bluuebunny/crossref_metadata_2025_split huggingface dataset:
Binding properties, regional ontogeny and localization of adrenergic receptors in chick brain
Authors: Dermon C. R. , Kouvelas E. D. 
Published: April 2003

AbstractThe pharmacological properties of [3H]‐WB4101, [3H]‐clonidine and [3H]‐dihydroalprenolol binding in chick brain membranes display the characteristics known for α1‐, α2‐ and β‐adrenergic binding sites, respectively. Kinetic studies performed at different embryonic and post‐hatching ages have shown one binding component for each one of the above radioactive ligands.The ontogeny of α1, α2 and β binding sites was studied in cerebral hemispheres, optic lobes, brain stem and cerebellum. In all brain regions studied, the development of α2 binding sites precedes that of α1 and β, and a very significant decrease of α2 number was observed in the cerebellum, brain stem and optic lobes afterwards. The autoradiographic localization of adrenergic receptors was studied in the optic lobes and cerebellum. In the optic lobes the superficial layers of stratum griseum and fibrosum showed a strong selective labelling of α1, α2 and β binding sites and the strong selective labelling of α2 binding sites extended to the layer of stratum opticum. Among the nuclei located in the optic lobe only the nucleus mesencephalis lateralis pars dorsalis (MLD) exhibited a strong selective labelling for α1 binding sites while, for β binding sites, not only the MLD, but also the nucleus isthmic pars parvocellularis (Ipc) and the nucleus isthmic pars magnocellularisa (Imc) exhibited strong labelling. In the cerebellum strong selective labelling for α1 and β receptors was seen in the molecular layer. Labelling of the granule cell layer was almost equally strong for α1 but significantly less for β binding sites. No significant labelling could be detected for α2 binding sites.
Acetylcholinesterase in the development of chick dorsal root ganglia
Authors: Biagioni S. , Odorisio T. , Poiana G. , Scarsella G. , Augusti‐Tocco G. 
Published: April 2003

AbstractAcetylcholinesterase is expressed in chick dorsal root ganglia neurons very early in development. Since the physiological role of the enzyme in these cells is still obscure, it appeared of interest to investigate its modifications in the course of development.The specific activity of acetylcholinesterase in chick dorsal root ganglia increases, during in ovo development, from day E5 to day E13; after day E13 there is a decrease. Conversely, when acetylcholinesterase activity was expressed on a per ganglion basis, a continuous increase in the level of the enzyme until day E20 was observed.Acetylcholinesterase is a polymorphic enzyme and its molecular forms have different cellular localizations. Two globular forms, a tetramer (G4) and a dimer (G2), are present in the ganglia, as in chick brain. G4 is the major form at day E5, where it represents about 85% of the activity. This form shows a progressive decrease since day E8, and at day E20 exhibits activity levels similar to those of G2.It is known that acetylcholinesterase‐producing cells are also able to release the enzyme in the extracellular space. We determined the release of acetylcholinesterase by cultured dorsal root ganglia neurons at various developmental stages: acetylcholinesterase release is significantly increased at day E20, as compared to younger stages, and 90% of the enzyme released is G4.
Satellite cells in developing spinal ganglia. An immunohistochemical study
Authors: Lauriola Libero , Michetti Fabrizio , Coli Antonella , Bigotti Giulio , Cocchia Domenico 
Published: April 2003

AbstractThe present immunohistochemical study investigates the presence and distribution of S‐100‐containing glial cells in the early stages of development in human spinal ganglia. From the earliest ages investigated immunoreactive cells could be detected in a continuous layer at the periphery as well as inside ganglionic rudiments in close relationship with neural elements, both at the light and ultrastructural levels. The possibility that these glial cells, exhibiting such a distinctive distribution, play a modulatory role on microenvironmental influences during maturation could be taken into account. Neither glial fibrillary acidic protein nor myelin basic protein could be detected at the ages investigated.
Development and distribution of serotonin in the central nervous system of Manduca sexta during embryogenesis II. The ventral ganglia
Authors: Radwan Wafaa A. , Lauder Jean M. , Grange Noelle A. 
Published: April 2003

AbstractThe distribution of serotonin (5‐HT) immunoreactive cells and their projections was mapped in the ganglia of the ventral nerve cord of the tobacco hornworm, Manduca sexta, during embryonic development, using an antiserum to 5‐HT. Immunoreactive cells were first seen at 60% development. By 75% of embryonic development, a total of 94 immunoreactive cells were found in the ventral ganglia, including the suboesophageal ganglion. This number decreased to 80 neurons by 100% of development. About 50% of these cells were arranged in the abdominal ganglia and the rest were located in both the suboesophageal and thoracic ganglia. The suboesophageal ganglion exhibited immunoreactive segmentai interneurons in areas corresponding to the mandibular, maxillary and labial neuromeres. Two pairs of immunoreactive interneurons were also observed to occur bilaterally in each of the thoracic and abdominal ganglia, with the exception of the prothoracic ganglion. This ganglion contained three pairs of bilaterally arranged immunoreactive neurons as early as 60% of embryonic development. Serotonin immunoreactivity was also found in a number of efferent neurons in the mandibular and labial neuromeres of the suboesophageal ganglion and in the prothoracic, mesothoracic and posterior abdominal ganglia. The occurrence of 5‐HT in these efferent neurons suggests an involvement of serotonin in foreand hindgut function via its effect on the visceral muscles. Immunoreactive lateral longitudinal fibers extended along the entire length of the ventral nerve cord together with dense segmentai arborizations. The latter had regressed by the time the embryo was fully developed. This regression of the arborizations in the ganglia at the end of embryonic development indicates that a reorganization of 5‐HT innervation occurs to support new larval functions. The time of appearance of 5‐HT immunoreactive cells and fibers suggests that serotonin may play a role in the development of the ventral nerve cord.
Laminin and other basal lamina proteins with neurite promoting activity in medium conditioned by C6 glioma cells
Authors: Westermann R. , Mollenhauer J. , Johannsen M. , Unsicker K. 
Published: April 2003

AbstractNeurite promoting activities (NPFs) are essential factors in neuronal differentiation. Some of them are associated with proteins of the extracellular matrix (ECM). C6 cells, a rat glioma cell line, release NPF activities into the cell culture medium. We used antibodies against ECM‐proteins for enrichment and partial characterization of these activities. Results show that, (1) C6 cells express and release laminin; (2) the C6‐laminin consists of 260 kD chains only and is therefore different from typical basal lamina laminin (220 and 440 kD chains), but comparable to other laminins of glial origin (chains in the 200 kD range only); (3) C6‐laminin partially purified by affinity chromatography shows NPF‐activity; (4) laminin concentration in C6 cell‐conditioned medium is not sufficient to account for the total neurite promoting activity of the medium, and (5) in addition to laminin C6 cells express and release fibronectin and possibly type IV collagen.
Expression of muscle‐specific isozymes of phosphorylase and creatine kinase in human muscle fibers cultured aneurally in serum‐free, hormonally/chemically enriched medium
Authors: Pegolo Giovanna , Askanas Valerie , Engel W. King 
Published: April 2003

AbstractPrimary cultures of muscle cells derived from a biopsied adult human skeletal muscle were grown up to 6 weeks in a hormonally/chemically enriched serum‐free medium. The expression of musclespecific isozymes of creatine kinase, glycogen phosphorylase, and phosphoglycerate mutase, indicative of muscle cell maturation, was studied after 1,4 and 6 weeks of growth. The maturation of muscle fibers cultured in serum‐free medium was comparable to that achieved by muscle fibers cultured in medium containing 10% serum and supplemented with growth factors (insulin, epidermal growth factor, and fibroblastic growth factor) and was greater than that achieved in medium containing 10% serum only.Our study demonstrates that adult human muscle can be cultured aneurally for a long period of time in a serum‐free medium, and that it can achieve a high degree of maturation. This study provides an important basis for investigations related to: (1) assessment of the influence of individual components of the medium on human muscle maturation in culture; (2) studies of regulation of abnormal gene expression in diseased human muscle cultured in serum‐free medium.
Interactive effects involving different classes of excitatory amino acid receptors and the survival of cerebellar granule cells in culture
Authors: Balázs R. , Hack N. , Jørgensen O. S. 
Published: April 2003

AbstractDifferentiating granule cells develop survival requirements in culture which can be met by treatment with high K+ or N‐methyl‐d‐aspartate (NMDA) and, according to our recent findings, also with low concentrations of kainic acid (KA, 50 μM). We have now attempted to elucidate the mechanism(s) underlying the trophic effect of KA.KA rescue of cells was completely suppressed by blockers of voltage‐ sensitive calcium channels, such as nifedipine in low concentrations (5×10−7 M), indicating that the promotion of cell survival is mediated through the activation of these channels by membrane depolarization. Thus the trophic influences of KA and NMDA share a common mechanism, increased Ca2+ influx (albeit through different routes), a conclusion that is supported by the observation that the effects of these agonists at concentrations causing maximal promotion of cell survival were not additive.Interactive effects involving different classes of excitatory amino acid receptors were revealed by the potentiation of the KA rescue of cells by the NMDA receptor antagonists, 2‐amino 5‐phosphonovalerate (APV) or (+)‐5‐methyl‐10,11‐dihydro‐5H‐dibenzo[a,d]cyclohept‐5,10‐imine hydrogen maleate (MK‐801), which on their own failed to promote, but rather reduced cell survival. The potentiation of the KA effect by the competitive NMDA antagonist APV was counteracted by the weak NMDA agonist, quinolinic acid. These observations suggest that KA alone has both trophic and toxic effects, the latter being mediated secondarily through an NMDA‐like glutamate receptor, which is distinct from the conventional NMDA, KA and quisqualate preferring subtypes.
Taurine‐induced neuronal differentiation: the influence of calcium and the ganglioside gm1
Authors: Spoerri P. E. , Caple C. G. , Roisen F. J. 
Published: April 2003

AbstractTaurine‐induced differentiation was examined in the murine neuroblastoma Neuro‐2a cell line in the presence or absence of the monosialoganglioside GM1 and under conditions in which Ca2+ levels were manipulated. Taurine (4 mM), GM1 (200 μg/ml), or taurine with GM1 were applied to culture media that contained either various concentrations of Ca2+ or the Ca2+ ionophore A23187. Taurine or GM1 and taurine with GM1 increased the number of cells emitting neuntes above that found for controls. A significant interaction was found between treatment (taurine, GM1 or taurine+GM1) and the manipulations of Ca2+ levels, affecting the number of neuntes and producing changes on the neuritic and perikaryal surfaces. Treatment with both taurine and taurine+GM1 and the various concentrations of Ca2+ resulted in a significant increase in neurite elongation. The Ca2+ ionophore A23187 in the presence of taurine or taurine+GM1 caused neuntes to grow longer than observed in media containing Ca2+, either in a low concentration (about 125 μM) or at 1–2 mM. Taurine‐treated cultures in the presence of extracellular Ca2+ or A23187 were characterized by surfaces with numerous microvillar, spine‐like projections. This effect was enhanced with GM1 and was less pronounced in the medium containing low levels of Ca2+. Transmission electron microscopy of the taurine‐stimulated neurons revealed an excessive number of clear‐core vesicles (40–200 nm in diameter) in perikarya, neuntes and neuritic varicosities and growth cones. In addition, numerous aggregates of intermediate filaments were seen. They were most abundant in the taurine+GM1 treated cultures. The taurine+A23187 cultures also exhibited numerous microtubules within the elongated processes. The different neuritic patterns induced by taurine under conditions in which Ca2+ levels were manipulated and/or when cells were exposed to exogenous GM1 suggest that taurine's actions depend in part on Ca2+ flux.
Thyroidal stimulation of tubulin and actin in primary cultures of neuronal and glial cells of rat brain
Authors: De Arunangsu , Chaudhury Sukanya , Sarkar Pranab Kumar 
Published: April 2003

AbstractThe influence of triiodothyronine (T3) on the level of tubulin and other proteins in primary cultures of neuronal (N) and glial (G) cells from rat brain has been investigated. Quantitation of tubulin by [3H]colchicine binding assay revealed that when cells from 1 day rat brain were cultured for 18 hr with physiological doses (0.5–5 nM) of T3, the hormone elicited 35–40% increase in the soluble (30,000 g supernatant) tubulin content of G cells only. This stimulation was age‐dependent and occurred neonatally at a time corresponding to the onset of synaptogenesis. In mouse and chick brain also, [3H]colchicine binding assay showed a similar selective stimulation of the soluble tubulin content of G cells by T3 with virtually no effect on N cells. However, SDS‐polyacrylamide gel electrophoresis of the total proteins in the 30,000 g supernatants from N and C cells of rat brain, labeled for 18 hr with [14C]leucine in the presence of T3, revealed that T3 elicited 2–3‐fold enhancement of radiolabeled tubulin in the N cells which is relatively greater than the 1.5‐fold increase seen in the G cells. Analysis of the autoradiograms of these labeled proteins also revealed that in addition to tubulin, T3 stimulated the accumulation of radiolabeled actin by 1.5‐ and 2‐fold in N cells and G cells respectively. Similar electro‐phoretic analysis of the solubilized labeled proteins in the 30,000 g pellets from N and G cells indicated that the failure to detect the stimulation of tubulin in the 30,000 g supernatants from N cells by [3H]colchicine binding assay could be at least partly due to rapid translocation of the dimeric soluble tubulin into insoluble membrane fractions or due to presence of higher oligometric forms of tubulin which are insensitive to [3H]colchicine binding assay.
An immunohistochemical study of neurotransmitter profiles in developing human visual cortex
Authors: Masood Farzana , Wadhwa Shashi , Bijlani Veena 
Published: April 2003

AbstractThe temporal pattern of development and distribution of gamma aminobutyric acid, serotonin, substance P and neuropeptide Y immunoreactive profiles was studied in the human visual cortex from 16 to 26 weeks of gestation, using an immunohistochemical technique. The immunoreactive profiles showed an increase in number and a change in their morphology and distribution pattern over the time period studied. A large number of neurons, fibers and terminals were stained with GABA antibody at 17–18 weeks and were distributed throughout the five zones of the developing visual cortex. GABA neurons were non‐pyramidal and bipolar in form at 17–18 weeks while at 18–19 and 20–21 weeks the cells of subplate and intermediate zones were multipolar. Substance P and serotonin immunopositive fibers were present mainly in the intermediate zone at 16 and 17–18 weeks, where they were oriented in a horizontal manner. At subsequent ages they invaded the other zones also. Substance P positive neurons could be visualized only at 26 weeks of gestation in the intermediate, subventricular and ventricular zones; no cell bodies, however, stained with serotonin antibody. Neuropeptide Y immunoreactive cells and fibers were first seen in the intermediate zone but later were found to be distributed in other zones too. The observations indicate that the intermediate zone of the visual cortex in which the transmitters and peptides appear earlier assumes importance in the normal development as also noted in other mammals.
Butyrylcholinesterase activity in the developing auditory brainstem, the choroid plexus and the pituitary of the perinatal rat
Authors: Krupnik Eduardo , Paterson J.A. 
Published: April 2003

AbstractThe butyrylcholinesterase activity in the vasculature of the brain, choroid plexus, and pituitary, was studied histochemically in rats during postnatal days 1,7,14,21 and 28. The brainstem auditory nuclei were used for comparison of vessels at different ages. We found intense butyrylcholinesterase activity in all intraparenchymal blood vessels, especially capillaries, in all ages. In the meningeal vessels, activity was especially prominent in 1 and 7 day old animals when the perineural meninges was relatively thick. In the pituitary, reaction for the enzyme was found in nonvascular elements, especially in the intermediate and posterior lobes. Vessels of the choroid plexus were associated with punctate regions of butyrylcholinesterase activity. These results do not support the suggestion of a major role for butyrylcholinesterase in the blood‐brain barrier.
Histochemical study by lectin binding of surface glycoconjugates in the developing olfactory system of rat
Authors: Franceschini Valeria , Lazzari Maurizio , Revoltella Roberto Paolo , Ciani Franco 
Published: April 2003

AbstractLectin‐binding histochemistry was used to investigate the distribution and density of defined carbohydrate sequences on the cell surface glycoproteins of the olfactory receptors of rat during development. The olfactory and vomeronasal receptors showed a positive labelling after biotinylated Lycopersicum esculentum lectin binding on embryonic day 16 (E16), while horseradish peroxidase‐labelled Glycine max, Bandeiraea simplicifolia (BS A‐I) and its B4 isomer BSA‐I‐B4 agglutinins started to label from day 18 (E18). From this stage onward there was a progressive increase in the intensity and number of lectin‐binding olfactory receptors. The first lectin‐labelled bundles of axons penetrating the olfactory bulb were observed on E20; from E21 it was possible to identify the first labelled glomeruli that, on the first day (P1) of postnatal life, showed a feature very similar to that of the adult. The lectin staining patterns indicate that during development there are differences in the kind and distribution of saccharidic moieties on the surface of rat olfactory neurons. The possible role of carbohydrate‐containing glycoproteins in the reception and transduction of the odours and in the modulation of the cell‐cell interactions in the olfactory system is discussed.
Serum factors and hydrocortisone influence the synthesis of myelin basic proteins in mouse brain primary cultures
Authors: Byravan Sujatha , Campagnoni Anthony T. 
Published: April 2003

AbstractMouse brain primary cultures were used to study the influence of serum factors and hydrocortisone on myelin basic protein (MBP) gene expression. Serum factors increased the synthesis of the MBP isoforms in 18‐day and older cultures. Synthesis of the 17 and 18.5 kDa MBPs steadily increased from 14 to 26 DIV (daysin vitro). Synthesis of the 14 kDa MBP reached a peak at 22 days, after which it fell off rapidly. Addition of serum to the medium also stimulated MBP mRNA expression. However, in the presence of serum, maximal stimulation of MBP mRNA expression occurred at 16–20 days, significantly earlier than maximal stimulation of 17 and 18.5 kDa MBP synthesis by serum. These observations suggest that serum influences both transcriptional and post‐transcriptional steps in the expression of the MBP genes in primary cultures. Hydrocortisone increased the synthesis of the 14,18.5 and 17 kDa MBP isoforms by two‐ to three‐fold. This effect was seen in cultures older than 15 DIV. This effect of hydrocortisone on the synthesis of the MBPs may be responsible for the increase in the steady state levels of MBP in the presence of hydrocortisone. These studies suggest a role for serum factors and hydrocortisone in the transcriptional and post‐transcriptional steps of MBP gene expression. They also suggest that this role may be developmentally regulated.
Involvement of conserved asparagine and arginine residues from the N‐terminal region in the catalytic mechanism of rat liver and Trypanosoma cruzi tyrosine aminotransferases
Authors: Sobrado Verónica R. , Montemartini‐Kalisz Marisa , Kalisz Henryk M. , de la Fuente María Candelaria , Hecht Hans‐Jürgen , Nowicki Cristina 
Published: April 2003

AbstractRat liver and Trypanosoma cruzi tyrosine aminotransferases (TATs) share over 40% sequence identity, but differ in their substrate specificities. To explore the molecular features related to these differences, comparative mutagenesis studies were conducted on full length T. cruzi TAT and N‐terminally truncated rat TAT recombinant enzymes. The functionality of Arg315 and Arg417 in rat TAT was investigated for comparison with the conserved Arg292 and Arg386 in aspartate and bacterial aromatic aminotransferases (ASATs and ARATs). The rat TAT Arg315Lys variant remained fully active indicating that, as in T. cruzi TAT and contrary to subfamily Iα aminotransferases, this residue is not critical for activity. In contrast, the Arg417Gln variant was inactive. The catalytic relevance of the putative rat TAT active site residues Asn54 and Arg57, which are strictly conserved in TATs (Asn17 and Arg20 in T. cruzi TAT) but differ in ASATs and ARATs, was also explored. The substitutions Arg57Ala and Arg57Gln abolished enzymatic activity of these mutants. In both variants, spectral studies demonstrated that aromatic but not dicarboxylic substrates could efficiently bind in the active site. Thus, Arg57 appears to be functionally equivalent to Arg292 of ASATs and ARATs. Asn54 also appears to be involved in the catalytic mechanism of rat TAT since its exchange for Ser lowered the kcat/Km ratios towards its substrates. Mutation of the analogous residues in T. cruzi TAT also lowered the catalytic efficiencies (kcat/Km) of the variants substantially. The results imply that the mamalian TAT is more closely related to the T. cruzi TAT than to ASATs and ARATs.
The X-Trials: Neural Correlates of an Inhibitory Control Task in Children and Adults
Authors: Davis Elysia Poggi , Bruce Jacqueline , Snyder Kelly , Nelson Charles A. 
Published: April 2003

Abstract
Event-related potentials (ERPs) were used to examine developmental differences between adults and 6-year-old children in the neural processes involved in an inhibitory control task. Twenty adults and 21 children completed a task that required them to selectively respond to target stimuli while inhibiting responses to equally salient non-target stimuli. Because this task had been previously studied using functional magnetic resonance imaging (fMRI), the relation between the fMRI and ERP findings was informally examined. The results indicate that latency and amplitude of the P3 differentiated the different types of trials. However, the pattern of event-related neural activity differed for adults and children. These results, which suggest that adults and children may be using different processes to perform this task, have implications for the interpretation of the previous fMRI findings.