bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laminar expression of m1‐, m3‐ and m4‐muscarinic cholinergic receptor genes in the developing rat visual cortex using in situ hybridization histochemistry. Effect of monocular visual deprivation
Authors: Roβner Steffen , Kues Wilfried , Witzemann Veit , Schliebs Reinhard 
Published: April 2003

AbstractThe postnatal development of laminar pattern of m1‐, m3‐ and m4‐mRNA‐muscarinic acetylcholine receptor subtypes in the visual cortex of both normally raised and monocularly deprived rats (one eyelid sutured at the age of 11 days) was studied using in situ hybridization histochemistry and computer‐assisted image analysis. From birth until day 15 the level of m1‐receptor transcript in layer II/III increases markedly as compared to deeper layers. From day 15 up to day 18 a transient bimodal pattern develops with peaks in layers II/III and VI. Already on day 35 a more homogeneous distribution of m1‐receptor mRNA level is detectable persisting until adulthood. In contrast, the m3‐receptor mRNA shows already at birth a bimodal distribution with peaks in layers II/III and VI. Further development until adulthood results in transient changes in the ratio of the mRNA levels in these layers. In the adult visual cortex a similar laminar pattern as at birth is observed. From day 1 up to day 10 a relative increase in the mRNA level of the m4‐receptor in layers II to IV is observed. From day 10 until day 15 a bimodal distribution of receptor mRNA develops with peaks in layers III and VI which is similar to the adult stage. However, between days 18 and 35 a shift in the laminar receptor mRNA distribution occurs resulting in peaks in layers IV and VI. The labeling of the m5‐receptor transcript in rat visual cortex was very weak and did not show any alteration with age.Unilateral eyelid closure from postnatal day 11 resulted in transient changes in the laminar distribution of m3‐ and m4‐receptor mRNA between postnatal days 18 and 25, whereas the development of the laminar pattern of the m1‐receptor mRNA was not affected regardless of the length of visual deprivation.The distinct laminar developmental pattern of mRNA muscarinic receptor subtypes in rat visual cortex suggests specific roles of the muscarinic receptor subtypes during the first weeks of postnatal maturation of visual function.
Effects of early chronic diazepam treatment on incorporation of glucose and β‐hydroxybutyrate into cerebral amino acids: Relation to undernutrition
Authors: Schroeder Henri , Collignon Alain , Uttscheid Laurent , de Vasconcelos Anne Pereira , Nehlig Astrid 
Published: April 2003

AbstractThe effects of early chronic diazepam (DZP) exposure on blood glucose and ketone body concentration and glucose and β‐hydroxybutyrate (βHB) utilization for regional cerebral amino acid biosynthesis were studied in suckling rats. The animals were treated from postnatal day 2 (P2) to 21 (P21) by a daily subcutaneous injection of 10 mg/kg DZP or of the dissolution vehicle and studied at P5, P10, P14 and P21, together with an additional group of food‐restricted rats obtained by an increase in litter size. DZP treatment induced a 9–26% decrease in body and brain weight. Undernutrition decreased body weight by 20–24% at all ages whereas brain weight was relatively spared. DZP and N‐desmethyldiazepam concentrations decreased with age and were cleared from brain and plasma by 6–8 hrs after the injection. DZP decreased plasma glucose concentrations by 6–12% at P5, P14 and P21, whereas undernutrition did not change plasma glucose concentrations, except for a 7% decrease at P14. DZP treatment had no consequences on circulating concentrations of both ketone bodies while undernutrition increased their concentration by 45–362% at all ages. The conversion of [14C]glucose into cerebral amino acids was reduced by DZP at P5 and P10. The cerebral concentration of neurotransmitter amino acids was not affected by DZP treatment which only increased the amount of neutral amino acids mainly in the cerebellum at P5 and P10. After [U‐14C]glucose injection, specific radioactivities of cerebral amino acids were mostly decreased by DZP from P5 to P14 and significantly increased at P21. With [3‐14C]βHB as a precursor, specific radioactivities of neurotransmitter amino acids were increased by DZP. In conclusion, P5 and P10 rats appear to be most sensitive to DZP effects whereas some tolerance to the drug seems to develop by P21. The lack of effects of DZP on blood ketone body concentrations compared to food restriction as well as the relative sparing of brain weight in undernourished rats confirms that the cerebral metabolic consequences of early DZP exposure on brain energy metabolism are mostly direct effects not mediated by sedation‐induced undernutrition.
Biochemical properties of Na+/K+‐ATPase in axonal growth cone particles isolated from fetal rat brain
Authors: Mercado R. , Hernández‐R. J. 
Published: April 2003

AbstractAxonal growth cones (AGC) isolated from fetal rat brain have an important specific activity of N+/K+‐ATPase. Kinetic assays of the enzyme in AGC showed that Km values for ATP or K+ are similar to those reported for the adult brain enzyme. For Na+ the affinity (Km) was lower. Vmax for the three substrates was several times lower in AGC as compared to the adult value. We also observed two apparent inhibition constants of Na+/K+‐ATPase by ouabain, one of low affinity, possibly corresponding to the α1 isoform and another of high affinity which is different to that described for the α2 isoform of the enzyme. These results support an important role for the sodium pump in the mantainance of volume and cationic balance in neuronal differentiating structures. The functional differences observed also suggest that the enzymatic complex of Na+/K+‐ATPase in AGC is in a transitional state towards the adult configuration.
Characterization of sodium‐independent β‐alanine binding to cerebral cortical membranes from 7‐day‐old and adult mice
Authors: Saransaari Pirjo , Oja Simo S. 
Published: April 2003

AbstractThe sodium‐independent binding of β‐alanine to cerebral cortical membranes from adult (3‐ and 12‐month‐old) and developing (7‐day‐old) mice was characterized for the first time. The binding was saturable in each age group, consisting of only one component. The affinity for β‐alanine was highest and the number of available binding sites greatest in young animals. The binding was not affected by strychnine, but inhibited by β‐alanine itself, glycine, l‐alanine and l‐serine, the IC50 values being lower in immature mice. Glycine was shown to be a competitive inhibitor. The binding was also inhibited, albeit only in adults, by N‐methyl‐d‐aspartate receptor antagonists acting at the glycine modulatory site and by some GABAergic substances. It is concluded that even though β‐alanine may possess binding sites of its own, particularly in the immature cerebral cortex, β‐alanine could at least partly bind to strychnine‐insensitive glycine sites in the N‐methyl‐d‐aspartate receptor complex.
Growth factor‐induced neurite growth in primary neuronal cultures of dogs with neuronal ceroid lipofuscinosis
Authors: Dunn William A. , Raizada Mohan K. , Vogt E.Suzanne , Brown Elizabeth A. 
Published: April 2003

AbstractNeuronal ceroid lipofuscinosis (NCL) is a type of lysosomal storage disease resulting in the progressive deterioration of neuronal function. Little is known about the genetics, pathophysiology and biochemical basis of this disease. This is, in part, due to the complexity of the central nervous system and the lack of an in vitro model. In this report, we describe the conditions to establish neuronal cells in primary culture from the brains of newborn English setters with NCL, a canine model for this disease. Over 80% of the neuronal cells from normal dog brain establish well‐developed interconnecting networks of long neurites. On the contrary, approximately 50% of the neurons cultured from NCL dog brains do not assemble neurites. Of those NCL neurons with processes, the neurites are routinely shorter and fewer in number than those seen in normal cultures. In addition, the characteristic inclusion bodies, pathological markers for this disease in vivo, are prevalent in the soma of cultured neuronal cells isolated from NCL dog brain. A time‐dependent maturation of the inclusion bodies suggests a progression of the disease state in culture. The reduced ability of the NCL neurons to establish neurites prompted us to examine the effects of growth factors on neurite assembly. Our data show that insulin‐like growth factor I, epidermal growth factor and platelet‐derived growth factor are capable of stimulating neurite outgrowth of NCL neurons.We report the establishment and morphological characterization of neuronal cultures from normal and NCL dog brains. The abnormal morphology of cultured NCL neurons can, in part, be alleviated by supplementing the medium with growth factors. The results suggest that this cellular model of NCL will be useful to study the molecular and physiological mechanisms of NCL disease, as well as to test potential therapeutic agents and candidate genes.
Expression of amyloid precursor protein (APP) in rat brain and cultured neural cells
Authors: Gegelashvili Georgi , Schousboe Arne , Linnemann Dorte 
Published: April 2003

AbstractCell type‐specific and developmental patterns of APP expression were investigated in rat brain and cultured neural cells. Nearly all astrocytes were APP‐positive, whereas only selected population of neurons appeared to express APP. In these neurons, APP immunoreactivity was preferentially restricted to single processes. mRNAs encoding the major APP isoforms, APP695 and APP770, were co‐expressed as 3.4–3.6 kb transcripts both in astrocytes and neurons. In addition, an unusual 2.8 kb mRNA size class was revealed in cultured cerebellar granule neurons by means of the probe recognizing APP770 mRNA. Also, for the first time, APP714 mRNA was detected in rat brain by northern blotting. The steady‐state levels of these transcripts were increased from birth up to postnatal day 20, whereas no apparent changes were observed after reaching adulthood. These data hint at the involvement of APP in the major morphogenetic events taking place in rat brain during the first three postnatal weeks.
Brain‐derived neurotrophic factor and neurotrophin‐4 increase neurotrophin‐3 expression in the rat hippocampus
Authors: Lindholm Dan , da Penha Berzaghi Maria , Cooper Jonathan , Thoenen Hans , Castrén Eero 
Published: April 2003

AbstractHippocampal levels of mRNA encoding nerve growth factor (NGF) and brain‐derived neurotrophic factor (BDNF) are rapidly induced by enhanced neuronal activity following seizures and glutamate or muscarinic receptor activation. However, the levels of neurotrophin‐3 (NT‐3) mRNA acutely decrease after limbic seizures suggesting that a different mode of regulation may exist for these neurotrophins. Here we show that BDNF and neurotrophin‐4 (NT‐4), but not NT‐3 itself, up‐regulate NT‐3 mRNA in cultured hippocampal neurons. In the rat hippocampus, the muscarinic receptor agonist, pilocarpine increased BDNF mRNA levels rapidly and those of NT‐3 with a delay of several hours. Injection of BDNF into neonatal rats elevated NT‐3 mRNA in the hippocampus which demonstrates that BDNF is able to enhance NT‐3 expression in vivo. The regulation of NT‐3 by BDNF and NT‐4 enlargens the neurotrophic spectrum of these neurotrophins to include neuron populations responsive primarily to NT‐3.
Growth of trigeminal neurites and interactions with corneal cells in embryonic chick organ cultures
Authors: Pavlidis Christos , Steuhl Klaus‐Peter , Thanos Solon 
Published: April 2003

AbstractThe investigation of interactions between growing neurites and target cells during the development of the sensible corneal innervation is of crucial importance for understanding certain corneal diseases which are related to abnormal patterns of innervation. The purpose of the present work was to establish a culture system of cornea and trigeminal neurons and to examine interactions between these tissues. The responses of neurons derived from explanted embryonic chick trigeminal ganglia to co‐explanted slices prepared from embryonic cornea were monitored over several days in culture. The growth of trigeminal fibers, but not of neurites derived from control tissues such as trigeminal mesencephalic nucleus or ciliary ganglion, was preferentially directed towards the co‐cultured corneal slices. The ingrowth of trigeminal axons into the cornea was followed by formation of elaborate axonal terminal branches. Individual dissociated trigeminal neurons of pseudo‐unipolar or bipolar classes developed their typical morphologies in culture. In co‐cultures with corneal slices, they reacted to the corneal co‐explant by frequently retracting some branches and forming or elongating other ones, which were predominantly directed towards the target tissue. In addition, the presence of a co‐explanted trigeminal ganglion increased the rate of growth in the dissociated trigeminal neurons. The effect was not additive when cornea was present. Antibodies against nerve growth factor (NGF) and the low‐affinity p75‐NGF receptor (LANGFR) revealed that trigeminal ganglion cells support neuritic growth by secreting NGF, whereas corneal cells secrete additional factor(s) which act via the LANGFR.
Norepinephrine modulates excitatory amino acid‐induced responses in developing human and adult rat cerebral cortex
Authors: Radisavljevic Zivotije , Cepeda Carlos , Peacock Warwick , Buchwald Nathaniel A. , Levine Michael S. 
Published: April 2003

AbstractThese experiments were designed to assess the ability of norepinephrine and its β‐receptor agonist, isoproterenol, to modulate responses induced by activation of excitatory amino acid receptors in brain slices obtained from developing human cortex or adult rat cortex. Human cortical slices were obtained from children undergoing surgery for intractable epilepsy (9 months to 10 yr of age). For comparison, slices were also obtained from rats (2–3 months of age). Iontophoretic application of glutamate, N‐methyl‐d‐aspartate or α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) produced excitatory responses consisting of membrane depolarizations accompanied by action potentials. Iontophoretic or bath application of norepinephrine or isoproterenol enhanced responses evoked by glutamate or N‐methyl‐d‐aspartate. Depolarizations occurred with shorter latencies and their amplitudes increased. Action potential frequency was also increased and responses were of longer duration. In contrast, norepinephrine or isoproterenol had no effect on responses induced by AMPA. The enhancement of responses induced by N‐methyl‐d‐aspartate or glutamate was antagonized by the β‐adrenergic receptor antagonist propranolol. Similar findings were obtained from neurons in humans or rats.These results suggest that norepinephrine, possibly via β‐receptors, potentiates responses mediated by glutamate and N‐methyl‐d‐aspartate receptors without affecting those mediated by AMPA receptors. These effects were observed at all ages studied, indicating that the ability of norepinephrine to modulate excitatory neuronal transmission is well developed in human cortex by 9 months of age.
Developmental profiles of ornithine decarboxylase activity in the hippocampus, neocortex and cerebellum: Modulation following lead exposure
Authors: Zawia N.H. , Evers L.B. , Harry G.J. 
Published: April 2003

AbstractOrnithine decarboxylase (ODC) is a growth‐associated enzyme which is critical for cell growth and transformation. ODC activity follows a specific ontogenetic pattern of activity in distinct brain regions according to their developmental stage. Perturbations in the pattern of ODC activity have been associated with brain damage including arrested cerebral growth. Modulations in the pattern of ODC activity were examined in the hippocampus, neocortex and cerebellum of neonatal rats (PND 3, 6, 9, 15) exposed via the dam to 0.2% lead‐acetate (Pb2+ prenatally (gestational day 13 to birth), postnatally (PND 1–15) or perinatally (gestational day 13 to PND 15). Prenatal exposure to Pb2+ perturbed the profile of ODC activity in all three brain regions examined, while postnatal exposure to Pb2+ resulted in prolonged stimulations of ODC activity in the cerebellum. Following prenatal exposure, these effects were manifested as a stimulation of ODC activity in the hippocampus, a repression of activity in the neocortex and a combination of these effects in the cerebellum. Perinatal exposure to Pb2+ transiently modulated the pattern of ODC activity similarly in all three brain regions, in a characteristic manner irrespective of their developmental stage. These Pb2+‐induced modulations of ODC activity suggest that polyamine‐dependent processes may play a significant role in the manifestation of Pb2+‐induced neurotoxicity dependent upon developmental factors at specific exposure periods.
Characterization of the response of growth and differentiation to lipoproteins and agents affecting cholesterol metabolism in murine neuroblastoma cells
Authors: Castellano F. , Bruscalupi G. , Columba S. , Di Croce L. , Trentalance A. , Augusti‐Tocco G. 
Published: April 2003

AbstractTreatment with mevinolin, a competitive inhibitor of HMGCoAR, the key enzyme of isoprenoid metabolism, causes the arrest of proliferation and the differentiation of a neuroblastoma cell line (N18TG2). Mevalonate and high density lipoproteins partially restore growth.Cholesterol synthesis in the presence of mevinolin remains active, because in these cells the key enzyme HMG‐CoA reductase is not completely inhibited by this drug. The fact that cell growth is reduced, while cholesterogenesis remains active, suggests that mevinolin acts by interfering with the synthesis of some unknown compound, other than cholesterol, which is necessary for proliferation.
Gender, anxiety-depressivity and self-image among adolescents
Authors: Kirkcaldy Bruce , Siefen Georg , Furnham Adrian 
Published: April 2003

AbstractTwo groups of non- and “quasi-depressives”—the latter corresponding to high depression scorers—German adolescents were examined to determine the effect of gender and depression in predicting physical ailments, self-image and attitudes towards parents. Quasi-depressive adolescents displayed higher frequencies of physical complaints across all five subscales of the Giessen physical complaints inventory compared to the non-depressive counterparts. Females generally reported more ailments (exhaustion, gastrointestinal, circulatory, and colds) than males. In contrast to males who showed scarce difference between depressives and non-depressives, female depressives exhibited substantially higher gastrointestinal ailments than non-depressive females. Depressives emerged as displaying inferior self-images, lower paternal acceptance, and somewhat higher maternal rejection, compared to non-depressives. Female adolescents displayed lower self-image, lower paternal acceptance (but not maternal rejection/acceptance), lower mathematical competency, and higher linguistic competency, when compared to male adolescents.
Role of histidine interruption in mitigating the pathological effects of long polyglutamine stretches in SCA1: A molecular approach
Authors: Sen Somdutta , Dash Debasis , Pasha Santosh , Brahmachari Samir K. 
Published: April 2003

AbstractPolyglutamine expansions, leading to aggregation, have been implicated in various neurodegenerative disorders. The range of repeats observed in normal individuals in most of these diseases is 19–36, whereas mutant proteins carry 40–81 repeats. In one such disorder, spinocerebellar ataxia (SCA1), it has been reported that certain individuals with expanded polyglutamine repeats in the disease range (Q12HQHQ12HQHQ14/15) but with histidine interruptions were found to be phenotypically normal. To establish the role of histidine, a comparative study of conformational properties of model peptide sequences with (Q12HQHQ12HQHQ12) and without (Q42) interruptions is presented here. Q12HQHQ12HQHQ12 displays greater solubility and lesser aggregation propensity compared to uninterrupted Q42 as well as much shorter Q22. The solvent and temperature‐driven conformational transitions (β structure ↔ random coil → α helix) displayed by these model polyQ stretches is also discussed in the present report. The study strengthens our earlier hypothesis of the importance of histidine interruptions in mitigating the pathogenicity of expanded polyglutamine tract at the SCA1 locus. The relatively lower propensity for aggregation observed in case of histidine interrupted stretches even in the disease range suggests that at a very low concentration, the protein aggregation in normal cells, is possibly not initiated at all or the disease onset is significantly delayed. Our present study also reveals that besides histidine interruption, proline interruption in polyglutamine stretches can lower their aggregation propensity.
Parietal Lobe Contribution to Mental Rotation Demonstrated with rTMS
Authors: Harris Irina M. , Miniussi Carlo 
Published: April 2003

Abstract
A large number of imaging studies have identified a role for the posterior parietal lobe, in particular Brodmann's area 7 and the intraparietal sulcus (IPS), in mental rotation. Here we investigated whether neural activity in the posterior parietal lobe is essential for successful mental rotation performance by observing the effects of interrupting this activity during the execution of a mental rotation task. Repetitive transcranial magnetic stimulation (rTMS) was applied to posterior parietal locations estimated to overlie Brodmann's area 7 in the right and the left hemisphere, or to a posterior midline location (sham condition). In three separate experiments, rTMS (four pulses, 20 Hz) was delivered at these locations either 200–400, 400–600, or 600–800 msec after the onset of a mental rotation trial. Disrupting neural activity in the right parietal lobe interfered with task performance, but only when rTMS was delivered 400 to 600 msec after stimulus onset. Stimulation of the left parietal lobe did not reliably affect mental rotation performance at any of the time points investigated. The time-limited effect of rTMS was replicated in a fourth experiment that directly compared the effects of rTMS applied to the right parietal lobe either 200–400 or 400–600 msec into the mental rotation trial. The results indicate that the right superior posterior parietal lobe plays an essential role in mental rotation, consistent with its involvement in a variety of visuospatial and visuomotor transformations.
The Pleasure of Believing: Toward a naturalistic explanation of religious conversions
Authors: Clément Fabrice 
Published: April 2003

AbstractFrom a cognitive point of view, the adhesion to religious beliefs, especially those involving adult subjects, are quite mysterious. Religious representations entail paradoxical claims that should imply skepticism or cautious doubts in any rational mind. Nevertheless, it is not rare that they prompt an act of total commitment from the converts. The aim of this paper is to propose a naturalist explanation of the conversion phenomenon. The argument relies on the postulated existence of an emotional signal selected by evolution to motivate the child to look for the underlying structure of the world by providing a strong positive feeling when a solution is found. By the use of different examples of historical conversions, the author shows how this emotional mechanism can be triggered in the presence of religious representations, causing in the subjects the feeling that they have discovered a good solution to problems they were confronted with.