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  • 1
    Digitale Medien
    Digitale Medien
    Acetylation and Phosphorylation of Histones and Nonhistone Chromosomal Proteins in Neuronal and Glial Nuclei Purified from Cerebral Hemispheres of Developing Rat Brain (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 46 (1986), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The processes of acetylation and phosphorylation of histones and nonhistone proteins (NHPs) in neuronal and glial nuclei purified from cerebral hemispheres of rats at 1, 10, and 30 days of age were investigated. Purified neuronal and glial nuclei were incubated in the presence of [3H]acetyl-CoA and of [γ-32P]ATP. Histones and NHPs were extracted and fractionated by gel electrophoresis. Densitometric and radioactive patterns were obtained. The results showed an increase of acetylation and phosphorylation from 1 to 10 and 30 days of age in both neuronal and glial nuclei in almost all histone and NHP fractions. Among the histones, the H3 fraction was always more labeled than the other fractions and showed the most remarkable differences during postnatal development. In the NHP fractions, the increase in acetylation from 1 to 10 and 30 days of age was more evident in the low-molecular-weight region of neuronal nuclei than in the corresponding fraction of glial nuclei. The appearance of highly phosphorylated proteins (70,000–90,000 daltons)—absent at 1 day, appearing at 10 days, and more evident at 30 days of age—was observed in both neuronal and glial nuclei.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1986.tb08508.x
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  • 2
    Digitale Medien
    Digitale Medien
    Growth Conditions Differentially Regulate the Expression of α-Amino-3-Hydroxy-5-Methylisoxazole-4-Propionate (AMPA) Receptor Subunits in Cultured Neurons (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 61 (1993), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We have studied the expression of a-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor subunits in cultured cerebellar granule cells [7 days in vitro (DIV)] grown in medium containing different concentrations of K± (10, 25, or 40 mM) with or without 100 μM N-methyl-D-aspartate (NMDA; added once after 2 DIV). All these conditions are known to influence maturation and survival of granule cells, as well as the functional expression of NMDA receptors during development in culture. The expression of both glutamate receptor (GluR) subunit 1 mRNA and receptor protein was low in cultures grown in 10 mM K± (K10) and increased dramatically in cultures grown in 25 mM K± (K25), with intermediate levels found in cultures grown in K10 and chronically exposed to NMDA (K10 ± NMDA). In cultures grown in 40 mM K± (K40), the expression of GluR1 mRNA and receptor protein was lower than in K25 but still higher than in K10. GluR2 and -3 subunits were differently regulated by growth conditions, with their expression being higher in K10 and progressively reduced to the lowest levels in K40 (both mRNA and receptor proteins). GluR4 mRNA levels did not differ between K10 and K25, although they were reduced by chronic exposure to NMDA. To test how the differential expression of the various subunits affects the functional activity of AMPA receptors, we have measured AMPA-stimulated 4SCa2± influx and 40-[3H]phorbol 12, 13-dibutyrate binding in intact cells. Both functional parameters increased along with the K± concentration and were maximal in K40, in coincidence with the lowest expression of the GluR2 subunits. These results indicate that functional diversity of AMPA receptors can be generated by the degree of chronic depolarization and/or exposure to NMDA in neurons developing in primary culture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1993.tb07451.x
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  • 3
    Digitale Medien
    Digitale Medien
    Expression of Neurotrophins and Their Receptors in Primary Astroglial Cultures: Induction by Cyclic AMP-Elevating Agents (1994)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 63 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: By northern blot analysis and ribonuclease protection assay, we observed the presence of a high level of trkB mRNA in primary brain cultures devoid of neuronal cells and highly enriched in glial fibrillary acidic protein-positive astroglial cells prepared from newborn rat cerebral hemispheres, cerebral cortex, hippocampus, and striatum. In primary astroglial cultures, the more abundant trkB transcripts code for the truncated receptor without tyrosine kinase activity; probes specific for the full-length trkB mRNA did not detect any signal in northern blot analysis. By the sensitive ribonuclease protection assay, we could show the presence of trkC mRNA in cultured astrocytes, whereas no trkA mRNA was detected. We confirmed the presence of relatively high levels of nerve growth factor and neurotrophin-3 mRNA, and very low basal level of brain-derived neurotrophic factor mRNA. Moreover, we demonstrated that another member of the neurotrophin family, neurotrophin-4, is also expressed in cultured astroglial cells. In view of the fact that many functional receptors for conventional neurotransmitters or neuropeptides present on astroglial cells may act via the adenylate cyclase system, we studied also the effect of agents able to increase the intracellular cyclic AMP concentration. A sharp increase in the trkB mRNA level was observed after treatment of primary astroglial cultures with dibutyryl cyclic AMP, 8-bromo-cyclic AMP, or the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine. On the contrary, trkC mRNA levels were unaffected by treatment with cyclic AMP-elevating agents. All the neurotrophin mRNAs examined, except neurotrophin-4, were increased by 3-isobutyl-1-methylxanthine treatment. Therefore, in cultured astroglial cells, gene expression of neurotrophins and trkB is regulated by activation of the cyclic AMP-second messenger system. This process may take part in the neuronal-glial interactions during the normal neuronal activity or after injury events.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.63020509.x
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  • 4
    Digitale Medien
    Digitale Medien
    Metabotropic Glutamate Receptors in Cultured Cerebellar Granule Cells: Developmental Profile (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 60 (1993), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: Excitatory amino acid (EAA)-induced polyphosphoinositide (PPI) hydrolysis was studied during the development in culture of cerebellar granule cells. The developmental pattern was similar using metabotropic glutamate (Glu) receptor (mGluR) agonists, including L-Glu, quisqualate, and trans-(±)-1-amino-1,3-cyclopentanedicarboxylic acid: The stimulation of [3H]inositol monophosphate ([3H]-InsP) formation was low at 2 days in vitro (DIV), but the response increased steeply, reaching a peak at 4 DIV, followed by a progressive decline. In contrast, carbamylcholine-induced PPI hydrolysis exhibited a plateau after a pronounced increase during the first week in vitro. At 6 DIV, but not at 4 DIV, when the activity peaked, PPI hydrolysis elicited by Glu was reduced by the N-methyl-d-aspartate (NMDA) receptor antagonist MK-801, indicating that in cultured granule cells, NMDA receptors contribute to [3H]-InsP formation and that this component of the response develops relatively late. Accordingly, NMDA-induced [3H]-InsP formation, estimated under Mg2+-free conditions, increased markedly from very low values at 2 DIV to a plateau at 8–10 DIV. The developmental pattern of EAA-induced PPI hydrolysis was paralleled by changes in the level of an mRNA for a specific mGluR subtype (mGluR1 mRNA). RNA blot analysis performed with the pmGR1 cDNA probe revealed that the hybridization signal in RNA extracts from cultures at 1 DIV was very weak, but mGluR mRNA levels increased dramatically between 1 and 3 DIV, followed by a progressive decrease, so that by 15 DIV the mRNA levels were only ∼10% of the values at 3 DIV. These observations indicate that the functional expression of the mGluR is subject to developmental regulation, which critically involves receptor mRNA levels.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1993.tb03185.x
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  • 5
    Digitale Medien
    Digitale Medien
    Excitatory Amino Acids Stimulate Inositol Phospholipid Hydrolysis and Reduce Proliferation in Cultured Astrocytes (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 54 (1990), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: Excitatory amino acids stimulated inositol phospholipid hydrolysis in primary cultures of astrocytes, as reflected by an increased formation of [3H]inositol monophosphate ([3H]InsP) in the presence of 10 mM Li+. Quisqualate was the most potent activator of inositol phospholipid hydrolysis, followed by glutamate and ibotenate. Kainate exhibited low activity, whereas N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazolepropionate (AMPA) were inactive. The increase in [3H]InsP formation induced by glutamate was potentiated after 12-h exposure to the proliferative agent epidermal growth factor (EGF), suggesting that activation of the mitotic cycle leads to an enhanced coupling of glutamate recognition sites with phospholipase C. To study how glutamate receptors are involved in regulating cell proliferation, we have measured [methyl-3H]thymidine incorporation in cultured astrocytes. Excitatory amino acids reduced thymidine incorporation with a pharmacological profile similar to that observed for the stimulation of inositol phospholipid hydrolysis. Quisqualate acted as a potent antiproliferative agent, both under basal conditions and in cells stimulated to proliferate by addition of EGF or phorbol 12-tetradecanoate 13-acetate. Glutamate and ibotenate reduced [methyl-3H]-thymidine incorporation at high concentrations, whereas kainate, AMPA, and NMDA were virtually inactive. The action of quisqualate on both inositol phospholipid hydrolysis and thymidine incorporation was attenuated by 2-amino-4-phosphonobutyrate, which acted as a weak agonist/competitive antagonist. Other excitatory amino acid receptor antagonists were not effective. Inhibition of [methyl-3H]thymidine incorporation by quisqualate required a lag time of about 4 h and, in cells synchronized to proliferate, occurred when the drug was added during the transition between G0 and G1, but not during the S phase of the mitotic cycle. This suggests that an inducible factor may be involved in the antiproliferative effect of excitatory amino acids. Accordingly, activation of quisqualate receptors led to a rapid and transient increase in mRNA levels of the early inducible gene, c-fos. These results suggest that activation of a specific class of “quisqualate-preferring”excitatory amino acid receptors reduces proliferation of astrocytes in primary cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1990.tb02317.x
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  • 6
    Digitale Medien
    Digitale Medien
    Ciliary Neurotrophic Factor Activates JAK/Stat Signal Transduction Cascade and Induces Transcriptional Expression of Glial Fibrillary Acidic Protein in Glial Cells (1997)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 68 (1997), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: In recent reports, ciliary neurotrophic factor (CNTF) has been implicated as an injury factor involved in regulating astrogliosis in the CNS. In this study, we used a rat oligodendroglial progenitor cell line that is highly responsive to CNTF to examine CNTF-induced alterations that may play a role in activation of the glial fibrillary acidic protein (GFAP) gene. We determined that CNTF induces the transient translocation of Stat1α/p91 to the nucleus. This nuclear translocation was followed by GFAP promoter activation and an up-regulation of GFAP mRNA and protein. Levels of CNTF-α receptor mRNA, however, were unaffected by addition of the ligand. Transfection studies using an upstream 5′-flanking, 1.9-kb rat GFAP promoter linked to a luciferase reporter gene revealed CNTF-induced transcriptional activation within 1 h of ligand exposure. Moreover, serial-deleted constructs identified a distal (−1,857 to −1,546 bp) and a proximal (−384 to −106 bp) region as being important for CNTF-induced GFAP promoter activation. These two regions showed a strong degree of overlap for CNTF- and serum-induced activation of the GFAP gene. Analysis of the two regions revealed several cis-elements that are thought to be involved in GFAP regulation and/or the regulation of other genes by members of the interleukin-6 family of cytokines. Moreover, we are the first to report the presence of several putative CNTF-responsive elements within our identified distal and proximal regions in the GFAP gene promoter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1471-4159.1997.68041413.x
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  • 7
    Digitale Medien
    Digitale Medien
    Effect of EGF on DNA Labeling in Rat Cerebellar Immature Astrocytes Maintained Under Different Culture Conditions (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 633 (1991), S. 0 
    Details
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1749-6632.1991.tb15653.x
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  • 8
    Digitale Medien
    Digitale Medien
    The metabotropic glutamate receptor mGlu5 controls the onset of developmental apoptosis in cultured cerebellar neurons (1998)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 10 (1998), S. 0 
    Details
    ISSN: 1460-9568
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Cultured cerebellar granule cells grown in medium containing 10 mm K+ undergo apoptosis after 4–5 days in vitro (DIV), and, at that time, the activity of metabotropic glutamate (mGlu) receptors coupled to polyphosphoinositide (PI) hydrolysis begins to decline. In granule cells at 4 DIV, the mGlu receptor subtype mGlu5 was expressed at high levels. The expression of another PI-coupled mGlu receptor, the mGlu1a, was low at 4 DIV but increased during the following days. In cultures at 4–5 DIV, the few cells that already showed an apoptotic phenotype were devoid of mGlu5 receptors, but they all expressed mGlu1a receptors. The development of apoptosis was accelerated after treating the cultures with: (i) mGlu5 antisense oligonucleotides; (ii) the mixed mGlu receptor antagonist, (+)-α-methyl-4-carboxyphenylglycine; or (iii) the glutamate depleting enzyme, alanine aminotransferase. In contrast, an induced overexpression of mGlu5 receptors protected cultured granule cells against apoptotic death. We suggest that the activity of mGlu5 receptors supports cell survival, and a decline in the expression of mGlu5 receptors gives access to programmed cell death in cerebellar granule cells developing in primary cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1460-9568.1998.00230.x
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  • 9
    Digitale Medien
    Digitale Medien
    Effects of Dopaminergic Drugs on Cerebellar Prostaglandin Concentrations (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 41 (1983), S. 0 
    Details
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: Previous data indicate that the injection of dopaminergic drugs induces changes in cerebellar 3′,5′-guanosine monophosphate (cGMP) content. Accordingly, we have investigated the effects of haloperidol, sulpiride, or apomorphine on cerebellar prostaglandin (PG) concentration, a parameter related to cGMP content. Results obtained show that dopamine receptor blocking agents, such as haloperidol and sulpiride, significantly decrease cerebellar PGE2 and PGF2α concentrations, while opposite changes are induced by apomorphine, a dopamine receptor agonist.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1471-4159.1983.tb09072.x
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  • 10
    Digitale Medien
    Digitale Medien
    Spinocerebellar ataxia type 2 in southern Italy: a clinical and molecular study of 30 families (1999)
    Springer
    Journal of neurology 246 (1999), S. 467-471 
    Details
    ISSN: 1432-1459
    Schlagwort(e): Key words SCA2 ; Autosomal ; dominant cerebellar ataxia ; CAG ; expansion ; Intergenerational ; instability ; Anticipation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Autosomal dominant cerebellar ataxia type I is the most common form of dominant ataxia. A genetic heterogeneity has been identified with five different loci (SCA1, 2, 3, 4, and 6). A pathological expansion of a CAG sequence has been identified in SCA1, 2, 3, and 6. We performed molecular analysis in 51 families with autosomal dominant cerebellar ataxia type I, mainly originating from southern Italy and Sicily. Thirty families carry an expanded CAG sequence within SCA2 gene. The mean number of repeats was 39.9 ± 3.3 in 85 expanded alleles, with a range of 34–52. The number of triplets was inversely correlated with age at onset and explained 76% of the variance. The best fit was obtained with an exponential relationship between variables. Expanded alleles were unstable when transmitted from parents to offspring. Expansions were more common than contractions, accounting for 59% of the total meioses and for 80% of the father-child transmissions. The mean intergenerational variation was 1.9 repeats (range –3 to +15) with higher values for male transmissions. Bulbar and autonomic signs were related to disease duration, pyramidal signs to CAG size, cerebellar features and peripheral neuropathy to both. Among the remaining 21 families, three carried the SCA1 and one the SCA6 mutation. This study suggests that SCA2 is the prevalent mutation in southern Italy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004150050385
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