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Rocchetti J, Fasano C, Dal-Bo G, Guma E, El Mestikawy S, Wong TP, Fakhfouri G, Giros B. Persistent extrasynaptic hyperdopaminergia in the mouse hippocampus induces plasticity and recognition memory deficits reversed by the atypical antipsychotic sulpiride. PLoS One 2023; 18:e0289770. [PMID: 37624765 PMCID: PMC10456148 DOI: 10.1371/journal.pone.0289770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023] Open
Abstract
Evidence suggests that subcortical hyperdopaminergia alters cognitive function in schizophrenia and antipsychotic drugs (APD) fail at rescuing cognitive deficits in patients. In a previous study, we showed that blocking D2 dopamine receptors (D2R), a core action of APD, led to profound reshaping of mesohippocampal fibers, deficits in synaptic transmission and impairments in learning and memory in the mouse hippocampus (HP). However, it is currently unknown how excessive dopamine affects HP-related cognitive functions, and how APD would impact HP functions in such a state. After verifying the presence of DAT-positive neuronal projections in the ventral (temporal), but not in the dorsal (septal), part of the HP, GBR12935, a blocker of dopamine transporter (DAT), was infused in the CA1 of adult C57Bl/6 mice to produce local hyperdopaminergia. Chronic GBR12935 infusion in temporal CA1 induced a mild learning impairment in the Morris Water Maze and abolished long-term recognition memory in novel-object (NORT) and object-place recognition tasks (OPRT). Deficits were accompanied by a significant decrease in DAT+ mesohippocampal fibers. Intrahippocampal or systemic treatment with sulpiride during GBR infusions improved the NORT deficit but not that of OPRT. In vitro application of GBR on hippocampal slices abolished long-term depression (LTD) of fEPSP in temporal CA1. LTD was rescued by co-application with sulpiride. In conclusion, chronic DAT blockade in temporal CA1 profoundly altered mesohippocampal modulation of hippocampal functions. Contrary to previous observations in normodopaminergic mice, antagonising D2Rs was beneficial for cognitive functions in the context of hippocampal hyperdopaminergia.
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Affiliation(s)
- Jill Rocchetti
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
| | - Caroline Fasano
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
| | - Gregory Dal-Bo
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
| | - Elisa Guma
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
| | - Salah El Mestikawy
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
- Sorbonne Université, INSERM, CNRS, NPS – IBPS, Paris, France
| | - Tak-Pan Wong
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
| | - Gohar Fakhfouri
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
| | - Bruno Giros
- Department of Psychiatry, Douglas Hospital, Mc Gill University, Montreal, Québec, Canada
- Université Paris-Cité, INCC UMR 8002, CNRS, Paris, France
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Vavers E, Zvejniece L, Dambrova M. Sigma-1 receptor and seizures. Pharmacol Res 2023; 191:106771. [PMID: 37068533 PMCID: PMC10176040 DOI: 10.1016/j.phrs.2023.106771] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/03/2023] [Accepted: 04/13/2023] [Indexed: 04/19/2023]
Abstract
Over the last decade, sigma-1 receptor (Sig1R) has been recognized as a valid target for the treatment of seizure disorders and seizure-related comorbidities. Clinical trials with Sig1R ligands are underway testing therapies for the treatment of drug-resistant seizures, developmental and epileptic encephalopathies, and photosensitive epilepsy. However, the direct molecular mechanism by which Sig1R modulates seizures and the balance between excitatory and inhibitory pathways has not been fully elucidated. This review article aims to summarize existing knowledge of Sig1R and its involvement in seizures by focusing on the evidence obtained from Sig1R knockout animals and the anti-seizure effects of Sig1R ligands. In addition, this review article includes a discussion of the advantages and disadvantages of the use of existing compounds and describes the challenges and future perspectives on the use of Sig1R as a target for the treatment of seizure disorders.
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Affiliation(s)
- Edijs Vavers
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia; University of Tartu, Faculty of Science and Technology, Institute of Chemistry, Ravila 14a, 50411, Tartu, Estonia.
| | - Liga Zvejniece
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia
| | - Maija Dambrova
- Latvian Institute of Organic Synthesis, Laboratory of Pharmaceutical Pharmacology, Aizkraukles 21, LV-1006, Riga, Latvia; Riga Stradiņš University, Faculty of Pharmacy, Konsula 21, LV-1007, Riga, Latvia
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3
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Tallarico M, Pisano M, Leo A, Russo E, Citraro R, De Sarro G. Antidepressant Drugs for Seizures and Epilepsy: Where do we Stand? Curr Neuropharmacol 2023; 21:1691-1713. [PMID: 35761500 PMCID: PMC10514547 DOI: 10.2174/1570159x20666220627160048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 06/13/2022] [Accepted: 06/18/2022] [Indexed: 11/22/2022] Open
Abstract
People with epilepsy (PWE) are more likely to develop depression and both these complex chronic diseases greatly affect health-related quality of life (QOL). This comorbidity contributes to the deterioration of the QOL further than increasing the severity of epilepsy worsening prognosis. Strong scientific evidence suggests the presence of shared pathogenic mechanisms. The correct identification and management of these factors are crucial in order to improve patients' QOL. This review article discusses recent original research on the most common pathogenic mechanisms of depression in PWE and highlights the effects of antidepressant drugs (ADs) against seizures in PWE and animal models of seizures and epilepsy. Newer ADs, such as selective serotonin reuptake inhibitors (SRRI) or serotonin-noradrenaline reuptake inhibitors (SNRI), particularly sertraline, citalopram, mirtazapine, reboxetine, paroxetine, fluoxetine, escitalopram, fluvoxamine, venlafaxine, duloxetine may lead to improvements in epilepsy severity whereas the use of older tricyclic antidepressant (TCAs) can increase the occurrence of seizures. Most of the data demonstrate the acute effects of ADs in animal models of epilepsy while there is a limited number of studies about the chronic antidepressant effects in epilepsy and epileptogenesis or on clinical efficacy. Much longer treatments are needed in order to validate the effectiveness of these new alternatives in the treatment and the development of epilepsy, while further clinical studies with appropriate protocols are warranted in order to understand the real potential contribution of these drugs in the management of PWE (besides their effects on mood).
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Affiliation(s)
- Martina Tallarico
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Maria Pisano
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Antonio Leo
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Emilio Russo
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Rita Citraro
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Giovambattista De Sarro
- System and Applied Pharmacology, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, Catanzaro, Italy
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4
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Marinho AMDN, Lobão-Soares B, Targino HAS, Vasconcellos YJF, Guarnieri R, Carlotti CG. Decreased hippocampal serotonin 5HT 1A expression in mesial temporal lobe of epilepsy patients. Epilepsy Behav 2022; 129:108574. [PMID: 35189481 DOI: 10.1016/j.yebeh.2022.108574] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) is a surgically remediable epilepsy with a relatively high prevalence and psychiatric comorbidities. Depressive disorders may occur in up to 25% of MTLE-HS patients suggesting a common molecular mechanism underlying both conditions. OBJECTIVE To compare the gene expression comprising serotonin 5HT1A and 5HT2A, noradrenaline (NA) ADRA1A, and ADRA2A receptors in the hippocampus of MTLE-HS patients with and without major depression. METHODS A cross-sectional study allocated 31 patients in three groups: MTLE-HS without psychiatric diagnosis (MTLE-HS group), MTLE-HS with major depression (MTLE-HS-D group) and a control group consisting of healthy volunteers without any neurological or psychiatric disorders. Demographic and clinical characteristics were compared among groups. Gene expression of receptors were analyzed using general linear mixed models (GLMM), with an unstructured matrix, normal link. RESULTS The three groups showed a similar distribution regarding age, gender (p > 0.16), history of initial precipitating injury, family history of epilepsy, monthly frequency of seizures, side of hippocampal sclerosis, interictal spike distribution and anti-seizure medications did not differ between MTLE-HS and MTLE-HS-D groups (p > 0.05). We observed a greater expression of the 5HT1A receptor in the control group when compared to the MTLE-HS (P = .004) and MTLE-HS-D (P = .007). Nevertheless, we did not observe any difference when MTLE-HS and MTLE-HS-D groups were compared to the controls for the ADRA1A (P = .931; P = .931), ADRA2A (P = .120; P = .121) and 5HT2A (P = .638; P = .318, respectively) gene expression. CONCLUSION Mesial temporal lobe epilepsy related to hippocampal sclerosis and MTLE-HS-D patients showed a lowered expression of the 5HT1A receptors when compared with the controls adjusted for age and schooling. Data suggest that temporal lobe epilepsy plasticity may affect serotonin receptors, which may lead to more frequent cases of major depression in this population. More studies comprising wider samples are necessary to confirm these results; they also should investigate serotonin reuptake drugs as an adjuvant therapeutic option for MTLE-HS disorder.
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Affiliation(s)
| | - Bruno Lobão-Soares
- Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte (DBF - UFRN), Brazil.
| | | | | | | | - Carlos Gilberto Carlotti
- Department of Surgery, Faculty of Medicine of Ribeirão Preto, Universidade de São Paulo, (FMRP-USP), Brazil
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Bombardi C, Grandis A, Pivac N, Sagud M, Lucas G, Chagraoui A, Lemaire-Mayo V, De Deurwaerdère P, Di Giovanni G. Serotonin modulation of hippocampal functions: From anatomy to neurotherapeutics. PROGRESS IN BRAIN RESEARCH 2021; 261:83-158. [PMID: 33785139 DOI: 10.1016/bs.pbr.2021.01.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The hippocampal region receives a dense serotoninergic innervation originating from both medial and dorsal raphe nuclei. This innervation regulates hippocampal activity through the activation of distinct receptor families that are expressed in excitatory and inhibitory neurons, terminals of several afferent neurotransmitter systems, and glial cells. Preclinical and clinical studies indicate that hippocampal dysfunctions are involved in learning and memory deficits, dementia, Alzheimer's disease, epilepsy and mood disorders such as anxiety, depression and post-traumatic syndrome disorder, whereas the hippocampus participates also in the therapeutic mechanisms of numerous medicines. Not surprisingly, several drugs acting via 5-HT mechanisms are efficacious to some extent in some diseases and the link between 5-HT and the hippocampus although clear remains difficult to untangle. For this reason, we review reported data concerning the distribution and the functional roles of the 5-HT receptors in the hippocampal region in health and disease. The impact of the 5-HT systems on the hippocampal function is such that the research of new 5-HT mechanisms and drugs is still very active. It concerns notably drugs acting at the 5-HT1A,2A,2C,4,6 receptor subtypes, in addition to the already existing drugs including the selective serotonin reuptake inhibitors.
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Affiliation(s)
- Cristiano Bombardi
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy.
| | - Annamaria Grandis
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Nela Pivac
- Division of Molecular Medicine, Rudier Boskovic Institute, Zagreb, Croatia
| | - Marina Sagud
- Clinical Hospital Center Zagreb and School of Medicine University of Zagreb, Zagreb, Croatia
| | - Guillaume Lucas
- Neurocentre Magendie, INSERM 1215, Université de Bordeaux, Bordeaux, France
| | - Abdeslam Chagraoui
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Normandie University, UNIROUEN, INSERM U1239, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Valérie Lemaire-Mayo
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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Petrucci AN, Joyal KG, Purnell BS, Buchanan GF. Serotonin and sudden unexpected death in epilepsy. Exp Neurol 2019; 325:113145. [PMID: 31866464 DOI: 10.1016/j.expneurol.2019.113145] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/12/2019] [Accepted: 12/10/2019] [Indexed: 12/20/2022]
Abstract
Epilepsy is a highly prevalent disease characterized by recurrent, spontaneous seizures. Approximately one-third of epilepsy patients will not achieve seizure freedom with medical management and become refractory to conventional treatments. These patients are at greatest risk for sudden unexpected death in epilepsy (SUDEP). The exact etiology of SUDEP is unknown, but a combination of respiratory, cardiac, neuronal electrographic dysfunction, and arousal impairment is thought to underlie SUDEP. Serotonin (5-HT) is involved in regulation of breathing, sleep/wake states, arousal, and seizure modulation and has been implicated in the pathophysiology of SUDEP. This review explores the current state of understanding of the relationship between 5-HT, epilepsy, and respiratory and autonomic control processes relevant to SUDEP in epilepsy patients and in animal models.
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Affiliation(s)
- Alexandra N Petrucci
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America
| | - Katelyn G Joyal
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America
| | - Benton S Purnell
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America
| | - Gordon F Buchanan
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States of America; Department of Neurology, University of Iowa, Iowa City, IA 52242, United States of America; Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States of America.
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7
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Pottoo FH, Javed MN, Barkat MA, Alam MS, Nowshehri JA, Alshayban DM, Ansari MA. Estrogen and Serotonin: Complexity of Interactions and Implications for Epileptic Seizures and Epileptogenesis. Curr Neuropharmacol 2019; 17:214-231. [PMID: 29956631 PMCID: PMC6425080 DOI: 10.2174/1570159x16666180628164432] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 02/01/2018] [Accepted: 06/25/2018] [Indexed: 12/15/2022] Open
Abstract
A burgeoning literature documents the confluence of ovarian steroids and central serotonergic systems in the in-junction of epileptic seizures and epileptogenesis. Estrogen administration in animals reduces neuronal death from seizures by up-regulation of the prosurvival molecule i.e. Bcl-2, anti-oxidant potential and protection of NPY interneurons. Serotonin modulates epileptiform activity in either direction i.e administration of 5-HT agonists or reuptake inhibitors leads to the acti-vation of 5-HT3 and 5-HT1A receptors tending to impede focal and generalized seizures, while depletion of brain 5-HT along with the destruction of serotonergic terminals leads to expanded neuronal excitability hence abatement of seizure threshold in experimental animal models. Serotonergic neurotransmission is influenced by the organizational activity of ster-oid hormones in the growing brain and the actuation effects of steroids which come in adulthood. It is further established that ovarian steroids bring induction of dendritic spine proliferation on serotonin neurons thus thawing a profound effect on sero-tonergic transmission. This review features 5-HT1A and 5-HT3 receptors as potential targets for ameliorating seizure-induced neurodegeneration and recurrent hypersynchronous neuronal activity. Indeed 5-HT3 receptors mediate cross-talk be-tween estrogenic and serotonergic pathways, and could be well exploited for combinatorial drug therapy against epileptogen-esis.
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Affiliation(s)
- Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University (Formerly University of Dammam), Dammam 31441, Saudi Arabia
| | - Md Noushad Javed
- Department of Pharmaceutics, School of Pharmaceutical Education and Research, Jamia Hamdard, New-Delhi, India
| | - Md Abul Barkat
- Department of Pharmacy, School of Medical and Allied Sciences, K.R.Mangalam University, Gurgaon, India
| | - Md Sabir Alam
- Department of Pharmacy, School of Medical and Allied Sciences, K.R.Mangalam University, Gurgaon, India
| | - Javaid Ashraf Nowshehri
- Department of Pharmaceutical Sciences, Faculty of Applied Sc. and Tech., University of Kashmir, Srinagar, India
| | - Dhafer Mahdi Alshayban
- Department of Clinical Pharmacy, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University (Formerly University of Dammam), Dammam 31441, Saudi Arabia
| | - Mohammad Azam Ansari
- Department of Epidemic Disease Research, Institute for Research and Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
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Zestos AG, Luna-Munguia H, Stacey WC, Kennedy RT. Use and Future Prospects of in Vivo Microdialysis for Epilepsy Studies. ACS Chem Neurosci 2019; 10:1875-1883. [PMID: 30001105 DOI: 10.1021/acschemneuro.8b00271] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Epilepsy is a common neurological disease characterized by recurrent unpredictable seizures. For the last 30 years, microdialysis sampling has been used to measure changes in excitatory and inhibitory neurotransmitter concentrations before, during, and after seizures. These advances have fostered breakthroughs in epilepsy research by identifying neurochemical changes associated with seizures and correlating them to electrophysiological data. Recent advances in methodology may be useful in further delineating the chemical underpinnings of seizures. A new model of ictogenesis has been developed that allows greater control over the timing of seizures that are similar to spontaneous seizures. This model will facilitate making chemical measurements before and during a seizure. Recent advancements in microdialysis sampling, including the use of segmented flow, "fast" liquid chromatography (LC), and capillary electrophoresis with laser-induced fluorescence (CE-LIF) have significantly improved temporal resolution to better than 1 min, which could be used to measure transient, spontaneous neurochemical changes associated with seizures. Microfabricated sampling probes that are markedly smaller than conventional probes and allow for a much greater spatial resolution have been developed. They may allow the targeting of specific brain regions important to epilepsy studies. Coupling microdialysis sampling to optogenetics and light-stimulated release of neurotransmitters may also prove useful for studying epileptic seizures.
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Affiliation(s)
- Alexander G. Zestos
- Department of Chemistry, Center for Behavioral Neuroscience, American University, Washington, D.C. 20016, United States
| | - Hiram Luna-Munguia
- Departamento de Neurobiologia Conductual y Cognitiva, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Campus UNAM-Juriquilla, Queretaro 76230, Mexico
| | - William C. Stacey
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
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9
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Gharib A, Komaki A, Manoochehri Khoshinani H, Saidijam M, Barkley V, Sarihi A, Mirnajafi-Zadeh J. Intrahippocampal 5-HT 1A receptor antagonist inhibits the improving effect of low-frequency stimulation on memory impairment in kindled rats. Brain Res Bull 2019; 148:109-117. [PMID: 30902574 DOI: 10.1016/j.brainresbull.2019.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 02/22/2019] [Accepted: 03/14/2019] [Indexed: 01/10/2023]
Abstract
In addition to its anticonvulsant effect, low frequency stimulation (LFS) improves learning and memory in kindled animals. In the present study, the role of 5-HT1A receptors in mediating LFS' improving effect on spatial learning and memory was investigated in amygdala-kindled rats. Amygdala kindling was conducted in a semi-rapid kindling stimulations (12 stimulations per day) in male Wistar rats. LFS (4 trains of 0.1 ms pulse duration at 1 Hz, 200 pulses, 50-150 μA, at 5 min intervals) was applied after termination of kindling stimulations. NAD-299 (a selective 5-HT1A receptor antagonist; 2.5 and 5 μg/μl) was microinjected into the hippocampal CA1 before applying LFS. The Morris water maze, and novel object recognition tests were conducted after the last kindling stimulation. Hippocampal samples were also prepared, and 5-HT1A receptor gene expression levels were assessed using quantitative RT-PCR. In kindled animals, LFS reduced impairments in spatial learning and memory in the Morris water maze and novel object recognition tests. Microinjection of NAD doses of 5 μg/μl reduced the effects of LFS on learning and memory. The gene expression level of 5-HT1A receptors increased significantly in the hippocampus of amygdala-kindled rats. However, LFS applied after kindling stimulations inhibited this effect. It seems that activation of 5-HT1A receptors in the CA1 field is necessary for LFS' improving effects on spatial learning and memory in kindled animals; although surprisingly, LFS application prevented the elevation in gene expression of 5-HT1A receptors in kindled animals.
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Affiliation(s)
- Alireza Gharib
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Hamed Manoochehri Khoshinani
- Department of Molecular Medicine and Genetics, School of Medicine, Hamedan University of Medical Sciences, Hamadan, Iran
| | - Massoud Saidijam
- Department of Molecular Medicine and Genetics, School of Medicine, Hamedan University of Medical Sciences, Hamadan, Iran
| | - Victoria Barkley
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Abdolrahman Sarihi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran, Iran.
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10
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Clinical and electroencephalographic correlates of psychiatric features in children with frontal lobe epilepsy. Epilepsy Behav 2019; 92:283-289. [PMID: 30731294 DOI: 10.1016/j.yebeh.2019.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/04/2019] [Accepted: 01/04/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND OBJECTIVE Frontal lobe epilepsy (FLE) is often associated with psychiatric features, although the factors predisposing to the concurrence of these conditions have yet to be determined, especially in younger children. We aimed at defining possible clinical and electroencephalography (EEG) features that may enhance the psychiatric risk in pediatric FLE. METHOD We performed a structured psychiatric assessment of 59 children with FLE, using both categorical and dimensional approaches, correlated psychopathology with epilepsy data, and cognitive development. RESULTS About 1/3 of patients with FLE displayed intellectual disability (ID), and more than 2/3 displayed psychiatric disorders, including depression, disruptive behaviors, anxiety, and bipolar/psychotic disorders. Psychiatric dimensions such as impulse control problems, attentional deficits, social problems, and aggressive behaviors were frequent features of FLE. Intellectual disability was associated with an earlier onset of psychiatric disorders and more frequent disruptive behavior disorders and aggressiveness. Long-standing epilepsy and bilateral or anterior frontal EEG abnormalities also increased the risk of psychopathology. Finally, right-hemisphere lesions were associated with disruptive behavior disorders, fast EEG rhythms with attention/memory problems, and phases of seizure remission with impulse control problems. CONCLUSIONS Clinical and EEG markers of increased psychopathological risk may help in defining consistent at-risk subgroups within FLE and improving early diagnosis, prognosis, and treatment. Categorical and dimensional approaches to psychiatric diagnosis may generate new research hypotheses and support the investigation of the complex pathophysiological bases shared by different neurodevelopmental disturbances.
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Lin X, Duan X, Jacobs C, Ullmann J, Chan CY, Chen S, Cheng SH, Zhao WN, Poduri A, Wang X, Haggarty SJ, Shi P. High-throughput brain activity mapping and machine learning as a foundation for systems neuropharmacology. Nat Commun 2018; 9:5142. [PMID: 30510233 PMCID: PMC6277389 DOI: 10.1038/s41467-018-07289-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/23/2018] [Indexed: 12/19/2022] Open
Abstract
Technologies for mapping the spatial and temporal patterns of neural activity have advanced our understanding of brain function in both health and disease. An important application of these technologies is the discovery of next-generation neurotherapeutics for neurological and psychiatric disorders. Here, we describe an in vivo drug screening strategy that combines high-throughput technology to generate large-scale brain activity maps (BAMs) with machine learning for predictive analysis. This platform enables evaluation of compounds’ mechanisms of action and potential therapeutic uses based on information-rich BAMs derived from drug-treated zebrafish larvae. From a screen of clinically used drugs, we found intrinsically coherent drug clusters that are associated with known therapeutic categories. Using BAM-based clusters as a functional classifier, we identify anti-seizure-like drug leads from non-clinical compounds and validate their therapeutic effects in the pentylenetetrazole zebrafish seizure model. Collectively, this study provides a framework to advance the field of systems neuropharmacology. A major goal in neuropharmacology is to develop new tools to effectively test the therapeutic potential of pharmacological agents to treat neurological and psychiatric conditions. Here, authors present an in vivo drug screening system that generates large-scale brain activity maps to be used with machine learning to predict the therapeutic potential of clinically relevant drug leads.
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Affiliation(s)
- Xudong Lin
- Department of Biomedical Engineering, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China
| | - Xin Duan
- Department of Biomedical Science, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China
| | - Claire Jacobs
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Department of Neurology, Harvard Medical School, Boston, MA, 02114, USA
| | - Jeremy Ullmann
- Epilepsy Genetics Program and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA
| | - Chung-Yuen Chan
- Department of Biomedical Engineering, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China
| | - Siya Chen
- Department of Biomedical Engineering, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China
| | - Shuk-Han Cheng
- Department of Biomedical Science, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China
| | - Wen-Ning Zhao
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Department of Neurology, Harvard Medical School, Boston, MA, 02114, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program and F.M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA
| | - Xin Wang
- Department of Biomedical Science, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China. .,Shenzhen Research Institute, City University of Hong Kong, 518057, Shenzhen, China.
| | - Stephen J Haggarty
- Chemical Neurobiology Laboratory, Center for Genomic Medicine, Massachusetts General Hospital, Department of Neurology, Harvard Medical School, Boston, MA, 02114, USA.
| | - Peng Shi
- Department of Biomedical Engineering, City University of Hong Kong, 999077, Kowloon, Hong Kong SAR, China. .,Shenzhen Research Institute, City University of Hong Kong, 518057, Shenzhen, China.
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12
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Navidhamidi M, Ghasemi M, Mehranfard N. Epilepsy-associated alterations in hippocampal excitability. Rev Neurosci 2018; 28:307-334. [PMID: 28099137 DOI: 10.1515/revneuro-2016-0059] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/03/2016] [Indexed: 11/15/2022]
Abstract
The hippocampus exhibits a wide range of epilepsy-related abnormalities and is situated in the mesial temporal lobe, where limbic seizures begin. These abnormalities could affect membrane excitability and lead to overstimulation of neurons. Multiple overlapping processes refer to neural homeostatic responses develop in neurons that work together to restore neuronal firing rates to control levels. Nevertheless, homeostatic mechanisms are unable to restore normal neuronal excitability, and the epileptic hippocampus becomes hyperexcitable or hypoexcitable. Studies show that there is hyperexcitability even before starting recurrent spontaneous seizures, suggesting although hippocampal hyperexcitability may contribute to epileptogenesis, it alone is insufficient to produce epileptic seizures. This supports the concept that the hippocampus is not the only substrate for limbic seizure onset, and a broader hyperexcitable limbic structure may contribute to temporal lobe epilepsy (TLE) seizures. Nevertheless, seizures also occur in conditions where the hippocampus shows a hypoexcitable phenotype. Since TLE seizures most often originate in the hippocampus, it could therefore be assumed that both hippocampal hypoexcitability and hyperexcitability are undesirable states that make the epileptic hippocampal network less stable and may, under certain conditions, trigger seizures.
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13
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Werner FM, Coveñas R. Classical neurotransmitters and neuropeptides involved in generalized epilepsy in a multi-neurotransmitter system: How to improve the antiepileptic effect? Epilepsy Behav 2017; 71:124-129. [PMID: 25819950 DOI: 10.1016/j.yebeh.2015.01.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 12/20/2022]
Abstract
Here, we describe in generalized epilepsies the alterations of classical neurotransmitters and neuropeptides acting at specific subreceptors. In order to consider a network context rather than one based on focal substrates and in order to make the interaction between neurotransmitters and neuropeptides and their specific subreceptors comprehensible, neural networks in the hippocampus, thalamus, and cerebral cortex are described. In this disease, a neurotransmitter imbalance between dopaminergic and serotonergic neurons and between presynaptic GABAergic neurons (hypoactivity) and glutaminergic neurons (hyperactivity) occurs. Consequently, combined GABAA agonists and NMDA antagonists could furthermore stabilize the neural networks in a multimodal pharmacotherapy. The antiepileptic effect and the mechanisms of action of conventional and recently developed antiepileptic drugs are reviewed. The GASH:Sal animal model can contribute to examine the efficacy of antiepileptic drugs. The issues of whether the interaction of classical neurotransmitters with other subreceptors (5-HT7, metabotropic 5 glutaminergic, A2A adenosine, and alpha nicotinic 7 cholinergic receptors) or whether the administration of agonists/antagonists of neuropeptides might improve the therapeutic effect of antiepileptic drugs should be addressed. 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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Affiliation(s)
- Felix-Martin Werner
- Höhere Berufsfachschule für Altenpflege und Ergotherapie der Euro Akademie Pößneck, Pößneck, Germany; Institute of Neurosciences of Castilla y León (INCYL), Laboratory of Neuroanatomy of the Peptidergic Systems (Lab. 14), University of Salamanca, Salamanca, Spain.
| | - Rafael Coveñas
- Institute of Neurosciences of Castilla y León (INCYL), Laboratory of Neuroanatomy of the Peptidergic Systems (Lab. 14), University of Salamanca, Salamanca, Spain.
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14
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The effect of sertraline and 8-OH-DPAT on the PTZ_induced seizure threshold: Role of the nitrergic system. Seizure 2017; 45:119-124. [DOI: 10.1016/j.seizure.2016.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 11/22/2022] Open
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15
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Serotonin receptor antagonists increase fast ripple activity in rats treated with kainic acid. Brain Res Bull 2016; 121:59-67. [DOI: 10.1016/j.brainresbull.2016.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/30/2015] [Accepted: 01/04/2016] [Indexed: 11/22/2022]
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16
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The role of different serotonin receptor subtypes in seizure susceptibility. Exp Brain Res 2013; 232:347-67. [PMID: 24232860 DOI: 10.1007/s00221-013-3757-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 10/27/2013] [Indexed: 10/26/2022]
Abstract
5-Hydroxytryptamine (5-HT) has the most diverse set of receptors in comparison with any other neurotransmitter or hormone in the body. To date, seven families of 5-HT receptors have been characterized. A great number of studies have been published regarding the role of 5-HT and its receptors in seizures. However, with a few exceptions, the net effect of activating or inhibiting each 5-HT receptor subtype on the development or severity of seizures remains controversial. Additionally, the results of studies, which have used knockout animals to investigate the role of 5-HT receptors in seizures, have sometimes been contradictory to those which have used pharmacological tools. The present study aims to review the available data regarding the influence of each receptor subtype on seizure development and, when possible, reconcile between the apparently different results obtained in these studies.
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17
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Cardamone L, Salzberg MR, O'Brien TJ, Jones NC. Antidepressant therapy in epilepsy: can treating the comorbidities affect the underlying disorder? Br J Pharmacol 2013; 168:1531-54. [PMID: 23146067 PMCID: PMC3605864 DOI: 10.1111/bph.12052] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 12/20/2022] Open
Abstract
There is a high incidence of psychiatric comorbidity in people with epilepsy (PWE), particularly depression. The manifold adverse consequences of comorbid depression have been more clearly mapped in recent years. Accordingly, considerable efforts have been made to improve detection and diagnosis, with the result that many PWE are treated with antidepressant drugs, medications with the potential to influence both epilepsy and depression. Exposure to older generations of antidepressants (notably tricyclic antidepressants and bupropion) can increase seizure frequency. However, a growing body of evidence suggests that newer ('second generation') antidepressants, such as selective serotonin reuptake inhibitors or serotonin-noradrenaline reuptake inhibitors, have markedly less effect on excitability and may lead to improvements in epilepsy severity. Although a great deal is known about how antidepressants affect excitability on short time scales in experimental models, little is known about the effects of chronic antidepressant exposure on the underlying processes subsumed under the term 'epileptogenesis': the progressive neurobiological processes by which the non-epileptic brain changes so that it generates spontaneous, recurrent seizures. This paper reviews the literature concerning the influences of antidepressants in PWE and in animal models. The second section describes neurobiological mechanisms implicated in both antidepressant actions and in epileptogenesis, highlighting potential substrates that may mediate any effects of antidepressants on the development and progression of epilepsy. Although much indirect evidence suggests the overall clinical effects of antidepressants on epilepsy itself are beneficial, there are reasons for caution and the need for further research, discussed in the concluding section.
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Affiliation(s)
- L Cardamone
- Department of Medicine (RMH), University of Melbourne, Melbourne, Victoria, Australia
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18
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19
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The antidepressant drug fluoxetine inhibits persistent sodium currents and seizure-like events. Epilepsy Res 2012; 101:174-81. [DOI: 10.1016/j.eplepsyres.2012.03.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 03/12/2012] [Accepted: 03/28/2012] [Indexed: 11/23/2022]
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20
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5-HT(3) receptor mediates the dose-dependent effects of citalopram on pentylenetetrazole-induced clonic seizure in mice: involvement of nitric oxide. Epilepsy Res 2012; 101:217-27. [PMID: 22578701 DOI: 10.1016/j.eplepsyres.2012.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 03/21/2012] [Accepted: 04/07/2012] [Indexed: 01/05/2023]
Abstract
Citalopram is a selective serotonin reuptake inhibitor (SSRI), widely used in the treatment of depressive disorders. It has been shown that citalopram affects seizure susceptibility. Although the exact mechanism of these effects are not yet fully understood, recent data suggest that 5HT(3) receptors and nitric oxide (NO) might participate in the central effects of SSRIs. In this study in a mouse model of clonic seizure induced by pentylenetetrazole we investigated whether 5-HT(3) receptors are involved in the effects of citalopram on seizure threshold. In our experiments, citalopram at lower doses (0.5 and 1mg/kg, i.p) significantly increased the seizure threshold and at higher doses (≥25mg/kg) showed proconvulsive effects. Moreover, mCPBG (a 5-HT(3) receptor agonist) at low and non-effective doses augmented while non-effective doses of tropisetron prevented the anticonvulsive properties of citalopram. On the other hand, Low doses of nitric oxide synthase inhibitors l-NAME and 7-NI alone or in combination with lower doses of 5-HT(3) receptor agonist enhanced the anticonvulsive property of citalopram, while l-arginine (NO precursor) alone or in combination with tropisetron blocked the protective effect of citalopram. In summary, our findings demonstrate that 5-HT(3) receptor mediates the anticonvulsant properties of low doses of citalopram, whereas it seems that the proconvulsive effect is mostly mediated through the NO pathway and can be totally blocked by NOS inhibitors. This could propose a new approach toward finding the mechanism of citalopram activity, curtailing the adverse effects of citalopram and perhaps managing the convulsions as a vicious consequence of citalopram overdose.
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Hansen SL, Sterjev Z, Werngreen M, Simonsen BJ, Knudsen KE, Nielsen AH, Pedersen ME, Badolo L, Kristiansen U, Vestergaard HT. Does brain slices from pentylenetetrazole-kindled mice provide a more predictive screening model for antiepileptic drugs? Eur J Pharmacol 2012; 682:43-9. [DOI: 10.1016/j.ejphar.2012.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 01/17/2012] [Accepted: 01/28/2012] [Indexed: 12/01/2022]
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Vermoesen K, Massie A, Smolders I, Clinckers R. The antidepressants citalopram and reboxetine reduce seizure frequency in rats with chronic epilepsy. Epilepsia 2012; 53:870-8. [PMID: 22429158 DOI: 10.1111/j.1528-1167.2012.03436.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE For a long time, antidepressants have been thought to possess proconvulsant properties. This assumption, however, remains controversial, since anticonvulsant effects have been attributed to certain antidepressants. To date, it remains unclear which antidepressants can be used for the treatment of depression in patients with epilepsy. In this respect, studies investigating the convulsant liability of antidepressants in a chronic epilepsy model can give valuable information. The present study was designed to determine the seizure liability of citalopram and reboxetine in the kainic acid-induced post-status epilepticus model for temporal lobe epilepsy. METHODS Two months after the induction of status epilepticus, chronic epileptic rats (n = 16) were video-electroencephalography (EEG) monitored during seven consecutive weeks. Weeks 1, 3, 5, and 7 served as sham weeks during which the rats received intraperitoneal saline injections for four consecutive days, followed by a 3-day sham washout period during which no injections were given. During weeks 2, 4, and 6, rats received intraperitoneal injections with either citalopram (5, 10, and 15 mg/kg, once daily, n = 8) or reboxetine (10, 20, and 30 mg/kg, twice daily, n = 8) for 4 days, again followed by a washout period of 3 days. Drugs were administered in a randomly assigned fixed-dose regimen per week. Each rat served as its own control. The drug doses were selected based on the doses reported to have antidepressant effects in rats. KEY FINDINGS Citalopram significantly decreased the spontaneous seizure frequency at the highest dose tested, that is, the mean number of seizures decreased from 12.8 seizures to 8.8 seizures per week (31%) after treatment with 15 mg/kg citalopram. This dose also significantly decreased the cumulative seizure duration. Administration of 5 and 10 mg/kg citalopram did not alter the seizure frequency. The two highest doses of reboxetine significantly decreased the spontaneous seizure frequency, that is, 20 mg/kg reboxetine decreased the seizure frequency from 14.1 to 7.9 (44%) and 30 mg/kg reboxetine decreased the seizure frequency from 11.8 to 7.2 (39%). In addition, both doses significantly decreased the cumulative seizure duration. Administration of 10 mg/kg reboxetine did not alter seizure frequency. Citalopram and reboxetine had no effect on seizure severity and seizure duration in any of the doses tested. SIGNIFICANCE In general we can conclude that antidepressant doses of citalopram and reboxetine have, depending on the dose, an anticonvulsant effect or no effect on spontaneous seizures in the kainic acid-induced post-status epilepticus rat model.
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Affiliation(s)
- Katia Vermoesen
- Center for Neurosciences, Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
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23
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Igelström KM. Preclinical antiepileptic actions of selective serotonin reuptake inhibitors--implications for clinical trial design. Epilepsia 2012; 53:596-605. [PMID: 22416943 DOI: 10.1111/j.1528-1167.2012.03427.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) can reduce seizure frequency in humans, but no large-scale clinical trials have been done to test the utility of SSRIs as potential antiepileptic drugs. This may be caused in part by a small number of reports on seizures triggered by SSRI treatment. The preclinical literature on SSRIs is somewhat conflicting, which is likely to contribute to the hesitance in accepting SSRIs as possible anticonvulsant drug therapy. A careful review of preclinical studies reveals that SSRIs appear to have region-specific and seizure subtype-specific effects, with models of chronic partial epilepsy being more likely to respond than models of acute generalized seizures. Moreover, this preclinical profile is similar to that of clinical antiepileptic drugs. These observations suggest that SSRIs are promising antiepileptic agents, and that clinical trials may benefit from defining patient groups according to the underlying pathology.
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Affiliation(s)
- Kajsa M Igelström
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
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24
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Vermoesen K, Serruys ASK, Loyens E, Afrikanova T, Massie A, Schallier A, Michotte Y, Crawford AD, Esguerra CV, de Witte PAM, Smolders I, Clinckers R. Assessment of the convulsant liability of antidepressants using zebrafish and mouse seizure models. Epilepsy Behav 2011; 22:450-60. [PMID: 21962757 DOI: 10.1016/j.yebeh.2011.08.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/18/2011] [Accepted: 08/19/2011] [Indexed: 11/25/2022]
Abstract
In the past, antidepressants have been thought to possess proconvulsant properties. This assumption remains controversial, however, because anticonvulsant effects have been attributed to certain antidepressants. To date, it remains unclear which antidepressants can be used for the treatment of patients with epilepsy with depression. The present study was designed to determine the anticonvulsant and/or proconvulsant effects of three antidepressants (citalopram, reboxetine, bupropion) against pilocarpine- and pentylenetetrazole-induced acute seizures in larval zebrafish and mice. In zebrafish, all antidepressants were anticonvulsant in the pentylenetetrazole model. In addition, citalopram was anticonvulsant in the zebrafish pilocarpine model, whereas reboxetine and bupropion were without significant effect. In mice all three antidepressants increased some thresholds for pentylenetetrazole-induced convulsive-like behaviors at varying doses, whereas thresholds for pilocarpine-induced convulsive-like behaviors were generally lowered, particularly at the highest doses tested. In general we conclude that the convulsant liability of antidepressants is model and concentration dependent.
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Affiliation(s)
- Katia Vermoesen
- Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neuroscience, Vrije Universiteit Brussel, Brussels, Belgium
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25
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Bahremand A, Payandemehr B, Rahimian R, Ziai P, Pourmand N, Loloee S, Ebrahimi A, Ghasemi A, Fakhfouri G, Ghasemi M, Dehpour AR. The role of 5-HT(3) receptors in the additive anticonvulsant effects of citalopram and morphine on pentylenetetrazole-induced clonic seizures in mice. Epilepsy Behav 2011; 21:122-7. [PMID: 21531632 DOI: 10.1016/j.yebeh.2011.03.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 03/07/2011] [Accepted: 03/08/2011] [Indexed: 11/28/2022]
Abstract
Citalopram, a selective serotonin reuptake inhibitor (SSRI), is frequently used in the treatment of major depressive disorders. In addition to its antidepressant features, citalopram shows some anticonvulsive properties at lower doses, whereas higher doses, ingested in cases of suicide, have been associated with seizures. Moreover, some reports support the enhancing effect of morphine on different responses of SSRIs such as analgesic and anticonvulsant properties. Although the exact mechanisms of these additive effects are not yet fully understood, 5-HT(3) receptor has recently been shown to play an important role in the central effects of SSRIs and morphine. In this regard, we used a model of clonic seizures induced by pentylenetetrazole (PTZ) in male NMRI mice to investigate whether morphine and citalopram exhibit additive anticonvulsant effects and, if so, whether this effect is mediated through modulation of 5-HT(3) receptors. In our study, citalopram at lower doses (0.5 and 1 mg/kg, ip) significantly increased the seizure threshold (P<0.01) and at a higher dose (50 mg/kg) had proconvulsive effects. Moreover, morphine at low and noneffective doses had additive effects on the anticonvulsive properties of citalopram. This additive effect was prevented by pretreatment with low and noneffective doses of tropisetron (a 5-HT(3) receptor antagonist) and augmented by 1-(m-chlorophenyl)-biguanide (mCPBG, a 5-HT(3) receptor agonist). Moreover, low doses of morphine (0.1 and 0.5 mg/kg) alone or in combination with potent doses of 5-HT(3) receptor agonist or antagonist could not alter the proconvulsive properties of citalopram at higher dose (50 mg/kg), ruling out the contribution of 5-HT(3) to this effect. In summary, our findings demonstrate that 5-HT(3) receptor mediates the additive anticonvulsant properties of morphine and low-dose citalopram. This could constitute a new approach to augmenting the efficacy and curtailing the adverse effects of citalopram.
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Affiliation(s)
- Arash Bahremand
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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26
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Clinckers R, Zgavc T, Vermoesen K, Meurs A, Michotte Y, Smolders I. Pharmacological and neurochemical characterization of the involvement of hippocampal adrenoreceptor subtypes in the modulation of acute limbic seizures. J Neurochem 2010; 115:1595-607. [DOI: 10.1111/j.1471-4159.2010.07065.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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27
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Central serotonin 1A receptor binding in temporal lobe epilepsy: a [carbonyl-(11)C]WAY-100635 PET study. Epilepsy Behav 2010; 19:467-73. [PMID: 20850389 DOI: 10.1016/j.yebeh.2010.07.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 07/16/2010] [Accepted: 07/28/2010] [Indexed: 01/03/2023]
Abstract
We performed positron emission tomography using [carbonyl-(11)C]WAY-100635, a serotonin 1A (5-HT(1A)) receptor antagonist, in 13 patients with temporal lobe epilepsy (TLE) and in 13 controls. 5-HT(1A) receptor distribution mapping allowed correct lateralization of the epileptogenic temporal lobe in all patients. 5-HT(1A) receptor binding potential (BP(ND)) was significantly reduced in almost all temporal regions of the epileptogenic lobe. Compared with controls, the patients had significantly decreased BP(ND) values in the hippocampus, parahippocampal gyrus, and amygdala. The asymmetry index (AI), which characterizes the interhemispheric asymmetry in BP(ND), was significantly higher in patients than in controls in most regions. Depression scores were not significantly correlated with BP(ND) or AI values. Our data provide further evidence of functional changes in the serotonergic system in TLE. Molecular imaging of the 5-HT(1A) receptor may help to define the in vivo neurochemistry of TLE, and may provide a valuable tool in the noninvasive presurgical assessment of patients with medically refractory TLE.
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28
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Van Gompel JJ, Chang SY, Goerss SJ, Kim IY, Kimble C, Bennet KE, Lee KH. Development of intraoperative electrochemical detection: wireless instantaneous neurochemical concentration sensor for deep brain stimulation feedback. Neurosurg Focus 2010; 29:E6. [PMID: 20672923 PMCID: PMC2939376 DOI: 10.3171/2010.5.focus10110] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Deep brain stimulation (DBS) is effective when there appears to be a distortion in the complex neurochemical circuitry of the brain. Currently, the mechanism of DBS is incompletely understood; however, it has been hypothesized that DBS evokes release of neurochemicals. Well-established chemical detection systems such as microdialysis and mass spectrometry are impractical if one is assessing changes that are happening on a second-to-second time scale or for chronically used implanted recordings, as would be required for DBS feedback. Electrochemical detection techniques such as fast-scan cyclic voltammetry (FSCV) and amperometry have until recently remained in the realm of basic science; however, it is enticing to apply these powerful recording technologies to clinical and translational applications. The Wireless Instantaneous Neurochemical Concentration Sensor (WINCS) currently is a research device designed for human use capable of in vivo FSCV and amperometry, sampling at subsecond time resolution. In this paper, the authors review recent advances in this electrochemical application to DBS technologies. The WINCS can detect dopamine, adenosine, and serotonin by FSCV. For example, FSCV is capable of detecting dopamine in the caudate evoked by stimulation of the subthalamic nucleus/substantia nigra in pig and rat models of DBS. It is further capable of detecting dopamine by amperometry and, when used with enzyme linked sensors, both glutamate and adenosine. In conclusion, WINCS is a highly versatile instrument that allows near real-time (millisecond) detection of neurochemicals important to DBS research. In the future, the neurochemical changes detected using WINCS may be important as surrogate markers for proper DBS placement as well as the sensor component for a "smart" DBS system with electrochemical feedback that allows automatic modulation of stimulation parameters. Current work is under way to establish WINCS use in humans.
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Affiliation(s)
| | - Su-Youne Chang
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota
| | - Stephan J. Goerss
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota
| | - In Yong Kim
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota
| | | | | | - Kendall H. Lee
- Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota
- Division of Engineering, Mayo Clinic, Rochester, Minnesota
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Ohno Y, Sofue N, Imaoku T, Morishita E, Kumafuji K, Sasa M, Serikawa T. Serotonergic Modulation of Absence-Like Seizures in Groggy Rats: a Novel Rat Model of Absence Epilepsy. J Pharmacol Sci 2010; 114:99-105. [DOI: 10.1254/jphs.10156fp] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Jaako K, Zharkovsky T, Zharkovsky A. Effects of repeated citalopram treatment on kainic acid-induced neurogenesis in adult mouse hippocampus. Brain Res 2009; 1288:18-28. [DOI: 10.1016/j.brainres.2009.06.089] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 06/23/2009] [Accepted: 06/26/2009] [Indexed: 02/01/2023]
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Direct enhancement of hippocampal dopamine or serotonin levels as a pharmacodynamic measure of combined antidepressant-anticonvulsant action. Neuropharmacology 2008; 54:1017-28. [PMID: 18378264 DOI: 10.1016/j.neuropharm.2008.02.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 02/08/2008] [Accepted: 02/11/2008] [Indexed: 11/22/2022]
Abstract
The neurobiological relationships between epilepsy and depression are receiving increased experimental attention. A key role for limbic monoamines in depression has been established and we recently showed the importance of hippocampal monoamines in limbic seizure control. We here studied whether anticonvulsant compounds are antidepressant and can elevate hippocampal dopamine (DA) or serotonin (5-HT) levels determined by in vivo microdialysis in rats. We used assessment of seizure severity in the focal pilocarpine model, antidepressant-like activity within the rat forced swim and the mouse tail suspension tests, and locomotor activity in an open field as behavioural tests. We studied the tricyclic antidepressant imipramine, the selective 5-HT reuptake inhibitor citalopram and the selective DA reuptake blocker GBR-12909. These compounds with combined antidepressant-anticonvulsant properties all directly enhanced extracellular hippocampal DA or 5-HT levels. Since glutamate-mediated hyperexcitability in temporal lobe regions seems to be involved in disturbed emotional behaviour, we next investigated possible antidepressant effects and hippocampal DA or 5-HT modulations exerted by selective ionotropic and metabotropic glutamate receptor ligands with anticonvulsant properties. Combined anticonvulsant-antidepressant activities of the NMDA antagonist MK-801 and the mGluR group I antagonists (AIDA, MPEP) were also associated with locally elicited increases in hippocampal DA and/or 5-HT levels. This study highlights that the hippocampus is an important site of action of combined anticonvulsant-antidepressant and monoamine enhancing effects.
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Meurs A, Clinckers R, Ebinger G, Michotte Y, Smolders I. Seizure activity and changes in hippocampal extracellular glutamate, GABA, dopamine and serotonin. Epilepsy Res 2007; 78:50-9. [PMID: 18054462 DOI: 10.1016/j.eplepsyres.2007.10.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 10/08/2007] [Accepted: 10/18/2007] [Indexed: 12/28/2022]
Abstract
Increases in hippocampal extracellular neurotransmitter levels have consistently been observed during temporal lobe seizures in humans, but animal studies on this subject have yielded conflicting results. Our aim was to better characterise the relationship between seizure activity and changes in hippocampal glutamate, GABA, dopamine and serotonin by comparing three limbic seizure models which differ only in the pharmacological mechanism used to induce seizures. Seizures were evoked in freely moving rats by intrahippocampal microperfusion, via a microdialysis probe, of the muscarinic receptor agonist pilocarpine (10mM), GABA(A) receptor antagonist picrotoxin (100microM) or group I metabotropic glutamate receptor agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) (1mM). Seizure-related behavioural changes were scored and hippocampal extracellular glutamate, GABA, dopamine and serotonin concentrations were monitored. Seizures were of comparable severity in all groups. During seizures, hippocampal glutamate, GABA and dopamine concentrations increased in all groups. Glutamate increases were significantly higher in the picrotoxin group. Hippocampal serotonin concentration increased following pilocarpine and picrotoxin, but not DHPG. Our results suggest a direct relationship between seizure activity and increased hippocampal extracellular concentrations of glutamate, GABA and dopamine, but not serotonin. The fact that picrotoxin induces seizures by disinhibition, rather than direct excitation, may account for the larger glutamate increases in this group.
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Meurs A, Clinckers R, Ebinger G, Michotte Y, Smolders I. Sigma 1 receptor-mediated increase in hippocampal extracellular dopamine contributes to the mechanism of the anticonvulsant action of neuropeptide Y. Eur J Neurosci 2007; 26:3079-92. [PMID: 18005069 DOI: 10.1111/j.1460-9568.2007.05911.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The potent anticonvulsant properties of neuropeptide Y (NPY) are generally attributed to a Y2 receptor-mediated inhibition of glutamatergic synaptic transmission. Independent studies have shown that NPY increases brain dopamine content, possibly via interaction with sigma 1 receptors. Recently, we showed that increased extracellular hippocampal dopamine attenuates pilocarpine-induced limbic seizures via activation of hippocampal D2 receptors. Our aim in this study was to elucidate the role of increased hippocampal dopamine in the mechanism of the anticonvulsant action of NPY and to investigate the involvement of Y2 and sigma 1 receptors in this process. Limbic seizures were evoked in freely moving rats by intrahippocampal administration of pilocarpine via a microdialysis probe. NPY was administered intracerebroventricularly, intrahippocampally via the microdialysis probe, or coadministered intrahippocampally with the D2 receptor antagonist remoxipride, the Y2 receptor antagonist BIIE0246 or the sigma 1 receptor antagonist BD1047. Changes in hippocampal extracellular dopamine were monitored, and behavioural changes indicative of seizure activity were scored. Intracerebroventricular (10 nmol/3 microL) and intrahippocampal (20-50 microm) NPY administration increased hippocampal dopamine and attenuated pilocarpine-induced seizures. Hippocampal D2 receptor blockade (4 microm remoxipride) reversed the anticonvulsant effect of NPY. Y2 receptor blockade (1 microm BIIE0246) reversed the anticonvulsant effect of NPY but did not prevent NPY-induced increases in hippocampal dopamine. Sigma 1 receptor blockade (10 microm BD1047) abolished NPY-induced increases in hippocampal dopamine and reversed the anticonvulsant effect of NPY. Our results indicate that NPY-induced increases in hippocampal dopamine are mediated via sigma 1 receptors and contribute to the anticonvulsant effect of NPY via increased activation of hippocampal D2 receptors. This novel mechanism of anticonvulsant action of NPY is separate from, and may be complementary to, the well established Y2 receptor-mediated inhibition of hippocampal excitability.
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Affiliation(s)
- Alfred Meurs
- Department of Neurology, U. Z. Brussel, Laarbeeklaan 101,1090 Brussels, Belgium
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Alper K, Schwartz KA, Kolts RL, Khan A. Seizure incidence in psychopharmacological clinical trials: an analysis of Food and Drug Administration (FDA) summary basis of approval reports. Biol Psychiatry 2007; 62:345-54. [PMID: 17223086 DOI: 10.1016/j.biopsych.2006.09.023] [Citation(s) in RCA: 287] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/08/2006] [Accepted: 09/25/2006] [Indexed: 12/20/2022]
Abstract
BACKGROUND Clinical trial data provide an approach to the investigation of the effects of psychopharmacological agents, and psychiatric disorders themselves, on seizure threshold. METHODS We accessed public domain data from Food and Drug Administration (FDA) Phase II and III clinical trials as Summary Basis of Approval (SBA) reports that noted seizure incidence in trials of psychotropic drugs approved in the United States between 1985 and 2004, involving a total of 75,873 patients. We compared seizure incidence among active drug and placebo groups in psychopharmacological clinical trials and the published rates of unprovoked seizures in the general population. RESULTS Increased seizure incidence was observed with antipsychotics that was accounted for by clozapine and olanzapine, and with drugs indicated for the treatment of OCD that was accounted for by clomipramine. Alprazolam, bupropion immediate release (IR) form, and quetiapine were also associated with higher seizure incidence. The incidence of seizures was significantly lower among patients assigned to antidepressants compared to placebo (standardized incidence ratio = .48; 95% CI, .36- .61). In patients assigned to placebo, seizure incidence was greater than the published incidence of unprovoked seizures in community nonpatient samples. CONCLUSIONS Proconvulsant effects are associated with a subgroup of psychotropic drugs. Second-generation antidepressants other than bupropion have an apparent anticonvulsant effect. Depression, psychotic disorders, and OCD are associated with reduced seizure threshold.
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Affiliation(s)
- Kenneth Alper
- Department of Psychiatry, Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY 10016, USA.
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Rocha L, Lorigados-Pedre L, Orozco-Suárez S, Morales-Chacón L, Alonso-Vanegas M, García-Maeso I, Villeda-Hernández J, Osorio-Rico L, Estupiñán B, Quintana C. Autoradiography reveals selective changes in serotonin binding in neocortex of patients with temporal lobe epilepsy. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:1208-18. [PMID: 17513030 DOI: 10.1016/j.pnpbp.2007.04.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 04/18/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
The main goal of the present study was to evaluate binding to serotonin in the neocortex surrounding the epileptic focus of patients with mesial temporal lobe epilepsy (MTLE). Binding to 5-HT, 5-HT(1A), 5-HT(4), 5-HT(7) receptors and serotonin transporter (5-HTT) in T1-T2 gyri of 15 patients with MTLE and their correlations with clinical data, neuronal count and volume were determined. Autopsy material acquired from subjects without epilepsy (n=6) was used as control. The neocortex from MTLE patients demonstrated decreased cell count in layers III-IV (21%). No significant changes were detected on the neuronal volume. Autoradiography experiments showed the following results: reduced 5-HT and 5-HT(1A) binding in layers I-II (24% and 92%, respectively); enhanced 5-HT(4) binding in layers V-VI (32%); no significant changes in 5-HT(7) binding; reduced 5-HTT binding in all layers (I-II, 90.3%; III-IV, 90.3%, V-VI, 86.9%). Significant correlations were found between binding to 5-HT(4) and 5-HT(7) receptors and age of seizure onset, duration of epilepsy and duration of antiepileptic treatment. The present results support an impaired serotoninergic transmission in the neocortex surrounding the epileptic focus of patients with MTLE, a situation that could be involved in the initiation and propagation of seizure activity.
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Affiliation(s)
- Luisa Rocha
- Departamento de Farmacobiología, Sede Sur del Centro de Investigación y de Estudios Avanzados, Calz. Tenorios 235, Col. Granjas Coapa, C.P. 14330, México, DF, Mexico.
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Goldsmith P, Golder Z, Hunt J, Berghmans S, Jones D, Stables JP, Murphree L, Howden D, Newton PE, Richards FM. GBR12909 Possesses Anticonvulsant Activity in Zebrafish and Rodent Models of Generalized Epilepsy but Cardiac Ion Channel Effects Limit Its Clinical Utility. Pharmacology 2007; 79:250-8. [PMID: 17476122 DOI: 10.1159/000102061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Accepted: 12/06/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS GBR12909 has been reported to possess anticonvulsant activity with focal brain perfusion to the hippocampus of pilocarpine, although an earlier publication suggested any anticonvulsant effects were only mild. Here we further explored the anticonvulsant potential of GBR12909 with a suite of anticonvulsant assays in both zebrafish and mammals and then explored whether it possessed any QT effects which might limit clinical utility. METHODS We assessed the anticonvulsant effects of GBR12909 in zebrafish pentylenetetrazole (PTZ), mammalian maximal electroshock and PTZ models of generalized epilepsy and a rodent hippocampal kindling model. Cardiac effects were assessed in zebrafish and man. RESULTS GBR12909 possesses anticonvulsant activity in zebrafish and rodent models of generalized epilepsy. However, phase 1 human data indicated potential QT effects. Subsequent testing in a zebrafish QT assay confirmed marked arrhythmogenic potential. CONCLUSION Further clinical development of GBR12909 in epilepsy was considered inappropriate because of insufficient window between the therapeutic effects and the cardiac arrhythmia problems identified in zebrafish assays. Any further development based on this mechanism of action should avoid the GBR12909 chemical scaffold, or involve structure-activity dissociation of its neurological and cardiac effects.
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Kim DS, Kim JE, Kwak SE, Kim DW, Choi SY, Kwon OS, Kang TC. Seizure activity selectively reduces 5-HT1A receptor immunoreactivity in CA1 interneurons in the hippocampus of seizure-prone gerbils. Brain Res 2007; 1154:181-93. [PMID: 17493597 DOI: 10.1016/j.brainres.2007.03.084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 03/29/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Since the correlation between the serotonin (5-hydroxytryptamine, 5-HT) system and seizure activity remains to be clarified, we investigated the 5-HT system in the hippocampus of seizure-resistant (SR) and seizure-sensitive (SS) gerbils. There was no difference of the 5-HT system in the hippocampi of young animals (predisposed and juvenile gerbils) in both SR and SS gerbils. 5-HT immunoreactivity in the dorsal raphe nucleus and the median raphe nucleus was also similarly detected in both animal groups. As compared to SR adult gerbils, only 5-HT1A receptor immunoreactivity was selectively reduced in CA1 interneurons within SS adult gerbils. (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin (a 5-HT1A receptor agonist, 1 and 2 mg/kg) markedly reduced paired-pulse inhibition in the CA1 region of SS adult gerbils only. These findings suggest that the selective reduction in 5-HT1A receptor expression on CA1 interneurons of SS adult gerbil may not be developmental defects, but be an acquired compensatory change induced by repeated seizure activity.
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Affiliation(s)
- Duk-Soo Kim
- Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, South Korea
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Abstract
In recent years, there has been increasing evidence that serotonergic neurotransmission modulates a wide variety of experimentally induced seizures. Generally, agents that elevate extracellular serotonin (5-HT) levels, such as 5-hydroxytryptophan and serotonin reuptake blockers, inhibit both focal and generalized seizures, although exceptions have been described, too. Conversely, depletion of brain 5-HT lowers the threshold to audiogenically, chemically and electrically evoked convulsions. Furthermore, it has been shown that several anti-epileptic drugs increase endogenous extracellular 5-HT concentration. 5-HT receptors are expressed in almost all networks involved in epilepsies. Currently, the role of at least 5-HT(1A), 5-HT(2C), 5-HT(3) and 5-HT(7) receptor subtypes in epileptogenesis and/or propagation has been described. Mutant mice lacking 5-HT(1A) or 5-HT(2C) receptors show increased seizure activity and/or lower threshold. In general, hyperpolarization of glutamatergic neurons by 5-HT(1A) receptors and depolarization of GABAergic neurons by 5-HT(2C) receptors as well as antagonists of 5-HT(3) and 5-HT(7) receptors decrease the excitability in most, but not all, networks involved in epilepsies. Imaging data and analysis of resected tissue of epileptic patients, and studies in animal models all provide evidence that endogenous 5-HT, the activity of its receptors, and pharmaceuticals with serotonin agonist and/or antagonist properties play a significant role in the pathogenesis of epilepsies.
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Affiliation(s)
- Gyorgy Bagdy
- Laboratory of Neurochemistry and Experimental Medicine, National Institute of Psychiatry and Neurology, Budapest, Hungary.
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Nurten A, Enginar N. The evaluation of antimuscarinic-induced convulsions in fasted rats after food intake. Epilepsy Res 2006; 72:171-7. [PMID: 16962289 DOI: 10.1016/j.eplepsyres.2006.07.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Revised: 07/25/2006] [Accepted: 07/26/2006] [Indexed: 11/16/2022]
Abstract
The present study was performed to evaluate convulsions after food intake in fasted rats pretreated with scopolamine or atropine and to determine whether these convulsions respond to drugs found effective in fasted mice. Scopolamine (2.4 mg/kg) and atropine (2.4 mg/kg) were given intraperitoneally (i.p.) to rats fasted for 52h. Both drugs induced convulsions after animals were allowed to eat ad lib. Another group of fasted rats pretreated with saline, MK-801 (0.1mg/kg), clonidine (0.1mg/kg), chlorpromazine (2 and 4 mg/kg), valproate (200mg/kg), diazepam (1.5 and 2mg/kg) or gabapentin (50mg/kg) were treated i.p. with saline or scopolamine (2.4 mg/kg) and were allowed to eat ad lib. Clonidine, MK-801, chlorpromazine (4 mg/kg) and diazepam (2 mg/kg) reduced the incidence of scopolamine-induced convulsions in fasted rats. Gabapentin could only prolong the onset of convulsions. Neither treatment was effective against myoclonus of hindlimbs. Present results showed that fasted rats also develop antimuscarinic-induced convulsions which do not completely respond to treatments found effective in convulsions of fasted mice.
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Affiliation(s)
- Asiye Nurten
- Department of Neuroscience, Institute for Experimental Medicine (DETAE), Istanbul University, Istanbul, Turkey
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Höcht C, Opezzo JAW, Taira CA. Applicability of reverse microdialysis in pharmacological and toxicological studies. J Pharmacol Toxicol Methods 2006; 55:3-15. [PMID: 16567112 DOI: 10.1016/j.vascn.2006.02.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Accepted: 02/15/2006] [Indexed: 10/24/2022]
Abstract
A recent application of microdialysis is the introduction of a substance into the extracellular space via the microdialysis probe. The inclusion of a higher amount of a drug in the perfusate allows the drug to diffuse through the microdialysis membrane to the tissue. This technique, actually called as reverse microdialysis, not only allows the local administration of a substance but also permits the simultaneous sampling of the extracellular levels of endogenous compounds. Local effects of exogenous compounds have been studied in the central nervous system, hepatic tissue, dermis, heart and corpora luteae of experimental animals by means of reverse microdialysis. In central nervous studies, reverse microdialysis has been extensively used for the study of the effects on neurotransmission at different central nuclei of diverse pharmacological and toxicological agents, such as antidepressants, antipsychotics, antiparkinsonians, hallucinogens, drugs of abuse and experimental drugs. In the clinical setting, reverse microdialysis has been used for the study of local effects of drugs in the adipose tissue, skeletal muscle and dermis. The aim of this review is to describe the principles of the reverse microdialysis, to compare the technique with other available methods and finally to describe the applicability of reverse microdialysis in the study of drugs properties both in basic and clinical research.
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Affiliation(s)
- Christian Höcht
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, (C1113AAD) Buenos Aires, Argentina.
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Lanckmans K, Clinckers R, Van Eeckhaut A, Sarre S, Smolders I, Michotte Y. Use of microbore LC-MS/MS for the quantification of oxcarbazepine and its active metabolite in rat brain microdialysis samples. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 831:205-12. [PMID: 16386473 DOI: 10.1016/j.jchromb.2005.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Revised: 10/24/2005] [Accepted: 12/05/2005] [Indexed: 11/18/2022]
Abstract
A microbore LC-MS/MS method is developed and validated for the quantification of the anti-epileptic drug oxcarbazepine (OXC) and its active metabolite 10,11-dihydro-10-hydroxycarbamazepine (MHD) in rat brain microdialysates, together with the internal standard for microdialysis probe calibration, 2-methyl-5H-dibenz(b,f)azepine-5-carboxamide (m-CBZ). The benefits of gradient versus isocratic separation are shown, next to the improved sensitivity resulting from the addition of 0.1% formic acid to the mobile phase. The coupling of microdialysis with ESI-MS requires sample desalting for which column switching was applied. Using weighed regression to calculate the calibration curves (1-1000 ng/mL), the assay was validated in terms of linearity, accuracy and precision, yielding a sensitive (limit of quantification is 1 ng/mL) and selective method for quantification of OXC, MHD and m-CBZ. By applying this method, we were able to determine the extracellular concentrations of OXC and MHD during at least 4h after intraperitoneal (i.p.) administration of 10 mg/kg OXC.
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Affiliation(s)
- Katrien Lanckmans
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
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Clinckers R, Smolders I, Meurs A, Ebinger G, Michotte Y. Hippocampal dopamine and serotonin elevations as pharmacodynamic markers for the anticonvulsant efficacy of oxcarbazepine and 10,11-dihydro-10-hydroxycarbamazepine. Neurosci Lett 2005; 390:48-53. [PMID: 16139430 DOI: 10.1016/j.neulet.2005.07.049] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 07/27/2005] [Accepted: 07/29/2005] [Indexed: 11/18/2022]
Abstract
We recently showed that dopamine (DA) and serotonin (5-HT) exert anticonvulsant effects against limbic seizures in rats mediated by hippocampal D(2) and 5-HT(1A) receptor stimulation. For exogenously administered monoamines, anticonvulsant activity was only observed following 70--400% and 80--350% increases in baseline levels for dopamine and serotonin, respectively. The aim of the present microdialysis study was to investigate whether oxcarbazepine and its active metabolite, 10,11-dihydro-10-hydroxycarbamazepine (MHD) promote the release of hippocampal monoamines. Initially, concentration-response experiments were performed. Different concentrations of both compounds were perfused into the hippocampus via the microdialysis probe and tested for their effects on extracellular monoamine levels and anticonvulsant properties against pilocarpine-evoked seizures in rats. Anticonvulsant activity was always accompanied by significant increases in dopamine and serotonin levels. The anticonvulsant threshold concentrations for oxcarbazepine (100 microM) and 10,11-dihydro-10-hydroxycarbamazepine (250 microM) were associated with, respectively, 140 and 205% increases in hippocampal dopamine and 288 and 176% increases in serotonin concentrations. Co-perfusion of these anticonvulsant threshold concentrations for both compounds either with a selective D(2) or 5-HT(1A) antagonist abolished all anticonvulsant effects. This study shows that oxcarbazepine and 10,11-dihydro-10-hydroxycarbamazepine exert important monoamine promoting effects that, at least partly, contribute to the anticonvulsant mechanism of action of these compounds. The effects on dopamine and serotonin levels are therefore proposed as pharmacodynamic markers for the anticonvulsant activity of these compounds. These pharmacodynamic markers are here shown to be useful for the selection of anticonvulsant threshold concentrations of oxcarbazepine and 10,11-dihydro-10-hydroxycarbamazepine.
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Affiliation(s)
- Ralph Clinckers
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
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Clinckers R, Gheuens S, Smolders I, Meurs A, Ebinger G, Michotte Y. In vivo modulatory action of extracellular glutamate on the anticonvulsant effects of hippocampal dopamine and serotonin. Epilepsia 2005; 46:828-36. [PMID: 15946324 DOI: 10.1111/j.1528-1167.2005.57004.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE Our recent work (Clinckers et al., J Neurochem 2004;89:834-43) demonstrated that intrahippocampal perfusion of 2 nM dopamine or serotonin via a microdialysis probe offered complete protection against focal pilocarpine-induced limbic seizures and did not influence basal extracellular hippocampal glutamate levels. Ten nanomolar dopamine or serotonin perfusion, however, worsened seizures and was accompanied by significant extracellular glutamate increases to approximately 200%. The significance of these glutamate elevations in seizure generation remains unclear. The present microdialysis study investigated the modulatory role of extracellular hippocampal glutamate levels in these monoaminergic protective and proconvulsant effects. METHODS A first group of male Wistar albino rats was perfused intrahippocampally for 240 min with 6.25 microM glutamate alone to increase extracellular levels by 200%. Other animals were perfused with anticonvulsant concentrations of monoamines throughout the experiments while receiving continuous coperfusions of 6.25 microM glutamate either before, during, and after (240 min) or only after (100 min) pilocarpine perfusion (40 min). Rats were scored for epileptic behavior, and the mean scores were compared with those of the control group. Microdialysates were analyzed for monoamine and glutamate content with microbore liquid chromatography. RESULTS No convulsions occurred during glutamate perfusion alone. When monoamines and glutamate were coperfused before pilocarpine administration, the anticonvulsant effect of the monoamines was lost. Glutamate addition after pilocarpine administration did not affect monoaminergic seizure protection. CONCLUSIONS These results indicate that extracellular glutamate increases per se do not necessarily induce seizures but that they can modulate the anticonvulsant effects exerted by hippocampal monoamines.
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Affiliation(s)
- Ralph Clinckers
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Brussels, Belgium
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Clinckers R, Smolders I, Meurs A, Ebinger G, Michotte Y. Quantitative in Vivo Microdialysis Study on the Influence of Multidrug Transporters on the Blood-Brain Barrier Passage of Oxcarbazepine: Concomitant Use of Hippocampal Monoamines as Pharmacodynamic Markers for the Anticonvulsant Activity. J Pharmacol Exp Ther 2005; 314:725-31. [PMID: 15860570 DOI: 10.1124/jpet.105.085514] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Various antiepileptic drugs were shown to be substrates for multidrug transporters at the level of the blood-brain barrier. These ATP-dependent efflux pumps actively limit brain accumulation of xenobiotics and drugs. Intrahippocampal oxcarbazepine perfusion in rat was previously shown to exert anticonvulsant effects associated with increases in extracellular dopamine and serotonin levels. In contrast, preliminary studies in our laboratory revealed that no anticonvulsant or monoaminergic effects could be obtained after systemic oxcarbazepine administration. The present in vivo microdialysis study was conducted to investigate the impact of the transport kinetics of oxcarbazepine across the blood-brain barrier on the observed treatment refractoriness. More precisely, the influence of intrahippocampal perfusion of verapamil, a P-glycoprotein inhibitor, and probenecid, a multidrug resistance protein inhibitor, on the blood-brain barrier passage and anticonvulsant properties of oxcarbazepine were investigated in the focal pilocarpine model for limbic seizures. Simultaneously, the effects on hippocampal monoamines were studied as pharmacodynamic markers for the anticonvulsant activity. Although systemic oxcarbazepine administration alone failed in preventing the animals from developing seizures, coadministration with verapamil or probenecid offered complete protection. Concomitantly, significant increases in extracellular hippocampal dopamine and serotonin levels were observed within our previously defined anticonvulsant monoamine range. The present data indicate that oxcarbazepine is a substrate for multidrug transporters at the blood-brain barrier. Coadministration with multidrug transporter inhibitors significantly potentiates the anticonvulsant activity of oxcarbazepine and offers opportunities for treatment of pharmacoresistant epilepsy.
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Affiliation(s)
- Ralph Clinckers
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium
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