bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dopamine‐β‐hydroxylase‐like immunoreactivity in the fetal cerebral cortex of the rat: Noradrenergic ascending pathways and terminal fields
Authors: Verney Catherine , Berger Brigitte , Baulac Michel , Helle Karen B. , Alvarez Chantal 
Published: April 2003

AbstractA topographical analysis of the noradrenergic innervation in the fetal rat cerebral cortex was carried out from embryonic day 15 (E15) until birth using antibodies raised against dopamine‐β‐hydroxylase (DBH). During late gestation DBH‐like immunoreactive axons were coursing through the basal forebrain along three pathways: (1) a medial component reached the medial cortex and then ran caudally along the anlage of the cingulum bundle; (2) a lateral component reached the frontal pole and curved ventro‐dorsally in the primordium of the external capsule; (3) a few fibers were observed along the ventral amygdaloid bundle toward the amygdaloid complex and the surrounding cortex. No DBH positive fibers were observed in the main body of the internal capsule.The first noradrenergic axons were seen at E17 in the frontal pole, the lateral frontal cortex, and in the medial frontal cortex which also receives a dopaminergic input. The innervation then extended caudally, but the dorsal part of the cortex was reached after a 2‐day delay when compared to the medial and lateral parts. The arrival of noradrenergic axons did not parallel the gradient of cortical neurogenesis; however, all cortical areas were innervated at birth. DBH positive fibers reached a given cortical region simultaneously through the marginal and intermediate zones and then invaded the cortical plate.
The ontogenesis of the dopaminergic cell in the pre‐ and postnatal guinea pig retina
Authors: Parkinson David , Spira Arthur , Wyse J. Patrick , Patten Marilyn 
Published: April 2003

AbstractWe have examined the development of the dopaminergic system of the guinea pig retina, a species in which retinal neuronal and synaptic differentiation occurs largely in utero. Fetal animals aged 42–69 days (full term), neonates, postnatal (pn) animals to 12 weeks, and mature animals were studied to determine retinal dopamine (DA) storage, metabolism (DOPAC), in vitro tyrosine hydroxylase (TH) activity, postsynaptic target activation (cAMP stimulation) and localization (formaldehyde‐induced histofluorescence). DA‐stimulated adenylate cyclase at 42 days of gestation was threefold over basal activity, preceding the onset of the accumulation of DA and DOPAC at 45 days, and the initial localization of DA in cell perikarya at 47 days and in processes at 50 days. At birth DA and DOPAC levels were 45 and 37%, respectively, of adult levels. DA levels remained stable during the first few days pn, although in vitro TH activity was capable of stimulation by light in the neonate as in the mature animal. DA and TH activity increased from 1 week pn to reach adult levels by 10 weeks pn. Although a significant degree of development of the dopaminergic neurotransmitter system in the guinea pig occurs before birth the attainment of a fully mature system postnatally may require normal photic stimulation of physiologic activity.
Postnatal development of calmodulin and calmodulin‐dependent phosphodiesterase in different regions of the rat central nervous system
Authors: Toro M.J. , Salinas‐Fando M. , Montoya E. 
Published: April 2003

AbstractWe have studied the concentration of calmodulin and phosphodiesterase (cAMP high Km) in five different parts of the rat central nervous system (hemispheres, cerebellum, diencephalon, brain stem and spinal cord) during postnatal development (5, 10, 15, 20, 30 and 45 days after birth). The concentration of the enzyme and its regulatory protein were independent, so that no correlation could be established between them. In most structures, calmodulin concentration tended to decrease with age, while phosphodiesterase increased or remained at similar values during the time studied.The calmodulin inhibitor trifluoperazine, inhibited phosphodiesterase activity to different degrees, depending on the structure, and age. Hemispheres, diencephalon and brain stem showed maximal inhibition (approximately 95‐65% of control). In these structures, inhibition was higher in older animals. By contrast, cerebellum and spinal cord PDE was less inhibited by trifluoperazine (65‐50% of control), and inhibition was independent of age. The validation of a method for both calmodulin and phosphodiesterase assay, using a modification of established methods, is also reported.
Oxidative metabolism in cultured astroglial cells from rat brain
Authors: Peterson Anders , Odland Lena , Sensenbrenner Moniqiue , Walum Erik 
Published: April 2003

AbstractCirowth, morphology, glutamine synthetase activity, eytoehrome C oxidase activity and respiratory activity of rat brain cultures enriched in astrocytes were studied during four weeks in culture. Two different polarographic methods were used for measurement of respiratory activity: one newly developed perfusion method leaving the cellular monolayer morphologically intact and still attached to the culture dish, and one traditional stirring method involving the removal of cells from the culture vessel. Regardless of the method used, a stable respiratory activity was registrated throughout the four weeks of culturing. Also the eytoehrome C oxidase activity remained unchanged. In perfusion all absolute values for respiration were found to be higher than those obtained with the stirring method. The use of the stirring technique resulted in a doubling of oxygen consumption upon succinate addition. No such effect was seen in perfusion. It can thus be concluded that the removal of cultured astrocytic cells from their substratum alters their respiratory activity and their response to added substrates.
Transient expression of 5‐HT1A receptor binding sites in some areas of the rat CNS during postnatal development
Authors: Daval G. , Vergé D. , Becerril A. , Gozlan H. , Spampinato U. , Hamon M. 
Published: April 2003

AbstractThe developmental evolution of 5‐HT1A receptor binding sites was examined in the rat CNS during the early postnatal period using quantitative autoradiography and binding assays with 3H‐8‐OH‐DPAT as the selective ligand. A progressive increase in the density of 5‐HT1A sites was observed in the hippocampus, septum and cerebral cortex, up to adult levels which were reached around the third postnatal week. In contrast, complex biphasic (increase then decrease) changes were noted in other structures (for instance the nucleus of the lateral lemniscus) and even a progressive decrease in the density of 5‐HT1A sites took place in the cerebellum during the first two postnatal weeks. The transient expression of 5‐HT1A receptor binding sites in a structure such as the cerebellum which develops exclusively for the postnatal period further supports that 5‐HT might play a trophic role during maturation of the CNS.
Messenger RNAs of β‐amyloid precursor protein and prion protein are regulated by nerve growth factor in PC12 cells
Authors: Wion Didier , Le Bert Marc , Brachet Philippe 
Published: April 2003

AbstractThe effect of the neurotrophic factor NGF on the expression of two genes involved in the accumulation of amyloid deposits in neurodegenerative disorders was studied in a clonal cell line, PC12. Use of hybridization methods showed that NGF increased the cellular pool of the mRNA of the prion protein, a macromolecule known to generate fibrillary aggregates in the brain of scrapie‐infected animals. Maximal levels of prion mRNA were obtained after 7 days of treatment, but a significant increase was already detectable after 48 hr of exposure to NGF. In contrast, the factor did not increase the cellular content of the transcripts coding for the precursor of the β‐amyloid peptide (APP), which participates in the formation of neuritic plaques in human brains affected by Alzheimer's disease. However, NGF caused a drop in the molecular weight of that mRNA. This change, which is likely to result from a loss of 100–200 bp, was already detected after 24 hr of treatment. These results indicate that NGF induces in target neuronal cells a quantitative and a qualitative modification of the transcription products encoding two different amyloid precursor proteins.
Development of postsynaptic‐like specializations of the neuromuscular synapse in the absence of motor nerve
Authors: Sohal G. S. 
Published: April 2003

AbstractIt was previously reported that the acetylcholine receptor clusters and acetylcholinesterase appear on embryonic superior oblique muscle cells developing in vivo without motor nerve contacts. The objective of this study was to examine whether some other components of neuromuscular junction also form on muscle cells developing in vivo in the absence of motor neurons. In the present study, postsynaptic specializations such as junctional folds, postsynaptic density and basal lamina were studied in normal and aneural muscles. The superior oblique muscle of duck embryos was made aneural by permanent destruction of trochlear motor neurons by cauterizing midbrain on embryonic day 7; 3 days before the motor neurons normally project their axons into the muscle. Normal and aneural muscles from embryonic days 10 to 25 were processed for electron microscopy. The results indicate that morphological specializations such as junction‐like folds, postsynaptic‐like density, and basal lamina also develop in the absence of motor neuron contacts. Whether the differentiation of specialized synaptic basal lamina is dependent on the presence of motor neurons was examined by utilizing a monoclonal antibody against heparan sulfate proteoglycan. Immunohistochemical studies indicate that specialized synaptic basal lamina differentiates in the absence of motor neurons. Thus, the mechanism of development of postsynaptic components of neuromuscular junction in this muscle is not dependent on motor neuron contacts. These results also suggest that the postsynaptic cell plays a more active role in synapse formation than previously realized. The results are discussed in relation to the control of synapse numbers by the postsynaptic cell.
Survival and neuritic growth of sympathoadrenal (chromaffin) precursor cells in vitro
Authors: Seidl K. , Unsicker K. 
Published: April 2003

AbstractChromaffin precursor cells from embryonic rat adrenal glands were isolated at 16.3 and 20.3 days of gestation and purified by centrifugation on density gradients. Approximately 50% of the cells of both age groups that had attached to the culture substratum by 12 hr survived during a 4‐day culture period in the absence of exogenous trophic factors. Nerve growth factor (NGF) and a C6 glioma‐cell‐conditioned medium (C6‐CM) had no or a very moderate promoting effect on survival. The gluco‐corticoid dexamethasone (DEX) supported the survival of 70–80% of the cells that otherwise would have died. Spontaneous neuritic growth of the sympathoadrenal precursor cells was significantly more pronounced with cells isolated at embryonic day (E) 16.3 than at E20.3. NGF had a significantly smaller promoting effect on neurite ougrowth at E16.3 than at E20.3. C6‐CM induced neurite outgrowth from 25% (E16.3) and 35% (E20.3) of the surviving cells. DEX (10−6 M) completely abolished spontaneous neuritic growth and partially suppressed C6‐CM‐mediated fiber outgrowth. These data underscore the importance of glucocorticoids for the maintenance and development of an endocrine morphologic phenotype of sympathoadrenal precursors. They suggest that the cells may be initially driven by growth factors other than NGF into a neuronal direction and that they lack NGF‐responsiveness and dependence during the early stages of their development.
Developmental changes in 5‐hydroxytryptamine immunoreactivity of sympathetic cells
Authors: Soinila Seppo , Ahonen Marketta , Lahtinen Tuija , Häppölä Olli 
Published: April 2003

Abstract5‐Hydroxytryptamine was demonstrated immunohistochemically in developing sympathetic chain ganglia, adrenal medullae and retroperitoneal paraganglionic tissue. Initially, all catecholamine‐synthesizing cells were immunoreactive to 5‐hydroxytryptamine, but during the maturation some sympathetic cell types lose this property. In the ganglia, small intensely fluorescent cells retain their 5‐hydroxytryptamine content throughout maturation. This property is expressed transitionally in some neonatal principal neurons, but can be triggered even in adult neurons, e.g. after loading with l‐tryptophan. In the adrenal medulla, immunoreactivity to 5‐hydroxytryptamine is carried over to the adrenaline‐synthesizing cells, while in the main retroperitoneal paraganglion it is observed in both adrenaline and noradrenaline cells. These results suggest that initial expression of 5‐hydroxytryptamine immunoreactivity is coupled to the onset of catecholamine synthesis, but is regulated differently in each mature sympathetic organ.
NGF primed spleen cells injected in brain of developing rats differentiate into mast cells
Authors: Aloe Luigi , De Simone Roberta 
Published: April 2003

AbstractThe aim of this work was to study the topographic distribution and the morphological behaviour of nerve growth factor (NGF) primed spleen cells injected into the lateral ventricles of developing rat brain. Serial coronal brain sections showed that these transplanted cells acquire phenotypical characteristics similar to those of mast cells (MCs) and that they enhance local neovascularization. These results, together with the observation that these cells are located in proximity to the hippocampus, a brain tissue which contains one of the highest levels of NGF, provide a model for studying the relationship between NGF and MC differentiation and secretion.
Non‐selective afferent innervation develops in embryonic mouse spinal cord‐dorsal root ganglia explants chronically exposed to GM1 ganglioside
Authors: Baker Robert E. , Janzen Daan Gaasbeek 
Published: April 2003

AbstractProjection patterns of dorsal root ganglion afferents within organotypic expiants of fetal mouse spinal cord were examined histologically using a horseradish peroxidase staining method. All expiants were also examined electrophysiologically and showed spontaneous and evoked bioelectric discharges, which were evenly distributed across the cord explants. Explants chronically grown in a serum‐free medium containing the monosialoganglioside GM1 failed to develop dorsal cord selectivity as was previously observed when a mixture of gangliosides was used. It therefore appears that not all gangliosides can induce selectivity in this model.
Gangliosides of the mouse spinal cord: A comparison in in vivo and in vitro tissues
Authors: Baker R. E. , Guérold B. , Dreyfus H. 
Published: April 2003

AbstractGanglioside profiles in spinal cord from 13‐day mouse fetuses, 21‐day postnatal and adult mice were compared with those harvested from organotypic cross‐sections of fetal mouse spinal cord grown for 28 days in vitro in a serum‐free medium. All the major species of gangliosides reported for brain were present both in the in vivo tissue and cultured spinal cord, though not necessarily at each developmental stage examined. Fresh tissues showed increases and decreases in various gangliosides as have been reported for higher brain centers at similar stages of development in mammals and birds. However, qualitative and quantitative differences exist between fresh spinal cord and cultured cord explants as well as between galactose‐grown and galactose‐free cultures. Spinal cord explants grown in the presence of galactose showed measurable amounts of GM2 and GM3 which were not detected in the control‐defined medium‐grown cultures. The differences between the two culture groups may be related to interneuronal connectivity patterns.
In vitro experiments on neuronal and glial cell lineages among the ventricular cells of the mouse neural plate
Authors: Buse Eberhard , Kindler‐Röhrborn Andrea , Rajewsky Manfred F. 
Published: April 2003

AbstractThe proliferative ventricular cells of the early neural plate of the mouse are generally assumed to be pluripotent and equivalent to one another in their developmental capability. Ventricular cells from the rostral parts of the neural plates of mice (Theiler stages 11 and 12, embryonic days 71/2 and 8) were studied in tissue culture with respect to their potential to give rise to neurons or glial cells, or both. Auto‐radiographic and immunohistochemical analyses showed that ventricular cells developing into neuronal phenotypes stopped proliferating immediately upon transfer to cell culture. Using polyclonal anti‐GFAP antibodies, a small proportion of immunoreactive cells could be detected after 4 days of culture. These cells retained their proliferative activity, displayed morphological characteristics of radial glial cells and may have either developed from specific glial progenitor cells or have been induced to proceed along the glial differentiation pathway at the beginning of culture. Therefore, two distinct types of progenitor cells, committed either to neuronal or glial lineages, appear to co‐exist among the cultured neural plate ventricular cells.
Regional maturation of neurotransmitter‐related and glial markers during postnatal development in the rat
Authors: Virgili M. , Barnabei O. , Contestabile A. 
Published: April 2003

AbstractNeurotransmitter‐related (choline acetyltransferase, acetylcholinesterase, glutamate decarboxylase, l‐glutamate and GABA high affinity uptake) and glial neurochemical markers (glutamine synthetase, β‐alanine uptake and 2′,3′ cyclic nucleotide phosphohydrolase) have been quantitatively assayed in various regions of the rat CNS during normal postnatal development: spinal cord, cerebellum, superior colliculus, hippocampus, striatum, visual cortex, frontal sensory‐motor cortex and prefrontal cortex. In general, neurochemical markers show an obvious trend toward increasing levels in parallel with brain maturation. However, some relevant exceptions have been observed and discussed. Detailed knowledge of regional neurochemical brain maturation is important since it gives us information concerning some key events of brain development. In addition, this knowledge is the essential pre‐requisite for studies aimed at the alteration of specific regional and temporal parameters through experimental manipulation.
Synapse formation on quail trochlear neurons transplanted in duck embryos before naturally occurring motor neuron death
Authors: Sohal G. S. , Bal H. S. , Campbell L. R. , Husain I. , Arumugam T. , Kumaresan K. 
Published: April 2003

AbstractAbout half of the trochlear motor neurons in duck and quail embryos die during normal development. In a previous study the role of target muscle in controlling the number of surviving motor neurons was investigated by reducing the number of neurons innervating the muscle. This was accomplished by removing the midbrain of the duck embryo and grafting in its place the midbrain of the quail embryo before motor neuron death begins. It was observed that the number of surviving trochlear motor neurons in the quail‐duck chimera embryos was not significantly different from that of the normal quail. The present investigation was undertaken to determine whether trochlear motor neurons in the chimera embryos received afferent synapses. Brains of duck, quail and chimera embryos on days 16 and 20 were processed for electron microscopical observations. Synapses formed on motor neurons of the chimera embryos. Surprisingly, synapses on motor neurons of quail differed from those of duck, both qualitatively and quantitatively. Synapses on the motor neurons of the chimera embryos developed in a fashion similar to that for the duck motor neurons. Our failure to rescue trochlear motor neurons in the chimera embryos suggests that the developing motor neurons may respond to a larger target muscle only if they received a normal complement of afferent synaptic input.
Subcellular and regional distribution of casein kinase II and initiation factor 2 activities during rat brain development
Authors: Martín Maria Elena , Alćazar Alberto , Salinas Matilde 
Published: April 2003

AbstractThe possible relationship between the subcellular and regional distribution of the activities of initiation factor 2 and casein kinase II, responsible for the phosphorylation of the β subunit of the factor, has been studied during postnatal rat brain development. Both activities have been measured in four brain regions: diencephalon, hemispheres, cerebellum and brain stem, and in two subcellular fractions: postmicrosomal supernatant and the protein fraction associated with ribosomes, or crude initiation factors fraction.The specific activity of both the factor and the protein kinase is much higher in the protein fraction associated with ribosomes than in the soluble fraction and slightly higher in the hemispheres than in the other three regions. Changes in the activity of both proteins are in parallel with development, the activities increase in the postmicrosomal supernatant and decrease in the fraction associated with ribosomes from suckling (5‐day‐old) to adult (60‐day‐old) animals.The total activity of the factor and its kinase, calculated by summation of the activities of both sub cellular fractions, does not change during development, and the distribution of activities between the two subcellular fractions observed during brain development, appears as an attractive regulation mechanism for the function of both proteins.
Analysis of the ontogeny of galanin in the rat central nervous system by immunohistochemistry and radioimmunoassay
Authors: Sizer A. R. , Ro̊kaeus Å. , Foster G. A. 
Published: April 2003

AbstractThe development of galanin‐like immunoreactivity in the rat central nervous system has been investigated immunologically. Galanin‐positive processes in the central nervous system were first recognized at day 1 post‐natal, in the dorsal horn of the spinal cord. At day 2, the first galaninimmunoreactive neuronal somata were visualized in several regions of the diencephalon; at later stages of maturation positive cells were also detected in many brain stem areas. The number, density and staining intensity of galanin‐positive structures in these and other regions increased steadily until day 28, by which age the adult disposition was attained. Increases in the concentrations of galanin‐like immunoreactivity during maturation of the animals closely paralleled the immunohistochemical findings. No reduction in galanin‐like immunoreactivity was noted in any area during later post‐natal ages.The present study indicates that the ontogeny of galanin‐like immunoreactivity in the rat central nervous system occurs entirely post‐natally. The developmental profile is consistent with the rôle of galanin as a putative neurotransmitter/neuromodulator in the rat brain and spinal cord.