bluuebunny/crossref_metadata_2025_split huggingface dataset:
Developing rat cerebellum: Glutamine and glutamate influx correlated to the cellular distribution of glutamine synthetase
Authors: de Barry J. , Ghandour M. S. , Gombos G. 
Published: April 2003

AbstractGlutamate has been suggested to be the neurotransmitter of the granule cells in cerebellar cortex. Autoradiographic studies using very low concentrations (1μM range) of 2‐3‐[3H]l‐glutamate or 2‐3‐[3H]l‐glutamine have shown that both amino acids were preferentially taken up in the molecular layer of the cerebellar cortex of adult rats, but [3H]Glu accumulated essentially in glial cells, while Gln did not show a cellular preference (de Barry et al., Neuroscience 7,1289–1297,1982).In this paper we show that during development the preferential accumulation of [3H]Glu and [3H]Gln are the same as in the adult but, in addition, at young ages (7–10 days) [3H]Gln accumulated in replicating cells of the external granular layer (EGL). The absence of glutamine synthetase in the EGL cells suggests that this accumulation of exogenous Gln might be used for the synthesis of purines and pyrimidines required for the active multiplication of these cells and is not correlated to neurotransmission. The metabolism of [3H]Gln was slow at young ages and changed during development. The metabolism of the Glu taken up was constant throughout development which is consistent with the hypothesis that high affinity Glu uptake is mainly a glial cell property and that the increasing accumulation rate during development reflects glial maturation.
Intraocular transplants of olfactory neuroepithelium in rat
Authors: Heckroth John A. , Graziadei G. A. Monti , Graziadei Pasquale P. C. 
Published: April 2003

AbstractOlfactory neuroepithelium of neonatal rat pups has been transplanted in the anterior chamber of the eye of adult rats. Structural and ultrastructural observations at 5, 10, 30, 50, 90 and 120 days show that mature neurons degenerate rapidly in the expiant (before 5 days) while the basal elements proliferate and produce a new population of young neurons between 1 and 10 days. At longer survivals (30–120 days) it is seen that the neurons acquire morphological maturity, and positivity to the olfactory marker protein, as demonstrated by immunohistochemical methods. Our observations show that new neurons can be generated in the transplanted neuroepithelium and that their generation and maturation occurs in the absence of connections with a brain target.
Effects of extended periods of reserpine and α‐methyl‐p‐tyrosine treatment on the development of the putamen in fetal rabbits
Authors: Tennyson Virginia M. , Gershon Perry , Budininkas‐Schoenebeck Mary , Rothman Taube P. 
Published: April 2003

AbstractDeveloping nigrostriatal neuroblasts exhibit catecholamine‐induced fluorescence before their axons have left the vicinity of the cell bodies. To evaluate possible developmental effects of dopamine, we have used reserpine and α‐methyl‐p‐tyrosine to deplete dopamine chronically during the development of these axons. We found that dopamine‐induced fluorescence was either absent or markedly decreased in the fetal putamens. To determine whether the absence of fluorescence was due to a reduction of dopamine terminals, the uptake of tritium‐labeled dopamine was measured in the putamen. Uptake of labeled dopamine was significantly depressed in reserpine‐treated fetuses to 70% of that of controls; however, no depression of labeled dopamine was found in the α‐methyl‐p‐tyrosine‐treated fetuses. After both drug treatments, the striatal perikarya were less mature than those of controls. Although we cannot rule out possible non‐specific or toxic effects of the drugs, these observations support the conclusion that presynaptic dopamine may be important for development of target neurons in the neostriatum.
Neurogenesis in the rat neostriatum
Authors: Bayer Shirley A. 
Published: April 2003

AbstractNeurogenesis in the rat neostriatum was examined with [3H]thymidine autoradiography. For the animals in the prenatal groups, the initial [3H]thymidine exposures were separated by 24 h; they were the offspring of pregnant females given two injections on consecutive embryonic (E) days (E13–E14, E14–E15, … E21–E22). For the animals in the postnatal (P) groups, the initial [3H]thymidine exposures were separated by 48 h, each group receiving four consecutive injections (P0–P3, P2–P5, P4–P7). On P60, the percentage of labeled cells and the proportion of cells originating during either 24 or 48 h periods were quantified at several anatomical levels for both the large and medium‐sized neurons. Neurogenesis of the large neurons occurs mainly between E13 and E16 in a strong caudal‐to‐rostral gradient. The medium‐sized neurons throughout the neostriatum are generated in a prominent ventrolateral‐to‐dorsomedial gradient so that ventrolateral cells originate mainly between E14 and E18, dorsomedial cells between E18 and E21–22 (fewer than 10% originate between P0 and P4). Medium‐sized neurons also show two other gradients. First, there is a superficial‐to‐deep gradient in the anterior part of the caudoputamen, while more posterior levels have a deep‐to‐superficial gradient. Second, anterior parts have a caudal‐to‐rostral gradient while posterior parts have a gradient in the opposite direction. This shift in neurogenetic gradients along both superficial‐deep and rostrocaudal directions is developmental evidence that an anterior ‘caudate’ can be separated from a posterior ‘putamen’ in the rat. Finally, neurogenetic gradients in the medium‐sized caudoputamen neurons can be linked to the patterns of their anatomical interconnections with the substantia nigra.
The influence of neurite‐inducing agents on cholinergic activity in human neuroblastoma cells
Authors: Sternberg Hal , Cole Gregory , Timiras Paola S. 
Published: April 2003

AbstractVarious factors capable of inducing morphological differentiation of neuroblastoma cells were studied to determine whether they may also specifically regulate cholinergic function in human cholinergic neuroblastoma cells MC‐IXC. Choline acetyltransferase (CAT) activity was monitored to reflect cholinergic function while Mg2+ ATPase activity was monitored to reflect effects which are not related specifically to neuronal function. Among the agents, dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), D‐α‐tocopherol, ascorbic acid and dibutyryl‐cAMP, only low doses of DMSO were found to selectively inhibit CAT activity while Mg2+ ATPase activity along with population growth remained unaffected. Of the three chemically related organic compounds tested (DMSO, DMF, DMA), DMSO was the least potent with regard to inhibition of population growth and Mg2+ ATPase activity while DMA was the most potent inhibitor. Sodium butyrate caused a decline in CAT activity while retinoic acid induced an enhancement. The combination of sodium butyrate with retinoic acid caused an enhancement of CAT activity similar in magnitude to that observed with retinoic acid alone. Lastly, CAT activity was found to be independent of population density unlike that in different neuroblastoma cell lines.8,12,19
Comparison of taurine, hypotaurine and β‐alanine uptake in brain synaptosomal preparations from developing and adult mouse
Authors: Kontro Pirjo 
Published: April 2003

AbstractThe properties of taurine, hypotaurine and β‐alanine uptakes were compared in brain synaptosomal preparations from 6‐day‐old and adult mice. The uptakes of these structurally related amino acids resembled each other, being concentrative, sodium‐dependent and inhibited by the same analogues. The absolute sodium requirement of uptake was already evident in developing brain. The affinity of the lowaffinity uptake for taurine was higher in immature than in adult brain. Both affinity and maximal velocity increased in hypotaurine uptake during development, whereas in β‐alanine uptake only the maximal velocity did so. The efficient synaptosomal taurine and hypotaurine transport systems in immature brain could contribute to the high taurine level in developing brain.
Hypomyelination and recovery of the myelin deficit in heterozygous jimpy mice
Authors: Rosenfeld Jeffrey , Friedrich Victor L. 
Published: April 2003

AbstractThe myelin content of the anterior commissure in female carriers of the jimpy gene (X+Xjp) and in normal male mice (X+Y) was determined using morphometric methods. Young jimpy heterozygotes (X+Xjp), 42–43 days old, exhibit a 33% reduction in myelin area fraction in the anterior limb of the anterior commissure. At older ages (⩾ 145 days), the myelin area fraction in the heterozygotes is not different from control values in the anterior limb and the posterior limb of the anterior commissure. In comparing the young and old jimpy heterozygotes, a significant increase occurs in the myelin area fraction after 43 days of age.The increase in the myelin area fraction in the anterior limb of the heterozygote may occur in response to the myelin deficit caused by the jimpy mutation and may involve the formation of new myelin. A further study of cellular interactions in the central nervous system of the jimpy heterozygote may provide new insight into mechanisms of myelin formation and remyelination.
Regulation of the amino acid availability in the developing brain. No physiological significance of amino acid competition in experimental hyperphenylalaninemia
Authors: Huether Gerald , Schott Klaus , Sprotte Uwe , Thoemke Frank , Neuhoff Volker 
Published: April 2003

AbstractChronic experimental hyperphenylalaninemia in suckling rats causes a depletion of amino acids in the blood and in the brain, and an accumulation of amino acids in the peripheral tissues. The amino acid depletion in the blood is greater than that in the brain. The amino acid accumulating potency of all body tissues is increased by the excess of phenylalanine, most pronounced in the gut, least pronounced in the brain. All body tissues compete for the amino acids circulating in the blood. This competition is enhanced in hyperphenylalaninemia. The brain is at a disadvantage in the competition of the various body tissues for the amino acids available from the common pool. Brain tissue is increasingly depleted of amino acids as the accumulation of amino acids in the peripheral tissues is stimulated in hyperphenylalaninemia.The depletion of amino acids in the blood and the simultaneous rise of the free amino acid concentrations in the various developing tissues indicates tissue‐specific shifts in the balance between protein synthesis and protein degradation in hyperphenylalaninemia.There is no indication that amino acid competition at the blood‐brain barrier contributes importantly to the depletion of amino acids in the brain tissue in hyperphenylalaninemic rats. Instead, brain amino acid pools under in vivo steady‐state conditions appear to be primarily regulated by the rate of amino acid utilization by the peripheral tissues.
Changes in ganglioside profile in chick embryo retina: Studies on tissue and cell cultures
Authors: Landa C. A. , Moscona A. A. 
Published: April 2003

AbstractThe developmental profile of gangliosides in the neural retina of the chick embryo is characterized by a progressive decrease in the concentration of GD3 complex from a high level on day 6; by a continuous increase in GD1a concentration; and by less striking increases in GD1b and GT1b concentrations during the growth phase; GM1 increases in the post‐mitotic retina. Gangliosides were analyzed by thin layer chromatography and by densitometry of the TLC plates. (Ganglioside nomenclature is according to Svennerholm.37)We have examined comparatively ganglioside changes in organ cultures of retina tissue from 6 day embryos (R36), in cell aggregates and in primary monolayer cultures of R26 cells, all maintained for 6 days in vitro. In all cases, the pattern of ganglioside changes was qualitatively similar to that in the retina in vivo. These results suggest that, unlike some other aspects of retina differentiation, the progression of ganglioside changes in the 6–12 day embryonic retina is not critically dependent on histotypic cell organization or on specific contact‐dependent cell interactions; these changes appear to be largely preprogrammed in the cells at some earlier phase of development.
Extracellular matrix glycoprotein (hyaluronectin) in early cerebral development
Authors: Bignami Amico , Delpech Bertrand 
Published: April 2003

AbstractThe distribution of hyaluronectin, an extracellular matrix glycoprotein binding specifically to hyaluronate, was studied by indirect immunofluorescence in the cerebral cortex of the rat embryo. On days 11 and 12 thin strands of immunofluorescent material spanning the entire thickness of the telencephalon were seen. The appearance was similar to that observed with vimentin antisera decorating radial glia. On days 13–15 the primordial plexiform layer of the cerebral cortex was intensely hyaluronectin positive. On day 16 hyaluronectin immunoreactivity was mainly confined to Layer I above and to the intermediate layer below the newly formed cortical plate. It is suggested that in embryonal rat brain HN immunoreactivity is first distributed along radial glia and then accumulates in regions of axonal growth and neuropil formation.
Histogenesis of the vestibular sensory epithelium in organotypic culture of mouse embryo otocysts: A tritiated thymidine autoradiographic study
Authors: Desmadryl Gilles , Raymond Jacqueline , Sans Alain 
Published: April 2003

AbstractThe cytogenesis in the vestibular sensory epithelium of mouse embryo otocysts grown in organ culture was examined using tritiated thymidine autoradiography. Pulse‐labeling with [3H]‐thymidine was applied either in vivo, at various intervals before explantation, or in vitro at specific stages of development. Observations of the development in vitro showed that the cytogenesis and cytodifferentiation of vestibular sensory cells were disturbed by explantation. By varying the intervals between the [3H]thymidine exposure and the date of explantation, we were able to demonstrate that explantation itself caused a significant decrease in the mitotic and the postmitotic phases of the hair cell precursors. Labeling of the expiants excised on day 13 of gestation revealed that precursors of the hair cells were progressively losing their mitotic capacity in vitro. In contrast with this finding, precursors of the supporting cells were less affected by explantation and culture conditions and they retained the capacity for survival, proliferation and differentiation.
The postnatal development of glial fibrillary acidic protein and neurofilament triplet proteins in rat brain stem
Authors: Harry G. Jean , Goodrum Jeffry F. , Morell Pierre 
Published: April 2003

AbstractCytoskeletal preparations containing both the glial fibrillary acidic protein and the neurofilament triplet proteins were prepared from brain stems of rats at different ages and the individual peptides separated in polyacrylamide gels. Stained peptide bands were quantitated as the area under peaks generated by densitometric scanning. Peak areas were converted to grams of protein based on total gel dye binding and total protein applied to the gels. Between 5 and 30 days, the concentration of the peptide (g of peptide/mg of tissue protein) of apparent molecular weight 51,000 (corresponding to the glial fibrillary acidic protein), increased 3 fold. The corresponding increase in total concentration of the three peptides corresponding to the neurofilament proteins was 4.5 fold. However, the increase in concentration of the individual neurofilament peptides was each different. Very little of the apparent molecular weight 210,000 neurofilament peptide was present at 5 days and its concentration increased 11 fold by 30 days compared to about 3.5 fold for the other two neurofilament peptides. These results are in general agreement with studies using immunological techniques and the methods have the advantages of using readily available techniques and allowing the simultaneous comparison of both neuronal and glial specific filaments during development.
Transient expression of neurofilament protein without filament formation in purkinje cell development
Authors: Bignami Amico , Grossi Milena , Dahl Doris 
Published: April 2003

AbstractPurkinje cell bodies and dendrites in the chick embryo stained intensely by immunofluorescence and by the Avidin‐Biotin Complex (ABC) method using monoclonal and polyclonal antibodies to the neurofilament (NF) proteins. On day 20 (the day before hatching) NF immunoreactivity markedly decreased concomitant with the first appearance of NF‐positive basket axons in the molecular and Purkinje cell layers. On postnatal day 3, as in mature avian cerebellum, NF‐negative Purkinje cells were surrounded by NF‐positive baskets. Cytoplasmic 10 nm filaments were not observed in immature and mature Purkinje cells by electron microscopy. Basket axons in the hen were packed with 10 nm filaments.
Development of specificity and stereoselectivity of rat brain dopamine receptors
Authors: Miller Jeannette C. , Friedhoff Arnold J. 
Published: April 2003

AbstractPrenatal exposure to the neuroleptic haloperidol has been reported to produce an enduring decrement in the number of dopamine D2 receptors in rat striatum and a persistent diminution of a dopamine dependent behavior, stereotypy.17 The ontogeny of rat brain dopamine binding sites has been studied in terms of the kinetic properties and phenotypic specificity in rat fetal brain through early postnatal development. Sites showing some properties of the D2 binding site can be found prior to gestational day (GD) 18, can be labeled with [3H]dopamine or [3H]spiroperidol and can he displaced with dopaminergic agonists and antagonists.5 Saturation kinetics for specific [3H]spiroperidol has previously been found to occur on or about GD 18.1.5 It is of interest that the critical period for the prenatal effect of haloperidol to reduce striatal D2 binding sites. CD's 15–18.18 coincides with the period during which dopamine binding sites lack true specificity, but can be labeled with dopaminergic ligands.In these experiments the development of stereoselectivity of brain dopamine binding sites has been examined. When rat mothers were given either the neuroleptic (+)‐butaclamol or its therapeutically inactive isomer (−)‐butaclamol during the critical period CD's 15–18. the number of [3H]spiroperidol binding sites in striata of offspring was significantly reduced by both stereoisomers. This is in marked contrast to the postnatal treatment effect by a neuroleptic in which upregulation of striatal D2 binding sites occurs only by treatment with the therapeutically active isomer (+)‐butaclamol. In vitro studies of the direct effect of the stereoisomers of butaclamol indicate that the recognition sites detected during fetal brain development with [3H]spiroperidol do not distinguish between the isomers of butaclamol. The point at which stereoselectivity is apparent also appears to be the point at which the prenatal neuroleptic effect is no longer operative and the mature response to increase the number of dopamine binding sites occurs.
Regulation of sympathetic trophic factors in smooth muscle
Authors: Rush R.A. , Abrahamson I.K. , Belford D.A. , Murdoch S.Y. , Wilson P.A. 
Published: April 2003

AbstractThe level and nature of trophic activity present in the chicken expansor secundariorum muscle has been shown to he altered by denervation. This muscle receives a dense, sympathetic innervation and contains high concentrations of trophic factors, which were found to be immunologically and functionally distinct from mouse Nerve Growth Factor. In young birds, denervation increased the number of neurons which could be supported by muscle extract. This difference was apparent with regard to E8 to E16 sympathetic neurons. Innervated but not denervated extract was additive with NGF in promoting neurite outgrowth. In contrast, when extracts of denervated and innervated muscle from mature birds were examined, no difference was seen in the number of neurons supported by each extract. However when the denervated and innervated extracts from mature birds were combined more neurons were supported than by a saturating dose of either extract alone. Furthermore, muscle from mature birds responded to denervation only between 2 and 9 days, whereas in young birds the effect was apparent for at least 3 weeks. Analysis of intact, control muscles during the tirst 8 weeks posthatch demonstrated that the number of neurons that could be supported by the individual extracts varied with the age of the bird.It is concluded that denervation does not in all instances lead to an increase in trophic activity, but does produce a change in the nature of the activity present, such that a different neuronal subpopulation may be supported. In addition, the response of the muscle depends on the age of the birds at the time of denervation. and this may be due to an alteration in the type of activity present in the muscle during the first few weeks after hatch.
Expression of cholinergic markers in the developing chick embryo spinal cord
Authors: Thiriet G. , Kempf J. , Ebel A. 
Published: April 2003

AbstractThe expression of cholinergic neurotransmission in the developing spinal cord was followed with pre‐ and postsynaptic cholinergic markers and histoautoradiographic determinations of cholinergic receptors and ultrastructural studies.Two distinct steps in the development of cholinergic markers were evident. The first step of cholinergic expression occurs early in development and is characterized by a sudden and large increase in choline acetyltransferase activity, whereas the high affinity choline uptake mechanism remains undetectable and few muscarinic receptors are detectable. This phenomenon possibly reflects the expression of high choline acetyltransferase gene activity in developing neurons which are still not synaptically connected. The second step is also characterized by a sharp rise of choline acetyltransferase activity. This rise parallels an active development of high affinity choline uptake and big increase in both number and density of muscarinic receptors. Also nicotinic receptors increase, as revealed by histoautoradiography. Specific morphogenetic events, such as the increase of synaptic junctions with postsynaptic thickenings and numerous presynaptic clear vesicles, occur at the same time. Such interactions may contribute to the full maturity of cholinergic neurotransmission of the spinal cord.
Influence of various growth factors and conditions on development of resting membrane potential and its electrogenic pump component of cultured rat skeletal myotubes
Authors: Brodie Chaya , Sampson S.R. 
Published: April 2003

AbstractThe effects of different growth factors and growth conditions were studied on the development of resting membrane potential and its electrogenic—ouabain‐sensitive—pump component in cultured rat myotubes. Resting potential and its electrogenic pump component were dependent on the initial plating density of the myotubes, both values increasing with increasing density. Medium from cells plated at high density, when used to replace the medium of low density cells, increased both the resting potential and its electrogenic pump component of low density myotubes. Treatment of myotubes with cytosine‐arabinoside delayed the appearance of [3H]ouabain binding sites and electrogenic pump component of resting potential, but by 8 days in culture there was no difference between treated and control cells. Similarly, cells plated initially in 5% horse serum developed resting potential and its electrogenic pump component more slowly than those in 15% horse serum, but by 8–10 days in vitro, the differences were no longer apparent. Chick embryo extract was found to have little, if any, influence on development of resting potential and its electrogenic pump component. We conclude that the different growth conditions and factors to the extent that they influence membrane potential, do so by altering the time of appearance of Na‐K ATPase, the activity of which contributes a considerable component to resting potential.