bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of opiates on the growth of neuron‐enriched cultures from chick embryonic brain
Authors: Sakellaridis Nikos , Mangoura Dimitra , Vernadakis Antonia 
Published: April 2003

AbstractNeuron‐enriched cultures derived from 6‐day‐old chick embryo cerebral hemispheres were treated with morphine or methadone, 10−5 M or 10−6 M, on days 4–6 or 6–8 in culture and were evaluated morphologically and biochemically at day 9 using phase contrast microscopy and choline acetyltransferase activity (ChAT) as a cholinergic marker. The treatment of the cultures with morphine markedly affected their growth pattern; specifically, we observed an increased number of flat cells presumptively glia, and aggregates sided by flat cells and devoid of thick bundles of neuritic processes that normally characterize neuron‐enriched cultures. These morphologic changes were reflected in a drastic decrease of ChAT activity in cultures treated from day 4 to day 6 but not from 6 to 8. In contrast to morphine, exposure to 10−6 M methadone from day 4 to day 6 resulted in reduced ChAT activity but the growth pattern of the cultures remained morphologically intact. We suggest that morphine exerts a general neurotoxic effect whereas methadone may affect some specific cholinergic function.
Sex differences in nerve growth factor levels in superior cervical ganglia and pineals
Authors: Wright L. L. , Beck C. , Perez‐Polo J. R. 
Published: April 2003

AbstractThe current studies were undertaken to determine whether males or neonatally testosterone‐treated rats of either gender have elevated endogenous levels of NGF in the SCG and one of its targets, the pineal gland. The ages studied were 5 days postnatal, which is at the peak of normal neuron death in the SCG but before a significant gender difference is present; 15 days, when normal neuron death is largely complete and males have more SCG neurons than females; and 30 days, when target innervation has matured.At 5 days, while neuron death is occurring, but before there is a significant gender difference in neuron number in the SCG, pineal glands and SCGs of males had higher NGF content than those of females. The increased NGF in the ganglia of males at the time that these neurons are undergoing neuron death may play a role in the development of the sex difference in SCG neuron numbers. At 15 days, females had more NGF in their pineal glands and SCGs than did males, even though males have significantly more SCG neurons at this age than do females. This gender difference in the developmental course of NGF content could promote the survival of different populations of neurons in males and females. By 30 days, SCG and pineal NGF content of males was almost twice that of females. This is consistent with the presence of more neurons in the SCGs of males at this age.Both the pineal gland and the SCG showed a loss of approximately 80% content of NGF during the first postnatal month. In males, this loss occurred between postnatal days 5 and 15, while in females, the drop in NGF content occurred between postnatal days 15 and 30. Treatment with testosterone from birth reduced NGF content in the SCGs of both males and females at 5 days of age. The depression of NGF levels by testosterone treatment may reflect a further acceleration of the developmental fall of NGC levels.
Effects of triiodothyronine on the development of GFAP‐immunoreactivity and cat‐activity in monolayer cultures of embryonal rat forebrain cells
Authors: Madarász Emilia 
Published: April 2003

AbstractDose‐dependent actions of triiodothyronine were studied in serum‐containing primary cultures of embryonal rat forebrain cells. Triiodothyronine at concentrations exceeding the normal medium concentration by 2 and 5 nM failed to cause significant changes in the development of CAT‐activity and GFAP‐immunoreactivity. In the presence of additional 10 and 20 nM T3, however, CAT‐activity was increased and GFAP‐immunoreactivity was decreased in comparison to cultures maintained with ‘normal’ (10% FCS‐containing) media.
Correlation of clustering peak density and total amount of acetylcholine receptor on cultured mouse myotubes
Authors: Shikada K. , Kimura I. , Kimura M. 
Published: April 2003

AbstractThe development of acetylcholine receptor (AChR) and its clustering were studied quantitatively on mouse myotubes in nerve‐muscle co‐cultures. AChR was visualized by fluorescence‐labeled antibodies (F‐Ab) against crude AChR or fluorescence‐labeled α‐bungarotoxin (F‐α‐BuTX). The F‐Ab stain was observed throughout the entire surface of the myotube at day 8 and appeared clustered at day 13. Both peak density and total amount of fluorescence in F‐Ab stained myotubes were plotted against days in culture. Both fluorescence indices markedly increased from days 8 to 13 of culture were greater in extent in myotubes incubated in the presence of spinal cord explant, as compared with its absence. Similar results were observed in myotubes stained with F‐α‐BuTX. d‐Tubocurarine (d‐TC, 0.1 mg/ml) and native α‐BuTX (1 μg/ml) clearly inhibited both the total amount of fluorescence and the development of peak fluorescence density in the F‐Ab stained myotubes. But the inhibition by d‐TC appeared at the later day in culture than α‐BuTX did. Low temperature (28°c) and cholesterol (1 μg/ml) treatment inhibited peak fluorescence density without affecting total amount of fluorescence. These results show that the development of ACh can be characterized both by clustering peak density (indicating the lateral mobility of AChR) and by total amount of fluorescence.
Development of serotoninergic neurons from ventricular cells of the mouse neural plate in vitro
Authors: Buse Eberhard 
Published: April 2003

AbstractCephalic neural plates and neural tubes of mice (pros‐ and rhombencephalic anlagen), developmental stages Theiler 11–18 [Th 11–18; embryonic day –11 (E–11)], were prepared and cultured in a plasma clot with horse serum‐containing MEM medium. Differentiation of the ventricular cells was studied in order to investigate the expression of serotoninergic properties. Serotoninergic neurons were not detected in preparations derived from neural plates of stage Th 11 (E), but were demonstrated in increasing numbers from the early stage Th 12 (E8) onwards. They exclusively originated from the rhombencephalic floor caudal to the mesencephalic flexure. The serotoninergic neurons developed from these areas, irrespective of whether being cultured in their natural position within the neural plate, or separated as microcultures, or transplanted into the prosencephalic anlage. Every other region of the neural plate remained free of serotoninergic neurons.The in vitro findings are highly reproducible due to the following properties: the morphological and immunocytochemical peculiarities of the serotoninergic neurons, their tendency to appear in increasing numbers with age, their localization within the cultured neural plates and their appearance in all cultures from stage Th 12 (E8) on. Due to these findings it is considered possible that the progenitor cells of serotoninergic neurons might already have been determined within distinct areas in the mouse neural plates as early as stage Th 12 (E8).
Ganglioside potentiation of NGF‐independent conditioned medium enhancement of neuritic outgrowth from spinal cord and ciliary ganglia explants
Authors: Spoerri P. E. , Roisen F. J. 
Published: April 2003

AbstractCulture medium conditioned (CM) by embryonic chick skeletal muscle or RN22 Schwannoma cells enhanced dramatically the neuritic development of chick embryonic spinal cord slices explanted onto a collagen substratum. The addition of a mixture of bovine brain gangliosides (BBG) or the monosialoganglioside GM1 to this medium potentiated the nerve growth factor (NGF)‐independent CM‐mediated neuritogenesis. A 3–4 fold increase in spinal cord outgrowth was due to increased neurite number, length and branching. The ability of the gangliosides to potentiate the positive neuritogenic action of CM was not limited solely to spinal cord cultures since similar results were obtained in parallel studies employing organized cultures of embryonic chick ciliary ganglia. These studies demonstrate the ability of gangliosides to enhance the trophic action of factor(s) present in CM. They suggest further that gangliosides may play a modulatory role in the development of the nervous system.
Ultrastructural study of calycine synaptic endings of colossal vestibular fibers in the cristae ampullares of the developing chick
Authors: Peusner Kenna D. , Lindberg Nancy H. , Mansfield Paul F. 
Published: April 2003

AbstractBipolar vestibular ganglion cells give rise to the colossal vestibular fibers in the chicken. These fibers form the largest calycine endings in the cristae ampullares and also the spoon endings in the tangential vestibular nucleus of the medulla oblongata. Because these synaptic endings are two of the largest and most distinctive in the vertebrate nervous system, they are especially suitable for comparisons of the development of synapses and synaptic endings of a specific cell type. An ultrastructural study of the spoon endings and quantitative data on their synapses were available from material of 15‐day‐old chick embryos, hatchlings, and 3‐yr‐old chickens. Here we provide similar data on the large calyces. Briefly, large calyces exhibited no ultrastructural changes corresponding to the changes in the spoon endings apparent when they retract from their target cell surfaces around hatching time. However, the concentration of the ribbon synapses at the large calyces decreased around hatching, when the concentration of the chemical synapses at the spoon endings declined. Moreover, the concentration of the ribbon synapses at the large calyces corresponded closely to the concentration of the chemical synapses at the spoor endings at the same age. Thus at the developmental ages studied, there were similar concentrations in the peripheral and central synapses formed at two different synaptic endings, both derived from one cell type and participating in the same neural pathway.These findings raise the issue of how synapses are regulated locally, but also suggest the possibility for central‐peripheral interactions to produce correlative changes in parallel.
Ontogenetic changes in the level and subcellular distribution of protein kinase C in cat visual cortex
Authors: Stichel C. C. 
Published: April 2003

AbstractOntogenetic changes of the total activity and the subcellular distribution of Ca2+‐activated, phospholipid‐dependent protein kinase (protein kinase C) were investigated in the cat visual cortex.Following homogenization of the tissue in Ca2+‐free buffer and separation of membrane‐bound and soluble protein kinase C, the enzyme was partially purified by diethylaminoethyl‐cellulose chromatography. Total, membrane‐bound and soluble enzyme activity were determined by measuring the phosphate incorporation into lysine‐rich histone, a substrate for protein kinase C.It was found that the total activity level, while being low in the first 4 weeks, increased rapidly to peak values at 5 weeks of age and declined slightly thereafter. Although at all developmental stages most of the enzyme was recovered in the soluble fraction, the membrane‐bound activity exhibited a considerable increase at 5 weeks of age, reflecting a relative shift of protein kinase C from the cytosol to the membranes.The increase and redistribution of protein kinase C activity coincide in time with the developmental phase during which the visual cortex is particularly susceptible to undergo use‐dependent modifications. This finding is compatible with the hypothesis that protein kinase C‐mediated phosphorylation processes are involved in activity‐dependent modifications of neuronal transmission.
A morphological and biochemical study of the myelin‐like membrane structures formed in cultures of pure oligodendrocytes
Authors: Nussbaum J. L. , de los Monteros A. Espinosa , Pari F. M. , Doerr‐Schott J. , Roussel G. , Neskovic N. M. 
Published: April 2003

AbstractThis study reports the production of myelin‐like membranes in oligodendrocyte subcultures derived from 20‐day‐old primary glial cell cultures of newborn rat brain. These multi‐layered structures show a variable number of membrane turns; up to 10 concentric lamellae are found in 3‐ to 4‐week‐old subcultures. When they are compacted, alternate dense and intraperiodic lines with a periodicity of 11.2 nm are noticeable. The most typical myelin proteins were detected straight on the multi‐lammellar structures by a gold immunocytochemical method. Subcellular fractions containing these myelin‐like structures were isolated by ultracentrifugation on a discontinuous sucrose gradient. They were analysed by sodium dodecylsulfate‐polyacrylamide gel electrophoresis and immunoblotting; UDP‐galactose: ceramide galactosyltransferase and 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase activities were also measured.The results indicate that the multi‐layered membrane profiles have many characteristics of the myelin found in vivo; nevertheless some differences were still apparent. Our data support the concept of the cultured oligodendrocytes expressing the intrinsic myeltnogenic properties and possessing a basic developmental program of myelination, apparently in the absence of stimuli coming from other brain cells.
Cytodifferentiation and developing neuronal circuitry in the human lateral geniculate nucleus
Authors: Wadhwa Shashi , Bijlani Veena 
Published: April 2003

AbstractThe developing neural substrate in dorsal lateral geniculate nucleus of human fetuses and premature, full‐term and postnatal infants, has been analysed using rapid Golgi impregnation, computerized image analysis, electronmicroscopy, and immunocytochemical method for localization of γ‐aminobutyric acid. Nuclear and cytoplasmic neuronal maturation is observed to extend over the entire period studied. Axodendritic synapses, presumably of retinal origin, are occasionally seen at 13–14 fetal weeks. They become increasingly apparent at 18–19 weeks. Dendrodendritic contacts are visualized at 15 weeks. Cortical terminals and occasional triadic contacts are evident around 21 weeks. The inhibitory interneurons containing γ‐aminobutyric acid are present in small numbers at 15–16 weeks; their numerical density increases considerably at 17 weeks but decreases thereafter. The presence of γ‐aminobutyric acid containing nerve cells and synaptic triads is indicative of the formation of inhibitory circuitry. At 15–16 weeks neurons are mostly bipolar although different forms of multipolar cells may be seen. By 24 weeks the radiated and bitufted multipolar neurons, neurons with beaded dendrites and neurons with axon‐like dendritic processes are identifiable. There are no apparent differences in differentiation of neurons between the cranial and caudal parts of dorsal lateral geniculate nucleus. At 15–16 weeks, however, the cells of prospective magnocellular zone appear to be more mature than do the cells in the parvocellular zone. The neuronal soma increases continuously in size. Dendrite development starts at 15–16 weeks of gestation, thereafter the increase in number of their branches and their length is observed. Between 15–16 and 24 weeks, spines and filiform processes appear first on the proximal shafts of the dendrites and subsequently on their distal portion. There is increase in the number of filiform processes and hair‐like appendages on geniculate neurons of premature infants born at 32 and 37 weeks of gestation and of a 4‐day postnatal infant. Computerized quantitative data substantiate the progressive increase in growth parameters. The significance of comparative and functional aspect of the data is discussed.
Udpgalactose:Ceramide galactosyltransferase in cultured oligodendrocytes: An enzymological and immunological study
Authors: Neskovic Nenad M. , de los Monteros Araceli Espinosa , Roussel Guy , Nussbaum Jean‐Louis 
Published: April 2003

AbstractThe developmental expression of UDPgalactosexeramide galactosyltransferase (CGalT), an enyme marker of one myelinogenic activity in nervous tissue, was studied in cultured oligodendrocytes. The activity of CGalT in cultures followed a characteristic pattern of developmental changes. In the primary cultures these changes could be represented by a biphasic curve with a maximum of enzymatic activity at about the 25th day in culture. After purifying the oligodendrocytes from the primary cultures and replating them in culture dishes, similar developmental changes of CGalT were observed. In the subultures prepared from 20‐day‐old primary cultures the activity of CGalT per oligodendrocyte increased from 1.3 × 10−6 nmol/hr on day 4 to 3.7 × −6nmol/hr on day 21. Immunocytochemical studies with the antiserum against rat brain CGalT showed the presence of CGalT+ oligodendrocytes after 7 days in the primary culture (earliest time studied), later on the number of CGalT+ oligodendrocytes increased until 28 days (latest time examined). In the subcultures of purified oligodendrocytes the bulk of oligodendrocytes was stained by the anti‐CGalT antibodies after 15 days. These results suggest that the initial expression of CGalT in oligodendroglial cultures involves an increase of the number of CGalT+ oligodendrocytes and of the amount of enzyme protein per cell.
Catecholaminergic cells and support cell precursors in neural crest cultures differentially express nerve growth factor receptors
Authors: Bernd Paulette 
Published: April 2003

AbstractLong‐term neural crest cultures grown in the continuous absence of exogenous nerve growth factor (NGF) contain a subpopulation of cells with NGF receptors exclusively of the low affinity subtype (d of approximately 3.2 nM). The current studies combined immunocytochemistry, using GIN1 (a support cell marker) or tyrosine hydroxylase antibodies, with radioautography following exposure to iodinated nerve growth factor (125I‐NGF). The majority of cells specifically binding 125I‐NGF were found to be immunoreactive for GIN1, indicating that the primary cell phenotype expressing receptors for NGF appear to be support cell precursors, at least under these conditions. These cells are likely to be responsive to and/or dependent upon NGF; the nature of this response or dependency remains to be determined. Some cells exhibiting silver grains were not immunoreactive for GIN 1, suggesting that other cell phenotypes in neural crest cultures also have NGF receptors. In addition, some neural crest cells were found that stained with GIN1 and lacked 125I‐NGF binding. Tyrosine hydroxylase‐like immunoreactive cells apparently did not bind 1251‐NGF under these culture conditions. Catecholaminergic sympathetic and sensory neurons from embryonic ganglia, derived from the neural crest, express both the high and low affinity forms of the NGF receptor. In order to determine whether the microenvironment played a role in the type of Catecholaminergic cells appearing in culture, neural crest cells were grown in the continuous presence of exogenous NGF. Under these conditions, many tyrosine hydroxylase‐like immunoreactive cells were found that specifically bound 125I‐NGF. In addition, silver grains were still detected on these cells following a chase with nonradioactive NGF, designed to eliminate 125I‐NGF bound to low affinity sites. Therefore, the Catecholaminergic cells possess both the low and high affinity forms of the receptor. NGF's ability to modulate tyrosine hydroxylase activity, as it does in mature Catecholaminergic neurons, was tested in this system. Surprisingly, there was no statistically significant difference in tyrosine hydroxylase activity in cultures grown in the absence or presence of exogenous NGF. This raises the possibility that embryonic Catecholaminergic cells are unable to respond to NGF in this specific way, even though the receptors for the factor are present.
Selective effects of thyroid hormonal deprivation on growth and development of olfactory receptor sheet during the early postnatal period: A morphometric and cell count study in the rat
Authors: Paternostro Mark , Meisami Esmail 
Published: April 2003

AbstractLight microscopic numerical and morphometric studies were conducted on the olfactory epithelium of postnatal normal and hypothyroid rats. The normal rat olfactory epithelium undergoes marked growth and development during the suckling period (days 1–25): thickness, 50%; area, × 8, total number of olfactory neurons, basal and supporting cells, × 10, × 11 and × 8, respectively. The effects of thyroid hormonal deprivation on these proliferative postnatal growth changes were studied by adding PTU (n‐propylthiouracil, a reversible antithyroid goitrogen) to the litter's drinking water from birth to weaning (day 25).The general architecture of naso‐olfactory cavities as well as the histology and thickness of the olfactory epithelium were unaffected in the hypothyroid pups. However, the surface area of the olfactory receptor sheet was reduced by 40%, the reduction occurring throughout the cavity, though not uniformly. The total number of olfactory neurons, supporting and basal cells were reduced by 33, 45 and 47%, respectively. These results indicate that the postnatal vertical accretion of olfactory neurons occurring across the epithelial thickness is unaffected in the hypothyroid pups, while the horizontal proliferation of neurons accompanying the expansion of the sheet's surface area is markedly reduced. The results suggest differential effects of thyroid hormones on these modes of proliferative growth and imply further that in addition to possible direct effects, the influence of thyroid hormones on developmental growth of the olfactory epithelial sheets may be secondary to effects on the underlying submucosal connective tissue.
The time course of hippocampal cholinergic innervation in the developing hypothyroid rat. A combined histochemical and biochemical study of acetylcholinesterase activity
Authors: Rami Abdelhaq , Rabie Alain , Clos Jean 
Published: April 2003

AbstractDevelopment of cholinergic innervation in the hippocampal formation of normal and hypothyroid rats was studied by a combined biochemical and histochemical analysis of acetylcholinesterase (AChE) activity in normal and hypothyroid rats. The normal developmental pattern of cholinergic activity suggests an entrance of septal cholinergic fibers from the fimbria to different zones of the hippocampal formation mainly during the first postnatal week. By 10 days of age, the regional distribution of staining was similar to that in the adult. Thereafter, the intensity of staining increased without major changes in the laminar organization. As shown by closely related histochemical and biochemical findings, hypothyroidism led to a delay in the arrival of cholinergic afferences and a possible subsequent cholinergic hyperinnervation of the hippocampal formation in adulthood. These results are discussed taking into account the time course of structural development in the two synaptic compartments, namely the extrinsic septal neurons and intrinsic pyramidal and granule cells, in comparison with the development of thyroid function.