The Experts below are selected from a list of 129 Experts worldwide ranked by ideXlab platform
Gregor Laube - One of the best experts on this subject based on the ideXlab platform.
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Synaptic localisation of agmatinase in rat cerebral cortex revealed by virtual pre-embedding
Amino acids, 2011Co-Authors: Vince I. Madai, D. Peters, R. W. Veh, Wolfram C. Poller, J. Berger, K. Paliege, René Bernard, Gregor LaubeAbstract:Light microscopic evidence suggested a synaptic role for agmatinase, an enzyme capable of inactivating the Putative Neurotransmitter and endogenous anti-depressant agmatine. Using electron microscopy and an alternative pre-embedding approach referred to as virtual pre-embedding, agmatinase was localised pre- and postsynaptically, to dendritic spines, spine and non-spine terminals, and dendritic profiles. In dendritic spines, labelling displayed a tendency towards the postsynaptic density. These results further strengthen a synaptic role for agmatine and strongly suggest a regulatory role for synaptically expressed agmatinase.
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The agmatine-degrading enzyme agmatinase: a key to agmatine signaling in rat and human brain?
Amino Acids, 2010Co-Authors: H.-g. Bernstein, Christian Derst, C. Stich, Harald Prüss, D. Peters, Michael Krauss, Bernhard Bogerts, R. W. Veh, Gregor LaubeAbstract:Agmatinase, an ureohydrolase belonging to the arginase family, is widely expressed in mammalian tissues including the brain. Here, it may serve two different functions, the inactivation of the arginine derivative agmatine, a Putative Neurotransmitter, and the formation of the diamine putrescine. In order to identify the cellular sources of agmatinase expression in the brain, we generated a polyclonal monospecific antibody against recombinant rat agmatinase. With immunocytochemistry, selected areas of rat and human brain were screened. Clearly, in both species agmatinase-like immunoreactivity was predominantly detected in distinct populations of neurons, especially cortical interneurons. Also, principal neurons in limbic regions like the habenula and in the cerebellum robustly expressed agmatinase protein. When comparing the overall agmatinase expression with immunocytochemical data available for agmatine and polyamine biosynthetic enzymes, the observed pattern may argue in favor of an agmatine inactivating function rather than fueling the alternative pathway of polyamine synthesis. The Putative Neurotransmitter agmatine is seemingly involved with mental disorders. Therefore, agmatinase may be similarly important for pathogenesis. The normal expression profile of the protein as described here may therefore be altered under pathological conditions.
Masahiro Asai - One of the best experts on this subject based on the ideXlab platform.
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Role of interleukin-1 in stress responses. A Putative Neurotransmitter.
Molecular neurobiology, 1995Co-Authors: Futoshi Shintani, Toshio Nakaki, Shigenobu Kanba, Ryuichi Kato, Masahiro AsaiAbstract:Recently, the central roles of interleukin-1 (IL-1) in physical stress responses have been attracting attention. Stress responses have been characterized as central neurohormonal changes, as well as behavioral and physiological changes. Administration of IL-1 has been shown to induce effects comparable to stress-induced changes. IL-1 acts on the brain, especially the hypothalamus, to enhance release of monoamines, such as norepinephrine, dopamine, and serotonin, as well as secretion of corticotropin-releasing hormone (CRH). IL-1-induced activation of the hypothalamo-pituitary-adrenal (HPA) axis in vivo depends on secretion of CRH, an intact pituitary, and the ventral noradrenergic bundle that innervates the CRH-containing neurons in the paraventricular nucleus of the hypothalamus. Recent studies have shown that IL-1 is present within neurons in the brain, suggesting that IL-1 functions in neuronal transmission. We showed that IL-1 in the brain is involved in the stress response, and that stress-induced activation of monoamine release and the HPA axis were inhibited by IL-1 receptor antagonist (IL-1Ra) administration directly into the rat hypothalamus. IL-1Ra has been known to exert a blocking effect on IL-1 by competitively inhibiting the binding of IL-1 to IL-1 receptors. In the latter part of this review, we will attempt to describe the relationship between central nervous system diseases, including psychological disorders, and the functions of IL-1 as a Putative Neurotransmitter.
Dionysia T. Theodosis - One of the best experts on this subject based on the ideXlab platform.
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Ultrastructural visualization and neurochemical characterization of spinal projections of primary sensory afferents from the nipple: combined use of transganglionic transport of HRP-WGA and glutamate immunocytochemistry.
Journal of Histochemistry and Cytochemistry, 1994Co-Authors: Philippe Rousselot, Dominique A Poulain, Dionysia T. TheodosisAbstract:We used transganglionic transport of the neuronal tracer horseradish peroxidase coupled to wheat germ agglutinin (HRP-WGA) and post-embedding immunogold staining to determine the spinal projections and neurochemical identity of sensory afferents originating from a discrete cutaneous area. After SC injection of tracer into the nipple of lactating rats and reaction with tetramethylbenzidine stabilized with diaminobenzidene (TMB-DAB) or DAB and cobalt (TMB-DAB-Co), we found labeled terminals in the internal part of the first two layers of the dorsal horn where they formed axodendritic synapses and, at times, central elements of glomeruli, synaptic complexes believed to be involved in the integration of sensory messages. Immunogold staining of ultra-thin sections of tissue reacted with TMB-DAB-Co revealed that many mammary afferents contained glutamate as Putative Neurotransmitter. This combined approach thus offers the possibility of marking a limited set of primary afferents, after capture of tracer by sens...
George D. Prell - One of the best experts on this subject based on the ideXlab platform.
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Vestibular neurons in the rat contain imidazoleacetic acid-ribotide, a Putative Neurotransmitter involved in blood pressure regulation.
The Journal of comparative neurology, 2007Co-Authors: Giovanni Martinelli, Victor L. Friedrich, George D. PrellAbstract:A substantial body of research has led to the recognition that the vestibular system participates in blood pressure modulation during active movements and changes in posture, and that this modulation is effected at least partly by the caudal vestibular nuclei. The I-4 isomer of imidazoleacetic acid-ribotide (IAA-RP) is a Putative Neurotransmitter/modulator that is thought to be an endogenous regulator of general sympathetic drive, particularly systemic blood pressure. The present study employed immunofluorescence and light and electron microscopic immunocytochemistry to visualize IAA-RP in the vestibular nuclei of adult male rats. The results demonstrate IAA-RP immunolabeling of subpopulations of vestibular neurons in the descending nucleus and the caudal half of the medial nucleus, with scattered immunostained vestibular neurons also present more rostrally. On the basis of double immunofluorescence staining for IAA-RP and calbindin, many of these ribotide-immunoreactive neurons appear to be innervated by cerebellar Purkinje cell afferents. Ultrastructural observations in the caudal vestibular nuclei confirm the IAA-RP immunolocalization in cell bodies and dendritic processes, and in some myelinated axons and presynaptic boutons. The regional distribution of IAA-RP immunoreactivity corresponds to the location of vestibular neurons involved in autonomic functions. The presence of IAA-RP in those neurons suggests that they participate specifically in vestibulo-autonomic regulation of blood pressure. The localization of immunostain in processes and terminals suggests that vestibulo-autonomic activity is subject to local feedback control. Overall, the observations offer a chemoanatomic basis for understanding the vestibular side effects commonly experienced by patients treated with clonidine and other imidazoline-related drugs.
Andrew G M Bulloch - One of the best experts on this subject based on the ideXlab platform.
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glutamate as a Putative Neurotransmitter in the mollusc lymnaea stagnalis
Neuroscience, 1996Co-Authors: O B Nesic, Ken Lukowiak, Neil S Magoski, K K Mckenney, Naweed I Syed, Andrew G M BullochAbstract:Abstract Bath-applied glutamate (10–1000 μ M) produced excitatory and inhibitory responses on numerous identified neurons of the mollusc Lymnaea stagnalis . Using both in situ and in vitro preparations, glutamate or glutamate agonists produced a depolarization in identified neurons right pedal dorsal 1 and right pedal dorsal 2 and 3. However, attempts to block glutamate-evoked responses with glutamate antagonists were unsuccessful. We examined a potential glutamatergic neuron, visceral dorsal 4. Exogenous application of the peptides (GDPFLRFamide and SDPFLRFamide) could mimic the inhibitory, but not the excitatory effects of visceral dorsal 4 on its postsynaptic cells, implying the presence of a second transmitter. We tested the possibility that glutamate is this second Neurotransmitter by using excitatory synapses between visceral dorsal 4 and postsynaptic cells right pedal dorsal 2 and 3, right pedal dorsal 1, visceral F group and right parietal B group neurons. Of all the Putative Neurotransmitters tested, only glutamate had consistent excitatory effects on these postsynaptic cells. Also, the amplitude of the right pedal dorsal 2 and 3 excitatory postsynaptic potentials was reduced in the presence of N -methyl- d -aspartate and other glutamate agonists, suggesting desensitization of the endogenous transmitter receptor. In conclusion, some identified Lymnaea neurons respond to glutamate via a receptor with novel pharmacological properties. Furthermore, a Lymnaea interneuron may employ glutamate as a transmitter at excitatory synapses.
