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  • 1
    Electronic Resource
    Electronic Resource
    Striatal Restricted Adenosine A2 Receptor (RDC8) Is Expressed by Enkephalin but Not by Substance P Neurons: An In Situ Hybridization Histochemistry Study (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 57 (1991), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: RDC8 has been recently cloned and characterized as an adenosine A2 receptor. This receptor is expressed exclusively by medium-sized neurons of the striatum as demonstrated by in situ hybridization. We have now studied the relationship of this receptor with three major components of the rat caudate-putamen: enkephalin, substance P, and choline acetyltransferase. Our results demonstrate that the adenosine A2 receptor is expressed exclusively by the enkephalinergic striatal subpopulation but not by the substance P-containing or cholinergic neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1991.tb08257.x
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  • 2
    Electronic Resource
    Electronic Resource
    Functional striatal hypodopaminergic activity in mice lacking adenosine A2A receptors (2001)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 78 (2001), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Adenosine and caffeine modulate locomotor activity and striatal gene expression, partially through the activation and blockade of striatal A2A receptors, respectively. The elucidation of the roles of these receptors benefits from the construction of A2A receptor-deficient mice (A2A-R−/−). These mice presented alterations in locomotor behaviour and striatal expression of genes studied so far, which are unexpected regarding the specific expression of A2A receptor by striatopallidal neurones. To clarify the functions of A2A receptors in the striatum and to identify the mechanisms leading to these unexpected modifications, we studied the basal expression of immediate early and constitutive genes as well as dopamine and glutamate neurotransmission in the striatum. Basal zif268 and arc mRNAs expression was reduced in mutant mice by 60–80%, not only in the striatum but also widespread in the cerebral cortex and hippocampus. Striatal expression of substance P and enkephalin mRNAs was reduced by about 50% and 30%, respectively, whereas the expression of GAD67 and GAD65 mRNAs was slightly increased and unaltered, respectively. In vivo microdialysis in the striatum revealed a 45% decrease in the extracellular dopamine concentration and three-fold increase in extracellular glutamate concentration. This was associated with an up-regulation of D1 and D2 dopamine receptors expression but not with changes in ionotropic glutamate receptors. The levels of tyrosine hydroxylase and of striatal and cortical glial glutamate transporters as well as adenosine A1 receptors expression were indistinguishable between A2A-R−/− and wild-type mice. Altogether these results pointed out that the lack of A2A receptors leads to a functional hypodopaminergic state and demonstrated that A2A receptors are necessary to maintain a basal level in immediate early and constitutive genes expression in the striatum and cerebral cortex, possibly via their control of dopamine pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2001.00389.x
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  • 3
    Electronic Resource
    Electronic Resource
    Decrease of zif-268 and c-fos and Increase of c-jun mRNA in the Cat Areas 17, 18 and 19 Following Complete Visual Deafferentation (1995)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 7 (1995), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We used in situ hybridization to investigate the effect of complete visual deafferentation on immediate early gene expression in adult cat visual cortex. Deafferentation was obtained by unilateral section of the optic tract and sections of both the corpus callosum and anterior commissure. In this model, one hemisphere served as control for the other within the same animal. A decrease in zinc finger protein (zif)-268 and c-fos mRNA was observed in the superficial and deep layers of areas 17 and 18, and all layers of area 19 in the deafferented hemisphere. This decrease, present 3 days after surgery, was maximal after 30 days. An increase of c-jun mRNA was observed in the deep layers of areas 17, 18 and 19 in the deafferented hemisphere 3, 10 and 30 days after surgery. These results suggest that visual input activates zif-268 and c-fos expression and tonically depresses c-jun expression in the primary visual complex yielding similar levels of c-jun and c-fos expression in normal conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1995.tb01119.x
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  • 4
    Electronic Resource
    Electronic Resource
    Bidirectional synaptic plasticity as a consequence of interdependent Ca2+-controlled phosphorylation and dephosphorylation pathways (2003)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 17 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Postsynaptic Ca2+ signals of different amplitudes and durations are able to induce either long-lasting potentiation (LPT) or depression (LTD). The bidirectional character of synaptic plasticity may result at least in part from an increased or decreased responsiveness of the glutamatergic α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPA-R) due to the modification of conductance and/or channel number, and controlled by the balance between the activities of phosphorylation and dephosphorylation pathways. AMPA-R depression can be induced by a long-lived Ca2+ signal of moderate amplitude favouring the activation of the dephosphorylation pathway, whereas a shorter but higher Ca2+ signal would induce AMPA-R potentiation resulting from the preferential activation of the phosphorylation pathway. Within the framework of a model involving calcium/calmodulin-dependent protein kinase II (CaMKII), calcineurin (PP2B) and type 1 protein phosphatase (PP1), we aimed at delineating the conditions allowing a biphasic U-shaped relationship between AMPA-R and Ca2+ signal amplitude, and thus bidirectional plasticity. Our theoretical analysis shows that such a property may be observed if the phosphorylation pathway: (i) displays higher cooperativity in its Ca2+-dependence than the dephosphorylation pathway; (ii) displays a basal Ca2+-independent activity; or (iii) is directly inhibited by the dephosphorylation pathway. Because the experimentally observed inactivation of CaMKII by PP1 accounts for this latter characteristic, we aimed at verifying whether a realistic model using reported parameters values can simulate the induction of either LTP or LTD, depending on the time and amplitude characteristics of the Ca2+ signal. Our simulations demonstrate that the experimentally observed bidirectional nature of Ca2+-dependent synaptic plasticity could be the consequence of the PP1-mediated inactivation of CaMKII.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2003.02693.x
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  • 5
    Electronic Resource
    Electronic Resource
    Caffeine-mediated induction of c-fos, zif-268 and arc expression through A1 receptors in the striatum: different interactions with the dopaminergic system (1999)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 11 (1999), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Adenosine and the adenosine receptor antagonist, caffeine, modulate locomotor activity and striatal neuropeptide expression through interactions with the dopaminergic system by mechanisms which remain partially undetermined. We adressed this question by using quantitative immunocytochemistry and in situ hybridization, combined with retrograde tracing of striatal neurons, to characterize the mechanism(s) leading to the striatal increase in the immediate early genes (IEG), c-fos, zif-268 and arc, following a single injection of caffeine or the A1 antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX). Caffeine and DPCPX induced c-fos, zif-268 and arc expression, both at mRNA and protein levels, in large proportions of striatonigral and striatopallidal neurons. The involvement of dopamine systems was evaluated by manipulations of the dopaminergic transmission. Quinpirole, a D2 agonist, almost completely blocked the caffeine-induced IEG increase in both striatopallidal and striatonigral neurons. Conversely, the lesion of the nigrostriatal pathway and the D1 antagonist SCH23390 abolished the caffeine effects in striatonigral neurons but had no or slight effect, respectively, on its action in striatopallidal neurons. These observations demonstrate that caffeine- and DPCPX-mediated IEG inductions involved different mechanisms in striatonigral and striatopallidal neurons through blockade of A1 receptors. Immediate early gene inductions result from a stimulation of dopamine release in striatonigral neurons and from activation of glutamate release and probably also acetylcholine release in striatopallidal neurons. These results also support the idea that, besides A2A receptors, adenosine acting at the A1 receptor plays pivotal functions in the basal ganglia physiology and that blockade of these receptors by specific or nonspecific antagonists, DPCPX and caffeine, may influence a broad range of neuronal functions in the striatum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.1999.00725.x
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  • 6
    Electronic Resource
    Electronic Resource
    Calretinin expression as a critical component in the control of dentate gyrus long-term potentiation induction in mice (1998)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 10 (1998), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have recently reported that mice homozygous (Cr–/–) for a null mutation in the calretinin gene have impaired long-term potentiation (LTP) induction in the dentate gyrus (S. Schurmans et al. (1997) Proc. Natl. Acad. Sci. USA, 94, 10415 ). Here, we investigated dentate LTP induction in mice heterozygous (Cr+/–) for the same mutation. Despite the presence of calretinin in neurons of these mice, although at reduced levels as compared with normal mice, LTP induction in dentate gyrus was totally impaired. Spatial memory and learning were found unaffected in Cr+/– mice, such as in Cr–/– mice. Altogether, our results suggest that calretinin is a critical component in the control of dentate synaptic plasticity in mice, and that levels of calretinin higher than those observed in Cr+/– mice are required to induce LTP in this area. The possible mechanisms leading to the absence of correlation between gene dosage and biological effects are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1998.00373.x
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  • 7
    Electronic Resource
    Electronic Resource
    Aggressiveness, hypoalgesia and high blood pressure in mice lacking the adenosine A 2a receptor (1997)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 388 (1997), S. 674-678 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Adenosine is released from metabolically active cells by facilitated diffusion, and is generated extracellularly by degradation of released ATP. It is a potent biological mediator that modulates the activity of numerous cell types, including various neuronal populations, platelets, neutrophils ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/388674a0
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  • 8
    Electronic Resource
    Electronic Resource
    CD34 immunoreactivity and interstitial cells of Cajal in the human and mouse gastrointestinal tract (2000)
    Springer
    Cell & tissue research 302 (2000), S. 145-153 
    Details
    ISSN: 1432-0878
    Keywords: Immunohistochemistry Confocal microscopy Co-localization Fibroblast-like cells Stromal tumors Mouse (C57 BL/6) Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Immunoreactivity for the tyrosine kinase receptor Kit (Kit-ir) is an established marker for the interstitial cells of Cajal (ICC) of the gut. Recently, the presence of CD34 immunoreactivity (CD34-ir) has been reported in Kit-ir ICC around the myenteric plexus in human small intestine. Conversely, we observed that CD34-ir labeled Kit-negative fibroblast-like cells, closely adjacent to, but distinct from, the Kit-ir ICC. The existence of cells expressing both CD34-ir and Kit-ir remains controversial. CD34-ir and Kit-ir were studied by high-resolution confocal microscopy on cryostat sections of human and murine gut as well as murine whole-mounts, using specific antibodies raised to human and murine CD34, respectively. CD34-ir labeled numerous cells in all parts of the gut, in man and in mouse. CD34-ir was consistently observed in Kit-negative cells, distinct from the closely adjacent Kit-ir ICC. Thin processes of both cell types intermingled extensively, often at the limit of resolution for light microscopy. CD34-ir was also observed in Kit-negative mesenchymal cells in the submucosa, in capillaries and in mesothelial cells. CD34-ir is not a marker for Kit-ir ICC in the human and murine gut. No CD34-ir, Kit-ir-expressing cells were encountered. Conversely, CD34-ir cells, closely adjacent to, but distinct from, Kit-ir ICC were consistently identified. The intimate relationship between these cells may offer an alternative explanation for reports of CD34 and Kit co-localization. The ontogeny and function of CD34-ir cells in the gut, as well as the origin of gastrointestinal stromal tumors, remain unclear
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410000264
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  • 9
    Electronic Resource
    Electronic Resource
    Distribution and ultrastructure of interstitial cells of Cajal in the mouse colon, using antibodies to Kit and Kit W-lacZ mice (2000)
    Springer
    Cell & tissue research 302 (2000), S. 155-170 
    Details
    ISSN: 1432-0878
    Keywords: Digestive tract Transgenic model β-Galactosidase Development Immunohistochemistry Histochemistry Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The roles of the interstitial cells of Cajal in the stomach and intestine are becoming increasingly clear. Interstitial cells of Cajal in the colon are less well known, however. We studied the development and distribution of the interstitial cells of Cajal in the mouse colon, using the tyrosine kinase receptor Kit as a marker. Sections and whole mounts were studied by confocal microscopy after double immunofluorescence with specific antibodies. The ultrastructure of Kit-expressing cells was examined by electron microcopy in Kit W-lacz /+ transgenic mice, which carry the lacz gene inserted in place of the first exon of the Kit gene. In the subserosa, the interstitial cells of Cajal formed a two-dimensional plexus. In the myenteric area, the interstitial cells of Cajal formed a dense plexus that gradually merged with the interstitial cells of Cajal in the outer half of the circular muscle. The inner half of the circular layer was devoid of interstitial cells of Cajal whereas in the submuscular region the interstitial cells of Cajal formed a two-dimensional plexus. Tertiary nerves with various chemical codings closely followed interstitial cell of Cajal processes. By electron microscopy, Kit-expressing cells in the outer parts of the musculature had scattered caveolae, inconspicuous basal lamina and numerous mitochondria, whereas in the submuscular region they had more pronounced myoid features. Kit-expressing cells in the mouse colon are identifiable as interstitial cells of Cajal by their ultrastructure. The interstitial cells of Cajal in the mouse colon mature postnatally. They are organized into a characteristic plexus, close to the nerves with various chemical codings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004419900170
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  • 10
    Electronic Resource
    Electronic Resource
    Expression of mRNA of parathyroid hormone-related peptide in fetal bones of the rat (1992)
    Springer
    Cell & tissue research 270 (1992), S. 597-600 
    Details
    ISSN: 1432-0878
    Keywords: Parathyroid hormone-related peptide ; Osteocalcin-mRNA ; In situ hybridization histochemistry ; Bone ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies have indicated that 19-dayold fetal long bones of the rat contain an adenylyl cyclase-stimulating activity antigenically related to parathyroid hormone-related peptide. To ascertain its origin, Northern blotting and in situ hybridization histochemistry were performed. Results demonstrate that mRNA of parathyroid hormone-related peptide is present in RNA extracted from fetal long bones of the rat and that cells responsible for its production are localized in the periosteum. These cells are not mature osteoblasts because they do not synthesize mRNA of osteocalcin. Thus the present study shows that parathyroid hormone-related peptide could be produced locally, at least in part, in the skeleton of fetal rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645063
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