1
|
Myren‐Svelstad S, Jamali A, Ophus SS, D'gama PP, Ostenrath AM, Mutlu AK, Hoffshagen HH, Hotz AL, Neuhauss SCF, Jurisch‐Yaksi N, Yaksi E. Elevated photic response is followed by a rapid decay and depressed state in ictogenic networks. Epilepsia 2022; 63:2543-2560. [PMID: 36222083 PMCID: PMC9804334 DOI: 10.1111/epi.17380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 07/27/2022] [Accepted: 07/27/2022] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The switch between nonseizure and seizure states involves profound alterations in network excitability and synchrony. In this study, we aimed to identify and compare features of neural excitability and dynamics across multiple zebrafish seizure and epilepsy models. METHODS Inspired by video-electroencephalographic recordings in patients, we developed a framework to study spontaneous and photically evoked neural and locomotor activity in zebrafish larvae, by combining high-throughput behavioral tracking and whole-brain in vivo two-photon calcium imaging. RESULTS Our setup allowed us to dissect behavioral and physiological features that are divergent or convergent across multiple models. We observed that spontaneous locomotor and neural activity exhibit great diversity across models. Nonetheless, during photic stimulation, hyperexcitability and rapid response dynamics were well conserved across multiple models, highlighting the reliability of photically evoked activity for high-throughput assays. Intriguingly, in several models, we observed that the initial elevated photic response is often followed by rapid decay of neural activity and a prominent depressed state. Elevated photic response and following depressed state in seizure-prone networks are significantly reduced by the antiseizure medication valproic acid. Finally, rapid decay and depression of neural activity following photic stimulation temporally overlap with slow recruitment of astroglial calcium signals that are enhanced in seizure-prone networks. SIGNIFICANCE We argue that fast decay of neural activity and depressed states following photic response are likely due to homeostatic mechanisms triggered by excessive neural activity. An improved understanding of the interplay between elevated and depressed excitability states might suggest tailored epilepsy therapies.
Collapse
Affiliation(s)
- Sverre Myren‐Svelstad
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neuromedicine and Movement Science, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neurology and Clinical NeurophysiologySt Olav's University HospitalTrondheimNorway
| | - Ahmed Jamali
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neuromedicine and Movement Science, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neurology and Clinical NeurophysiologySt Olav's University HospitalTrondheimNorway
| | - Sunniva S. Ophus
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Percival P. D'gama
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Anna M. Ostenrath
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Aytac Kadir Mutlu
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Helene Homme Hoffshagen
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Adriana L. Hotz
- Department of Molecular Life SciencesUniversity of ZürichZürichSwitzerland
| | | | - Nathalie Jurisch‐Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Department of Neurology and Clinical NeurophysiologySt Olav's University HospitalTrondheimNorway,Department of Clinical and Molecular Medicine, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Faculty of Medicine and Health SciencesNorwegian University of Science and TechnologyTrondheimNorway,Koç University Research Center for Translational Medicine, Department of NeurologyKoç University School of MedicineIstanbulTurkey
| |
Collapse
|
2
|
Italiano D, Striano P, Russo E, Leo A, Spina E, Zara F, Striano S, Gambardella A, Labate A, Gasparini S, Lamberti M, De Sarro G, Aguglia U, Ferlazzo E. Genetics of reflex seizures and epilepsies in humans and animals. Epilepsy Res 2016; 121:47-54. [PMID: 26875109 DOI: 10.1016/j.eplepsyres.2016.01.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/22/2016] [Accepted: 01/29/2016] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Reflex seizures are epileptic events triggered by specific motor, sensory or cognitive stimulation. This comprehensive narrative review focuses on the role of genetic determinants in humans and animal models of reflex seizures and epilepsies. METHODS References were mainly identified through MEDLINE searches until August 2015 and backtracking of references in pertinent studies. RESULTS Autosomal dominant inheritance with reduced penetrance was proven in several families with photosensitivity. Molecular genetic studies on EEG photoparoxysmal response identified putative loci on chromosomes 6, 7, 13 and 16 that seem to correlate with peculiar seizure phenotype. No specific mutation has been found in Papio papio baboon, although a genetic etiology is likely. Mutation in synaptic vesicle glycoprotein 2A was found in another animal model of photosensitivity (Fayoumi chickens). Autosomal dominant inheritance with incomplete penetrance overlapping with a genetic background for IGE was proposed for some families with primary reading epilepsy. Musicogenic seizures usually occur in patients with focal symptomatic or cryptogenic epilepsies, but they have been reported in rare genetic epilepsies such as Dravet syndrome. A single LGI1 mutation has been described in a girl with seizures evoked by auditory stimuli. Interestingly, heterozygous knockout (Lgi1(+/-)) mice show susceptibility to sound-triggered seizures. Moreover, in Frings and Black Swiss mice, the spontaneous mutations of MASS1 and JAMS1 genes, respectively, have been linked to audiogenic seizures. Eating seizures usually occur in symptomatic epilepsies but evidences for a genetic susceptibility were mainly provided by family report from Sri Lanka. Eating seizures were also reported in rare patients with MECP2 duplication or mutation. Hot water seizures are genetically heterogeneous but two loci at chromosomes 4 and 10 were identified in families with likely autosomal dominant inheritance. Startle-induced seizures usually occur in patients with symptomatic epilepsies but have also been reported in the setting chromosomal disorders or genetically inherited lysosomal storage diseases. DISCUSSION The genetic background of reflex seizures and epilepsies is heterogeneous and mostly unknown with no major gene identified in humans. The benefits offered by next-generation sequencing technologies should be merged with increasing information on animal models that represent an useful tool to study the mechanism underlying epileptogenesis. Finally, we expect that genetic studies will lead to a better understanding of the multiple factors involved in the pathophysiology of reflex seizures, and eventually to develop preventive strategies focused on seizure control and therapy optimization.
Collapse
Affiliation(s)
- Domenico Italiano
- Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 1, Messina, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
| | - Emilio Russo
- Science of Health Department, School of Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Antonio Leo
- Science of Health Department, School of Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 1, Messina, Italy
| | - Federico Zara
- Laboratory of Neurogenetics and Neurosciences, Department of Neurosciences, "G. Gaslini" Institute, Genova, Italy
| | - Salvatore Striano
- Epilepsy Center, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Antonio Gambardella
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy
| | - Angelo Labate
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy
| | - Sara Gasparini
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
| | - Marco Lamberti
- Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 1, Messina, Italy
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Umberto Aguglia
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy.
| | - Edoardo Ferlazzo
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
| |
Collapse
|
3
|
Abstract
ABSTRACT:Chickens homozygous for the epi gene (epileptics) suffer from spontaneous seizures throughout their life, whereas heterozygous (carriers) are phenotypically normal. Seizures can also be evoked in epileptics by photic stimulation. In addition, epileptic chickens' brains are 25% heavier than those of carriers. We have investigated whether hyperplasia or hypertrophy of astrocytes or increased numbers of astrocytic processes are involved in the development of seizures and the megalencephaly in this model by quantitative comparison of sections immunocytochemically stained for glial fibrillary acidic protein (GFAP). No statistically significant differences between epileptics and controls were found in any of seven areas selected for comparison. In this model gliosis is not involved in the development of epilepsy, nor does it result from repeated seizures.
Collapse
|
4
|
Douaud M, Feve K, Pituello F, Gourichon D, Boitard S, Leguern E, Coquerelle G, Vieaud A, Batini C, Naquet R, Vignal A, Tixier-Boichard M, Pitel F. Epilepsy caused by an abnormal alternative splicing with dosage effect of the SV2A gene in a chicken model. PLoS One 2011; 6:e26932. [PMID: 22046416 PMCID: PMC3203167 DOI: 10.1371/journal.pone.0026932] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 10/06/2011] [Indexed: 11/18/2022] Open
Abstract
Photosensitive reflex epilepsy is caused by the combination of an individual's enhanced sensitivity with relevant light stimuli, such as stroboscopic lights or video games. This is the most common reflex epilepsy in humans; it is characterized by the photoparoxysmal response, which is an abnormal electroencephalographic reaction, and seizures triggered by intermittent light stimulation. Here, by using genetic mapping, sequencing and functional analyses, we report that a mutation in the acceptor site of the second intron of SV2A (the gene encoding synaptic vesicle glycoprotein 2A) is causing photosensitive reflex epilepsy in a unique vertebrate model, the Fepi chicken strain, a spontaneous model where the neurological disorder is inherited as an autosomal recessive mutation. This mutation causes an aberrant splicing event and significantly reduces the level of SV2A mRNA in homozygous carriers. Levetiracetam, a second generation antiepileptic drug, is known to bind SV2A, and SV2A knock-out mice develop seizures soon after birth and usually die within three weeks. The Fepi chicken survives to adulthood and responds to levetiracetam, suggesting that the low-level expression of SV2A in these animals is sufficient to allow survival, but does not protect against seizures. Thus, the Fepi chicken model shows that the role of the SV2A pathway in the brain is conserved between birds and mammals, in spite of a large phylogenetic distance. The Fepi model appears particularly useful for further studies of physiopathology of reflex epilepsy, in comparison with induced models of epilepsy in rodents. Consequently, SV2A is a very attractive candidate gene for analysis in the context of both mono- and polygenic generalized epilepsies in humans.
Collapse
Affiliation(s)
- Marine Douaud
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | - Katia Feve
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | - Fabienne Pituello
- CNRS-Université Toulouse III, Centre de Biologie du Développement, Toulouse, France
| | - David Gourichon
- INRA PEAT, Pôle d'Expérimentation Avicole de Tours, Nouzilly, France
| | - Simon Boitard
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | - Eric Leguern
- INSERM, Neurogénétique Moléculaire et Cellulaire, Paris, France
| | - Gérard Coquerelle
- INRA, Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Agathe Vieaud
- INRA, Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Cesira Batini
- CNRS, Laboratoire de Génétique Moléculaire de la Neurotransmission et des Processus Neurodégénératifs, Paris, France
| | - Robert Naquet
- CNRS, Institut de Neurobiologie Alfred Fessard, Gif-sur-Yvette, France
| | - Alain Vignal
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | | | - Frédérique Pitel
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
- * E-mail:
| |
Collapse
|
5
|
Gong Z, Obenaus A, Li N, Sarty GE, Kendall EJ. Recurrent Nonstatus Generalized Seizures Alter the Developing Chicken Brain. Epilepsia 2003; 44:1380-7. [PMID: 14636344 DOI: 10.1046/j.1528-1157.2003.55902.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Noninvasive magnetic resonance imaging was used to assess the evolution of seizure-induced pathology in epileptic, carrier, and normal chickens. Our objective was to determine whether repetitively evoked seizures in an epileptic fowl model of generalized seizures resulted in altered brain development. METHODS Data were obtained from seizure and control groups at 45, 90, and 180 days after hatching. RESULTS At 180 days, apparent diffusion coefficient (ADC) values in the optic tectum and archistriatum of the stimulated epileptic chicks were reduced, whereas ADC values in the nonstimulated group remained unchanged. The mean brain volume of epileptic chickens from the stimulated group was smaller than that from the nonstimulated group at 90 and 180 days. CONCLUSIONS These findings establish that recurrent seizures modify the brain matrix.
Collapse
Affiliation(s)
- Zhao Gong
- Biomedical Engineering Division, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | | | | | | | | |
Collapse
|
6
|
Li N, Gong Z, Saucier D, Kendall EJ, Sarty GE. Water self-diffusion tensor changes in an avian genetic developmental model of epilepsy. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2003; 16:121-8. [PMID: 14523616 DOI: 10.1007/s10334-003-0020-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2002] [Accepted: 08/18/2003] [Indexed: 11/24/2022]
Abstract
Diffusion tensor imaging (DTI) was used to investigate whether tissue anisotropy in the developing brain is modified by recurrent seizures in epileptic chickens. Twelve epileptic chickens were sorted equally into two experimental groups at 10 days old. Until the age of 180 days, one group was photically stimulated beginning at an age of 2 weeks and repeated every 2 days while the other group was not stimulated. The photic stimulation induced generalized tonic-clonic seizures, and the unstimulated group did not display seizures. Both treatment groups were imaged at three time points, 45 (juvenile), 90 (adolescent), and 180 (adult) days posthatching, and maps of major and minor elements of anisotropy (eta and epsilon), trace and fractional anisotropy (FA) were generated. The eta, epsilon, and trace values in the hyperstriatum, archistriatum, and optic tectum showed significant changes as a function of developmental time point. Differences and/or interactions due to seizures were seen in the archistriatum and optic tectum for eta, epsilon, and trace with the largest differences between the stimulated and unstimulated birds being seen for eta in juvenile birds in the archistriatum (38.1 x 10(-11) m(2)/s versus 18.0 x 10(-11) m(2)/s) and the optic tectum (53.9 x 10(-11) m(2)/s versus 27.1 x 10(-11) m(2)/s). With the DTI parameters being sensitive to microstructure in the brain, these results demonstrate that seizures produce measurable differences, over unstimulated chickens, in brain structure for juvenile chickens, but the differences disappear as the brain matures. In other words, while seizure activity appears to induce atypical biophysical change (relative to unseizing birds) in the brain at a young age, the change is apparently reversed as the brain matures.
Collapse
Affiliation(s)
- Nan Li
- Division of Biomedical Engineering and Department of Medical Imaging, University of Saskatchewan, 9 Campus Drive, Saskatoon, Saskatchewan S7N 5A5, Canada
| | | | | | | | | |
Collapse
|
7
|
Yasuda S, Ishida N, Higashiyama A, Morinobu S, Kato N. Characterization of audiogenic-like seizures in naive rats evoked by activation of AMPA and NMDA receptors in the inferior colliculus. Exp Neurol 2000; 164:396-406. [PMID: 10915578 DOI: 10.1006/exnr.2000.7401] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of glutamate receptors in the inferior colliculus (IC) in audiogenic and audiogenic-like seizures was investigated in adult rats with transient neonatal hypothyroidism by 0.02% propylthiouracil (PTU) treatment through mother's milk (PTU rats) and in naive rats treated intracisternally with N-methyl-d-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazole-proprionic acid (AMPA), or cyclothiazide, an inhibitor of rapid AMPA receptor desensitization. All rats showed audiogenic or audiogenic-like seizures characterized by running fit (RF) and generalized tonic-clonic seizures (GTCS). While systemically administered MK-801 inhibited GTCS, intracisternally administered NBQX inhibited RF and GTCS in both audiogenic and audiogenic-like seizures. Auditory stimulation shortened the latency to GTCS induced by AMPA, but not NMDA, at a subclinical dose and further elongated the shortened duration of RF, but not GTCS, induced by MK-801 pretreatment. Furthermore, Northern blot analysis was used to evaluate the expression of the immediate-early gene c-fos in the IC following induction of audiogenic or audiogenic-like seizures. The significant induction of c-fos mRNA by audiogenic seizures in PTU rats or by AMPA- or cyclothiazide-induced seizures in naive rats was prominent in the IC. MK-801 suppressed c-fos mRNA expression in the IC induced by audiogenic seizures in PTU rats or by AMPA-induced seizures in naive rats. NBQX suppressed the expression of c-fos mRNA in the IC induced by AMPA-induced seizures but did not suppress c-fos mRNA in PTU rats or rats with cyclothiazide-induced seizures. Auditory stimuli failed to affect c-fos mRNA induction by AMPA. The present study suggests that audiogenic-like seizures can be reproduced by glutamate receptor agonists in which AMPA receptors are primarily linked to the initiation of audiogenic seizures (RF) while NMDA receptors presumably located within the IC are involved in the propagation of GTCS in audiogenic seizures.
Collapse
Affiliation(s)
- S Yasuda
- Department of Psychiatry, Shiga University of Medical Science, Setatsukinowa-cho, Otsu, 520-2192, Japan
| | | | | | | | | |
Collapse
|
8
|
Le Douarin NM, Catala M, Batini C. Embryonic neural chimeras in the study of vertebrate brain and head development. INTERNATIONAL REVIEW OF CYTOLOGY 1997; 175:241-309. [PMID: 9203359 DOI: 10.1016/s0074-7696(08)62128-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Construction of neural chimeras between quail and chick embryos has been employed since 1969 when the unique nucleolar structure of the quail nucleus and its use to devise a cell marking technique by associating quail and chick cells in ovo were described in the "Bulletin Biologique de la France et de la Belgique." This method was first applied to the ontogeny of the neural crest, a structure whose development involves extensive cell migration, and, since 1984, to that of the central nervous system (CNS). This chapter highlights some of the most significant findings provided by this approach concerning the CNS, such as (i) demonstration of the common origin of the floor plate and notochord from a group of cells localized in the "organizer", i.e., Hensen's node, and the way in which these two structures become positioned respectively within and under the neural tube during gastrulation and neurulation in Amniotes; (ii) the neural crest origin of the skull vault and the facial and hypobranchial skeleton. This means that the mesodermal contribution to the skull is limited to the occipital and otic regions and extends only to the rostral limit of the notochord. A correlation can be drawn between the development of the telencephalon and the mesectodermally derived skull in the vertebrate phylum; (iii) demonstration that the midbrain-hindbrain junction, at the stage of the encephalic vesicles, acts as an organizing center for tectal and cerebellar structures. This function was correlated with the activity of several developmental genes, thus providing insight into their function during neurogenesis; (iv) the pattern of morphogenetic movements and cell migration taking place in defined brain-to-be areas, as well as the origin of various cell types of nervous tissues; and (v) a new avenue for studying brain localization of either behavioral traits or genetically encoded brain disorders.
Collapse
Affiliation(s)
- N M Le Douarin
- Institut d'Embryologie Cellulaire et Moléculaire du CNRS, Nogent-sur-Marne, France
| | | | | |
Collapse
|
9
|
Batini C, Teillet MA, Naquet R, Le Douarin NM. Brain chimeras in birds: application to the study of a genetic form of reflex epilepsy. Trends Neurosci 1996; 19:246-52. [PMID: 8761961 DOI: 10.1016/0166-2236(96)10026-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A strain of chicken, called here FEpi (for Fayoumi epileptic), bearing an autosomal recessive mutation, exhibits a form of reflex epilepsy with EEG interictal paroxysmal manifestations and generalized seizures in response to either light or sound stimulations. By using the brain chimera technology, we demonstrate here that the epileptic phenotype can be partially or totally transferred from an FEpi to a normal chick by grafting specific regions of the embryonic brain. The mesencephalon contains the generator of all epileptic manifestations whether they involve visual or auditory neuronal circuits, with the exception of the abnormal EEG which is transmitted exclusively by telencephalic grafts. This analysis supports the hypothesis that certain forms of human and mammalian epilepsies have a brainstem origin.
Collapse
Affiliation(s)
- C Batini
- Laboratoire de Physiologie de la Motricité, CNRS, Université Pierre-et-Marie Curie, CHU Pitié-Salpêtrière, Paris, France
| | | | | | | |
Collapse
|
10
|
Abstract
The cause of learning impairment in children with seizure disorders is obscure, in part because of the lack of adequate animal models of learning deficiencies that can be used for study. The discriminating passive avoidance test has been used extensively to study learning behavior in chicks. In the present study, we applied the passive avoidance test to epileptic chicks to determine if learning deficiencies could be demonstrated in this epileptic model. Epileptic fowl have a hereditary form of primary generalized epilepsy characterized by tonic-clonic seizures. The seizures occur spontaneously and can also be induced by photic stimulation. The epileptic phenotype is the result of an autosomal recessive mutation. Heterozygotes do not have seizures and were used as age-matched controls. The discriminating passive avoidance test used in the present study was based on the observation that chicks readily peck at bright shiny beads. Once chicks taste a colored bead coated with a bitter chemical (methylanthranilate), they refuse to peck the bead on subsequent presentations. In addition, chicks can discriminate between colored beads and will continue to peck at a bead of different color than the methylanthranilate (MeA)-coated bead. compared to carriers, epileptic chicks demonstrated significantly less ability to discriminate between colored beads. Furthermore, this learning impairment was observed in epileptic chicks treated with phenobarbital (PB), indicating that the learning impairment in epileptic chicks is an inherent neurological problem and not a consequence of seizure activity.
Collapse
Affiliation(s)
- D D Gervais-Fagnou
- Department of Pharmacology, University of Saskatchewan, Saskatoon, Canada
| | | |
Collapse
|
11
|
Fadlallah N, Guy N, Teillet MA, Schuler B, Le Douarin NM, Naquet R, Batini C. Brain chimeras for the study of an avian model of genetic epilepsy: structures involved in sound and light-induced seizures. Brain Res 1995; 675:55-66. [PMID: 7796153 DOI: 10.1016/0006-8993(95)00038-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The epileptic homozygotes of the Fayoumi strain of chickens (Fepi) are affected by photogenic reflex epilepsy with complete penetrance. Here we demonstrate that they are equally affected by audiogenic reflex epilepsy induced by intense sound stimulation. All the Fepi display sound-induced seizures from hatching to adulthood consisting of initial 'ictal arousal' and running fits usually followed by generalized clonico-tonic convulsions. A running fit is the preconvulsive motor symptom specifically induced by auditory stimulation while neck myoclonus is the preconvulsive motor symptom specifically induced by photic stimulation. The EEG interictal spikes and spike and waves are suppressed and replaced by a desynchronized trace during the seizures of both kinds. Viable neural chimeras were obtained by graft of embryonic brain vesicles from Fepi donors into normal chick embryos. Transfer of the complete audiogenic and photogenic phenotypes was obtained in chimeras resulting from embryonic substitution of both the prosencephalon and mesencephalon. The substitution of the prosencephalon alone resulted in transfer of interictal paroxysmal EEG activity accompanied by the sound and light-induced desynchronization and 'ictal arousal' with no motor seizures. Chimeras with embryonic substitution of the mesencephalon alone displayed running fits and convulsions induced by sound stimulation but only neck myoclonus following light stimulation. The conclusions are reached that: (i) the Fepi is a model of audiogenic and photogenic reflex epilepsy; (ii) in both types, the seizure initiator and the convulsion generator are localized in the brainstem, although reinforcement from telencephalic visual structures is needed to trigger photogenic generalized convulsions.
Collapse
Affiliation(s)
- N Fadlallah
- Laboratoire de Physiologie de la Motricité, CNRS et Université Pierre et Marie Curie, Paris, France
| | | | | | | | | | | | | |
Collapse
|
12
|
Teillet MA, Guy N, Fadlallah N, Le Gal La Salle G, Schuler B, Batini C, Le Douarin N, Naquet R. Reflex epilepsy of the fowl and its transfer to normal chickens by brain embryonic grafts. ITALIAN JOURNAL OF NEUROLOGICAL SCIENCES 1995; 16:83-89. [PMID: 7642357 DOI: 10.1007/bf02229079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The genetic photosensitive epilepsy of the Fayoumi chicken was transferred to normal chickens by in situ grafts at 2 days of incubation, of both the prosencephalic and mesencephalic brain vesicles taken from epileptic embryos. However, mesencephalic graft is sufficient to allow convulsions under sound stimulation. Typical EEG patterns are recorded in chimeras having the prosencephalon plus or not the mesencephalon. We conclude that, in this mutant, the whole neural tissue is affected, but the seizure generator is localized inside the mesencephalon, and specific sensory pathways are necessary for seizures to occur.
Collapse
Affiliation(s)
- M A Teillet
- Institut d'Embryologie Cellulaire et Moléculaire, CNRS-UMRC 9924, Nogent/Marne, France
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Guy NT, Fadlallah N, Naquet R, Batini C. Development of epileptic activity in embryos and newly hatched chicks of the Fayoumi mutant chicken. Epilepsia 1995; 36:101-7. [PMID: 8001501 DOI: 10.1111/j.1528-1157.1995.tb01673.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The homozygous Fayoumi strain of epileptic chickens (Fepi) is affected by generalized convulsions consistently induced by intermittent light stimulation (ILS) and by intense sound. Although interictal EEG recordings show continuous spikes and spike and wave activity, desynchronization and flattening (DF) of the EEG are observed during seizures. We have studied development of the epileptic phenotype in embryonic (E) and posthatching (P) Fepi. As compared with those of chicken embryos of a normal strain, no differences were observed in the EEG before embryonic day (E) 16. Clearly differentiated spikes and spike and waves appeared at E17 in Fepi. Metrazol-induced EEG seizures were observed at E16 in normal embryos and at E17 in Fepi. The Fepi showed some characteristics: Spontaneous EEG seizure-like discharges also appeared at E17 but decreased toward hatching; visual or acoustic hyperexcitability developed at E20 together with evoked responses in normal chickens; desynchronization of the EEG, typical of the epileptic seizure of the adult, could be induced by ILS at B20, but ILS- or sound-induced generalized motor seizures appeared at P1, a few hours after hatching. Results show that Fepi phenotype reaches full expression at P1, but the electric paroxysms are expressed earlier, paralleling synaptic maturation.
Collapse
Affiliation(s)
- N T Guy
- Laboratoire de Physiologie de la Motricité, CNRS-UR 14, Université Pierre et Marie Curie, CHU Pitié-Salpetrière, Paris, France
| | | | | | | |
Collapse
|
14
|
Guy N, Teillet MA, Schuler B, Le Gal la Salle G, Le Douarin N, Naquet R, Batini C. Pattern of electroencephalographic activity during light induced seizures in genetic epileptic chicken and brain chimeras. Neurosci Lett 1992; 145:55-8. [PMID: 1461568 DOI: 10.1016/0304-3940(92)90202-i] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Genetic epilepsy was studied in Fayoumi epileptic (F.Epi) chickens and in neural chimeras obtained by selective substitution of embryonic brain vesicles of F.Epi donors in normal recipient chickens. Typical motor seizures accompanied by convulsions were evoked by intermittent light stimulation in F.Epi and in chimeras having embryonic substitution of the prosencephalon and the mesencephalon. The motor seizure was less severe in chimeras receiving only the prosencephalon. In the F.Epi, as well as in all the chimeras, the EEG during seizures was characterized by a desynchronized (or a flattening) pattern of activity. F.Epi and chimeras had a lower threshold to Metrazol induced seizures than control chickens. The experimental animals show that, in this model, large prosencephalic and mesencephalic areas are involved in the epileptic disease. The epileptic character of this genetic dysfunction is discussed.
Collapse
Affiliation(s)
- N Guy
- Laboratoire de Physiologie de la Motricité, CNRS-URA 385, Paris, France
| | | | | | | | | | | | | |
Collapse
|
15
|
Teillet MA, Naquet R, Le Gal La Salle G, Merat P, Schuler B, Le Douarin NM. Transfer of genetic epilepsy by embryonic brain grafts in the chicken. Proc Natl Acad Sci U S A 1991; 88:6966-70. [PMID: 1871111 PMCID: PMC52214 DOI: 10.1073/pnas.88.16.6966] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In the Fayoumi chicken, a spontaneous recessive autosomal mutation (F.Epi) is responsible for high susceptibility to seizures that are especially inducible by intermittent light stimulation. Substitution of defined areas of the encephalic neuroepithelium in normal chicken embryos at 2 days of incubation by their counterparts from homozygous F.Epi embryos generates the epileptic phenotype in the chimeras. It was found that grafting primordia of both prosencephalon and mesencephalon of homozygous F.Epi birds is necessary and sufficient for transfer of the full disease. When grafted alone, the homozygous F.Epi prosencephalon, although showing the typical epileptic interictal electroencephalogram, does not allow the complete epileptic seizures to occur in the hosts. Grafts of mesencephalon and/or rhombencephalon modify neither the behavior nor the electroencephalographic pattern of the recipient chickens. Cooperation of forebrain and midbrain activities is therefore required to yield epileptic seizures in this model.
Collapse
Affiliation(s)
- M A Teillet
- Institut d'Embryologie Cellulaire et Moléculaire du Centre National de la Recherche Scientifique et du Collège de France, Nogent-sur-Marne
| | | | | | | | | | | |
Collapse
|
16
|
Pedder SC, Wilcox RI, Tuchek JM, Johnson DD, Crawford RD. Quisqualate receptors in epileptic fowl: the absence of coupling between quisqualate and N-methyl-D-aspartate receptors. Eur J Pharmacol 1990; 175:85-91. [PMID: 2157599 DOI: 10.1016/0014-2999(90)90156-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The ability of excitatory amino acid receptor agonists, AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and quisqualate to produce seizures was determined in 1-2 day old epileptic and non-epileptic (carrier) chicks. Both compounds produced prolonged clonic seizures in epileptic chicks at doses which were not convulsant in carrier chicks. Seizures produced in epileptics by AMPA were suppressed by the quisqualate antagonist CNQX (6-cyano-7-nitroquinoxaline-2,3-dione), but were not prevented by pretreatment with competitive (2-amino-7-phosphonoheptanoic acid, APH) or non-competitive (MK-801) NMDA (N-methyl-D-aspartate) receptor antagonists. These data do not support the hypothesis that NMDA receptors work in concert with quisqualate receptors. Binding sites for [3H]AMPA were characterized in cerebral hemispheres of both epileptic and carrier chicks. Analysis of the data revealed no significant alterations in the binding affinity (KD) or the number of binding sites (Bmax) of AMPA to tissue preparations from epileptic chickens when compared to carriers. The latter data does not explain the increased susceptibility of epileptic fowl to the convulsant effects of quisqualate and AMPA.
Collapse
Affiliation(s)
- S C Pedder
- Department of Pharmacology, University of Saskatchewan, Saskatoon, Canada
| | | | | | | | | |
Collapse
|
17
|
George DH, Munoz DG, McConnell T, Crawford RD. Megalencephaly in the epileptic chicken: a morphometric study of the adult brain. Neuroscience 1990; 39:471-7. [PMID: 2087267 DOI: 10.1016/0306-4522(90)90283-a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The epileptic chicken is a genetic model of generalized epilepsy in which epilepsy is combined with megalencephaly. We have performed a morphometric study of the brains of adult epileptic hens, using heterozygous carrier hens as controls. There is no obvious disorder of cell form or of architectural arrangement in the megalencephalic brains. We have found that the enlargement of the epileptic brain is not uniform: it is most marked in the telencephalon, and is present to a lesser degree in the cerebellum, but neither the optic tectum nor the diencephalic nucleus rotundus shows a significant increase in size. The enlarged regions are characterized by a decrease in the packing density of neurons. There is an increase in the total neuron population in some of the enlarged areas (archistriatum), despite the lower density per unit volume, but in other enlarged areas (hippocampus) there is no difference in total neuron numbers. The glial cells, by contrast, show no significant alteration in packing density. These findings suggest that the megalencephaly of the epileptic chicken is due to an increase in neuron size, with a contribution from increased numbers of neurons and glial cells. The epileptic chicken may provide a valuable model for further dynamic studies of aberrant neuronal development, and of structural-functional relationships in epilepsy.
Collapse
Affiliation(s)
- D H George
- Department of Pathology, University of Western Ontario, Ontario, Canada
| | | | | | | |
Collapse
|
18
|
Pedder SC, Wilcox R, Tuchek JM, Johnson DD, Crawford RD. The relationship between anticonvulsant activity and receptor affinity of N-methyl-D-aspartate antagonists in epileptic fowl. Neuropharmacology 1989; 28:753-6. [PMID: 2548114 DOI: 10.1016/0028-3908(89)90162-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The N-methyl-D-aspartate (NMDA) receptor antagonists [(3-(+/-)2-carboxypiperazin-4-yl)-propyl-l-phosphonic acid (CPP), +/- 2-amino-7-phosphonoheptanoic acid (2AP7), +/- 2-amino-5-phosphonovaleric acid (2AP5), D-alpha-aminoadipic acid (alpha AA), and +/- alpha, epsilon-diaminopimelic acid (DAP)] were tested for anticonvulsant activity in epileptic chickens. There was a high correlation between anticonvulsant potencies (ED50) and the affinity for the NMDA receptor measured by displacement of L-[3H]glutamate from synaptosomal membranes. The high seizure susceptibility is not due to abnormalities in the NMDA receptor as comparison of KD, Bmax and Ki values in synaptosomal preparations from epileptic and non-epileptic chickens indicated no differences in NMDA receptor binding receptor characteristics.
Collapse
Affiliation(s)
- S C Pedder
- Department of Pharmacology College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | | | | | | | | |
Collapse
|
19
|
Abstract
The El mouse is a model of hereditary sensory precipitated temporal lobe epilepsy. All adult El mice given rhythmic vestibular stimulation (e.g. tossing, rocking) during development will experience tonic-clonic convulsions when given similar stimulation as adults. The seizures have prodromal, convulsive, and postictal stages. EEG and 2-deoxyglucose studies have localized the seizures to the temporal lobe, with onset in the hippocampus. El mice have a decreased threshold for convulsion by electrical or pharmacologic stimulation. A variety of anticonvulsant medications eliminate El mouse seizures, including phenytoin (PHT), phenobarbital (PB), valproate (VPA), and ethosuximide (ESM). Anatomic studies have shown subtle differences in the thalamus and hippocampus of El mice. Immunohistochemistry of the El mouse hippocampus has revealed changes in peptidergic and gabaergic cell populations. Numerous biochemical differences have been found between El and nonconvulsive mice, including increased acetylcholine (ACh), dopamine (DA), GABA, serotonin (5-HT), and decreased norepinephrine (NE).
Collapse
Affiliation(s)
- J T King
- Section of Neurological Surgery, Yale University School of Medicine, New Haven, Connecticut 06510
| | | |
Collapse
|
20
|
Pedder SC, Wilcox R, Tuchek J, Johnson DD, Crawford RD. Protection by GABA agonists, gamma-hydroxybutyric acid, and valproic acid against seizures evoked in epileptic chicks by hyperthermia. Epilepsia 1988; 29:738-42. [PMID: 3142760 DOI: 10.1111/j.1528-1157.1988.tb04228.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
With microwave diathermy, febrile seizures were produced in epileptic chicks aged 2-5 days. Drugs that enhance GABAergic activity (i.e., GABA, muscimol, and progabide), as well as valproic acid and gamma-hydroxybutyric acid, produced dose-dependent increases in latency to onset of seizures.
Collapse
Affiliation(s)
- S C Pedder
- Department of Pharmacology, University of Saskatchewan, Saskatoon, Canada
| | | | | | | | | |
Collapse
|
21
|
Pedder SC, Wilcox R, Tuchek JM, Crawford RD, Johnson DD. Benzodiazepine antagonist Ro 15-1788 (flumazepil) attenuates the anticonvulsant activity of diazepam in epileptic fowl. Brain Res 1987; 424:139-43. [PMID: 3121132 DOI: 10.1016/0006-8993(87)91203-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ability of the imidazobenzodiazepine Ro 15-1788 to displace diazepam from brain membranes in vitro and to antagonize the anticonvulsant activity of diazepam in vivo was determined in epileptic fowl. At doses of 1.0 mg/kg and higher, Ro 15-1788 significantly attenuated the anticonvulsant action of diazepam (1.0 mg/kg) in epileptic chickens. Ro 15-1788 alone exerted no anticonvulsant activity even in doses as high as 10 mg/kg. Specific binding of 10 nM [3H]diazepam to whole homogenate fractions prepared from cerebral hemispheres of epileptic fowl was inhibited by Ro 15-1788 with an IC50 of 8.5 nM and the Ki was determined to be 4.25 nM. These results suggest that Ro 15-1788 competes directly with diazepam for a binding site involved in producing anticonvulsant activity.
Collapse
Affiliation(s)
- S C Pedder
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | | | | | | | | |
Collapse
|
22
|
Gregory NG, Wotton SB. Effect of electrical stunning on the electroencephalogram in chickens. THE BRITISH VETERINARY JOURNAL 1987; 143:175-83. [PMID: 3580824 DOI: 10.1016/0007-1935(87)90009-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
23
|
Johnson DD, Wilcox R, Tuchek JM, Crawford RD. Experimental febrile convulsions in epileptic chickens: the anticonvulsant effect of elevated gamma-aminobutyric acid concentrations. Epilepsia 1985; 26:466-71. [PMID: 4043016 DOI: 10.1111/j.1528-1157.1985.tb05682.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The high seizure susceptibility in epileptic chickens is due to an autosomal recessive mutation. In 3-day-old chicks homozygous for the epilepsy gene (epileptics), elevation of body temperature using microwave diathermy evoked an initial febrile seizure resembling the clonic seizures evoked in epileptic chicks by photic stimulation. After complete recovery, this was followed by a clonic-tonic seizure. In nonepileptic heterozygote hatchmates (carriers) of the same age, only the latter seizure pattern was observed. In 16- to 17-day-old chicks of either phenotype, both seizure patterns were observed during hyperthermia. In all cases, the temperature at which seizures occurred was significantly lower in epileptic than in nonepileptic chicks, indicating a lower threshold for febrile seizures when there is an inherited predisposition to convulse. The occurrence of seizures was dependent on the body temperature and not on the rate of rise of temperature. Elevation of the brain gamma-aminobutyric acid (GABA) concentrations by administration of the GABA transaminase inhibitor gamma-vinyl GABA reduced the incidence of the initial febrile seizures and increased the latency in those birds that were not fully protected.
Collapse
|
24
|
Johnson DD, Fisher TE, Tuchek JM, Crawford RD. Pharmacology of methyl- and propyl-beta-carbolines in a hereditary model of epilepsy. Neuropharmacology 1984; 23:1015-7. [PMID: 6151141 DOI: 10.1016/0028-3908(84)90122-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Intravenous administration of beta-carboline-3-carboxylate methyl ester (beta-CCM) produced convulsions at small doses (0.03 mg/kg) in adult chickens, homozygous for the epileptic gene. Nonepileptic heterozygote hatchmates (carriers) did not undergo seizures at doses of 1 mg/kg, and doses of 3-5 mg/kg produced only brief myoclonic responses. The convulsant effect of beta-CCM could be prevented by pretreatment with large doses of beta-carboline-3-carboxylate propyl ester (beta-CCP). beta-Carboline-3-carboxylate methyl ester displayed a higher affinity than diazepam in displacement studies on synaptosomal membrane preparations from brains of epileptic and carrier chickens.
Collapse
|
25
|
Crawford KD, Johnson DD, Hickie RA, Crawford RD. Cyclic nucleotides and seizures in a hereditary model of epilepsy. Brain Res Bull 1984; 12:137-42. [PMID: 6324961 DOI: 10.1016/0361-9230(84)90226-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The high seizure susceptibility in epileptic fowl is due to an autosomal recessive mutation. Cyclic AMP and cyclic GMP concentrations were determined in brains from two day old epileptic chicks (homozygotes) during an inter-ictal period as well as during and following a seizure evoked by stroboscopic stimulation. The data were compared to values obtained from non-epileptic carrier chicks (heterozygotes) sacrificed in an unstimulated state or subjected to the seizure evoking stimulus. During the inter-ictal state in epileptics no abnormalities were found in cyclic nucleotide concentrations indicating that the high seizure susceptibility is not related to abnormalities of these nucleotides. Although seizure activity in epileptics was associated with reduced cyclic AMP in the optic lobes this also occurred in carrier chicks subjected to the seizure evoking stimulus. The only significant changes in cyclic GMP levels, occurring as a result of seizures in epileptics, were an increase in cyclic GMP in the cerebral hemispheres during the seizure and a decrease in the optic lobes during the postictal period.
Collapse
|
26
|
Johnson DD, Crawford KD, Crawford RD. Febrile seizures in epileptic chicks: the effects of phenobarbital, phenytoin and valproate. Can J Neurol Sci 1983; 10:96-9. [PMID: 6407741 DOI: 10.1017/s0317167100044711] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Epileptic seizures can be evoked in chicks homozygous for the epileptic seizure gene (epi, epi) by elevating their body temperature using microwave diathermy. These seizures precede and differ in motor seizure pattern from a second clonic-tonic seizure produced by hyperthermia in both epileptic and carrier (heterozygote, Epi, epi) chicks. Hyperthermia did not evoke seizures in adult epileptic chickens. Phenobarbital delayed the onset of epileptiform seizures whereas phenytoin and valproate had no effect. These data suggest that epileptic chicks may provide a suitable model for studies on febrile convulsions.
Collapse
|
27
|
Wood JD, Johnson DD, Krogsgaard-Larsen P, Schousboe A. Anticonvulsant activity of the glial-selective GABA uptake inhibitor, THPO. Neuropharmacology 1983; 22:139-42. [PMID: 6843784 DOI: 10.1016/0028-3908(83)90275-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The intramuscular administration of 4,5,6,7-tetrahydroisoxazolo [4,5-c] pyridin-3-ol (THPO) delayed the onset of isonicotinic acid hydrazide-induced seizures in very young chicks but not in adult mice, the difference being due to the state of development of the blood-brain-barrier which controls access of the drug to the brain tissue. THPO was also effective in preventing seizures induced in epileptic chicks by intermittent photic stimulation. The anticonvulsant action after combined administration of THPO and gabaculine, an inhibitor of GABA-alpha-oxoglutarate aminotransferase activity, was no greater than the anticonvulsant action of gabaculine alone.
Collapse
|
28
|
Suzuki J, Nakamoto Y. Seizure patterns and electroencephalograms of E1 mouse. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1977; 43:299-311. [PMID: 70331 DOI: 10.1016/0013-4694(77)90253-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
29
|
Suzuki J. Paroxysmal discharges in the electroencephalogram of the E1 mouse. EXPERIENTIA 1976; 32:336-8. [PMID: 1253902 DOI: 10.1007/bf01940824] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|