation of new generation AEDs. Epilepsy Behav 2017; 71:165-173. [PMID: 26254980 DOI: 10.1016/j.yebeh.2015.06.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 01/08/2023]
Abstract
This review summarizes the current knowledge about DBA/2 mice and genetically epilepsy-prone rats (GEPRs) and discusses the contribution of such animal models on the investigation of possible new therapeutic targets and new anticonvulsant compounds for the treatment of epilepsy. Also, possible chemical or physical agents acting as proconvulsant agents are described. Abnormal activities of enzymes involved in catecholamine and serotonin synthesis and metabolism were reported in these models, and as a result of all these abnormalities, seizure susceptibility in both animals is greatly affected by pharmacological manipulations of the brain levels of monoamines and, prevalently, serotonin. In addition, both genetic epileptic models permit the evaluation of pharmacodynamic and pharmacokinetic interactions among several drugs measuring plasma and/or brain level of each compound. Audiogenic models of epilepsy have been used not only for reflex epilepsy studies, but also as animal models of epileptogenesis. The seizure predisposition (epileptiform response to sound stimulation) and substantial characterization of behavioral, cellular, and molecular alterations in both acute and chronic (kindling) protocols potentiate the usefulness of these models in elucidating ictogenesis, epileptogenesis, and their mechanisms. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".
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11
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Rao G, Mashkouri S, Aum D, Marcet P, Borlongan CV. Contemplating stem cell therapy for epilepsy-induced neuropsychiatric symptoms. Neuropsychiatr Dis Treat 2017; 13:585-596. [PMID: 28260906 PMCID: PMC5328607 DOI: 10.2147/ndt.s114786] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Epilepsy is a debilitating disease that impacts millions of people worldwide. While unprovoked seizures characterize its cardinal symptom, an important aspect of epilepsy that remains to be addressed is the neuropsychiatric component. It has been documented for millennia in paintings and literature that those with epilepsy can suffer from bouts of aggression, depression, and other psychiatric ailments. Current treatments for epilepsy include the use of antiepileptic drugs and surgical resection. Antiepileptic drugs reduce the overall firing of the brain to mitigate the rate of seizure occurrence. Surgery aims to remove a portion of the brain that is suspected to be the source of aberrant firing that leads to seizures. Both options treat the seizure-generating neurological aspect of epilepsy, but fail to directly address the neuropsychiatric components. A promising new treatment for epilepsy is the use of stem cells to treat both the biological and psychiatric components. Stem cell therapy has been shown efficacious in treating experimental models of neurological disorders, including Parkinson's disease, and neuropsychiatric diseases, such as depression. Additional research is necessary to see if stem cells can treat both neurological and neuropsychiatric aspects of epilepsy. Currently, there is no animal model that recapitulates all the clinical hallmarks of epilepsy. This could be due to difficulty in characterizing the neuropsychiatric component of the disease. In advancing stem cell therapy for treating epilepsy, experimental testing of the safety and efficacy of allogeneic and autologous transplantation will require the optimization of cell dosage, delivery, and timing of transplantation in a clinically relevant model of epilepsy with both neurological and neuropsychiatric symptoms of the disease as the primary outcome measures.
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Affiliation(s)
- Gautam Rao
- Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Sherwin Mashkouri
- Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - David Aum
- Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Paul Marcet
- Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA
| | - Cesar V Borlongan
- Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA
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12
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Fonseca NC, Joaquim HPG, Talib LL, Vincentiis S, Gattaz WF, Valente KD. 5-hydroxytryptamine1A receptor density in the hippocampus of patients with temporal lobe epilepsy is associated with disease duration. Eur J Neurol 2017; 24:602-608. [DOI: 10.1111/ene.13252] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 01/04/2017] [Indexed: 11/30/2022]
Affiliation(s)
- N. C. Fonseca
- Institute and Department of Psychiatry; University of São Paulo; São Paulo
| | - H. P. G. Joaquim
- Laboratory of Neuroscience; Institute and Department of Psychiatry; Clinical Hospital; University of São Paulo; São Paulo
| | - L. L. Talib
- Laboratory of Neuroscience; Institute and Department of Psychiatry; Clinical Hospital; University of São Paulo; São Paulo
| | - S. Vincentiis
- Institute and Department of Psychiatry; University of São Paulo; São Paulo
- Laboratory of Neuroimaging; Institute and Department of Psychiatry; University of São Paulo; São Paulo Brazil
| | - W. F. Gattaz
- Laboratory of Neuroscience; Institute and Department of Psychiatry; Clinical Hospital; University of São Paulo; São Paulo
| | - K. D. Valente
- Institute and Department of Psychiatry; University of São Paulo; São Paulo
- Laboratory of Neuroimaging; Institute and Department of Psychiatry; University of São Paulo; São Paulo Brazil
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Svob Strac D, Pivac N, Smolders IJ, Fogel WA, De Deurwaerdere P, Di Giovanni G. Monoaminergic Mechanisms in Epilepsy May Offer Innovative Therapeutic Opportunity for Monoaminergic Multi-Target Drugs. Front Neurosci 2016; 10:492. [PMID: 27891070 PMCID: PMC5102907 DOI: 10.3389/fnins.2016.00492] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 10/13/2016] [Indexed: 12/22/2022] Open
Abstract
A large body of experimental and clinical evidence has strongly suggested that monoamines play an important role in regulating epileptogenesis, seizure susceptibility, convulsions, and comorbid psychiatric disorders commonly seen in people with epilepsy (PWE). However, neither the relative significance of individual monoamines nor their interaction has yet been fully clarified due to the complexity of these neurotransmitter systems. In addition, epilepsy is diverse, with many different seizure types and epilepsy syndromes, and the role played by monoamines may vary from one condition to another. In this review, we will focus on the role of serotonin, dopamine, noradrenaline, histamine, and melatonin in epilepsy. Recent experimental, clinical, and genetic evidence will be reviewed in consideration of the mutual relationship of monoamines with the other putative neurotransmitters. The complexity of epileptic pathogenesis may explain why the currently available drugs, developed according to the classic drug discovery paradigm of "one-molecule-one-target," have turned out to be effective only in a percentage of PWE. Although, no antiepileptic drugs currently target specifically monoaminergic systems, multi-target directed ligands acting on different monoaminergic proteins, present on both neurons and glia cells, may represent a new approach in the management of seizures, and their generation as well as comorbid neuropsychiatric disorders.
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Affiliation(s)
| | - Nela Pivac
- Division of Molecular Medicine, Rudjer Boskovic InstituteZagreb, Croatia
| | - Ilse J. Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit BrusselBrussels, Belgium
| | - Wieslawa A. Fogel
- Department of Hormone Biochemistry, Medical University of LodzLodz, Poland
| | | | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, University of MaltaMsida, Malta
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Mazarati A, Sankar R. Common Mechanisms Underlying Epileptogenesis and the Comorbidities of Epilepsy. Cold Spring Harb Perspect Med 2016; 6:6/7/a022798. [PMID: 27371669 DOI: 10.1101/cshperspect.a022798] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The importance of comorbidities in determining the quality of life of individuals with epilepsy and their families has received increasing attention in the past decade. Along with it has come a recognition that in some individuals, certain comorbidities may have preexisted, and may have contributed to their developing epilepsy. Many mechanisms are capable of interconnecting different dysfunctions that manifest as distinct disorders, often diagnosed and managed by different specialists. We review the human data from the perspective of epidemiology as well as insights gathered from neurodiagnostic and endocrine studies. Animal studies are reviewed to refine our mechanistic understanding of the connections, because they permit the narrowing of variables, which is not possible when studying humans.
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Affiliation(s)
- Andrey Mazarati
- Department of Pediatrics, Division of Pediatric Neurology, David Geffen School of Medicine at UCLA, UCLA Medical Center, Los Angeles, California 90095-1752
| | - Raman Sankar
- Department of Pediatrics, Division of Pediatric Neurology, David Geffen School of Medicine at UCLA, UCLA Medical Center, Los Angeles, California 90095-1752 Department of Neurology, David Geffen School of Medicine at UCLA, UCLA Medical Center, Los Angeles, California 90095-1752
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Banach M, Popławska M, Błaszczyk B, Borowicz KK, Czuczwar SJ. Pharmacokinetic/pharmacodynamic considerations for epilepsy - depression comorbidities. Expert Opin Drug Metab Toxicol 2016; 12:1067-80. [PMID: 27267259 DOI: 10.1080/17425255.2016.1198319] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Epilepsy may be frequently associated with psychiatric disorders and its co-existence with depression usually results in the reduced quality of life of patients with epilepsy. Also, the efficacy of antiepileptic treatment in depressed patients with epilepsy may be significantly reduced. AREAS COVERED Results of experimental studies indicate that antidepressants co-administered with antiepileptic drugs may either increase their anticonvulsant activity, remain neutral or decrease the protective action of antiepileptic drugs in models of seizures. Apart from purely pharmacodynamic interactions, pharmacokinetic mechanisms have been proven to contribute to the final outcome. We report on clinical data regarding the pharmacokinetic interactions of enzyme-inducing antiepileptic drugs with various antidepressants, whose plasma concentration may be significantly reduced. On the other hand, antidepressants (especially selective serotonin reuptake inhibitors) may influence the metabolism of antiepileptics, in many cases resulting in the elevation of plasma concentration of antiepileptic drugs. EXPERT OPINION The preclinical data may provide valuable clues on how to combine these two groups of drugs - antidepressant drugs neutral or potentiating the anticonvulsant action of antiepileptics are recommended in this regard. Avoidance of antidepressants clearly decreasing the convulsive threshold or decreasing the anticonvulsant efficacy of antiepileptic drugs (f.e. bupropion or mianserin) in patients with epilepsy is recommended.
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Affiliation(s)
- Monika Banach
- a Experimental Neuropathophysiology Unit, Department of Pathophysiology , Medical University , Lublin , Poland
| | - Monika Popławska
- a Experimental Neuropathophysiology Unit, Department of Pathophysiology , Medical University , Lublin , Poland
| | - Barbara Błaszczyk
- b Faculty of Health Sciences , High School of Economics, Law and Medical Sciences , Kielce , Poland
| | - Kinga K Borowicz
- a Experimental Neuropathophysiology Unit, Department of Pathophysiology , Medical University , Lublin , Poland
| | - Stanisław J Czuczwar
- c Department of Pathophysiology , Medical University , Lublin , Poland.,d Department of Physiopathology , Institute of Rural Health , Lublin , Poland
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Szabó CÁ, Patel M, Uteshev VV. Cerebrospinal Fluid Levels of Monoamine Metabolites in the Epileptic Baboon. ACTA ACUST UNITED AC 2015; 4. [PMID: 26924854 DOI: 10.4172/2167-6801.1000129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The baboon represents a natural model for genetic generalized epilepsy and sudden unexpected death in epilepsy (SUDEP). In this retrospective study, cerebrospinal fluid (CSF) monoamine metabolites and scalp electroencephalography (EEG) were evaluated in 263 baboons of a pedigreed colony. CSF monoamine abnormalities have been linked to reduced seizure thresholds, behavioral abnormalities and SUDEP in various animal models of epilepsy. The levels of 3-hydroxy-4-methoxyphenylglycol, 5-hydroxyindolacetic acid and homovanillic acid in CSF samples drawn from the cisterna magna were analyzed using high-performance liquid chromatography. These levels were compared between baboons with seizures (SZ), craniofacial trauma (CFT) and asymptomatic, control (CTL) baboons, between baboons with abnormal and normal EEG studies. We hypothesized that the CSF levels of major monoaminergic metabolites (i.e., dopamine, serotonin and norepinephrine) associate with the baboons' electroclinical status and thus can be used as clinical biomarkers applicable to seizures/epilepsy. However, despite apparent differences in metabolite levels between the groups, usually lower in SZ and CFT baboons and in baboons with abnormal EEG studies, we did not find any statistically significant differences using a logistic regression analysis. Significant correlations between the metabolite levels, especially between 5-HIAA and HVA, were preserved in all electroclinical groups. While we were not able to demonstrate significant differences in monoamine metabolites in relation to seizures or EEG markers of epilepsy, we cannot exclude the monoaminergic system as a potential source of pathogenesis in epilepsy and SUDEP. A prospective study evaluating serial CSF monoamine levels in baboons with recently witnessed seizures, and evaluation of abnormal expression and function of monoaminergic receptors and transporters within epilepsy-related brain regions, may impact the electroclinical status.
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Affiliation(s)
- C Ákos Szabó
- Department of Neurology and South Texas Comprehensive Epilepsy Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Mayuri Patel
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Victor V Uteshev
- Departments of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
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Fluvoxamine alleviates seizure activity and downregulates hippocampal GAP-43 expression in pentylenetetrazole-kindled mice. Behav Pharmacol 2015; 26:369-82. [DOI: 10.1097/fbp.0000000000000127] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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da Fonseca NC, Joaquim HP, Talib LL, de Vincentiis S, Gattaz WF, Valente KD. Hippocampal serotonin depletion is related to the presence of generalized tonic–clonic seizures, but not to psychiatric disorders in patients with temporal lobe epilepsy. Epilepsy Res 2015; 111:18-25. [DOI: 10.1016/j.eplepsyres.2014.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 12/18/2014] [Accepted: 12/30/2014] [Indexed: 11/16/2022]
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Kanner AM. Is depression associated with an increased risk of treatment-resistant epilepsy? Research strategies to investigate this question. Epilepsy Behav 2014; 38:3-7. [PMID: 25260238 DOI: 10.1016/j.yebeh.2014.06.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 06/24/2014] [Indexed: 11/18/2022]
Abstract
Persons with epilepsy (PWE) have a higher risk of developing depressive disorders (DDs), and people with primary DD have an increased risk of developing epilepsy. Furthermore, a lifetime history of DD has been associated with a worse response of the seizure disorder to pharmacotherapy and epilepsy surgery. The first part of this article reviews the literature of this problem with the intention of highlighting the neurobiologic pathogenic mechanisms operant in DD with a potential to facilitate the epileptogenic process and/or cortical hyperexcitability in humans and experimental animal studies of depression. They include the following: (i) a hyperactive hypothalamic-pituitary-adrenal axis and the associated structural and functional abnormalities of limbic structures, (ii) increased glutamatergic activity and decreased GABAergic and serotonergic activity, and (iii) immunologic disturbances. In the second part of this article, we suggest research strategies to test the hypothesis of whether depression worsens the course of epilepsy and identify the pathogenic mechanisms operant in this process.
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Affiliation(s)
- Andres M Kanner
- Department of Neurology, University of Miami, Miller School of Medicine, USA.
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Giorgi FS, Galanopoulou AS, Moshé SL. Sex dimorphism in seizure-controlling networks. Neurobiol Dis 2014; 72 Pt B:144-52. [PMID: 24851800 DOI: 10.1016/j.nbd.2014.05.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/02/2014] [Accepted: 05/06/2014] [Indexed: 11/27/2022] Open
Abstract
Males and females show a different predisposition to certain types of seizures in clinical studies. Animal studies have provided growing evidence for sexual dimorphism of certain brain regions, including those that control seizures. Seizures are modulated by networks involving subcortical structures, including thalamus, reticular formation nuclei, and structures belonging to the basal ganglia. In animal models, the substantia nigra pars reticulata (SNR) is the best studied of these areas, given its relevant role in the expression and control of seizures throughout development in the rat. Studies with bilateral infusions of the GABA(A) receptor agonist muscimol have identified distinct roles of the anterior or posterior rat SNR in flurothyl seizure control, that follow sex-specific maturational patterns during development. These studies indicate that (a) the regional functional compartmentalization of the SNR appears only after the third week of life, (b) only the male SNR exhibits muscimol-sensitive proconvulsant effects which, in older animals, is confined to the posterior SNR, and (c) the expression of the muscimol-sensitive anticonvulsant effects become apparent earlier in females than in males. The first three postnatal days are crucial in determining the expression of the muscimol-sensitive proconvulsant effects of the immature male SNR, depending on the gonadal hormone setting. Activation of the androgen receptors during this early period seems to be important for the formation of this proconvulsant SNR region. We describe molecular/anatomical candidates underlying these age- and sex-related differences, as derived from in vitro and in vivo experiments, as well as by [(14)C]2-deoxyglucose autoradiography. These involve sex-specific patterns in the developmental changes in the structure or physiology or GABA(A) receptors or of other subcortical structures (e.g., locus coeruleus, hippocampus) that may affect the function of seizure-controlling networks.
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Affiliation(s)
- Fillippo Sean Giorgi
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa-Pisa University Hospital, I56126 Pisa, Italy.
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Montefiore Epilepsy Management Center, and Dominick P. Purpura Department of Neuroscience, Bronx, NY, 10461, USA
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Montefiore Epilepsy Management Center, and Dominick P. Purpura Department of Neuroscience, Bronx, NY, 10461, USA; Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, 10461, USA
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Abstract
The last decade has witnessed a significant shift on our understanding of the relationship between psychiatric disorders and epilepsy. While traditionally psychiatric disorders were considered as a complication of the underlying seizure disorder, new epidemiologic data, supported by clinical and experimental research, have suggested the existence of a bidirectional relation between the two types of conditions: not only are patients with epilepsy at greater risk of experiencing a psychiatric disorder, but patients with primary psychiatric disorders are at greater risk of developing epilepsy. Do these data suggest that some of the pathogenic mechanisms operant in psychiatric comorbidities play a role in epileptogenesis? The aim of this article is to review the epidemiologic data that demonstrate that primary psychiatric disorders are more frequent in people who develop epilepsy, before the onset of the seizure disorder than among controls. The next question looks at the available data of pathogenic mechanisms of primary mood disorders and their potential for facilitating the development and/or exacerbation in the severity of epileptic seizures. Finally, we review data derived from experimental studies in animal models of depression and epilepsy that support a potential role of pathogenic mechanisms of mood disorders in the development of epileptic seizures and epileptogenesis. The data presented in this article do not yet establish conclusive evidence of a pathogenic role of psychiatric comorbidities in epileptogenesis, but raise important research questions that need to be investigated in experimental, clinical, and population-based epidemiologic research studies.
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Affiliation(s)
- Andres M Kanner
- Department of Neurology, University of Miami, Miller School of Medicine, 1120 NW, 14th Street, Room 1324, Miami, FL, 33136, USA,
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Kandratavicius L, Ruggiero RN, Hallak JE, Garcia-Cairasco N, Leite JP. Pathophysiology of mood disorders in temporal lobe epilepsy. BRAZILIAN JOURNAL OF PSYCHIATRY 2013; 34 Suppl 2:S233-45. [PMID: 23429849 DOI: 10.1016/j.rbp.2012.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE There is accumulating evidence that the limbic system is pathologically involved in cases of psychiatric comorbidities in temporal lobe epilepsy (TLE) patients. Our objective was to develop a conceptual framework describing how neuropathological, neurochemical and electrophysiological aspects might contribute to the development of psychiatric symptoms in TLE and the putative neurobiological mechanisms that cause mood disorders in this patient subgroup. METHODS In this review, clinical, experimental and neuropathological findings, as well as neurochemical features of the limbic system were examined together to enhance our understanding of the association between TLE and psychiatric comorbidities. Finally, the value of animal models in epilepsy and mood disorders was discussed. CONCLUSIONS TLE and psychiatric symptoms coexist more frequently than chance would predict. Alterations and neurotransmission disturbance among critical anatomical networks, and impaired or aberrant plastic changes might predispose patients with TLE to mood disorders. Clinical and experimental studies of the effects of seizures on behavior and electrophysiological patterns may offer a model of how limbic seizures increase the vulnerability of TLE patients to precipitants of psychiatric symptoms.
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Affiliation(s)
- Ludmyla Kandratavicius
- Department of Neurosciences and Behavior, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil.
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Kanner AM. Can neurobiological pathogenic mechanisms of depression facilitate the development of seizure disorders? Lancet Neurol 2012; 11:1093-102. [DOI: 10.1016/s1474-4422(12)70201-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Kanner AM. Psychiatric comorbidities and epilepsy: Is it the old story of the chicken and the egg? Ann Neurol 2012; 72:153-5. [DOI: 10.1002/ana.23679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Dolina S, Margalit D, Malitsky S, Pressman E, Rabinkov A. Epilepsy as a pyridoxine-dependent condition: Quantified urinary biomarkers for status evaluation and monitoring antiepileptic treatment. Med Hypotheses 2012; 79:157-64. [DOI: 10.1016/j.mehy.2012.04.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
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Citraro R, Scicchitano F, De Fazio S, Raggio R, Mainardi P, Perucca E, De Sarro G, Russo E. Preclinical activity profile of α-lactoalbumin, a whey protein rich in tryptophan, in rodent models of seizures and epilepsy. Epilepsy Res 2011; 95:60-9. [PMID: 21458955 DOI: 10.1016/j.eplepsyres.2011.02.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/18/2011] [Accepted: 02/27/2011] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the potential anticonvulsant activity of α-lactalbumin (ALAC), a whey protein rich in tryptophan (TRP) relative to other large neutral amino acids (LNAAs), in rodent models of seizures and epilepsy. METHODS The effects of ALAC administered per os were evaluated by standard protocols against audiogenic seizures in Genetic Epilepsy Prone Rats (GEPR-9 rats), maximal electroshock (MES)-induced seizures in rats, pilocarpine-induced seizures in mice, spontaneous chronic seizures in mice exposed to pilocarpine-induced status epilepticus (SE), and absence seizures in WAG/Rij rats. In some models, carbamazepine (CBZ) was included as an active control. Plasma TRP/LNAAs ratios were measured by GC-MS. RESULTS Single doses of ALAC up to 500 or 6000 mg/kg were devoid of anticonvulsant activity in all models tested. Conversely, 5- and 12-day treatment with ALAC (250-1000 mg/kg/day) in GEPR rats reduced dose-dependently seizure scores and prolonged latency to clonus onset, with full persistence of the effect for up to 12h. ALAC (125-500 mg/kg/day for 15 days) protected against seizures induced by 250 mg/kg pilocarpine, but was less effective against higher pilocarpine doses. Similarly to CBZ, ALAC (125-500 mg/kg/day for 15 days) was also effective against spontaneous seizures in the post-pilocarpine SE model. ALAC (up to 6000 mg/kg/day for 12 days) did not prevent MES-induced seizures, although it reduced the duration of tonic extension at doses between 250 and 1000 mg/kg/day. Absence seizures in WAG/Rij rats were not significantly affected by ALAC. Plasma TRP/LNAAS ratios increased 2- to 3-fold after dosing with ALAC (250 mg/kg/day) for 7 and 14 days, respectively. CONCLUSIONS ALAC exerts significant protective activity against seizures in animal models, the effect being especially prominent against audiogenic seizures in GEPR-9 rats, seizures induced by low-dose pilocarpine in mice, and spontaneous seizures in mice exposed to pilocarpine-induced SE. This action is likely to be mediated by increased availability of TRP in the brain, with a consequent increase in 5-HT mediated transmission.
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Affiliation(s)
- Rita Citraro
- Chair of Pharmacology, Department of Experimental and Clinical Medicine, School of Medicine, University Magna Graecia of Catanzaro, Via T. Campanella 115, Catanzaro, Italy
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Richerson GB, Buchanan GF. The serotonin axis: Shared mechanisms in seizures, depression, and SUDEP. Epilepsia 2011; 52 Suppl 1:28-38. [PMID: 21214537 DOI: 10.1111/j.1528-1167.2010.02908.x] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There is a growing appreciation that patients with seizures are also affected by a number of comorbid conditions, including an increase in prevalence of depression (Kanner, 2009), sleep apnea (Chihorek et al., 2007), and sudden death (Ryvlin et al., 2006; Tomson et al., 2008). The mechanisms responsible for these associations are unclear. Herein we discuss the possibility that underlying pathology in the serotonin (5-HT) system of patients with epilepsy lowers the threshold for seizures, while also increasing the risk of depression and sudden death. We propose that postictal dysfunction of 5-HT neurons causes depression of breathing and arousal in some epilepsy patients, and this can lead to sudden unexpected death in epilepsy (SUDEP). We further draw parallels between SUDEP and sudden infant death syndrome (SIDS), which may share pathophysiologic mechanisms, and which have both been linked to defects in the 5-HT system.
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Hecimovic H, Stefulj J, Cicin-Sain L, Demarin V, Jernej B. Association of serotonin transporter promoter (5-HTTLPR) and intron 2 (VNTR-2) polymorphisms with treatment response in temporal lobe epilepsy. Epilepsy Res 2010; 91:35-8. [PMID: 20655708 DOI: 10.1016/j.eplepsyres.2010.06.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/25/2010] [Accepted: 06/20/2010] [Indexed: 11/24/2022]
Abstract
PURPOSE Temporal lobe epilepsy (TLE) is the most common epilepsy and about 30% of patients have poorly controlled seizures. Neurobiology underlying responsiveness to medical treatment in TLE patients is unclear and there are currently no biological tests to predict course of the disease. Animal and human studies repeatedly suggested serotonergic dysfunction in subjects with TLE. We investigated association of serotonin transporter (5-HTT) gene polymorphisms with medical treatment response in patients with TLE. METHODS We analyzed 5-HTT gene linked polymorphic region (5-HTTLPR) in promoter and variable number of tandem repeats in the second intron of the 5-HTT gene (VNTR-2) in 101 consecutive subjects with TLE. RESULTS TLE patients with the combination of transcriptionally more efficient genotypes, i.e. 5-HTTLPR L/L and VNTR-2 12/12, had increased seizure refractoriness to antiepileptic medication therapy and shorter periods of seizure freedom, than subjects with other combinations of the 5-HTT genotypes. There were no other clinical or demographic differences among patient groups based on the 5-HTT genotypes. CONCLUSION Combination of the 5-HTT genotypes linked with higher 5-HTT gene expression was found to be associated with worse response to optimal drug therapy. Further studies should determine potential role of this 5-HTT genotype polymorphism in epileptogenesis.
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Affiliation(s)
- Hrvoje Hecimovic
- Zagreb Epilepsy Center, Department of Neurology, University Hospital, Vinogradska 29, HR-10000 Zagreb, Croatia.
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Kanner AM. Depression and Epilepsy: A Review of Multiple Facets of Their Close Relation. Neurol Clin 2009; 27:865-880. [DOI: 10.1016/j.ncl.2009.08.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Kanner AM. Psychiatric issues in epilepsy: the complex relation of mood, anxiety disorders, and epilepsy. Epilepsy Behav 2009; 15:83-7. [PMID: 19245845 DOI: 10.1016/j.yebeh.2009.02.034] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Accepted: 02/19/2009] [Indexed: 11/17/2022]
Abstract
The comorbid psychiatric disorders in patients with epilepsy have been neglected for a long time. And yet, epidemiological studies have demonstrated a relatively high prevalence of mood, anxiety, and attention deficit hyperactivity disorders. Furthermore, the relation between psychiatric disorders and epilepsy is complex, as illustrated by the relation between mood disorders and epilepsy. The aim of this article is to summarize the most relevant data on the complex relation between mood disorders and epilepsy, which extends to anxiety disorders and which can be explained by the existence of common pathogenic mechanisms shared by these three conditions. The significance of such a relation is not only theoretical, but has a marked impact on the response to pharmacological and surgical treatment of seizure disorders.
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Affiliation(s)
- Andres M Kanner
- Department of Neurological Sciences, Rush Medical College, 1653 West Congress Parkway, Chicago, IL, USA.
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Mirski MA, Ziai WC, Chiang J, Hinich M, Sherman D. Anticonvulsant serotonergic and deep brain stimulation in anterior thalamus. Seizure 2009; 18:64-70. [DOI: 10.1016/j.seizure.2008.06.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2007] [Accepted: 06/20/2008] [Indexed: 11/15/2022] Open
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García-Morales I, de la Peña Mayor P, Kanner AM. Psychiatric Comorbidities in Epilepsy: Identification and Treatment. Neurologist 2008; 14:S15-25. [DOI: 10.1097/01.nrl.0000340788.07672.51] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kanner AM. Mood disorder and epilepsy: a neurobiologic perspective of their relationship. DIALOGUES IN CLINICAL NEUROSCIENCE 2008. [PMID: 18472483 PMCID: PMC3181864 DOI: 10.31887/dcns.2008.10.1/amkanner] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mood disorders are the most frequent psychiatric comorbidity in epilepsy, and in particular in temporal lobe epilepsy. For a long time, depressive disorders were considered to be the expression of a reactive process to the obstacles of a life with epilepsy Data obtained in the last two decades, however, have demonstrated biochemical, neuropathoiogical, and neurophysioiogic changes mediating the development of mood disorders, which in fact can be tested in animal models. Furthermore, there is also evidence that mood disorders and epilepsy have a complex relationship which is bidirectional; that is, not only are patients with epilepsy at greater risk of developing depression, but patients with depression have a higher risk of developing epilepsy. Such a relationship can only be explained by the existence of common pathogenic mechanisms that are operant in both conditions. These include changes in neurotransmitters, such as serotonin, norepinephrine, glutamate, and γ-aminobutyric acid. Such a bidirectional relationship also appears to have important clinical consequences. Indeed, patients with a history of mood disorders are twice as likely to develop pharmacoresistant epilepsy as those without such a history. These data are reviewed in this article.
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Affiliation(s)
- Andres M Kanner
- Rush Medical College, Rush University Medical Center, Chicago, Illinois 60612, USA.
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Hasler G, Bonwetsch R, Giovacchini G, Toczek MT, Bagic A, Luckenbaugh DA, Drevets WC, Theodore WH. 5-HT1A receptor binding in temporal lobe epilepsy patients with and without major depression. Biol Psychiatry 2007; 62:1258-64. [PMID: 17588547 PMCID: PMC2170875 DOI: 10.1016/j.biopsych.2007.02.015] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/08/2007] [Accepted: 02/10/2007] [Indexed: 11/17/2022]
Abstract
BACKGROUND Major depressive disorder (MDD) is the most common comorbid psychiatric condition associated with temporal lobe epilepsy (TLE). Preclinical and clinical studies suggest that 5-HT(1A) receptors play a role in the pathophysiology of both TLE and MDD. There is preliminary evidence for an association between decreased 5-HT(1A) receptor binding in limbic brain areas and affective symptoms in TLE patients. The objective of this study was to compare 5-HT(1A) receptor binding between TLE patients with and without MDD. For the first time, 5-HT(1A) receptor binding was measured in a sample large enough to permit sensitive comparisons between TLE patients with and without comorbid MDD diagnosed by clinical and structured psychiatric interviews. METHODS Thirty-seven epilepsy patients with temporal lobe foci confirmed by ictal video-electroencephalogram (EEG) monitoring were recruited from the Clinical Epilepsy Section, National Institute of Neurological Disorders and Stroke. We performed interictal positron emission tomography scanning, with [(18)F]FCWAY, a fluorinated derivative of WAY100635, on a GE Medical Systems (Waukesha, Wisconsin) Advance scanner with continuous EEG monitoring. The 5-HT(1A) receptor binding was estimated by partial volume-corrected [(18)F]FCWAY V/f(1) values. RESULTS In addition to decreased 5-HT(1A) receptor binding in the epileptic focus itself, comorbid MDD was associated with a significantly more pronounced reduction in 5-HT(1A) receptor binding in TLE patients, extending into non-lesional limbic brain areas outside the epileptic focus. Focus side and the presence of mesial temporal sclerosis were not associated with the presence of comorbid depression. CONCLUSIONS Reductions in 5-HT(1A) receptor binding might help elucidate the neurobiological mechanisms underlying the TLE-MDD comorbidity.
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Affiliation(s)
- Gregor Hasler
- Department of Psychiatry, University Hospital, Culmannstrasse 8, Zürich, Switzerland.
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Abstract
PURPOSE OF REVIEW In this review we discuss recent advances in the neuroimaging of patients with tuberous sclerosis complex (TSC), highlighting its application in improving clinical management, particularly in the case of intractable epilepsy. RECENT FINDINGS Progress in structural and functional imaging has led to further characterization of the brain lesions in TSC. New magnetic resonance imaging techniques that can delineate the extent of structural brain abnormalities in TSC have been developed. Diffusion tensor imaging unveils the microstructural abnormalities of the brain lesions and of the morphologically normal appearing white matter in TSC. It can potentially identify the epileptogenic zone. Positron emission tomography scanning with 2-deoxy-2-[18F]fluoro-D-glucose can assess the full extent of functional brain abnormalities in TSC. The use of alpha [11C] methyl-L-tryptophan positron emission tomography scanning has proven to be a useful tool in the identification of epileptogenic tubers and has improved the outcome of surgery for epilepsy in TSC. SUMMARY Major advances of neuroimaging in TSC have shown evidence of widespread structural and functional brain abnormalities. In TSC patients with intractable epilepsy, new neuroimaging modalities can now provide an accurate assessment of the epileptogenic zone, thereby permitting improved identification of patients who can have good seizure outcome following surgery for epilepsy.
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Affiliation(s)
- Aimee F Luat
- Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit, Michigan 48201, USA
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Abstract
Depression and Attempted Suicide as Risk Factors for Incident Unprovoked Seizures and Epilepsy Hesdorffer DC, Hauser WA, Olaffson E, Ludvigsson P, Kjartansson O Ann Neurol 2006;59:35–41. Major depression has been shown to increase the risk for development of epilepsy, but prior studies have not evaluated whether this is due to specific symptoms of depression. We conducted a population-based case-control study of all newly diagnosed unprovoked seizures among Icelandic children and adults aged 10 years and older to test the hypothesis that major depression is a risk factor for developing unprovoked seizure and epilepsy, and to address whether specific symptoms of depression account for this increased risk. Cases were matched to the next two same sex births from the population registry. Using standardized interviews, we ascertained symptoms of major depression to make a Diagnostic and Statistical Manual, Fourth Edition (DSM-IV) diagnosis. A history of major depression was 1.7-fold more common among cases than among controls (95% confidence interval, 1.1–2.7). A history of attempted suicide was 5.1-fold more common among cases than among controls (95% confidence interval, 2.2–11.5). Attempted suicide increased seizure risk even after adjusting for age, sex, cumulative alcohol intake, and major depression or number of symptoms of depression. Major depression and attempted suicide independently increase the risk for unprovoked seizure. These data suggest that depression and suicide attempt may be due to different underlying neurochemical pathways, each of which is important in the development of epilepsy.
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Richman A, Heinrichs SC. Seizure prophylaxis in an animal model of epilepsy by dietary fluoxetine supplementation. Epilepsy Res 2007; 74:19-27. [PMID: 17215106 DOI: 10.1016/j.eplepsyres.2006.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2006] [Revised: 11/20/2006] [Accepted: 11/30/2006] [Indexed: 10/23/2022]
Abstract
Clinical and animal model evidence suggests that selective serotonin reuptake inhibitors (SSRIs) act as anticonvulsants. The present studies tested the possibility that the El mouse model of genetically predisposed/handling-triggered epilepsy would exhibit fewer seizures following SSRI treatment via dietary fluoxetine adulteration. In particular, potential bioenergetic and neural mechanisms for anticonvulsant efficacy of fluoxetine were explored using food intake/body weight monitoring and quantification of brain serotonin transporter protein. El mice consuming a chow diet ad libitum or yoked in quantity to fluoxetine diet intake exhibited seizure incidence of 40% in response to tail-suspension handling, whereas seizures were abolished (0%) among El mice consuming a fluoxetine-adultered diet over 7 days. A 3 day period of fluoxetine administration was insufficient to exert anticonvulsant efficacy and all treatment groups exhibited the same circadian locomotor activity patterns at the time of seizure susceptibility testing. Bioenergetic factors could not account for the anticonvulsant efficacy of fluoxetine since yoked diet controls with matched food intake, body weight change and blood glucose levels exhibited the same 40% seizure incidence as ad libitum chow controls. Importantly, the 7 day period of dietary fluoxetine exposure was effective in selectively reducing cell density in the parietal cortex and increasing serotonin transporter protein content in the nucleus accumbens. Taken together, these results suggest that dietary fluoxetine supplementation abolishes handling-induced seizure susceptibility in El mice via a neural remodeling mechanism independent of energy balance.
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Affiliation(s)
- Alyssa Richman
- Department of Psychology, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, United States
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Abstract
Depression is the most frequent psychiatric comorbidity in patients with epilepsy. By the same token, patients with depression are at higher risk of developing epilepsy than are controls. Such bidirectional relations raise the question of whether both disorders share common pathogenic mechanisms, presenting with common neurotransmitter abnormalities and involvement of the same neuroanatomic structures. In this article, some of the available data in support of this hypothesis are reviewed.
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Affiliation(s)
- Andres M Kanner
- Department of Neurological Sciences, Rush Medical College, Rush Epilepsy Center, Rush University Medical Center, Chicago, Illinois, USA
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Compan V, Zhou M, Grailhe R, Gazzara RA, Martin R, Gingrich J, Dumuis A, Brunner D, Bockaert J, Hen R. Attenuated response to stress and novelty and hypersensitivity to seizures in 5-HT4 receptor knock-out mice. J Neurosci 2004; 24:412-9. [PMID: 14724239 PMCID: PMC6729986 DOI: 10.1523/jneurosci.2806-03.2004] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
To study the functions of 5-HT4 receptors, a null mutation was engineered in the corresponding gene. 5-HT4 receptor knock-out mice displayed normal feeding and motor behaviors in baseline conditions but abnormal feeding and locomotor behavior in response to stress and novelty. Specifically, stress-induced hypophagia and novelty-induced exploratory activity were attenuated in the knock-out mice. In addition, pentylenetetrazol-induced convulsive responses were enhanced in the knock-out mice, suggesting an increase in neuronal network excitability. These results provide the first example of a genetic deficit that disrupts the ability of stress to reduce feeding and body weight and suggest that 5-HT4 receptors may be involved in stress-induced anorexia and seizure susceptibility.
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Affiliation(s)
- Valérie Compan
- Unité Propre de Recherche Centre National de la Recherche Scientifique 2580, Génomique fonctionnelle, Montpellier 34094, France.
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Abstract
Many treatments for the epilepsies and affective disorder share the properties of seizure suppression and mood stabilization. Moreover, affective disorders and the epilepsies appear to share partially similar pathogenic mechanisms. A component of the shared predisposition appears to arise from noradrenergic and serotonergic deficits. Increasing evidence supports the hypothesis that noradrenergic and/or serotonergic elevation is a mechanism of therapeutic benefit shared by most antidepressants and many antiepileptic medications. Medication induced alterations in GABAergic, glutamatergic, and CRH (corticotropin releasing hormone) containing neurons may also contribute to the shared therapeutic properties of antidepressant and antiepileptic medications.
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Affiliation(s)
- Phillip C Jobe
- Department of Biomedical and Therapeutic Sciences, University of Illinois College of Medicine, PO Box 1649, Peoria, Illinois 61656-1649, USA.
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Abstract
Affective disorders and the epilepsies appear to share partially similar pathogenic mechanisms. Predisposition to both disorders is determined genetically and experientially. A component of the shared predisposition appears to arise from noradrenergic and serotonergic deficits. Shared GABAergic deficits coupled with CRHergic and glutamatergic excesses may trigger and maintain seizures as well as dysfunctional affective episodes, albeit via dissimilar neuronal interplay.
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Affiliation(s)
- Phillip C Jobe
- Department of Biomedical and Therapeutic Sciences, University of Illinois College of Medicine at Peoria, P.O. Box 1649, Peoria, IL 61656, USA.
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Scarlatelli-Lima AV, Magalhães LHM, Doretto MC, Moraes MFD. Assessment of the seizure susceptibility of Wistar Audiogenic rat to electroshock, pentyleneterazole and pilocarpine. Brain Res 2003; 960:184-9. [PMID: 12505671 DOI: 10.1016/s0006-8993(02)03831-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This work evaluates the seizure susceptibility of nai;ve female Wistar Audiogenic rats (WARs), a genetic model of reflex epilepsy in which seizures are induced by high-intensity sound stimulation (120 dB SPL), to other pro-convulsive stimuli: transauricular electroshock (ES), pentylenetetrazole (PTZ) and pilocarpine (PILO). Normal Wistar rats from the main breeding stock of the Institute of Biological Sciences, UFMG were taken as controls. Electroshock seizures were induced through a pair of ear-clip electrodes (10 mA, at a frequency of 60 Hz, applied for 1 s). In order to test WAR susceptibility to chemically induced seizures, animals were treated either with PTZ (37.5 mg/kg i.p.) or PILO (200, 270 and 300 mg/kg i.p.). Seizure severity was evaluated by appropriate behavioral severity index scales (SI) specific to each epilepsy model and tested for statistical significance using the non-parametric Mann-Whitney Rank Sum test. Results show a significantly greater susceptibility of WARs for ES (SI(WAR)=3+/-3/3, SI(Wistar)=1+/-1/1; median+/-interquartile range 25%/75%, P<0.01) and PTZ (SI(WAR)=4+/-4/4, SI(Wistar)=1+/-1/4; median+/-interquartile range 25%/75%, P<0.02), as indicated by significantly higher SI scores and shorter latencies for seizure onset (T(WAR)=71+/-7 s, T(Wistar)=94+/-8 s; P<0.05 Student t-test, mean+/-S.E.M.). Although PILO also caused higher SI scores in WARs (WAR(200 mg)=1+/-1/1, Wistar(200 mg)=1+/-1/1; WAR(270 mg)=1.5+/-1/2, Wistar(270 mg)=1+/-1/1.25; WAR(300 mg)=9+/-1/9, Wistar(300 mg)=4+/-1.5/7.5; median+/-interquartile range 25%/75%), statistically significant differences were not observed. In conclusion, our results show that WARs have an inherited broader predisposition for seizures.
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Affiliation(s)
- A V Scarlatelli-Lima
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Av Antonio Carlos 6627, Campus Pampulha, CEP 31270-901, Belo Horizonte, MG, Brazil
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Sander T, Berlin W, Ostapowicz A, Samochowiec J, Gscheidel N, Hoehe MR. Variation of the genes encoding the human glutamate EAAT2, serotonin and dopamine transporters and Susceptibility to idiopathic generalized epilepsy. Epilepsy Res 2000; 41:75-81. [PMID: 10924870 DOI: 10.1016/s0920-1211(00)00120-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Several interacting genetic factors are likely to be involved in the epileptogenesis of idiopathic generalized epilepsies (IGE). Neurotransmitter transporters play a central role in the fine tuning of neurotransmission by removal of released neurotransmitters from the synaptic cleft. The present association study tested the hypotheses that variation of the genes encoding neurotransmitter transporters confers susceptibility to IGE. The genotypes of 133 German IGE subjects and 223 ethnically matched controls were assessed for DNA polymorphisms of genes encoding the glutamate (EAAT2), the serotonin (SERT), and dopamine (DAT) transporters. To increase genetic homogeneity, a subgroup of 76 patients with idiopathic absence epilepsy (IAE) was analyzed separately. We found no evidence for an allelic association of either the silent G603A substitution polymorphism in exon 5 of the EAAT2 gene or the regulatory promoter polymorphism of the SERT gene with either IGE or IAE. The frequency of the nine-copy allele of the 40 base pair repeat polymorphism in the 3' un pop popd region of the DAT gene was significantly increased in the IGE patients (chi2 = 4.11, degrees of freedom (d.f.) = 1, P = 0.043) and, in particular, in the IAE patients (chi2 = 7.81, d.f. = 1, P = 0.005) compared with the controls. The present findings strengthen previous evidence that genetic variation of the DAT gene modulates neuronal network excitability and contributes to the epileptogenesis of IAE.
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Affiliation(s)
- T Sander
- Department of Neurology, University Hospital Charité, Berlin, Germany.
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Abstract
Several lines of evidence suggest that norepinephrine (NE) can modulate seizure activity. However, the experimental methods used in the past cannot exclude the possible role of other neurotransmitters coreleased with NE from noradrenergic terminals. We have assessed the seizure susceptibility of genetically engineered mice that lack NE. Seizure susceptibility was determined in the dopamine beta-hydroxylase null mutant (Dbh -/-) mouse using four different convulsant stimuli: 2,2,2-trifluroethyl ether (flurothyl), pentylenetetrazol (PTZ), kainic acid, and high-decibel sound. Dbh -/- mice demonstrated enhanced susceptibility (i.e., lower threshold) compared with littermate heterozygous (Dbh +/-) controls to flurothyl, PTZ, kainic acid, and audiogenic seizures and enhanced sensitivity (i.e., seizure severity and mortality) to flurothyl, PTZ, and kainic acid. c-Fos mRNA expression in the cortex, hippocampus (CA1 and CA3), and amygdala was increased in Dbh -/- mice in association with flurothyl-induced seizures. Enhanced seizure susceptibility to flurothyl and increased seizure-induced c-fos mRNA expression were reversed by pretreatment with L-threo-3, 4-dihydroxyphenylserine, which partially restores the NE content in Dbh -/- mice. These genetically engineered mice confirm unambiguously the potent effects of the noradrenergic system in modulating epileptogenicity and illustrate the unique opportunity offered by Dbh -/- mice for elucidating the pathways through which NE can regulate seizure activity.
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Samochowiec J, Smolka M, Winterer G, Rommelspacher H, Schmidt LG, Sander T. Association analysis between a Cys23ser substitution polymorphism of the human 5-HT2c receptor gene and neuronal hyperexcitability. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-8628(19990416)88:2<126::aid-ajmg6>3.0.co;2-m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Abstract
Serotonin 5-HT2C receptor null mutant mice were generated to assess the contribution of this receptor to the actions of serotonin. Mutant mice displayed both an epilepsy and obesity phenotype. The epilepsy syndrome was characterized by spontaneous seizures, lowered seizure threshold, enhanced seizure propagation and sound-induced seizure susceptibility. These findings implicate 5-HT2C receptors in the regulation of neuronal network excitability. It was also observed that body weight and adipose tissue deposition were elevated in adult mutant mice relative to their wild type littermates. Paired-feeding studies suggest that the obesity syndrome is a result of increased food intake. In addition, mutants displayed reduced sensitivity to the appetite suppressant actions of non-specific serotonergic agonists. These studies establish a role for 5-HT2C receptors in the serotonergic regulation of body weight and food intake.
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Affiliation(s)
- L K Heisler
- Department of Psychiatry, University of California at San Francisco 94143, USA
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Dailey JW, Reith ME, Steidley KR, Milbrandt JC, Jobe PC. Carbamazepine-induced release of serotonin from rat hippocampus in vitro. Epilepsia 1998; 39:1054-63. [PMID: 9776325 DOI: 10.1111/j.1528-1157.1998.tb01290.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE Carbamazepine is one of several antiepileptic drugs (AEDs) that release the inhibitory neurotransmitter serotonin as part of their pharmacodynamic action on brain neurons. We undertook this study to investigate the cellular processes by which carbamazepine (CBZ) releases serotonin from brain tissue. METHODS Tissue slices were prepared from hippocampi of Sprague-Dawley rats. These hippocampal slices were preincubated in vitro in a buffer so that neurons within the slice would take up tritium-labeled serotonin. Subsequently the slices were superfused with buffer containing CBZ or other chemicals (or both) that increase the overflow of serotonin radioactivity. RESULTS Carbamazepine produced a concentration-dependent (50, 125, 250, or 500 microM) increase in basal overflow of serotonin radioactivity from superfused rat hippocampal slices in vitro. In contrast, these concentrations did not alter potassium-stimulated release, suggesting that the CBZ-induced release does not depend on depolarization or exocytosis. Blockade of the neuronal membrane serotonin transporter by fluoxetine (1 microM) or citalopram (2 microM) did not alter overflow of serotonin radioactivity produced by 250 microM CBZ. p-chloramphetamine (10 microM) produced a substantial increase in overflow of serotonin radioactivity, and this effect appears to be antagonized by 250 microM CBZ. Uptake of [3H]-labeled serotonin into hippocampal synaptosomes was inhibited by CBZ with a median inhibitory concentration (IC50) of 511+/-33 microM and a Hill coefficient of 0.87+/-0.11, suggesting competitive inhibition of uptake by CBZ. CONCLUSIONS We conclude that CBZ (a) releases serotonin from hippocampal slices independent of exocytosis and by a mechanism not involving the neuronal membrane serotonin transporter, and (b) at high enough concentration, blocks the neuronal serotonin transporter.
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Affiliation(s)
- J W Dailey
- Department of Biomedical and Therapeutic Sciences, University of Illinois College of Medicine, Peoria 61656, USA
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Lu KT, Gean PW. Endogenous serotonin inhibits epileptiform activity in rat hippocampal CA1 neurons via 5-hydroxytryptamine1A receptor activation. Neuroscience 1998; 86:729-37. [PMID: 9692713 DOI: 10.1016/s0306-4522(98)00106-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The modulatory effects of endogenous serotonin on the synaptic transmission and epileptiform activity were studied in the rat hippocampus with the use of extracellular and intracellular recording techniques. Field excitatory postsynaptic potential was reversibly depressed by serotonin in a concentration-dependent manner. Intracellular recordings revealed that serotonin-mediated synaptic depression was unaffected by extracellular Ba2+ or intracellular application of Cs+ while the postsynaptic hyperpolarizing effect was completely blocked. Epileptiform activity induced by picrotoxin (50 microM), a GABA(A) receptor antagonist, was also dose-dependently suppressed by serotonin. The antiepileptic effect was mimicked by 5-hydroxytryptamine1A agonist and was blocked by 5-hydroxytryptamine1A antagonists. 5-Hydroxytryptamine2 antagonist had no effect on the modulation. Similarly, fluoxetine, a selective serotonin re-uptake blocker, potently inhibited the epileptiform activity and this effect was blocked by 5-hydroxytryptamine1A receptor antagonist. Depletion of endogenous serotonin by pretreating the slices with p-chloroamphetamine completely prevented the antiepileptic action of fluoxetine, without modifying the action of serotonin in the same cells. These results suggest that the antiepileptic action of fluoxetine is due to an enhancement of endogenous serotonin which in turn is mediated by 5-hydroxytryptamine1A receptor. Endogenous serotonin transmission in the hippocampus is therefore capable of limiting the development and propagation of seizure activity.
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Affiliation(s)
- K T Lu
- Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan City, Taiwan
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