bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcripts for secreted and GPI‐anchored brevican are differentially distributed in rat brain
Authors: Seidenbecher Constanze I. , Gundelfinger Eckart D. , Böckers Tobias M. , Trotter Jacqueline , Kreutz Michael R. 
Published: March 2003

AbstractBrevican is a member of the aggrecan/versican family of proteoglycans. In contrast to the other family members, brevican occurs both as soluble isoforms secreted into the extracellular space and membrane‐bound isoforms which are anchored to the cell surface via a glycosylphosphatidylinositol (GPI) moiety. Expression of both variants, which are encoded by two differentially processed transcripts from the same gene, is confined to the nervous system. In the current study, we have used in situ hybridization to examine the cellular sites of synthesis for both mRNAs during postnatal development of the rat brain. Whereas the 3.6‐kb transcript encoding secreted brevican displays a widespread distribution in grey matter structures, including cerebellar and cerebral cortex, hippocampus and thalamic nuclei with silver grains accumulating over neuronal cell bodies, the smaller transcript (3.3 kb) encoding GPI‐anchored isoforms appears to be largely confined to white matter tracts and diffusely distributed glial cells. This expression pattern is further confirmed by reverse transcriptase‐polymerase chain reaction (RT‐PCR) experiments with RNA from different glial cell cultures, and by biochemical data demonstrating that the crude membrane fraction from isolated optic nerve contains high amounts of phosphatidylinositol‐specific phospholipase C (PI‐PLC)‐sensitive brevican immunoreactivity. During ontogenetic development, both brevican transcripts are generally up‐regulated. However, the expression of glypiated brevican is delayed by about 1 week, compared with the expression of the secreted isoform. This late appearance of GPI‐linked brevican, its predominant expression in glial cells and its tight association with brain myelin fractions suggest a functional role in neuroglia.
No‐go dominant brain activity in human inferior prefrontal cortex revealed by functional magnetic resonance imaging
Authors: Konishi Seiki , Nakajima Kyoichi , Uchida Idai , Sekihara Kensuke , Miyashita Yasushi 
Published: March 2003

AbstractWe investigated the response inhibition function of the prefrontal cortex associated with the go/no‐go task using functional magnetic resonance imaging in five human subjects. The go/no‐go task consisted of go and no‐go trials given randomly with roughly equal probability. In go trials a green square was presented and the subjects had to respond by promptly pushing a button using their right or left thumbs, but in no‐go trials a red square was presented and subjects were instructed not to respond. When brain activity in no‐go trials is dominant over that in go trials in areas in the prefrontal cortex, this no‐go dominant brain activity would reflect the neural processes for inhibiting inherent response tendency. We used a new strategy of image data analysis by which transient brain activity in go or no‐go trials can be analysed separately, and looked for the prefrontal areas in which the brain activity in no‐go trials is dominant over that in go trials. We found the no‐go dominant foci in the posterior part of the right inferior frontal sulcus reproducibly among the subjects. This was true whether the right or left hand was used. These results suggest that this region in the prefrontal cortex is related to the neural mechanisms underlying the response inhibition function.
Microglial NO induces delayed neuronal death following acute injury in the striatum
Authors: Takeuchi Akihide , Isobe Ken‐ichi , Miyaishi Osamu , Sawada Makoto , Fan Zou‐Heng , Nakashima Izumi , Kiuchi Kazutoshi 
Published: March 2003

AbstractWe have established a novel injury model in the central nervous system by a stereotaxic injection of ethanol into rat striatum to induce necrosis. With this model, we clarify a function of inducible nitric oxide synthase (iNOS) in a healing mechanism around a necrotic lesion. A semiquantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) revealed that the iNOS mRNA arose at 6 h, peaked at 24 h, and declined to a lower level 48 h after an intrastriatal 5‐μL ethanol injection. From in situ hybridization, this iNOS mRNA was expressed in the area surrounding the injury. By immunohistochemistry, mononuclear cells at this boundary area of necrosis were stained with anti‐iNOS antibody on the first day after the injury. These cells turned out to be reactive microglia from the positive staining of GSA‐I‐B4, ED‐1 and OX‐42. Haematoxylin‐eosin (HE) staining showed that neurons in this boundary area gradually disappear up to 5 days after the injury with an increment of microglial cells, and this area became cavernous. Nuclei of neurons in this area were stained positive by the terminal deoxynucleotidyl‐transferase‐mediated dUTP‐biotin nick end‐labelling (TUNEL) assay on the first day after the injury. These TUNEL‐positive neurons gradually disappeared toward the third day, while microglial cells increased. L‐Ng‐nitro‐arginine methylester (L‐NAME), a competitive NOS inhibitor, administration diminished the elimination of neurons by microglia in this boundary area surrounding necrosis. Microglial NO may act as a neurotoxic agent to eliminate damaged neurons near the necrosis in the form of delayed neuronal death, and may reintegrate the neuronal circuits with functionally intact neurons.
Developmental changes in localization of NMDA receptor subunits in primary cultures of cortical neurons
Authors: Li Jin Hong , Wang Yue Hua , Wolfe Barry B. , Krueger Karl. E. , Corsi Lorenzo , Stocca Gabriella , Vicini Stefano 
Published: March 2003

AbstractImmunoblot analysis, using antibodies against distinct N‐methyl‐d‐aspartic acid (NMDA) receptor subunits, illustrated that the NR2A and NR2B subunit proteins have developmental profiles in cultured cortical neurons similar to those seen in vivo. NR1 and NR2B subunits display high levels of expression within the first week. In contrast, the NR2A subunit is barely detectable at 7 days in vitro (DIV) and then gradually increased to mature levels at DIV21. Immunocytochemical analysis indicated that NMDA receptor subunits cluster in the dendrites and soma of cortical neurons. Clusters of NR1 and NR2B subunits were observed as early as DIV3, while NR2A clusters were rarely observed before DIV10. At DIV18, NR2B clusters partially co‐localize with those of NR2A subunits, but NR2B clusters always co‐localize with those of NR1 subunits. Synapse formation, as indicated by the presence of presynaptic synaptophysin staining, was observed as early as 48–72 h after plating. However, in several neurons at ages less than DIV5 where synapses were scarce, NR2B and NR1 clusters were abundant. Furthermore, while NR2B subunit clusters were seen both at synaptic and extrasynaptic sites, NR2A clusters occurred almost exclusively in front of synaptophysin‐labelled boutons. This result was supported by electrophysiological recording of NMDA‐mediated synaptic activity [NMDA‐excitatory postsynaptic currents (EPSCs)] in developing neurons. At DIV6, but not at DIV12, CP101, 606, a NR1/NR2B receptor antagonist, antagonized spontaneously occurring NMDA‐EPSCs. Our data indicate that excitatory synapse formation occurs when NMDA receptors comprise NR1 and NR2B subunits, and that NR2A subunits cluster preferentially at synaptic sites.
G‐proteins and G‐protein subunits mediating cholinergic inhibition of N‐type calcium currents in sympathetic neurons
Authors: Delmas Patrick , Abogadie Fe C. , Dayrell Mariza , Haley Jane E. , Milligan Graeme , Caulfield Malcolm P. , Brown David A. , Buckley Noel J. 
Published: March 2003

AbstractOne postsynaptic action of the transmitter acetylcholine in sympathetic ganglia is to inhibit somatic N‐type Ca2+currents: this reduces Ca2+‐activated K+currents and facilitates high‐frequency spiking. Previous experiments on rat superior cervical ganglion neurons have revealed two distinct pathways for this inhibitory action: a rapid, voltage‐dependent inhibition through activation of M4muscarinic acetylcholine receptors (mAChRs), and a slower, voltage‐independent inhibition via M1mAChRs (Hille (1994)Trends in Neurosci.,17,531–536]. We have analysed the mechanistic basis for this divergence at the level of the individual G‐proteins and their α and βγ subunits, using a combination of site‐directed antibody injection, plasmid‐driven antisense RNA expression, over‐expression of selected constitutively active subunits, and antagonism of endogenously liberated βγ subunits by over‐expression of βγ‐binding β‐adrenergic receptor kinase 1 (βARK1) peptide. The results indicate that: (i) M4mAChR‐induced inhibition is mediated by GoA;(ii) α and βγ subunits released from the activated GoAheterotrimer produce separate voltage‐insensitive and voltage‐sensitive components of inhibition, respectively; and (iii) voltage‐insensitive M1mAChR‐induced inhibition is likely to be mediated by the α subunit of Gq. Hence, Ca2+current inhibition results from the concerted, but independent actions of three different G‐protein subunits.
Glutamate receptor subunits GluR1 and GluR2/3 distribution shows reorganization in the human epileptogenic hippocampus
Authors: De Lanerolle Nihal C. , Eid Tore , Von Campe Gord , Kovacs Ilona , Spencer Dennis D. , Brines Michael 
Published: March 2003

AbstractThe AMPA‐type glutamate receptor subunits GluR1 and GluR2/3 were localized by immunohistochemistry with subunit‐specific antibodies in hippocampi removed surgically from patients with temporal lobe epilepsy for the control of seizures. The flip and flop splice variants of the subunits were localized by in situ hybridization histochemistry with specific oligoprobes. In patient hippocampi that were not the seizure focus, the GluR1 subunit proteins were diffusely expressed on the dendrites of neurons in all regions. In contrast, in these same hippocampi, the GluR2/3 subunit proteins were expressed strongly on the soma and proximal dendrites of principal neurons in all regions. The flip variant of these subunits was localized in the hilus and fields of Ammon's Horn (CA), while the flop variants were prominent on the dentate granule cells. In the epileptogenic hippocampus, while immunoreactivity was decreased in all fields that showed neuronal loss, there was an increased expression of GluR1 on the dendritic excrescences on the proximal dendrites of hilar neurons and CA3 pyramidal neurons, as well as expression of GluR2/3 in hilar neuron excrescences. Electron microscopic examination confirmed that the GluR1 immunoreactivity was only in dendritic processes, particularly dense at the postsynaptic membranes. Such expression of GluR1 may provide for an enhanced glutamatergic response by these neurons. GluR2/3 was also significantly increased on the dendrites of dentate granule cells in the epileptogenic hippocampus and may provide some protection against excitotoxic injury by reducing calcium flux into neurons.
Vasoactive intestinal peptide shortens both G1 and S phases of neural cell cycle in whole postimplantation cultured mouse embryos
Authors: Gressens Pierre , Paindaveine Bénédicte , Hill Joanna M. , Evrard Philippe , Brenneman Douglas E. 
Published: March 2003

AbstractVasoactive intestinal peptide, a trophic and mitogenic factor, stimulates growth in whole cultured mouse embryos. Inhibition of this growth function between embryonic days 9 and 11 induces growth retardation accompanied by severe microcephaly. In the present study, to determine the effects of this peptide on the different phases of the cell cycle of neural cells, embryonic day 9.5 cultured mouse embryos were cumulatively labelled with bromodeoxyuridine. Vasoactive intestinal peptide (10–7m) shortened S phase and G1 phase of neuroepithelial cells by 50% (4.8–2.4 h) and 58% (1.9–0.8 h), respectively, compared with controls. G2 and M phases were not modified by vasoactive intestinal peptide treatment. Total cell cycle length was consequently reduced by 43% (8.2–4.7 h) in vasoactive intestinal peptide treated embryos, compared with controls. In contrast, vasoactive intestinal peptide did not modify the rate of neuroepithelial cell death as assessed by the proportion of nuclei containing fragmented DNA. These data suggest that vasoactive intestinal peptide stimulates growth in premigratory stages of nervous system development by shortening S and G1 phases of the cell cycle and that S phase duration can be regulated by a physiological peptide.
Coexpression of dopamine D1and D3receptors in islands of Calleja and shell of nucleus accumbens of the rat: opposite and synergistic functional interactions
Authors: Ridray Sophie , Griffon Nathalie , Mignon Virginie , Souil Evelyne , Carboni Suzanna , Diaz Jorge , Schwartz Jean‐Charles , Sokoloff Pierre 
Published: March 2003

AbstractUsing doublein situhybridization, we found extensive coexpression of dopamine D1and D3receptor (D1R and D3R) mRNAs in neurons of the island of Calleja major (ICjM) and ventromedial shell of nucleus accumbens (ShV), respectively. Thus, at least 79 and 63% of D3R mRNA‐expressing neurons in ICjM and ShV also expressed the D1R mRNA. Coexpression of D1R and D3R mRNAs was found to occur in substance P (SP) mRNA‐expressing neurons in both areas, suggesting SP mRNA as a marker of the activity of coexpressing neurons. Administration of SKF 38393, a D1R receptor agonist, increased c‐fos mRNA in ICjM, whereas administration of quinpirole, a D2R/D3R agonist, decreased it; SCH 23390, a D1R antagonist and nafadotride, a preferential D3R antagonist, given alone, had effects opposite to those of the corresponding agonists. These data indicate that basal c‐fos expression in ICjM is maintained by endogenous dopamine acting tonically upon two receptor subtypes subserving opposite effects on the same cell. However, in ShV, whereas SKF 38393 also increased c‐fosmRNA, quinpirole had no effect, a difference presumably reflecting the lower fraction of neurons coexpressing D1R and D3R in this area. In contrast, in ShV from reserpine‐treated rats, SKF 38393 increased SP mRNA and quinpirole potentiated this effect. These contrasting interactions of D1R‐ and D3R‐mediated signalling events, i.e. in either opposite or synergistic directions, most likely occurring at the single cell level, may serve to increase the dopamine response threshold of the target cells in ICjM and to maintain a strong tonic activity of ShV neurons.
Differential regulation of FAK+ and PYK2/Cakβ, two related tyrosine kinases, in rat hippocampal slices: effects of LPA, carbachol, depolarization and hyperosmolarity
Authors: Derkinderen Pascal , Siciliano Julio , Toutant Madeleine , Girault Jean‐Antoine 
Published: March 2003

AbstractFAK+, an isoform of focal adhesion kinase preferentially expressed in brain and PYK2/Cakβ (proline‐rich tyrosine kinase 2/cell adhesion kinaseβ) are two related cytoplasmic tyrosine kinases. They are candidates for coupling electrical activity and stimulation of neurotransmitter receptors to short and long‐term changes in synaptic properties, cytoskeletal organization and gene expression in neurons. As the same set of stimuli appear capable of stimulating FAK and/or PYK2 in non‐neuronal cells and in cell lines with neuronal characteristics, we investigated the selectivity of regulation of these two kinases in mature nervous tissue. Using rat hippocampal slices, we compared the regulation of FAK+ and PYK2 by stimuli known to be active on one or the other of these two kinases in other cell types: lysophosphatidic acid (LPA), carbachol, depolarization, and hyperosmolarity. Phosphorylation of FAK+ was markedly increased by carbachol and LPA. Carbachol effects occurred via activation of M1 muscarinic receptors and nicotinic receptors. The effects of carbachol and LPA were prevented by protein kinase C inhibitors, whereas 8‐Br‐cAMP attenuated the effects of carbachol but not of LPA. Tyrosine phosphorylation of PYK2 but not of FAK+ was very strongly enhanced by depolarization and hyperosmolarity. This study and our previous results show that FAK+ and PYK2 are regulated differentially in hippocampal slices: FAK+ is phosphorylated on tyrosine in response to stimulation of G protein‐coupled receptors, whereas PYK2 is mainly sensitive to depolarization and hyperosmolarity. Thus, FAK+ and PYK2 may provide specific and separate links between activation of neurotransmitters receptors, depolarization and tyrosine phosphorylation in mature hippocampus.
Δ9‐Tetrahydrocannabinol increases sequence‐specific AP‐1 DNA‐binding activity and Fos‐related antigens in the rat brain
Authors: Porcella Anna , Gessa Gian Luigi , Pani Luca 
Published: March 2003

AbstractDelta‐9‐tetrahydrocannabinol (Δ9‐THC), the psychoactive principle of marijuana, has been shown to upregulate the mRNA levels of immediate‐early genes in the rat brain. Using electrophoretic mobility‐shift assay and one‐dimensional Western blot, we here report that Δ9‐THC increases Activator protein‐1 (AP‐1) DNA‐binding and Fos‐related antigen activity in discrete areas of the rat brain. One hour after the intraperitoneal administration of Δ9‐THC at a dose of 10 or 15 mg/kg, AP‐1 DNA‐binding activity in the nucleus accumbens increased by 33 and 49%, respectively, while Western blot showed an increase in both c‐Fos, FosB, Fra‐1 (Fos‐related antigen) and Fra‐2. In the cingulate cortex and caudate‐putamen, Δ9‐THC significantly increased AP‐1 DNA‐binding activity only at the highest dose used (57 and 71%, respectively). While in the caudate‐putamen the increase in AP‐1 DNA binding was mainly due to an elevation of the c‐Fos and FosB proteins, the same phenomenon depended on the FosB, Fra‐1 and Fra‐2 peptides in the cingulate cortex. The effect of Δ9‐THC on the AP‐1 DNA binding and the Fos‐related antigens in the nucleus accumbens was blocked by the specific cannabinoid antagonist SR141716 A (3 mg/kg i.p.). Δ9‐THC failed to modify Specificity protein 1 (Sp1) DNA‐binding activity. The results indicate that Δ9‐THC activates gene coding for AP‐1 DNA‐binding proteins by acting on cannabinoid receptors, and induces a different transcriptional program on the early‐immediate gene of the Fos family, in different areas in the rat brain, suggesting that this mechanism might be involved in the central actions of cannabinoids.
Evidence for a striatal NMDA receptor modulation of nigral glutamate release. A dual probe microdialysis study in the awake freely moving rat
Authors: Morari Michele , Sbrenna Simone , Marti Matteo , O'Connor William T. , Bianchi Clementina , Fuxe Kjell , Beani Lorenzo 
Published: March 2003

AbstractDual probe microdialysis was employed to characterize dialysate glutamate levels from the substantia nigra pars reticulata of awake freely moving rats, and to test its sensitivity to alterations in striatal neurotransmission including striatal N‐methyl‐d‐aspartic acid (NMDA) receptor stimulation and blockade. Intranigral perfusion with low (0.1 mm) Ca2+ medium (60 min) did not affect nigral glutamate levels, whereas intranigral perfusion with tetrodotoxin (10 μm, 60 min) increased nigral glutamate levels. Perfusion of KCl (100 mm, 10 min) in the dorsolateral striatum transiently stimulated nigral glutamate levels (maximal increase + 60%), whereas intrastriatal perfusion (60 min) with low Ca2+ medium and tetrodotoxin gradually increased nigral glutamate levels. Intrastriatal perfusion with NMDA (0.1–100 μm, 10 min) dose‐dependently stimulated glutamate levels in the substantia nigra pars reticulata. The NMDA (1 μm)‐induced increase in nigral glutamate release was transient and maximal (+60% within 20 min), whereas that for NMDA (10 μm) had a slow onset but was long lasting (+35% after 60 min). Lower (0.1 μm) and higher (100 μm) NMDA concentrations were ineffective. The effect of intrastriatal NMDA (1 μm) was prevented by coperfusion with MK‐801 (1 μm). Intrastriatal MK‐801 (10 μm) alone gradually increased glutamate levels up to +50% after 60 min of perfusion. The present results suggest that glutamate levels in the substantia nigra pars reticulata are sensitive to changes in neuronal transmission in the dorsolateral striatum, and that striatal NMDA receptors regulate nigral glutamate release in both a tonic and phasic fashion.
Study of subcellular localization of membrane‐bound choline acetyltransferase in Drosophila central nervous system and its association with membranes
Authors: Pahud Gabrielle , Salem Natalie , Van De Goor Jana , Medilanski Jana , Pellegrinelli Nathalie , Eder‐Colli Lorenza 
Published: March 2003

AbstractCholine acetyltransferase (ChAT), the enzyme which catalyses the biosynthesis of the neurotransmitter acetylcholine, exists in a soluble and membrane‐bound form in cholinergic nerve terminals of different animal species. This study was performed on the enzyme present in Drosophila central nervous system. We show that the two forms of the enzyme have the same apparent molecular weight (75 kDa) when analysed by immunoblotting using an antibody we raised against the recombinant enzyme. According to different authors, membrane‐bound enzyme might be associated with synaptic vesicles or plasma membrane. Subfractionation of Drosophila head homogenates in linear glycerol gradients showed that ChAT does not associate with synaptic vesicles. Analysis of ChAT activity and immunoreactivity showed that two peaks of ChAT were produced. One peak was present in fractions containing soluble components and the other was associated with rapidly sedimenting membranes containing plasma membranes. ChAT in the first peak was mainly hydrophilic. A large proportion of ChAT associated with rapidly sedimenting membranes was amphiphilic. Further fractionation of these membranes by flotation in sucrose gradients showed that membrane‐associated ChAT sedimented in fractions containing plasma membrane marker. Membrane‐bound ChAT was neither solubilized nor converted to hydrophilic enzyme after membrane treatment with 1 m hydroxylamine, suggesting that the enzyme is not palmitoylated and therefore not anchored to membrane through thioester‐linked long chain fatty acid. Partial solubilization of ChAT present on membranes with urea and carbonate suggests that this form of ChAT is a peripheral membrane protein. Carbonate solubilization of membrane‐bound ChAT converted the enzyme from hydrophobic to hydrophilic protein.