bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corticospinal neurons exhibit a novel pattern of cytoskeletal gene expression after injury
Authors: Mikucki S. A. , Oblinger M. M. 
Published: January 2005

AbstractWe examined changes in the expression of major cytoskeletal protein mRNAs in adult hamster corticospinal neurons after axotomy. While a number of studies had determined that peripheral neurons exhibit major alterations in cytoskeletal gene expression after axotomy, no previous studies had addressed the question of whether or not intrinsic mammalian CNS neurons, which do not have the ability to successfully regenerate axons after injury, alter their expression of tubulin and neurofilament genes after injury. In the present study we used in situ hybridization methods to examine this issue. 35S‐labeled cDNA probe for the low molecular weight neurofilament protein (NF‐L) mRNA and an α‐tubulin mRNA species (Mα1) were used for in situ hybridizations of sections of the sensorimotor cortex obtained 2, 7, and 14 days after unilateral axotomy of the corticospinal tract in the caudal medulla. Film as well as emulsion autoradiography showed dramatic decreases in both α‐tubulin and NF‐L mRNA levels within axotomized neurons in layer Vb of the sensorimotor cortex. Tubulin mRNA levels were decreased as early as 2 days after injury whereas NF‐L mRNA levels were not decreased until later times. Ribosomal RNA (rRNA) levels in axotomized corticospinal neurons were also examined using in situ hybridization with a 35S‐labeled rDNA probe. These studies showed only a slight decrease in rRNA levels in corticospinal neurons at 14 days after axotomy. Immunoblotting experiments of total protein from corticospinal axons in the medulla were performed to assess whether the axonal composition immediately proximal to the injury site reflected changes in cell body gene expression. Both α‐tubulin and NF‐L levels were found to decrease in corticospinal axons by 28 days after injury. These findings, to our knowledge, are the first to demonstrate that a class of mammalian CNS neurons have an intrinsically different cytoskeletal response to axonal injury than do PNS neurons. The failure to up‐regulate tubulin gene expression following injury may contribute to the ineffective regenerative response of these long‐tract CNS neurons.
Biosynthesis and release of tachykinins from rat sensory neurons in culture
Authors: Vedder H. , Otten U. 
Published: January 2005

AbstractA long‐term culture system of dissociated rat dorsal root (DRG) and trigeminal ganglion cells with high cell density has been developed. Two to 3 weeks after plating, the cultures consist of a nearly pure population of sensory neurons, which can be kept for more than 2 months in culture.Cultured neurons synthesize and release the tachykinins substance P (SP) and substance K (SK, neurokinin A) with a time course similar to that observed in vivo. High‐pressure liquid chromatography (HPLC) analysis of peptides extracted from neuronal cultures and synthetic tachykinins revealed identical retention characteristics. Northern blot analysis of mRNAs from cultured cells with a specific tachykinin‐probe demonstrated that the preprotachykinin‐gene is expressed in preparations of both DRG and trigeminal ganglia cells.Depolarizing stimuli such as high potassium (47 mM) evoked a peptide release from cultured neurons in a strictly Ca++‐dependent manner. Capsaicin, a compound known to stimulate nociceptive sensory neurons, dose‐dependently released tachykinins in concentrations as low as 10−9 M. Only total absence of Ca ++ ions from the incubation medium abolished the capsaicin‐induced peptide release. Nifedipine, a blocker of voltage‐dependent L‐type Ca++‐channels, completely blocked the potassium‐induced release of SP but did not reduce the capsaicin‐evoked release.Mediator substances of pain and inflammation, such as bradykinin, serotonin, and histamine, triggered the release of tachykinins from sensory neurons in vitro. These results clearly demonstrate that the neurons characterized express properties similar to those of sensory neurons in vivo and provide model systems for detailed studies of the biosynthesis and release of neuropeptides as well as the participation of sensory neurons in pain and inflammatory reactions.
Myelin basic protein specific T cell lines and clones derived from the CNS of rats with EAE only recognize encephalitogenic epitopes
Authors: Bourdette D. N. , Vainiene M. , Morrison W. , Jones R. , Turner M. J. , Hashim G. A. , Vandenbark A. A. , Offner H. 
Published: January 2005

AbstractThe epitope specificities of myelin basic protein (BP) specific T cell lines derived from the spinal cords (SC) and lymph nodes (LN) of rats with experimental autoimmune encephalomyelitis (EAE) were compared. To induce EAE, Lewis rats were immunized with guinea pig (GP)‐BP and complete Freund's adjuvant. Mononuclear cells from the SC and LN of these animals proliferated in response to BP and the purified protein derivative (PPD) of mycobacterium. After initially being cultured in growth medium, SC mononuclear cells had an enhanced response to BP and lost their response to PPD. LN cells cultured in identical conditions lost their response to both BP and PPD. LN‐derived BP specific cell lines recognized only two epitopes of GP‐BP: an encephalitogenic epitope in residues 72–89 and a non‐encephalitogenic epitope in residues 43–68. SC‐derived BP specific cell lines and clones recognized the 72–89 epitope and a second encephalitogenic epitope contained in residues 87–99 but not the non‐encephalitogenic 43–68 epitope. Unlike those from LN, BP‐specific T cell lines and clones derived from the CNS appear to recognize only encephalitogenic epitopes, including epitopes not recognized by LN lines.
Hyposmolarity‐induced taurine release in cerebellar granule cells is associated with diffusion and not with high‐affinity transport
Authors: Schousboe A. , Olea R. Sánchez , Morán J. , Pasantes‐Morales H. 
Published: January 2005

AbstractThe effects of hyposmotic conditions on taurine uptake and release were studied in mice cultured cerebellar granule cells. The effect of DIDS (4,4′‐diisothiocyanatostilbene‐2,2′‐disulfonate) and of the divalent cations Mg++ and Mn++ on the hyposmolarity‐induced changes in these parameters was investigated. Mg++ (20 mM) and Mn++ (5mM) inhibited by 25% and 41%, respectively, the release of taurine observed in 30% hyposmolar media. DIDS (100 μM) inhibited this release by 46%. Taurine efflux evoked by 50% hyposmolar solutions was reduced about 40% by Mg++ and 55% by Mn++. Taurine uptake into the granule cells could be resolved into a high‐affinity carrier‐mediated component plus a nonsaturable diffusion component. The kinetic constants (Km and Vmax) for the high‐affinity uptake were unaffected by a 50% decrease in the osmolarity. The diffusion constant for the nonsaturable taurine uptake was increased from 1.5 × 10−4 in isosmotic media to 4.6 × 10−4 ml × min−1 mg−1 in hyposmotic (50%) media. This increase in the diffusional component of taurine uptake elicited by the hyposmotic condition was inhibited approximately 25% by either 100 μM DIDS or 5 mM Mn++. These results strongly suggest that the increase in taurine release induced by swelling under hyposmotic conditions is mediated by a diffusional process and not by a reversal of the high‐affinity taurine carrier.
Increase of macrophage colony‐stimulating factor and granulocyte‐macrophage colony‐stimulating factor receptors in the regenerating rat facial nucleus
Authors: Raivich G. , Gehrmann J. , Kreutzberg G. W. 
Published: January 2005

AbstractProliferation of microglial cells commonly occurs in the response of the central nervous system to injury, but little is known about how this process is regulated in vivo. Here we have studied the expression of receptors to macrophage colony‐stimulating factor (MCSF) and granulocyte‐macrophage colony‐stimulating factor (GMCSF) in the normal and regenerating rat facial motor nucleus using receptor immunocytochemistry and in situ ligand binding methods. Under normal conditions, immocytochemical staining with anti‐MCSF receptor (MCSFR) antibody revealed a moderate but selective labelling of microglia‐like cells of the facial motor nucleus. This immunostaining also colocalized with MUC102, a new monoclonal antibody raised against microglial cells in the rat central nervous system. Axotomy of the facial nerve led to a rapid increase in MCSFR‐staining intensity 1 day after injury, which became maximal 7 days postoperatively and then decreased. A similar but somewhat slower increase was also observed for the specific [125I]MCSF binding wiht a maximum at 7 days Specific [125I]GMCSF binding also increased, peaking at 4 days postoperatively and then rapidly decreasing to normal levels at 21 days after axotomy. In summary, axotomy of the facial nerve led to a rapid increase in receptors for MCSF and GMCSF, which coincided with the pattern of microglial proliferation in the regenerating facial motor nucleus. This apparent up‐regulation of receptors for microglial growth factors may play an important role in preparing the microglia to participate in the cellular response to injury in the regenerating central nervous system.
Galactocerebroside and sulfatide independently mediate Ca2+ responses in oligodendrocytes
Authors: Dyer C. A. , Benjamins J. A. 
Published: January 2005

AbstractGalactocerebroside (GalC) and sulfated galactocerebroside (sulfatide) are sphingolipids highly enriched in myelin. The binding of antibodies reactive with either sulfatide Or GalC to cultured Oligodendrocytes causes a Ca2+ influx, followed by microtubule depo lymerization; however, antisulfatide is less effective than anti‐GalC in altering cytoskeleton. Typical Ca2+ responses are delayed for both antibodies but are transient for sulfatide‐reactive antibodies in contrast to the sustained responses previously reported for anti‐GalC (Dyer and Benjamins, J Cell Biol 111:625–633, 1990). Approximately one‐half as many oligodendrocytes respond to sulfatide‐reactive antibodies (about 39%) as to anti‐GalC (about 75%). Subpopulations of Oligodendrocytes were identified that responded to neither antibody, only one antibody, or both antibodies, indicating that sulfatide and GalC independently mediate Ca22+ responses. These results suggest that sulfatide and GalC have different physiologic roles in regulating elaboration of myelin membrane by oligodendrocytes in vivo and support the possibility that viral or immune attack via GalC or sulfatide on oligodendrocytes may mimic normal signals in a manner that disrupts the sequence of events that coordinates myelination or maintenance of myelin in vivo.
Cellular immune crossreactivity between myelin basic protein and synapsin in rats with experimental allergic encephalomyelitis
Authors: De Santis M. L. , Roth G. A. , Cumar F. A. 
Published: January 2005

AbstractWe previously demonstrated that antibodies against myelin basic protein (MBP) obtained from animals with experimental allergic encephalomyclitis (EAE), induced with MBP and purified by affinity chromatography, have the property to recognize a neuronal protein, synapsin Ia and Ib. To investigate whether this Crossreactivity also occurs at the cellular level, we purified spleen and lymph node mononuclear cells from rats sensitized with MBP or synapsin using polystyrene plates coated with the respective antigen. We observed that animals injected with MBP have T lymphocytes that bind both antigens. Using the same system, each purified cell population was confronted again to the studied antigens. The anti‐MBP cells recognized once more epitopes of MBP and about 40% of them also recognized synapsin. On the other hand, cells that first were attached to synapsin, in the second exposure to antigens bound to MBP and synapsin in similar amounts. Double immunofluorescent labeling of the mononuclear cells isolated from animals injected with bovine myelin or MBP showed that the same lymphocyte was able to recognize MBP as well as synapsin. In both experimental systems the quantitative results were similar indicating that in bovine myelin‐ or MBP‐sensitized animals practically all the cells that recognize synapsin are anti‐MBP cells, and of the total cells raised against MBP, around 40% of them show this Crossreactivity. On the contrary, animals injected with synapsin have cells that bind to this protein but not to MBP indicating that the described Crossreactivity, as observed at humoral level, is only in one way. These results suggest that the lymphocytes sensitized against MBP that also recognize synapsin could be of relevance in the pathogenesis of EAE, since neuronal structures arc affected by the immunological response to MBP.
Preparation of a protein‐free total brain white matter lipid fraction: Characterization of liposomes
Authors: Díaz R. S. , Monreal J. , Regueiro P. , Lucas M. 
Published: January 2005

AbstractA method of preparing a total lipid extract (TLE), free of protein, by extracting brain white matter with tetrahydrofuran is presented. The optimal conditions of extraction were found to be 50 ml of THF per gram of lyophilized tissue, though fresh tissue can also be used if larger volumes of solvent are employed. The method allowed, in a short time and in a single step, a yield of TLE of 50% on a dry weight basis. Its analytical characterization revealed a qualitative and quantitative composition very similar to the lipid composition of CNS myelin, including all the phospholipid and galactolipid species, cholesterol and gangliosides, but it contained only traces (0.1%) of protein. TLE has been used to prepare liposomes, either multilamellar (MLVs) or unilamellar (LUVs, SUVs), characterized by freeze ‐fracture electron microscopy. A multilayered, heterogeneous population of liposomes is observed in the MLVs preparation. When these samples were submitted to a freezing and thawing procedure the resulting liposomes were single‐walled, and their intravesicular volume was increased. They were quite impermeable to the mono‐valent cation 86Rb+ and, by contrast rather permeable to 45Ca+ +. Their complex lipid composition, together with their permeability properties and their response to ionophores, make them very useful to study protein‐lipid interactions occurring within the myelin membrane as well as the functional properties of myelin proteins in reconstitution experiments.
Application of a fluorescent dye to study connectivity between third ventricular preoptic area grafts and host hypothalamus
Authors: Silverman R. C. , Gibson M. J. , Silverman A.‐J. 
Published: January 2005

AbstractThe mutant hypogonadal (hpg) mouse lacks a functioning gene for the neurohormone gonadotropin releasing hormone (GnRH). Previous studies from our laboratory had indicated that the initiation and maintenance of reproductive function in these mice could be brought about by the implantation of normal fetal grafts into adult hosts. Testicular or ovarian growth and other indicators of normal neurosecretory output were always accompanied by survival of GnRH neurons andgrowth of GnRH axons into the host median eminence where such axons terminate on the hypophysial portal capillaries. To determine if other connections exist between graft and the host hypothalamus, small crystals of the carbocyanine dye 1,1′‐dioctadecyl‐3,3,3′,3′‐tetramethyl‐indocarbo‐cyanine perchlorate (Dil) were applied to either graft or host after fixation of the brain. Tissue sections were analyzed for retrograde and anterograde movement of the dye. When crystals were placed on the graft, labeled axons were found in the host median eminence or in the host hypothalamus taking an arching trajectory toward the median eminence. Retrogradely labeled neurons in the host were few in number and largely confined to the host arcuate nucleus. With Dil crystals applied to the basal hypothalamus, labeled axons were distributed widely in the host but much sparser in the graft. Axons appeared to enter primarily at sites where the graft and host interface lacked an ependymal lining. Small numbers of retrogradely labeled neurons were also seen in the graft. Most were cells of very simple morphology and were distributed randomly in the graft. When double label experiments were carried out most Dil positive cells in the graft contained GnRH. These results indicate that connectivity between host hypothalamus and the third ventricular preoptic area grafts exists but is limited in nature.
CG‐4, A new bipotential glial cell line from rat brain, is capable of differentiating in vitro into either mature oligodendrocytes or type‐2 astrocytes
Authors: Louis J. C. , Magal E. , Muir D. , Manthorpe M. , Varon S. 
Published: January 2005

AbstractWe have established a permanent cell line (CG‐4) of rat central nervous system glial precursors from primary cultures of bipotential oligodendrocyte‐type 2‐astrocyte (O‐2A) progenitor cells, which were kept proliferating with the mitogen(s) secreted by the neuronal B104 cell line. The CG‐4 cells have a normal karyotype and display the properties of normal O‐2A cells. CG‐4 cells can be propagated in serum‐free culture medium supplemented with medium conditioned by B104 cells for unrestricted periods of time as O‐2A cells, characterized by the presence of the A2B5 surface marker and the absence of markers specific for Oligodendrocytes (galactocerebroside, myelin basic protein) or type 2‐astrocytes (glial acidic fibrillary protein). bFGF and PDGF are potent mitogens for CG‐4 cells and their combination can substitute for the B104‐derived mitogen(s). CG‐4 cells are capable of differentiating into either Oligodendrocytes or type 2‐astrocytes. Differentiation into Oligodendrocytes occurs after withdrawal of the mitogen. Replacement of the mitogen with fetal calf serum (20%), in contrast, induces 50% of the CG‐4 cells to differentiate into type 2‐astrocytes. Pure cultures of Oligodendrocytes or type 2‐astrocytes can be generated in substantial amounts from CG‐4 cells and maintained for several weeks in medium containing 5% fetal calf serum.
Coexistence of cholinergic, catecholaminergic, serotonergic, and glutamatergic neurotransmitter markers in mouse clonal hybrid neurons derived from the septal region
Authors: Satoh Jun‐ichi , Gallyas F. , Endoh M. , Yamamura T. , Kunishita T. , Tabira T. 
Published: January 2005

AbstractTwo clonal immortalized neurons designated SN6.1b and SN6.2a were isolated by limiting dilution from a mouse embryonic septal cholinergic neuronal hybrid cell line SN6 (Hammond et al., 1986). In the serum‐containing medium without extra differentiating agents, one‐third of SN6.1b cells stably exhibited a morphology of differentiated neurons with extensive elaborate neurites, while a majority of SN6.2a cells, along with the parent cell line SN6, were round in shape with poorly branched short processes. Neurochemical studies showed that both clones synthesized choline acetyltransferase (ChAT), dopamine, norepinephrine, serotonin, and glutamate. Immunocytochemically, they expressed a number of neuronal antigens, such as 200‐kDa neurofilament protein, neuron‐specific enolase, microtubule‐associated protein 2, tau protein, tubulin, neural cell adhesion molecule, Thy‐1.2, saxitoxin‐binding sodium channel protein, ChAT, tyrosine hydroxylase, serotonin, and glutamate. The coexistence of cholinergic, catecholaminergic, serotonergic, and glutamatergic neurotransmitter markers in the clonal hybrid septal neurons that express a variety of immunocytochemical properties of differentiated neurons suggests that embryonic septal cholinergic neurons are potentially multiphenotypic with respect to neurotransmitter synthesis. © 1992 Wiley‐Liss, Inc.
Dibutyryl cyclic AMP stimulates expression of ependymin mRNA and the synthesis and release of the protein into the culture medium by neuroblastoma cells (NB2a/d1)
Authors: Shashoua Victor E. , Nolan P. M. , Shea T. B. , Milinazzo B. 
Published: January 2005

AbstractNorthern blot, immunoprecipitation, and gel electrophoretic data demonstrate that the mouse neuroblastoma NB2a/d1 cells express ependymin mRNA and synthesize and release into the culture medium a protein with immunoreactivity and electrophoretic mobility properties identical to ependymin. This is a brain extracellular glycoprotein that has been implicated in the consolidation process of memory formation and neuronal regeneration. In labeling experiments with 35S‐methionine, dibutyrylcyclic3′,5′‐adenosine‐monophosphate (dbcAMP) was found to stimulate the expression of ependymin mRNA and the enhanced synthesis and release of ependymin into the culture medium at the same time that dbcAMP stimulation of neurite outgrowth takes place. These results are consistent with the proposed role of the protein in the mechanism of neuronal regeneration and synaptogenesis. The data indicate that the NB2a/d1 cell line is a good model system for studies of the functional properties of ependymin. © 1992 Wiley‐Liss, Inc.
Effect of dark rearing on the volume of visual cortex (areas 17 and 18) and number of visual cortical cells in young kittens
Authors: Takács József , Saillour P. , Imbert M. , Bogner M. , Hámori J. 
Published: January 2005

AbstractThe surface area, total volume, and total number of neurons of areas 17 and 18 in one hemisphere of dark‐reared (DR), dark‐reared and light‐exposed (DRL), and normally reared (NR) kittens were studied at the age of 6 weeks. The thickness of the visual cortex was lower by 13% and 11% (area 17) and by 17% and 16% (area 18) in DR and DRL groups, respectively, when compared with similar cortical areas in NR kittens. The surface area values of area 17 were nearly the same in DR and DRL kittens, both being, however, 37% smaller than in NR animals. The surface area of area 18 was significantly smaller than that of area 17 in each group, and was also lower in DR (by 27%) and DRL (by 21%) groups when compared with the NR group. As a consequence of dark rearing, the numerical density of cortical neurons in area 17 amounted to about double of the value observed in normally reared kittens and was also significantly higher in area 18. The numerical density of nerve cells of DRL kittens fell between the DR and NR groups. The total cortical volume of area 17 was similar in DR and DRL groups but it was by 46% (DR) and by 44% (DRL) smaller than in NR Kittens. In each experimental group, the total volume of area 18 was significantly smaller than that of area 17. The cortical volume of area 18 was also smaller than in the NR group by 39% and 34% in DR and DRL groups, respectively. In DR and NR kittens, the total numbers of neurons in areas 17 (DR =; 26.4 million, NR =; 25.7 million) and 18 (DR =; 8.5 million, NR =; 9.0 million) were essentially similar. In the DRL groups a significantly smaller number of cortical neurons was found both in area 17 (21.5 million) and in area 18 (6.8 million). It is concluded that, in spite of considerable differences in the cortical thickness, surface area, numerical density, and total cortical volume, the absolute numbers of neurons in area 17 and 18 of visually deprived (DR) and NR kittens do not differ at 6 weeks of age. The main deficit in cortical organization following dark rearing, therefore, appears to be confined mainly to the neuropil, as a result of an underdevelopment of neuronal processes and of depressed synaptic organization. The significant decrease of the total cortical cell number both in areas 17 and 18 in the DRL group, in which dark rearing was followed by a brief exposure to light, is apparently the consequence of a rapid cell loss in the visual cortex. © 1992 Wiley‐Liss, Inc.