bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on noradrenergic alterations in relation to early phenobarbital‐induced behavioral changes
Authors: Yanai Joseph , Pick Chaim G. 
Published: April 2003

AbstractMice were exposed to phenobarbital prenatally (B offspring) by feeding their mother 3 g/kg phenobarbital in milled food on gestation days 9–18; control dams received unadulterated milled food. At age 50 days, B offspring had fewer fluorescing noradrenergic (NE) cells in the locus coeruleus than control (P < 0.001). Hippocampal NE levels were also lower in B than in control offspring, while the cerebellar NE levels of B offspring remained normal. Since B offspring are known to be deficient in their hippocampal eight‐arm maze behavior, an attempt was made to reverse the behavioral deficit by transplantation of normal embryonic locus coeruleus NE cells into the impaired hippocampus of B offspring. While sham and NE‐transplanted controls needed approximately 2 days to reach criterion in the maze, sham‐transplanted B required approximately 5 days to reach criterion (P < 0.01). The scores of NE‐transplanted B mice were similar to B and differed significantly from control (P < 0.01). Thus, it appears that the hippocampal behavioral deficits studied may not be related to alterations in locus coeruleus‐hippocampal NE innervations.
Acetylcholinesterase in neuroblastoma and neuroblastoma × glioma hybrid cells: Cellular localization and molecular forms
Authors: Melone M. A. R. , Longo A. , Taddei C. , Augusti‐Tocco G. 
Published: April 2003

AbstractThe cellular localization of acetylcholinesterase (ACHE) was investigated at the electron microscope (E.M.) in a neuroblastoma and neuroblastoma × glioma hybrid line, which differ for their ability to establish synaptic contacts. Only cells of the latter line show association of AChE to the plasmamembrane, while in the former the activity is mainly intracellular. Sucrose sedimentation analysis of AChE molecular forms has shown no significant differences in the distribution of the two forms, G2 and G4, between the two cell lines. On the contrary a marked difference is observed in the ability of the cell to release the enzyme in the culture medium. In fact the cells lacking AChE on their surface release in the medium a much higher proportion of their enzyme, than the cells showing AChE association to their plasmamembrane. The possible role of two alternative fates for AChE, secretion or membrane insertion, in determining the observed differences of enzyme localization is discussed.
A developmental influence of substance P on its receptors
Authors: Handelmann Gail E. , Shults Cliff W. , O'Donohue Thomas L. 
Published: April 2003

AbstractEvents which alter the chemical environment of the developing nervous system have longterm consequences for neural function and behavior. Neonatal exposure to a peptide neurotransmitter, substance P (SP), increased the number of SP binding sites in the adult rat salivary glands, without altering their affinity. The neonatal treatment also increased the binding capacity for SP of several brain regions, but had no effect on SP levels in the brain. The increase in SP binding sites may be responsible for increases in sensitivity to SP in adults after neonatal treatment with the peptide.
Age‐dependent β‐adrenergic response of neuronal discharge in the raphe dorsalis: Evidence of a transient regulation
Authors: Lanfumey Laurence , Adrien Joëlle 
Published: April 2003

AbstractExtracellular recordings from raphe dorsalis neurons in rats during development were performed, and the response to iontophoretically applied β‐antagonists was analysed. In pups younger than 2 weeks, raphe dorsalis firing was totally or partially inhibited by application of β‐antagonists, while after 2 weeks of age the neurons were insensitive to the same application. The β‐receptors appeared to be involved in the control of raphe firing during a transient period of ontogenesis and thus the disappearance of β‐regulation at older ages may reflect the regression of this population of neurotransmitter receptors.
Latex beads phagocytosis capacity and ecto‐NAD+ glycohydrolase activity of rat brain microglia cells in vitro
Authors: Bocchini V. , Rebel G. , Massarelli R. , Schuber F. , Muller C. D. 
Published: April 2003

AbstractConditions are described which allow the preparation in vitro of pure (> 95%) microglial cell cultures isolated from newborn rat brain. Such ameboid cells cultivated in vitro can efficiently phagocytize opsonized latex beads and are capable of ingesting more (100–200 beads of 1.1 μm diameter per cell) and larger (6.4 μm) particles than other nerve cells, such as oligodendrocytes and astroglia. The microglial cells also show an important ecto‐NAD+ glycohydrolase activity which is characteristic of phagocytic cells. We noted that the phagocytic capacity and ecto‐NAD+ glycohydrolase of these cells were correlated and increased notably during the in vitro culture.Microglia cultivated in vitro appear to be a good model to study the activation of phagocytic properties in the central nervous system and corresponding modulation by natural or pharmacological immunomodulators.
Effects of calcium ion on neurite outgrowth of rat spinal cord neurons in vitro: The role of non‐neuronal cells in regulating neurite sprouting
Authors: Hantaz‐Ambroise D. , Trautmann A. 
Published: April 2003

AbstractThe interactions of nerve cells with their environment and other cells are specific to different stages of cellular differentiation. Neurite outgrowth was measured from cultured spinal cord neurons under the influence of different Ca2+ concentrations. We used fluorodeoxyuridine (FuDr), an antimitotic agent which reduces significantly the proportion of non‐neuronal cells in spinal cord cell cultures, to examine the effects of non‐neuronal cells on neurite outgrowth. Spinal cord neurons responded to changes in their environment by means of two types of neurite outgrowth: sprouting and elongation. The concurrent presence of non‐neuronal cells led to increased sprouting of neurites in certain ionic environments, thus lending support to the idea that non‐neuronal cells release diffusible factors which influence sprouting and guide neurite outgrowth.
Malic enzyme activity in the developing rat brain in relation to thyroid status
Authors: Thakare U. R. , Shah D. H. , Vijayan U. 
Published: April 2003

AbstractMalic enzyme activity in the soluble fraction of neonate brains from mothers fed with propylthiouracil (0.015% w/v) in drinking water from day 12 of the gestation period was significantly lowered (P < 0.01) as compared to the offspring of normal mothers. Supplementation of triiodothyronine to the neonates from experimental mothers restored the malic enzyme activity to normal levels. However, administration of triiodothyronine to adult control rats did not influence malic enzyme activity in the brains of these animals. Our data suggest that during the initial critical period of brain maturation, malic enzyme is under the control of thyroid hormones. The response of malic enzyme towards thyroid hormones is lost once the brain has matured.
Soluble neural cell adhesion molecule in brain, cerebrospinal fluid and plasma in the developing rat
Authors: Dalseg Anne‐Marie , Linnemann Dorte , Bock Elisabeth 
Published: April 2003

AbstractNeural cell adhesion molecule (NCAM) is a glycoprotein found in neurons, glial cells and muscle cells. In this report we describe the polypeptide composition and amount of soluble NCAM in brain, cerebrospinal fluid (CSF) and plasma in rats of various ages. One‐two percent of total NCAM in rat brain was shown to be buffer‐soluble. Soluble NCAM in brain, extracted at pH 7.2, constituted an increasing relative proportion of total NCAM during development, whereas the concentration of soluble NCAM in both CSF and plasma decreased in the same period. By radioiodination of brain extracts, CSF, and plasma, soluble NCAM was found to be composed of up to five polypeptides with molecular weights (Mr) of 200,000, 170,000, 150,000, 115,000 and 80,000. The relative composition did not vary significantly with age. The major forms in brain were the polypeptides with Mr of 200,000 and 115,000, whereas in CSF all forms seemed to appear in equal amounts. In plasma the 200,000 and the 170,000 Mr polypeptides were not observed and here the major forms were the 150,000 and 115,000 Mr polypeptides.
Patterns of transiently expressed acetylcholinesterase activity in cerebral cortex and dorsal thalamus of developing rats with cytotoxin‐induced microencephaly
Authors: Robertson Richard T. , Gragnola Thomas G. , Yu Jen 
Published: April 2003

AbstractPrevious studies have demonstrated that acetylcholinesterase (AChE) activity is expressed transiently by thalamocortical neurons of primary sensory systems in developing rat pups. In the present study, prenatal treatment with methylazoxymethanol acetate (MAM) on embryonic day 15, 16, or 17 resulted in rat pups with cerebral cortices markedly reduced in thickness and areal extent. Histochemical studies demonstrated that AChE staining occurs in fiber‐like plexuses in primary visual, auditory, and somatosensory regions of developing cerebral cortex of MAM‐treated animals, just as in normal developing rats, but that the transient patterns of AChE are found more superficially than normal and they occur in an abnormal patchy distribution. Neuronal somata in thalamic lateral geniculate, medial geniculate and ventral basal nuclei of MAM‐treated animals show transient AChE staining indistinguishable from that seen in normal animals. These data indicate: (1) AChE is expressed transiently by thalamocortical neurons in MAM‐treated animals, (2) intensity of the transiently expressed AChE is not affected by MAM‐induced loss of cortical neurons, and (3) the abnormal AChE patterns in cortex likely reflect the abnormal distributions of thalamocortical terminal fields that are characteristic of MAM‐treated animals.
Effect of thyroid deficiency on actin mRNA content in the developing rat cerebellum
Authors: Faivre‐Sarrailh C. , Ferraz C. , Liautard J. P. , Rabié A. 
Published: April 2003

AbstractThe actin mRNA content of the cerebellum was determined in normal and hypothyroid developing rats using RNA dot hybridization with a β‐actin cDNA probe. The decline in actin mRNA content occurring during the second postnatal week in normal development was delayed by about 1 week in hypothyroid rats. Since this effect coincides exactly with the delay in actin filament formation recently reported in thyroid‐deficient rats, it strengthens the hypothesis of an inverse relationship in the developing brain between the polymerization state of actin and the production of actin mRNA.
Age‐related changes in uptake and release on l‐[3H]noradrenaline in brain slices of senescence accelerated mouse
Authors: Zhao Xue‐Hui , Nomura Yasuyuki 
Published: April 2003

AbstractHigh K+ and N‐methyl‐d‐aspartate (NMDA) evoked l‐[3H]noradrenaline (NA) release to a similar degree in the brain slices of 1‐month‐old senescence‐accelerated resistant mice (SAM‐R/1) and senescence‐accelerated prone mice (SAM‐P/8). However, 30 mM KCl‐induced l‐[3H]NA release significantly diminished in SAM‐P/8 from 3 to 12 months without changing in SAM‐R/1. In addition, NMDA‐induced l‐[3H]NA release was also reduced at 3 months and lowered to a level of spontaneous release at 12 months in SAM‐P/8, but no age‐related changes in SAM‐R/1 were observed. It is suggested that NA release from NA nerve terminals responsive to depolarization is reduced in SAM‐P/8 at an earlier stage than in SAM‐R/1. Furthermore, NMDA receptors which could be localized in the soma and/or nerve terminals, seem to be involved in NA release and to be decreased with advancing age in SAM‐P/8.
Choroidal ependymocytes in culture: Expression of markers of polarity and function
Authors: Péraldi‐Roux S. , Dao B. Nguyen‐Than , Hirn M. , Gabrion J. 
Published: April 2003

AbstractLong‐term primary cultures derived from fetal mouse or rat choroid plexus were obtained in serum‐supplemented media. Monoclonal and polyclonal antibodies to basolateral and apical membrane components were used to observe the expression of specific markers of polarity and function. Choroid plexus cultures and thin frozen sections of adult tissues were compared by immunocytochemistry. Two polyclonal antibodies directed against laminin and fibronectin were used on cultured choroid plexus and sectioned tissues, showing that fibronectin and laminin are located on the basolateral membrane domain in ependymocytes in vitro, as well as in vivo. Na+‐K+ATPase was apically detected by light and electron microscopy with a monoclonal antibody (Mab H30) in both cultured cells and sectioned tissues. Double immunofluorescent staining with Mab H30 and affinity‐purified polyclonal antibodies to the α subunit of G0 protein (G0α) demonstrated the relatively similar distribution of the two antigens on the apical face of the choroidal tissue, both in vivo and in vitro. The distribution of these markers shows a typical differentiation with maintenance of polarized features in choroidal ependymocytes in culture, testifying that this cell culture system constitutes an interesting model for studying the functional characteristics of ependymal cells of the choroid plexus.
DNA synthesis experimentally induced in neurons: Tetraploidy or hyperdiploidy?
Authors: Poncino A. , Geuna S. , Scherini E. , Robecchi M. G. Giacobini , Filogamo G. 
Published: April 2003

AbstractDNA synthesis triggered in Auerbach's plexus neurons by hypertrophy of muscular territory is related to a condition of hyperdiploidy.
Expression and quantitative changes of carbonic anhydrase in developing neurones of rat central nervous system
Authors: Nógrádi Antal , Mihály András 
Published: April 2003

AbstractPostnatal changes in carbonic anhydrase activity were investigated in the islands of Calleja, which have been previously reported to contain the enzyme. Results obtained with a new modified method of Hansson provided further evidence for the distinction between the medial and lateral islands of Calleja. The enzyme was localized mainly in the nucleus and cytoplasm of granule cells without showing binding to any cytoplasmic organelle. No large neurons of the islands displayed carbonic anhydrase reactivity. The time course and rate of increase of carbonic anhydrase expression were different in the giant island of Calleja and lateral islands and this finding may strengthen the hypothesis regarding the medio‐lateral diversity of Calleja's islands. On the other hand, at the end of the maturation process the granule cell complexes showed no significant difference in the proportion of carbonic anhydrase positive neurones. The almost equal rate of appearance of carbonic anhydrase reactive granule cells raises the possibility of a basic common role of both medial and lateral islets.
Absolute refractory period of human nerve fibres during postnatal myelination
Authors: Duron Bernard , Khater‐Boidin Josette 
Published: April 2003

AbstractIn order to study the absolute refractory period of a given group of nerve fibres during development we measured absolute refractory periods and conduction velocities of motor fibres and the most excitable fibres in the human ulnar nerve of newborns, children and adults. In each group of nerve fibres absolute refractory period was not correlated to conduction velocity (i.e. fibre diameters) and was rather constant during development. However, absolute refractory period of the most excitable fibres was smaller than absolute refractory period of motor fibres independently of the subject's age. Thus, it appears that already at birth, absolute refractory period is characteristic for a given group of nerve fibres.
Effects of serotonin on intracellular calcium in embryonic and adult Helisoma neurons
Authors: Goldberg Jeffrey I. , Mills Linda R. , Kater Stanley B. 
Published: April 2003

AbstractThe neurotransmitter serotonin has been shown to regulate neurite outgrowth in many embryonic and adult Helisoma neurons. To determine whether intracellular calcium concentration is also regulated by serotonin in large numbers of neurons, the calcium indicator Fura 2 was used to measure intracellular calcium in mass‐dissociated cultures of embryonic and adult neurons. Comparisons between embryonic and adult neurons revealed that embryonic neurons have a narrow population distribution of rest intracellular calcium levels around relatively low values. In contrast, the population distribution for adult neurons covered a much wider range of rest calcium concentrations. In both embryonic and adult cultures, serotonin induced a shift in the population distribution of calcium concentrations to higher levels, and increased the mean and median calcium concentrations. Analysis of individual adult neurons prior to and following the addition of serotonin revealed that approximately 50% of the neurons responded with an increase in calcium concentration. In contrast, there was no evidence of a serotonin‐induced decrease in calcium concentration in any neurons. Since the percentage of neurons responding to serotonin in this study is very similar to the percentage that responded in previous studies on neurite outgrowth, these data support the hypothesis that an increase in intracellular calcium is a common intermediate step in the regulation of neurite outgrowth by serotonin throughout the Helisoma nervous system.
Activation of phosphoinositide turnover and protein kinase C by neurotransmitters that modulate calcium channels in embryonic chick sensory neurons
Authors: Harish O.E. , Role L.W. 
Published: April 2003

AbstractGamma aminobutyric acid (GABA) and norepinephrine modulate the excitability of primary chick sensory neurons by decreasing the voltage dependent Ca current. Although previous electro‐physiological studies indicate that neurotransmitter modulation of the Ca current in these neurons involves protein kinase C, the biochemical aspects of this mechanism have not been examined directly. We find that both norepinephrine (via a unique a receptor subtype) and GABA (via GABAb receptors) linked to pertussis toxin sensitive pathways, stimulate the metabolism of membrane phosphatidylinositol phospholipids in primary chick sensory neurons. In addition, norepinephrine causes the rapid translocation of C kinase activity from cytosolic to membrane associated distribution, consistent with its rapid activation in response to applied neurotransmitter. The pharmacology, pertussis toxin sensitivity and time course of the biochemical changes due to neurotransmitter treatment parallel the effects of these transmitters on calcium current modulation. These biochemical studies confirm the hypothesis that activation of protein kinase C is critically involved in calcium channel modulation in embryonic chick sensory neurons.
Correlation between p19 presence and MHC class II expression in human fetal astroglial cells cocultured with HTLV‐I donor cells
Authors: Macchi B. , Caronti B. , Cocchia D. , Gremo F. , Torelli S. , Sogos V. , Bonmassar E. , Lauro G.M. 
Published: April 2003

AbstractThe possibility of a direct infection of human brain by HTLV‐I, has been studied using an in vitro model. Human fetal astroglial cells were cocultivated with irradiated HTLV‐I donor cell line MT‐2, and assayed for the presence of HTLV‐I core protein p19 after 1 week. Fifty‐six per cent of GFAP positive astrocytes showed the viral core protein p19 and increased expression of Class II MHC antigens. Electron microscopy of astroglial cells exposed to HTLV‐I revealed the presence of vacuoli‐like structures containing viral core protein p19. Cell intermediate filament cytoskeleton was also disorganized. Even if this study does not provide direct evidence for virus replication inside astroglial cells, all these findings suggest that HTLV‐I can indeed enter the cell and exert a cytopathic effect. Therefore the results of the present study are consistent with the hypothesis that astroglial cells could be involved in demyelination processes occurring in the HTLV‐I associated neurological disorders, such as human associated myelopathy and tropical spastic paraparesis.
Localization and activity of transglutaminase, a retinoid‐inducible protein, in developing rat spinal cord
Authors: Perry Michael J.M. , Haynes Laurence W. 
Published: April 2003

AbstractThe distribution of the retinoid‐inducible enzyme, tissue transglutaminase (tTG) in developing rat spinal cord was determined by enzyme assay and immunocytochemistry. tTG activity was at its highest in the forebrain in late foetal development. In hindbrain and spinal cord, elevated activity persisted until after birth. In spinal cord only, a second peak of activity occurred during the first week post partum (P3). tTG was associated with both the cytosolic and particulate tissue fractions throughout spinal cord development, but the particulate component was more prominent in the early postnatal period. tTG was more concentrated during this period in the ventral horn, where the particulate‐associated enzyme activity was highest. In spinal cord at 3 days post partum, particulate tTG could be solubilized with lubrol‐PX, dithiothreitol and potassium thiocyanate. Both soluble and particulate‐associated tTG coeluted with guinea‐pig liver transglutaminase C by DEAE‐sephacel chromatography. The first peak of tTG activity during late foetal life coincided with the transient localization of the enzyme by immunocytochemistry in vascular endothelia throughout the spinal cord. The second peak of activity at 3 days post partum, by which time vascular immunoreactivity was absent, coincided with the occurrence of small numbers of intensely immunoreactive motor neurones in the ventral horn. Immunoreactive motor neurones were seen predominantly at two levels: the lower thoracic segments and lumbar enlargement. The abnormal appearance of many immunoreactive neurones suggested degenerative changes were occurring. tTG was also present in central canal cluster cells from birth onwards. No neuronal immunoreactivity was seen throughout foetal development. A proportion of motor neurones prepared from E15 spinal cord and grown in coculture with spinal cord astrocytes, were immunoreactive for tTG. All immunoreactive neurones showed signs of degeneration. Addition of myotube‐conditioned medium (a source of cholinergic differentiation factor, CDF) reduced the proportion of tTG‐immunoreactive neurons in the cultures. Schwann cell‐conditioned medium (a source of ciliary neurotrophic factor, CNTF) had a similar but less potent effect on the numbers of immunoreactive neurones. The possibility that tTG is a marker for late, but not early‐phase programmed cell death in the developing rat spinal cord is discussed in the light of a proposed role for tTG in the mechanism of natural cell death by apoptosis.
Developmental profile of glucocorticoid binding to synaptic plasma membrane from rat brain
Authors: Sze Paul Y. , Towle Andrew C. 
Published: April 2003

AbstractThe plasma membranes of several mammalian tissues including the brain are known to have specific binding sites for glucocorticoids. The developmental changes in specific glucocorticoid binding to synaptic plasma membrane (SPM) from rat brain were determined at various postnatal ages, using [3H]triamcinolone acetonide (TA) as the steroid ligand. The specific binding of the labeled glucocorticoid to SPM during the first 2 postnatal weeks was only 40% of the adult level. An increase of the specific binding occurred after day 15 and this developmental rise of binding reached the adult level approximately by the end of the fourth week. Methodologically, these developmental data are detailed in the present article to include nonspecific binding as well as specific binding. Scatchard analysis indicates that the developmental rise of the specific glucocorticoid binding was due to an increase in the membrane binding sites. The ontogenetic increase of membrane binding sites during postnatal brain development provides additional evidence that these binding sites have physiological significance in brain function.