bluuebunny/crossref_metadata_2025_split huggingface dataset:
GABA influences the ultrastructure composition of cerebellar granule cells during development in culture
Authors: Hansen Gert H. , Meier Eddi , Schousboe Arne 
Published: April 2003

AbstractThe influence of GABA on cerebellar granule cells in culture was followed morphometrically during in vitro development by growing the cells in the absence or presence of 50 μM GABA. The presence of GABA in the culture media increased the number of neurite‐extending cells by 50% after 7 days in culture. At the ultrastructural level GABA treatment led to an increased density of neurotubules, rough endoplasmic reticulum, Golgi apparatus, coated vesicles and other vesicles, whereas structures such as mitochondria and smooth endoplasmic reticulum were not affected by GABA. The density of free ribosomes showed a more pronounced tendency to decrease as a function of the culture period (1–7 days) when the cells were grown in the presence of GABA as compared to control cultures. The results strongly indicate that GABA in addition to being an important neurotransmitter serves as a trophic factor in the development of at least certain types of neurons.
Monosialoganglioside internal ester stimulates the dopaminergic reinnervation of the striatum after unilateral hemitransection in rat
Authors: Aldinio Caterina , Valenti Giacomina , Savoini Gian Enrico , Kirschner Guenter , Agnati Luigi F. , Toffano Gino 
Published: April 2003

AbstractThe effects of the administration of GM1 monosialoganglioside internal ester, AGF2, on the dopaminergic reinnervation of the striatum in rats with unilateral hemitransection has been studied. AGF2 increases the apparent Vmax and the density of tyrosine‐hydroxylase‐positive nerve terminals in the striatum of the lesioned side, without modification of the tyrosine‐hydroxylase activity in the unlesioned side. AGF2, at lower doses, is more active than its parent natural molecule GM1. AGF2 has a larger half‐life and a higher distribution volume than GM1, and undergoes a slow hydrolysis in the serum releasing the original natural compound GM1. Mannitol and dexamethazone, often used to prevent swelling of the brain after injury, or isoaxonine, proposed to stimulate neurite growth are unable to reproduce the effects of AGF2 on the recovery of striatal tyrosine‐hydroxylase activity after hemitransection. The data are compatible with the view that AGF2, through its conversion into GM1, facilitates the collateral sprouting of the nigro‐striatal dopaminergic neurons.
Modification of taurine and hypotaurine uptake systems in cultured primary astrocytes by serum‐free medium and dibutyryl cyclic AMP treatment
Authors: Holopainen I. 
Published: April 2003

AbstractThe characteristics of taurine and hypotaurine uptake were studied during astrocyte maturation in cultures grown in normal, serum‐containing medium or in serum‐free medium in the presence of 0.1 mmol/l dibutyryl cyclic AMP (dBcAMP). The uptake of both amino acids consisted of one saturable high‐affinity component in both control and treated cultures. The dBcAMP treatment produced no marked modification of the transport systems. In the treated cultures the kinetic parameters of taurine and hypotaurine uptake remained unaltered during maturation. In the control cells the transport constant and maximal velocity of taurine uptake were greater in 21‐day‐old than in 16‐day‐old cultures, while the changes in hypotaurine transport were the opposite. The uptakes were strictly sodium‐dependent and also considerably decreased when potassium ions were omitted from incubation medium. The uptake of both amino acids was affected more by potassium omission in the dBcAMP‐treated than in the control cultures. Also the results with metabolic poisons suggest that physiological ion gradients sustained by an active Na+, K+‐pump are essential for the normal uptake of taurine and hypotaurine.
Comparison of embryonic and adult torpedo acetylcholine receptor by sedimentation characteristics and antigenicity
Authors: Holton Beatrice , Tzartos Socrates J. , Changeux Jean‐Pierre 
Published: April 2003

AbstractThe acetylcholine receptor (AChR) from Torpedo marmorata electric organ exists in a light form (α2βγδ) of apparent molecular weight 250,000. The association of two light forms via an intermolecular δ‐δ disulfide bridge results in the AChR heavy form. In adult Torpedo electric organ extracts the heavy form constitutes about 70% of the AChR. We report that, in contrast, embryonic electric organ extracts contain only about 30% of the heavy form, the rest being light form. In addition, amongst a library of 38 monoclonal antibodies (mAbs), all of those that distinguished between embryonic and adult AChR did so only because they precipitated the heavy form of the AChR better than the light form.
Effect of hydrocortisone on the number of small intensely fluorescent cells in the rat superior cervical ganglion during pre‐ and postnatal development
Authors: Päivärinta H. , Soinila S. , Eränkö O. 
Published: April 2003

AbstractDuring the first postnatal week hydrocortisone causes a massive increase in the number of small intensely fluorescent (SIF) cells. The purpose of the present study was to investigate whether the number of SIF cells can be increased with hydrocortisone also prenatally and after the first postnatal week.Because it was desirable to apply the same kind of treatment before and after birth, the embryos and neonatal rats were injected only once and were studied 4 days later. Pregnant rats were injected daily during the last 7 days of pregnancy and the superior cervical ganglia of their embryos were studied thereafter. After birth, the effect of 7 daily injections of hydrocortisone was also studied.The number of embryonal brightly fluorescent cells, the probable prenatal precursors of the SIF cells. could not be increased either with a single injection into the embryos, or in embryos of pregnant rats treated with hydrocortisone. A single injection of hydrocortisone into newborn and 4‐day‐old rats caused a massive increase in the number of SIF cells as studied in 4‐ and 8‐day‐old rats, respectively. The increase in the number of SIF cells was smaller but still statistically significant in 12‐day‐old rats injected with hydrocortisone on postnatal day 8. Daily injections of hydrocortisone for 7 days caused on the second, but not on the third postnatal week, a statistically significant increase in the number of SIF cells.After 7 injections of hydrocortisone. on postnatal days 3–9 or 40–46. no increase in the number of SIF cells was observed in 47‐day‐old rats, as compared with saline‐treated controls of the same age, but 7 injections of hydrocortisone both on days 3–9 and 40–46 resulted in a significant increase in the number of small intensely fluorescent cells on day 47.It is concluded that hydrocortisone‐induced increase in the number of SIF cells is limited in vivo to the first two postnatal weeks, while exposure to hydrocortisone at birth restores the responsiveness of these cells to increase in number even later after a second exposure to hydrocortisone.
Differentiation of neurons and radial glia in the spinal cord of the teleost Brachydanio rerio (the zebrafish): An immunocytochemical study
Authors: van Raamsdonk W. , Heyting C. , Pool C.W. , Smit‐Onel M.J. , Groen J.L. 
Published: April 2003

AbstractThe differentiation of neurons and glial cells in the spinal cord of the zebrafish was studied by means of immunohistochemistry, using antisera against the 68 kD subunit of neurofilament (anti‐NFP68) and against glial fibrillary acidic protein (anti‐GFAP), both isolated from the bovine brain. Anti‐NFP68 and anti‐GFAP reactivity appear in the spinal cord at about 60 h after fertilization. At that time the anti‐NFP68 reactivity is detectable in the dorsal Rohon‐Beard neurons. About 12 h later, NFP68 positive neurons appear in the prospective motor column. In this respect the differentiation of the primary sensory system precedes that of the spinal motor system. During development the configuration of the glial cell processes changes from a horizontal arrangement in embryos to a radial frame work in larvae and in adults. From these observations together with data on the organization of the adult spinal motor column28 we conclude that the motoneurons of the white and those of the red myotomal muscle fibers may have different origins in the neuroepithelial germinal layer. The anti‐NFP68 serum recognizes a 120 and a 94 kD component of fish neurofilaments. Thus the subunit composition of neurofilament in fishes differs from that in mammals.
Association of laminin and other basement membrane components with regions of high acetylcholine receptor density on cultured myotubes
Authors: Daniels Mathew P. , Vigny Marc , Sonderegger Peter , Bauer Hans‐Christian , Vogel Zvi 
Published: April 2003

AbstractThe distribution of immunoreactivity to basement membrane components in cultures of rat skeletal myotubes was compared to acetylcholine receptor distribution by fluorescence microscopy. Laminin occurred in patches on the myotube surface, and most laminin patches coincided or overlapped with acetylcholine receptor aggregates. Almost all receptor aggregates coincided with laminin patches. Most of the heparan sulfate proteoglycan and fibronectin was associated with non‐muscle cells, but some patches coincided with receptor aggregates on myotubes. In cultures treated with l‐ascorbate, collagen types IV and V covered much of the myotube surface and receptor aggregates often coincided with intense collagen patches. When receptor aggregation was induced by treatment of cultures with soluble neural factors, the newly formed receptor aggregates coincided with laminin patches.The results suggest that each of the basement membrane components studied has a distinct distribution pattern in primary rat muscle cell cultures. The striking association of laminin immunoreactivity with receptor aggregates, together with the enhancement of receptor aggregation by laminin reported previously (Vogel et al., J. Neurosci. 3, 1058–1068, 1983) suggests that laminin could have a role in the organization of acetylcholine receptors on developing muscle fibers.
Immunohistochemical analysis of the ontogeny of neuropeptide Y immunoreactive neurons in foetal rat brain
Authors: Foster G.A. , Schultzberg M. 
Published: April 2003

AbstractThe development of neuropeptide Y‐like immunoreactive structures in the foetal rat brain was investigated by means of the indirect immunohistofluorescence technique.Neuropeptide Y‐like immunoreactive cells and fibres first appeared on day 13 of gestation, in the solitary tract nucleus, lateral reticular nucleus and nucleus ambiguus in the medulla oblongata, and in the primordial inferior colliculus and deep mesencephalic nucleus. Thereafter, neuropeptide Y‐like immunoreactive cells and fibres increased in number in many areas including the primary olfactory cortex, the frontoparietal, somatosensory cortex, caudate putamen, lateral hypothalamus, ventrolateral thalamus, amygdala and parafascicular nucleus. The maximum number of cells over the age range studied, namely day 12 of gestation to birth day, occurred at around day 21. On the day of birth, accordingly, there were significantly fewer neuropeptide Y‐like immunoreactive cell bodies in a number of brain areas, the most striking deficit being in the ventrolateral thalamus.The present study demonstrates the very early appearance of neuropeptide Y‐like immunoreactive structures during foetal brain development. The functional role of the peptide during this period remains, however, to be determined.
Postnatal development of rat cerebellum: Glycosaminoglycan changes related to variation in water content, cell formation and organ growth
Authors: Normand G. , Clos J. , Vincendon G. , Gombos G. 
Published: April 2003

AbstractModifications of glycosaminoglycans were studied during rat cerebellum ontogenesis. Levels of both hyaluronic acid and sulphated glycosaminoglycans increase during development but not at the same rate as cerebellar size or proteins. As in the rest of the brain, cerebellar hyaluronic acid concentration decreases during development but not, as expected, in parallel with the loss of tissue water content. In contrast to forebrain, the concentration of cerebellar sulphated glycosaminoglycans decreases at a slow rate. The correlation, suggested by several authors, between glycosaminoglycans concentration and tissue hydratation, cell migration and myelination were not confirmed in developing rat cerebellum.
Effects of thyroid deficiency on the development of cholinergic, GABA, dopaminergic and glutamate neuron markers and DNA concentrations in the rat corpus striatum
Authors: Kalaria Rajesh N. , Prince Alan K. 
Published: April 2003

AbstractThe effects of propylthiouracil (PTU)‐induced thyroid deficiency on the postnatal development of synaptic markers for cholinergic, GABA, dopaminergic and glutamate neurons in the rat corpus striatum were investigated. Similar effects were also assessed on β‐alanine uptake by fine prisms and on DNA concentrations in striatal samples from 3‐ and 6‐week‐old rats. Thyroid deficiency (Tx) in rats markedly impaired the development of choline acetyltransferase activity and [3H]spiroperidol and [3H]‐glutamate binding capacities. In contrast, small but significant increases were evident in γ‐aminobutyric acid uptake and glutamate decarboxylase activity. β‐Alanine uptake, a possible glial marker, was increased by up to 50% in samples from the Tx rats compared to controls. Consistent with deficits in striatal weight and greater DNA concentrations in the striatum of the Tx rats those neuronal markers which showed impairments on a mg tissue basis manifest even greater impairments expressed per whole striatum. Present findings suggest differential effects on neuronal markers, with the greatest impairments in the presynaptic markers for cholinergic interneurons in striatum during neonatal thyroid deficiency. The differential sensitivity on neuronal markers of the relatively late onset of thyroid deficiency seems likely to reflect the timing of the morphological differentiation of cholinergic and the other neurons in striatum.
Oligodendrocyte production and myelin recovery in heterozygous jimpy mice: An autoradiographic study
Authors: Rosenfeld Jeffrey , Friedrich Victor L. 
Published: April 2003

AbstractJimpy is a genetic disorder of mouse resulting in hypomyelination. In this study oligodendrocyte proliferation was examined in heterozygous carriers of the jimpy gene. The incorporation of [3H]‐thymidine into DNA is increased in jimpy heterozygotes compared to controls. An autoradiographic analysis indicated that oligodendrocytes are the predominant neuroglial cell type being produced in the brain at the ages studied in both heterozygotes and control animals. In addition, the total number of labeled oligodendrocytes was increased in the heterozygote animals compared to controls. These results, taken together, indicate that the rate of oligodendrocyte production is greater in jimpy heterozygotes than in control animals.We have previously shown that young jimpy heterozygotes have a reduced myelin content and older heterozygotes do not. The increased rate of oligodendrocyte production, demonstrated in this study, is most likely responsible for the increasing myelin content in the heterozygote.Further study of the cellular interactions which trigger oligodendrocyte production and myelin recovery in the jimpy heterozygote may be relevant to remyelination in other disease states, including those affecting humans.
Developmental aspects of polyamine interconversion in rat brain
Authors: Bolkenius F.N. , Seiler N. 
Published: April 2003

AbstractIn the mammalian organism putrescine is formed by two reactions: (a) decarboxylation of ornithine and (b) degradation of spermidine via the so‐called interconversion pathway. The latter comprises N1‐acetylation of spermidine by a cytosolic acetyltransferase. and oxidative splitting of N1‐acetylspermidine to putrescine by polyamine oxidase (PAO). It has previously been shown that specific inhibition of PAO causes a time‐dependent accumulation of N1‐acetylspermidine in brain, which is a measure of spermidine turnover. Another consequence of PAO inhibition is the decrease of brain putrescine concentration, proportional to its normal formation from spermidine. This observation allowed us to demonstrate the increasing significance of polyamine interconversion with brain maturation. The results support our hypothesis that the mechanisms which regulate cellular polyamine concentrations change during normal brain maturation from a system in which l‐ornithine decarboxylase is dominating to a more sophisticated system in which both synthetic and catabolic processes become equally important regulatory factors.In contrast with current views, the activity of S‐adenosylmethionine decarboxylase rather than that of ornithine decarboxylase limits the rate of polyamine biosynthesis during early brain development. In the mature brain the total amount of putrescine, which is formed both by decarboxylation of ornithine and by degradation of spermidine, limits the rate of spermidine formation. Changes of the regulatory system analogous to those described in this work are presumably not exclusive for brain, but rather characteristic for a variety of differentiating cells.
Neurogenesis in the rat primary olfactory cortex
Authors: Bayer Shirley A. 
Published: April 2003

AbstractNeurogenesis in the rat primary olfactory cortex was examined with [3H]thymidine autoradiography. The experimental animals were the offspring of pregnant females given an injection of [3H]thymidine on two consecutive gestation days. Nine groups of embryos were exposed to [3H] thymidine on E13–E14, E14–E15, … E21–E22, respectively. On P60, the percentage of labeled cells and the proportion of cells originating during 24 hr periods were quantified at selected anatomical levels of the anterior and posterior piriform cortex, dorsal lateral peduncular cortex, and posterior two‐thirds of the ventral agranular insular cortex. Throughout most of the primary olfactory cortex, deep cells are generated earlier than superficial cells: the ‘dinside‐out’ pattern. Neurons in the anterior (prepiriform) cortex are located lateral to the caudal anterior olfactory nucleus and olfactory tubercle, and are generated mainly between E14 and E18 in a caudal (older) to rostral (younger) neurogenetic gradient. Neurons in the posterior (periamygdaloid) cortex are located lateral to the caudal olfactory tubercle and amygdala, and are generated mainly between E14 and E17 simultaneously along the rostrocaudal plane. Superficial cells in the piriform cortex have some additional neurogenetic gradients; ventromedial cells forming transition zones with either the olfactory tubercle or amygdala originate earlier than cells located dorsally and laterally. In the posterior piriform cortex, younger neurons are located at middle dorsoventral levels while older neurons lie above and below. Neurons in the dorsolateral peduncular cortex originate between E14 and E20 in a caudal to rostral gradient of neurogenesis; caudal parts also have a lateral to medial neurogenetic gradient. The most lateral part of the dorsolateral peduncular cortex is unique and does not have the typical ‘inside‐out’ cortical neurogenetic gradient. Neurons in the ventral agranular insular cortex (area 13) originate mainly between E15 and E17 in combined caudal to rostral and ventral to dorsal neurogenetic gradients. The neurogenetic gradients in the primary olfactory cortex, along with patterns of neurogenesis throughout the olfactory projection field are related to the termination patterns of afferents from the main olfactory bulb.
Current aspects of the development of the blood‐brain barrier
Authors: Joó Ferenc 
Published: April 2003

AbstractResults of earlier studies clearly indicated that, during development, a number of enzymes are sequentially expressed in the brain endothelial cells correlating in time with the maturation of brain tissue. More recent data suggested that differentiation of endothelium in the intraparenchymal cerebral microvessels into one with blood‐brain barrier characteristics seems to be induced by astrocytes at a specific time of embryonic development. Details of the above‐mentioned and other important aspects of the development of the blood‐brain barrier will be discussed in the present mini review.
Axonal maturaion in development—I. Characterization of monoclonal antibodies reacting with axon‐specific neurofilament epitopes
Authors: Dahl D. , Gardner E. E. , Crosby C. J. 
Published: April 2003

AbstractMonoclonal antibodies reacting with the high molecular weight neurofilament polypeptides (NF 150K and NF 200K) were obtained upon immunization with NF 150K and NF 200K isolated from bovine spinal cord by anion exchange chromatography. The five monoclonal antibodies obtained with NF 200K stained only axons. With three monoclonals the reactivity was abolished by digestion with phosphatase and by dilution of the supernatants in sodium potassium phosphate. The nine monoclonal antibodies obtained upon immunization with NF 150K stained both high molecular weight neurofilament polypeptides on immunoblots of bovine and rat spinal cord extracts with the exception of one monoclonal only reacting with the homologous antigen. The antibodies could be divided into two groups, axon‐specific and conventional. Conventional antibodies decorated neurofilaments regardless of their location, i.e. axons, perikarya and dendrites. With all these antibodies the immunostaining was not affected by phosphatase digestion of neurofilament protein nor by dilution of the supernatants in sodium potassium phosphate. Axon‐specific antibodies reacting with both NF 150K and NF 200K in rat spinal cord only stained the heterologous antigen (NF 200K) in rat optic nerve and sciatic nerve extracts. We suggest that some axon‐specific neurofilament antibodies recognize neurofilament modifications other than phosphorylation; or, alternatively that they react with phosphorylated epitopes not accessible to phosphate or to exogenous phosphatases. Furthermore, we suggest that some neurofilament modifications do not occur uniformly throughout the nervous system.
Chromaffin cell proliferation in the adult rat adrenal medulla
Authors: Tischler Arthur S. , Ruzicka Laurel A. , Donahue Stephen R. , DeLellis Ronald A. 
Published: April 2003

AbstractEpinephrine and norepinephrine‐containing chromaffin cells proliferate in the adrenal glands of normal adult rats throughout life. Moreover, their rate of proliferation is markedly increased by short‐term administration of reserpine, one of many agents which in long‐term experiments are associated with the development of adrenal medullary tumors. Current data suggest that chromaffin cell proliferation in the adult rat adrenal is mediated by the interaction of neurogenic and hormonal signals. Reserpine is known to directly deplete catecholamine stores, and to reflexively increase the activity of the splanchnic nerve endings innervating the adrenal medulla to stimulate both secretion and synthesis of catecholamines and other secretory granule constituents. Its effect on chromaffin cell proliferation suggests that the same signals may regulate chromaffin cell number to meet physiological needs. The reserpine model might shed light on signal transduction mechanisms which normally promote or prevent proliferation of chromaffin cells and of other neuroendocrine cells during development or in adult life, and on ways in which such mechanisms are altered in the course of the development and progression of tumors. It also suggests the possibility that chromaffin cells might be propagated in vitro for use in basic biological studies or in transplants for the treatment of Parkinson's disease.