bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of neuronal markers in aggregating fetal rat telencephalon cells cultured in the presence of triiodothyronine
Authors: Jørgensen Ole Steen , Honegger Paul 
Published: April 2003

AbstractThe concentrations of the general neuronal markers D2‐protein (N‐CAM), D3‐protein and neuron specific enolase (NSE) in reaggregating cultures of fetal rat telencephalon cells were affected by the presence of 30 nM triiodothyronine in the defined culture medium. The extent of normal developmental changes were enhanced by triiodothyronine, as demonstrated by crossed immunoelectrophoresis. From 13 to 19 days in culture, the concentration of D2‐protein decreased, and the concentrations of both D3‐protein and NSE increased. Nerve growth factor (NGF) was without effect on the development of these general neuronal markers. However, as shown previously both triiodothyronine and NGF increased the activity of choline acetyltransferase, a marker for cholinergic neurons. The results suggest an enhanced overall differentiation of several types of telencephalon neurons in the presence of triiodothyronine, and a specific stimulation of cholinergic telencephalon neurons by NGF.
Development of gaba binding sites in chick embryo optic lobe: Effect of triton X‐100
Authors: Flores Vladimir , Rios Hugo , de Plazas Sara Fiszer 
Published: April 2003

AbstractThe temporal course of the development of GABA receptor sites in chick optic lohe was studied as a parameter of neuronal differentiation in the central nervous system. At 10 days of incubation, specific [3H]GABA binding was of 0.08 pmol/optic lobe and increased 7–8 fold between 12 and 16 days of incubation, reaching at 16 days a value of 0.60 pmol/optic lobe. This coincides with the period of arrival of the retinal fibers to the optic lobe. After this stage, the number of GABA binding sites decreased to a value of 0.35 pmol/optic lobe at hatching. After hatching a new increase appeared which reached at 5 days post‐hatching a value of 0.87 pmol/optic lobe. Scatchard analysis of the saturation binding data obtained at 16 days of incubation and at hatching revealed the presence of two binding sites: one with high affinity and the other with low affinity, while at 12 days of incubation, the earliest stage examined, only the low‐affinity binding site appeared. The high‐affinity binding site for [3H]GABA was inhibited by muscimol, GABA, and bicuculline (ic50: 0.006, 0.002 and 10 μM, respectively). These values correspond to the potencies shown by those compounds in the binding to the synaptic GABA receptor. Treatment of the synaptic membranes with Triton X‐100) showed a marked increase in the amount of specific [3H]GABA binding after 16 days of incubation reaching a 3‐fold increase at hatching. These results suggest that endogenous inhibitors of the higher affinity binding site, probably appear during this period.
The development of serotonergic raphespinal projections in Xenopus laevis
Authors: van Mier P. , Joosten H.W.J. , van Rheden R. , ten Donkelaar H. J. 
Published: April 2003

AbstractThe development of serotonin‐immunoreactive neurons in the central nervous system of Xenopus laevis larvae has been studied with special emphasis on the development of the raphe nuclei and raphespinal projections. The first serotonergic neurons were observed in the rostral part of the brain stem at stage 25, only 28 hr after fertilization. By stage 28 some 20 serotonin‐immunoreactive neurons were found in the rostral part of the brain stem, bearing small protrusions on the ventromedial side of the soma. These initial axonal outgrowths reach the rostral part of the spinal cord at stage 32. By stage 35/36 the growth cones of the descending serotonergic axons in the spinal cord have reached the level of the anus (10th to 15th myotome). Up to stage 45 the majority of the descending serotonergic axons was found in the dorsolateral part of the marginal zone of the spinal cord. After stage 45 some serotonergic axons were also found scattered over other parts of the spinal marginal zone. Collateral oranches were first observed in the caudal part of the brain stem at stage 35/36. Later they occurred also in the rostral (stage 43) and caudal (stage 50) spinal cord, usually on fibers in the ventral half of the spinal cord. The number of serotonergic neurons in the central nervous system (brain stem and hypothalamus) increased steadily throughout development until stage 45. After that the total number of serotonergic neurons in the central nervous system increased about two times faster than the number of serotonergic neurons in the raphe nuclei, due to a massive increase of serotonergic neurons in the hypothalamus.The present study shows that young, just differentiated raphe neurons already contain serotonin. The generation of these neurons appears to take place in the ventricular zone (matrix) of the brain stem between the caudal border of the mesencephalon and the entrance of the nervus octavus. From here these neurons seem to migrate to their final destination. The distribution of serotonin‐immunoreactive neurons in the brain stem suggests that a superior (not described so far in Anura) and an inferior raphe nucleus can be distinguished in Xenopus. A rostrocaudal gradient seems to be present in the production of serotonergic neurons which project to the spinal cord. Spinal projections from the raphe nuclei are particularly extensive from the nucleus raphes inferior and gradually decrease rostralwards. In the rostral part of the nucleus raphes superior almost no neurons projecting to the spinal cord are found.
Hypothalamic dopamine may play a role in inducing prolactin in pituitary cells
Authors: Hagino N. , Inoue Kinji 
Published: April 2003

AbstractThe effects of hypothalamic dopamine on the functional differentiation of prolactin cells was investigated in the developing rat brain. The treatment of pregnant rats with α‐methyl‐p‐tyrosine (tyrosine hydroxylase inhibitor) resulted in a noticeable decrease of dopamine concentration in the hypothalamus at birth and at 5 days of age of offspring. Moreover, treatment with this regimen caused a marked decrease in the population of prolactin cells and in the production of prolactin at birth and at 5 days of age of offspring. It seems, then, that hypothalamic dopaminergic neurons precede the functional differentiation of prolactin cells in the developing brains and that hypothalamic dopamine may play an important role in producing prolactin in the anterior pituitary during development.
Pharmacological evidence that effects of vasotocin on brain maturation are mediated by GABA mechanisms
Authors: Goldstein R. , Rodica Bartok 
Published: April 2003

AbstractActive sleep, brain weight as well as total lipids and galactolipids were assayed in 8‐day‐old rat pups, after daily administration (between 2 and 8 days of postnatal age) of saline, arginine vasotocin (AVT) (10−7 mg), picrotoxin (5 × 10−5 mg), valproic acid (10−5 and 10−6 mg) or of AVT+picrotoxin and AVT+valproic acid. AVT increases active sleep and decreases the weight, total lipids and the galactolipids of the brain. Although picrotoxin alone was without any apparent effects on maturational parameters, when administered together with AVT, it completely prevented AVT from producing its effects. Valproic acid had AVT‐like effects when administered in a higher dose (10−5 mg), but was without any apparent effects when administered in the lower dose (10−6 mg). However, both doses intensely potentiated the effects of AVT. Since both drugs specifically interfere with the GABAergic neurotransmission, it is concluded that AVT retards the accumulation of brain lipids by activating a GABAergic pathway.
A small subset of cortical astrocytes in culture accumulates glycogen
Authors: Rosenberg Paul A. , Dichter Marc A. 
Published: April 2003

AbstractWe are interested in identifying the target cells for norepinephrine in cerebral cortex and in characterizing the effects of norepinephrine on these target cells. Norepinephrine inhibits the incorporation of tritiated glucose into glycogen in rat cerebral cortex in dissociated cell culture. To identify which cells store glycogen in these cultures we combined glycogen cytochemistry with glial flbrillary acidic protein immunocytochemistry. Using this technique we show that cytochemically detectable glycogen is restricted to a small subset of astrocytes as well as an unidentified cell type which does not contain glial fibrillary acidic protein.These results demonstrate that only a minority of astrocytes in cortical cultures accumulate glycogen. Therefore cortical astrocytes are differentiated with respect to glycogen accumulation, an important metabolic function. We do not know if glycogen accumulation in astrocytes is a constitutive or facultative property. In either case the subset of astrocytes which accumulates glycogen might be one of the major cellular targets for norepinephrine in cerebral cortex.
Fibronectin and collagens modulate the proliferation and morphology of astroglial cells in culture
Authors: Goetschy Jean‐François , Ulrich Gabrielle , Aunis Dominique , Ciesielski‐Treska Jaroslava 
Published: April 2003

AbstractThe proliferation and morphology of astroglia derived from neonatal rat cortex and cultured in serum‐free medium on either untreated, or fibronectin‐, or collagen I‐, or collagen IV‐treated substrates were investigated using tritiated thymidine autoradiography and immunocytochemical staining of glial fibrillary acidic protein (GFAP) and actin. Modification of culture substratum with fibronectin enhanced the rate of proliferation of astroglial cells and increased the proportion of process‐bearing astroglial cells. The distribution of actin and patterns of adhesion observed were typical for motile cells. Both types of collagen decreased the proportion of astroglial cells undergoing mitosis. Many of the astroglial cells exhibited a flat morphology and displayed prominent stress fibres in the cell body and processes. The data suggest that specific interactions with the substratum modulate the proliferation and morphological behaviour of astroglial cells.
Acquisition of acoustic startle response in relation to growth and thyroid function in rats
Authors: Schneider Bernard F. , Golden Wendy L. 
Published: April 2003

AbstractThiourea was administered by gavage to pregnant and lactating rats from gestational day 18 until postnatal day 10, at doses of 100 or 250 mg per day (approximately 350 or 900 mg/kg/day). From the day after birth until postnatal day 14 the neonates were weighed, and beginning on postnatal day 10 acquisition of acoustic startle reflex was assessed. Serum thyroxine and thyrotropin were measured on postnatal day 14. High dose thiourea severely inhibited thyroid function in pups, significantly depressed body growth, and retarded development of the acoustic startle response. At the low dose there was a significant reduction in growth, but no effect on acquisition of acoustic startle reflex. Low dose pups appeared to be functionally euthyroid (free T4 and thyrotropin were not significantly different from control). In conjunction with other studies, these results strongly suggest that, while development of acoustic startle is dependent upon thyroid hormone, it is not readily affected by retarded body growth.
Ontogeny of the dopamine and cyclic adenosine‐3′: 5′ ‐monophosphate‐regulated phosphoprotein (DARPP‐32) in the pre‐ and postnatal mouse central nervous system
Authors: Foster G. A. , Schultzberg M. , Kökfelt T. , Goldstein M. , Hemmings H. C. , Ouimet C. C. , Walaas S. I. , Greengard P. 
Published: April 2003

AbstractThe ontogeny of a dopamine and cyclic adenosine‐3′:5′‐monophosphate‐regulated phosphoprotein with an apparent molecular weight of 32 kilodaltons (DARPP‐32) has been studied in the central nervous system of the prenatal, newborn and adult mouse.DARPP‐32‐immunoreactive somata were first identified at day 12 of gestation, in the primary olfactory cortex and in the ventrolateral medulla oblongata. On day 14 of gestation, neurons containing DARPP‐32‐like immunoreactivity became apparent in the caudate nucleus, olfactory tubercle, nucleus accumbens, frontoparietal cortex and the ventral medulla oblongata. During the period up to and including birth, the number of cell bodies and fibres in all these areas increased markedly. In addition, DARPP‐32‐positive neurons became visible in the olfactory nucleus, the arcuate nucleus, and DARPP‐32‐positive cells appeared in the choroid plexus of the lateral, third and fourth ventricles. DARPP‐32‐containing fibres could be seen in the median eminence, the ventrolateral thalamus, and in the striatonigral projection, descending in the internal capsule to ramify extensively in the substantia nigra. Only in the cerebellum and suprachiasmatic nucleus did the development of DARPP‐32‐like immunoreactivity occur postnatally.The development of tyrosine hydroxylase, the rate‐limiting enzyme for catecholamine synthesis, was simultaneously examined. The arrival of the tyrosine hydroxylase‐containing projection to the caudate nucleus, the olfactory tubercle and the nucleus accumbens apparently occurred 1–2 days after the appearance of DARPP‐32‐immunoreactive cells within these regions. In the ventral and ventrolateral medulla oblongata, and the primary olfactory cortex, no tyrosine hydroxylase innervation was seen near the DARPP‐32‐positive neurons at days 12–14. The organization of the DARPP‐32‐containing somata of the caudate nucleus into aggregates of 5–15 neurons was partly paralleled spatially by an increased density of tyrosine hydroxylase‐positive fibres.Many DARPP‐32‐immunoreactive cells in the immature mouse brain are present by the day of birth, particularly in the areas known to receive a dopaminergic innervation. The development of these presumptive dopaminoceptive DARPP‐32‐containing neurons does not seem to be dependent on the presence, however, of a dopaminergic input, since in all regions examined DARPP‐32‐LI preceded the appearance of tyrosine hydroxylase‐like immunoreactivity by at least 1–2 days. Indeed, the results suggest that the existence of DARPP‐32‐like immunoreactivity in cell bodies and dendrites may be a pre‐requisite for the formation or subsequent stabilization of dopaminergic synapses.
DNA content in neurons of Auerbach's plexus under experimental conditions in adult rats
Authors: Robecchi M. G. Giacobini , Poncino A. , Geuna S. , Giacometti S. , Filogamo G. 
Published: April 2003

AbstractSome nerve cells of the Auerbach's myenteric plexus of the intestine of the adult rat, which hypertrophied following a surgically induced stenosis, began DNA synthesis unrelated to mitotic division.The cytophotometric analysis confirmed and quantified the amount of synthesis revealed by autoradiography with tritiated thymidine uptake.Numerous nerve cells show a DNA content exceeding the diploid level. Only a few of these show twice the diploid content.The significance of the DNA synthesis is discussed.
GABA agonist promoted formation of low affinity GABA receptors on cerebellar granule cells is restricted to early development
Authors: Belhage B. , Hansen G. H. , Schousboe A. , Meier E. 
Published: April 2003

AbstractThe ability of the GABA receptor agonist 4,5,6,7‐tetrahydroisoxazolo[5,4‐c]pyridin‐3‐ol (THIP) to promote formation of low affinity GABA receptors on cerebellar granule cells was tested using primary cultures of these neurons. Granule cells were exposed to THIP (150 μM) for 6 hr after, respectively, 4, 7, 10 and 14 days in culture. It was found that THIP treatment of 4‐ and 7‐day‐old cultures led to formation of low affinity GABA receptors, whereas such receptors could not be detected after THIP treatment in the older cultures (10 and 14 days) in spite of the fact that these cultured granule cells expressed a high density of high affinity GABA receptors. It is concluded that the ability of THIP to promote formation of low affinity GABA receptors on cerebellar granule cells is restricted to an early developmental period.
Role of glucocorticoids in the chromaffin‐neuron developmental decision
Authors: Anderson David J. , Michelsohn Arie 
Published: April 2003

AbstractChromaffin cells and sympathetic neurons develop from a common neural crest‐derived progenitor cell. The developmental fate of this cell differs depending upon whether it migrates to the sympathetic ganglion or to the adrenal gland primordium, suggesting that local environmental signals control its differentiation. Glucocorticoid (GC) is a good candidate for an important adrenal environmental signal. These steroids are known to regulate PNMT, an adrenal‐specific enzyme. However, in vivo observations suggest that the adrenal microenvironment influences the phenotype of sympathoadrenal progenitor cells as early as E14.5, 2 days before PNMT is first expressed by developing chromaffin cells. Using cDNA probes, we find that GC receptor mRNA can be detected in the embryonic adrenal at least one full day before the initial appearance of PNMT mRNA. This observation is compatible with the idea that the apparent early influence of the adrenal microenvironment reflects the action of GC on progenitors which have migrated into this environment. In support of this, we show that similar influences can be exerted by GC on PC12 cells, which contain GC receptor mRNA but do not express or induce PNMT mRNA. Taken together, these data suggest that other factors in addition to the presence of the GC receptor may be necessary for the developmental appearance of PNMT expression.
In vitro evidence for a neurite growth‐promoting activity in trembler mouse serum
Authors: Koenig J. , Hantaz‐Ambroise Dj. , De La Porte S. , Thi N. A. Do , Bourre J. M. , La Chapelle F. , Koenig H. L. 
Published: April 2003

AbstractBasal lamina components, such as heparan sulfate proteoglycan (HSPG) and laminin play an important role in neuritic outgrowth for CNS and PNS neurons in culture. The mutant mouse ‘Trembler’ is characterized by hypomyelinization and production of an excess of basal lamina layers around Schwann cells in peripheral nerves.In order to analyse whether or not the serum of the mutant animals contains neurite outgrowthpromoting factors, we cultured rat spinal cord neurons in the presence of Trembler serum. Under these conditions, the outgrowth of neurites was increased approx, 2 times as compared to control serum. Trembler serum induces neuritic outgrowth characterized both by an increase in number of primary neurites emerging from the nerve cell body as well as by an increase in peripheral branching of neurites.To characterize the factors implicated in this increase we added antibodies directed against HSPG or laminin to the mutant serum. As a result, the increase in neuritic outgrowth was reduced or abolished in both cases.Trembler effect on neurite growth disappeared when the number of the non‐neuronal cells was reduced, suggesting that the mutant serum did not act directly on neurons but by the intermediary action of non‐neuronal cells.
Commissural size in neonatal rats: Effects of sex and prenatal alcohol exposure
Authors: Zimmerberg Betty , Scalzi Lisabeth V. 
Published: April 2003

AbstractSex differences have been reported in the size of the adult corpus callosum in both humans and rodents. This experiment investigated whether sex and/or different prenatal treatment conditions would influence commissural size at birth. Male and female 3‐day‐old Long Evans rats were selected from one of three prenatal treatment histories: prenatal alcohol‐exposed (35% ethanol‐derived calories, 35% EDC), nutritional control (0% ethanol‐derived calories, 0% EDC) or standard control (lab chow). Midline sagittal areas of the corpus callosum and the anterior commissure were determined for these subjects. Male control subjects had significantly larger callosal areas than females. Prenatal alcohol exposure significantly abolished this sexual dimorphism, with 35% EDC males having a significantly smaller callosal area than males from both control groups. This effect was independent of prenatal treatment differences in body or brain size. There were no significant sex differences in the midline sagittal area of the anterior commissure, nor were there any apparent effects of prenatal treatment on this measure. These results indicate that sex differences in the size of the corpus callosum are present at birth. Since a difference in myelination cannot account for this difference in area, there may be a sex difference in the number of fibers or in the average fiber size. Additionally, the effects of prenatal alcohol exposure on male, but not female, offspring suggest that this alcohol‐related birth defect is hormonally mediated.
The ontogeny of [3H]5‐hydroxytryptamine binding in the lamb: Effects of in vivo thyroidectomy
Authors: Richards Gail E. , Lakoski Joan M. , Black Eric W. , Halpern Rebekah E. , Ball Karen , Gluckman Peter D. 
Published: April 2003

AbstractThe effects of congenital hypothyroidism in the late gestation ovine fetus include changes in serotonin concentrations in specific brain areas. To investigate possible ontogenic patterns of changes in 5‐HT receptor function, we studied the binding characteristics of [3H]5‐HT in the midbrain, hypothalamus and cerebral cortex in the late gestation ovine fetus and young lamb. We compared the binding characteristics of control fetuses to those of thyroidectomized fetuses, with or without thyroxine replacement therapy.In each of the areas examined, age‐dependent changes in the receptor density (Bmax) for [3H]5‐HT was observed. In cerebral cortex, Bmax was constant from 120 days gestation through the early neonatal period and increased significantly only at 25–30 days after birth. In hypothalamus, [3H]5‐HT binding density decreased late in gestation (140–145 days) with a return after birth to values comparable to those at 120–125 and 130–135 days gestation. The midbrain also exhibited a significant age‐dependent pattern of altered receptor density with a decrease in the 130–135 and 140–145 day gestational age groups compared to both younger and older lambs. In contrast, the affinity constant (Kd) for [3H]5‐HT did not change over the ages evaluated in cerebral cortex or hypothalamus. In the midbrain. however, there was a significant increase in Kd at 1–5 days after birth compared to all other age groups. The ability of fetal thyroidectomy, with or without thyroxine replacement therapy, to alter patterns of [3H]5‐HT binding was also tested. In the hypothyroid animals, examined at 130–135 days gestation, both the cerebral cortex and midbrain receptor affinities (Kd) were the same as control animals and animals of the same gestational age which had undergone throidectomy followed 10 days later by thyroxine treatment. In contrast, the receptor density (Bmax) for [3H]5‐HT was increased significantly in the midbrain of both thyroidectomy animals and animals which had thyroidectomy plus thyroxine treatment.These data demonstrate marked patterns of ontogenic change in characteristics of [3H]5‐HT binding, particularly in the midbrain region of this species. In addition, these studies support the hypothesis that changes in 5‐HT receptor binding which result from hypothyroidism may be an index of thyroiddependent brain maturation.