bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of vimentin by cultured astroglia and oligodendroglia
Authors: Meyer S. A. , Ingraham C. A. , McCarthy K. D. 
Published: January 2005

AbstractThe objective of this study was to determine whether vimentin expression by process‐bearing astroglia and oligodendroglia cultured from neonatal rat cerebral cortex resembled that in brain where vimentin is common in immature astroglia and a few subpopulations of mature astroglia, but is absent in oligodendroglia. Vimentin expression was detected by immunofluorescence microscopy using a monoclonal antibody (V9) against porcine lens vimentin in combination with either antiserum against the astroglial marker, glial fibrillary acidic protein (GFAP), or with antiserum against the oligodendroglial marker, galactocerebroside (GC). Specificity of the antivimentin antibody was indicated on immunoblots of process‐bearing cell proteins separated by two‐dimensional polyacrylamide gel electrophoresis. Enrichment of cultures for either GFAP+ astroglia or GC+ oligodendroglia was achieved by supplementation of the culture medium with fetal calf serum at 10% or 0.5%, respectively. Process‐bearing cells maintained in 10% serum exhibited heterogeneity in their expression of GFAP and vimentin. Approximately half of the cells were GFAP+/vimentin+ throughout the 2‐week culture period examined. GFAP+/vimentin− cells were a minor population at early times (3–4 days) in culture, but accounted for 40% of process‐bearing cells after 2 weeks. Cultures maintained in reduced (0.5%) serum and stained for GC and vimentin also exhibited heterogeneity. Both GC+/vimentin+ and GC+/vimentin− cells were observed, with vimentin+ cells composing two‐thirds and one‐half of the GC+ population after 3 and 6 days, respectively, in reduced serum. The high incidence of vimentin expression by process‐bearing astroglia and oligodendroglia suggests that these cultures contain glia in a relatively early stage of development. The decrease in vimentin expression with time in culture suggests that the specific developmental processes which lead to a reduction in vimentin in brain during maturation may be exhibited by process‐bearing glia in vitro.
Chelation of endogenous membrane calcium inhibits γ‐aminobutyric acid uptake in synaptosomes
Authors: Tapia R. , Salazar C. 
Published: January 2005

AbstractIn a previous work, we have demonstrated that calcium chelators induce the release of γ‐aminobutyric acid (GABA) from synaptosomes in a Na+ ‐dependent manner and that this release is blocked by cations such as Mg2+, La3+, and ruthenium red. In the present study, we show that treatment of synaptosomes with 0.1 mM EGTA in the absence of both Ca2+ and Mg2+ inhibits the sodium‐dependent high‐affinity uptake of [3H]GABA by about 50%. This inhibition increased to about 65% with 1.5 mM EGTA, and it was completely prevented by an excess of Ca2+ or by 1.2 mM Mg2+. In contrast, when EDTA was used as a chelator, Mg2+ was unable to reverse the inhibition. The inhibitory effect of 0.1 mM EGTA was also prevented by 250 μM La3+ or by 20 μM ruthenium red. In the absence of chelators and the presence of Ca2+ and Mg2+, 50 μM and 200 μM La3+ inhibited GABA uptake by about 20 and 50%, respectively, whereas 20 μM ruthenium red produced a nonsignificant 25% inhibition and nifedipine was without effect. It is concluded that the membranesurface negative charges, probably those of the sialic acid molecules that have been implicated in the functioning of the GABA carrier, must be neutralized by endogenous Ca2+ or by another cation in order to permit the adequate function of the transporter. The inhibition by La3+ in the absence of the chelators could be explained by a binding of this cation to the Na+ sites on the GABA carrier.
Differential control of tryptophan hydroxylase expression in raphe and in pineal gland: Evidence for a role of translation efficiency
Authors: Dumas S. , Darmon M. C. , Delort J. , Mallet J. 
Published: January 2005

AbstractIn a previous study, we characterized two tryptophan hydroxylase mRNAs (TPH mRNAs) in the pineal gland. However, we failed to detect these species in the raphe by Northern blot experiments. Here, we report by S1 nuclease analysis and in situ hybridization that these two TPH mRNAs, as well as a third species, are expressed both in pineal gland and in raphe. In both tissues, the three mRNAs are transcribed predominantly from the same promoter. Strikingly, from the results of S1 maping analysis, it was observed that the total level of TPH mRNA per tissue is at least 150 times lower in the raphe than in the pineal gland. In contrast, TPH antigen as quantified by immunoblot experiments is about threefold more abundant per raphe than per pineal gland. TPH mRNA from one raphe and one pineal gland yield in vitro about the same amount of TPH antigen, suggesting that the discrepancy in the ratios of TPH mRNA and TPH antigen between the raphe and the pineal gland results, at least in part, from a difference in the translation efficiency of TPH mRNAs in the two structures.
Development of neurophysin‐containing neurons in primary cultures of rat hypothalami is related to the age of the embryo: Morphological study and comparison of in vivo and in vitro neurophysins, oxytocin, and vasopressin content
Authors: Di Scala‐Guenot D. , Strosser M. T. , Sarlieve L. L. , Legros J. J. , Richard P. 
Published: January 2005

AbstractThe morphological development of immunocytochemically identified neurophysin neurons and the evolution of neuropeptide content (neurophysins, vasopressin, and oxytocin) were studied in primary cultures of hypothalami obtained from 15‐to 19‐day‐old embryos. According to their perikaryal surface, two populations of neurons were distinguished: large and small cells. Full development (defined by the perikaryal surface) of these neurons was reached at day 21 only in cultures from 15‐ or 16‐day‐old embryos. These two types of neurons may correspond to the magnocellular and parvocellular neurons described in vivo. Total neurophysins, vasopressin, and oxytocin content were measured by specific radioimmunoassays. Ontogeny of neurophysins and vasopressin showed a good correlation between cells cultured from 15‐ to 16‐day‐old embryos and hypothalami from age‐matched rats. However, oxytocin was never detected in any of the cultures whatever the age of the embryos. Under our experimental conditions, hypothalamic primary cultures from 15‐ to 16‐day‐old embryos therefore appeared to be suitable for studying the differentiation and regulation of neurophysin‐and vasopressin‐containing neurons.
Coupling of glutamatergic receptors to changes in intracellular Ca2+ in rat cerebellar granule cells in primary culture
Authors: Holopainen I. , Louve M. , Enkvist M. O. K. , Akerman K. E. O. 
Published: January 2005

AbstractChanges in cytosolic free Ca2+ concentrations, [Ca2+]i, in response to glutamate and glutamate receptor agonists were measured in rat cerebellar granule cells grown on coverlips. The intracellular Ca2+ as measured with fura‐2increased by applying kainate, N‐methyl‐D‐aspartate (NMDA), quisqualate, and (RS)‐d‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐propionic (AMPA). When the extracellular Mg2+ was removed, the effects of NMDA and the NMDA receptor agonist cis‐(±)‐1‐amino‐1,3‐cyclopentanedicarboxylic acid (cis‐ACPD) ON intracellular Ca2+ were augmented. Glycine potentiated the effects of NMDA and cis‐ACPD if the membrane was depolarized by increasing the extracellular K+ concentration. The NMDA receptor antagonist DL‐2‐AMONO‐5‐phosphonopentanoic acid (AP5) abolished and the antagonist 3‐([±]‐2‐carboxypiperazin‐4‐yl)propyl‐1‐phosphonic acid (CPP) greatly reduced the effect of NMDA in both the normal and the Mg‐free media. The dose‐ response curves of NMDA and, to a lesser extent, of kainate were shifted to the left, and that of quisqualate became biphasic in the Mg‐free medium. The increase in [Ca2+]i produced by high quisqualate concentrations in the Mg‐free medium was totally abolished by AP5. The results suggest that Ca2+ influx in cerebellar granule cells occurs through both NMDA‐ and non‐NMDA‐Coupled ion channels. A part of the quisqualate‐induced rise in cytosolic Ca2+ seems to be linked to the activation of NMDA recptors.
Bilateral recovery of striatal dopamine after unilateral adrenal grafting into the striatum of the 1‐methyl‐4‐(2′methylphenyl)‐1,2,3,6‐tetrahydropyridine (2′CH3‐MPTP)‐treated mouse
Authors: Bohn M. Churchill , Kanuicki M. 
Published: January 2005

AbstractA rodent model of Parkinson's disease, the 1‐methyl‐4‐(2′methylphenyl)‐1,2,3,6‐tetrahydropyridine treated mouse, was used to determine whether striatal dopamine levels recover following grafting adrenal medulla into the striatum. Four types of grafts were performed: (1) adult mouse adrenal medulla, (2) adult adrenal medulla that had been freeze‐thawed to kill viable cells, (3) postnatal day 7 adrenal medulla, and (4) sham grafts lacking tissue. At 1 month after grafting, only postnatal day 7 grafts contained surviving cells. However, all three types of tissue grafts promoted a unilateral recovery of host dopaminergic fibers on the side of the graft. In striking contrast to the unilateral recovery of the dopaminergic fibers, striatal dopamine levels were increased bilaterally in all tissue grafted mice. These observations suggest that adrenal tissue grafted into the striatum, whether it remains viable or not, has more widespread biochemical effects on the host dopaminergic system than previously recognized. Moreover, these observations bear on mechanisms that may underlie the general recovery of motor disturbances reported in human Parkinson's disease patients who have received a striatal graft of adrenal tissue.
Identification and isolation of an axonal plasma membrance enriched fraction from cerebellar granule cell neurites
Authors: Mason P. W. , Russell T. L. , DeVries G. H. 
Published: January 2005

AbstractA procedure is described to isolate a fraction enriched in cerebellar granule cell neuritic membranes. Morphological markers that are specific for either the granule cell perikarya or neuritic membranes have been identified. Concanavalin A (Con A) has been shown to bind predominantly to the granule cell neurites whereas, the enzymes acetylcholinesterase (AChE) and 2′,3′, cyclic nucleotide‐3‐phosphohydrolase (CNPase) are localized predominantly in the neuronal cell bodies. The membrane fraction enriched in Con A binding has been used to generate a monoclonal antibody which morphologically recognized the cerebellar granule cell nueritic membrance. Following fractionation of the granule cells, each marker was used to identify the cellular origin of the fractions. The neuritic markers Con A and the neuritic membrane antibody MR2 bound predominately to membrances found in the 29.1% and 31.5% region of the sucrose gradient. The perikaryal markers, CNPase and AChE activity were most enriched in membrance fractions found at a sucrose concentration of 23% and 21%, respectively. Morphological examination of the neuritic enriched fraction shows that it contains predominately membranous material with few subcellular organelles. The protein profiles of the cerebellar granule cell fractions are unique when compared with the protein profiles of other neuronal and non‐neuronal fractions. The membrane fraction isolated from the cerebellar granule cells should prove useful in furthering our understanding of the axonal influence on glial development.
Neuroplasticity in the olfactory system: Differential effects of central and peripheral lesions of the primary olfactory pathway on the expression of B‐50/GAP43 and the olfactory marker protein
Authors: Verhaagen J. , Oestreicher A. B. , Grillo M. , Khew‐Goodall Y.‐S. , Gispen W. H. , Margolis F. L. 
Published: January 2005

AbstractThe regeneration of the olfactory neuroepithelium following olfactory bulbectomy or peripheral deafferentation was studied with mRNA probes and antibodies for B‐50/GAP43 and for olfactory marker protein (OMP). Two stages in the regeneration of the olfactory epithelium could be discerned with these reagents. The first stage occurs following either peripheral deafferentation of the olfactory epithelium with Triton X‐100 (TX‐100) or after bulbectomy and is characterized by the formation of a large population of immature olfactory receptor neurons. These newly formed neurons express B‐50/GAP43, a phosphoprotein related to neuronal growth and plasticity. During the second stage of the regeneration process the newly formed olfactory neurons mature, as evidenced by a decrease in their expression of B‐50/GAP43 and an increase in the expression of OMP. This stage is only manifested if the developing neurons have access to the target olfactory bulb. Formation of a full complement of OMP‐expressing neurons occurs only after peripheral lesion with TX‐100. In contrast, following bulbectomy the reconstituted olfactory epithelium lacks its normal target and is compromised in its ability to recover from nerve damage, as evidenced by the presence of a large number of B‐50/GAP43‐expressing neurons up to 3 months after the lesion and its failure to establish a full complement of OMP‐expressing neurons. These results demonstrate that the olfactory epithelium is capable of replacing its sensory neurons independently of the presence of its target, the olfactory bulb. However, the differential patterns of expression of B‐50/GAP43 and OMP at long times after peripheral lesion with TX‐100 or bulbectomy illustrate the profound effect the olfactory bulb has on neuronal maturation in reconstituted olfactory neuroepithelium.
Acute and persistent varicella‐zoster virus infection of human and murine neuroblastoma cell lines
Authors: Bourdon‐Wouters C. , Merville‐Louis M.‐P. , Sadzot‐Delvaux C. , Marc P. , Piette J. , Delrée P. , Moonen G. , Rentier B. 
Published: January 2005

AbstractHuman and murine neuroblastoma cell lines were infected in vitro with varicella‐zoster virus (VZV). Infected human neuroblastoma cells (IMR‐32) supported the synthesis of abundant viral antigens as detected by indirect immunoperoxidase labeling using human serum rich in anti‐VZV antibodies and did not survive the infection. In situ hybridization (ISH) with VZV‐cloned probes revealed a strong hybridization signal in these infected cells. During cultivation, the virus was released in the culture medium, and viral polypeptides were revealed by Western blotting of infected cells, using either a monoclonal anti‐gpI antibody or a rabbit antiserum. All these findings indicate that IMR‐32 cells support a productive and lytic infection by VZV, whether infected by cell‐free virus or by cocultivation with infected cells. Murine neuroblastoma cells (neuro‐2A) survived VZV infection and did not produce any infectious virus. No VZV‐specific proteins were detected in infected cells either by immunolabeling or by Western blotting. However, viral nucleic acids could be detected by ISH, indicating that mouse neuroblastoma cells displayed a nonproductive, nonlytic infection. Infected neuro‐2A cells have been examined by ISH using probes corresponding to immediate early (IE) genes 4, 62, and 63 and late (L) gene 31 encoding gpII. A strong hybridization signal was detected when infected cells were probed with a fragment containing the IE genes 62 and 63. Lower levels of hybridization were detected with the other probes, corresponding to IE or L genes. These systems allow comparative molecular analysis of persistent and acute infection of nerve cells by VZV.
The epileptogenic action of the taurine analogue guanidinoethane sulfonate may be caused by a blockade of GABA receptors
Authors: Herranz A. S. , Solis J. M. , Herreras O. , Menéndez N. , Ambrosio E. , Orensanz L. M. , del Rio R. Martin 
Published: January 2005

AbstractThe aim of this paper is to clarify the mechanism through which the taurine analogue guanidinoethane sulfonate (GES) produces its epileptogenic effects. Experiments were performed in the rat hippocampus in vivo, using a brain dialysis probe also containing a recording electrode. Perfusion of 10 mM GES induced an enhancement of extracellular taurine levels probably as a result of forced efflux through the taurine uptake systems in a heteroexchange process. This taurine increase was highly reversible. GES also induced an increase of neuronal excitability and an impairment of recurrent inhibition as judged by the neuronal pattern discharge of evoked potentials. These results indicate the possible implication of GABA receptors in the epileptogenic effect of GES. Specific binding of [3H]‐GABA to P2 fractions was inhibited by both bicuculline methiodide (BMI) and GES with the same potency. Similar results were obtained using cerebral sections. Autoradiographic experiments confirm the binding results. GES and BMI completely displaced [3H]‐GABA binding. All these results suggest that the epileptogenic GES action is due to a direct antagonism on GABAA receptors.
Establishment of permanent astroglial cell lines, able to differentiate in vitro, from transgenic mice carrying the polyoma virus large T gene: An alternative approach to brain cell immortalization
Authors: Galiana E. , Borde I. , Marin P. , Rassoulzadegan M. , Cuzin F. , Gros F. , Rouget P. , Evrard C. 
Published: January 2005

AbstractPermanent untransformed cell lines have been established from the cerebral cortex of transgenic mice that carry the polyoma virus large T gene. The immortalized cells described here synthesize laminin and neural cell adhesion molecules and induce primary neurons to develop neuritic processes. As shown by immunofluorescence and immunoblotting assays, they begin to synthesize the glial fibrillary acidic protein (GFAP) after confluence. Double labelling experiments indicated that GFAP expression is reversibly correlated with the arrest of cell division. The present cells also display adrenergic, serotoninergic, and high levels of muscarinic receptors coupled to the phosphatidylinositol signalling pathway. Taken together, our data show that these cell lines constitute homogeneous cell material that has retained the main differentiative, functional, and growth properties of normal astrocytes. Therefore, such clonal untransformed cell lines should be useful for further molecular studies, addressing terminal differentiation of glial cells, glioneuronal interactions, and astroglial expression of receptors for neurotransmitters. Furthermore, we suggest that this approach of cell immortalization by the use of transgenic mice carrying a non‐transforming oncogene might be extended to a variety of cell types.
Nerve growth factor and K‐252a increase catecholamine release from PC12 cells
Authors: Nikodijevic B. , Creveling C. R. , Koizumi S. , Guroff G. 
Published: January 2005

AbstractPC12 cells are a nerve growth factor‐responsive clone derived from a rat pheochromocytoma. The cells contain catecholamines and secrete them in response to depolarizing stimuli and cholinergic agonists. Treatment of the cells with nerve growth factor produces a number of very rapid changes, including the structural rearrangement of the cell membrane, the generation of a number of different second messengers, and the phosphorylation of several proteins. The present studies show that nerve growth factor treatment increases the release of dopamine and norepinephrine from the cells within a few minutes and does so independently of its effect on their metabolism. The experiments indicate that this effect on nerve growth factor is dependent on the presence of extra‐cellular calcium and can be blocked by calcium channel antagonists. K‐252a, an alkaloid‐like material, usually found to inhibit the actions of nerve growth factor on PC12 cells, also increases the release of cat‐echolamines under these conditions.
Evidence for the colocalization of the axonal mitogen for Schwann cells and oligodendrocytes
Authors: Mason P. W. , Chen S. J. , De Vries G. H. 
Published: January 2005

AbstractAxons that normally will encounter either CNS or PNS glia have been shown to contain a powerful mitogen for both Schwann cells and oligodendrocytes. The normally nonmyelinated, nonglial ensheathed cerebellar granule cells have been shown to possess a proliferative signal for Schwann cells, suggesting that a glial mitogen is common to all axons. To determine if a glial mitogen capable of stimulating both Schwann cells and oligodendrocytes is colocalized on all types of axons we have (1) cocultured granule cells with oligodedrocytes, (2) incubated oligodendrocytes with granule cell membranes, and (3) evaluated the ability of heparin extracts of granule cell membranes, splenic nerve microsomes, and axolemmaenriched fractions isolated from rat and bovine CNS to stimulate mitosis of cultured oligodendrocytes. Neither the intact granule cells nor the granule cell membrane fraction stimulated cultured oligodendrocytes to divide. However, heparin extracts of the granule cell membranes were significantly mitogenic to the cultured oligodendrocytes. Heparin extracts of splenic nerve microsomes were more mitogenic than the comparable extract obtained from bovine CNS axolemma‐enriched fractions. These results suggest that the neuronal mitogen for oligodendroglia is co‐localized with the neuronal mitogen for Schwann cells.
Structural changes in astrocytes induced by seizures in a model of temporal lobe epilepsy
Authors: Castiglioni A. J. , Peterson S. L. , Sanabria E. L. , Tiffany‐Castiglioni E. 
Published: January 2005

AbstractInjection of iron‐chloride solution unilaterally into the hippocampus of albino rats induced transient seizure activity which lasted approximately 2 weeks. Frontal and parietal cortices of experimental rats, control rats which received NaCl injections, and unoperated normal rats were compared by means of a Golgi stain which demonstrated astrocytes and their processes in their entirety. Morphometric analysis showed that cortical astrocytes of rats having intermittent seizure activity over a prolonged period were significantly larger than cortical astrocytes of control rats. These findings indicate that seizure activity causes structural brain changes at anatomical sites distant from the hippocampal seizure focus. Similar phenomena may contribute to the development of psychiatric and neurological changes in the epileptic patient.
In vivo labeling of phencyclidine (PCP) receptors with 3H‐TCP in the mouse brain
Authors: Maurice T. , Vignon J. 
Published: January 2005

AbstractThe phencyclidine (PCP) derivative N‐[1‐(2‐thienyl) cyclohexyl]‐piperidine (3H‐TCP) was used to label in vivo the N‐methyl‐D‐aspartate (NMDA) receptor‐associated ionic channel in the mouse brain. After the injection of a tracer dose of 3H‐TCP, a spread labeling throughout the brain was observed, but was the highest in the cerebellum. Preadministration of unlabeled TCP (30 mg/kg) resulted in a 90% reduction of 3H‐TCP binding. PCP, TCP, MK‐801, dexoxadrol, ketamine, and SKF 10,047 isomers dose‐dependently prevented the in vivo 3H‐TCP binding. ID50 determined in the cerebrum and the cerebellum were respectively correlated with K0.5 for 3H‐TCP high (rat cortex) and low affinity (rat cerebellum) sites in vitro. The pharmacological specificity of the 3H‐TCP binding site in the cerebellum was significantly different from that in the cerebrum. ID50 values were generally higher than in the cerebrum and, particularly, MK‐801, the most potent drug in the cerebrum, was without significant effect in the cerebellum, at any time and at doses as high as 30 mg/kg. N‐[1‐(2‐benzo(b) thiophenyl) cyclohexyl]piperidine (BTCP), desipramine, and atropine showed a more efficient prevention of 3H‐TCP binding in the cerebellum than in the cerebrum. The prevention of the binding by TCP or PCP, at doses close to their ID50 values, was rapid and then decreased slowly. The effect of MK‐801 was long‐lasting. This study confirm previous in vitro studies: 3H‐TCP is an efficient tool for the labeling of the NMDA receptor‐associated ionic channel. particularly, low affinity sites were identified in the cerebellum with the same pharmacological properties as in vitro in the same region.