bluuebunny/crossref_metadata_2025_split huggingface dataset:
T lymphocytes can recognize determinants unique to neuropeptides of guinea pig myelin basic protein containing a single D‐isomer amino acid substitution
Authors: Levy R. B. , Miller S. , Garcia N. M. , Jones M. , Fisher G. H. , Man E. H. 
Published: January 2005

AbstractThe present studies were undertaken to examine how the substitution of racemized forms of selected amino acids in synthetic peptides of guinea pig myelin basic protein (GPMBP) would after the host's immunological ability to recognize such molecules. Using peptides from the 69–84 sequence of GPMBP containing a D‐serine at position 70 or 75 (69–84[D‐ser70 or D‐ser75]) or D‐asparate at position 82 (69–84[D‐asp82]), the findings demonstrated that the position of the diastereomer substitution on tthese neuropeptides was critical with respect to the ability of the immune system to recognize the molecule. Thus substitution of D‐asp at position 82 or D‐ser at position 75 abrogated the ability of these peptides to induce experimental autoimmune encephalitis and proliferation of host T cells. In contrast, a peptide containing a D‐ser70 residue was capable of inducing clinical disease in rats, as well as stimulating T lymphocytes from 69–84‐(D‐ser70)‐injected animals. Moreover, although this D‐peptide was shown to share at least determinant(s)‐stimulated cell lines demonstrated that some epitope(s) unique to this molecule could stimulate CD4+ syngeneic T cells.
Effects of MK‐801 on glutamate‐induced swelling of astrocytes in primary cell culture
Authors: Chan P. H. , Chu L. , Chen S. 
Published: January 2005

AbstractThe effects of glutamate and its agonists and antagonists on the swelling of primary astrocytes were studied. Glutamate (Glu), aspartate (Asp), homocysteate (HCA), and quisqualate (Quis) at 1 mM concentration caused a significant increase in astrocytic swelling as measured by the 3‐0‐methyl‐[14C]‐glucose, whereas kainate (KA), N‐methyl‐D‐aspartate (NMDA), and receptor antagonists 2‐amino‐5‐phosphonovaleric acid (APV), 2‐amino‐7‐phosphonohepatanoic acid (APH), and kynurenic acid (Kynu) were not effective. This glial swelling was time‐dependent since 1‐hr or greater incubations with Glu or its agonists were needed to produce such an effect. Preincubation of glutamate or NMDA receptor anatogonists including Kynu, APH, and APV failed to ameliorate the Glu effects. However, MK‐801, a noncompetitive NMDA antagonist, when added to the Glu‐incubated astrocytes significantly reduced Glu‐induced astrocytic swelling. MK‐801 was also effective in reducing the astrocytic swelling induced by agonists including Asp, Quis, and HCA, suggesting that those agonists may share similar mechanisms of Glu in inducing astrocytic swelling. Since the cultured astrocytes lack the NMDA receptors, our data suggest that the observed beneficial effects of MK‐801 on excitotoxin‐induced swelling of astrocytes may be mediated by mechanisms other than NMDA receptors.
Modification of serotonergic innervation of the rat spinal cord dorsal horn after neonatal capsaicin treatment
Authors: Marlier L. , Rajaofetra N. , Poulat P. , Privat A. 
Published: January 2005

AbstractNewborn rats were treated with Capsaicin. Seven weeks later, calcitonin gene‐related peptide, substance P, and serotonin were detected immunocytochemically in the dorsal horn of the spinal cord. Peptide immunostaining, presumably located in primary afferents, was reduced in intensity, whereas the pattern of serotonin innervation was modified, suggesting a secondary reorganization due to the lesion of afferents. The possible mechanisms of this reorganization are discussed.
Coexpression of lactosyl and ganglioteraosyl gangliosides in rat cerebellar radial glial cells in culture
Authors: Gravotta D. , Ferreira A. , Busciglio J. , Caceres A. , Landa C. A. , Maccioni H. J. F. 
Published: January 2005

AbstractThe expression of gangliosides of the lactosylceramide (LC) and of the gangliotertrasylceramide (GTC) series on the surface of cells from rat embryonic cerebellar tissue was investigated by double‐color indirect immunofluorescence. GD3 was assumed to be representative of LC and was detected using a specific monoclonal antibody. GM1 was assumed to be representative of GTC and was detected using the binding of cholera toxin followed by the binding of cholera toxin antibodies. The expression of polysialosylated GTC (polysialosy‐GTC) was detected using the cholera toxin‐cholera toxin antibody experimental approach after conversion of polysialosyl‐GTC to GM1 by treatment of the cells with neuraminidase.To distinguish the major neural cell types present in the cultures the expression of the following cell type‐specific markers was investigated: neurons‐specific markers was investigated: neuron‐specific enolase and microtubule‐associated protein‐2 (MAP‐2) as probes for neuronal cells and the intermediate filament protein glial fibrillar acidic protein (GFAP) as a probe for astroglial cells.More than 80% of cells dissociated from cerebellar tissue of 15‐day‐old rat embryos (E15) are positive for the expression of GD3 and about 50% for the expression of GM1 and polysialosyl‐GTC, but most are negative for the expression of neuron‐specific enolase, MAP‐2, and GFAP. After culturing for 4 days (E15+4) most cells that show characteristics of neuronal cells are positive for the expression of polysialosyl‐GTC and “inactivate” the expression of GD3. Most cells with characteristics of radial and stellate glial cells are also positive for the expression of polysialosyl‐GTC, but unlike neuron‐like cells, they do not “inactivate” the expression of GD3.
Mechanical changes associated with synaptic transmission in the mammalian superior cervical ganglion
Authors: Kusano K. , Tasaki I. 
Published: January 2005

AbstractMechanical changes in the superior cervical ganglion (SCG) of the guinea pig, evoked by stimulating the pre‐or postganglionic nerve, were determined by using a mechano‐electric transducer. The mechanical change evoked by either one of these nerves was monophasic, an initial phase of rapid swelling (about 1 dyn/cm2) being followed by a slow relaxation. The mechanism of these mechanical changes was examined by treating the preparations with agents which are known to suppress or facilitate synaptic transmission in the SCG. Mechanical changes elicited by preganglionic nerve stimulation were suppressed by agents that reversibly block ganglionic transmission (Ca2+ ‐free high Mg2+, d‐tubocurarine, hexamethonium, TEA, TTX). On the other hand, agents which are known to facilitate synaptic transmission (high Ca2+) increased both the amplitude and the duration of swelling. In a Ba2+‐containing medium, a large, long‐lasting shrinkage of the ganglion was observed. It is suggested that the mechanical changes recorded in this study are associated with postsynaptic electrogenesis.
Heat generation associated with synaptic transmission in the mammalian superior cervical ganglion
Authors: Kusano K. , Tasaki I. 
Published: January 2005

AbstractBy use of a thermal detector constructed with a thin polyvinylidene fluoride film (PVDF), heat production in the superior cervical ganglion (SCG) of the guinea pig was examined. A single electric shock applied to the preganglionic nerve evokes a temperature rise of approximately 1.5 × 10−6 deg. The thermal responses summate when the preganglionic nerve is stimulated repetitively. The amplitude of the thermal response is increased when the preparation is treated with a high Ca2+ medium. Treatment with agents that block ganglionic transmission (high Mg2+, d‐tubocurarine, hexamethonium, TTX) reversibly suppresses thermal response. It is thus concluded that the thermal responses described in this paper are generated by the physio‐chemical events underlying postsynaptic electrogenesis in the SCG cells.
Spiny neurons lacking choline acetyltransferase immunoreactivity are major targets of cholinergic and catecholaminergic terminals in rat striatum
Authors: Pickel V. M. , Chan J. 
Published: January 2005

AbstractThe ultrastructural substrate for functional interactions between intrinsic cholinergic neurons and catecholaminergic afferents to the caudate‐putamen nucleus and nucleus accumbens septi (NAS) was investigated immunocytochemically. Single sections of glutaraldehyde‐fixed rat brain were processed (1) for the immunoperoxidase labeling of a rat monoclonal antibody against the acetylcholine‐synthesizing enzyme choline acetyltransferase (CAT) and (2) for the immunoautoradiographic localization localization of a rabbit polyclonal antiserum against the catecholamine‐synthesizing enzyme tyrosine hydroxylase (TH). The ultrastructural morphology and cellular associations did not significantly differ in the caudate‐putamen versus NAS. Immunoperoxidase reaction for CAT was seen in perikarya, dendrites, and terminals, whereas immunoautoradiography for TH was in terminals. The perikarya and dendrites immunolabeled for CAT were large, sparsely spiny, and postsynaptic mainly to unlabeled axon terminals. Only 2–3% of the CAT‐labeled terminals (n = 136) and less than 1% of the TH‐labeled terminals (n = 86) were apposed to, or formed synapses with, perikarya or dendrites immunoreactive for CAT. Most unlabeled and all labeled terminals formed symmetric synapses. In the same sample, 18% of the CAT and 16% of the TH‐labeled terminals were directly apposed to each other. Unlabeled dendritic shafts received the major (40% for CAT versus 23% for TH) synaptic input from cholinergic terminals, while unlabeled spines received the major (47% for TH versus 23% for CAT) synaptic input from catecholaminergic terminals. Neither the unlabeled dendrites or spines received detectable convergent input from CAT and TH‐labeled terminals. Thirteen percent of the CAT‐labeled and 14% of TH‐labeled terminals were in apposition to unlabeled terminals forming asymmetric, presumably excitatory, synapses with unlabeled dendritic spines. We conclude that in both the caudateputamen and NAS cholinergic and catecholaminergic terminals (1) form symmetric, most likely inhibitory, synapses primarily with non‐cholinergic neurons, (2) differentially synapse on shafts or spines of separate dendrites, and (3) have axonal appositions suggesting the possibility of presynaptic physiological interactions. These results support the hypothesis that the cholinergic‐dopaminergic balance in striatal function may be mediated through inhibition of separate sets of spiny projection neurons with opposing excitatory and inhibitory functions.
Low‐abundance 32‐kilodalton nuclear protein specifically enriched in the central nervous system
Authors: Shelton K. R. , Cunningham J. G. , Klann E. , Merchant R. E. , Egle P. M. , Bigbee J. W. 
Published: January 2005

AbstractRecently, a low‐abundance nuclear protein, p32/6.3, has been identified in brain tissue (Egle and Shelton: Journal of Biological Chemistry 261:2294–2298,1986). Using a Western blot procedure, we describe its distribution in the nervous system, determine its relative enrichment in brain versus liver, kidney, and certain other tissues, and describe an isolation procedure from brain. Selective enrichment occurs in basal ganglia, diencephalon, hippocampus, cerebellum, brainstem, spinal cord, and cerebral cortex but not in retina, dorsal root ganglia, and sympathetic ganglia. Thus, enrichment is limited to areas of the central nervous system. p32/6.3 appears to be preferentially enriched in neurons, because in bulk‐isolated fractions from rat grey matter it is more abundant in neuron‐enriched fractions than in astrocyte‐enriched fractions. p32/6.3 is approximately 20‐fold more concentrated in an insoluble nuclear protein or matrix fraction from forebrain than from kidney, liver, adrenal gland, or retina. This degree of enrichment is an ancient trait, detectable in the chicken as well as mammals.
Cholinergic function in cultures of mouse spinal cord neurons
Authors: Wang F. Z. , Nelson P. G. , Fitzgerald S. C. , Hersh L. B. , Neale E. A. 
Published: January 2005

AbstractCholinergic synapeses formed in cultures of fetal mouse spinal cord (SC) and superior cervical ganglion (SCG) were studied using intracellular and extracellular stimulation and recording as well as immunohistochemical staining for choline acetylransferase (ChAT).Dissociated SC neurons and SC explants exhibited cholinergic terminals on SCG and SC neurons as demonstrated by ChAT immunoreactivity. Intracellular recording s showed that cholinergic inputs to SCG neurons were relatively common and that these synaptic inputs were blocked by the nicotinic acetylcholine (ACh) receptor blocker, tubocurarine. A comparison of three preparatios indicated that the incidence of cholinergic activity recorded in SCG neurons was significantly higher in co‐cultures of SCG with spinal cord ventral horn (VH) neurons grown on a substrate of non‐neuronal cells from cerebral cortex, than in co‐cultures with VH alone or with SC and dorsla root ganglion cells. Consistency between cholinergic physiology and staining for ChAT‐positive terminals on SCG neuronal somata was obtained in cultures of SC explants grown with dissociated SCG.Application of acetylcholine, muscarine, and /or vasoactive intestinal polypeptide (VIP) produced slow excitation of SC neurons. Fast excitatory cholinergic interactions between SC neurons were not observed. Excitatory synaptic interactions between SC neurons were augmented by ACh or muscarine, while inhibitory synaptic interactions were diminished. Both types of synaptic modulation probably were produced by a presynaptic mechanism. Acetylcholine or muscarine affected synbaptic interactions between SC neurons in only one‐third of the synaptic connections tested, suggesting that the incidence of presynaptically cholinoceptive SC neurons is low in dissociated cell cultures.The experimental results show that a culture system incorporating dissociated fetal mouse SC neurons or explants of SC with sympathetic ganglion neurons expresses both nicotinic and muscarinic cholinergic function.
Different pathogenicity of encephalitic togaviruses in organotypic cultures of spinal cord slices
Authors: Shahar A. , Lustig S. , Akov Y. , David Y. , Schneider P. , Levin R. 
Published: January 2005

AbstractThe pathogenicity of two encephalitic Togaviruses, Sindbis virus (SV), an alphavirus, and West Nile virus (WNV), a flavivirus, was studied in organotypic cultures of fetal mouse spinal cord slices grown in roller tubes. After about 3 weeks in vitro, during which time the cultures became abundantly myelinated, they were infected either by 5 × 105 PFU SV or by 5 × 106 PFU WNV per culture. The viruses caused different patterns of cytopathogenicity: SV induced severe cytotoxicity in all glia cells and neurons with concomitant demyelination within 48 hr. In contrast, WNV, even 4 days after infection, caused only mild cytopathic effects mainly to neurons and astrocytes and a slight degree of damage to the myelin sheath. A most remarkable finding was the entrapment of WNV particles in the interperiod lines of the myelin sheaths. Treatment of cultures with mouse alpha and beta interferon prior to their infection with either virus protected the cultures from any viral damage. Long‐term exposure of non‐infected control organotypic cultures of fetal spinal cord slices to mouse interferons had no significant effect on neuronal and glial differentiation, and myelin formation.
Alzheimer disease proteins (A68) share epitopes with tau but show distinct biochemical properties
Authors: Ksiezak‐Reding H. , Binder L. I. , Yen Shu‐Hui 
Published: January 2005

AbstractAlz 50, a monoclonal antibody raised against Alzheimer brain homogenate, reacts with neurofibrillary tangles, microtubule‐associated proteins tau, and Alzheimer brain proteins of molecular weight 70–60 kDa (A68). To study the relationship between A68 and normal human tau we compared the biochemical properties of these proteins and tested the reactivity of A68 with eight antibodies (Alz 50, Tau 60, Tau‐2, Tau 14, Tau‐1, Ab 636.7, NP14, Tau 46) that bind to various regions of tau molecule. On Western blots, all tau‐reactive antibodies, except Tau‐1, recognized A68. Pretreatment with alkaline phosphatase was required for the Tau‐1 binding to A68. A68 consisted of three polypeptides of 68, 64, and 60 kDa, while tau contained 4–6 polypeptides of 50–65 kDa. A68 was less heterogenous than tau in the number of pl variants on two‐dimensional gels. All A68 variants were more acidic (pl 5.5–6.5) than human tau (pl 6.5–8.5). Phosphatase treatment had only a minor effect on the pI and mobility of A68. Limited proteolysis of A68 with trypsin or chymotrypsin generated large fragments of 56–66 kDa (chymotrypsin) and 40–45 kDa (trypsin). While none of the fragments was recognized by Alz 50, the chymotryptic fragments were reactive with all the other tau antibodies, and the tryptic fragments were positive with five of the antibodies (Tau 14, Tau‐1, Ab 636.7, NP14, and Tau 46). The peptide maps of A68 differed from that of tau in the number and the size of the peptide fragments. The differences in biochemical properties of these proteins and the sharing multiple epitopes suggest that A68 is a modified form of tau. The modification in part may be due to phosphorylation, although other changes rendering different isoelectrical properties and susceptibility to proteases need to be considered. The removal of the Alz 50 epitope by a cleavage of a 2–3 kDa fragment which does not contain the most C‐terminal epitope (Tau 46) indicates that the Alz 50 epitope is located at the N‐terminal periphery of the A68 molecule.
Enzymatic activites during differentiation of the human neuroblastoma cells, LA‐N‐1 and LA‐N‐2
Authors: Singh I. N. , Sorrentino G. , McCartney D. G. , Massarelli R. , Kanfer J. N. 
Published: January 2005

AbstractThe presence of 10−5 M retinoec acid (RA) in the culture medium of LA‐N‐1, a catecholamonergic cell line, and LA‐N‐2, a cholinergic cell line, enhanced their morphological differentiation. Tyrosine hydroxylase (TH) activity of the LA‐N‐1 cell was increased in the RA‐treated cells compared with control cultures at day 4 and remained elevated. Choline actyltransferase (ChAT) activity in the LA‐N‐2 cells gradually increased until 8 days in vitro (DIV) voth in the untreated control and the RA treated cultures. This activity in control and treated cells decreased gradually to a constant level of activity. The ChAT activity at 8 DIV of RA‐treated La‐N‐2 cells was increased 2.1‐fold (P<0.001) as compared to the control cultures. This increase in ChAT activity was accompanied by a 73% decrease of acetylcholinesterase (AChE) activity in LA‐N‐2 cell by 8DIV. AChE activity of LA‐N‐1 cells was unchanged during the time course of the experiment. Phospholipase‐A2 (PL‐A2)activity in RA‐treated LA‐N‐2cells was increased at day 4 as compared with the control cultures. There were no differnces obseved in phopholipase‐D (PL‐D), choline kinase and FPC‐phosphodiesterases activities in RA‐treated and ‐untreated LA‐N‐1 and LA‐N‐2 cells.
Pineal gland as a model to elucidate the primary mode of action of alpha‐methyldopa: Alpha‐methyldopa induces an increase in the synthesis of N‐acetylserotoni and melatonin levels by the rat pineal gland
Authors: Welman A. D. , Daya S. 
Published: January 2005

AbstractAn attempt was made to use the pineal gland as a model for the study of the primary mode of action of alpha‐methyldopa, which is still unclear. Organ cultures of pineal glands from rats treated chronically with alpha‐methyldopa showed enhanced conversion or radio‐active serotonin to melatonin (aMT) as well as its precursor, N‐acetyl‐serotonin (aHT). This treatment was also found to raise serotonin‐N‐acetyltransferase (NAT) activity. Thse increases associated with alpha‐methyldopa treatment were further enhanced by the beta‐adrenergic agonist, isoproterenol, suggesting a supersensitivity‐type effect occurring at the level of the beta‐receptor. A subsequent binding study, however, showed a decrease in betareceptor binding with exposure to alpha‐methyldopa, providing mitigating eveidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha‐methyldopa acts as an alpha 1 and beta‐agonist, resulting in greater melatonin (aMT) and N‐acetylserotonin (aHT) synthesis than by a beta‐agonist, isoproterenol.
Neural influences on synovial mast cell density in rat
Authors: Levine J. D. , Coderre T. J. , Covinsky K. , Basbaum A. I. 
Published: January 2005

AbstractThe mast cell, an immunocompetent cell that contributes to neurogenic inflammation in a variety of tissues, including synovium, is found in close proximity to peripheral terminals of unmyelinated primary afferents and sympathetic postaganglionic nerve terminals. In this study we evaluated the hypothesis that the density of mast cells in synovial tissue is dependent on the neural innervation. In normal rats, we found that the density of mast cells in the ankle joint capsule, which is heavily innervated, is greater than in the capsule of the knee, which is less densely innervated. Selective lesions of unmyelinated primary afferents with capsaicin, or of sympathetic postganglionic neurons with guanethidine, produced a significant decrease in mast cells; surgical removal of the parasympathetic ganglia did not significantly affect mast cell density. Finally, the number of mast cells in the synovial joint of spontaneously hypertensive rats, which have increased sympathetic activity, was significantly greater than in normotensive control rats. These observations support the hypothesis that the innervation in the synovial joint of the rat, by unmyelinated afferents and sympathetic efferents, exerts a trophic effect on mast cell density.
Morphological changes in cultures of hippocampus following prenatal irradiation in the rat
Authors: Hamdorf G. , Shahar A. , Cervós‐Navarro J. , Schemer A. , Sparenberg A. , Skoberla A. 
Published: January 2005

AbstractThe effect of prenatal irradiation was studied in organotypic cultures of hippocampus, prepared from newborn rats that had been exposed to wholebody irradiation of 1 Gy from a 60Co‐source at day 13 of pregnancy. Light and electron microscopic observaions showed remarkable damage to neuronal mitochondria accompanied by extensive swelling, vacuolation of the Golgi complex, and formation of multilamellar bodies and vesicles of the lysosomal type. In contrast to neuronal alterations, no delay in synaptogenesis or onset of myelination was observed based upon the absence of significant morphological changes in synapses and myelin sheaths. Using this tissue culture model it could be confirmed that prenatal exposure to irradiation, even at low doses, induces specific morphological changes in the brain.
Changes on cerebral antioxidant enzymes, peroxidation, and the glutathione system of frogs after aging and catalase inhibition
Authors: de Quiroga G. Barja , Pérez‐Campo R. , López‐Torres M. 
Published: January 2005

AbstractThe five major antioxidant enzymes, glutathione, and in vivo or in vitro stimulated (Fe++‐ascorbate) peroxidation were similar in old and young Rana perezi frogs. Long‐term (2.5 months) treatment with aminotrizole strongly decreased cerebral catalase (CAT) activity and increased in vivo but not in vitro peroxidation in the brain. This suggests that the increase in endogenous brain peroxidation after CAT inhibition is due to an increased free‐radical attack on cerebral membranes, and not to a possible increase in their sensitivity to peroxidative damage. The increase of in vivo peroxidation is especially remarkable taking into account the low levels of CAT present in the vertebrate brain. On the other hand, these changes were not accompanied by any effect on the survival of the animals. Comparison of these results with those obtained in other species suggests the possibiltity that O2‐free radicals be of minor importance in relation to brain aging in animals with low rates of oxygen consumption.