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Keller D, Erö C, Markram H. Cell Densities in the Mouse Brain: A Systematic Review. Front Neuroanat 2018; 12:83. [PMID: 30405363 PMCID: PMC6205984 DOI: 10.3389/fnana.2018.00083] [Citation(s) in RCA: 210] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/20/2018] [Indexed: 11/29/2022] Open
Abstract
The mouse brain is the most extensively studied brain of all species. We performed an exhaustive review of the literature to establish our current state of knowledge on cell numbers in mouse brain regions, arguably the most fundamental property to measure when attempting to understand a brain. The synthesized information, collected in one place, can be used by both theorists and experimentalists. Although for commonly-studied regions cell densities could be obtained for principal cell types, overall we know very little about how many cells are present in most brain regions and even less about cell-type specific densities. There is also substantial variation in cell density values obtained from different sources. This suggests that we need a new approach to obtain cell density datasets for the mouse brain.
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Affiliation(s)
- Daniel Keller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
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2
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Farrar MJ, Kolkman KE, Fetcho JR. Features of the structure, development, and activity of the zebrafish noradrenergic system explored in new CRISPR transgenic lines. J Comp Neurol 2018; 526:2493-2508. [PMID: 30070695 DOI: 10.1002/cne.24508] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/24/2018] [Accepted: 07/29/2018] [Indexed: 11/11/2022]
Abstract
The noradrenergic (NA) system of vertebrates is implicated in learning, memory, arousal, and neuroinflammatory responses, but is difficult to access experimentally. Small and optically transparent, larval zebrafish offer the prospect of exploration of NA structure and function in an intact animal. We made multiple transgenic zebrafish lines using the CRISPR/Cas9 system to insert fluorescent reporters upstream of slc6a2, the norepinephrine transporter gene. These lines faithfully express reporters in NA cell populations, including the locus coeruleus (LC), which contains only about 14 total neurons. We used the lines in combination with two-photon microscopy to explore the structure and projections of the NA system in the context of the columnar organization of cell types in the zebrafish hindbrain. We found robust alignment of NA projections with glutamatergic neurotransmitter stripes in some hindbrain segments, suggesting orderly relations to neuronal cell types early in life. We also quantified neurite density in the rostral spinal cord in individual larvae with as much as 100% difference in the number of LC neurons, and found no correlation between neuronal number in the LC and projection density in the rostral spinal cord. Finally, using light sheet microscopy, we performed bilateral calcium imaging of the entire LC. We found that large-amplitude calcium responses were evident in all LC neurons and showed bilateral synchrony, whereas small-amplitude events were more likely to show interhemispheric asynchrony, supporting the potential for targeted LC neuromodulation. Our observations and new transgenic lines set the stage for a deeper understanding of the NA system.
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Affiliation(s)
- Matthew J Farrar
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York.,Department of Math, Physics and Statistics, Messiah College, Mechanicsburg, Pennsylvania
| | - Kristine E Kolkman
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York
| | - Joseph R Fetcho
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York
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3
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Aumann T, Horne M. Activity‐dependent regulation of the dopamine phenotype in substantia nigra neurons. J Neurochem 2012; 121:497-515. [DOI: 10.1111/j.1471-4159.2012.07703.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Tim Aumann
- Florey Neuroscience Institutes, Melbourne Brain Centre, The University of Melbourne, Parkville, Victoria, Australia
- Centre for Neuroscience, Melbourne Brain Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Mal Horne
- Florey Neuroscience Institutes, Melbourne Brain Centre, The University of Melbourne, Parkville, Victoria, Australia
- St Vincent’s Hospital, Fitzroy, Victoria, Australia
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4
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A method for modeling and visualizing the three-dimensional organization of neuron populations from replicated data: Properties, implementation and illustration. Pattern Recognit Lett 2011. [DOI: 10.1016/j.patrec.2011.07.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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5
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Herculano-Houzel S. Coordinated scaling of cortical and cerebellar numbers of neurons. Front Neuroanat 2010; 4:12. [PMID: 20300467 PMCID: PMC2839851 DOI: 10.3389/fnana.2010.00012] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 02/18/2010] [Indexed: 11/13/2022] Open
Abstract
While larger brains possess concertedly larger cerebral cortices and cerebella, the relative size of the cerebral cortex increases with brain size, but relative cerebellar size does not. In the absence of data on numbers of neurons in these structures, this discrepancy has been used to dispute the hypothesis that the cerebral cortex and cerebellum function and have evolved in concert and to support a trend towards neocorticalization in evolution. However, the rationale for interpreting changes in absolute and relative size of the cerebral cortex and cerebellum relies on the assumption that they reflect absolute and relative numbers of neurons in these structures across all species - an assumption that our recent studies have shown to be flawed. Here I show for the first time that the numbers of neurons in the cerebral cortex and cerebellum are directly correlated across 19 mammalian species of four different orders, including humans, and increase concertedly in a similar fashion both within and across the orders Eulipotyphla (Insectivora), Rodentia, Scandentia and Primata, such that on average a ratio of 3.6 neurons in the cerebellum to every neuron in the cerebral cortex is maintained across species. This coordinated scaling of cortical and cerebellar numbers of neurons provides direct evidence in favor of concerted function, scaling and evolution of these brain structures, and suggests that the common notion that equates cognitive advancement with neocortical expansion should be revisited to consider in its stead the coordinated scaling of neocortex and cerebellum as a functional ensemble.
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Affiliation(s)
- Suzana Herculano-Houzel
- Laboratório de Neuroanatomia Comparada, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro Rio de Janeiro-RJ, Brazil
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6
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Burguet J, Andrey P, Rampin O, Maurin Y. Three-dimensional statistical modeling of neuronal populations: illustration with spatial localization of supernumerary neurons in the locus coeruleus of quaking mutant mice. J Comp Neurol 2009; 513:483-95. [PMID: 19226531 DOI: 10.1002/cne.21954] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An algorithm for the three-dimensional statistical representation of neuronal populations was designed and implemented. Using this algorithm a series of 3D models, calculated from repeated histological experiments, can be combined to provide a synthetic vision of a population of neurons taking into account biological and experimental variability. Based on the point process theory, our algorithm allows computation of neuronal density maps from which isodensity surfaces can be readily extracted and visualized as surface models revealing the statistical organization of the neuronal population under study. This algorithm was applied to the spatial distribution of locus coeruleus (LC) neurons of 30- and 90-day-old control and quaking mice. By combining 12 3D models of the LC, a region of the nucleus in which a subpopulation of neurons loses its noradrenergic phenotype between 30 and 90 days postnatally was demonstrated in control mice but not in quaking mice, leading to the hyperplasia previously reported in adult mutants. Altogether, this algorithm allows computation of 3D statistical and graphical models of neuronal populations, providing a contribution to quantitative 3D neuroanatomical modeling.
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Affiliation(s)
- Jasmine Burguet
- Equipe Analyse & modélisation en imagerie biologique, Nopa, Umr 1197 Inra-Université Paris 11, bât 325, Jouy-en-Josas 78352, France.
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7
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McInnes LA, Lauriat TL. RNA metabolism and dysmyelination in schizophrenia. Neurosci Biobehav Rev 2006; 30:551-61. [PMID: 16445981 DOI: 10.1016/j.neubiorev.2005.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 10/27/2005] [Accepted: 10/27/2005] [Indexed: 12/18/2022]
Abstract
Decreased expression of a subset of oligodendrocyte and myelin-related genes is the most consistent finding among gene expression studies of postmortem brain tissue from subjects with schizophrenia (SCZ), although heritable variants have yet to be found that can explain the bulk of this data. However, expression of the glial gene Quaking (QKI), encoding an RNA binding (RBP) essential for myelination, was recently found to be decreased in SCZ brain. Both oligodendrocyte/myelin related genes, and other RBPs that are known or predicted to be targets of QKI, are also decreased in SCZ. Two different quaking mutant mice share some pathological features in common with SCZ, including decreased expression of myelin-related genes and dysmyelination, without gross destruction of white matter. Therefore, although these mice are not a model of SCZ per se, understanding the similarities and differences in gene expression between brains from these mice and subjects with SCZ could help parse out distinct genetic pathways underlying SCZ.
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Affiliation(s)
- L Alison McInnes
- Department of Psychiatry and Human Genetics, Mount Sinai School of Medicine, New York, NY 10029, USA
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8
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Le Saux F, Besson MJ, Maurin Y. Abnormal postnatal ontogeny of the locus coeruleus in the epileptic mutant mouse quaking. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 136:197-205. [PMID: 12101037 DOI: 10.1016/s0165-3806(02)00386-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The tonic-clonic convulsions of the quaking mutant mice have been shown to be associated with the hyperplasia of the nucleus locus coeruleus, the origin of most brain noradrenergic neurons. In the present study, the postnatal ontogeny of the locus coeruleus has been studied by tyrosine hydroxylase immunolabeling in the mutant mice quaking and their controls at postnatal days 1, 30 and 90. In the control mice, the number of immunoreactive neuronal cell bodies increased significantly in the rostral half of the locus coeruleus between birth and postnatal day 30, while it decreased significantly in the caudal half between birth and adulthood. Thus, during postnatal maturation, the distribution of locus coeruleus neurons was shifted in the rostral direction. In the quaking mutant mice, while the increase of immunolabeling between birth and postnatal day 30 was observed in the rostral half of the locus coeruleus, no diminution could be found in the caudal half between birth and adulthood. As a result, the rostral shift of tyrosine hydroxylase immunoreactivity was not observed. Consequently, in adult mice, the caudal part of the mutants locus coeruleus appeared to contain significantly more neurons than the corresponding region in the controls. These results indicate that the hyperplasia of the locus coeruleus of the quaking mice that we had previously reported results from an alteration of the postnatal maturation of this nucleus. This developmental abnormality might be a primary determinant of the inherited epilepsy of the quaking mutant mice.
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Affiliation(s)
- Françoise Le Saux
- INSERM U 495 Hôpital de la Salpêtrière, 47 Bld de l'Hopital, 75651 Paris Cedex 13, France
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9
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Baumann N, Pham-Dinh D. Biology of oligodendrocyte and myelin in the mammalian central nervous system. Physiol Rev 2001; 81:871-927. [PMID: 11274346 DOI: 10.1152/physrev.2001.81.2.871] [Citation(s) in RCA: 1223] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Oligodendrocytes, the myelin-forming cells of the central nervous system (CNS), and astrocytes constitute macroglia. This review deals with the recent progress related to the origin and differentiation of the oligodendrocytes, their relationships to other neural cells, and functional neuroglial interactions under physiological conditions and in demyelinating diseases. One of the problems in studies of the CNS is to find components, i.e., markers, for the identification of the different cells, in intact tissues or cultures. In recent years, specific biochemical, immunological, and molecular markers have been identified. Many components specific to differentiating oligodendrocytes and to myelin are now available to aid their study. Transgenic mice and spontaneous mutants have led to a better understanding of the targets of specific dys- or demyelinating diseases. The best examples are the studies concerning the effects of the mutations affecting the most abundant protein in the central nervous myelin, the proteolipid protein, which lead to dysmyelinating diseases in animals and human (jimpy mutation and Pelizaeus-Merzbacher disease or spastic paraplegia, respectively). Oligodendrocytes, as astrocytes, are able to respond to changes in the cellular and extracellular environment, possibly in relation to a glial network. There is also a remarkable plasticity of the oligodendrocyte lineage, even in the adult with a certain potentiality for myelin repair after experimental demyelination or human diseases.
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Affiliation(s)
- N Baumann
- Institut National de la Santé et de la Recherche Médicale U. 495, Biology of Neuron-Glia Interactions, Salpêtrière Hospital, Paris, France.
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10
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Ma PM. Catecholaminergic systems in the zebrafish. I. Number, morphology, and histochemical characteristics of neurons in the locus coeruleus. J Comp Neurol 1994; 344:242-55. [PMID: 8077459 DOI: 10.1002/cne.903440206] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The locus coeruleus is a noradrenergic nucleus located in the isthmal tegmentum. In mammals, it contains several thousand neurons that have diverse projection patterns and contain various neuropeptides. In fishes, this nucleus contains few neurons. This study attempts to define and quantify morphological types of locus coeruleus neurons, and search for neurochemical subpopulations in the zebrafish. In this fish, the locus coeruleus contains between 3 and 10 neurons, and most nuclei contain between 5 and 8 cells. Nuclei in more inbred lines of fish have a narrower range of neurons. The difference in neuron number between the two sides of the same brain is small, but only 24% of the brains have identical numbers on both sides. These observations suggest that there is a two-step control of neuron number: the genetic constitution of the fish determines the approximate number of cells, while epigenetic factors determine the final number. Based on dendritic orientation, three types of cells are identified: (1) V type, neurons with only ventrally projecting dendrites; (2) L type, neurons with only laterally projecting dendrites; and (3) VL type, neurons with both ventrally and laterally projecting dendrites. Over 65% of the neurons are of the V type; some nuclei have V type cells only. There is a correlation between the total number of neurons and the ratio of each cell type. In nuclei with five cells or fewer, over 80% of the neurons are V type; higher percentages of the other two types are seen in nuclei with 6 or more neurons. The dendritic morphology and orientation suggest that various types of neurons may receive different inputs. Cholinesterases are not detectable in locus coeruleus neurons. Immunocytochemical staining for a number of neuropeptides also fails to demonstrate detectable levels. Neuropeptide Y is present in some cells abutting the locus coeruleus, but these are probably not catecholamine-containing neurons. Some neurons contain choline-acetyltransferase. These observations suggest that locus coeruleus neurons of the zebrafish may be morphologically and neurochemically heterogeneous.
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Affiliation(s)
- P M Ma
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
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Hara M, Sasa M, Kawabata A, Serikawa T, Yamada T, Yamada J, Takaori S. Decreased dopamine and increased norepinephrine levels in the spontaneously epileptic rat, a double mutant rat. Epilepsia 1993; 34:433-40. [PMID: 8504778 DOI: 10.1111/j.1528-1157.1993.tb02583.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Dopamine (DA) and norepinephrine (NE) brain levels and turnover rate were examined in the spontaneously epileptic rat (SER: zi/zi, tm/tm), a double mutant rat obtained by mating tremor heterozygotes (tm/+) with zitter homozygotes associated with epileptic seizures composed of spontaneously occurring tonic convulsion and absence-like seizure. DA and NE levels were also determined in age-matched male zitter, tremor and Kyo: Wistar rats. DA levels in caudate nucleus were significantly lower in adult age (10-12 weeks) SER, which showed epileptic seizures, and zitter rats than in adult Kyo: Wistar and tremor rats. DA levels in other areas such as thalamus-hypothalamus, midbrain, and pons medulla were not different among SER, zitter, tremor, and Kyo: Wistar rats at age 10-12 weeks. Except in cerebral cortex and hippocampus, there were no differences in brain DA levels between young seizure-free SER (age 5 weeks) and young Kyo: Wistar rats. Furthermore, the turnover rate of DA was significantly lower in caudate nucleus of adult SER than of Kyo: Wistar rat, whereas in pons-medulla there was no difference between the two strains. In contrast, NE levels in the thalamus-hypothalamus, midbrain, cerebellum and pons-medulla were higher in SER and zitter rats at age 10-12 weeks than in age-matched tremor and Kyo: Wistar rats. Higher NE levels were also observed in midbrain, cerebellum, and pons-medulla of young SER as compared with young Kyo: Wistar rats. Turnover rates of NE were significantly lower in pons-medulla and cerebellum of the adult SER than in those of Kyo: Wistar rat.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Hara
- Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan
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12
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Mitrovic N, Le Saux F, Gioanni H, Gioanni Y, Besson MJ, Maurin Y. Distribution of [3H]clonidine binding sites in the brain of the convulsive mutant quaking mouse: a radioautographic analysis. Brain Res 1992; 578:26-32. [PMID: 1511279 DOI: 10.1016/0006-8993(92)90225-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The radioautographic analysis of [3H]clonidine binding was performed on brain slices from the convulsive mutant mice quaking and their controls of the same strain. In the quaking mice significant increases were observed mostly in the brainstem and the cerebellum, but also in a few regions of the forebrain, such as the lateral and medial thalamic nuclei, the medial geniculate nucleus, the amygdala and the hypothalamus. Other regions, such as the cerebral cortex and the hippocampus, which are classically involved in various models of epilepsy, but not in the quaking mice, did not show any modification of [3H]clonidine binding. A high degree of correlation was found between the structures with an increased density of alpha 2-adrenoceptor binding sites and the distribution of regions from which seizures can be elicited by intracerebral electrical stimulation in head-restrained quaking mice. This comparison emphasizes the role of noradrenaline acting at the level of alpha 2-adrenoceptors in the epileptic syndrome of the quaking mutants.
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Affiliation(s)
- N Mitrovic
- Laboratoire de Neurochimie Anatomie, UPMC-CNRS UA 1199, Paris, France
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13
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Gioanni Y, Gioanni H, Mitrovic N. Seizures can be triggered by stimulating non-cortical structures in the quaking mutant mouse. Epilepsy Res 1991; 9:19-31. [PMID: 1884716 DOI: 10.1016/0920-1211(91)90043-f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mutant Quaking mice (C57BL/6J) display convulsive tonic-clonic seizures that can be either spontaneous or triggered by manipulation of the animal or by auditory stimulation. Several abnormalities have been found (especially in the noradrenergic system) in the brainstem of this mutant strain. We first verified by electrophysiological recording that the cerebral cortex was not involved in the generation or in the development of these fits. Then we showed that tonic-clonic seizures similar to those obtained in the freely moving animal were triggered by low-threshold (LT, 5-50 microA) or high-threshold (HT, 55-150 microA) stimuli performed during head restraint. LT stimuli were mostly efficient in a number of ponto-bulbar and mesencephalic structures, including several reticular nuclei, the locus coeruleus, the nucleus subcoeruleus and the red nucleus, whereas HT stimuli were generally necessary to trigger fits by stimulating the nuclei pontis, the substantia nigra, the central gray area and the cerebellar nuclei. Seizures were also provoked at the diencephalic level with LT stimulation delivered in the medial thalamic area, the nucleus reticularis thalami and some subthalamic regions (zona incerta, H field of Forel). In contrast, no fits were obtained by stimulating the cerebellar cortex and the inferior colliculus, the ventral and lateral groups of thalamic nuclei or the telencephalic regions (hippocampus, amygdala, caudate nucleus, putamen and cerebral cortex), with the exception of the globus pallidus.
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Affiliation(s)
- Y Gioanni
- Institut des Neurosciences CNRS, Université P. & M. Curie, Paris, France
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14
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Maurin Y, Besson MJ, Mitrovic N. Alteration of the NMDA associated ion channel binding sites in the epileptic mutant mouse quaking. Amino Acids 1990. [DOI: 10.1007/978-94-011-2262-7_37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Abstract
The study of mechanisms of the epilepsies requires employment of animal models. Choice of a model system depends upon several factors, including the question to be studied, the type of epilepsy to be modelled, familiarity and convenience. Over 50 models are reviewed. Major categories of models are those for simple partial seizures: topical convulsants, acute electrical stimulation, cortically implanted metals, cryogenic injury; for complex partial seizures: kainic acid, tetanus toxin, injections into area tempesta, kindling, rodent hippocampal slice, isolated cell preparations, human neurosurgical tissue; for generalized tonic-clonic seizures: genetically seizure-prone strains of mouse, rat, gerbil, fruitfly and baboon, maximal electroshock seizures, systemic chemical convulsants, metabolic derangements; and for generalized absence seizures: thalamic stimulation, bilateral cortical foci, systemic penicillin, gamma-hydroxy-butyrate, intraventricular opiates, genetic rat models. The lithium-pilocarpine, homocysteine and rapid repetitive stimulation models are most useful in studies of status epilepticus. Key findings learned from each of the models, the model's strengths and weaknesses are detailed. Interpretation of findings from each of these models can be difficult. Do results pertain to the epilepsies or to the particular model under study? How important are species differences? Which clinical seizure type is really being modelled? In a model are behavior or EEG findings only similar superficially to epilepsy, or are the mechanisms comparable? The wealth of preparations available to model the epilepsies underscores the need for unifying themes, and for better understanding of basic mechanisms of the epilepsies.
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Affiliation(s)
- R S Fisher
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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16
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Hof PR, Celio MR, Magistretti PJ. Age-dependent supersensitivity to the glycogenolytic effect of K+ in the cerebral cortex of the spontaneously epileptic quaking mouse mutant. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1989; 46:107-13. [PMID: 2706764 DOI: 10.1016/0165-3806(89)90147-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
K+, at concentrations reached in the extracellular space during neuronal activity (5-10 mM), promotes a time- and concentration-dependent hydrolysis of [3H]glycogen newly synthesized by mouse cerebral cortical slices. In the present study, the glycogenolytic action of K+ was examined in the neocortex of the quaking mouse, a spontaneously epileptic mutant characterized by deficient myelination of the CNS. The potency and efficacy of K+ in eliciting glycogen hydrolysis was greatly enhanced in cerebral cortical slices prepared from homozygous quaking mice (qk/qk) older than 7 weeks of age, indicating a supersensitive response to a metabolic action of the ion. A detailed ontogenic analysis showed an evolution of the supersensitive response to K+ which is reminiscent of the previously described increase in the number of alpha 2-adrenoreceptors in the brainstem of this mutant. In contrast to the altered response to K+, the glycogenolytic action of noradrenaline and vasoactive intestinal peptide reported earlier was equally expressed in qk/qk and in their unaffected littermates.
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Affiliation(s)
- P R Hof
- Département de Pharmacologie, Centre Médical Universitaire, Geneva, Switzerland
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17
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Characteristics of the brain dopamine system in mice with the neurological quaking mutation. Bull Exp Biol Med 1988. [DOI: 10.1007/bf00840388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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O'Kusky JR, Boyes BE, McGeer EG. Methylmercury-induced movement and postural disorders in developing rat: regional analysis of brain catecholamines and indoleamines. Brain Res 1988; 439:138-46. [PMID: 3359179 DOI: 10.1016/0006-8993(88)91470-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Subcutaneous administration of methylmercury (MeHg) to rats during early postnatal development resulted in movement and postural disorders by day 22-24. Tissue concentrations of norepinephrine (NE), serotonin (5-HT), dopamine (DA) and selected metabolites were measured in the cerebral cortex, spinal cord and caudate-putamen at the onset of neurological impairment and at two subclinical stages of toxicity. In the cerebral cortex there was a significant increase in tissue concentrations of 5-HT (54-81%) and 5-hydroxyindoleacetic acid (HIAA, 133-178%) at the onset of neurological impairment. Similar increases were detected in the spinal cord for 5-HT (19-43%) and HIAA (98-123%) as well as an increase in the concentration of NE (42-51%). In the caudate-putamen there were significant increases in the concentrations of NE (98-116%), HIAA (108-124%) and DA (28-29%) with a significant decrease in the concentration of 3,4-dihydroxyphenylacetic acid (DOPAC, 20-27%); however, tissue levels of homovanillic acid (HVA) did not change significantly. Many of these changes were detected at subclinical stages of MeHg toxicity. The ratio of HIAA/5-HT, which is frequently used as an estimate of turnover for 5-HT, was significantly increased in all 3 tissues at the onset of neurological impairment (38-94%) and at one subclinical stage (47-114%). The ratio of (DOPAC + HVA)/DA was significantly decreased in caudate-putamen at all 3 stages of toxicity (18-40%). These changes indicate altered metabolism in aromatic amine systems in the developing central nervous system during the pathogenesis of MeHg-induced movement and postural disorder.
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Affiliation(s)
- J R O'Kusky
- Department of Pathology, Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, Canada
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19
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Maurin Y, Enz A, Le Saux F, Besson MJ. Supernumerary locus coeruleus neurons as a determinant of inherited epilepsy in the convulsive mutant mouse quaking. Brain Res 1986; 366:379-84. [PMID: 3008913 DOI: 10.1016/0006-8993(86)91323-5] [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: 01/03/2023]
Abstract
In quaking mice (a genetic model of epilepsy with an increased number of noradrenergic neurons) bilateral electrolytic coagulation of locus coeruleus (LC) in adult mice inhibited the convulsions elicited by somatic stimulations while neonatal 6-hydroxydopamine (6-OHDA) treatment remained ineffective upon the convulsions. Biochemical effects of the two treatments differed only in the brainstem where electrolytic lesion decreased while 6-OHDA treatment increased noradrenaline (NA) and 3-methoxy 4-hydroxyphenylethyleneglycol (MHPG) levels. Our results suggest that supernumerary LC neurons mediate the convulsions of the mutants through an action presumably restricted to the brainstem.
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