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Powell CL, Davidson AR, Brown AM. Universal Glia to Neurone Lactate Transfer in the Nervous System: Physiological Functions and Pathological Consequences. BIOSENSORS-BASEL 2020; 10:bios10110183. [PMID: 33228235 PMCID: PMC7699491 DOI: 10.3390/bios10110183] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/13/2022]
Abstract
Whilst it is universally accepted that the energy support of the brain is glucose, the form in which the glucose is taken up by neurones is the topic of intense debate. In the last few decades, the concept of lactate shuttling between glial elements and neural elements has emerged in which the glial cells glycolytically metabolise glucose/glycogen to lactate, which is shuttled to the neural elements via the extracellular fluid. The process occurs during periods of compromised glucose availability where glycogen stored in astrocytes provides lactate to the neurones, and is an integral part of the formation of learning and memory where the energy intensive process of learning requires neuronal lactate uptake provided by astrocytes. More recently sleep, myelination and motor end plate integrity have been shown to involve lactate shuttling. The sequential aspect of lactate production in the astrocyte followed by transport to the neurones is vulnerable to interruption and it is reported that such disparate pathological conditions as Alzheimer's disease, amyotrophic lateral sclerosis, depression and schizophrenia show disrupted lactate signalling between glial cells and neurones.
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Affiliation(s)
- Carolyn L. Powell
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (C.L.P.); (A.R.D.)
| | - Anna R. Davidson
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (C.L.P.); (A.R.D.)
| | - Angus M. Brown
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK; (C.L.P.); (A.R.D.)
- Department of Neurology, University of Washington, Seattle, WA 98105, USA
- Correspondence:
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2
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Rich LR, Harris W, Brown AM. The Role of Brain Glycogen in Supporting Physiological Function. Front Neurosci 2019; 13:1176. [PMID: 31749677 PMCID: PMC6842925 DOI: 10.3389/fnins.2019.01176] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/17/2019] [Indexed: 01/08/2023] Open
Abstract
Glycogen is present in the mammalian brain but occurs at concentrations so low it is unlikely to act as a conventional energy reserve. Glycogen has the intriguing feature of being located exclusively in astrocytes, but its presence benefits neurones, suggesting that glycogen is metabolized to a conduit that is transported between the glia and neural elements. In the rodent optic nerve model glycogen supports axon conduction in the form of lactate to supplement axonal metabolism during aglycemia, hypoglycemia and during periods of increased energy demand under normoglycemic conditions. In the hippocampus glycogen plays a vital role in supplying the neurones with lactate during memory formation. The physiological processes that glycogen supports, such as learning and memory, imply an inclusive and vital role in supporting physiological brain functions.
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Affiliation(s)
- Laura R Rich
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - William Harris
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Angus M Brown
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.,Department of Neurology, University of Washington, Seattle, WA, United States
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3
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Brown AM, Rich LR, Ransom BR. Metabolism of Glycogen in Brain White Matter. ADVANCES IN NEUROBIOLOGY 2019; 23:187-207. [PMID: 31667810 DOI: 10.1007/978-3-030-27480-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Brain glycogen is a specialized energy buffer, rather than a conventional reserve. In the rodent optic nerve, a central white matter tract, it is located in astrocytes, where it is converted to lactate, which is then shuttled intercellularly from the astrocyte to the axon. This basic pathway was elucidated from non-physiological experiments in which the nerve was deprived of exogenous glucose. However, this shuttling also occurs under physiological conditions, when tissue energy demand is increased above baseline levels in the presence of normoglycemic concentrations of glucose. The signaling mechanism by which axons alert astrocytes to their increased energy requirement is likely to be elevated interstitial K+, the inevitable consequence of increased neuronal activity.
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Affiliation(s)
- Angus M Brown
- School of Life Sciences, University of Nottingham, Nottingham, UK. .,Department of Neurology, University on Washington, Seattle, WA, USA.
| | - Laura R Rich
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Bruce R Ransom
- School of Life Sciences, University of Nottingham, Nottingham, UK.,Department of Neurology, University on Washington, Seattle, WA, USA
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Waitt AE, Reed L, Ransom BR, Brown AM. Emerging Roles for Glycogen in the CNS. Front Mol Neurosci 2017; 10:73. [PMID: 28360839 PMCID: PMC5352909 DOI: 10.3389/fnmol.2017.00073] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/03/2017] [Indexed: 11/20/2022] Open
Abstract
The ability of glycogen, the depot into which excess glucose is stored in mammals, to act as a source of rapidly available energy substrate, has been exploited by several organs for both general and local advantage. The liver, expressing the highest concentration of glycogen maintains systemic normoglycemia ensuring the brain receives a supply of glucose in excess of demand. However the brain also contains glycogen, although its role is more specialized. Brain glycogen is located exclusively in astrocytes in the adult, with the exception of pathological conditions, thus in order to benefit neurons, and energy conduit (lactate) is trafficked inter-cellularly. Such a complex scheme requires cell type specific expression of a variety of metabolic enzymes and transporters. Glycogen supports neural elements during withdrawal of glucose, but once the limited buffer of glycogen is exhausted neural function fails and irreversible injury ensues. Under physiological conditions glycogen acts to provide supplemental substrates when ambient glucose is unable to support function during increased energy demand. Glycogen also supports learning and memory where it provides lactate to neurons during the conditioning phase of in vitro long-term potentiation (LTP), an experimental correlate of learning. Inhibiting the breakdown of glycogen or intercellular transport of lactate in in vivo rat models inhibits the retention of memory. Our current understanding of the importance of brain glycogen is expanding to encompass roles that are fundamental to higher brain function.
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Affiliation(s)
- Alice E. Waitt
- School of Life Sciences, University of NottinghamNottingham, UK
| | - Liam Reed
- School of Life Sciences, University of NottinghamNottingham, UK
| | - Bruce R. Ransom
- Department of Neurology, University of WashingtonSeattle, WA, USA
| | - Angus M. Brown
- School of Life Sciences, University of NottinghamNottingham, UK
- Department of Neurology, University of WashingtonSeattle, WA, USA
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5
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Tabansky I, Stern JNH, Pfaff DW. Implications of Epigenetic Variability within a Cell Population for "Cell Type" Classification. Front Behav Neurosci 2015; 9:342. [PMID: 26733833 PMCID: PMC4679859 DOI: 10.3389/fnbeh.2015.00342] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/23/2015] [Indexed: 11/18/2022] Open
Abstract
Here, we propose a new approach to defining nerve “cell types” in reaction to recent advances in single cell analysis. Among cells previously thought to be equivalent, considerable differences in global gene expression and biased tendencies among differing developmental fates have been demonstrated within multiple lineages. The model of classifying cells into distinct types thus has to be revised to account for this intrinsic variability. A “cell type” could be a group of cells that possess similar, but not necessarily identical properties, variable within a spectrum of epigenetic adjustments that permit its developmental path toward a specific function to be achieved. Thus, the definition of a cell type is becoming more similar to the definition of a species: sharing essential properties with other members of its group, but permitting a certain amount of deviation in aspects that do not seriously impact function. This approach accommodates, even embraces the spectrum of natural variation found in various cell populations and consequently avoids the fallacy of false equivalence. For example, developing neurons will react to their microenvironments with epigenetic changes resulting in slight changes in gene expression and morphology. Addressing the new questions implied here will have significant implications for developmental neurobiology.
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Affiliation(s)
- Inna Tabansky
- Laboratory of Neurobiology and Behavior, The Rockefeller University New York, NY, USA
| | - Joel N H Stern
- Laboratory of Neurobiology and Behavior, The Rockefeller UniversityNew York, NY, USA; Departments of Neurology and Science Education, Hofstra North Shore-LIJ School of MedicineHempstead, NY, USA; Department of Autoimmunity, The Feinstein Institute for Medical Research, North Shore-LIJ Health SystemManhasset, NY, USA
| | - Donald W Pfaff
- Laboratory of Neurobiology and Behavior, The Rockefeller University New York, NY, USA
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Cho KS, Joo SH, Choi CS, Kim KC, Ko HM, Park JH, Kim P, Hur J, Lee SH, Bahn GH, Ryu JH, Lee J, Han SH, Kwon KJ, Shin CY. Glucose deprivation reversibly down-regulates tissue plasminogen activator via proteasomal degradation in rat primary astrocytes. Life Sci 2013; 92:929-37. [DOI: 10.1016/j.lfs.2013.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 03/12/2013] [Accepted: 03/20/2013] [Indexed: 11/30/2022]
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Abstract
The brain contains glycogen but at low concentration compared with liver and muscle. In the adult brain, glycogen is found predominantly in astrocytes. Astrocyte glycogen content is modulated by a number of factors including some neurotransmitters and ambient glucose concentration. Compelling evidence indicates that astrocyte glycogen breaks down during hypoglycemia to lactate that is transferred to adjacent neurons or axons where it is used aerobically as fuel. In the case of CNS white matter, this source of energy can extend axon function for 20 min or longer. Likewise, during periods of intense neural activity when energy demand exceeds glucose supply, astrocyte glycogen is degraded to lactate, a portion of which is transferred to axons for fuel. Astrocyte glycogen, therefore, offers some protection against hypoglycemic neural injury and ensures that neurons and axons can maintain their function during very intense periods of activation. These emerging principles about the roles of astrocyte glycogen contradict the long held belief that this metabolic pool has little or no functional significance.
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Affiliation(s)
- Angus M Brown
- School of Biomedical Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2UH, United Kingdom
- Department of Neurology, University of Washington, Seattle, Washington, USA
| | - Bruce R Ransom
- School of Biomedical Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2UH, United Kingdom
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Brown AM, Baltan Tekkök S, Ransom BR. Energy transfer from astrocytes to axons: the role of CNS glycogen. Neurochem Int 2004; 45:529-36. [PMID: 15186919 DOI: 10.1016/j.neuint.2003.11.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Accepted: 11/12/2003] [Indexed: 10/26/2022]
Abstract
We tested the hypothesis that astrocytic glycogen supports axon function under both pathological and physiological conditions. Functional activity of the rat (RON) or mouse optic nerve (MON), representative central white matter tracts, was assessed electrophysiologically as the area under the supramaximal compound action potential (CAP). During aglycaemia the CAP area of rodent optic nerve persisted for up to 30 min, after which the CAP rapidly failed. Glycogen content measured biochemically during the aglycaemic insult fell with a time course compatible with its rapid degradation in the absence of glucose. Pharmacological up-regulation of glycogen content prior to the aglycaemic insult with incubation in hyperglycaemic ambient glucose delayed CAP failure, whereas down-regulation of glycogen content induced by nor-adrenaline accelerated CAP failure. Inhibiting lactate transfer between astrocytes and axons during aglycaemia, where glycogen is the only utilisable energy reserve, resulted in accelerated CAP failure, implying that glycogen-derived lactate supports function when exogenous energy metabolites are withdrawn. Under normoglycaemic conditions glycogen content decreased during high frequency axon discharge, although CAP function was fully maintained. Both prior depletion of glycogen content, or blocking axonal lactate uptake rendered nerves incapable of fully supporting CAP function during high frequency firing in the presence of normoglycaemic glucose. These results indicated that during aglycaemia and increased metabolic demand, astrocytic glycogen was degraded to form lactate, which was used as a supplemental energy source when ambient normoglycaemic glucose was incapable of meeting immediate tissue energy demands.
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Affiliation(s)
- Angus M Brown
- Department of Neurology, University of Washington School of Medicine, Box 3356465, 1959 NE Pacific St., Seattle, WA 98195, USA.
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9
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Abstract
The mammalian brain contains glycogen, which is located predominantly in astrocytes, but its function is unclear. A principal role for brain glycogen as an energy reserve, analogous to its role in the periphery, had been universally dismissed based on its relatively low concentration, an assumption apparently reinforced by the limited duration that the brain can function in the absence of glucose. However, during insulin-induced hypoglycaemia, where brain glucose availability is limited, glycogen content falls first in areas with the highest metabolic rate, suggesting that glycogen provides fuel to support brain function during pathological hypoglycaemia. General anaesthesia results in elevated brain glycogen suggesting quiescent neurones allow glycogen accumulation, and as long ago as the 1950s it was shown that brain glycogen accumulates during sleep, is mobilized upon waking, and that sleep deprivation results in region-specific decreases in brain glycogen, implying a supportive functional role for brain glycogen in the conscious, awake brain. Interest in brain glycogen has recently been re-awakened by the first continuous in vivo measurements using NMR spectroscopy, by the general acceptance of metabolic coupling between glia and neurones involving intercellular transfer of energy substrate, and by studies supporting a prominent physiological role for brain glycogen as a provider of supplemental energy substrate during periods of increased tissue energy demand, when ambient normoglycaemic glucose is unable to meet immediate energy requirements.
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Affiliation(s)
- Angus M Brown
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.
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10
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Faltin J, Lodin Z, Hartman J, Foucaud B, Gombos G, Sensenbrenner M. Morphological maturation and survival of chicken and rat embryonic neurons on different culture substrata. Int J Dev Neurosci 2003; 3:111-21. [DOI: 10.1016/0736-5748(85)90002-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/1984] [Indexed: 10/27/2022] Open
Affiliation(s)
- J. Faltin
- Institute of Physiology, Czechoslovak Academy of Sciences; Prague Czechoslovakia
| | - Z. Lodin
- Institute of Physiology, Czechoslovak Academy of Sciences; Prague Czechoslovakia
| | - J. Hartman
- Institute of Physiology, Czechoslovak Academy of Sciences; Prague Czechoslovakia
| | - B. Foucaud
- Institute of Physiology, Czechoslovak Academy of Sciences; Prague Czechoslovakia
- Centre de Neurochimie du C.N.R.S.; 5, rue Blaise Pascal 67084 Strasbourg Cédex France
| | - G. Gombos
- Institute of Physiology, Czechoslovak Academy of Sciences; Prague Czechoslovakia
- Centre de Neurochimie du C.N.R.S.; 5, rue Blaise Pascal 67084 Strasbourg Cédex France
| | - M. Sensenbrenner
- Institute of Physiology, Czechoslovak Academy of Sciences; Prague Czechoslovakia
- Centre de Neurochimie du C.N.R.S.; 5, rue Blaise Pascal 67084 Strasbourg Cédex France
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11
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Burbach JP, Luckman SM, Murphy D, Gainer H. Gene regulation in the magnocellular hypothalamo-neurohypophysial system. Physiol Rev 2001; 81:1197-267. [PMID: 11427695 DOI: 10.1152/physrev.2001.81.3.1197] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The hypothalamo-neurohypophysial system (HNS) is the major peptidergic neurosecretory system through which the brain controls peripheral physiology. The hormones vasopressin and oxytocin released from the HNS at the neurohypophysis serve homeostatic functions of water balance and reproduction. From a physiological viewpoint, the core question on the HNS has always been, "How is the rate of hormone production controlled?" Despite a clear description of the physiology, anatomy, cell biology, and biochemistry of the HNS gained over the last 100 years, this question has remained largely unanswered. However, recently, significant progress has been made through studies of gene identity and gene expression in the magnocellular neurons (MCNs) that constitute the HNS. These are keys to mechanisms and events that exist in the HNS. This review is an inventory of what we know about genes expressed in the HNS, about the regulation of their expression in response to physiological stimuli, and about their function. Genes relevant to the central question include receptors and signal transduction components that receive and process the message that the organism is in demand of a neurohypophysial hormone. The key players in gene regulatory events, the transcription factors, deserve special attention. They do not only control rates of hormone production at the level of the gene, but also determine the molecular make-up of the cell essential for appropriate development and physiological functioning. Finally, the HNS neurons are equipped with a machinery to produce and secrete hormones in a regulated manner. With the availability of several gene transfer approaches applicable to the HNS, it is anticipated that new insights will be obtained on how the HNS is able to respond to the physiological demands for its hormones.
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Affiliation(s)
- J P Burbach
- Rudolf Magnus Institute for Neurosciences, Section of Molecular Neuroscience, Department of Medical Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands.
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12
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Ogiso M, Ohta M, Harada Y, Hirano S. Neuronal ganglioside increases dependent on the neuron--glia interaction in primary culture. J Neurochem 1992; 59:636-43. [PMID: 1629734 DOI: 10.1111/j.1471-4159.1992.tb09417.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: 12/28/2022]
Abstract
Dissociated neuronal cells from rat embryonic hemispheres were cultivated on astroglial layers. The increase in ganglioside content of the cocultures was more rapid than that of neuronal cultures seeded on polylysine surfaces for the first 24 h, and the extent of the increase was greater 7 days after inoculation, probably because of interaction between the preformed astroglial layers and the neuronal cells in vitro. The promoted expression of the a-pathway gangliosides, GM1 and GD1a, was recognized by TLC and the increase in GM1 was immunologically ascertained. The incorporation of 3H-labeled N-acetyl-D-mannosamine into GD3 and b-series gangliosides was elevated for the first 24 h. However, cocultures in which there was no contact between neuronal cells and the astroglial sheet showed no appreciable increase in incorporation. Thus, cell surface changes were induced at the membrane glycolipid level in the neuronal cells by contact with astroglial layers. The synthesis and expression of neuronal gangliosides are discussed in relation to the onset of neuron--glia interaction.
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Affiliation(s)
- M Ogiso
- Department of Physiology, Toho University School of Medicine, Tokyo, Japan
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13
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Mangoura D, Vernadakis A. GABAergic neurons in cultures derived from three-, six- or eight-day-old chick embryo: a biochemical and immunocytochemical study. Brain Res 1988; 468:25-35. [PMID: 3378184 DOI: 10.1016/0165-3806(88)90004-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cultures were prepared from 3-, 6- and 8-day-old chick embryos. Whole chick embryos were dissociated by sieving through a nylon mesh for E3 cultures and cerebral hemispheres for E6 and E8 cultures. The dispersed cells were plated onto poly-L-lysine coated culture dishes in Dulbecco's modified Eagle's medium, containing 10% fetal bovine calf serum. Growth patterns in these cultures have been previously described. Biochemical and immunocytochemical markers were used to identify GABAergic neurons in culture. Neurons exhibiting GABA-like immunoreactivity were present in all 3 types of cultures as early as 4-6 days in culture. The developmental profile of glutamic acid decarboxylase (GAD) derived from 3-day-old whole chick embryo cultures showed low activities whereas the enzyme activity markedly rose in cultures derived from 6- or 8-day-old chick embryo cerebral hemispheres during the first two weeks. The changes in GAD activity observed in these cultures are interpreted to reflect the maturational state of GABAergic neurons and also their responsiveness to microenvironmental factors.
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Affiliation(s)
- D Mangoura
- Department of Psychiatry, University of Colorado School of Medicine, Denver 80262
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Barbin G, Selak I, Manthorpe M, Varon S. Use of central neuronal cultures for the detection of neuronotrophic agents. Neuroscience 1984; 12:33-43. [PMID: 6379502 DOI: 10.1016/0306-4522(84)90135-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Neuronotrophic factors, a class of macromolecules thought to be present within the neuronal environment are required to support the survival in vitro of peripheral neurons. In the present study we have established bioassay culture systems suitable for the identification of similar agents for intrinsic neurons of the central nervous system. The striatum, hippocampus and septum of 18 day fetal rats were dissociated and plated in a serum-free medium on a neurite conducive substratum which allows an easy recognition of neurons under phase contrast microscopy. These cultures contain predominantly neurons as assessed by tetanus toxin labelling, a well recognized neuronal marker. Seeding the cell suspensions at decreasing densities yields after 24 h a density dependent survival of the neuronal population. Thus a low seeding density could be chosen where survival of these neurons required an exogenous source of trophic factors. Survival of central neurons was promoted by several conditioned media derived from rodent glial cell cultures, both primary (astroglia, Schwann) and clonal (C6 glioma, Schwannoma). Serial dilutions of these media allowed the titration of their respective neuronotrophic activities. In addition, conditioned media derived from the central neuronal cultures themselves, when seeded at a high density, were also able to support the survival of low density seeded central neurons.
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15
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Lolait SJ, Lim AT, Dahl DD, Funder JW, Toh BH. Cells in neonatal rat hypothalamus primary culture--an immunofluorescence study. Neurosci Lett 1983; 43:137-42. [PMID: 6424063 DOI: 10.1016/0304-3940(83)90177-5] [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: 01/20/2023]
Abstract
Hypothalami from 1 day neonatal rats were dissociated and cultured for 4-16 days. Using immunofluorescence and antisera against neurofilament (NF) peptides, glial fibrillary acidic protein (GFAP), galactocerebroside and fibronectin we have distinguished neurons, astrocytes, oligodendrocytes and fibroblast-like cells in culture. Astrocytes initially grew as islets of 15-30 cells which dispersed as the culture aged. These cells, together with fibronectin-reactive flat cells, formed a monolayer upon which ovoid and process-bearing cells grew after 4 days in culture. Neurofilament-positive neurons constituted 5-10% of the total cell population. In maturing cultures the number of neurons decreased and fibroblasts increased. Oligodendrocytes represented less than 1% of total cell population. These studies emphasize the necessity of using the complementary techniques of morphology and immunocytochemistry for the characterization of hypothalamic neural cells in vitro.
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16
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Abstract
We have developed a rapid, specific, in vitro method for quantitatively assessing neurotoxicity of antitumour drugs and related compounds. Using cultures of foetal rat hypothalamic neurones and a staining procedure which specifically identifies neuronal cells, the neurotoxicity of 8 antitumour drugs has been evaluated. The order of neurotoxicity appears to correlate well with their known relative clinical toxicities. Neurotoxicity of the radiosensitizer misonidazole was also identified using this system. This method appears to provide a valuable preclinical screen for neurotoxicity which may be particularly useful in the development of new antitumour drug analogues and radiosensitizers.
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17
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Buse E, Matthaei H. Single neuron cultivation of embryonic and perinatal rabbit or rat brains based on plasma clot technique. Brain Res 1983; 283:221-34. [PMID: 6850350 DOI: 10.1016/0165-3806(83)90179-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Isolated neuronal cells dissociated from the brain of embryonic rabbits on the sixteenth day of gestation and of perinatal rats (eighteenth embryonic day, to E18, thirteenth day postnatum, p.n. 13) were selectively cultured using a plasma clot technique. The cells grown were shown to be neurons by means of the neuron-specific synaptosomal plasma membrane antibody (SPM). They differentiated at a very high frequency from rounded cells lacking processes into different shapes characteristic for several neuronal cell types. Morphological differences could be distinguished even after 24 h in culture. The neurons differentiated in vitro for up to 11 days, apparently without need of any direct intercellular contact. Cells caught inside the plasma clot were prevented from decreasing in number. This provides the opportunity to culture few neurons even from an extremely small area of a single brain. As an example, different cell types are shown originating from rat cerebella aged E18 to p.n. 13. Their appearance apparently corresponds to the genesis of cerebellar cell types, as is known from the in vivo situation. The high degree of characteristic neuronal differentiation and the prevention of direct intercellular contacts indicate that this culture method may serve as an in vitro assay for genetically fixed properties acquired in vivo.
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18
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Abstract
The production of laminin by early rat astrocytes in primary culture was investigated by double immunofluorescence staining for laminin and the glial fibrillary acidic protein (GFAP), a defined astrocyte marker. In early cultures (3 d in vitro; 3 DIV) cytoplasmic laminin was detected in all the GFAP-positive cells which formed the major population (80%) of the nonneuronal cells present in cultures from 20-21-d embryonic, newborn, or 5-d-old rat brains. Monensin treatment (10 microM, 4 h) resulted in accumulation of laminin in the Golgi region, located using labeled wheat germ agglutinin. Laminin started gradually to disappear from the cells with the time in culture, was absent in star-shaped, apparently mature astrocytes, but remained as pericellular matrix deposits. The disappearance of cellular laminin was dependent on the age of the animal and the time in culture so that it started earlier in cultures from 5-d-old rat brains (5 DIV) and approximately following the in vivo age difference in cultures from newborn (12 DIV) and embryonic (14 DIV) rat brains. Our results indicate that laminin is a protein of early astrocytes and also deposited by them in primary culture, thus suggesting a role for this glycoprotein in the development of the central nervous system.
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19
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Abstract
Cell cultures of olfactory bulb from 2-3-day-old rats were used to evaluate 6 antimitotic drugs for their effects on neuronal survival. In cultures grown in medium without drugs for 7 days, neurons died as a layer of non-neuronal cells proliferated. A series of experiments were performed to determine dilutions and exposure times that allow maximum neuronal survival for each of the antimitotic drugs. Use of bromodeoxyuridine (BUdR) at 10(-5) M with a 5 day exposure gave cultures with large aggregates of neurons and an extensive network of interconnecting neurites. Cytosine arabinoside (Ara-C) at 8 X 10(-6) M for 5 days of exposure was also effective but the aggregates contained cellular debris. Fluorodeoxyuridine (FUdR) at 10(-4) for 5 days was less effective in flowing neurons to survive. Methotrexate (MTX), high thymidine and hydroxyurea were all not effective in allowing neuronal survival. In all cases there was an inverse relationship between the survival of neurons and proliferation of non-neuronal cells. Additional experiments were performed to determine how proliferating non-neuronal cells can lead to the death of neurons. In a series of transfer experiments, cultures were exposed to conditioned medium. Cultured olfactory bulb neurons grown on small cover slips were exposed to BUdR under optimal conditions and after 7 days were transferred to cultures treated or not treated with BUdR. In cultures not treated with BUdR, most of the transferred BUdR treated neurons died, while in cultures treated with BUdR the BUdR treated neurons survived. These results suggest that antimitotics enhance olfactory bulb neuronal survival by reducing the number of non-neuronal cells. In addition, it appears that proliferating non-neuronal cells are responsible for neuronal cell death by a medium factor and not by contact with the dividing non-neuronal cells.
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Nicholson DM, Mason WT. Cultured neurones from the mature bovine mediobasal hypothalamus contain LHRH but not catecholamine. Brain Res 1982; 249:123-35. [PMID: 6182943 DOI: 10.1016/0006-8993(82)90176-7] [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: 01/18/2023]
Abstract
The in vitro culture of mature neurones from bovine mediobasal hypothalamus (MBH) is reported, providing a model for studies of mammalian neurosecretion at the cellular level. Explant tissue cultures of mature bovine MBH containing the arcuate nucleus were examined for LHRH, ACTH and catecholamines with a view to investigating the control of prolactin and gonadotropin secretion. LHRH immunoreactivity was found in both neuronal and non-neuronal cells in the outgrowth monolayer region of the explant. Neurones in this region appeared able to attach to a substrate and regenerate, in monolayer culture, well developed neurites characterized by beaded swellings as observed in vivo. Neither ACTH immunoreactivity nor catecholamine fluorescence was detected. Cultured neurones and astrocytes were labelled by tetanus toxin and anti-GFAP, respectively. Double labelling of cultures with tetanus toxin and anti-LHRH demonstrated the neuronal nature of many LHRH-immunoreactive cells. Radio-immunoassay data confirmed the presence of LHRH in the cultures but application of 60 mM KC1 failed to evoke hormone release. These studies have confirmed the view of previous workers that hypothalamic control of prolactin secretion in the bovine may be very different from that thought to occur in non-ruminants such as the rat and guinea pig. Finally, this work demonstrates that a cultured system from the mature bovine may prove a good model for study of neuronal regulation of gonadotropin secretion by the bovine mediobasal hypothalamus.
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