bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and distribution of serotonin in the central nervous system of Manduca sexta during embryogenesis I. The brain and frontal ganglion
Authors: Radwan Wafaa A. , Granger Noelle A. , Lauder Jean M. 
Published: April 2003

AbstractDevelopment of the serotonergic system in the brain and frontal ganglion of the Manduca embryo between 35 and 100% of development was studied immunocytochemically with an antiserum to serotonin (5‐HT). Serotonin immunoreactivity was initially detectable at 40–45% development in short fibers in the head region, prior to differentiation of the brain. Immunoreactive cell bodies were first seen in the brain at 60% development, located in the protocerebrum and tritocerebrum. Thick fiber tracts crossing the midline (commissures) could also be observed at this early stage. As development of the embryo progressed, eight immunoreactive cell groups, containing a total of about 38–40 cells and four commissures with terminal arborizations appeared successively in the brain. From 75 to 100% development, no obvious changes occurred in the number or distribution of cells and the brain exhibited the same pattern of 5‐HT immunoreactive cells, fiber tracts and arborizations as in last instar larvae of Manduca. However, an increase in the size of the cells in both the brain and frontal ganglion was noted between 75 and 80% development, followed by a decrease by 100% development. The frontal ganglion was found to contain three 5‐HT immunoreactive cells, which appeared to send bilateral projections into the frontal connectives and the recurrent nerve. During embryonic development, the dendritic arborizations of these frontal ganglion cells increased, while the amount of 5‐HT immunoreactivity in the cell bodies decreased. Thus, the serotonergic system first appears in the Manduca embryo at an early stage of development, similar to the situation in other insects as well as vertebrates. By the end of the embryonic period, the same number of serotonergic neurons are present in the brain as in larval and adult Manduca, suggesting that once formed, these cells persist through postembryonic development and metamorphosis.
In vitro screening for anticonvulsant‐induced teratogenesis in neural primary cultures and cell lines
Authors: Regan C. M. , Gorman A. M. C. , Larsson O. M. , Maguire C. , Martin M. L. , Schousboe A. , Williams D. C. 
Published: April 2003

AbstractTo establish inherent potential for the induction of neural tube defects the ability of selected anticonvulsant agents to interfere with cell division has been established in vitro using an antiproliferative assay in clonal cell lines and a cytotoxicity assay using primary cultures of cerebral cortex neurons at different stages of development. In order to evaluate the relative toxicities of these agents their in vitro effects were determined at 2–3 times the plasma therapeutic level. By these procedures valproate and the benzodiazepines, diazepam and clonazepam, exerted a potent antiproliferative action which could not be attributed to increased cytotoxicity. In contrast phenytoin was markedly cytotoxic but was without an antiproliferative action. This cytotoxicity was most pronounced during the periods of extensive fibre outgrowth. When compared to epidemiological and animal study data, agents which inhibited cell proliferation within twice therapeutic concentration were consistently associated with major neural tube malformations. However phenytoin, found to be positive in the cell cytotoxicity assay, is not associated with neural tube malformations but rather is primarily associated with mental retardation. Thus assessment of antiproliferative activity of anticonvulsant drugs may be one criterion for identification of teratogenic potential during neurulation.
Immunocytochemical study of S‐100 positive glial cells in the brainstem and spinal cord of the rat embryo
Authors: Gomez Luciano Ariel , Brusco Alicia , Saavedra Jorge Pecci 
Published: April 2003

AbstractA light and electronmicroscopic immunocytochemical study of the glial cells in the brainstem and spinal cord of the 18th day rat embryo was performed using an anti‐S‐100 protein antiserum. Only the radial glia and the free immature glial cells are S‐100 immunoreactive. Neurons are devoid of S‐100 immunoreactivity. The radial glia form two paramedial plates and a great number of lateral plates, uniformly spaced along the ventral portion of the brainstem from the mesencephalon to the medulla. The S‐100 protein was also detected in the perivascular membranes and glial limitans. Embryonic glia adopt a highly organized spatial pattern in the brainstem that could set the structural basis for an organized assembly of the developing nervous tissue. The use of the S‐100 protein as a glial marker in the embryonic rat brain proved to be of great value. Antibodies to S‐100 protein allow the demonstration of immature glial cells and a highly organized spatial pattern in the brainstem and spinal cord of the rat embryo.
Cerebral ornithine decarboxylase levels following gestational exposure to cocaine
Authors: Bondy S. C. , Nakla M. , Ali S. F. , Ahmad G. 
Published: April 2003

AbstractThe pre‐ and postnatal developmental course of cerebral ornithine decarboxylase (ODC) has been studied in infant rats after treatment of pregnant dams with cocaine. Levels of cocaine attained in brains and serum of embryos were not initially increased over corresponding maternal values, but were more persistent. However, cocaine was no longer detectable in these tissues 4 days after administration. The cerebral ODC level of treated pups was initially depressed and subsequently elevated relative to control values. These changes were apparent at times when cocaine was not detected in the developing brain. Results indicate that a transient exposure to cocaine in utero may lead to prolonged developmental abnormality.
Motor nerve terminal restoration after focal destruction in young and old mice
Authors: Robbins Norman , Kuchynski Marie , Polak Joseph , Grasso Alfonso 
Published: April 2003

AbstractRegeneration of soleus motor nerve terminals after focal destruction by black widow spider venom (BWSV) or its active factor alpha‐latrotoxin (LTx) was compared in young and old CBF‐1 mice. The object was to determine whether previously reported delayed regeneration after nerve injury in old rodents was due to altered removal of debris, or delay or aberrancy in structural or functional restoration of the neuromuscular junction. In addition, the use of a new fluorescent technique permitted for the first time quantitation of the accuracy of early nerve terminal regeneration in mammalian muscle. Immunohistochemical and electron micrographic studies showed no age difference in destruction of terminals and removal of debris 2 days after toxin application. The indirect twitch and structural reinnervation (measured with flourescent techniques) returned to an equal extent in young and old mice beginning at 3 days after LTx treatment. BWSV (as opposed to LTx) delayed regeneration 1 day in young but not in old mice. On the first day of reinnervation, there was perisynaptic outgrowth in both young and old mice, although in the latter, there was a higher incidence of aberrant outgrowth. The relation between return of twitch strength and recovery of nerve terminal area (measured in teased zinc iodide‐stained preparations) showed no age dependency. We conclude that factors cited to explain altered reactive sprouting in the aging CNS do not apply to regeneration of peripheral motor nerve terminals. However, it is possible that the aberrant regrowth observed at the neuromuscular junction in old mice will pertain to the aging CNS. Altered axonal rather than nerve terminal regeneration is the likely source of delayed peripheral nerve regeneration in old animals.
Aging and stress‐induced changes in choline and glutamate uptake in hippocampus and septum of two rat strains differing in longevity and reactivity to stressors
Authors: Gilad Gad M. , Gilad Varda H. , Tizabi Yousef 
Published: April 2003

AbstractStress induced changes in neurochemical indices of neurotransmission are more pronounced in the septohippocampal cholinergic system of Wistar Kyoto rats, which are behaviorally more reactive to Stressors and have a shorter life span, than in Brown Norway rats. Moreover, pronounced degeneration of septohippocampal cholinergic neurons occurs earlier in life in Wistar Kyoto rats. In the present study the high affinity synaptosomal uptakes of choline and glutamate were used as indices for cholinergic and glutamatergic systems respectively. Following 2 hr of mild restraint stress increases in both uptake systems were observed in all regions examined (hippocampus, septum and frontal cortex). The stress‐induced increases were generally similar in young (3 months) and aged (20 months) rats of both strains. The noted exception was that choline uptake levels, which were reduced in the hippocampus of unhandled aged WKY rats, remained unchanged after stress. The results confirm the involvement of the septohippocampal cholinergic system in the response to acute stress and extend the findings to include the hippocamposeptal glutamatergic system activation as well. It is suggested that in spite of neuronal degeneration during aging, these responses to stress can be maintained by compensatory efforts of neurons that remain intact.
Influence of development and aging on nicotinic receptor subtypes in rodent brain
Authors: Zhang Xiao , Wahlström Göran , Nordberg Agneta 
Published: April 2003

AbstractThe influence of development and aging on nicotinic receptor subtypes in rodent brain was investigated. 3H‐nicotine and 3H‐acetylcholine (3H‐ACh) were used as receptor ligands. Specific binding sites for 3H‐nicotine and 3H‐ACh were detected in mouse brain during the late prenatal period. A drop in the number of 3H‐nicotine and 3H‐ACh binding sites was measured shortly after birth. The 3H‐nicotine and 3H‐ACh binding sites showed different time courses during prenatal development. Competition experiments using unlabelled (−)nicotine and3H‐nicotine revealed one population of high affinity nicotinic binding sites in the cortex of 1‐day and 5‐day‐old mice whereas both a set of high and low affinity binding sites were found in adult mice. The proportion of cortical high and low affinity nicotinic binding sites did not change with aging although the absolute amount of high affinity nicotinic binding sites decreased. The 3H‐nicotine binding showed different temperature dependence in rat brain of different ages. The results illustrate dynamic changes in nicotinic receptor properties during life span of rodents.
Influence of early chronic phenobarbital treatment on cerebral arteriovenous differences of glucose and ketone bodies in the developing rat
Authors: Schroeder Henri , Bomont Laurent , Nehlig Astrid 
Published: April 2003

AbstractThe influence of an early chronic phenobarbital treatment on cerebral arteriovenous differences of glucose, lactate, pyruvate, β‐hydroxybutyrate and acetoacetate was studied in suckling rats. The animals were treated from day 2 to 21 after birth by a daily injection of 50 mg/kg phenobarbital or by saline and were studied at 10, 14 and 21 days. Phenobarbital treatment induced a decrease in cerebral arteriovenous difference of glucose at P14 and no change at P10 and P21. The barbiturate did not have any influence on cerebral arteriovenous difference of lactate and pyruvate at the three stages studied. Cerebral uptake of β‐hydroxybutyrate was unchanged at P10 and increased by two‐fold at P14 and by threefold at P21 by phenobarbital. Cerebral arteriovenous difference of acetoacetate was low and did not change with the pharmacological treatment. At P14 and P21, the calculated amount of oxygen used by the brain for the oxidation of ketone bodies was twice as high in barbiturate‐ as in saline‐treated rats and reached values of 47 and 16% respectively in phenobarbital‐exposed animals. In addition, the barbiturate seemed to affect the carrier process of β‐hydroxybutyrate from blood to brain. The results of the present study are in good agreement with previous data from our laboratory showing that an early chronic phenobarbital treatment is able to induce a shift in the cerebral energy metabolism balance in favor of ketone bodies.
Connections of the insular cortex in kittens: An anatomical demonstration with wheatgerm agglutinin conjugated to horseradish peroxidase technique
Authors: Shimizu Hideaki , Norita Masao 
Published: April 2003

AbstractThe postnatal development of the afferent and efferent connections of the feline insular cortex was investigated using wheat germ agglutinin conjugated to horseradish peroxidase method. The overall pattern of connections was found to be substantially the same as that observed in adults. In the cortex, anterograde and retrograde labeling was found in the presylvian sulcus, cingulate gyms, cruciate sulcus, medial prefrontal area, lateral suprasylvian cortex, and posterior rhinal sulcus. Subcortical regions containing label included the lateralis medialis‐suprageniculate nuclear complex, ventral medial thalamic nucleus, claustrum, lateral amygdaloid nucleus, hypothalamus, and raphe nuclei. In addition, axonal labeling was seen in the striatum, superior colliculus, and pontine nuclei.In contrast, the insular associational projections in kittens differed markedly from those found in adults. In the early postnatal period (1–14 days), dense terminal labeling was found in the cortical layers I, V and VI as well as in the underlying white matter, whereas only moderate to sparse labeling was observed in layers II, III and IV. By four‐weeks, an adult‐like distribution of terminals was present in each cortical areas: labeling was found mainly in layers I, II, III and IV, with less in layers V and VI.The present results suggest that the basic framework of the insular connections is formed prenatally and that the fine tuning of the axonal terminals and the formation of synapses occurs mainly during the first four postnatal weeks.
Effect of acetyl‐L‐carnitine on forebrain cholinergic neurons of developing rats
Authors: De Simone R. , Ramacci M.T. , Aloe L. 
Published: April 2003

AbstractIt has been shown that the endogenous compound, acetyl‐L‐carnitine (ALCAR), acts in the brain as a metabolic cofactor in the synthesis of acetylcholine. In these studies, ALCAR was injected into the brain of developing rats every other day for the first three weeks after birth in order to assess its effect on forebrain cholinergic neurons. The results showed that intracerebroventricular (icv) administration of ALCAR causes an increase of choline acetyltransferase (ChAT) activity and of nerve growth factor receptor expression in the striatum. Biological assays of brain tissues revealed that the level of nerve growth factor (NGF) in the hippocampus also increases. The ability of brain cholinergic tissues to respond to exogenous administration of ALCAR is discussed.
Insulin receptor in mouse neuroblastoma cell line N18TG2: Binding properties and visualization with colloidal gold
Authors: Sartori C. , Stefanini S. , Bernardo A. , Augusti‐Tocco G. 
Published: April 2003

AbstractInsulin function in the nervous system is still poorly understood. Possible roles as a neuromodulator and as a growth factor have been proposed (Baskin et al., 1987, Ann. Rev. Physiol. 49, 335–347). Stable cell lines may provide an appropriate experimental system for the analysis of insulin action on the various cellular components of the central nervous system.We report here a study to investigate the presence and the properties of insulin specific binding sites in the murine neuroblastoma line, N18TG2, together with insulin action on cell growth and metabolism. Also, receptor internalization has been studied. Binding experiments, carried out in standard conditions at 20°C, enabled us to demonstrate that these cells bind insulin in a specific manner, thus confirming previous findings on other cell lines. Saturation curves showed the presence of two binding sites with Kd 0.3 and 9.7 nM. Competition experiments with porcine and bovine insulin showed an IC50 of 1 and 10 nM, respectively. Competition did not occur in the presence of the unrelated hormones ACTH and FSH. Dissociation experiments indicated the existence of an internalization process of the ligandreceptor complex; this was confirmed by an ultrastructural study using gold conjugated insulin. As far as the insulin action in N18TG2 cells is concerned, physiological concentrations stimulate cell proliferation, whereas no stimulation of glucose uptake was observed, indicating that insulin action in these cells is not mediated by general metabolic effects.On the basis of these data, N18TG2 line appears to be a very suitable model for further studies of the neuronal type insulin receptors, and possibly insulin specific action on the nervous system.
Culture of dorsal root ganglion neurons from aged rats: Effects of acetyl‐l‐carnitine and NGF
Authors: Manfridi A. , Forloni G.L. , Arrigoni‐Martelli E. , Mancia M. 
Published: April 2003

AbstractIn vitro neuronal preparations are used to study the action mechanism of substances which are active in normal and pathological brain aging. One major concern with in vitro assays is that the use of embryonic or adult neurons may hamper an appreciation of the relevance of these substances on aged nervous tissue. In the present study for the first time cultures of aged dorsal root ganglia from 24‐months‐old rats were maintained in vitro up to 2 weeks. This model was used to investigate the neurotrophic/ neuroprotective action of nerve growth factor and acetyl‐l‐carnitine. A large population of aged dorsal root ganglia neurons was responsive to nerve growth factor (100 ng/ml). Nerve growth factor induced an increase of initial rate of axonal regeneration and influenced the survival time of these neurons. Acetyl‐l‐carnitine (250 μM) did not affect the axonal regeneration but substantially attenuated the rate of neuronal mortality. A significant difference was evident between the acetyl‐l‐carnitine‐treated and the untreated neurons from the first cell counting (day 3 in culture). After 2 weeks the number of aged neurons treated with acetyl‐l‐carnitine was almost double that of the controls. The effects of acetyl‐l‐carnitine on aged DRG neurons potentially explain the positive effects in clinical and in vivo experimental studies.
The onset of dopaminergic innervation during ontogeny decreases melanotrope proliferation in the intermediate lobe of the rat pituitary
Authors: Gary Keith A. , Chronwall Bibie M. 
Published: April 2003

AbstractThe onset of dopaminergic innervation and its effects on melanotrope proliferation were investigated in the rat pituitary intermediate lobe. Dopamine, and its synthetic rate‐limiting enzyme tyrosine hydroxylase, were first detected immunohistochemically on late post‐natal day 3 or early postnatal day 4. Axon density was highest at the neural lobe/intermediate lobe border, and decreased toward the pituitary cleft. By post‐natal day 10, the adult pattern of tyrosine hydroxylase immunoreactivity was established and remained through post‐natal day 14. Neurointermediate lobe dopamine levels, measured by HPLC, correlated well with the increased axon density observed in the immunohistochemical studies. Dopamine could not be measured by our assay (100 fg limit) until post‐natal day 3 (439.32 fg/NIL). Dopamine concentration increased to 2.09 ± 0.425 ng at PN 4, 86.31 ± 20.42 ng at PN 7, 168.72 ± 18.37 ng at PN 10. Melanotrope proliferation was determined by [3H]thymidine incorporation before and after innervation. Concomitant with the onset of innervation, the proliferation index dropped from 13.4 ± 0.01% to 6.5 ± 0.002% at PN 4, and continued to decrease until a level of 3 ± 0.003% was established by PN 10. To confirm the inhibitory action of dopaminergic innervation on melanotrope proliferation, rat neonates were injected intracisternally with 150 mg 6‐hydroxydopamine to destroy dopaminergic axons within the intermediate lobe. Measurement of dopamine concentrations in neurointermediate lobes of injected animals showed a decrease in dopamine levels as compared to controls. From PN 4 (0.88 ± 0.165 ng), DA levels gradually increased during development: at PN 5, [DA] = 0.689 ± 0.104 ng; PN 6 [DA] = 11.60 ± 2.24 ng; PN 7 [DA] = 20.93 + 3.80 ng; and PN 10 [DA] = 27.95 ± 3.46 ng. Melanotrope proliferation also increased in 6‐hydroxydopamine‐treated animals. At PN 4, the onset of innervation reduced the pre‐innervation proliferation index to 8.75 ± 0.002%, only a 30% reduction in contrast to the > 50% decrease observed in control animals. A stable proliferation level of approximately 7.5% persisted in all subsequent stages with 6‐OHDA administration.Our results demonstrated the time of dopamine innervation onset and a characteristic developmental pattern for axons within the rat intermediate lobe. The onset of innervation and increased dopamine concentration suggests increased dopaminergic control of the melanotropes, illustrated specifically by a decrease in their level of proliferation. This is the first presentation of evidence showing that dopaminergic innervation within the intermediate lobe of the rat pituitary regulates melanotrope proliferation.
Trophic influences of human and rat amniotic fluid on neural tube‐derived rat fetal cells
Authors: Colombo Jorge A. , Napp Mónica , Depaoli Juan R. , Puissant Virginia 
Published: April 2003

AbstractNormal human (week 17–20) and rat (E16–17) amniotic fluids were used as culture media for primary cultures of rat fetal (E 16) cortical, mesencephalic and striatal cell dissociates, or astroglial subcultures from the same brain regions. Phase‐bright and dark cells were identified under phase contrast microscopy and their cell processes were measured utilizing semi‐automated procedures. Subcultured astroglia were immuno‐reacted against glial fibrillary acidic protein and fibronectin. Rat and human amniotic fluid allowed survival and growth of neuronal and non‐neuronal cells. Human amniotic fluid samples were trophic in variable degrees. Cerebral cortex subcultured astroglia usually expressed a radial‐like morphotype. Although charcoal‐adsorbed human amniotic fluid was trophic for primary cultures, its ability to sustain neuritic growth depended on its degree of trophism before treatment. Growth of cell processes in neuronal‐ and glial‐like cells in primary cultures was inhibited to different degrees by the addition of antisera towards nerve or epidermal growth factors. It is concluded that amniotic fluid constitutes a trophic medium for astroglia and neurons. Both, nerve and epidermal growth factors appear to be necessary for growth of cell processes in neuronal and glial primary cultures in amniotic fluid. Trophic effect of amniotic fluid on subcultured astroglia did not seem to be diminished by nerve growth factor antiserum. The role of amniotic fluid during the early phases of brain organogenesis is discussed.