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Abdelaal MS, Kato T, Natsubori A, Tanaka KF. Temporal and Potential Predictive Relationships between Sleep Spindle Density and Spike-and-Wave Discharges. eNeuro 2024; 11:ENEURO.0058-24.2024. [PMID: 39256042 PMCID: PMC11412100 DOI: 10.1523/eneuro.0058-24.2024] [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: 01/16/2024] [Revised: 08/27/2024] [Accepted: 08/29/2024] [Indexed: 09/12/2024] Open
Abstract
Spike-and-wave discharges (SWDs) and sleep spindles are characteristic electroencephalographic (EEG) hallmarks of absence seizures and nonrapid eye movement sleep, respectively. They are commonly generated by the cortico-thalamo-cortical network including the thalamic reticular nucleus (TRN). It has been reported that SWD development is accompanied by a decrease in sleep spindle density in absence seizure patients and animal models. However, whether the decrease in sleep spindle density precedes, coincides with, or follows, the SWD development remains unknown. To clarify this, we exploited Pvalb-tetracycline transactivator (tTA)::tetO-ArchT (PV-ArchT) double-transgenic mouse, which can induce an absence seizure phenotype in a time-controllable manner by expressing ArchT in PV neurons of the TRN. In these mice, EEG recordings demonstrated that a decrease in sleep spindle density occurred 1 week before the onset of typical SWDs, with the expression of ArchT. To confirm such temporal relationship observed in these genetic model mice, we used a gamma-butyrolactone (GBL) pharmacological model of SWDs. Prior to GBL administration, we administered caffeine to wild-type mice for 3 consecutive days to induce a decrease in sleep spindle density. We then administered low-dose GBL, which cannot induce SWDs in normally conditioned mice but led to the occurrence of SWDs in caffeine-conditioned mice. These findings indicate a temporal relationship in which the decrease in sleep spindle density consistently precedes SWD development. Furthermore, the decrease in sleep spindle activity may have a role in facilitating the development of SWDs. Our findings suggest that sleep spindle reductions could serve as early indicators of seizure susceptibility.
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Affiliation(s)
- Manal S Abdelaal
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Tomonobu Kato
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
- Department of System Design Engineering, Faculty of Science and Technology, Keio University, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Akiyo Natsubori
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-Ku, Tokyo 156-8506, Japan
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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Yavuz M, Akkol S, Onat F. Alpha-2a adrenergic receptor activation in genetic absence epilepsy: An absence status model? Epilepsia Open 2024; 9:534-547. [PMID: 38071480 PMCID: PMC10984306 DOI: 10.1002/epi4.12879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 12/07/2023] [Indexed: 04/04/2024] Open
Abstract
OBJECTIVE The objective of the study was to propose a candidate animal model of absence status epilepticus induced by specific alpha-2a adrenergic receptor (α2AR) activation. We also aim to investigate the responsiveness of this model to classical anti-status or anti-absence medications. METHODS An α2AR agonist, dexmedetomidine (DEX), was injected intracerebroventricularly into adult rats with genetic absence epilepsy, and their electroencephalography (EEG) was recorded. The total duration, number, and mean duration of each spike-and-wave discharges (SWDs) were evaluated. The blocks of absence status events were classified as the initial and second sets of absence statuses. Ethosuximide (ETX) was administered as a pretreatment to another group of rats and later injected with 2.5 μg DEX. In addition, ETX, valproic acid (VPA), diazepam (DIAZ), and atipamezole (ATI) were administered after induced status-like events following DEX administration. Power spectral characteristics and coherence analysis were performed on the EEG to assess the absence status events and sleep. RESULTS The 2.5 μg dose of DEX increased the total SWD duration and induced continuous SWDs up to 26 min. Following the initial absence status event, sleep was induced; then, the second period of absence status-like activities were initiated. ETX pretreatment blocked the occurrence of absence status-like activities. Power spectral density analyses revealed that DEX-induced post-sleep activities had higher power in delta frequency band (1-4 Hz) and attenuated power of 7 Hz harmonics (14 and 21 Hz) than the pre-injection seizure. The mean duration of SWDs were decreased in all the groups, but occasional prolonged activities were seen in ETX or VPA-injected rats but not with DIAZ or ATI. SIGNIFICANCE This study presents an absence status epilepticus animal model that is activated by α2AR activation to investigate the pathophysiological role of absence status. Unlike other agents ATI switched off the second set of absence statuses to normal SWDs, without sedation or lethargy, can show it may preferentially block absence status-like activity. THE PLAIN LANGUAGE SUMMARY This study proposes a rat model for prolonged seizures, resembling absence status epilepticus. Activating the brain's alpha-2a adrenergic receptor with dexmedetomidine induced seizures lasting up to 26 minutes. Ethosuximide pretreatment and post-treatment with valproic acid, diazepam, and atipamezole decreased induced seizures. The findings suggest this model is valuable for studying absence status epilepticus. In addition, atipamezole normalized abnormal seizures without sedation, hinting at its potential for targeted treatment and further research.
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Affiliation(s)
- Melis Yavuz
- Department of Pharmacology, Faculty of PharmacyAcibadem Mehmet Ali Aydinlar University UniversityIstanbulTurkey
| | - Serdar Akkol
- Department of NeurologyUniversity of Alabama at Birmingham Medical CenterBirminghamAlabamaUSA
| | - Filiz Onat
- Department of Medical Pharmacology, School of MedicineMarmara UniversityIstanbulTurkey
- Department of Medical Pharmacology, School of MedicineAcibadem Mehmet Ali Aydinlar UniversityIstanbulTurkey
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Yavuz M, İyiköşker P, Mutlu N, Kiliçparlar S, Şalci ÖH, Dolu G, Kaymakçilar EN, Akkol S, Onat F. Dexmedetomidine, an alpha 2A receptor agonist, triggers seizures unilaterally in GAERS during the pre-epileptic phase: does the onset of spike-and-wave discharges occur in a focal manner? Front Neurol 2023; 14:1231736. [PMID: 38146441 PMCID: PMC10749324 DOI: 10.3389/fneur.2023.1231736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 11/13/2023] [Indexed: 12/27/2023] Open
Abstract
Introduction The genetic absence epilepsy rat from Strasbourg (GAERS) is a rat model for infantile absence epilepsy with spike-and-wave discharges (SWDs). This study aimed to investigate the potential of alpha 2A agonism to induce seizures during the pre-epileptic period in GAERS rats. Methods Stereotaxic surgery was performed on male pups and adult GAERS rats to implant recording electrodes in the frontoparietal cortices (right/left) under anesthesia (PN23-26). Following the recovery period, pup GAERS rats were subjected to electroencephalography (EEG) recordings for 2 h. Before the injections, pup epileptiform activity was examined using baseline EEG data. Dexmedetomidine was acutely administered at 0.6 mg/kg to pup GAERS rats 2-3 days after the surgery and once during the post-natal (PN) days 25-29. Epileptiform activities before injections triggered unilateral SWDs and induced sleep durations, and power spectral density was evaluated based on EEG traces. Results The most prominent finding of this study is that unilateral SWD-like activities were induced in 47% of the animals with the intraperitoneal dexmedetomidine injection. The baseline EEGs of pup GAERS rats had no SWDs as expected since they are in the pre-epileptic period but showed low-amplitude non-rhythmic epileptiform activity. There was no difference in the duration of epileptiform activities between the basal EEG groups and DEX-injected unilateral SWD-like-exhibiting and non-SWD-like activities groups; however, the sleep duration of the unilateral SWD-like-exhibiting group was shorter. Power spectrum density (PSD) results revealed that the 1.75-Hz power in the left hemisphere peaks significantly higher than in the right. Discussion As anticipated, pup GAERS rats in the pre-epileptic stage showed no SWDs. Nevertheless, they exhibited sporadic epileptiform activities. Specifically, dexmedetomidine induced SWD-like activities solely within the left hemisphere. These observations imply that absence seizures might originate unilaterally in the left cortex due to α2AAR agonism. Additional research is necessary to explore the precise cortical focal point of this activity.
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Affiliation(s)
- Melis Yavuz
- Department of Pharmacology, Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Pelin İyiköşker
- Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Nursima Mutlu
- Department of Biotechnology and Genetics, Institute of Science, Istanbul University, Istanbul, Türkiye
| | - Serra Kiliçparlar
- Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Öykü Hazal Şalci
- Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | - Gökçen Dolu
- Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
| | | | - Serdar Akkol
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Filiz Onat
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
- Institute of Neurosciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye
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Jiang X, Wen X, Ou G, Li S, Chen Y, Zhang J, Liang Z. Propofol modulates neural dynamics of thalamo-cortical system associated with anesthetic levels in rats. Cogn Neurodyn 2023; 17:1541-1559. [PMID: 37974577 PMCID: PMC10640503 DOI: 10.1007/s11571-022-09912-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 10/14/2022] [Accepted: 10/28/2022] [Indexed: 11/24/2022] Open
Abstract
The thalamocortical system plays an important role in consciousness. How anesthesia modulates the thalamocortical interactions is not completely known. We simultaneously recorded local field potentials(LFPs) in thalamic reticular nucleus(TRN) and ventroposteromedial thalamic nucleus(VPM), and electrocorticographic(ECoG) activities in frontal and occipital cortices in freely moving rats (n = 11). We analyzed the changes in thalamic and cortical local spectral power and connectivities, which were measured with phase-amplitude coupling (PAC), coherence and multivariate Granger causality, at the states of baseline, intravenous infusion of propofol 20, 40, 80 mg/kg/h and after recovery of righting reflex. We found that propofol-induced burst-suppression results in a synchronous decrease of spectral power in thalamus and cortex (p < 0.001 for all frequency bands). The cross-frequency PAC increased by propofol, characterized by gradually stronger 'trough-max' pattern in TRN and stronger 'peak-max' pattern in cortex. The cross-region PAC increased in the phase of TRN modulating the amplitude of cortex. The functional connectivity (FC) between TRN and cortex for α/β bands also significantly increased (p < 0.040), with increased directional connectivity from TRN to cortex under propofol anesthesia. In contrast, the corticocortical FC significantly decreased (p < 0.047), with decreased directional connectivity from frontal cortex to occipital cortex. However, the thalamothalamic functional and directional connectivities remained largely unchanged by propofol anesthesia. The spectral powers and connectivities are differentially modulated with the changes of propofol doses, suggesting the changes in neural dynamics in thalamocortical system could be used for distinguishing different vigilance levels caused by propofol. Supplementary Information The online version contains supplementary material available at 10.1007/s11571-022-09912-0.
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Affiliation(s)
- Xuliang Jiang
- Department of Anesthesiology, Shanghai Cancer Center, Fudan University, Shanghai, 200032 People’s Republic of China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 People’s Republic of China
| | - Xin Wen
- Institute of Electrical Engineering, Yanshan University, Qinhuangdao, 066004 People’s Republic of China
- Key Laboratory of Intelligent Rehabilitation and Neuromodulation of Hebei Province, Qinhuangdao, 066004 People’s Republic of China
| | - Guoyao Ou
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040 People’s Republic of China
| | - Shitong Li
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040 People’s Republic of China
| | - Yali Chen
- Department of Anesthesiology, Shanghai Cancer Center, Fudan University, Shanghai, 200032 People’s Republic of China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 People’s Republic of China
| | - Jun Zhang
- Department of Anesthesiology, Shanghai Cancer Center, Fudan University, Shanghai, 200032 People’s Republic of China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 People’s Republic of China
| | - Zhenhu Liang
- Institute of Electrical Engineering, Yanshan University, Qinhuangdao, 066004 People’s Republic of China
- Key Laboratory of Intelligent Rehabilitation and Neuromodulation of Hebei Province, Qinhuangdao, 066004 People’s Republic of China
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Sarkisova KY, Gabova AV, Fedosova EA, Shatskova AB, Narkevich VB, Kudrin VS. Antidepressant and Anxiolytic Effects of L-Methionine in the WAG/Rij Rat Model of Depression Comorbid with Absence Epilepsy. Int J Mol Sci 2023; 24:12425. [PMID: 37569798 PMCID: PMC10419169 DOI: 10.3390/ijms241512425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
Depression is a severe and widespread psychiatric disease that often accompanies epilepsy. Antidepressant treatment of depression comorbid with epilepsy is a major concern due to the risk of seizure aggravation. SAMe, a universal methyl donor for DNA methylation and the synthesis of brain monoamines, is known to have high antidepressant activity. This study aimed to find out whether L-methionine (L-MET), a precursor of SAMe, can have antidepressant and/or anxiolytic effects in the WAG/Rij rat model of depression comorbid with absence epilepsy. The results indicate that L-MET reduces the level of anxiety and depression in WAG/Rij rats and suppresses associated epileptic seizures, in contrast to conventional antidepressant imipramine, which aggravates absence seizures. The antidepressant effect of L-MET was comparable with that of the conventional antidepressants imipramine and fluoxetine. However, the antidepressant profile of L-MET was more similar to imipramine than to fluoxetine. Taken together, our findings suggest that L-MET could serve as a promising new antidepressant drug with anxiolytic properties for the treatment of depression comorbid with absence epilepsy. Increases in the level of monoamines and their metabolites-DA, DOPAC, HVA, NA, and MHPG-in several brain structures, is suggested to be a neurochemical mechanism of the beneficial phenotypic effect of L-MET.
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Affiliation(s)
- Karine Yu. Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str. 5A, Moscow 117485, Russia; (A.V.G.); (E.A.F.); (A.B.S.)
| | - Alexandra V. Gabova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str. 5A, Moscow 117485, Russia; (A.V.G.); (E.A.F.); (A.B.S.)
| | - Ekaterina A. Fedosova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str. 5A, Moscow 117485, Russia; (A.V.G.); (E.A.F.); (A.B.S.)
| | - Alla B. Shatskova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str. 5A, Moscow 117485, Russia; (A.V.G.); (E.A.F.); (A.B.S.)
| | - Victor B. Narkevich
- Federal State Budgetary Institution “Scientific Research Institute of Pharmacology named after V.V. Zakusov”, Baltiyskaya Str. 8, Moscow 125315, Russia; (V.B.N.); (V.S.K.)
| | - Vladimir S. Kudrin
- Federal State Budgetary Institution “Scientific Research Institute of Pharmacology named after V.V. Zakusov”, Baltiyskaya Str. 8, Moscow 125315, Russia; (V.B.N.); (V.S.K.)
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Sitnikova E, Pupikina M, Rutskova E. Alpha2 Adrenergic Modulation of Spike-Wave Epilepsy: Experimental Study of Pro-Epileptic and Sedative Effects of Dexmedetomidine. Int J Mol Sci 2023; 24:9445. [PMID: 37298397 PMCID: PMC10254047 DOI: 10.3390/ijms24119445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/20/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
In the present report, we evaluated adrenergic mechanisms of generalized spike-wave epileptic discharges (SWDs), which are the encephalographic hallmarks of idiopathic generalized epilepsies. SWDs link to a hyper-synchronization in the thalamocortical neuronal activity. We unclosed some alpha2-adrenergic mechanisms of sedation and provocation of SWDs in rats with spontaneous spike-wave epilepsy (WAG/Rij and Wistar) and in control non-epileptic rats (NEW) of both sexes. Dexmedetomidine (Dex) was a highly selective alpha-2 agonist (0.003-0.049 mg/kg, i.p.). Injections of Dex did not elicit de novo SWDs in non-epileptic rats. Dex can be used to disclose the latent form of spike-wave epilepsy. Subjects with long-lasting SWDs at baseline were at high risk of absence status after activation of alpha2- adrenergic receptors. We create the concept of alpha1- and alpha2-ARs regulation of SWDs via modulation of thalamocortical network activity. Dex induced the specific abnormal state favorable for SWDs-"alpha2 wakefulness". Dex is regularly used in clinical practice. EEG examination in patients using low doses of Dex might help to diagnose the latent forms of absence epilepsy (or pathology of cortico-thalamo-cortical circuitry).
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Affiliation(s)
- Evgenia Sitnikova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, 117485 Moscow, Russia (E.R.)
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Sitnikova E, Rutskova E, Smirnov K. Alpha2-Adrenergic Receptors as a Pharmacological Target for Spike-Wave Epilepsy. Int J Mol Sci 2023; 24:1477. [PMID: 36674992 PMCID: PMC9862736 DOI: 10.3390/ijms24021477] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Spike-wave discharges are the hallmark of idiopathic generalized epilepsy. They are caused by a disorder in the thalamocortical network. Commercially available anti-epileptic drugs have pronounced side effects (i.e., sedation and gastroenterological concerns), which might result from a low selectivity to molecular targets. We suggest a specific subtype of adrenergic receptors (ARs) as a promising anti-epileptic molecular target. In rats with a predisposition to absence epilepsy, alpha2 ARs agonists provoke sedation and enhance spike-wave activity during transitions from awake/sedation. A number of studies together with our own observations bring evidence that the sedative and proepileptic effects require different alpha2 ARs subtypes activation. Here we introduce a new concept on target pharmacotherapy of absence epilepsy via alpha2B ARs which are presented almost exclusively in the thalamus. We discuss HCN and calcium channels as the most relevant cellular targets of alpha2 ARs involved in spike-wave activity generation.
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Affiliation(s)
- Evgenia Sitnikova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, Moscow 117485, Russia
| | - Elizaveta Rutskova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, Moscow 117485, Russia
| | - Kirill Smirnov
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, Moscow 117485, Russia
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, Bld. 1, Moscow 121205, Russia
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Sere P, Zsigri N, Raffai T, Furdan S, Győri F, Crunelli V, Lőrincz ML. Activity of the Lateral Hypothalamus during Genetically Determined Absence Seizures. Int J Mol Sci 2021; 22:ijms22179466. [PMID: 34502374 PMCID: PMC8431596 DOI: 10.3390/ijms22179466] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/17/2021] [Accepted: 08/26/2021] [Indexed: 12/14/2022] Open
Abstract
(1) Background: Absence seizures (ASs) are sudden, transient lapses of consciousness associated with lack of voluntary movements and generalized 2.5–4 Hz spike-wave discharges (SWDs) in the EEG. In addition to the thalamocortical system, where these pathological oscillations are generated, multiple neuronal circuits have been involved in their modulation and associated comorbidities including the serotonergic system. Neuronal activity in one of the major synaptic input structures to the brainstem dorsal raphé nucleus (DRN), the lateral hypothalamus (LH), has not been characterized. (2) Methods: We used viral tract tracing and optogenetics combined with in vitro and in vivo electrophysiology to assess the involvement of the LH in absence epilepsy in a genetic rodent model. (3) Results: We found that a substantial fraction of LH neurons project to the DRN of which a minority is GABAergic. The LH to DRN projection can lead to monosynaptic iGluR mediated excitation in DRN 5-HT neurons. Neuronal activity in the LH is coupled to SWDs. (4) Conclusions: Our results indicate that a brain area involved in the regulation of autonomic functions and heavily innervating the RN is involved in ASs. The decreased activity of LH neurons during SWDs could lead to both a decreased excitation and disinhibition in the DRN. These results support a long-range subcortical regulation of serotonergic neuromodulation during ASs and further our understanding of the state-dependence of these seizures and some of their associated comorbidities.
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Affiliation(s)
- Péter Sere
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, 6726 Szeged, Hungary; (P.S.); (N.Z.); (T.R.); (S.F.); (F.G.)
- Department of Physiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary
| | - Nikolett Zsigri
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, 6726 Szeged, Hungary; (P.S.); (N.Z.); (T.R.); (S.F.); (F.G.)
- Department of Physiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary
| | - Timea Raffai
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, 6726 Szeged, Hungary; (P.S.); (N.Z.); (T.R.); (S.F.); (F.G.)
- Department of Physiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary
| | - Szabina Furdan
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, 6726 Szeged, Hungary; (P.S.); (N.Z.); (T.R.); (S.F.); (F.G.)
| | - Fanni Győri
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, 6726 Szeged, Hungary; (P.S.); (N.Z.); (T.R.); (S.F.); (F.G.)
| | - Vincenzo Crunelli
- Neuroscience Division, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK;
| | - Magor L. Lőrincz
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, 6726 Szeged, Hungary; (P.S.); (N.Z.); (T.R.); (S.F.); (F.G.)
- Department of Physiology, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary
- Neuroscience Division, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK;
- Correspondence:
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Yavuz M, Aydın B, Çarçak N, Akman Ö, Raci Yananlı H, Onat F. Atipamezole, a specific α 2A antagonist, suppresses spike-and-wave discharges and alters Ca 2⁺ /calmodulin-dependent protein kinase II in the thalamus of genetic absence epilepsy rats. Epilepsia 2020; 61:2825-2835. [PMID: 33098125 DOI: 10.1111/epi.16728] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 09/25/2020] [Accepted: 09/25/2020] [Indexed: 01/21/2023]
Abstract
OBJECTIVE The role of α2A adrenergic receptors (α2A ARs) in absence epilepsy is not well characterized. Therefore, we investigated the outcomes of the specific antagonism of α2A ARs on the spike-and-wave discharges (SWDs) in genetic absence epilepsy rats from Strasbourg (GAERSs), together with its influence on the behavior and second messenger systems, which may point to the mechanisms to which a possible SWD modulation can be related. METHODS Atipamezole, an α2A AR antagonist, was administered intracerebroventricularly to the adult GAERSs, and electroencephalography (EEG) was conducted. The cumulative duration and number of SWDs, and the mean duration of each SWD complex were counted. The relative power of the EEG frequency bands and behavioral activity after the acute application of two doses (12 and 31 μg/5 μL) of atipamezole were evaluated. The levels of cyclic adenosine monophosphate and calcium/calmodulin-dependent kinase II (CaMKII) were measured in the cortex, thalamus, and hippocampus of naive Wistar rats and GAERSs, administered with artificial cerebrospinal fluid (aCSF) as a vehicle, or either acute or chronic atipamezole (12 μg), the latter being administered for 5 consecutive days. RESULTS Atipamezole significantly suppressed SWDs dose-dependently, without affecting the relative power values of EEG frequency spectrum. The stereotypic activity was significantly lower in both naive Wistar rats and GAERSs receiving the highest dose (31 μg) of atipamezole compared to GAERSs receiving aCSF. In GAERSs, CaMKII levels were found to be higher in the thalamus after the acute and chronic application of SWD-suppressing doses of atipamezole (12 and 31 μg) compared to aCSF. SIGNIFICANCE This study emphasizes the α2 AR-related modulation of absence epilepsy and particularly the significance of α2 AR antagonism in suppressing SWDs. Atipamezole's SWD-suppressive actions may be through CaMKII-mediated second messenger systems in the thalamus.
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Affiliation(s)
- Melis Yavuz
- Department of Pharmacology, Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey.,Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Banu Aydın
- Department of Biophysics, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Nihan Çarçak
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Özlem Akman
- Department of Physiology, Faculty of Medicine, Demiroglu Bilim University, Istanbul, Turkey
| | - Hasan Raci Yananlı
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey
| | - Filiz Onat
- Department of Medical Pharmacology, Faculty of Medicine, Marmara University, Istanbul, Turkey.,Epilepsy Research Center, Marmara University, Istanbul, Turkey.,Department of Medical Pharmacology, Faculty of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
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Midzyanovskaya IS, Shatskova AB, MacDonald E, Luijtelaar GV, Tuomisto L. Brain Aminergic Deficiency in Absence Epileptic Rats: Dependency on Seizure Severity and Their Functional Coupling at Rest. ACTA ACUST UNITED AC 2020. [DOI: 10.4236/jbbs.2020.101003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kovács Z, Lakatos RK, Barna J, Dobolyi Á. Absence epileptic activity in Wistar Albino Glaxo Rijswijk rat mothers. Brain Res 2017; 1657:368-376. [PMID: 28065565 DOI: 10.1016/j.brainres.2017.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/16/2016] [Accepted: 01/02/2017] [Indexed: 11/27/2022]
Abstract
Absence epileptic activity was analyzed during pregnancy, the postpartum period and after weaning to establish alterations of seizures throughout the reproductive cycle. Wistar Albino Glaxo Rijswijk (WAG/Rij) rats were used in the study as a model of absence epilepsy and because their seizures do not interfere with rearing offspring. The number of spike-wave discharges (SWDs) was gradually elevated from the 19th pregnancy day to delivery. Meanwhile, the characteristics of individual SWDs did not change suggesting that SWD generation remained the same. In the postpartum and postweaning periods, the number of SWDs was not increased in the absence of pups. However, returning the pups to mothers resulted in a markedly elevated number of SWDs for 1h. If pups were taken away after 30min, the number of SWDs dropped immediately suggesting that the presence of pups increased the SWD number. The time mothers spent with the litter and in kyphosis suckling posture were in correlation with their SWD number further suggesting the importance of interaction with pups in SWD induction. Suckling elevates prolactin levels but surprisingly, its intracerebroventricular injection markedly reduced SWD number in suckled WAG/Rij mothers suggesting that the SWD-inducing effect of suckling is not mediated by prolactin. Rather, the elevated prolactin level may provide some protection against pro-epileptic effects of suckling. In conclusion, we first identified periods within the reproductive cycle with increased absence epileptic activity, implying that more attention should be devoted to epileptic activity changes in mothers.
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Affiliation(s)
- Zsolt Kovács
- Department of Zoology, University of West Hungary, Savaria Campus, Szombathely, Károlyi Gáspár tér 4., 9700, Hungary.
| | - Renáta Krisztina Lakatos
- Department of Zoology, University of West Hungary, Savaria Campus, Szombathely, Károlyi Gáspár tér 4., 9700, Hungary; Institute of Biology, University of Pécs, Pécs, Ifjúság útja 6., 7624, Hungary
| | - János Barna
- Laboratory of Neuromorphology and Human Brain Tissue Bank, Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Tűzoltó u. 58., 1094, Hungary
| | - Árpád Dobolyi
- Laboratory of Neuromorphology and Human Brain Tissue Bank, Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Tűzoltó u. 58., 1094, Hungary; MTA-ELTE NAP B Laboratory of Molecular and Systems Neurobiology, Institute of Biology, Hungarian Academy of Sciences and Eötvös Loránd University, Budapest, Pázmány Péter sétány 1C, 1117, Hungary.
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Russo E, Citraro R, Constanti A, Leo A, Lüttjohann A, van Luijtelaar G, De Sarro G. Upholding WAG/Rij rats as a model of absence epileptogenesis: Hidden mechanisms and a new theory on seizure development. Neurosci Biobehav Rev 2016; 71:388-408. [DOI: 10.1016/j.neubiorev.2016.09.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 09/19/2016] [Indexed: 02/06/2023]
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13
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Impaired glutamatergic and GABAergic transmission by amitraz in primary hippocampal cells. Neurotoxicol Teratol 2015; 50:82-7. [DOI: 10.1016/j.ntt.2015.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 06/18/2015] [Accepted: 06/25/2015] [Indexed: 12/31/2022]
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14
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Kovács Z, Czurkó A, Kékesi KA, Juhász G. Neonatal tricyclic antidepressant clomipramine treatment reduces the spike-wave discharge activity of the adult WAG/Rij rat. Brain Res Bull 2012; 89:102-7. [PMID: 22884691 DOI: 10.1016/j.brainresbull.2012.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 06/19/2012] [Accepted: 07/29/2012] [Indexed: 11/15/2022]
Abstract
Recently it was revealed that the absence-like epileptic activity of the WAG/Rij (Wistar Albino Glaxo/Rijswijk) rat is associated with depression-like behavioural symptoms. Whether these depressive-like symptoms are accompanying epileptic activity (manifested in spike-wave discharges, SWDs, in the EEG) or whether they are causative for each other are open questions. Neonatally administered tricyclic antidepressant clomipramine is a well characterized animal model of major depression. It evokes behavioural symptoms of depression and changes sleep pattern in normal adult rats. We investigated whether in the WAG/Rij rat the neonatally administered clomipramine would aggravate the depression-like behavioural symptoms and the SWD activity. Male WAG/Rij pups from postnatal day 8 (PD8) to PD21 were treated with clomipramine (20mg/kg) or saline (control animals) twice daily intraperitoneally (i.p.). In the 8 months old rats, sleep parameters and sucrose solution intake (as hedonic index) as well as the SWD activity were measured. While the neonatal clomipramine treatment significantly increased the rapid eye movement sleep (REM) amount and decreased the sucrose preference score, it surprisingly attenuated the adult (8 months old) SWD activity. We concluded that neonatal clomipramine treatment produced aggravation of depression-like symptoms while decreased the SWD activity in the adult (8 months old) WAG/Rij rat.
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Affiliation(s)
- Zsolt Kovács
- Department of Zoology, University of West Hungary, Savaria Campus, Károlyi Gáspár tér 4, Szombathely 9700, Hungary.
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15
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Tolmacheva EA, Oitzl MS, van Luijtelaar G. Stress, glucocorticoids and absences in a genetic epilepsy model. Horm Behav 2012; 61:706-10. [PMID: 22465594 DOI: 10.1016/j.yhbeh.2012.03.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 03/14/2012] [Accepted: 03/15/2012] [Indexed: 11/20/2022]
Abstract
Although stress can alter the susceptibility of patients and animal models to convulsive epilepsy, little is known about the role of stress and glucocorticoid hormones in absence epilepsy. We measured the basal and acute stress-induced (foot-shocks: FS) concentrations of corticosterone in WAG/Rij rats, non-epileptic inbred ACI rats and outbred Wistar rats. The WAG/Rij strain is a genetic model for absence epilepsy and comorbidity for depression, which originates from the population of Wistar rats and, therefore, shares their genetic background. In a separate experiment, WAG/Rij rats were exposed to FS on three consecutive days. Electroencephalograms (EEGs) were recorded before and after FS, and the number of absence seizures (spike-wave-discharges, SWDs) was quantified. Both WAG/Rij rats and ACI rats exhibited elevated basal levels of corticosterone and a rapid corticosterone increase in response to acute stress. The WAG/Rij rats also displayed the most rapid normalization of corticosterone during the recovery phase compared to that of ACI and Wistar rats. FS had a biphasic effect on SWDs; an initial suppression was followed by an aggravation of the SWDs. By the third day, this aggravation of seizures was present in the hour preceding FS. This increase in SWDs may arise from anticipatory stress about the upcoming FS. Together, these results suggest that the distinct secretion profile of corticosterone found in WAG/Rij rats may contribute to the severity of the epileptic phenotype. Although the acute stressor results in an initial suppression of SWDs followed by an increase in SWDs, stress prior to a predictable negative event aggravates absences.
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MESH Headings
- Animals
- Circadian Rhythm/physiology
- Corticosterone/blood
- Disease Models, Animal
- Electric Stimulation/methods
- Electroencephalography
- Epilepsy/blood
- Epilepsy/complications
- Epilepsy/genetics
- Epilepsy, Absence/blood
- Epilepsy, Absence/etiology
- Epilepsy, Absence/genetics
- Epilepsy, Absence/pathology
- Glucocorticoids/analysis
- Glucocorticoids/blood
- Male
- Rats
- Rats, Transgenic
- Rats, Wistar
- Stress, Psychological/blood
- Stress, Psychological/etiology
- Stress, Psychological/genetics
- Stress, Psychological/pathology
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Affiliation(s)
- Elena A Tolmacheva
- Biological Psychology, DCC, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
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16
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The prevention of behavioral consequences of idiopathic generalized epilepsy: Evidence from rodent models. Neurosci Lett 2011; 497:177-84. [DOI: 10.1016/j.neulet.2011.02.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 02/15/2011] [Indexed: 12/29/2022]
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17
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Kovács Z, Czurkó A, Kékesi KA, Juhász G. Clomipramine increases the incidence and duration of spike-wave discharges in freely moving WAG/Rij rats. Epilepsy Res 2010; 90:167-70. [DOI: 10.1016/j.eplepsyres.2010.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/19/2010] [Accepted: 02/22/2010] [Indexed: 01/22/2023]
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18
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Sarkisova KY, Kuznetsova GD, Kulikov MA, van Luijtelaar G. Spike-wave discharges are necessary for the expression of behavioral depression-like symptoms. Epilepsia 2009; 51:146-60. [PMID: 19674046 DOI: 10.1111/j.1528-1167.2009.02260.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE The WAG/Rij strain of rats, a well-established model for absence epilepsy, has comorbidity for depression. These rats exhibit depression-like behavioral symptoms such as increased immobility in the forced swimming test and decreased sucrose intake and preference (anhedonia). These depression-like behavioral symptoms are evident in WAG/Rij rats, both at 3-4 and 5-6 months of age, with a tendency to aggravate in parallel with an increase in seizure duration. Here we investigated whether the behavioral symptoms of depression could be prevented by the suppression of absence seizures. METHODS Ethosuximide (ETX; 300 mg/kg/day, in the drinking water) was chronically applied to WAG/Rij rats from postnatal day 21 until 5 months. Behavioral tests were done before the cessation of the treatment. Electroencephalography (EEG) recordings were made before and after cessation of treatment to measure seizure severity at serial time-points. RESULTS ETX-treated WAG/Rij rats exhibited no symptoms of depression-like behavior in contrast to untreated WAG/Rij rats of the same age. Moreover, treated WAG/Rij rats did not differ from control age-matched Wistar rats. ETX treatment led to almost complete suppression of spike-wave discharges (SWDs) in 5-6 month old WAG/Rij rats. Discontinuation of chronic treatment was accompanied by a gradual emergence of SWDs; however, a persistent reduction in seizure activity was still present 47 days after discontinuation of the chronic treatment. DISCUSSION The results suggest that seizure activity is necessary for the expression of depression-like behavioral symptoms and confirm that epileptogenesis can be prevented by early and chronic treatment.
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Affiliation(s)
- Karine Yu Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Butlerov street 5A, Moscow 117485, Russia.
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19
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Vinogradova LV. Audiogenic kindling in Wistar and WAG/Rij rats: Kindling-prone and kindling-resistant subpopulations. Epilepsia 2008; 49:1665-74. [DOI: 10.1111/j.1528-1167.2008.01617.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Boucetta S, Chauvette S, Bazhenov M, Timofeev I. Focal generation of paroxysmal fast runs during electrographic seizures. Epilepsia 2008; 49:1925-40. [PMID: 18616553 DOI: 10.1111/j.1528-1167.2008.01707.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE A cortically generated Lennox-Gastaut type seizure is associated with spike-wave/poly-spike-wave discharges at 1.0-2.5 Hz and fast runs at 7-16 Hz. Here we studied the patterns of synchronization during runs of paroxysmal fast spikes. METHODS Electrographic activities were recorded using multisite intracellular and field potential recordings in vivo from cats anesthetized with ketamine-xylazine. In different experiments, the recording electrodes were located either at short distances (<1 mm) or at longer distances (up to 12 mm). The main experimental findings were tested in computational models. RESULTS In the majority of cases, the onset and the offset of fast runs occurred almost simultaneously in different recording sites. The amplitude and duration of fast runs could vary by orders of magnitude. Within the fast runs, the patterns of synchronization recorded in different electrodes were as following: (1) synchronous, in phase, (2) synchronous, with phase shift, (3) patchy, repeated in phase/phase shift transitions, and (4) nonsynchronous, slightly different frequencies in different recording sites or absence of oscillatory activity in one of the recording sites; the synchronous patterns (in phase or with phase shifts) were most common. All these patterns could be recorded in the same pair of electrodes during different seizures, and they were reproduced in a computational network model. Intrinsically bursting (IB) neurons fired more spikes per cycle than any other neurons suggesting their leading role in the fast run generation. CONCLUSIONS Once started, the fast runs are generated locally with variable correlations between neighboring cortical foci.
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Affiliation(s)
- Sofiane Boucetta
- Department of Anatomy and Physiology Laval University, Quebec, Canada
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Feron FJM, Hendriksen JGM, Nicolai J, Vles JSH. New-onset seizures: a possible association with clonidine? Pediatr Neurol 2008; 38:147-9. [PMID: 18206800 DOI: 10.1016/j.pediatrneurol.2007.09.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 07/03/2007] [Accepted: 09/26/2007] [Indexed: 11/25/2022]
Abstract
Clonidine is used as second-line medication for the treatment of attention deficit hyperactivity disorder in children. Product information concerning clonidine reported seizures only after overdosage of clonidine, and the prescription of clonidine has not been contraindicated in patients with known epilepsy. The present case report discusses a possible association of clonidine with new-onset seizures, in the context of status epilepticus in a 9-year-old girl.
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Affiliation(s)
- Frans J M Feron
- Youth Health Care Division, Regional Public Health Institute Maastricht, Department of Child Neurology, University Hospital Maastricht, The Netherlands.
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22
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Citraro R, Russo E, Gratteri S, Di Paola ED, Ibbadu GF, Curinga C, Gitto R, Chimirri A, Donato G, De Sarro G. Effects of non-competitive AMPA receptor antagonists injected into some brain areas of WAG/Rij rats, an animal model of generalized absence epilepsy. Neuropharmacology 2006; 51:1058-67. [PMID: 16901515 DOI: 10.1016/j.neuropharm.2006.06.014] [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] [Received: 12/07/2005] [Revised: 05/24/2006] [Accepted: 06/29/2006] [Indexed: 10/24/2022]
Abstract
CFM-2 [1-(4-aminophenyl)-3,5-dihydro-7,8-dimethoxy-4H-2,3-benzodiazepin-4-one] and THIQ-10c [N-acetyl-1-(4-chlorophenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline], are two non-competitive 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA) receptor antagonists, which demonstrated to antagonize generalized tonic-clonic seizures in different animal models. We have evaluated the effects of such compounds in a genetic animal model of absence epilepsy, the WAG/Rij rat. Animals were focally microinjected into specific brain areas of the cortico-thalamic circuit in order to evaluate the effects of these compounds on the number and duration of epileptic spike-wave discharges (SWDs) and better characterize the role of AMPA neurotransmission in this animal model. The focal microinjection of the two AMPA antagonists into some thalamic nuclei (ventralis posteromedialis (VPM), reticularis (NRT), ventralis posterolateralis (VPL) and the primary somatosensory forelimb region (S1FL)) was, generally, not able to significantly modify the occurrence of SWDs. Whereas, both compounds were able to reduce the number and duration of SWDs dose-dependently when microinjected into the peri-oral region of the primary somatosensory cortex (S1po). These findings suggest that AMPA receptor antagonists might play a role in absence epilepsies and that it might depend on the involvement of specific neuronal areas.
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Affiliation(s)
- Rita Citraro
- Section of Pharmacology, Department of Experimental and Clinical Medicine, Faculty of Medicine and Surgery, University of Catanzaro, School of Medicine at Catanzaro, Policlinico Mater Domini, Via Tommaso Campanella, 115, 88100 Catanzaro, Italy
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23
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van de Bovenkamp-Janssen MC, van der Kloet JC, van Luijtelaar G, Roubos EW. NMDA-NR1 and AMPA-GluR4 receptor subunit immunoreactivities in the absence epileptic WAG/Rij rat. Epilepsy Res 2006; 69:119-28. [PMID: 16487682 DOI: 10.1016/j.eplepsyres.2006.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 01/03/2006] [Accepted: 01/16/2006] [Indexed: 11/28/2022]
Abstract
From an age of 2-3 months onwards, the WAG/Rij rat, a genetic model for absence epilepsy, develops spike-wave discharges (SWD). SWD start in the peri-oral somatosensory cortex (POsc), whereas the rostral reticular thalamic nucleus (rRTN) contributes to synchronizing the thalamo-cortical oscillations. We hypothesize that N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoazolepropionic acid (AMPA) receptors in the POsc and rRTN are involved in, respectively, the initiation and synchronization of SWD activity. As a first step to test this hypothesis, 3 months old non-epileptic and 6 months old absence epileptic WAG/Rij rats were compared with age-matched non-epileptic ACI control rats. The presence of NMDA and AMPA receptors was assessed by quantifying immunostaining for the NMDA-NR1 subunit and the AMPA-GluR4 subunit, respectively. In the POsc, WAG/Rij rats of both ages showed less NMDA-NR1 (-14.7%) and AMPA-GluR4 (-8.7%) subunit staining than ACI rats. From 3 to 6 months, AMPA-GluR4 subunit staining more strongly increased in the rRTN of WAG/Rij rats than of ACI rats. Further studies should support our assumption that in the POsc of the WAG/Rij rat, SWD start as a result of reduced NMDA- and AMPA-mediated glutamatergic stimulation, and that AMPA-GluR4 containing neurons in the rRTN of this rat strain contribute to synchronization of thalamic and cortical neurons.
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Affiliation(s)
- Maartje C van de Bovenkamp-Janssen
- Department of Cellular Animal Physiology, Institute for Neuroscience, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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24
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Aker RG, Yananli HR, Gurbanova AA, Ozkaynakçi AE, Ateş N, van Luijtelaar G, Onat FY. Amygdala kindling in the WAG/Rij rat model of absence epilepsy. Epilepsia 2006; 47:33-40. [PMID: 16417529 DOI: 10.1111/j.1528-1167.2006.00367.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE The kindling model in rats with genetic absence epilepsy is suitable for studying mechanisms involved in the propagation and generalization of seizure activity in the convulsive and nonconvulsive components of epilepsy. In the present study, we compared the amygdala kindling rate and afterdischarge characteristics of the nonepileptic Wistar control rat with a well-validated model of absence epilepsy, the WAG/Rij rat, and demonstrated the effect of amygdala kindling on spike-and-wave discharges (SWDs) in the WAG/Rij group. METHODS Electrodes were stereotaxically implanted into the basolateral amygdala of rats for stimulation and recording and into the cortex for recording. After a recovery period, the animals were stimulated at their afterdischarge thresholds. EEG was recorded to analyze SWDs and afterdischarge durations. The seizure severity was evaluated by using Racine's 5-stage scale. RESULTS All nonepileptic control and four of seven WAG/Rij animals reached a stage 5 seizure state, whereas three animals failed to reach stage 3, 4, or 5 and stayed at stage 2 after application of 30 stimulations. Interestingly, WAG/Rij rats, resistant to kindling, demonstrated a significantly longer duration of SWDs on the first day of the experiment before kindling stimulation than did the kindled WAG/Rij animals. Additionally, the cumulative total duration and the number of SWDs after the kindling stimulation were statistically increased compared with SWDs before kindling stimulation. CONCLUSIONS The results of our study demonstrate that the progress of amygdala kindling is changed in rats with genetic absence epilepsy, perhaps as a consequence of the hundreds of daily SWDs.
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Affiliation(s)
- Rezzan Gülhan Aker
- Department of Pharmacology and Clinical Pharmacology, School of Medicine, Marmara University, Istanbul
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