The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
Yu F Liu - One of the best experts on this subject based on the ideXlab platform.
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Vasoactive Intestinal Polypeptide gene expression in the developing human gastroIntestinal tract
Gastroenterology, 1992Co-Authors: Paul Facer, Anne E Bishop, Gonzalo Moscoso, Giorgio Terenghi, Yu F LiuAbstract:Expression of Vasoactive Intestinal Polypeptide has been shown, by immunocytochemistry and biochemical assay, to follow the craniocaudal neural colonization of the mammalian gut. The aim of this study was to use in situ hybridization to see if it could provide more information on Vasoactive Intestinal Polypeptide gene expression in the developing human gut. Immunocytochemistry of Vasoactive Intestinal Polypeptide and, to visualize the total innervation, protein gene product 9.5 was also applied. By 8 weeks of gestation, protein gene product 9.5-immunoreactive neurons had colonized the gut lengthwise (17% of Intestinal muscle area) but not transversely. Vasoactive Intestinal Polypeptide immunoreactivity was first detected at 9 weeks of gestation in a few nerve fibers of the upper gut, the origin of which could not be determined. Vasoactive Intestinal Polypeptide-immunoreactive ganglion cells were not seen until 18 weeks of gestation, whereas in situ hybridization showed messenger RNA in ganglion cells of the upper gut at 9 weeks. An adultlike pattern of peptide gene products (e.g., 2.5% and 3.1% of Intestinal mucosal or muscle area, respectively) was detected by 20 weeks' gestation. The finding that the Vasoactive Intestinal Polypeptide gene is expressed first in the upper human gut is consistent with craniocaudal neuronal colonization and maturation.
Gerhard F. Kieselbach - One of the best experts on this subject based on the ideXlab platform.
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Substance P and Vasoactive Intestinal Polypeptide in the streptozotocin-induced diabetic rat retina.
Investigative ophthalmology & visual science, 2001Co-Authors: Josef Troger, Susanne Neyer, Christine Heufler, Hartwig P. Huemer, Eduard Schmid, Ute Griesser, Martina T. Kralinger, Bernhard Kremser, Ivo Baldissera, Gerhard F. KieselbachAbstract:PURPOSE Little knowledge exists about how neurotransmitters behave in the diabetic retina. In this study, the authors measured the concentration of two neuropeptides, substance P and Vasoactive Intestinal Polypeptide, in the streptozotocin-induced diabetic rat retina in a time-dependent manner. METHODS The retinas of 1-, 3-, 5-, 8-, and 12-week diabetic rats were processed using a highly sensitive radioimmunoassay for both substance P and Vasoactive Intestinal Polypeptide. Furthermore, the peptide-immunoreactivities were characterized by high-pressure liquid chromatography. RESULTS Substance P and Vasoactive Intestinal Polypeptide were found to be significantly reduced with a maximum decrease of 28.6% (+/-6.7) and 64.5% (+/-10.7) after 5 weeks, respectively. The peptide-immunoreactivities were found in a major peak coeluting with the synthetic peptides indicating that the quantitative values measured by radioimmunoassay represent the authentic peptides. CONCLUSIONS The reduction of substance P and Vasoactive Intestinal Polypeptide is in clear contrast to the amino acid transmitters GABA and glycine, which have been shown to be elevated in this early stage of diabetic retinopathy. This finding is important for three reasons: First, the decrease may result in reduced excitability of inner retinal neurons, as both peptides are known to modulate the excitability of these neurons; second, the decrease may be the consequence of a depressing and/or damaging effect by excitotoxins; and third, it may help explain why neovascularizations do not occur in this animal model, although VEGF is massively upregulated, as substance P is a very potent vascular growth factor.
Paul Facer - One of the best experts on this subject based on the ideXlab platform.
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Vasoactive Intestinal Polypeptide gene expression in the developing human gastroIntestinal tract
Gastroenterology, 1992Co-Authors: Paul Facer, Anne E Bishop, Gonzalo Moscoso, Giorgio Terenghi, Yu F LiuAbstract:Expression of Vasoactive Intestinal Polypeptide has been shown, by immunocytochemistry and biochemical assay, to follow the craniocaudal neural colonization of the mammalian gut. The aim of this study was to use in situ hybridization to see if it could provide more information on Vasoactive Intestinal Polypeptide gene expression in the developing human gut. Immunocytochemistry of Vasoactive Intestinal Polypeptide and, to visualize the total innervation, protein gene product 9.5 was also applied. By 8 weeks of gestation, protein gene product 9.5-immunoreactive neurons had colonized the gut lengthwise (17% of Intestinal muscle area) but not transversely. Vasoactive Intestinal Polypeptide immunoreactivity was first detected at 9 weeks of gestation in a few nerve fibers of the upper gut, the origin of which could not be determined. Vasoactive Intestinal Polypeptide-immunoreactive ganglion cells were not seen until 18 weeks of gestation, whereas in situ hybridization showed messenger RNA in ganglion cells of the upper gut at 9 weeks. An adultlike pattern of peptide gene products (e.g., 2.5% and 3.1% of Intestinal mucosal or muscle area, respectively) was detected by 20 weeks' gestation. The finding that the Vasoactive Intestinal Polypeptide gene is expressed first in the upper human gut is consistent with craniocaudal neuronal colonization and maturation.
Axel Schleicher - One of the best experts on this subject based on the ideXlab platform.
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Modular distribution of Vasoactive Intestinal Polypeptide in the rat barrel cortex: Changes induced by neonatal removal of vibrissae
Neuroscience, 1998Co-Authors: Ferenc Hajós, Karl Zilles, Péter Sótonyi, A. Zsarnovszky, Katalin Gallatz, Axel SchleicherAbstract:The distribution of Vasoactive Intestinal Polypeptide-immunoreactive neuronal structures in the barrel cortex (posteromedial barrel subfield) of adult rats was analysed after unilateral removal of the vibrissal follicles of row C in neonatal rats. The hypothesis was tested whether the distribution of Vasoactive Intestinal Polypeptide-immunoreactive structures depends on the normal anatomical organization of the specific sensory input. After three months survival the distribution of the Vasoactive Intestinal Polypeptide-immunoreactive structures was morphometrically evaluated. This approach revealed alterations in the contralateral posteromedial barrel subfield, where the disappearance of barrel row C and a substantial increase in size mainly of barrel row D, but also of other rows could be detected. Increase in row D included both barrels and the interspace (septal segments between barrels in one row). As Vasoactive Intestinal Polypeptide immunoreactivity of the barrel field was found previously to be localized in synaptic boutons involved in symmetric synapses, our present findings suggest that (i) the interspace is enriched in inhibitory Vasoactive Intestinal Polypeptide-immunoreactive synapses as opposed to the excitatory thalamocortical input reaching the barrel hollow, (ii) the spatial distribution of the Vasoactive Intestinal Polypeptide system in the barrel cortex is closely associated with the neuronal organization of the sensory input and reacts with a considerable plasticity to lesion-induced changes of the input, and (iii) the compensatory barrel hypertrophy in a row neighbouring the deafferented row involves an increasing number of Vasoactive Intestinal Polypeptide-immunoreactive synapses per barrel.
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Vasoactive Intestinal Polypeptide immunoreactive structures in the mouse barrel field
Brain research, 1993Co-Authors: Karl Zilles, Ferenc Hajós, András Csillag, Mihály Kálmán, Péter Sótonyi, Axel SchleicherAbstract:Immunohistochemistry for Vasoactive Intestinal Polypeptide was carried out in tangentially cut vibratome sections of the barrel cortex in adult mice. Sections through layer IV have revealed an association between the cytoarchitectonically visible modular organization of barrels and the distribution of immunoreactive axon terminals. These terminals are preferentially localized in the side region of a barrel, whereas the hollow shows a relative scarcity of these structures as shown with image analysis. This finding is the first direct demonstration of a modular distribution of Vasoactive Intestinal Polypeptide-containing axon terminals in the neocortex.
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Matching localization of Vasoactive Intestinal Polypeptide (VIP) and VIP-receptor at pre- and postsynaptic sites in the mouse visual cortex.
Journal of neurocytology, 1993Co-Authors: András Csillag, Karl Zilles, Ferenc Hajós, Axel Schleicher, Hannsjörg SchröderAbstract:Vibratome sections of the mouse occipital cortex were processed by double label immunohistochemistry to demonstrate the localization of the receptor for Vasoactive Intestinal Polypeptide and the peptide itself. The receptor was found to be distributed in the cytoplasm and major dendrites of numerous cortical cells, mainly pyramidal neurons. Vasoactive Intestinal Polypeptide, on the other hand, occurred in a population of non-pyramidal neurons and axonal boutons. Image analysis revealed a close spatial association of peptide-containing presynaptic terminals with receptor-containing cells. Ultrastructurally, these connections represented symmetrical axo-somatic and axo-dendritic synapses. Our findings demonstrate a matching histological localization of Vasoactive Intestinal Polypeptide and its receptor in the brain.
Mitchell L. Schubert - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Vasoactive Intestinal Polypeptide on Gastric Acid Secretion Is Predominantly Mediated by Somatostatin
Gastroenterology, 1991Co-Authors: Mitchell L. SchubertAbstract:The mechanism of action of Vasoactive Intestinal Polypeptide on gastric acid secretion was examined in the isolated, luminally perfused mouse stomach. Vasoactive Intestinal Polypeptide caused a weak, transient increase in basal and histamine-stimulated acid secretion and a sustained increase in somatostatin secretion. The sustained increase in somatostatin despite return of acid to basal levels indicated that somatostatin secretion was a direct response to Vasoactive Intestinal Polypeptide and not mediated by intraluminal acidification. The increase in somatostatin secretion was partly responsible for the weak, transient nature of the acid response since incubation with pertussis toxin, which is known to block the inhibitory effect of exogenous and endogenous somatostatin, converted the acid response to a sustained increase throughout the period of stimulation. The inhibitory influence of somatostatin was confirmed with selective Vasoactive Intestinal Polypeptide antagonists. The antagonists inhibited Vasoactive Intestinal Polypeptide-induced somatostatin secretion but caused a sustained increase in acid secretion. The pattern of response implied that somatostatin secretion was more sensitive than acid secretion to Vasoactive Intestinal Polypeptide and Vasoactive Intestinal Polypeptide antagonists and that suppression of somatostatin eliminated the main inhibitory influence on acid secretion. In addition, both Vasoactive Intestinal Polypeptide antagonists inhibited basal somatostatin secretion, implying that input from tonically active Vasoactive Intestinal Polypeptide neurons is responsible, at least in part, for basal somatostatin secretion.
