摘要:

AbstractChick sympathetic neurons (E‐9) are capable of moving on a laminin substrate but not on more adhesive substrates in vitro. The effect of laminin is dose‐dependent and reduced by the addition of anti‐laminin antibodies, whereas soluble laminin does not stimulate movement. The onset of neuronal movement is preceded by, and highly correlated with, the onset of neurite formation. The addition of 1,2 dioctanoyl‐snglycerol (DAG), a stimulator or protein kinase C that has been shown to inhibit neurite outgrowth, was found to delay both process formation and neuronal movement but did not affect the correlation between these two measures. These results support the conclusion that laminin stimulates primary neuronal movement in vitro and suggest that the mechanism underlying movement involves process formation followed by “towing” of the cell body by the advancing process. The similarities of this in vitro behavior to that observed in vivo suggest that similar mechanisms may underlie neuronal movement in the developing nervous system as suggested by Morest (Z Anat Entwicklungsgesch130:265–305, 1970) and Liesi (EMBO J4:1163–1170, 1985;Exp Neurol117:103–113, 1992). © 19

ISSN:0360-4012    

DOI:10.1002/jnr.490360602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractMyelin deposition and maintenance are critical to proper function of the mammalian nervous system. Previous investigations of myelination in the central nervous system (CNS) were hampered by the lack of an in vitro system that can faithfully reproduce in vivo events yet is amenable to biochemical investigation. We have developed a procedure, based on organotypic cultures, which permits efficient preparation of large numbers of cerebellar slice cultures that can be easily manipulated. Cultures have been examined to document myelination biochemically (by incorporation of [35S] sulfate into sulfolipids), immunohistochemically (by labeling the myelin components myelin basic protein and galactocerebroside), and morphologically (by both light and electron microscopy). We tested the effects of biologically active peptides and antibodies on myelination in the thin slices. The results indicate that the cultures provide an in vitro system that can be used to examine specific cellular events that occur during CNS myelination. © 1993 Wiley‐Liss, I

ISSN:0360-4012    

DOI:10.1002/jnr.490360603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractWe report here on the synthesis and characterization of a fully active biotinylated derivative of the botulinum neurotoxin type A. Different ratios of biotin:botulinum toxin were tested to optimize derivatizing conditions and a ratio of 35:1 was selected for further experiments. The average number of biotin groups per toxin molecule was estimated to be 7.8, occurring at both heavy and light chains, and almost all externally located and easily accessible to recognition by streptavidin. The modified toxin retained its toxicity and its ability to interact with biological membranes. Apart from its suitability for detection in Western blots and in microtiter well plates, biotinylated botulinum toxin proved to be adequate for morphological labeling studies at both light and electron microscopy. Peroxidase histochemistry in cryostat sections of intoxicated rat hemidiaphragm muscles showed a distinct labeling of end‐plates. Electron microscopy studies were performed on the electric organ ofTorpedo marmoratausing colloidal gold‐conjugated streptavidin for detection. After intoxication of electric organ fragments with the modified toxin, gold labels were found associated with the presynaptic plasma membrane of nerve terminals and with the membrane of synaptic vesicles. Moreover, the distribution of biotinylated botulinum toxin binding sites over the membrane of synaptosomes isolated from the electric organ ofTorpedoand their relationship with intramembrane particles were analyzed using the replica‐staining label‐fracture technique. It was found that the toxin is never associated with intramembrane particles. © 1993 Wiley

ISSN:0360-4012    

DOI:10.1002/jnr.490360604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractFour types of cells, RT4‐AC (stem cell type), RT4‐B and RT4‐E (neuronal cell types), and RT4‐D (glial cell type) were previously isolated from an ethylnitrosourea (ENU) induced rat peripheral neurotumor RT4. In a phenomenon termed cell‐type conversion, RT4‐AC spontaneously and permanently gives rise to the three other cell types in culture. In the RT4 system the expression of glial fibrillary acidic protein (GFAP) and S100β protein genes segregates in a celltype specific manner. To further characterize the RT4 family, the expression of four myelin‐forming glial genes—P0 glycoprotein, suppressed cAMP inducible POU (SCIP), 2′, 3′‐cyclic nucleotide 3′‐phosphodiesterase (CNP), and myelin basic protein (MBP)—has been studied in the RT4 cell lines. In addition to these genes, the expression of the lowaffinity nerve growth factor (LNGF) receptor (expressed in immature Schwann cells) has been examined. We have found the following results. (1) The stem cell type RT4‐AC and the glial cell type RT4‐D express mRNA transcripts of P0, SCIP, and CNP (the larger form, 2.8 kb), and the amount of mRNA of these genes was increased by forskolin. (2) RT4‐AC and RT4‐D also express a low level of MBP mRNA upon forskolin treatment. (3) The neuronal cell types RT4‐B and RT4‐E do not express any of these myelinforming glial genes with or without forskolin treatment. (4) The LNGF receptor mRNA is expressed in RT4‐AC and RT4‐D and at a lower level in RT4‐B; its expression is s

ISSN:0360-4012    

DOI:10.1002/jnr.490360605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractSmall antimicrobial peptides are abundantly produced by leukocytes. These peptides are active against a broad range of pathogens, notably bacteria, fungi, and enveloped viruses, but hardly anything is known about their physiological and pathophysiological relevance.We observed that bactenecin, a dodecapeptide, is strongly cytotoxic ro rat embryonic neurons, fetal rat astrocytes and human gliblastoma cells. This neurotoxicity is unique to bactenecin, as a panel of antibacterial peptides from vertebrates and invertebrates, like defensins, corticostatin, indolicidin, ceropin P1, tachyplesin I, the magainings, or apidaecins did not impair neuronal viability. © 1993 Wiley‐Liss, I

ISSN:0360-4012    

DOI:10.1002/jnr.490360606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe survival and functional maintenance of spinal motoneurons, both during the period of developmental cell death and in adulthood, have been shown to be dependent on trophic factors. In vitro experiments have previously been used to identify several survival factors for motoneurons, including CNTF, LIF, and members of the neurotrophin, FGF, and IGF gene families. Some of these factors have also been shown to be active in vivo, either on chick motoneurons during embryonic development or on lesioned facial and spinal motoneurons of the newborn rat. Here we demonstrate that lesioned newborn rat facial motoneurons can be rescued by NT‐4/5, IGF‐I and LIF. Furthermore, in contrast to chick motoneurons, the survival of isolated embryonic rat motoneurons can be maintained by the neurotrophins BDNF, NT‐3, and NT‐4/5. IGF‐I and FGF‐5 were also active in this system, each supporting more than 50% of the originally plated neurons. The responsiveness of motoneurons to multiple factors in vitro and in vivo suggests that motoneuron survival and function are regulated by the coordinated actions of members of different gene families. © 1993 Wil

ISSN:0360-4012    

DOI:10.1002/jnr.490360607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractWe have investigated the effect of basic fibroblast growth factor (bFGF) on the proliferation and phenotype of differentiated oligodendroglia. Using primary cell cultures enriched in oligodendrocytes but containing few O2A‐oligodendrocyte progenitor cells, we demonstrate that bFGF treatment greatly increases the proportion of 02A cells while decreasing the proportion of galactocerebroside+(GalC+), myelin basic protein+(MBP+) oligodendrocytes, and the steady state levels of MPB mRNA. Complement mediated cell lysis experiments using the A2B5 antibody to deplete existing O2A cells or the R‐Mab antibody to deplete existing oligodendroglia show that bFGF elicits a rapid increse in the number of O2A cells in cultures previously depleted of O2A cells, but does not cause an early incrase in O2A cells in cultures from which oligodendroglia had been removed, indication that the oligodendrocytes are the source of the newly recruited O2A cells. This bFGF‐mediated transition from oligodendrocyte to O2A cells occurs with a time course similar to the bFGF‐induced incrase of the proliferation rate of the GalC+oligo‐dendrocvtes. Studies with purified, passaged cells of the oligodendroglial lineage show that bFGF augmenta oligodendroglial dedifferntiation and proliferation in chronologically adult oligodendrocytes and in the virtual absence of other cell types. We have thusdemonstrated that mature oligodendrocytes are induced by bFGF to dedifferentiate and proliferate, suggesting a mechanism for regeneration of the oligodendroglial lineage following demyelinating disease. © 1993 Wiley

ISSN:0360-4012    

DOI:10.1002/jnr.490360608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractReactive microglia and invading macrophages, Which appear in brain damaged by stroke or trauma, secrete neuron‐killing factors. This release of cytotoxic substances is a delayed process and is not detected until inflammatory cells reach a peak of reactivity by the second day after injury. Proximity to the site of injury and density of mononuclear phagocytes determine in part the amount of neurotoxic activity released by injured tissues. Moreover, drugs that suppress the accumulation of reactive microglia and macrophages also reduce tissue production of neuron poisons. Neurotoxins released by brain inflammatory cells or extracted directly from inflamed tissues are heat‐stable, protease‐resistant molecules<500 daltons with actions blocked by N‐methyl‐D‐aspartate (NMDA) receptor antagonists. These molecules are distinguished from free radical intermediates, bind to cation exchange resins, lack carboxyl moieties, and are separated from excitatory amino acids including glutamate or aspartate and from the NMDA receptor‐mediated toxin quinolinc acid by ion exchange and reverse phase chromatography. Our data suggest that an unrecognized class of neuron‐killing molecules produced by inflammatory cells mediate the delayed neuronal loss associated with stroke and trauma. © 1993

ISSN:0360-4012    

DOI:10.1002/jnr.490360609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

ISSN:0360-4012    

DOI:10.1002/jnr.490360613

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY