bluuebunny/crossref_metadata_2025_split huggingface dataset:
GM1 ganglioside counteracts selective neurotoxin‐induced lesion of developing serotonin neurons in rat spinal cord
Authors: Fusco M. , Donà M. , Tessari F. , Hallman H. , Jonsson G. , Gorio A. 
Published: January 2005

AbstractThe effect of exogenous monosialo ganglioside GM1 on neurotoxin‐induced lesioning of bulbo‐spinal serotonergic neurons of newborn rats was studied by means of biochemical and immunocytochemical techniques. 5,7‐dihydroxytrypatamine (5,7‐HT, a selective serotonin neurotoxin) treatment of newborn rats caused a pronounced reduction of 5‐hydroxytryptamine (5‐HT) and 5‐hydroxyindoleacetic acid (5‐HIAA) levels in the thoracic and lumbar spinal cord, while an increase of 5‐HT and 5‐HIAA was found in the pons medulla. These biochemical alterations were regionally correlated with similar changes in 5‐HT nerve terminal density analyzed by image analysis. GM1 administration (30 mg/kg for 4 consecutive days) antagonized the reduction of 5‐HT and 5‐HIAA levels induced by 5, 7‐HT treatment in the lumbar spinal cord of 2‐month‐old rats, as well as the decrease of 5‐HT nerve terminal density in both thoracic and lumbar spinal cord of 1‐ and 2‐month‐old rats. A minor counteracting effect of GM1 was found in the pons medulla where the neurotoxin induced an increase of 5‐HT and 5‐HIAA levels. These data support the hypothesis that GM1 may have a preventing action on retrograde degenerative processes following chemical lesion and/or a growth‐stimulating effect on injured 5‐HT neurons.
Theiler's virus in brain cell cultures: Lysis of neurons and oligodendrocytes and persistence in astrocytes and macrophages
Authors: Graves M. C. , Bologa L. , Siegel L. , Londe H. 
Published: January 2005

AbstractThe mechanisms of presistence and of demyelination in Theiler's virus (TV)‐induced chronic neurologic disease (a murine model for multiple scelerosis) are, as yet, disputed. We investigated the tropism and persistence of TV in brain cell culture to better understand the pathogenesis of this disease. Using anti‐genic markers to identify specific cells in culture, we have demonstrated that TV infects, lytically, neurons and oligodendrocytes and persistently astrocytes and macrophages. These results suggest that host cell factors play a key role in the mechanism of demyelination and the persistence of TV in the nervous system.
Regulation of myelin basic protein in oligodendrocytes by a soluble neuronal factor
Authors: Bologa L. , Aizenman Y. , Chiappelli F. , de Vellis J. 
Published: January 2005

AbstractMyelin basic protein (MBP) is one of the most important myelin components. Based on our previous studies, we hypothesized that neurons might have regulatory effects on the production of MBP by oligodendrocytes, and we conducted studies designed to verify this hypothesis. Oligodendroglia‐rich cultures from total brain of neonatal rats or mice and pure cultures of embryonic rats or chicks were prepared. Cultures of mouse fibroblasts and astrocytes were prepared as well. We show here that MBP production by oligodendrocytes was greatly enhanced by treatment with either pure neurons, rat neuronal conditioned medium, or chick neuronal conditioned medium, while chemically defined, hormonally supplemented medium or medium conditioned by astroctyes and fibroblasts had no effect on MBP expression. We conclude that the production of MBP by oligodendrocytes is regulated by a nonspecies specific soluble neuronal factor. The conservation of this phenomenon from avian to rodent species implies its critical role in myelination and suggests its potential application as a treatment in demyelination.
Rapid, high‐resolution in situ hybridization histochemistry with radioiodinated synthetic oligonucleotides
Authors: Lewis M.E. , Arentzen R. , Baldino F. 
Published: January 2005

AbstractIn situ hybridization histochemistry is a valuable technique for localizing specific messenger RNA (mRNA) and detecting changes in gene expression. Generally, the mRNA of interest has been detected by probes obtained from cloned DNA and labelled to high specific activity by nick translation. Such probes have a number of disadvantages which can be circumvented by the use of short synthetic oligonucleotides designed to be complementary to a known mRNA sequence. We report here that synthetic oligonucleotides complementary to part of the mRNA coding for rat arginine vasopressin (AVP) can be labelled to high specific activity with [125I], using either the primer extension method with the Klenow fragment of DNA polymerase I or the 3′‐tailing method with terminal deoxynucleotidyl transferase. Both AVP probes hybridized well to the magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei. A strong autoradiographic signal was present by 2 days, with grains largely confined to the perikaryon. These results compare favorably to those obtained with [32P]‐ or [3H]‐labelled probes. Given the ease of the 3′‐tailing method, [125I]‐labelled oligonucleotides appear to be especially useful probes for in situ hybridization histochemistry.
In situ hybridization histochemistry for the analysis of gene expression in the endocrine and central nervous system tissues: A 3‐year experience
Authors: Bloch B. , Popovici T. , Le Guellec D. , Normand E. , Chouham S. , Guitteny A.F. , Bohlen P. 
Published: January 2005

AbstractWe report our experience in development of the in situ hybridization (ISH) procedure to detect messenger RNAs (mRNAs) coding for various molecules involved in endocrine glands and central nervous system activity, including mRNAs coding for endorphin precursors [preproenkephalin A (PPA), pro‐opiocortin (POMC)], vasopressin, and transferrin. Various conditions of fixation and handling of the tissues were tested to establish optimal parameters for mRNA detection. Double‐stranded DNA probes labeled by nick translation, synthetic oligonucleotides labeled at their 5′ end, as well as single‐stranded RNA probes were used, after incorporation of 32P‐ or 35S‐labeled nucleotides. Specific requirements for efficient and reproducible ISH investigations are discussed. Cells expressing the PPA gene in the adrenal medulla and in the brain were detected by ISH. The results show that ISH is as sensitive as immunohistochemistry in detecting peptide‐producing cells in the adrenal and that it allows detection of PPA cell bodies in brain in conditions in which they are inconstantly detected by immunohistochemistry. Unilateral destruction of substantia nigra provokes a dramatic decrease in the number of neurons expressing the PPA gene in the controlateral striatum. Cells expressing the POMC gene were detected in the pituitary of various species including man and in the rat arcuate nucleus. Neurons containing vasopressin mRNA were visualized in the supraoptic paraventricular and suprachiasmatic nucleus of the adult rat by using a synthetic oligonucleotide probe. Transferrin gene expression was shown in the central nervous system of the rat brain in two cell populations, the oligodendrocytes and the epithelial cells of the choroid plexus, by demonstration of simultaneous presence in them of transferrin immunoreactivity together with transferrin mRNA. These results show that the ISH procedure is a technique that can be routinely used to investigate gene transcription anatomically in complex heterocellular tissues such as the endocrine glands and the nervous system.
Chromaffin cell heterogeneity of process formation and neuropeptide content under control and nerve growth factor‐altered conditions in cultures of chick embryonic adrenal gland
Authors: Shaw T.J. , Letourneau P.C. 
Published: January 2005

AbstractAdrenal glands from embryonic day 11 (E‐11) chicks were cryostat‐sectiond, and it was determined that tyrosine hydroxylase‐like immunoreactive (TLI) cells, somatostain‐like immunoreactive (SLI) cells, and methionnie‐enkephalin‐like immunoreactive (ELI) cells occupied chromaffin regions of the gland. Similar age adrenals were dissociated, and the cells were cultured under serum‐free conditons. Cultured TLI cells, ELI cells, and SLI cells were characterized according to cell size, cell number, and neurite formation. ELI and SLI cells composed two largely separate populations, with SLI cells tending to have larger cell areas, to be more numerous, and to be less likely to from neurits than ELI cells. The population of TLI cells, although unique in itself, was diverse and numerous enough to include all or portions of the neuropeptide‐immunoreactive populations. Neurites of some cells from each of the above populations were strongly immunoreactive for alpha neurofilament protein, and for NAPA73 neurofilament‐associated protein. However, neurities could also be observed in all populations that showed poor immunoreactivity for these cytoskeletal proteins. Exogenously added NGF significantly increased nurite‐like process formation among TLI and ELI cells, but not among SLI cells. Reductions in the number of neurite‐like processes following treatment with anti‐nerve growth factor (NGF) were not singnificant for any of the populations. However, if shorter and broader process were included, ELI cells. Anti‐NGF inhibition of process formation among ELI cells could be reversed with exogenous NGF. Neither NGF or anti‐NGF treatments showed a significant effect on cell numbers among TLI and ELI populations. The implications are that a compound of antigenic and physiologic similarity to mouse salivary NGF is made by embryonic chick adrenal cells in culture, but the effects of NGF do not appear to be the same for all neural‐crest‐derived cells from the adrenal, and greater heterogeneity of phenotypes may exist among chromaffin cells than has previously been accepted. Some quesitons are also raised concerning the neurite‐like nature of processes formed by some chromaffin cells in vitro.
β‐Adrenergic stimulation of protein (arginine) methyltransferase acitivity in cultured cererbral cells from embryonic mice
Authors: Amur S.G. , Shanker G. , Pieringer R.A. 
Published: January 2005

AbstractSeveral adrenergic effectors and neurotransmitters were tested as potential regulators of myelin basic protein (MBP) and histone methyltransferase activities. Both enzymes were specifically activated by β‐adrenergic agonists in a stereospecific manner. Cyclic AMP (but not AMP) stimulated the enzymes to the same extent as did the β‐adrenergic agonist, (−) isoproterenol. The studies suggest that β‐adrenergic agonists stimulate adenylate cyclase thereby causing an increased production of cyclic AMP which stimulates the methyltransferases. Cycloheximide addition to the reaction mixture did not affect the stimulation due to cyclic AMP, indicating that new protein synthesis is not involved in the cyclic AMP stimulation of the methyltransferases. Thyroid hormone (T3) has been shown to stimulate MBP methyltransferase [Amur et al, 1984] and could exert its stimulatory effect through β‐adrenergic‐dependent systems. Thus, the methylation of MBP seems to be regulated both by T3 and by neurotransmitters and/or hormones mediating their effects through cyclic AMP production, whereas the methylation of histones seems to be regulated only by the latter.
Decreased acetylcholine receptor content in denervated skeletal muscles infused with nerve extract
Authors: Sayers S.T. , Yeoh H.C. , McLane J.A. , Held I.R. 
Published: January 2005

AbstractThe influence of a concentrated extract of soluble substances from the sciatic nerve upon the acetylcholine receptor (AChR) content in the soleus muscle of adult rats was examined by in vivo infusions. Internal and membrane‐inserted AChR were quantitated by the specific binding of 125I‐alpha‐bungarotoxin (a‐BuTX). Interestingly, the nerve extract had no apparent effect unless the soleus muscle was also denervated at the start of the infusion. Then, after 66 hr, substantially less (60‐80%) binding of125I‐a‐BuTX to AChR was observed compared to denervated solei that did not receive an infusion of nerve extract. However, the concentration of protein in the nerve extract had to exceed 5 mg/ml before this effect was evident. Infusions of phosphate‐buffered saline, bovine serum albumin, rat liver extract, or human transferrin had no striking effect upon AChR. The prevention of the characteristic denervation‐induced increase in nonjunctional AChR by an active component in the nerve extract may be due to a trophic signal for decreased synthesis of AChR, but it is also possible that the degradation of AChR was increased.
The β subunit of the guanine nucleotide regulatory proteins: Identification of its location on two‐dimesional gels of brain tissue and its regional and subcellular distribution in brain
Authors: Heydorn W.E. , Gierschik P. , Creed G.J. , Milligan G. , Spiegel A. , Jacobowitz D.M. 
Published: January 2005

AbstractThe β subunit of the guanine nucleotide regulatory proteins (also termed G proteins) has been examined in both rat and human brain, a single protein of molecular weight 36,000 daltons and pI 5.8 reacted the antisera. This protein also comigrated with one of the proteins present in a purified preparation of bovine brain G proteins. Based upon molecular weight, pI, and reactiion with specific antisera, it was concluded that this protein is the β subunit of the G proteins in brain. Using this information, the regional and subcellular distribution of the G protein β subunit was studied in rat brain. Of 25 distinct neuroanatomical areas examined, cortical regions were generally found to contain the largest amount of this protein. The subcellular distribution of the G protein β subunit revealed that large amounts are present in the synaptic membrane, crude synaptic vesicles, and microsomes. These studies serve to identify another protein visible on silver‐stained two‐dimensional electrophortograms of rat and human brain. The regional and subcellular distribution of the G protein β subunit correlate well with the proposed physiological function of this protein.
Characterization of epitopes shared by α‐melanocyte‐stimulating hormone (α‐MSH) and the 150‐kd neurofilament protein (NF150): Relationship to neurotrophic sequences
Authors: Verhaagen J. , Edwards P.M. , Schotman P. , Jennekens F.G.I. , Gispen W.H. 
Published: January 2005

AbstractImmunoblot techniques and immunohistochemistry have been used to investigate epitopes shared by α‐melanocyte‐stimulating hormone (α‐MSH) and the 150‐kD neurofilament protein (NF150). Three anti‐α‐MSH antisera (namely 31H2T, 4394, and M5) from a total of 12 sera were found to react with NF150. The three crossreacting sera are different in their binding properties to peptide fragments related to α‐MSH, suggesting that at least two distinct epitopes are shared by NF150 and α‐MSH. The only known sequence common to NF150 and α‐MSH, the N‐terminal Ac‐S‐Y residues, appears to be essential for binding of sera 31H2T and 4394. However, the binding of antiserum M5 involves other, currently unknown, similarities between NF150 and α‐MSH. This is shown by the binding of M5 to peptides such as ACTH(4–10), which do not contain the N‐terminal Ac‐S‐Y sequence. Binding of M5 to tobacco mosaic virus coat protein (TMV‐coat protein), which is homologous with α‐MSH and NF150 in its Ac‐S‐Y residues, was negligible. The peptide structures that are recognized by M5 have previously been shown to exert neurotrophic activity. The data are discussed in the light of the hypothesis that similarity between NF150 and α‐MSH, as illustrated by binding to M5, may be significant in the neurotrophic activity of MSH‐related peptides.
Comparative screening for ciliary neurotrophic activity in organs of the rat and chicken
Authors: Ebendal T. 
Published: January 2005

AbstractA neuron‐survival assay with dissociated ciliary ganglion neurons was used to examine the level of neurotrophic activity in organs of the rat and chicken. All tissue homogenates enhanced neuron survival at increasing protein concentrations, although 50% survival activity (1 trophic unit, TU, per ml) occurred at distinctly different levels in the different organs. Liver, spleen, T‐cells, and submandibular gland from the rat were very low in survival‐promoting activity (0.1–1.1 TU per mg of protein). Serum and lung were slightly richer (2.4–2.8 mg). Heart, brain, and skeletal muscle stimulated survival well (6.2–13 TU/mg). Unexpectedly, the highest activities were found in the rat kidney (44 TU/mg). The activity in adult chicken organs was less varied (1.6–9.1 TU/mg). Higher trophic activities were found in the chicken embryo, particularly at day 18 of development (20–30 TU/mg). The up to 100‐fold difference in trophic level between organs should make it feasible to use subtractive hybridization, differential screening, and transient expression in eukaryotic cells for molecular cloning of the ciliary neurotrophic factor(s).
Basal forebrain magnocellular neurons stain for nerve growth factor receptor: Correlation with cholinergic cell bodies and effects of axotomy
Authors: Springer J. E. , Koh S. , Tayrien M. W. , Loy R. 
Published: January 2005

AbstractRecent evidence has demonstrated the presence of nerve growth factor (NGF) in areas of the central nervous system characterized by cholinergic innervation. We report that a unique population of rat basal forebrain magnocellular neurons that project to the cortex and hippocampus are immunoreactive to a monoclonal antibody to the NGF receptor. Removal of target contact results in a time‐dependent loss or shrinkage of cells in the basal forebrain that stain for NGF receptor and acetylcholinesterase, suggesting that under normal conditions, basal forebrain cholinergic neurons utilize NGF for trophic support.
Characteristics of synaptic currents in frog muscle fibers of different types
Authors: Uchitel O. D. , Miledi R. 
Published: January 2005

AbstractA study was made of synaptic currents in voltageclamped muscle fibers of the frog. Fast, submaxillaris, and slow muscle fibers are innervated by nerve fibers of different conduction velocities. To avoid spatial complications, transmitter release by nerve impulses was restricted to the site of recording and reduced to single quanta (unitary endplate currents: uepc). Following nerve stimulation, the time course of transmitter release was longer and more variable in slow and submaxillaris muscle fibers than in the fast fibers. The time constant of decay of uepc in submaxillaris and slow fibers was, respectively, about 1.8 and 2.9 times slower than the decay of uepc in fast fibers. This is due mainly to differences in the lifetime of the channels opened by acetylcholine. The neuromuscular junctions in submaxillaris muscle fibers are boutonlike or longer branched contacts; and the unitary currents in the bouton junctions have a slower time course. It is concluded that the synaptic membrane in the different types of muscle fibers has synaptic acetylcholine‐operated channels that have different kinetic properties, and that these properties are determined by the type of axon that innervates the muscle fiber.
Comparison between acute and chronic effects of ammonia on branched‐chain amino acid oxidation and incorporation into protein in primary cultures of astrocytes and of neurons
Authors: Murthy C. R. K. , Hertz L. 
Published: January 2005

AbstractA comparison was made of acute and chronic effects of ammonia on production of 14CO2 from the [U‐14C] labeled branched‐chain amino acids (BCAA) leucine, isoleucine, and valine as well as from [1‐14C] leucine, and on the incorporation of radioactivity from these amino acids into a perchloric‐acid‐precipitable protein fraction in astrocytes and neurons in primary cultures.Acute exposure of astrocytes to 3mM ammonium chloride suppressed 14CO2 production from [U‐14C] BCAA and especially from [1‐14C] leucine. This inhibitory effect was abolished or even reversed ([U‐14C] leucine) after chronic exposure to ammonia. Analogously, incorporation of radioactivity into the protein fraction was inhibited after acute exposure but not after chronic exposure of astrocytes to ammonia. The total protein content per culture was increased after chronic exposure. In neurons, production of 14CO2 and incorporation of 14C into proteins were less affected than in astrocytes. These results are discussed in relation to the ability of the two cell types to synthesize glutamine.
Cyclic nucleotide phosphodiesterase isozymes in neuroblastoma cells
Authors: Walz M. A. , Holt I. L. , Howlett A. C. 
Published: January 2005

AbstractAdenosine 3′,5′‐cyclic monophosphate (cAMP) content of neurons is determined not only by the rate of synthesis but also by the rate of hydrolysis by cyclic nucleotide phosphodiesterases. Multiple forms of cyclic nucleotide phosphodiesterase exist in brain and other tissues, and these may be regulated by various hormones and neuromodulators. The present study examines this regulation in a cloned line of neuroblastoma cells (N18TG2). A biphasic Lineweaver‐Burk plot of cAMP hydrolysis revealed two Kms approximating 5 and 25 μM. Lineweaver‐Burk plots of cGMP hydrolysis were linear over a range of 1 μM to 1 mM and exhibited a Km of 37 μM. Neither cAMP nor cGMP competed for hydrolysis of the alternative cyclic nucleotide. No evidence for an allosteric activation of cAMP phosphodiesterase by cGMP was found. Calcium regulation of phosphodiesterase was not found in spite of preparation of the cell extract with several protease inhibitors, and addition of exogenous calmodulin. No effect of calmodulin antagonists (calmidazolium, W7, or trifluoperazine) was observed in vitro or in situ. Growth of the cells in the presence of 200 nM 3,5,3′‐triiodothyronine (T3) resulted in an increased hydrolysis of cAMP but not of cGMP. This increase was attributed to an increase in Vmax with no change in either high or low Km. This response was blocked by cycloheximide, suggesting that the thyroid hormone effect requires protein synthesis. The thyroid hormone response in neuroblastoma cells is compared with the results of other studies of thyroid hormone effects on phosphodiesterase in other tissues in vivo.
Differential effect of mu, delta, and kappa opioid agonists on adenylate cyclase activity
Authors: de Montis G. M. , Devoto P. , Preti A. , Tagliamonte A. 
Published: January 2005

AbstractD‐Ala2, D‐Leu5‐enkephalin (DADLE) and dynorphinl–13 (Dynl–13) inhibited striatal adenylate cyclase activity, both basal and dopamine‐stimulated (DA), in rats and guinea pigs. The κ‐agonists bremazocine (BRZ), U‐50,488 (trans‐3,4‐dicloro‐N‐methyl‐N‐[2‐(1‐pyrrolidiny1)‐cyclohexyl]‐benzeneacetamide), and U‐69,593 (5α, 7α 8β)‐(‐)‐N‐methyl‐N‐(7‐(l‐pyrrolidiny1)‐1‐oxaspiro (4.5) dec‐8yl) benzeneacetamide inhibited only the basal adenylate cyclase activity, and such an effect was restricted to guinea pig striatum, an area known to contain a high density of K‐binding sites. Moreover, BRZ was found to antagonize the inhibitory effect of both DADLE and Dynl–13 in rat striatum.
Cobra nerve growth factor: Structure and evolutionary comparison
Authors: Selby M. J. , Edwards R. H. , Rutter W. J. 
Published: January 2005

AbstractWe have cloned and sequenced an NGF cDNA from the cobra venom gland. The structure of the predicted cobra precursor resembles that of the mouse prohormone, with a highly conserved mature NGF protein at the C‐terminus. In the non‐NGF moiety, a putative signal peptide and two sets of basic residues presumably reflecting cleavage sites that are more conserved, while large interstitial regions are poorly conserved. This moiety may be involved in defining the folding of the precursor for subsequent proteolytic maturation and/or encode a bioactive polypeptide(s). Primer extension analysis indicates a single NGF transcript in the cobra venom gland.