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Sample records for controls ampa receptor

  1. AMPA receptor ligands

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Mellor, Ian

    2004-01-01

    Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player in the f......Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player...... in the formation of memory. Hence, ligands affecting AMPARs are highly important for the study of the structure and function of this receptor, and in this regard polyamine-based ligands, particularly polyamine toxins, are unique as they selectively block Ca2+ -permeable AMPARs. Indeed, endogenous intracellular...

  2. Stargazin Modulation of AMPA Receptors

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    Sana A. Shaikh

    2016-10-01

    Full Text Available Fast excitatory synaptic signaling in the mammalian brain is mediated by AMPA-type ionotropic glutamate receptors. In neurons, AMPA receptors co-assemble with auxiliary proteins, such as stargazin, which can markedly alter receptor trafficking and gating. Here, we used luminescence resonance energy transfer measurements to map distances between the full-length, functional AMPA receptor and stargazin expressed in HEK293 cells and to determine the ensemble structural changes in the receptor due to stargazin. In addition, we used single-molecule fluorescence resonance energy transfer to study the structural and conformational distribution of the receptor and how this distribution is affected by stargazin. Our nanopositioning data place stargazin below the AMPA receptor ligand-binding domain, where it is well poised to act as a scaffold to facilitate the long-range conformational selection observations seen in single-molecule experiments. These data support a model of stargazin acting to stabilize or select conformational states that favor activation.

  3. Uncompetitive antagonism of AMPA receptors

    DEFF Research Database (Denmark)

    Andersen, Trine F; Tikhonov, Denis B; Bølcho, Ulrik

    2006-01-01

    Philanthotoxins are uncompetitive antagonists of Ca2+-permeable AMPA receptors presumed to bind to the pore-forming region, but a detailed molecular mechanism for this interaction is missing. Here a small library of novel philanthotoxins was designed and synthesized using a solid-phase strategy. ...

  4. Agonist discrimination between AMPA receptor subtypes

    DEFF Research Database (Denmark)

    Coquelle, T; Christensen, J K; Banke, T G

    2000-01-01

    The lack of subtype-selective compounds for AMPA receptors (AMPA-R) led us to search for compounds with such selectivity. Homoibotenic acid analogues were investigated at recombinant GluR1o, GluR2o(R), GluR3o and GluR1o + 3o receptors expressed in Sf9 insect cells and affinities determined in [3H...

  5. AMPA receptor mediated excitotoxicity in neocortical neurons is developmentally regulated and dependent upon receptor desensitization

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1998-01-01

    with a fast and rapidly desensitizing response, this could explain the relatively low toxicity produced by 500 microM AMPA. This was investigated by blocking AMPA receptor desensitization with cyclothiazide. Using a lower concentration (25 microM) of AMPA, addition of 50 microM cyclothiazide increased...... the AMPA induced excitotoxicity in cultured cortical neurons at all DIV except for DIV 2. This combination of AMPA + cyclothiazide yielded 77% cell death for DIV 12 cultures. In contrast to the results observed with 500 microM AMPA, the neurotoxicity mediated directly by AMPA receptors when desensitization...

  6. Enhanced odor discrimination and impaired olfactory memory by spatially controlled switch of AMPA receptors.

    Directory of Open Access Journals (Sweden)

    Derya R Shimshek

    2005-11-01

    Full Text Available Genetic perturbations of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs are widely used to dissect molecular mechanisms of sensory coding, learning, and memory. In this study, we investigated the role of Ca2+-permeable AMPARs in olfactory behavior. AMPAR modification was obtained by depletion of the GluR-B subunit or expression of unedited GluR-B(Q, both leading to increased Ca2+ permeability of AMPARs. Mice with this functional AMPAR switch, specifically in forebrain, showed enhanced olfactory discrimination and more rapid learning in a go/no-go operant conditioning task. Olfactory memory, however, was dramatically impaired. GluR-B depletion in forebrain was ectopically variable ("mosaic" among individuals and strongly correlated with decreased olfactory memory in hippocampus and cortex. Accordingly, memory was rescued by transgenic GluR-B expression restricted to piriform cortex and hippocampus, while enhanced odor discrimination was independent of both GluR-B variability and transgenic GluR-B expression. Thus, correlated differences in behavior and levels of GluR-B expression allowed a mechanistic and spatial dissection of olfactory learning, discrimination, and memory capabilities.

  7. Enhanced odor discrimination and impaired olfactory memory by spatially controlled switch of AMPA receptors.

    Science.gov (United States)

    Shimshek, Derya R; Bus, Thorsten; Kim, Jinhyun; Mihaljevic, Andre; Mack, Volker; Seeburg, Peter H; Sprengel, Rolf; Schaefer, Andreas T

    2005-11-01

    Genetic perturbations of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) are widely used to dissect molecular mechanisms of sensory coding, learning, and memory. In this study, we investigated the role of Ca2+-permeable AMPARs in olfactory behavior. AMPAR modification was obtained by depletion of the GluR-B subunit or expression of unedited GluR-B(Q), both leading to increased Ca2+ permeability of AMPARs. Mice with this functional AMPAR switch, specifically in forebrain, showed enhanced olfactory discrimination and more rapid learning in a go/no-go operant conditioning task. Olfactory memory, however, was dramatically impaired. GluR-B depletion in forebrain was ectopically variable ("mosaic") among individuals and strongly correlated with decreased olfactory memory in hippocampus and cortex. Accordingly, memory was rescued by transgenic GluR-B expression restricted to piriform cortex and hippocampus, while enhanced odor discrimination was independent of both GluR-B variability and transgenic GluR-B expression. Thus, correlated differences in behavior and levels of GluR-B expression allowed a mechanistic and spatial dissection of olfactory learning, discrimination, and memory capabilities.

  8. TARPs differentially decorate AMPA receptors to specify neuropharmacology.

    Science.gov (United States)

    Kato, Akihiko S; Gill, Martin B; Yu, Hong; Nisenbaum, Eric S; Bredt, David S

    2010-05-01

    Transmembrane AMPA receptor regulatory proteins (TARPs) are the first identified auxiliary subunits for a neurotransmitter-gated ion channel. Although initial studies found that stargazin, the prototypical TARP, principally chaperones AMPA receptors, subsequent research demonstrated that it also regulates AMPA receptor kinetics and synaptic waveforms. Recent studies have identified a diverse collection of TARP isoforms--types Ia, Ib II--that distinctly regulate AMPA receptor trafficking, gating and neuropharmacology. These TARP isoforms are heterogeneously expressed in specific neuronal populations and can differentially sculpt synaptic transmission and plasticity. Whole-genome analyses also link multiple TARP loci to childhood epilepsy, schizophrenia and bipolar disorder. TARPs emerge as vital components of excitatory synapses that participate both in signal transduction and in neuropsychiatric disorders. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. Preferential assembly of heteromeric kainate and AMPA receptor amino terminal domains.

    Science.gov (United States)

    Zhao, Huaying; Lomash, Suvendu; Chittori, Sagar; Glasser, Carla; Mayer, Mark L; Schuck, Peter

    2017-10-23

    Ion conductivity and the gating characteristics of tetrameric glutamate receptor ion channels are determined by their subunit composition. Competitive homo- and hetero-dimerization of their amino-terminal domains (ATDs) is a key step controlling assembly. Here we measured systematically the thermodynamic stabilities of homodimers and heterodimers of kainate and AMPA receptors using fluorescence-detected sedimentation velocity analytical ultracentrifugation. Measured affinities span many orders of magnitude, and complexes show large differences in kinetic stabilities. The association of kainate receptor ATD dimers is generally weaker than the association of AMPA receptor ATD dimers, but both show a general pattern of increased heterodimer stability as compared to the homodimers of their constituents, matching well physiologically observed receptor combinations. The free energy maps of AMPA and kainate receptor ATD dimers provide a framework for the interpretation of observed receptor subtype combinations and possible assembly pathways.

  10. Regulation of AMPA Receptor Trafficking by Protein Ubiquitination

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    Jocelyn Widagdo

    2017-10-01

    Full Text Available The molecular mechanisms underlying plastic changes in the strength and connectivity of excitatory synapses have been studied extensively for the past few decades and remain the most attractive cellular models of learning and memory. One of the major mechanisms that regulate synaptic plasticity is the dynamic adjustment of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA-type glutamate receptor content on the neuronal plasma membrane. The expression of surface AMPA receptors (AMPARs is controlled by the delicate balance between the biosynthesis, dendritic transport, exocytosis, endocytosis, recycling and degradation of the receptors. These processes are dynamically regulated by AMPAR interacting proteins as well as by various post-translational modifications that occur on their cytoplasmic domains. In the last few years, protein ubiquitination has emerged as a major regulator of AMPAR intracellular trafficking. Dysregulation of AMPAR ubiquitination has also been implicated in the pathophysiology of Alzheimer’s disease. Here we review recent advances in the field and provide insights into the role of protein ubiquitination in regulating AMPAR membrane trafficking and function. We also discuss how aberrant ubiquitination of AMPARs contributes to the pathogenesis of various neurological disorders, including Alzheimer’s disease, chronic stress and epilepsy.

  11. LOCALIZATION OF NMDA AND AMPA RECEPTORS IN RAT BARREL FIELD

    NARCIS (Netherlands)

    JAARSMA, D; SEBENS, JB; KORF, J

    1991-01-01

    The aim of this study was to asses the distribution of N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-S-methyl-4-isoxazole propionic acid (AMPA) receptors in the barrel field of rat primary somatosensory (SI) cortex using light-microscopic in vitro autoradiography. NMDA receptors were labeled

  12. Aryl- and heteroaryl-substituted phenylalanines as AMPA receptor ligands

    DEFF Research Database (Denmark)

    Szymańska, Ewa; Chałupnik, Paulina; Johansen, Tommy Nørskov

    2017-01-01

    in radioligand binding assays at native rat ionotropic glutamate receptors. The most interesting compound in this series, (RS)-2-amino-3-(3'-hydroxy-5-(1H-pyrazol-4-yl)-[1,1'-biphenyl]-3-yl)propanoic acid 7e, showed the binding affinity of 4.6 µM for native AMPA receptors and almost 5-fold lower affinity...

  13. Are AMPA Receptor Positive Allosteric Modulators Potential Pharmacotherapeutics for Addiction?

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    Lucas R. Watterson

    2013-12-01

    Full Text Available Positive allosteric modulators (PAMs of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA receptors are a diverse class of compounds that increase fast excitatory transmission in the brain. AMPA PAMs have been shown to facilitate long-term potentiation, strengthen communication between various cortical and subcortical regions, and some of these compounds increase the production and release of brain-derived neurotrophic factor (BDNF in an activity-dependent manner. Through these mechanisms, AMPA PAMs have shown promise as broad spectrum pharmacotherapeutics in preclinical and clinical studies for various neurodegenerative and psychiatric disorders. In recent years, a small collection of preclinical animal studies has also shown that AMPA PAMs may have potential as pharmacotherapeutic adjuncts to extinction-based or cue-exposure therapies for the treatment of drug addiction. The present paper will review this preclinical literature, discuss novel data collected in our laboratory, and recommend future research directions for the possible development of AMPA PAMs as anti-addiction medications.

  14. Regulation of AMPA receptor localization in lipid rafts

    Science.gov (United States)

    Hou, Qingming; Huang, Yunfei; Amato, Stephen; Snyder, Solomon H.; Huganir, Richard L.; Man, Heng-Ye

    2009-01-01

    Lipid rafts are special microdomains enriched in cholesterol, sphingolipids and certain proteins, and play important roles in a variety of cellular functions including signal transduction and protein trafficking. We report that in cultured cortical and hippocampal neurons the distribution of lipid rafts is development-dependent. Lipid rafts in mature neurons exist on the entire cell-surface and display a high degree of mobility. AMPA receptors co-localize and associate with lipid rafts in the plasma membrane. The association of AMPARs with rafts is under regulation; through the NOS–NO pathway, NMDA receptor activity increases AMPAR localization in rafts. During membrane targeting, AMPARs insert into or at close proximity of the surface raft domains. Perturbation of lipid rafts dramatically suppresses AMPA receptor exocytosis, resulting in significant reduction in AMPAR cell-surface expression. PMID:18411055

  15. Increased NMDA and AMPA receptor densities in the anterior cingulate cortex in schizophrenia

    International Nuclear Information System (INIS)

    Zavitsanou, K.; Huang, X.-F.

    2002-01-01

    Full text: The anterior cingulate cortex (ACC) is a brain area of potential importance to our understanding of the pathophysiology of schizophrenia. Since a disturbed balance between excitatory and inhibitory activity is suggested to occur in the ACC in schizophrenia, the present study has focused on the analysis of binding of [ 3 H]MK801, [ 3 H]AMPA and [ 3 H]kainate, radioligands which respectively label the NMDA, AMPA and kainate receptors of the ionotropic glutamate receptor family in the ACC of 10 schizophrenia patients and 10 matched controls, using quantitative autoradiography. AMPA receptor densities were higher in cortical layer II whereas NMDA receptor densities were higher in cortical layers II-III in the ACC of both control and schizophrenia group. In contrast, kainate receptors displayed the highest density in cortical layer V. [ 3 H]AMPA binding was significantly increased by 25% in layer II in the schizophrenia group as compared to the control group. Similarly, a significant 17% increase of [ 3 H]MK801 binding was observed in layers II-III in the schizophrenia group. No statistically significant differences were observed for [ 3 H] kainate binding between the two groups. These results suggest that ionotropic glutamate receptors are differentially altered in the ACC of schizophrenia. The increase in [ 3 H]AMPA and [ 3 H]MK801 binding points to a postsynaptic compensation for impaired glutamatergic neurotransmission in the ACC in schizophrenia. Such abnormality could lead to an imbalance between the excitatory and inhibitory neurotransmission in this brain area that may contribute to the emergence of some schizophrenia symptoms. Copyright (2002) Australian Neuroscience Society

  16. Regulation of AMPA receptor localization in lipid rafts

    OpenAIRE

    Hou, Qingming; Huang, Yunfei; Amato, Stephen; Snyder, Solomon H.; Huganir, Richard L.; Man, Heng-Ye

    2008-01-01

    Lipid rafts are special microdomains enriched in cholesterol, sphingolipids and certain proteins, and play important roles in a variety of cellular functions including signal transduction and protein trafficking. We report that in cultured cortical and hippocampal neurons the distribution of lipid rafts is development-dependent. Lipid rafts in mature neurons exist on the entire cell-surface and display a high degree of mobility. AMPA receptors co-localize and associate with lipid rafts in the...

  17. Stress induces pain transition by potentiation of AMPA receptor phosphorylation.

    Science.gov (United States)

    Li, Changsheng; Yang, Ya; Liu, Sufang; Fang, Huaqiang; Zhang, Yong; Furmanski, Orion; Skinner, John; Xing, Ying; Johns, Roger A; Huganir, Richard L; Tao, Feng

    2014-10-08

    Chronic postsurgical pain is a serious issue in clinical practice. After surgery, patients experience ongoing pain or become sensitive to incident, normally nonpainful stimulation. The intensity and duration of postsurgical pain vary. However, it is unclear how the transition from acute to chronic pain occurs. Here we showed that social defeat stress enhanced plantar incision-induced AMPA receptor GluA1 phosphorylation at the Ser831 site in the spinal cord and greatly prolonged plantar incision-induced pain. Interestingly, targeted mutation of the GluA1 phosphorylation site Ser831 significantly inhibited stress-induced prolongation of incisional pain. In addition, stress hormones enhanced GluA1 phosphorylation and AMPA receptor-mediated electrical activity in the spinal cord. Subthreshold stimulation induced spinal long-term potentiation in GluA1 phosphomimetic mutant mice, but not in wild-type mice. Therefore, spinal AMPA receptor phosphorylation contributes to the mechanisms underlying stress-induced pain transition. Copyright © 2014 the authors 0270-6474/14/3413737-10$15.00/0.

  18. Examination of Org 26576, an AMPA receptor positive allosteric modulator, in patients diagnosed with major depressive disorder: an exploratory, randomized, double-blind, placebo-controlled trial.

    Science.gov (United States)

    Nations, Kari R; Dogterom, Peter; Bursi, Roberta; Schipper, Jacques; Greenwald, Scott; Zraket, David; Gertsik, Lev; Johnstone, Jack; Lee, Allen; Pande, Yogesh; Ruigt, Ge; Ereshefsky, Larry

    2012-12-01

    Org 26576 acts by modulating ionotropic AMPA-type glutamate receptors to enhance glutamatergic neurotransmission. The aim of this Phase 1b study (N=54) was to explore safety, tolerability, pharmacokinetics, and pharmacodynamics of Org 26576 in depressed patients. Part I (N=24) evaluated the maximum tolerated dose (MTD) and optimal titration schedule in a multiple rising dose paradigm (range 100 mg BID to 600 mg BID); Part II (N=30) utilized a parallel groups design (100 mg BID, 400 mg BID, placebo) to examine all endpoints over a 28-day dosing period. Based on the number of moderate intensity adverse events reported at the 600 mg BID dose level, the MTD established in Part I was 450 mg BID. Symptomatic improvement as measured by the Montgomery-Asberg Depression Rating Scale was numerically greater in the Org 26576 groups than in the placebo group in both study parts. In Part II, the 400 mg BID dose was associated with improvements in executive functioning and speed of processing cognitive tests. Org 26576 was also associated with growth hormone increases and cortisol decreases at the end of treatment but did not influence prolactin or brain-derived neurotrophic factor. The quantitative electroencephalogram index Antidepressant Treatment Response at Week 1 was able to significantly predict symptomatic response at endpoint in the active treatment group, as was early improvement in social acuity. Overall, Org 26576 demonstrated good tolerability and pharmacokinetic properties in depressed patients, and pharmacodynamic endpoints suggested that it may show promise in future well-controlled, adequately powered proof of concept trials.

  19. Positioning of AMPA Receptor-Containing Endosomes Regulates Synapse Architecture

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    Marta Esteves da Silva

    2015-11-01

    Full Text Available Lateral diffusion in the membrane and endosomal trafficking both contribute to the addition and removal of AMPA receptors (AMPARs at postsynaptic sites. However, the spatial coordination between these mechanisms has remained unclear, because little is known about the dynamics of AMPAR-containing endosomes. In addition, how the positioning of AMPAR-containing endosomes affects synapse organization and functioning has never been directly explored. Here, we used live-cell imaging in hippocampal neuron cultures to show that intracellular AMPARs are transported in Rab11-positive recycling endosomes, which frequently enter dendritic spines and depend on the microtubule and actin cytoskeleton. By using chemically induced dimerization systems to recruit kinesin (KIF1C or myosin (MyosinV/VI motors to Rab11-positive recycling endosomes, we controlled their trafficking and found that induced removal of recycling endosomes from spines decreases surface AMPAR expression and PSD-95 clusters at synapses. Our data suggest a mechanistic link between endosome positioning and postsynaptic structure and composition.

  20. Modern approaches to the design of memory and cognitive function stimulants based on AMPA receptor ligands

    International Nuclear Information System (INIS)

    Grigoriev, V V; Proshin, A N; Kinzirsky, A S; Bachurin, Sergey O

    2009-01-01

    Data on the structure and properties of compounds acting on AMPA receptors, the key subtype of ionotropic glutamate receptors of the mammalian central nervous system, are analyzed. Data on the role of these receptors in provision of memory and cognitive function formation and impairment processes are presented. The attention is focused on the modern views on the mechanisms of AMPA receptor desensitization and deactivation and action of substances affecting these processes. The structures of key positive modulators of AMPA receptors are given. The problems of application of these substances as therapeutic means for preventing and treating neurodegenerative and psychoneurological diseases are discussed. Bibliography - 121 references.

  1. Modern approaches to the design of memory and cognitive function stimulants based on AMPA receptor ligands

    Energy Technology Data Exchange (ETDEWEB)

    Grigoriev, V V; Proshin, A N; Kinzirsky, A S; Bachurin, Sergey O [Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2009-05-31

    Data on the structure and properties of compounds acting on AMPA receptors, the key subtype of ionotropic glutamate receptors of the mammalian central nervous system, are analyzed. Data on the role of these receptors in provision of memory and cognitive function formation and impairment processes are presented. The attention is focused on the modern views on the mechanisms of AMPA receptor desensitization and deactivation and action of substances affecting these processes. The structures of key positive modulators of AMPA receptors are given. The problems of application of these substances as therapeutic means for preventing and treating neurodegenerative and psychoneurological diseases are discussed. Bibliography - 121 references.

  2. Modern approaches to the design of memory and cognitive function stimulants based on AMPA receptor ligands

    Science.gov (United States)

    Grigoriev, V. V.; Proshin, A. N.; Kinzirsky, A. S.; Bachurin, Sergey O.

    2009-05-01

    Data on the structure and properties of compounds acting on AMPA receptors, the key subtype of ionotropic glutamate receptors of the mammalian central nervous system, are analyzed. Data on the role of these receptors in provision of memory and cognitive function formation and impairment processes are presented. The attention is focused on the modern views on the mechanisms of AMPA receptor desensitization and deactivation and action of substances affecting these processes. The structures of key positive modulators of AMPA receptors are given. The problems of application of these substances as therapeutic means for preventing and treating neurodegenerative and psychoneurological diseases are discussed. Bibliography — 121 references.

  3. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...

  4. Hormonal regulation of AMPA receptor trafficking and memory formation

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    Harmen J Krugers

    2009-10-01

    Full Text Available Humans and rodents retain memories for stressful events very well. The facilitated retention of these memories is normally very useful. However, in susceptible individuals a variety of pathological conditions may develop in which memories related to stressful events remain inappropriately present, such as in post-traumatic stress disorder. The memory enhancing effects of stress are mediated by hormones, such as norepinephrine and glucocorticoids which are released during stressful experiences. Here we review recently identified molecular mechanisms that underlie the effects of stress hormones on synaptic efficacy and learning and memory. We discuss AMPA receptors as major target for stress hormones and describe a model in which norepinephrine and glucocorticoids are able to strengthen and prolong different phases of stressful memories.

  5. Brain Region-Specific Effects of cGMP-Dependent Kinase II Knockout on AMPA Receptor Trafficking and Animal Behavior

    Science.gov (United States)

    Kim, Seonil; Pick, Joseph E.; Abera, Sinedu; Khatri, Latika; Ferreira, Danielle D. P.; Sathler, Matheus F.; Morison, Sage L.; Hofmann, Franz; Ziff, Edward B.

    2016-01-01

    Phosphorylation of GluA1, a subunit of AMPA receptors (AMPARs), is critical for AMPAR synaptic trafficking and control of synaptic transmission. cGMP-dependent protein kinase II (cGKII) mediates this phosphorylation, and cGKII knockout (KO) affects GluA1 phosphorylation and alters animal behavior. Notably, GluA1 phosphorylation in the KO…

  6. Structure and organization of heteromeric AMPA-type glutamate receptors.

    Science.gov (United States)

    Herguedas, Beatriz; García-Nafría, Javier; Cais, Ondrej; Fernández-Leiro, Rafael; Krieger, James; Ho, Hinze; Greger, Ingo H

    2016-04-29

    AMPA-type glutamate receptors (AMPARs), which are central mediators of rapid neurotransmission and synaptic plasticity, predominantly exist as heteromers of the subunits GluA1 to GluA4. Here we report the first AMPAR heteromer structures, which deviate substantially from existing GluA2 homomer structures. Crystal structures of the GluA2/3 and GluA2/4 N-terminal domains reveal a novel compact conformation with an alternating arrangement of the four subunits around a central axis. This organization is confirmed by cysteine cross-linking in full-length receptors, and it permitted us to determine the structure of an intact GluA2/3 receptor by cryogenic electron microscopy. Two models in the ligand-free state, at resolutions of 8.25 and 10.3 angstroms, exhibit substantial vertical compression and close associations between domain layers, reminiscent of N-methyl-D-aspartate receptors. Model 1 resembles a resting state and model 2 a desensitized state, thus providing snapshots of gating transitions in the nominal absence of ligand. Our data reveal organizational features of heteromeric AMPARs and provide a framework to decipher AMPAR architecture and signaling. Copyright © 2016, American Association for the Advancement of Science.

  7. Synaptic activity regulates AMPA receptor trafficking through different recycling pathways

    Science.gov (United States)

    Zheng, Ning; Jeyifous, Okunola; Munro, Charlotte; Montgomery, Johanna M; Green, William N

    2015-01-01

    Changes in glutamatergic synaptic strength in brain are dependent on AMPA-type glutamate receptor (AMPAR) recycling, which is assumed to occur through a single local pathway. In this study, we present evidence that AMPAR recycling occurs through different pathways regulated by synaptic activity. Without synaptic stimulation, most AMPARs recycled in dynamin-independent endosomes containing the GTPase, Arf6. Few AMPARs recycled in dynamin-dependent endosomes labeled by transferrin receptors (TfRs). AMPAR recycling was blocked by alterations in the GTPase, TC10, which co-localized with Arf6 endosomes. TC10 mutants that reduced AMPAR recycling had no effect on increased AMPAR levels with long-term potentiation (LTP) and little effect on decreased AMPAR levels with long-term depression. However, internalized AMPAR levels in TfR-containing recycling endosomes increased after LTP, indicating increased AMPAR recycling through the dynamin-dependent pathway with synaptic plasticity. LTP-induced AMPAR endocytosis is inconsistent with local recycling as a source of increased surface receptors, suggesting AMPARs are trafficked from other sites. DOI: http://dx.doi.org/10.7554/eLife.06878.001 PMID:25970033

  8. Differential trafficking of AMPA receptors following activation of NMDA receptors and mGluRs

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    Sanderson Thomas M

    2011-07-01

    Full Text Available Abstract The removal of AMPA receptors from synapses is a major component of long-term depression (LTD. How this occurs, however, is still only partially understood. To investigate the trafficking of AMPA receptors in real-time we previously tagged the GluA2 subunit of AMPA receptors with ecliptic pHluorin and studied the effects of NMDA receptor activation. In the present study we have compared the effect of NMDA receptor and group I mGluR activation, using GluA2 tagged with super ecliptic pHluorin (SEP-GluA2 expressed in cultured hippocampal neurons. Surprisingly, agonists of the two receptors, which are both able to induce chemical forms of LTD, had clearly distinct effects on AMPA receptor trafficking. In agreement with our previous work we found that transient NMDA receptor activation results in an initial decrease in surface GluA2 from extrasynaptic sites followed by a delayed reduction in GluA2 from puncta (putative synapses. In contrast, transient activation of group I mGluRs, using DHPG, led to a pronounced but more delayed decrease in GluA2 from the dendritic shafts. Surprisingly, there was no average change in the fluorescence of the puncta. Examination of fluorescence at individual puncta, however, indicated that alterations did take place, with some puncta showing an increase and others a decrease in fluorescence. The effects of DHPG were, like DHPG-induced LTD, prevented by treatment with a protein tyrosine phosphatase (PTP inhibitor. The electrophysiological correlate of the effects of DHPG in the SEP-GluA2 infected cultures was a reduction in mEPSC frequency with no change in amplitude. The implications of these findings for the initial mechanisms of expression of both NMDA receptor- and mGluR-induced LTD are discussed.

  9. Autoinactivation of the stargazin-AMPA receptor complex: subunit-dependency and independence from physical dissociation.

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    Artur Semenov

    Full Text Available Agonist responses and channel kinetics of native α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA receptors are modulated by transmembrane accessory proteins. Stargazin, the prototypical accessory protein, decreases desensitization and increases agonist potency at AMPA receptors. Furthermore, in the presence of stargazin, the steady-state responses of AMPA receptors show a gradual decline at higher glutamate concentrations. This "autoinactivation" has been assigned to physical dissociation of the stargazin-AMPA receptor complex and suggested to serve as a protective mechanism against overactivation. Here, we analyzed autoinactivation of GluA1-A4 AMPA receptors (all flip isoform expressed in the presence of stargazin. Homomeric GluA1, GluA3, and GluA4 channels showed pronounced autoinactivation indicated by the bell-shaped steady-state dose response curves for glutamate. In contrast, homomeric GluA2i channels did not show significant autoinactivation. The resistance of GluA2 to autoinactivation showed striking dependence on the splice form as GluA2-flop receptors displayed clear autoinactivation. Interestingly, the resistance of GluA2-flip containing receptors to autoinactivation was transferred onto heteromeric receptors in a dominant fashion. To examine the relationship of autoinactivation to physical separation of stargazin from the AMPA receptor, we analyzed a GluA4-stargazin fusion protein. Notably, the covalently linked complex and separately expressed proteins expressed a similar level of autoinactivation. We conclude that autoinactivation is a subunit and splice form dependent property of AMPA receptor-stargazin complexes, which involves structural rearrangements within the complex rather than any physical dissociation.

  10. The essential role of AMPA receptor GluR2 subunit RNA editing in the normal and diseased brain

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    Amanda Lorraine Wright

    2012-04-01

    Full Text Available AMPA receptors are comprised of different combinations of GluR1-GluR4 (also known as GluA1-GluA4 and GluR-A to GluR-D subunits. The GluR2 subunit is subject to Q/R site RNA editing by the ADAR2 enzyme, which converts a codon for glutamine (Q, present in the GluR2 gene, to a codon for arginine (R found in the mRNA. AMPA receptors are calcium (Ca2+-permeable if they contain the unedited GluR2(Q subunit or if they lack the GluR2 subunit. While most AMPA receptors in the brain contain the edited GluR2(R subunit and are therefore Ca2+-impermeable, recent evidence suggests that Ca2+-permeable GluR2-lacking AMPA receptors are important in synaptic plasticity and learning. However, the presence of Ca2+-permeable AMPA receptors containing unedited GluR2 leads to excitotoxic cell loss. Recent studies have indicated that RNA editing of GluR2 is deregulated in diseases, such as amyotrophic lateral sclerosis (ALS, as well in acute neurodegenerative conditions, such as ischemia. More recently, studies have investigated the regulation of RNA editing and possible causes for its deregulation during disease. In this review, we will explore the role of GluR2 RNA editing in the healthy and diseased brain and outline new insights into the mechanisms that control this process.

  11. The AMPA receptor-associated protein Shisa7 regulates hippocampal synaptic function and contextual memory

    NARCIS (Netherlands)

    Schmitz, Leanne J M; Klaassen, Remco V; Ruiperez-Alonso, Marta; Zamri, Azra Elia; Stroeder, Jasper; Rao-Ruiz, Priyanka; Lodder, Johannes C; van der Loo, Rolinka J; Mansvelder, Huib D; Smit, August B; Spijker, Sabine; Verhage, Matthijs

    2017-01-01

    Glutamatergic synapses rely on AMPA receptors (AMPARs) for fast synaptic transmission and plasticity. AMPAR auxiliary proteins regulate receptor trafficking, and modulate receptor mobility and its biophysical properties. The AMPAR auxiliary protein Shisa7 (CKAMP59) has been shown to interact with

  12. 1,2,3-triazolyl amino acids as AMPA receptor ligands

    DEFF Research Database (Denmark)

    Stanley, Nathan J.; Pedersen, Daniel Sejer; Nielsen, Birgitte

    2010-01-01

    The central nervous system glutamate receptors are an important target for drug discovery. Herein we report initial investigations into the synthesis and glutamate receptor activity of 1,2,3-triazolyl amino acids. Two compounds were found to be selective AMPA receptor ligands, which warrant further...

  13. Individual stress vulnerability is predicted by short-term memory and AMPA receptor subunit ratio in the hippocampus.

    Science.gov (United States)

    Schmidt, Mathias V; Trümbach, Dietrich; Weber, Peter; Wagner, Klaus; Scharf, Sebastian H; Liebl, Claudia; Datson, Nicole; Namendorf, Christian; Gerlach, Tamara; Kühne, Claudia; Uhr, Manfred; Deussing, Jan M; Wurst, Wolfgang; Binder, Elisabeth B; Holsboer, Florian; Müller, Marianne B

    2010-12-15

    Increased vulnerability to aversive experiences is one of the main risk factors for stress-related psychiatric disorders as major depression. However, the molecular bases of vulnerability, on the one hand, and stress resilience, on the other hand, are still not understood. Increasing clinical and preclinical evidence suggests a central involvement of the glutamatergic system in the pathogenesis of major depression. Using a mouse paradigm, modeling increased stress vulnerability and depression-like symptoms in a genetically diverse outbred strain, and we tested the hypothesis that differences in AMPA receptor function may be linked to individual variations in stress vulnerability. Vulnerable and resilient animals differed significantly in their dorsal hippocampal AMPA receptor expression and AMPA receptor binding. Treatment with an AMPA receptor potentiator during the stress exposure prevented the lasting effects of chronic social stress exposure on physiological, neuroendocrine, and behavioral parameters. In addition, spatial short-term memory, an AMPA receptor-dependent behavior, was found to be predictive of individual stress vulnerability and response to AMPA potentiator treatment. Finally, we provide evidence that genetic variations in the AMPA receptor subunit GluR1 are linked to the vulnerable phenotype. Therefore, we propose genetic variations in the AMPA receptor system to shape individual stress vulnerability. Those individual differences can be predicted by the assessment of short-term memory, thereby opening up the possibility for a specific treatment by enhancing AMPA receptor function.

  14. Stargazin regulates AMPA receptor trafficking through adaptor protein complexes during long-term depression

    Science.gov (United States)

    Matsuda, Shinji; Kakegawa, Wataru; Budisantoso, Timotheus; Nomura, Toshihiro; Kohda, Kazuhisa; Yuzaki, Michisuke

    2013-11-01

    Long-term depression (LTD) underlies learning and memory in various brain regions. Although postsynaptic AMPA receptor trafficking mediates LTD, its underlying molecular mechanisms remain largely unclear. Here we show that stargazin, a transmembrane AMPA receptor regulatory protein, forms a ternary complex with adaptor proteins AP-2 and AP-3A in hippocampal neurons, depending on its phosphorylation state. Inhibiting the stargazin-AP-2 interaction disrupts NMDA-induced AMPA receptor endocytosis, and inhibiting that of stargazin-AP-3A abrogates the late endosomal/lysosomal trafficking of AMPA receptors, thereby upregulating receptor recycling to the cell surface. Similarly, stargazin’s interaction with AP-2 or AP-3A is necessary for low-frequency stimulus-evoked LTD in CA1 hippocampal neurons. Thus, stargazin has a crucial role in NMDA-dependent LTD by regulating two trafficking pathways of AMPA receptors—transport from the cell surface to early endosomes and from early endosomes to late endosomes/lysosomes—through its sequential binding to AP-2 and AP-3A.

  15. Mechanism of Ca2+/calmodulin-dependent kinase II regulation of AMPA receptor gating

    DEFF Research Database (Denmark)

    Kristensen, Anders Skov; Jenkins, Meagan A; Banke, Tue G

    2011-01-01

    The function, trafficking and synaptic signaling of AMPA receptors are tightly regulated by phosphorylation. Ca(2+)/calmodulin-dependent kinase II (CaMKII) phosphorylates the GluA1 AMPA receptor subunit at Ser831 to increase single-channel conductance. We show that CaMKII increases the conductanc...

  16. Chronic intermittent hypoxia impairs heart rate responses to AMPA and NMDA and induces loss of glutamate receptor neurons in nucleus ambiguous of F344 rats.

    Science.gov (United States)

    Yan, Binbin; Li, Lihua; Harden, Scott W; Gozal, David; Lin, Ying; Wead, William B; Wurster, Robert D; Cheng, Zixi Jack

    2009-02-01

    Chronic intermittent hypoxia (CIH), as occurs in sleep apnea, impairs baroreflex-mediated reductions in heart rate (HR) and enhances HR responses to electrical stimulation of vagal efferent. We tested the hypotheses that HR responses to activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and N-methyl-D-aspartate (NMDA) receptors in the nucleus ambiguous (NA) are reduced in CIH-exposed rats and that this impairment is associated with degeneration of glutamate receptor (GluR)-immunoreactive NA neurons. Fischer 344 rats (3-4 mo) were exposed to room air (RA) or CIH for 35-50 days (n = 18/group). At the end of the exposures, AMPA (4 pmol, 20 nl) and NMDA (80 pmol, 20 nl) were microinjected into the same location of the left NA (-200 microm to +200 microm relative to caudal end of area postrema; n = 6/group), and HR and arterial blood pressure responses were measured. In addition, brain stem sections at the level of -800, -400, 0, +400, and +800 microm relative to obex were processed for AMPA and NMDA receptor immunohistochemistry. The number of NA neurons expressing AMPA receptors and NMDA receptors (NMDARs) was quantified. Compared with RA, we found that after CIH 1) HR responses to microinjection of AMPA into the left NA were reduced (RA -290 +/- 30 vs. CIH -227 +/- 15 beats/min, P neurons expressing GluRs contributes to impaired baroreflex control of HR in rats exposed to CIH.

  17. Differential effect of NMDA and AMPA receptor blockade on protein synthesis in the rat infarct borderzone

    DEFF Research Database (Denmark)

    Christensen, Thomas; Bruhn, T; Frank, L

    1996-01-01

    treated with either saline, MK-801 (5 mg/kg i.p.) or NBQX (30 mg/kg i.p. x 3) were subjected to permanent MCAO. Regional CPSR and volumes of gray matter structures displaying normal CPSR were measured in coronal cryosections of the brain by quantitative autoradiography following an i.v. bolus injection....... Treatment with MK-801 significantly increased the volume of tissue with normal CPSR in the ischemic hemisphere compared to controls, whereas this was not seen with NBQX treatment. The results suggest that MK-801 and NBQX have different effects on peri-infarct protein synthesis after MCAO. Since both......We investigated whether the known neuroprotective effects of two selective glutamate receptor antagonists, the NMDA antagonist MK-801 and the AMPA antagonist NBQX, are reflected in the regional cerebral protein synthesis rates (CPSR) in rats with middle cerebral artery occlusion (MCAO). Rats...

  18. Studies on Aryl-Substituted Phenylalanines: Synthesis, Activity, and Different Binding Modes at AMPA Receptors

    DEFF Research Database (Denmark)

    Szymanska, Ewa; Frydenvang, Karla Andrea; Pickering, Darryl S

    2016-01-01

    , not previously seen for amino acid-based AMPA receptor antagonists, X-ray crystal structures of both eutomers in complex with the GluA2 ligand binding domain were solved. The cocrystal structures of (S)-37 and (R)-38 showed similar interactions of the amino acid parts but unexpected and different orientations...

  19. Enhanced AMPA receptor function promotes cerebellar long-term depression rather than potentiation

    NARCIS (Netherlands)

    van Beugen, Boeke J; Qiao, Xin; Simmons, Dana H; De Zeeuw, Chris I; Hansel, Christian

    2014-01-01

    Ampakines are allosteric modulators of AMPA receptors that facilitate hippocampal long-term potentiation (LTP) and learning, and have been considered for the treatment of cognition and memory deficits. Here, we show that the ampakine CX546 raises the amplitude and slows the decay time of excitatory

  20. An antagonist of calcium permeable AMPA receptors, IEM1460: Anticonvulsant action in immature rats?

    Czech Academy of Sciences Publication Activity Database

    Szczurowska, Ewa; Mareš, Pavel

    2015-01-01

    Roč. 109, Jan 2015 (2015), s. 106-113 ISSN 0920-1211 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : cortical epileptic afterdischarges * AMPA receptors * ontogeny * rat Subject RIV: FH - Neurology Impact factor: 2.237, year: 2015

  1. AMPA Receptor Endocytosis in Rat Perirhinal Cortex Underlies Retrieval of Object Memory

    Science.gov (United States)

    Cazakoff, Brittany N.; Howland, John G.

    2011-01-01

    Mechanisms consistent with long-term depression in the perirhinal cortex (PRh) play a fundamental role in object recognition memory; however, whether AMPA receptor endocytosis is involved in distinct phases of recognition memory is not known. To address this question, we used local PRh infusions of the cell membrane-permeable Tat-GluA2[subscript…

  2. Activity-Mediated AMPA Receptor Remodeling, Driven by Alternative Splicing in the Ligand-Binding Domain

    Czech Academy of Sciences Publication Activity Database

    Penn, A.C.; Balík, Aleš; Wozny, Ch.; Cais, O.; Greger, I. H.

    2012-01-01

    Roč. 76, č. 3 (2012), s. 503-510 ISSN 0896-6273 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : RNA * AMPA receptors * hippocampus Subject RIV: ED - Physiology Impact factor: 15.766, year: 2012

  3. Structural basis for AMPA receptor activation and ligand selectivity

    DEFF Research Database (Denmark)

    Hogner, A; Kastrup, Jette Sandholm Jensen; Jin, R

    2002-01-01

    Glutamate is the principal excitatory neurotransmitter within the mammalian CNS, playing an important role in many different functions in the brain such as learning and memory. In this study, a combination of molecular biology, X-ray structure determinations, as well as electrophysiology...... with Br-HIBO and ACPA have allowed us to explain the molecular mechanism behind this selectivity and to identify key residues for ligand recognition. The agonists induce the same degree of domain closure as AMPA, except for Br-HIBO, which shows a slightly lower degree of domain closure. An excellent...

  4. Changes in flip/flop splicing of astroglial AMPA receptors in human temporal lobe epilepsy.

    Science.gov (United States)

    Seifert, Gerald; Schröder, Wolfgang; Hinterkeuser, Stefan; Schumacher, Thekla; Schramm, Johannes; Steinhäuser, Christian

    2002-01-01

    Recent data suggested a role for glial cells in epilepsy. This study sought to identify and functionally characterize AMPA receptors expressed by astrocytes in human hippocampal tissue resected from patients with intractable temporal lobe epilepsy. Patch-clamp and fast application methods were combined to investigate astrocytes in situ and after fresh isolation from the stratum radiatum of the hippocampal CA1 subfield. Relying on presurgical and histopathologic analysis, we divided human specimens into two groups, Ammon's horn sclerosis (AHS) and lesion-associated epilepsy. Fast application of glutamate and kainate evoked receptor currents in all cells studied. Reversal-potential analysis revealed an intermediate Ca2+ permeability of the receptor channels that did not vary between the two groups of patients. However, preapplication of the AMPA receptor-specific modulator, cyclothiazide, disclosed differences in flip-flop splicing. This treatment considerably enhanced the receptor conductance, with potentiation being significantly stronger in cells from AHS specimens compared with lesion-associated cells, suggesting upregulation of AMPA receptor flip splice variants in astrocytes of the sclerotic tissue. Compelling evidence has been accumulated showing direct and rapid signaling between neurons and glial cells. Our data suggest that in AHS patients, neuronally released glutamate will lead to an enhanced and prolonged depolarization of astrocytes, which might be involved in seizure generation and spread in this particular condition of human temporal lobe epilepsy.

  5. Opposite modulation of brain stimulation reward by NMDA and AMPA receptors in the ventral tegmental area.

    Science.gov (United States)

    Ducrot, Charles; Fortier, Emmanuel; Bouchard, Claude; Rompré, Pierre-Paul

    2013-01-01

    Previous studies have shown that blockade of ventral tegmental area (VTA) glutamate N-Methyl-D-Aspartate (NMDA) receptors induces reward, stimulates forward locomotion and enhances brain stimulation reward. Glutamate induces two types of excitatory response on VTA neurons, a fast and short lasting depolarization mediated by α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors and a longer lasting depolarization mediated by NMDA receptors. A role for the two glutamate receptors in modulation of VTA neuronal activity is evidenced by the functional change in AMPA and NMDA synaptic responses that result from repeated exposure to reward. Since both receptors contribute to the action of glutamate on VTA neuronal activity, we studied the effects of VTA AMPA and NMDA receptor blockade on reward induced by electrical brain stimulation. Experiments were performed on rats trained to self-administer electrical pulses in the medial posterior mesencephalon. Reward thresholds were measured with the curve-shift paradigm before and for 2 h after bilateral VTA microinjections of the AMPA antagonist, NBQX (2,3,-Dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(f)quinoxaline-7-sulfonamide, 0, 80, and 800 pmol/0.5 μl/side) and of a single dose (0.825 nmol/0.5 μl/side) of the NMDA antagonist, PPPA (2R,4S)-4-(3-Phosphonopropyl)-2-piperidinecarboxylic acid). NBQX produced a dose-dependent increase in reward threshold with no significant change in maximum rate of responding. Whereas PPPA injected at the same VTA sites produced a significant time dependent decrease in reward threshold and increase in maximum rate of responding. We found a negative correlation between the magnitude of the attenuation effect of NBQX and the enhancement effect of PPPA; moreover, NBQX and PPPA were most effective when injected, respectively, into the anterior and posterior VTA. These results suggest that glutamate acts on different receptor sub-types, most likely located on different VTA neurons, to

  6. Opposite modulation of brain stimulation reward by NMDA and AMPA receptors in the ventral tegmental area.

    Directory of Open Access Journals (Sweden)

    Charles eDucrot

    2013-10-01

    Full Text Available Previous studies have shown that blockade of ventral midbrain (VM glutamate N-Methyl-D-Aspartate (NMDA receptors induces reward, stimulates forward locomotion and enhances brain stimulation reward. Glutamate induces two types of excitatory response on VM neurons, a fast and short lasting depolarisation mediated by a-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA receptors and a longer lasting depolarization mediated by NMDA receptors. A role for the two glutamate receptors in modulation of VM neuronal activity is evidenced by the functional change in AMPA and NMDA synaptic responses that result from repeated exposure to reward. Since both receptors contribute to the action of glutamate on VM neuronal activity, we studied the effects of VM AMPA and NMDA receptor blockade on reward induced by electrical brain stimulation. Experiments were performed on rats trained to self-administer electrical pulses in the medial posterior mesencephalon. Reward thresholds were measured with the curve-shift paradigm before and for two hours after bilateral VM microinjections of the AMPA antagonist, NBQX (2,3,-Dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(fquinoxaline-7-sulfonamide, 0, 80, and 800 pmol/0.5ul/side and of a single dose (0.825 nmol/0.5ul/side of the NMDA antagonist, PPPA (2R,4S-4-(3-Phosphonopropyl-2-piperidinecarboxylic acid. NBQX produced a dose-dependent increase in reward threshold with no significant change in maximum rate of responding. Whereas PPPA injected at the same VM sites produced a significant time dependent decrease in reward threshold and increase in maximum rate of responding. We found a negative correlation between the magnitude of the attenuation effect of NBQX and the enhancement effect of PPPA; moreover, NBQX and PPPA were most effective when injected respectively into the anterior and posterior VM. These results suggest that glutamate acts on different receptor sub-types, most likely located on different VM neurons, to modulate

  7. The SOL-2/Neto auxiliary protein modulates the function of AMPA-subtype ionotropic glutamate receptors.

    Science.gov (United States)

    Wang, Rui; Mellem, Jerry E; Jensen, Michael; Brockie, Penelope J; Walker, Craig S; Hoerndli, Frédéric J; Hauth, Linda; Madsen, David M; Maricq, Andres V

    2012-09-06

    The neurotransmitter glutamate mediates excitatory synaptic transmission by gating ionotropic glutamate receptors (iGluRs). AMPA receptors (AMPARs), a subtype of iGluR, are strongly implicated in synaptic plasticity, learning, and memory. We previously discovered two classes of AMPAR auxiliary proteins in C. elegans that modify receptor kinetics and thus change synaptic transmission. Here, we have identified another auxiliary protein, SOL-2, a CUB-domain protein that associates with both the related auxiliary subunit SOL-1 and with the GLR-1 AMPAR. In sol-2 mutants, behaviors dependent on glutamatergic transmission are disrupted, GLR-1-mediated currents are diminished, and GLR-1 desensitization and pharmacology are modified. Remarkably, a secreted variant of SOL-1 delivered in trans can rescue sol-1 mutants, and this rescue depends on in cis expression of SOL-2. Finally, we demonstrate that SOL-1 and SOL-2 have an ongoing role in the adult nervous system to control AMPAR-mediated currents. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. PICK1 interacts with ABP/GRIP to regulate AMPA receptor trafficking.

    Science.gov (United States)

    Lu, Wei; Ziff, Edward B

    2005-08-04

    PICK1 and ABP/GRIP bind to the AMPA receptor (AMPAR) GluR2 subunit C terminus. Transfer of the receptor from ABP/GRIP to PICK1, facilitated by GluR2 S880 phosphorylation, may initiate receptor trafficking. Here we report protein interactions that regulate these steps. The PICK1 BAR domain interacts intermolecularly with the ABP/GRIP linker II region and intramolecularly with the PICK1 PDZ domain. Binding of PKCalpha or GluR2 to the PICK1 PDZ domain disrupts the intramolecular interaction and facilitates the PICK1 BAR domain association with ABP/GRIP. Interference with the PICK1-ABP/GRIP interaction impairs S880 phosphorylation of GluR2 by PKC and decreases the constitutive surface expression of GluR2, the NMDA-induced endocytosis of GluR2, and recycling of internalized GluR2. We suggest that the PICK1 interaction with ABP/GRIP is a critical step in controlling GluR2 trafficking.

  9. Effects of visual deprivation during brain development on expression of AMPA receptor subunits in rat’s hippocampus

    Directory of Open Access Journals (Sweden)

    Sayyed Alireza Talaei

    2015-06-01

    Conclusion: Dark rearing of rats during critical period of brain development changes the relative expression and also arrangement of both AMPA receptor subunits, GluR1 and GluR2 in the hippocampus, age dependently.

  10. Synthesis and enantiopharmacology of new AMPA-kainate receptor agonists

    DEFF Research Database (Denmark)

    Conti, P; De Amici, M; De Sarro, G

    1999-01-01

    . The convulsant properties of all the compounds were evaluated in vivo on DBA/2 mice after icv injection. CIP-A showed a convulsant activity, measured as tonus and clonus seizures, 18-65 times higher than that produced by AMPA. It was also quite active after ip administration, since it induced seizures in mice...... at doses as low as 3.2 nmol/mouse. On the basis of the above-reported results we prepared and tested the enantiomers of CIP-A and CIP-B, obtained by reacting (S)-3,4-didehydroproline and (R)-3,4-didehydroproline, respectively, with ethoxycarbonylformonitrile oxide. In all the tests the S-form, CIP...

  11. The antidepressant tianeptine reverts synaptic AMPA receptor defects caused by deficiency of CDKL5.

    Science.gov (United States)

    Tramarin, Marco; Rusconi, Laura; Pizzamiglio, Lara; Barbiero, Isabella; Peroni, Diana; Scaramuzza, Linda; Guilliams, Tim; Cavalla, David; Antonucci, Flavia; Kilstrup-Nielsen, Charlotte

    2018-06-15

    Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene cause a complex neurological disorder, characterized by infantile seizures, impairment of cognitive and motor skills and autistic features. Loss of Cdkl5 in mice affects dendritic spine maturation and dynamics but the underlying molecular mechanisms are still far from fully understood. Here we show that Cdkl5 deficiency in primary hippocampal neurons leads to deranged expression of the alpha-amino-3-hydroxy-5-methyl-4-iso-xazole propionic acid receptors (AMPA-R). In particular, a dramatic reduction of expression of the GluA2 subunit occurs concomitantly with its hyper-phosphorylation on Serine 880 and increased ubiquitination. Consequently, Cdkl5 silencing skews the composition of membrane-inserted AMPA-Rs towards the GluA2-lacking calcium-permeable form. Such derangement is likely to contribute, at least in part, to the altered synaptic functions and cognitive impairment linked to loss of Cdkl5. Importantly, we find that tianeptine, a cognitive enhancer and antidepressant drug, known to recruit and stabilise AMPA-Rs at the synaptic sites, can normalise the expression of membrane inserted AMPA-Rs as well as the number of PSD-95 clusters, suggesting its therapeutic potential for patients with mutations in CDKL5.

  12. Ketamine-induced inhibition of glycogen synthase kinase-3 contributes to the augmentation of AMPA receptor signaling

    Science.gov (United States)

    Beurel, Eléonore; Grieco, Steven F; Amadei, Celeste; Downey, Kimberlee; Jope, Richard S

    2016-01-01

    Objectives Sub-anesthetic doses of ketamine have been found to provide rapid antidepressant actions, indicating that the cellular signaling systems targeted by ketamine are potential sites for therapeutic intervention. Ketamine acts as an antagonist of N-methyl-D-aspartate (NMDA) receptors, and animal studies indicate that subsequent augmentation of signaling by α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors is critical for the antidepressant outcome. Methods In this study, we tested if the inhibitory effect of ketamine on glycogen synthase kinase-3 (GSK3) affected hippocampal cell-surface AMPA receptors using immunoblotting of membrane and synaptosomal extracts from wild-type and GSK3 knockin mice. Results Treatment with an antidepressant dose of ketamine increased the hippocampal membrane level of the AMPA glutamate receptor (GluA)1 subunit, but did not alter the localization of GluA2, GluA3, or GluA4. This effect of ketamine was abrogated in GSK3 knockin mice expressing mutant GSK3 that cannot be inhibited by ketamine, demonstrating that ketamine-induced inhibition of GSK3 is necessary for up-regulation of cell surface AMPA GluA1 subunits. AMPA receptor trafficking is regulated by post-synaptic density-95 (PSD-95), a substrate for GSK3. Ketamine treatment decreased the hippocampal membrane level of phosphorylated PSD-95 on Thr-19, the target of GSK3 that promotes AMPA receptor internalization. Conclusions These results demonstrate that ketamine-induced inhibition of GSK3 causes reduced phosphorylation of PSD-95, diminishing the internalization of AMPA GluA1 subunits to allow for augmented signaling through AMPA receptors following ketamine treatment. PMID:27687706

  13. Antihypertensive drug Valsartan promotes dendritic spine density by altering AMPA receptor trafficking

    Science.gov (United States)

    Sohn, Young In; Lee, Nathanael J.; Chung, Andrew; Saavedra, Juan M.; Turner, R. Scott; Pak, Daniel T. S.; Hoe, Hyang-Sook

    2013-01-01

    Recent studies demonstrated that the antihypertensive drug Valsartan improved spatial and episodic memory in mouse models of Alzheimer’s Disease (AD) and human subjects with hypertension. However, the molecular mechanism by which Valsartan can regulate cognitive function is still unknown. Here, we investigated the effect of Valsartan on dendritic spine formation in primary hippocampal neurons, which is correlated with learning and memory. Interestingly, we found that Valsartan promotes spinogenesis in developing and mature neurons. In addition, we found that Valsartan increases the puncta number of PSD-95 and trends toward an increase in the puncta number of synaptophysin. Moreover, Valsartan increased the cell surface levels of AMPA receptors and selectively altered the levels of spinogenesis-related proteins, including CaMKIIα and phospho-CDK5. These data suggest that Valsartan may promote spinogenesis by enhancing AMPA receptor trafficking and synaptic plasticity signaling. PMID:24012668

  14. Involvement of AMPA receptors in the antidepressant-like effects of dextromethorphan in mice.

    Science.gov (United States)

    Nguyen, Linda; Matsumoto, Rae R

    2015-12-15

    Dextromethorphan (DM) is an antitussive with rapid acting antidepressant potential based on pharmacodynamic similarities to ketamine. Building upon our previous finding that DM produces antidepressant-like effects in the mouse forced swim test (FST), the present study aimed to establish the antidepressant-like actions of DM in the tail suspension test (TST), another well-established model predictive of antidepressant efficacy. Additionally, using the TST and FST, we investigated the role of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors in the antidepressant-like properties of DM because accumulating evidence suggests that AMPA receptors play an important role in the pathophysiology of depression and may contribute to the efficacy of antidepressant medications, including that of ketamine. We found that DM displays antidepressant-like effects in the TST similar to the conventional and fast acting antidepressants characterized by imipramine and ketamine, respectively. Moreover, decreasing the first-pass metabolism of DM by concomitant administration of quinidine (CYP2D6 inhibitor) potentiated antidepressant-like actions, implying DM itself has antidepressant efficacy. Finally, in both the TST and FST, pretreatment with the AMPA receptor antagonist NBQX (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide) significantly attenuated the antidepressant-like behavior elicited by DM. Together, the data show that DM exerts antidepressant-like actions through AMPA receptors, further suggesting DM may act as a safe and effective fast acting antidepressant drug. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Facilitation of AMPA receptor synaptic delivery as a molecular mechanism for cognitive enhancement

    DEFF Research Database (Denmark)

    Knafo, Shira; Venero, César; Sánchez-Puelles, Cristina

    2012-01-01

    ) that enhances spatial learning and memory in rats. We have now investigated the cellular and molecular basis of this cognitive enhancement, using biochemical, morphological, electrophysiological, and behavioral analyses. We have found that FGL triggers a long-lasting enhancement of synaptic transmission......MKII activation. These results provide a mechanistic link between facilitation of AMPA receptor synaptic delivery and improved hippocampal-dependent learning, induced by a pharmacological cognitive enhancer....

  16. 3’-Deoxyadenosine (Cordycepin) Produces a Rapid and Robust Antidepressant Effect via Enhancing Prefrontal AMPA Receptor Signaling Pathway

    Science.gov (United States)

    Li, Bai; Hou, Yangyang; Zhu, Ming; Bao, Hongkun; Nie, Jun; Zhang, Grace Y.; Shan, Liping; Yao, Yao; Du, Kai; Yang, Hongju; Li, Meizhang; Zheng, Bingrong; Xu, Xiufeng; Xiao, Chunjie; Du, Jing

    2016-01-01

    Background: The development of rapid and safe antidepressants for the treatment of major depression is in urgent demand. Converging evidence suggests that glutamatergic signaling seems to play important roles in the pathophysiology of depression. Methods: We studied the antidepressant effects of 3’-deoxyadenosine (3’-dA, Cordycepin) and the critical role of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor in male CD-1 mice via behavioral and biochemical experiments. After 3’-dA treatment, the phosphorylation and synaptic localization of the AMPA receptors GluR1 and GluR2 were determined in the prefrontal cortex (PFC) and hippocampus (HIP). The traditional antidepressant imipramine was applied as a positive control. Results: We found that an injection of 3’-dA led to a rapid and robust antidepressant effect, which was significantly faster and stronger than imipramine, after 45min in tail suspension and forced swim tests. This antidepressant effect remained after 5 days of treatment with 3’-dA. Unlike the psycho-stimulants, 3’-dA did not show a hyperactive effect in the open field test. After 45min or 5 days of treatment, 3’-dA enhanced GluR1 S845 phosphorylation in both the PFC and HIP. In addition, after 45min of treatment, 3’-dA significantly up-regulated GluR1 S845 phosphorylation and GluR1, but not GluR2 levels, at the synapses in the PFC. After 5 days of treatment, 3’-dA significantly enhanced GluR1 S845 phosphorylation and GluR1, but not GluR2, at the synapses in the PFC and HIP. Moreover, the AMPA-specific antagonist GYKI 52466 was able to block the rapid antidepressant effects of 3’-dA. Conclusion: This study identified 3’-dA as a novel rapid antidepressant with clinical potential and multiple beneficial mechanisms, particularly in regulating the prefrontal AMPA receptor signaling pathway. PMID:26443809

  17. Early-life seizures alter synaptic calcium-permeable AMPA receptor function and plasticity

    Science.gov (United States)

    Lippman-Bell, Jocelyn J.; Zhou, Chengwen; Sun, Hongyu; Feske, Joel S.; Jensen, Frances E.

    2016-01-01

    Calcium (Ca2+)-mediated1 signaling pathways are critical to synaptic plasticity. In adults, the NMDA glutamate receptor (NMDAR) represents a major route for activity-dependent synaptic Ca2+ entry. However, during neonatal development, when synaptic plasticity is high, many AMPA glutamate receptors (AMPARs) are also permeable to Ca2+ (CP-AMPAR) due to low GluA2 subunit expression, providing an additional route for activity- and glutamate-dependent Ca2+ influx and subsequent signaling. Therefore, altered hippocampal Ca2+ signaling may represent an age-specific pathogenic mechanism. We thus aimed to assess Ca2+ responses 48 hours after hypoxia-induced neonatal seizures (HS) in postnatal day (P)10 rats, a post-seizure time point at which we previously reported LTP attenuation. We found that Ca2+ responses were higher in brain slices from post-HS rats than in controls and this increase was CP-AMPAR-dependent. To determine whether synaptic CP-AMPAR expression was also altered post-HS, we assessed the expression of GluA2 at hippocampal synapses and the expression of long-term depression (LTD), which has been linked to the presence of synaptic GluA2. Here we report a decrease 48 hours after HS in synaptic GluA2 expression at synapses and LTD in hippocampal CA1. Given the potentially critical role of AMPAR trafficking in disease progression, we aimed to establish whether post-seizure in vivo AMPAR antagonist treatment prevented the enhanced Ca2+ responses, changes in GluA2 synaptic expression, and diminished LTD. We found that NBQX treatment prevents all three of these post-seizure consequences, further supporting a critical role for AMPARs as an age-specific therapeutic target. PMID:27521497

  18. Distribution of AMPA-type glutamate receptor subunits in the chick visual system

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    Pires R.S.

    1997-01-01

    Full Text Available Several glutamate receptor (GluR subunits have been characterized during the past few years. In the present study, subunit-specific antisera were used to determine the distribution of the AMPA-type glutamate receptor subunits GluR1-4 in retinorecipient areas of the chick brain. Six white leghorn chicks (Gallus gallus, 7-15 days old, unknown sex were deeply anesthetized and perfused with 4% buffered paraformaldehyde and brain sections were stained using immunoperoxidase techniques. The AMPA-type glutamate receptor subunits GluR1, GluR2/3 and GluR4 were present in several retinorecipient areas, with varying degrees of colocalization. For example, perikarya in layers 2, 3, and 5 of the optic tectum contained GluR1, whereas GluR2/3 subunits appeared mainly in neurons of layer 13. The GluR4 subunit was only detected in a few cells of the tectal layer 13. GluR1 and GluR2/3 were observed in neurons of the nucleus geniculatus lateralis ventralis, whereas GluR4 was only present in its neuropil. Somata in the accessory optic nucleus appeared to contain GluR2/3 and GluR4, whereas GluR1 was the dominant subunit in the neuropil of this nucleus. These results suggest that different subpopulations of visual neurons might express different combinations of AMPA-type GluR subunits, which in turn might generate different synaptic responses to glutamate derived from retinal ganglion cell axons

  19. Pharmacological characterization and binding modes of novel racemic and optically active phenylalanine-based antagonists of AMPA receptors

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    Szymańska, Ewa; Nielsen, Birgitte; Johansen, Tommy Nørskov

    2017-01-01

    affinity and preference for AMPA receptors. Individual stereoisomers of selected compounds were further evaluated at recombinant homomeric rat GluA2 and GluA3 receptors. The most potent compound, (–)-2-amino-3-(6-chloro-2',5'-dihydroxy-5-nitro-[1,1'-biphenyl]-3-yl)propanoic acid, the expected R...

  20. Basal Levels of AMPA Receptor GluA1 Subunit Phosphorylation at Threonine 840 and Serine 845 in Hippocampal Neurons

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    Babiec, Walter E.; Guglietta, Ryan; O'Dell, Thomas J.

    2016-01-01

    Dephosphorylation of AMPA receptor (AMPAR) GluA1 subunits at two sites, serine 845 (S845) and threonine 840 (T840), is thought to be involved in NMDA receptor-dependent forms of long-term depression (LTD). Importantly, the notion that dephosphorylation of these sites contributes to LTD assumes that a significant fraction of GluA1 subunits are…

  1. (S)-homo-AMPA, a specific agonist at the mGlu6 subtype of metabotropic glutamic acid receptors

    DEFF Research Database (Denmark)

    Ahmadian, H; Nielsen, B; Bräuner-Osborne, Hans

    1997-01-01

    of the spectroscopic configurational assignments. The activities of 6 and 7 at ionotropic EAA (iGlu) receptors and at mGlu1-7 were studied. (S)-Homo-AMPA (6) was shown to be a specific agonist at mGlu6 (EC50 = 58 +/- 11 microM) comparable in potency with the endogenous mGlu agonist (S)-glutamic acid (EC50 = 20 +/- 3......Our previous publication (J. Med. Chem. 1996, 39, 3188-3194) described (RS)-2-amino-4-(3-hydroxy-5-methylisoxazol-4-yl)butyric acid (Homo-AMPA) as a highly selective agonist at the mGlu6 subtype of metabotropic excitatory amino acid (EAA) receptors. Homo-AMPA has already become a standard agonist...... microM). Although Homo-AMPA did not show significant effects at iGlu receptors, (R)-Homo-AMPA (7), which was inactive at mGlu1-7, turned out to be a weak N-methyl-D-aspartic acid (NMDA) receptor antagonist (IC50 = 131 +/- 18 microM)....

  2. Translational PK-PD modelling of molecular target modulation for the AMPA receptor positive allosteric modulator Org 26576.

    Science.gov (United States)

    Bursi, Roberta; Erdemli, Gul; Campbell, Robert; Hutmacher, Matthew M; Kerbusch, Thomas; Spanswick, David; Jeggo, Ross; Nations, Kari R; Dogterom, Peter; Schipper, Jacques; Shahid, Mohammed

    2011-12-01

    The α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor potentiator Org 26576 represents an interesting pharmacological tool to evaluate the utility of glutamatergic enhancement towards the treatment of psychiatric disorders. In this study, a rat-human translational pharmacokinetic-pharmacodynamic (PK-PD) model of AMPA receptor modulation was used to predict human target engagement and inform dose selection in efficacy clinical trials. Modelling and simulation was applied to rat plasma and cerebrospinal fluid (CSF) pharmacokinetic and pharmacodynamic measurements to identify a target concentration (EC(80)) for AMPA receptor modulation. Human plasma pharmacokinetics was determined from 33 healthy volunteers and eight major depressive disorder patients. From four out of these eight patients, CSF PK was also determined. Simulations of human CSF levels were performed for several doses of Org 26576. Org 26576 (0.1-10 mg/kg, i.v.) potentiated rat hippocampal AMPA receptor responses in an exposure-dependant manner. The rat plasma and CSF PK data were fitted by one-compartment model each. The rat CSF PK-PD model yielded an EC(80) value of 593 ng/ml (90% confidence interval 406.8, 1,264.1). The human plasma and CSF PK data were simultaneously well described by a two-compartment model. Simulations showed that in humans at 100 mg QD, CSF levels of Org 26576 would exceed the EC(80) target concentration for about 2 h and that 400 mg BID would engage AMPA receptors for 24 h. The modelling approach provided useful insight on the likely human dose-molecular target engagement relationship for Org 26576. Based on the current analysis, 100 and 400 mg BID would be suitable to provide 'phasic' and 'continuous' AMPA receptor engagement, respectively.

  3. Importance of GluA1 subunit-containing AMPA glutamate receptors for morphine state-dependency.

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    Teemu Aitta-aho

    Full Text Available In state-dependency, information retrieval is most efficient when the animal is in the same state as it was during the information acquisition. State-dependency has been implicated in a variety of learning and memory processes, but its mechanisms remain to be resolved. Here, mice deficient in AMPA-type glutamate receptor GluA1 subunits were first conditioned to morphine (10 or 20 mg/kg s.c. during eight sessions over four days using an unbiased procedure, followed by testing for conditioned place preference at morphine states that were the same as or different from the one the mice were conditioned to. In GluA1 wildtype littermate mice the same-state morphine dose produced the greatest expression of place preference, while in the knockout mice no place preference was then detected. Both wildtype and knockout mice expressed moderate morphine-induced place preference when not at the morphine state (saline treatment at the test; in this case, place preference was weaker than that in the same-state test in wildtype mice. No correlation between place preference scores and locomotor activity during testing was found. Additionally, as compared to the controls, the knockout mice showed unchanged sensitization to morphine, morphine drug discrimination and brain regional μ-opioid receptor signal transduction at the G-protein level. However, the knockout mice failed to show increased AMPA/NMDA receptor current ratios in the ventral tegmental area dopamine neurons of midbrain slices after a single injection of morphine (10 mg/kg, s.c., sliced prepared 24 h afterwards, in contrast to the wildtype mice. The results indicate impaired drug-induced state-dependency in GluA1 knockout mice, correlating with impaired opioid-induced glutamate receptor neuroplasticity.

  4. Group III mGlu receptor agonists potentiate the anticonvulsant effect of AMPA and NMDA receptor block.

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    De Sarro, Giovambattista; Chimirri, Alba; Meldrum, Brian S

    2002-09-06

    We report the anticonvulsant action in DBA/2 mice of two mGlu Group III receptor agonists: (R,S)-4-phosphonophenylglycine, (R,S)-PPG, a compound with moderate mGlu8 selectivity, and of (1S,3R,4S)-1-aminocyclopentane-1,2,4-tricarboxylic acid, ACPT-1, a selective agonist for mGlu4alpha receptors. Both compounds, given intracerebroventricularly at doses which did not show marked anticonvulsant activity, produced a consistent shift to the left of the dose-response curves (i.e. enhanced the anticonvulsant properties) of 1-(4'-aminophenyl)-3,5-dihydro-7,8-dimethoxy-4H-2,3-benzodiazepin-4-one hydrochloride, CFM-2, a noncompetitive AMPA receptor antagonist, and 3-((+/-)-2-carboxypiperazin-4-yl)-1-phosphonic acid, CPPene, a competitive NMDA receptor antagonist, in DBA/2 mice. In addition, (R,S)-PPG and ACPT-1 administered intracerebroventricularly prolonged the time course of the anticonvulsant properties of CFM-2 (33 micromol/kg, i.p.) and CPPene (3.3 micromol/kg, i.p.) administered intraperitoneally. We conclude that modest reduction of synaptic glutamate release by activation of Group III metabotropic receptors potentiates the anticonvulsant effect of AMPA and NMDA receptor blockade. Copyright 2002 Elsevier Science B.V.

  5. Odor Preference Learning and Memory Modify GluA1 Phosphorylation and GluA1 Distribution in the Neonate Rat Olfactory Bulb: Testing the AMPA Receptor Hypothesis in an Appetitive Learning Model

    Science.gov (United States)

    Cui, Wen; Darby-King, Andrea; Grimes, Matthew T.; Howland, John G.; Wang, Yu Tian; McLean, John H.; Harley, Carolyn W.

    2011-01-01

    An increase in synaptic AMPA receptors is hypothesized to mediate learning and memory. AMPA receptor increases have been reported in aversive learning models, although it is not clear if they are seen with memory maintenance. Here we examine AMPA receptor changes in a cAMP/PKA/CREB-dependent appetitive learning model: odor preference learning in…

  6. Agmatine produces antidepressant-like effects by activating AMPA receptors and mTOR signaling.

    Science.gov (United States)

    Neis, Vivian Binder; Moretti, Morgana; Bettio, Luis Eduardo B; Ribeiro, Camille M; Rosa, Priscila Batista; Gonçalves, Filipe Marques; Lopes, Mark William; Leal, Rodrigo Bainy; Rodrigues, Ana Lúcia S

    2016-06-01

    The activation of AMPA receptors and mTOR signaling has been reported as mechanisms underlying the antidepressant effects of fast-acting agents, specially the NMDA receptor antagonist ketamine. In the present study, oral administration of agmatine (0.1mg/kg), a neuromodulator that has been reported to modulate NMDA receptors, caused a significant reduction in the immobility time of mice submitted to the tail suspension test (TST), an effect prevented by the administration of DNQX (AMPA receptor antagonist, 2.5μg/site, i.c.v.), BDNF antibody (1μg/site, i.c.v.), K-252a (TrkB receptor antagonist, 1μg/site, i.c.v.), LY294002 (PI3K inhibitor, 10nmol/site, i.c.v.) or rapamycin (selective mTOR inhibitor, 0.2nmol/site, i.c.v.). Moreover, the administration of lithium chloride (non-selective GSK-3β inhibitor, 10mg/kg, p.o.) or AR-A014418 (selective GSK-3β inhibitor, 0.01μg/site, i.c.v.) in combination with a sub-effective dose of agmatine (0.0001mg/kg, p.o.) reduced the immobility time in the TST when compared with either drug alone. Furthermore, increased immunocontents of BDNF, PSD-95 and GluA1 were found in the prefrontal cortex of mice just 1h after agmatine administration. These results indicate that the antidepressant-like effect of agmatine in the TST may be dependent on the activation of AMPA and TrkB receptors, PI3K and mTOR signaling as well as inhibition of GSK-3β, and increase in synaptic proteins. The results contribute to elucidate the complex signaling pathways involved in the antidepressant effect of agmatine and reinforce the pivotal role of these molecular targets for antidepressant responses. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  7. Dual Effects of TARP γ-2 on Glutamate Efficacy Can Account for AMPA Receptor Autoinactivation

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    Ian D. Coombs

    2017-08-01

    Full Text Available Fast excitatory transmission in the CNS is mediated mainly by AMPA-type glutamate receptors (AMPARs associated with transmembrane AMPAR regulatory proteins (TARPs. At the high glutamate concentrations typically seen during synaptic transmission, TARPs slow receptor desensitization and enhance mean channel conductance. However, their influence on channels gated by low glutamate concentrations, as encountered during delayed transmitter clearance or synaptic spillover, is poorly understood. We report here that TARP γ-2 reduces the ability of low glutamate concentrations to cause AMPAR desensitization and enhances channel gating at low glutamate occupancy. Simulations show that, by shifting the balance between AMPAR activation and desensitization, TARPs can markedly facilitate the transduction of spillover-mediated synaptic signaling. Furthermore, the dual effects of TARPs can account for biphasic steady-state glutamate concentration-response curves—a phenomenon termed “autoinactivation,” previously thought to reflect desensitization-mediated AMPAR/TARP dissociation.

  8. Deletion of the GluA1 AMPA Receptor Subunit Alters the Expression of Short-Term Memory

    Science.gov (United States)

    Sanderson, David J.; Sprengel, Rolf; Seeburg, Peter H.; Bannerman, David M.

    2011-01-01

    Deletion of the GluA1 AMPA receptor subunit selectively impairs short-term memory for spatial locations. We further investigated this deficit by examining memory for discrete nonspatial visual stimuli in an operant chamber. Unconditioned suppression of magazine responding to visual stimuli was measured in wild-type and GluA1 knockout mice.…

  9. Glutamate AMPA/kainate receptors, not GABA(A) receptors, mediate estradiol-induced sex differences in the hypothalamus.

    Science.gov (United States)

    Todd, Brigitte J; Schwarz, Jaclyn M; Mong, Jessica A; McCarthy, Margaret M

    2007-02-15

    Sex differences in brain morphology underlie physiological and behavioral differences between males and females. During the critical perinatal period for sexual differentiation in the rat, gonadal steroids act in a regionally specific manner to alter neuronal morphology. Using Golgi-Cox impregnation, we examined several parameters of neuronal morphology in postnatal day 2 (PN2) rats. We found that in the ventromedial nucleus of the hypothalamus (VMN) and in areas just dorsal and just lateral to the VMN that there was a sex difference in total dendritic spine number (males greater) that was abolished by treating female neonates with exogenous testosterone. Dendritic branching was similarly sexually differentiated and hormonally modulated in the VMN and dorsal to the VMN. We then used spinophilin, a protein that positively correlates with the amount of dendritic spines, to investigate the mechanisms underlying these sex differences. Estradiol, which mediates most aspects of masculinization and is the aromatized product of testosterone, increased spinophilin levels in female PN2 rats to that of males. Muscimol, an agonist at GABA(A) receptors, did not affect spinophilin protein levels in either male or female neonates. Kainic acid, an agonist at glutamatergic AMPA/kainate receptors, mimicked the effect of estradiol in females. Antagonizing AMPA/kainate receptors with NBQX prevented the estradiol-induced increase in spinophilin in females but did not affect spinophilin level in males. (c) 2007 Wiley Periodicals, Inc.

  10. M1 muscarinic receptor facilitates cognitive function by interplay with AMPA receptor GluA1 subunit.

    Science.gov (United States)

    Zhao, Lan-Xue; Ge, Yan-Hui; Xiong, Cai-Hong; Tang, Ling; Yan, Ying-Hui; Law, Ping-Yee; Qiu, Yu; Chen, Hong-Zhuan

    2018-03-06

    M1 muscarinic acetylcholine receptors (M1 mAChRs) are the most abundant muscarinic receptors in the hippocampus and have been shown to have procognitive effects. AMPA receptors (AMPARs), an important subtype of ionotropic glutamate receptors, are key components in neurocognitive networks. However, the role of AMPARs in procognitive effects of M1 mAChRs and how M1 mAChRs affect the function of AMPARs remain poorly understood. Here, we found that basal expression of GluA1, a subunit of AMPARs, and its phosphorylation at Ser845 were maintained by M1 mAChR activity. Activation of M1 mAChRs promoted membrane insertion of GluA1, especially to postsynaptic densities. Impairment of hippocampus-dependent learning and memory by antagonism of M1 mAChRs paralleled the reduction of GluA1 expression, and improvement of learning and memory by activation of M1 mAChRs was accompanied by the synaptic insertion of GluA1 and its increased phosphorylation at Ser845. Furthermore, abrogation of phosphorylation of Ser845 residue of GluA1 ablated M1 mAChR-mediated improvement of learning and memory. Taken together, these results show a functional correlation of M1 mAChRs and GluA1 and the essential role of GluA1 in M1 mAChR-mediated cognitive improvement.-Zhao, L.-X., Ge, Y.-H., Xiong, C.-H., Tang, L., Yan, Y.-H., Law, P.-Y., Qiu, Y., Chen, H.-Z. M1 muscarinic receptor facilitates cognitive function by interplay with AMPA receptor GluA1 subunit.

  11. Synthesis and in vitro pharmacology at AMPA and kainate preferring glutamate receptors of 4-heteroarylmethylidene glutamate analogues

    DEFF Research Database (Denmark)

    Valgeirsson, Jon; Christensen, Jeppe K; Kristensen, Anders S

    2003-01-01

    affinity for the GluR2 subtype of AMPA receptors. As an attempt to develop new pharmacological tools for studies of GluR5 receptors, (S)-E-4-(2-thiazolylmethylene)glutamic acid (4a) was designed as a structural hybrid between 1 and 3. 4a was shown to be a potent GluR5 agonist and a high affinity ligand...

  12. Effects of the AMPA antagonist ZK 200775 on visual function: a randomized controlled trial.

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    Richard Bergholz

    Full Text Available BACKGROUND: ZK 200775 is an antagonist at the alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA receptor and had earned attention as a possible neuroprotective agent in cerebral ischemia. Probands receiving the agent within phase I trials reported on an alteration of visual perception. In this trial, the effects of ZK 200775 on the visual system were analyzed in detail. METHODOLOGY: In a randomised controlled trial we examined eyes and vision before and after the intravenous administration of two different doses of ZK 200775 and placebo. There were 3 groups of 6 probands each: Group 1 recieved 0.03 mg/kg/h, group 2 0.75 mg/kg/h of ZK 200775, the control group received 0.9% sodium chloride solution. Probands were healthy males aged between 57 and 69 years. The following methods were applied: clinical examination, visual acuity, ophthalmoscopy, colour vision, rod absolute threshold, central visual field, pattern-reversal visual evoked potentials (pVEP, ON-OFF and full-field electroretinogram (ERG. PRINCIPAL FINDINGS: No effect of ZK 200775 was seen on eye position or motility, stereopsis, pupillary function or central visual field testing. Visual acuity and dark vision deteriorated significantly in both treated groups. Color vision was most remarkably impaired. The dark-adapted ERG revealed a reduction of oscillatory potentials (OP and partly of the a- and b-wave, furthermore an alteration of b-wave morphology and an insignificantly elevated b/a-ratio. Cone-ERG modalities showed decreased amplitudes and delayed implicit times. In the ON-OFF ERG the ON-answer amplitudes increased whereas the peak times of the OFF-answer were reduced. The pattern VEP exhibited lower amplitudes and prolonged peak times. CONCLUSIONS: The AMPA receptor blockade led to a strong impairment of typical OFF-pathway functions like color vision and the cone ERG. On the other hand the ON-pathway as measured by dark vision and the scotopic ERG was affected as well

  13. Cysteine 893 is a target of regulatory thiol modifications of GluA1 AMPA receptors.

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    Lotta von Ossowski

    Full Text Available Recent studies indicate that glutamatergic signaling involves, and is regulated by, thiol modifying and redox-active compounds. In this study, we examined the role of a reactive cysteine residue, Cys-893, in the cytosolic C-terminal tail of GluA1 AMPA receptor as a potential regulatory target. Elimination of the thiol function by substitution of serine for Cys-893 led to increased steady-state expression level and strongly reduced interaction with SAP97, a major cytosolic interaction partner of GluA1 C-terminus. Moreover, we found that of the three cysteine residues in GluA1 C-terminal tail, Cys-893 is the predominant target for S-nitrosylation induced by exogenous nitric oxide donors in cultured cells and lysates. Co-precipitation experiments provided evidence for native association of SAP97 with neuronal nitric oxide synthase (nNOS and for the potential coupling of Ca2+-permeable GluA1 receptors with nNOS via SAP97. Our results show that Cys-893 can serve as a molecular target for regulatory thiol modifications of GluA1 receptors, including the effects of nitric oxide.

  14. Ketamine and ketamine metabolites as novel estrogen receptor ligands: Induction of cytochrome P450 and AMPA glutamate receptor gene expression.

    Science.gov (United States)

    Ho, Ming-Fen; Correia, Cristina; Ingle, James N; Kaddurah-Daouk, Rima; Wang, Liewei; Kaufmann, Scott H; Weinshilboum, Richard M

    2018-04-03

    Major depressive disorder (MDD) is the most common psychiatric illness worldwide, and it displays a striking sex-dependent difference in incidence, with two thirds of MDD patients being women. Ketamine treatment can produce rapid antidepressant effects in MDD patients, effects that are mediated-at least partially-through glutamatergic neurotransmission. Two active metabolites of ketamine, (2R,6R)-hydroxynorketamine (HNK) and (2S,6S)-HNK, also appear to play a key role in ketamine's rapid antidepressant effects through the activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors. In the present study, we demonstrated that estrogen plus ketamine or estrogen plus active ketamine metabolites displayed additive effects on the induction of the expression of AMPA receptor subunits. In parallel, the expression of estrogen receptor alpha (ERα) was also significantly upregulated. Even more striking, radioligand binding assays demonstrated that [ 3 H]-ketamine can directly bind to ERα (K D : 344.5 ± 13 nM). Furthermore, ketamine and its (2R,6R)-HNK and (2S,6S)-HNK metabolites displayed similar affinity for ERα (IC 50 : 2.31 ± 0.1, 3.40 ± 0.2, and 3.53 ± 0.2 µM, respectively) as determined by [ 3 H]-ketamine displacement assays. Finally, induction of AMPA receptors by either estrogens or ketamine and its metabolites was lost when ERα was knocked down or silenced pharmacologically. These results suggest a positive feedback loop by which estrogens can augment the effects of ketamine and its (2R,6R)-HNK and (2S,6S)-HNK metabolites on the ERα-induced transcription of CYP2A6 and CYP2B6, estrogen inducible enzymes that catalyze ketamine's biotransformation to form the two active metabolites. These observations provide novel insight into ketamine's molecular mechanism(s) of action and have potential implications for the treatment of MDD. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Impaired associative fear learning in mice with complete loss or haploinsufficiency of AMPA GluR1 receptors

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    Michael Feyder

    2007-12-01

    Full Text Available There is compelling evidence that L-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA glutamate receptors containing the GluR1 subunit contribute to the molecular mechanisms associated with learning. AMPA GluR1 glutamate receptor knockout mice (KO exhibit abnormal hippocampal and amygdala plasticity, and deficits on various assays for cognition including Pavlovian fear conditioning. Here we examined associative fear learning in mice with complete absence (KO or partial loss (heterozygous mutant, HET of GluR1 on multiple fear conditioning paradigms. After multi-trial delay or trace conditioning, KO displayed impaired tone and context fear recall relative to WT, whereas HET were normal. After one-trial delay conditioning, both KO and HET showed impaired tone and context recall. HET and KO showed normal nociceptive sensitivity in the hot plate and tail flick tests. These data demonstrate that the complete absence of GluR1 subunit-containing receptors prevents the formation of associative fear memories, while GluR1 haploinsufficiency is sufficient to impair one-trial fear learning. These findings support growing evidence of a major role for GluR1-containing AMPA receptors in amygdalamediated forms of learning and memory.

  16. Ketamine-induced inhibition of glycogen synthase kinase-3 contributes to the augmentation of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor signaling.

    Science.gov (United States)

    Beurel, Eléonore; Grieco, Steven F; Amadei, Celeste; Downey, Kimberlee; Jope, Richard S

    2016-09-01

    Sub-anesthetic doses of ketamine have been found to provide rapid antidepressant actions, indicating that the cellular signaling systems targeted by ketamine are potential sites for therapeutic intervention. Ketamine acts as an antagonist of N-methyl-D-aspartate (NMDA) receptors, and animal studies indicate that subsequent augmentation of signaling by α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors is critical for the antidepressant outcome. In this study, we tested if the inhibitory effect of ketamine on glycogen synthase kinase-3 (GSK3) affected hippocampal cell-surface AMPA receptors using immunoblotting of membrane and synaptosomal extracts from wild-type and GSK3 knockin mice. Treatment with an antidepressant dose of ketamine increased the hippocampal membrane level of the AMPA glutamate receptor (GluA)1 subunit, but did not alter the localization of GluA2, GluA3, or GluA4. This effect of ketamine was abrogated in GSK3 knockin mice expressing mutant GSK3 that cannot be inhibited by ketamine, demonstrating that ketamine-induced inhibition of GSK3 is necessary for up-regulation of cell surface AMPA GluA1 subunits. AMPA receptor trafficking is regulated by post-synaptic density-95 (PSD-95), a substrate for GSK3. Ketamine treatment decreased the hippocampal membrane level of phosphorylated PSD-95 on Thr-19, the target of GSK3 that promotes AMPA receptor internalization. These results demonstrate that ketamine-induced inhibition of GSK3 causes reduced phosphorylation of PSD-95, diminishing the internalization of AMPA GluA1 subunits to allow for augmented signaling through AMPA receptors following ketamine treatment. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Memory, Plasticity and Sleep - A role for calcium permeable AMPA receptors?

    Directory of Open Access Journals (Sweden)

    Jason D Shepherd

    2012-04-01

    Full Text Available Experience shapes and molds the brain throughout life. These changes in neuronal circuits are produced by a myriad of molecular and cellular processes. Simplistically, circuits are modified through changes in neurotransmitter release or through neurotransmitter detection at synapses. The predominant neurotransmitter receptor in excitatory transmission, the AMPA-type glutamate receptor, is exquisitely sensitive to changes in experience and synaptic activity. These ion channels are usually impermeable to calcium, a property conferred by the GluA2 subunit. However, GluA2-lacking AMPARs are permeable to calcium and have recently been shown to play a unique role in synaptic function. In this review, I will describe new findings on the role of calcium permeable AMPARs (CP-AMPARs in experience-dependent and synaptic plasticity. These studies suggest that CP-AMPARs play a prominent role in maintaining circuits in a labile state where further plasticity can occur, thus promoting metaplasticity. Moreover, the abnormal expression of CP-AMPARs has been implicated in drug addiction and memory disorders and thus may be a novel therapeutic target.

  18. Synaptic Changes in AMPA Receptor Subunit Expression in Cortical Parvalbumin Interneurons in the Stargazer Model of Absence Epilepsy

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    Nadia K. Adotevi

    2017-12-01

    Full Text Available Feedforward inhibition is essential to prevent run away excitation within the brain. Recent evidence suggests that a loss of feed-forward inhibition in the corticothalamocortical circuitry may underlie some absence seizures. However, it is unclear if this aberration is specifically linked to loss of synaptic excitation onto local fast-spiking parvalbumin-containing (PV+ inhibitory interneurons, which are responsible for mediating feedforward inhibition within cortical networks. We recently reported a global tissue loss of AMPA receptors (AMPARs, and a specific mistrafficking of these AMPARs in PV+ interneurons in the stargazer somatosensory cortex. The current study was aimed at investigating if cellular changes in AMPAR expression were translated into deficits in receptors at specific synapses in the feedforward inhibitory microcircuit. Using western blot immunolabeling on biochemically isolated synaptic fractions, we demonstrate a loss of AMPAR GluA1–4 subunits in the somatosensory cortex of stargazers compared to non-epileptic control mice. Furthermore, using double post-embedding immunogold-cytochemistry, we show a loss of GluA1–4-AMPARs at excitatory synapses onto cortical PV+ interneurons. Altogether, these data indicate a loss of synaptic AMPAR-mediated excitation of cortical PV+ inhibitory neurons. As the cortex is considered the site of initiation of spike wave discharges (SWDs within the corticothalamocortical circuitry, loss of AMPARs at cortical PV+ interneurons likely impairs feed-forward inhibitory output, and contributes to the generation of SWDs and absence seizures in stargazers.

  19. Plasticity of calcium-permeable AMPA glutamate receptors in Pro-opiomelanocortin neurons.

    Science.gov (United States)

    Suyama, Shigetomo; Ralevski, Alexandra; Liu, Zhong-Wu; Dietrich, Marcelo O; Yada, Toshihiko; Simonds, Stephanie E; Cowley, Michael A; Gao, Xiao-Bing; Diano, Sabrina; Horvath, Tamas L

    2017-08-01

    POMC neurons integrate metabolic signals from the periphery. Here, we show in mice that food deprivation induces a linear current-voltage relationship of AMPAR-mediated excitatory postsynaptic currents (EPSCs) in POMC neurons. Inhibition of EPSCs by IEM-1460, an antagonist of calcium-permeable (Cp) AMPARs, diminished EPSC amplitude in the fed but not in the fasted state, suggesting entry of GluR2 subunits into the AMPA receptor complex during food deprivation. Accordingly, removal of extracellular calcium from ACSF decreased the amplitude of mEPSCs in the fed but not the fasted state. Ten days of high-fat diet exposure, which was accompanied by elevated leptin levels and increased POMC neuronal activity, resulted in increased expression of Cp-AMPARs on POMC neurons. Altogether, our results show that entry of calcium via Cp-AMPARs is inherent to activation of POMC neurons, which may underlie a vulnerability of these neurons to calcium overload while activated in a sustained manner during over-nutrition.

  20. BDNF and AMPA receptors in the cNTS modulate the hyperglycemic reflex after local carotid body NaCN stimulation.

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    Cuéllar, R; Montero, S; Luquín, S; García-Estrada, J; Melnikov, V; Virgen-Ortiz, A; Lemus, M; Pineda-Lemus, M; de Álvarez-Buylla, E

    2017-07-01

    The application of sodium cyanide (NaCN) to the carotid body receptors (CBR) (CBR stimulation) induces rapid blood hyperglycemia and an increase in brain glucose retention. The commissural nucleus tractus solitarius (cNTS) is an essential relay nucleus in this hyperglycemic reflex; it receives glutamatergic afferents (that also release brain derived neurotrophic factor, BDNF) from the nodose-petrosal ganglia that relays CBR information. Previous work showed that AMPA in NTS blocks hyperglycemia and brain glucose retention after CBR stimulation. In contrast, BDNF, which attenuates glutamatergic AMPA currents in NTS, enhances these glycemic responses. Here we investigated the combined effects of BDNF and AMPA (and their antagonists) in NTS on the glycemic responses to CBR stimulation. Microinjections of BDNF plus AMPA into the cNTS before CBR stimulation in anesthetized rats, induced blood hyperglycemia and an increase in brain arteriovenous (a-v) of blood glucose concentration difference, which we infer is due to increased brain glucose retention. By contrast, the microinjection of the TrkB antagonist K252a plus AMPA abolished the glycemic responses to CBR stimulation similar to what is observed after AMPA pretreatments. In BDNF plus AMPA microinjections preceding CBR stimulation, the number of c-fos immunoreactive cNTS neurons increased. In contrast, in the rats microinjected with K252a plus AMPA in NTS, before CBR stimulation, c-fos expression in cNTS decreased. The expression of AMPA receptors GluR2/3 did not change in any of the studied groups. These results indicate that BDNF in cNTS plays a key role in the modulation of the hyperglycemic reflex initiated by CBR stimulation. Copyright © 2017. Published by Elsevier B.V.

  1. Differential expression of AMPA-type glutamate receptor subunits during development of the chick optic tectum

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    Batista S.S.

    2002-01-01

    Full Text Available Glutamate receptors have been often associated with developmental processes. We used immunohistochemical techniques to evaluate the expression of the AMPA-type glutamate receptor (GluR subunits in the chick optic tectum (TeO. Chick embryos from the 5th through the 20th embryonic day (E5-E20 and one-day-old (P1 chicks were used. The three types of immunoreactivity evaluated (GluR1, GluR2/3, and GluR4 had different temporal and spatial expression patterns in the several layers of the TeO. The GluR1 subunit first appeared as moderate staining on E7 and then increased on E9. The mature GluR1 pattern included intense staining only in layer 5 of the TeO. The GluR2/3 subunits presented low expression on E5, which became intense on E7. The staining for GluR2/3 changed to very intense on E14 in tectal layer 13. Staining of layer 13 neurons is the most prominent feature of GluR immunoreactivity in the adult TeO. The GluR4 subunit generally presented the lowest expression starting on E7, which was similar to the adult pattern. Some instances of transient expression of GluR subunits were observed in specific cell populations from E9 through E20. These results demonstrate a differential expression of the GluR subunits in the embryonic TeO, adding information about their possible functions in the developmental processes of the visual system.

  2. AMPA/kainate glutamate receptors contribute to inflammation, degeneration and pain related behaviour in inflammatory stages of arthritis

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    Bonnet, Cleo S; Williams, Anwen S; Gilbert, Sophie J; Harvey, Ann K; Evans, Bronwen A; Mason, Deborah J

    2015-01-01

    Objectives Synovial fluid glutamate concentrations increase in arthritis. Activation of kainate (KA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors (GluRs) increase interleukin-6 (IL-6) release and cause arthritic pain, respectively. We hypothesised that AMPA and KA GluRs are expressed in human arthritis, and that intra-articular NBQX (AMPA/KA GluR antagonist) prevents pain and pathology in antigen-induced arthritis (AIA). Methods GluR immunohistochemistry was related to synovial inflammation and degradation in osteoarthritis (OA) and rheumatoid arthritis (RA). A single intra-articular NBQX injection was given at induction, and knee swelling and gait of AIA and AIA+NBQX rats compared over 21 days, before imaging, RT-qPCR, histology and immunohistochemistry of joints. Effects of NBQX on human primary osteoblast (HOB) activity were determined. Results AMPAR2 and KA1 immunolocalised to remodelling bone, cartilage and synovial cells in human OA and RA, and rat AIA. All arthritic tissues showed degradation and synovial inflammation. NBQX reduced GluR abundance, knee swelling (parthritis. PMID:24130267

  3. Drug-driven AMPA receptor redistribution mimicked by selective dopamine neuron stimulation.

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    Matthew T C Brown

    2010-12-01

    Full Text Available Addictive drugs have in common that they cause surges in dopamine (DA concentration in the mesolimbic reward system and elicit synaptic plasticity in DA neurons of the ventral tegmental area (VTA. Cocaine for example drives insertion of GluA2-lacking AMPA receptors (AMPARs at glutamatergic synapes in DA neurons. However it remains elusive which molecular target of cocaine drives such AMPAR redistribution and whether other addictive drugs (morphine and nicotine cause similar changes through their effects on the mesolimbic DA system.We used in vitro electrophysiological techniques in wild-type and transgenic mice to observe the modulation of excitatory inputs onto DA neurons by addictive drugs. To observe AMPAR redistribution, post-embedding immunohistochemistry for GluA2 AMPAR subunit was combined with electron microscopy. We also used a double-floxed AAV virus expressing channelrhodopsin together with a DAT Cre mouse line to selectively express ChR2 in VTA DA neurons. We find that in mice where the effect of cocaine on the dopamine transporter (DAT is specifically blocked, AMPAR redistribution was absent following administration of the drug. Furthermore, addictive drugs known to increase dopamine levels cause a similar AMPAR redistribution. Finally, activating DA VTA neurons optogenetically is sufficient to drive insertion of GluA2-lacking AMPARs, mimicking the changes observed after a single injection of morphine, nicotine or cocaine.We propose the mesolimbic dopamine system as a point of convergence at which addictive drugs can alter neural circuits. We also show that direct activation of DA neurons is sufficient to drive AMPAR redistribution, which may be a mechanism associated with early steps of non-substance related addictions.

  4. Hippocampal GluA1-containing AMPA receptors mediate context-dependent sensitization to morphine.

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    Xia, Yan; Portugal, George S; Fakira, Amanda K; Melyan, Zara; Neve, Rachael; Lee, H Thomas; Russo, Scott J; Liu, Jie; Morón, Jose A

    2011-11-09

    Glutamatergic systems, including AMPA receptors (AMPARs), are involved in opiate-induced neuronal and behavioral plasticity, although the mechanisms underlying these effects are not fully understood. In the present study, we investigated the effects of repeated morphine administration on AMPAR expression, synaptic plasticity, and context-dependent behavioral sensitization to morphine. We found that morphine treatment produced changes of synaptic AMPAR expression in the hippocampus, a brain area that is critically involved in learning and memory. These changes could be observed 1 week after the treatment, but only when mice developed context-dependent behavioral sensitization to morphine in which morphine treatment was associated with drug administration environment. Context-dependent behavioral sensitization to morphine was also associated with increased basal synaptic transmission and disrupted hippocampal long-term potentiation (LTP), whereas these effects were less robust when morphine administration was not paired with the drug administration environment. Interestingly, some effects may be related to the prior history of morphine exposure in the drug-associated environment, since alterations of AMPAR expression, basal synaptic transmission, and LTP were observed in mice that received a saline challenge 1 week after discontinuation of morphine treatment. Furthermore, we demonstrated that phosphorylation of GluA1 AMPAR subunit plays a critical role in the acquisition and expression of context-dependent behavioral sensitization, as this behavior is blocked by a viral vector that disrupts GluA1 phosphorylation. These data provide evidence that glutamatergic signaling in the hippocampus plays an important role in context-dependent sensitization to morphine and supports further investigation of glutamate-based strategies for treating opiate addiction.

  5. Different AMPA receptor subtypes mediate the distinct kinetic components of a biphasic EPSC in hippocampal interneurons

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    Todd eStincic

    2015-05-01

    Full Text Available CA1 hippocampal interneurons at the border between stratum radiatum and stratum lacunosum-moleculare have AMPA receptor (AMPAR-mediated excitatory postsynaptic currents (EPSCs that consist of two distinct phases: a typical fast component (FC, and a highly unusual slow component (SC that persists for hundreds of milliseconds. To determine whether these kinetically distinct components of the EPSC are mediated by distinct AMPAR subpopulations, we examined the relative contributions of GluA2-containing and –lacking AMPARs to the SC. GluA2-containing AMPARs mediated the majority of the FC whereas GluA2-lacking AMPARs preferentially generated the SC. When glutamate uptake through the glial glutamate transporter EAAT1 was inhibited, spill over-mediated AMPAR activation recruited an even slower third kinetic component that persisted for several seconds; however, this spillover-mediated current was mediated predominantly by GluA2-containing AMPARs and therefore was clearly distinct from the SC when uptake is intact. Thus, different AMPAR subpopulations that vary in GluA2 content mediate the distinct components of the AMPAR EPSC. The SC is developmentally downregulated in mice, declining after the second postnatal week. This downregulation affects both GluA2-containing and GluA2-lacking AMPARs mediating the SC, and is not accompanied by developmental changes in the GluA2 content of AMPARs underlying the FC. Thus, the downregulation of the SC appears to be independent of synaptic GluA2 expression, suggesting the involvement of another AMPAR subunit or an auxiliary protein. Our results therefore identify GluA2-dependent and GluA2-independent determinants of the SC: GluA2-lacking AMPARs preferentially contribute to the SC, while the developmental downregulation of the SC is independent of GluA2 content.

  6. Activation of PPARγ Ameliorates Spatial Cognitive Deficits through Restoring Expression of AMPA Receptors in Seipin Knock-Out Mice.

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    Zhou, Libin; Chen, Tingting; Li, Guoxi; Wu, Chaoming; Wang, Conghui; Li, Lin; Sha, Sha; Chen, Lei; Liu, George; Chen, Ling

    2016-01-27

    A characteristic phenotype of congenital generalized lipodystrophy 2 (CGL2) that is caused by loss-of-function of seipin gene is mental retardation. Here, we show that seipin deficiency in hippocampal CA1 pyramidal cells caused the reduction of peroxisome proliferator-activated receptor gamma (PPARγ). Twelve-week-old systemic seipin knock-out mice and neuronal seipin knock-out (seipin-nKO) mice, but not adipose seipin knock-out mice, exhibited spatial cognitive deficits as assessed by the Morris water maze and Y-maze, which were ameliorated by the treatment with the PPARγ agonist rosiglitazone (rosi). In addition, seipin-nKO mice showed the synaptic dysfunction and the impairment of NMDA receptor-dependent LTP in hippocampal CA1 regions. The density of AMPA-induced current (IAMPA) in CA1 pyramidal cells and GluR1/GluR2 expression were significantly reduced in seipin-nKO mice, whereas the NMDA-induced current (INMDA) and NR1/NR2 expression were not altered. Rosi treatment in seipin-nKO mice could correct the decrease in expression and activity of AMPA receptor (AMPAR) and was accompanied by recovered synaptic function and LTP induction. Furthermore, hippocampal ERK2 and CREB phosphorylation in seipin-nKO mice were reduced and this could be rescued by rosi treatment. Rosi treatment in seipin-nKO mice elevated BDNF concentration. The MEK inhibitor U0126 blocked rosi-restored AMPAR expression and LTP induction in seipin-nKO mice, but the Trk family inhibitor K252a did not. These findings indicate that the neuronal seipin deficiency selectively suppresses AMPAR expression through reducing ERK-CREB activities, leading to the impairment of LTP and spatial memory, which can be rescued by PPARγ activation. Congenital generalized lipodystrophy 2 (CGL2), caused by loss-of-function mutation of seipin gene, is characterized by mental retardation. By the generation of systemic or neuronal seipin knock-out mice, the present study provides in vivo evidence that neuronal seipin

  7. Deletion of the GluA1 AMPA receptor subunit impairs recency-dependent object recognition memory

    Science.gov (United States)

    Sanderson, David J.; Hindley, Emma; Smeaton, Emily; Denny, Nick; Taylor, Amy; Barkus, Chris; Sprengel, Rolf; Seeburg, Peter H.; Bannerman, David M.

    2011-01-01

    Deletion of the GluA1 AMPA receptor subunit impairs short-term spatial recognition memory. It has been suggested that short-term recognition depends upon memory caused by the recent presentation of a stimulus that is independent of contextual–retrieval processes. The aim of the present set of experiments was to test whether the role of GluA1 extends to nonspatial recognition memory. Wild-type and GluA1 knockout mice were tested on the standard object recognition task and a context-independent recognition task that required recency-dependent memory. In a first set of experiments it was found that GluA1 deletion failed to impair performance on either of the object recognition or recency-dependent tasks. However, GluA1 knockout mice displayed increased levels of exploration of the objects in both the sample and test phases compared to controls. In contrast, when the time that GluA1 knockout mice spent exploring the objects was yoked to control mice during the sample phase, it was found that GluA1 deletion now impaired performance on both the object recognition and the recency-dependent tasks. GluA1 deletion failed to impair performance on a context-dependent recognition task regardless of whether object exposure in knockout mice was yoked to controls or not. These results demonstrate that GluA1 is necessary for nonspatial as well as spatial recognition memory and plays an important role in recency-dependent memory processes. PMID:21378100

  8. Engineering defined membrane-embedded elements of AMPA receptor induces opposing gating modulation by cornichon 3 and stargazin.

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    Hawken, Natalie M; Zaika, Elena I; Nakagawa, Terunaga

    2017-10-15

    The AMPA-type ionotropic glutamate receptors (AMPARs) mediate the majority of excitatory synaptic transmission and their function impacts learning, cognition and behaviour. The gating of AMPARs occurs in milliseconds, precisely controlled by a variety of auxiliary subunits that are expressed differentially in the brain, but the difference in mechanisms underlying AMPAR gating modulation by auxiliary subunits remains elusive and is investigated. The elements of the AMPAR that are functionally recruited by auxiliary subunits, stargazin and cornichon 3, are located not only in the extracellular domains but also in the lipid-accessible surface of the AMPAR. We reveal that the two auxiliary subunits require a shared surface on the transmembrane domain of the AMPAR for their function, but the gating is influenced by this surface in opposing directions for each auxiliary subunit. Our results provide new insights into the mechanistic difference of AMPAR modulation by auxiliary subunits and a conceptual framework for functional engineering of the complex. During excitatory synaptic transmission, various structurally unrelated transmembrane auxiliary subunits control the function of AMPA receptors (AMPARs), but the underlying mechanisms remain unclear. We identified lipid-exposed residues in the transmembrane domain (TMD) of the GluA2 subunit of AMPARs that are critical for the function of AMPAR auxiliary subunits, stargazin (Stg) and cornichon 3 (CNIH3). These residues are essential for stabilizing the AMPAR-CNIH3 complex in detergents and overlap with the contacts made between GluA2 TMD and Stg in the cryoEM structures. Mutating these residues had opposite effects on gating modulation and complex stability when Stg- and CNIH3-bound AMPARs were compared. Specifically, in detergent the GluA2-A793F formed an unstable complex with CNIIH3 but in the membrane the GluA2-A793F-CNIH3 complex expressed a gain of function. In contrast, the GluA2-A793F-Stg complex was stable, but had

  9. Identification of an ionotropic glutamate receptor AMPA1/GRIA1 polymorphism in crossbred beef cows differing in fertility.

    Science.gov (United States)

    Cushman, R A; Miles, J R; Rempel, L A; McDaneld, T G; Kuehn, L A; Chitko-McKown, C G; Nonneman, D; Echternkamp, S E

    2013-06-01

    A proposed functional polymorphism in the ionotropic glutamate receptor AMPA1 (GRIA1) has been reported to influence antral follicle numbers and fertility in cows. Repeat breeder cows that fail to produce a calf in multiple seasons have been reported to have reduced numbers of small (1 to 3 mm) antral follicles in their ovaries. Therefore, we tested the hypothesis that this GRIA1 polymorphism was affecting antral follicle numbers in repeat breeder cows. Repeat breeder cows (n = 64) and control cows (n = 72) that had always produced a calf were housed in a dry lot and observed twice daily for behavioral estrus. Blood samples were collected, and cows were genotyped for this GRIA1 polymorphism and for a polymorphism in the GnRH receptor (GnRHR) that was proposed to influence age at puberty. On d 3 to 8 after estrus cows were slaughtered, and reproductive organs were collected to determine antral follicle count, ovary size, and uterine horn diameter. Repeat breeder cows were older at first calving than control cows (P = 0.006). The length (P = 0.03) and height (P = 0.02) of the ovary contralateral to the corpus luteum (CL) were greater in control cows than repeat breeder cows. The endometrial diameter in the horn ipsilateral to the CL was greater in the control cows than the repeat breeder cows. Repeat breeder cows had fewer small (1 to 5 mm) antral follicles than control cows (P = 0.003); however, there was no association between GRIA1 genotype and antral follicle number. The GnRHR polymorphism was associated with age at first calving because cows that were homozygous for the C allele had a greater age at first calving than heterozygous cows or cows that were homozygous for the T allele (P = 0.01). In the granulosa cells from small (1 to 5 mm) antral follicles, mRNA abundances of 2 markers of oocyte quality, anti-Müllerian hormone and pentraxin 3, did not differ between fertility groups (P ≥ 0.12). We conclude that this GRIA1 polymorphism exists in beef cows but

  10. Deficiency of Lipoprotein Lipase in Neurons Decreases AMPA Receptor Phosphorylation and Leads to Neurobehavioral Abnormalities in Mice.

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    Tian Yu

    Full Text Available Alterations in lipid metabolism have been found in several neurodegenerative disorders, including Alzheimer's disease. Lipoprotein lipase (LPL hydrolyzes triacylglycerides in lipoproteins and regulates lipid metabolism in multiple organs and tissues, including the central nervous system (CNS. Though many brain regions express LPL, the functions of this lipase in the CNS remain largely unknown. We developed mice with neuron-specific LPL deficiency that became obese on chow by 16 wks in homozygous mutant mice (NEXLPL-/- and 10 mo in heterozygous mice (NEXLPL+/-. In the present study, we show that 21 mo NEXLPL+/- mice display substantial cognitive function decline including poorer learning and memory, and increased anxiety with no difference in general motor activities and exploratory behavior. These neurobehavioral abnormalities are associated with a reduction in the 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl propanoic acid (AMPA receptor subunit GluA1 and its phosphorylation, without any alterations in amyloid β accumulation. Importantly, a marked deficit in omega-3 and omega-6 polyunsaturated fatty acids (PUFA in the hippocampus precedes the development of the neurobehavioral phenotype of NEXLPL+/- mice. And, a diet supplemented with n-3 PUFA can improve the learning and memory of NEXLPL+/- mice at both 10 mo and 21 mo of age. We interpret these findings to indicate that LPL regulates the availability of PUFA in the CNS and, this in turn, impacts the strength of synaptic plasticity in the brain of aging mice through the modification of AMPA receptor and its phosphorylation.

  11. Concurrent gradients of ribbon volume and AMPA-receptor patch volume in cochlear afferent synapses on gerbil inner hair cells.

    Science.gov (United States)

    Zhang, Lichun; Engler, Sina; Koepcke, Lena; Steenken, Friederike; Köppl, Christine

    2018-07-01

    The Mongolian gerbil is a classic animal model for age-related hearing loss. As a prerequisite for studying age-related changes, we characterized cochlear afferent synaptic morphology in young adult gerbils, using immunolabeling and quantitative analysis of confocal microscopic images. Cochlear wholemounts were triple-labeled with a hair-cell marker, a marker of presynaptic ribbons, and a marker of postsynaptic AMPA-type glutamate receptors. Seven cochlear positions covering an equivalent frequency range from 0.5 - 32 kHz were evaluated. The spatial positions of synapses were determined in a coordinate system with reference to their individual inner hair cell. Synapse numbers confirmed previous reports for gerbils (on average, 20-22 afferents per inner hair cell). The volumes of presynaptic ribbons and postsynaptic glutamate receptor patches were positively correlated: larger ribbons associated with larger receptor patches and smaller ribbons with smaller patches. Furthermore, the volumes of both presynaptic ribbons and postsynaptic receptor patches co-varied along the modiolar-pillar and the longitudinal axes of their hair cell. The gradients in ribbon volume are consistent with previous findings in cat, guinea pig, mouse and rat and further support a role in differentiating the physiological properties of type I afferents. However, the positive correlation between the volumes of pre- and postsynaptic elements in the gerbil is different to the opposing gradients found in the mouse, suggesting species-specific differences in the postsynaptic AMPA receptors that are unrelated to the fundamental classes of type I afferents. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Evidence for a Specific Integrative Mechanism for Episodic Memory Mediated by AMPA/kainate Receptors in a Circuit Involving Medial Prefrontal Cortex and Hippocampal CA3 Region.

    Science.gov (United States)

    de Souza Silva, Maria A; Huston, Joseph P; Wang, An-Li; Petri, David; Chao, Owen Yuan-Hsin

    2016-07-01

    We asked whether episodic-like memory requires neural mechanisms independent of those that mediate its component memories for "what," "when," and "where," and if neuronal connectivity between the medial prefrontal cortex (mPFC) and the hippocampus (HPC) CA3 subregion is essential for episodic-like memory. Unilateral lesion of the mPFC was combined with unilateral lesion of the CA3 in the ipsi- or contralateral hemispheres in rats. Episodic-like memory was tested using a task, which assesses the integration of memories for "what, where, and when" concomitantly. Tests for novel object recognition (what), object place (where), and temporal order memory (when) were also applied. Bilateral disconnection of the mPFC-CA3 circuit by N-methyl-d-aspartate (NMDA) lesions disrupted episodic-like memory, but left the component memories for object, place, and temporal order, per se, intact. Furthermore, unilateral NMDA lesion of the CA3 plus injection of (6-cyano-7-nitroquinoxaline-2,3-dione) (CNQX) (AMPA/kainate receptor antagonist), but not AP-5 (NMDA receptor antagonist), into the contralateral mPFC also disrupted episodic-like memory, indicating the mPFC AMPA/kainate receptors as critical for this circuit. These results argue for a selective neural system that specifically subserves episodic memory, as it is not critically involved in the control of its component memories for object, place, and time. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Selective increases of AMPA, NMDA and kainate receptor subunit mRNAs in the hippocampus and orbitofrontal cortex but not in prefrontal cortex of human alcoholics

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    Zhe eJin

    2014-01-01

    Full Text Available Glutamate is the main excitatory transmitter in the human brain. Drugs that affect the glutamatergic signaling will alter neuronal excitability. Ethanol inhibits glutamate receptors. We examined the expression level of glutamate receptor subunit mRNAs in human post-mortem samples from alcoholics and compared the results to brain samples from control subjects. RNA from hippocampal dentate gyrus (HP-DG, orbitofrontal cortex (OFC, and dorso-lateral prefrontal cortex (DL-PFC samples from 21 controls and 19 individuals with chronic alcohol dependence were included in the study. Total RNA was assayed using quantitative RT-PCR. Out of the 16 glutamate receptor subunits, mRNAs encoding two AMPA (2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-ylpropanoic acid receptor subunits GluA2 and GluA3; three kainate receptor subunits GluK2, GluK3 and GluK5 and five NMDA (N-methyl-D-aspartate receptor subunits GluN1, GluN2A, GluN2C, GluN2D and GluN3A were significantly increased in the HP-DG region in alcoholics. In the OFC, mRNA encoding the NMDA receptor subunit GluN3A was increased, whereas in the DL-PFC, no differences in mRNA levels were observed. Our laboratory has previously shown that the expression of genes encoding inhibitory GABA-A receptors is altered in the HP-DG and OFC of alcoholics (Jin et al., 2011. Whether the changes in one neurotransmitter system drives changes in the other or if they change independently is currently not known. The results demonstrate that excessive long-term alcohol consumption is associated with altered expression of genes encoding glutamate receptors in a brain region-specific manner. It is an intriguing possibility that genetic predisposition to alcoholism may contribute to these gene expression changes.

  14. Phenobarbital but not diazepam reduces AMPA/Kainate receptor mediated currents and exerts opposite actions on initial seizures in the neonatal rat hippocampus

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    Romain eNardou

    2011-07-01

    Full Text Available Diazepam (DZP and phenobarbital (PB are extensively used as first and second line drugs to treat acute seizures in neonates and their actions are thought to be mediated by increasing the actions of GABAergic signals. Yet, their efficacy is variable with occasional failure or even aggravation of recurrent seizures questioning whether other mechanisms are not involved in their actions. We have now compared the effects of DZP and PB on ictal-like events (ILEs in an in vitro model of mirror focus (MF. Using the three-compartment chamber with the two immature hippocampi and their commissural fibers placed in 3 different compartments, kainate was applied to one hippocampus and PB or DZP to the contralateral one, either after one ILE or after many recurrent ILEs that produce an epileptogenic MF. We report that in contrast to PB, DZP aggravated propagating ILEs from the start and did not prevent the formation of MF. PB reduced and DZP increased the network driven Giant Depolarising Potentials suggesting that PB may exert additional actions that are not mediated by GABA signalling. In keeping with this, PB but not DZP reduced field potentials recorded in the presence of GABA and NMDA receptor antagonists. These effects are mediated by a direct action on AMPA/Kainate receptors since PB: i reduced AMPA/Kainate receptor mediated currents induced by focal applications of glutamate ; ii reduced the amplitude and the frequency of AMPA but not NMDA receptor mediated miniature EPSCs; iii augmented the number of AMPA receptor mediated EPSCs failures evoked by minimal stimulation. These effects persisted in MF. Therefore, PB exerts its anticonvulsive actions partly by reducing AMPA/Kainate receptors mediated EPSCs in addition to the pro-GABA effects. We suggest that PB may have advantage over DZP in the treatment of initial neonatal seizures since the additional reduction of glutamate receptors mediated signals may reduce the severity of neonatal seizures.

  15. Studies on an (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist IKM-159

    DEFF Research Database (Denmark)

    Juknaite, Lina; Sugamata, Yutaro; Tokiwa, Kazuya

    2013-01-01

    IKM-159 was developed and identified as a member of a new class of heterotricyclic glutamate analogs that act as AMPA receptor-selective antagonists. However, it was not known which enantiomer of IKM-159 was responsible for its pharmacological activities. Here, we report in vivo and in vitro neur...

  16. A juvenile form of postsynaptic hippocampal long-term potentiation in mice deficient for the AMPA receptor subunit GluR-A

    NARCIS (Netherlands)

    Jensen, V.; Kaiser, K.M.M.; Borchardt, T.; Adelmann, G.; Rozov, A.; Burnashev, N.; Brix, C.; Frotscher, M.; Anderson, P.; Hvalby, O.; Sakmann, B.; Seeburg, P.H.; Sprengel, R.

    2003-01-01

    In adult mice, long-term potentiation (LTP) of synaptic transmission at CA3-to-CA1 synapses induced by tetanic stimulation requires L-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors containing GluR-A subunits. Here, we report a GluR-A-independent form of LTP, which is comparable in

  17. Odor preference learning and memory modify GluA1 phosphorylation and GluA1 distribution in the neonate rat olfactory bulb: testing the AMPA receptor hypothesis in an appetitive learning model.

    Science.gov (United States)

    Cui, Wen; Darby-King, Andrea; Grimes, Matthew T; Howland, John G; Wang, Yu Tian; McLean, John H; Harley, Carolyn W

    2011-01-01

    An increase in synaptic AMPA receptors is hypothesized to mediate learning and memory. AMPA receptor increases have been reported in aversive learning models, although it is not clear if they are seen with memory maintenance. Here we examine AMPA receptor changes in a cAMP/PKA/CREB-dependent appetitive learning model: odor preference learning in the neonate rat. Rat pups were given a single pairing of peppermint and 2 mg/kg isoproterenol, which produces a 24-h, but not a 48-h, peppermint preference in the 7-d-old rat pup. GluA1 PKA-dependent phosphorylation peaked 10 min after the 10-min training trial and returned to baseline within 90 min. At 24 h, GluA1 subunits did not change overall but were significantly increased in synaptoneurosomes, consistent with increased membrane insertion. Immunohistochemistry revealed a significant increase in GluA1 subunits in olfactory bulb glomeruli, the targets of olfactory nerve axons. Glomerular increases were seen at 3 and 24 h after odor exposure in trained pups, but not in control pups. GluA1 increases were not seen as early as 10 min after training and were no longer observed 48 h after training when odor preference is no longer expressed behaviorally. Thus, the pattern of increased GluA1 membrane expression closely follows the memory timeline. Further, blocking GluA1 insertion using an interference peptide derived from the carboxyl tail of the GluA1 subunit inhibited 24 h odor preference memory providing causative support for our hypothesis. PKA-mediated GluA1 phosphorylation and later GluA1 insertion could, conjointly, provide increased AMPA function to support both short-term and long-term appetitive memory.

  18. Characterization of the 1H-cyclopentapyrimidine-2,4(1H,3H)-dione derivative (S)-CPW399 as a novel, potent, and subtype-selective AMPA receptor full agonist with partial desensitization properties

    DEFF Research Database (Denmark)

    Campiani, G; Morelli, E; Nacci, V

    2001-01-01

    (S)-CPW399 (2b) is a novel, potent, and subtype-selective AMPA receptor full agonist that, unlike (S)-willardiine and related compounds, in mouse cerebellar granule cells, stimulated an increase in [Ca(2+)](i), and induced neuronal cell death in a time- and concentration-dependent manner. Compound...... 2b appears to be a weakly desensitizing, full agonist at AMPA receptors and therefore represents a new pharmacological tool to investigate the role of AMPA receptors in excitotoxicity and their molecular mechanisms of desensitization....

  19. Anti-AMPA-Receptor Encephalitis Presenting as a Rapid-Cycling Bipolar Disorder in a Young Woman with Turner Syndrome

    Directory of Open Access Journals (Sweden)

    Giuseppe Quaranta

    2015-01-01

    Full Text Available Background. Autoimmune encephalitis is a disorder characterised by the subacute onset of seizures, short-term memory loss, and psychiatric and behavioural symptoms. Initially, it was recognised as a paraneoplastic disorder, but recently a subgroup of patients without systemic cancer was identified. Case Description. We describe a 20-year-old woman with Turner syndrome presenting with a treatment-resistant rapid cycling bipolar disorder with cognitive impairment. She was diagnosed with anti-AMPA-receptor encephalitis. She showed marked improvement after starting memantine and valproic acid. Conclusion. This case description emphasises the importance of timely recognition of autoimmune limbic encephalitis in patients with psychiatric manifestations and a possible predisposition to autoimmune conditions, in order to rule out malignancy and to quickly initiate treatment.

  20. Integrated regulation of AMPA glutamate receptor phosphorylation in the striatum by dopamine and acetylcholine.

    Science.gov (United States)

    Xue, Bing; Chen, Elton C; He, Nan; Jin, Dao-Zhong; Mao, Li-Min; Wang, John Q

    2017-01-01

    Dopamine (DA) and acetylcholine (ACh) signals converge onto protein kinase A (PKA) in medium spiny neurons of the striatum to control cellular and synaptic activities of these neurons, although underlying molecular mechanisms are less clear. Here we measured phosphorylation of the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) at a PKA site (S845) as an indicator of AMPAR responses in adult rat brains in vivo to explore how DA and ACh interact to modulate AMPARs. We found that subtype-selective activation of DA D1 receptors (D1Rs), D2 receptors (D2Rs), or muscarinic M4 receptors (M4Rs) induced specific patterns of GluA1 S845 responses in the striatum. These defined patterns support a local multitransmitter interaction model in which D2Rs inhibited an intrinsic inhibitory element mediated by M4Rs to enhance the D1R efficacy in modulating AMPARs. Consistent with this, selective enhancement of M4R activity by a positive allosteric modulator resumed the cholinergic inhibition of D1Rs. In addition, D1R and D2R coactivation recruited GluA1 and PKA preferentially to extrasynaptic sites. In sum, our in vivo data support an existence of a dynamic DA-ACh balance in the striatum which actively modulates GluA1 AMPAR phosphorylation and trafficking. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Activity-dependent ubiquitination of GluA1 mediates a distinct AMPA receptor endocytosis and sorting pathway.

    Science.gov (United States)

    Schwarz, Lindsay A; Hall, Benjamin J; Patrick, Gentry N

    2010-12-08

    The accurate trafficking of AMPA receptors (AMPARs) to and from the synapse is a critical component of learning and memory in the brain, whereas dysfunction of AMPAR trafficking is hypothesized to be an underlying mechanism of Alzheimer's disease. Previous work has shown that ubiquitination of integral membrane proteins is a common posttranslational modification used to mediate endocytosis and endocytic sorting of surface proteins in eukaryotic cells. Here we report that mammalian AMPARs become ubiquitinated in response to their activation. Using a mutant of GluA1 that is unable to be ubiquitinated at lysines on its C-terminus, we demonstrate that ubiquitination is required for internalization of surface AMPARs and their trafficking to the lysosome in response to the AMPAR agonist AMPA but not for internalization of AMPARs in response to the NMDA receptor agonist NMDA. Through overexpression or RNA interference-mediated knockdown, we identify that a specific E3 ligase, Nedd4-1 (neural-precursor cell-expressed developmentally downregulated gene 4-1), is necessary for this process. Finally, we show that ubiquitination of GluA1 by Nedd4-1 becomes more prevalent as neurons mature. Together, these data show that ubiquitination of GluA1-containing AMPARs by Nedd4-1 mediates their endocytosis and trafficking to the lysosome. Furthermore, these results provide insight into how hippocampal neurons regulate AMPAR trafficking and degradation with high specificity in response to differing neuronal signaling cues and suggest that changes to this pathway may occur as neurons mature.

  2. The AMPA receptor potentiator Org 26576 modulates stress-induced transcription of BDNF isoforms in rat hippocampus.

    Science.gov (United States)

    Fumagalli, Fabio; Calabrese, Francesca; Luoni, Alessia; Shahid, Mohammed; Racagni, Giorgio; Riva, Marco A

    2012-02-01

    Brain derived neurotrophic factor (BDNF) is a key mediator of brain plasticity. The modulation of its expression and function is important for cognition and represents a key strategy to enhance neuronal resilience. Within this context, there exists a close interaction between glutamatergic neurotransmission and BDNF activity towards regulating cellular homeostasis and plasticity. The aim of the current study was to investigate the ability of the AMPA receptor potentiator Org 26576 to modulate BDNF expression in selected brain regions under basal conditions or in response to an acute swim stress. Rats subjected to a single intraperitoneal injection with Org 26576 (10mg/kg) or saline were exposed to a swim stress session (5 min) and sacrificed 15 min after the end of stress. Real-time PCR assay was used to determine changes in BDNF transcription in different brain regions. Total BDNF mRNA levels were significantly increased in the hippocampus of animals exposed to the combination of Org 26576 and stress whereas, in prefrontal and frontal cortices, BDNF mRNA levels were modulated by the acute stress, independently from drug treatment. The analysis of BDNF transcripts in the hippocampus revealed a major contribution of exons I and IV. Our results suggest that AMPA receptor potentiation by Org 26576 exerts a positive modulatory influence on BDNF expression during ongoing neuronal activity. Given that these mechanisms are critical for neuronal plasticity, we hypothesized that such changes may facilitate learning/coping mechanisms associated with a mild stressful experience. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. GluN2B-containing NMDA receptors and AMPA receptors in medial prefrontal cortex are necessary for odor span in rats

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    Don A Davies

    2013-12-01

    Full Text Available Working memory is a type of short-term memory involved in the maintenance and manipulation of information essential for complex cognition. While memory span capacity has been extensively studied in humans as a measure of working memory, it has received considerably less attention in rodents. Our aim was to examine the role of the NMDA and AMPA glutamate receptors in odor span capacity using systemic injections or infusions of receptor antagonists into the medial prefrontal cortex. Long Evans rats were trained on a well-characterized odor span task. Initially, rats were trained to dig for a food reward in sand followed by training on a non-match to sample discrimination using sand scented with household spices. The rats were then required to perform a serial delayed non-match to sample procedure which was their odor span. Systemic injection of the broad spectrum NMDA receptor antagonist CPP (10 mg/kg or the GluN2B-selective antagonist Ro25-6981 (10 mg/kg but not 6 mg/kg significantly reduced odor span capacity. Infusions of the GluN2B- selective antagonist Ro25-6981 (2.5 µg/hemisphere into medial prefrontal cortex reduced span capacity, an effect that was nearly significant (p = 0.069. Infusions of the AMPA receptor antagonist CNQX (1.25 µg/hemisphere into medial prefrontal cortex reduced span capacity and latency for the rats to make a choice in the task. These results demonstrate span capacity in rats depends on ionotropic glutamate receptor activation in the medial prefrontal cortex. Further understanding of the circuitry underlying span capacity may aid in the novel therapeutic drug development for persons with working memory impairments as a result of disorders such as schizophrenia and Alzheimer’s disease.

  4. Estudio computacional de las relaciones evolutivas de los receptores ionotrópicos NMDA, AMPA y kainato en cuatro especies de primates

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    Francy Johanna Moreno-Pedraza

    2010-12-01

    Full Text Available Computational study of the evolutionary relationships of the ionotropic receptors NMDA, AMPA and kainate in four species ofprimates. Objective. To identify the influence of changes on the secondary structure and evolutionary relationship of NMDA, AMPA andkainate receptors in Homo sapiens, Pan troglodytes, Pongo pygmaeus and Macaca mulatta. Materials and methods. We identified 91sequences for NMDA, AMPA and kainate receptors and analyzed with software for predicting secondary structure, phosphorylation sites,multiple alignments, selection of protein evolution models and phylogenetic prediction. Results. We found that subunits GLUR5, NR2A,NR2C and NR3A showed structural changes in the C-terminal region and formation or loss of phosphorylation sites in this zone.Additionally the phylogenetic prediction suggests that the NMDA NR2 subunits are the closest to the ancestral node that gives rise to theother subunits. Conclusions. Changes in structure and phosphorylation sites in GLUR5, NR2A, NR2C and NR3A subunits suggestvariations in the interaction of the C-terminal region with kinase proteins and with proteins with PDZ domains, which could affect thetrafficking and anchoring of the subunits. On the other hand, the phylogenetic prediction suggests that the changes that occurred in the NR2subunits gave rise to the other subunits of glutamate ionotropic receptors, primarily because the NMDA and particularly the NR2D subunitsare the most closely related to the ancestral node that possibly gave rise to the iGluRs.

  5. The GluR2 hypothesis: Ca(++)-permeable AMPA receptors in delayed neurodegeneration

    NARCIS (Netherlands)

    Bennett, M. V.; Pellegrini-Giampietro, D. E.; Gorter, J. A.; Aronica, E.; Connor, J. A.; Zukin, R. S.

    1996-01-01

    Increased glutamate-receptor-mediated Ca++ influx is considered an important factor underlying delayed neurodegeneration following ischemia or seizures. Until recently, the NMDA receptor was the only glutamate receptor known to be Ca(++)-permeable. It is now well established that glutamate receptors

  6. Blocking Synaptic Removal of GluA2-Containing AMPA Receptors Prevents the Natural Forgetting of Long-Term Memories.

    Science.gov (United States)

    Migues, Paola Virginia; Liu, Lidong; Archbold, Georgina E B; Einarsson, Einar Ö; Wong, Jacinda; Bonasia, Kyra; Ko, Seung Hyun; Wang, Yu Tian; Hardt, Oliver

    2016-03-23

    The neurobiological processes underpinning the natural forgetting of long-term memories are poorly understood. Based on the critical role of GluA2-containing AMPA receptors (GluA2/AMPARs) in long-term memory persistence, we tested in rats whether their synaptic removal underpins time-dependent memory loss. We found that blocking GluA2/AMPAR removal with the interference peptides GluA23Y or G2CT in the dorsal hippocampus during a memory retention interval prevented the normal forgetting of established, long-term object location memories, but did not affect their acquisition. The same intervention also preserved associative memories of food-reward conditioned place preference that would otherwise be lost over time. We then explored whether this forgetting process could play a part in behavioral phenomena involving time-dependent memory change. We found that infusing GluA23Y into the dorsal hippocampus during a 2 week retention interval blocked generalization of contextual fear expression, whereas infusing it into the infralimbic cortex after extinction of auditory fear prevented spontaneous recovery of the conditioned response. Exploring possible physiological mechanisms that could be involved in this form of memory decay, we found that bath application of GluA23Y prevented depotentiation, but not induction of long-term potentiation, in a hippocampal slice preparation. Together, these findings suggest that a decay-like forgetting process that involves the synaptic removal of GluA2/AMPARs erases consolidated long-term memories in the hippocampus and other brain structures over time. This well regulated forgetting process may critically contribute to establishing adaptive behavior, whereas its dysregulation could promote the decline of memory and cognition in neuropathological disorders. The neurobiological mechanisms involved in the natural forgetting of long-term memory and its possible functions are not fully understood. Based on our previous work describing the

  7. Activation of AMPA receptor promotes TNF-α release via the ROS-cSrc-NFκB signaling cascade in RAW264.7 macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xiu-Li [Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Ding, Fan [Office of Scientific R& D, Tsinghua University, Beijing (China); Li, Hui; Tan, Xiao-Qiu [Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Liu, Xiao [Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Cao, Ji-Min, E-mail: caojimin@126.com [Department of Physiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China); Gao, Xue, E-mail: longlongnose@163.com [Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing (China)

    2015-05-29

    The relationship between glutamate signaling and inflammation has not been well defined. This study aimed to investigate the role of AMPA receptor (AMPAR) in the expression and release of tumor necrosis factor-alpha (TNF-α) from macrophages and the underlying mechanisms. A series of approaches, including confocal microscopy, immunofluorescency, flow cytometry, ELISA and Western blotting, were used to estimate the expression of AMPAR and downstream signaling molecules, TNF-α release and reactive oxygen species (ROS) generation in the macrophage-like RAW264.7 cells. The results demonstrated that AMPAR was expressed in RAW264.7 cells. AMPA significantly enhanced TNF-α release from RAW264.7 cells, and this effect was abolished by CNQX (AMPAR antagonist). AMPA also induced elevation of ROS production, phosphorylation of c-Src and activation of nuclear factor (NF)-κB in RAW264.7 cells. Blocking c-Src by PP2, scavenging ROS by glutathione (GSH) or inhibiting NF-κB activation by pyrrolidine dithiocarbamate (PDTC) decreased TNF-α production from RAW264.7 cells. We concluded that AMPA promotes TNF-α release in RAW264.7 macrophages likely through the following signaling cascade: AMPAR activation → ROS generation → c-Src phosphorylation → NF-κB activation → TNF-α elevation. The study suggests that AMPAR may participate in macrophage activation and inflammation. - Highlights: • AMPAR is expressed in RAW264.7 macrophages and is upregulated by AMPA stimulation. • Activation of AMPAR stimulates TNF-α release in macrophages through the ROS-cSrc-NFκB signaling cascade. • Macrophage AMPAR signaling may play an important role in inflammation.

  8. Structure and affinity of two bicyclic glutamate analogues at AMPA and kainate receptors

    DEFF Research Database (Denmark)

    Møllerud, Stine; Pinto, Andrea; Marconi, Laura

    2017-01-01

    Ionotropic glutamate receptors (iGluRs) are involved in most of the fast excitatory synaptic transmission in the central nervous system. These receptors are important for learning and memory formation, but are also involved in the development of diseases such as Alzheimer’s disease, epilepsy...

  9. DHEAS increases levels of GluR2/3 and GluR2, AMPA receptor subunits, in C57BL/6 mice hippocampus El DHEAS incrementa la expresión de GluR2/3 y GLUR2 del receptor AMPA en el hipocampo de ratones C57/BL6

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    Diego Sepúlveda Falla

    2010-05-01

    Full Text Available

    Dehydroepiandrosterone sulfate (DHEA-S is a neurosteroid that has effects such as neuromodulator of synaptic transmission and neuroprotection. The specific signaling pathways for these effects are not elucidated yet. Given that, some neurosteroids act through the activation of ionotropic glutamate receptors, therefore the effect of DHEA-S on the subunits GluR2  and GluR3 of the AMPA receptor was evaluated.  Either DHEA-S or a control substance was administered to C57/BL6 mice. Subunit expression of the AMPA receptor was analyzed by Western blotting.

     

     

    Results show that long-term DHEA-S administration to C57/BL6 mice, increases the protein levels of the subunits GluR2 and GluR2/3 of the AMPA receptors located in the hippocampus.

  10. NMDA and AMPA/kainate glutamatergic receptors in the prelimbic medial prefrontal cortex modulate the elaborated defensive behavior and innate fear-induced antinociception elicited by GABAA receptor blockade in the medial hypothalamus.

    Science.gov (United States)

    de Freitas, Renato Leonardo; Salgado-Rohner, Carlos José; Biagioni, Audrey Francisco; Medeiros, Priscila; Hallak, Jaime Eduardo Cecílio; Crippa, José Alexandre S; Coimbra, Norberto Cysne

    2014-06-01

    The aim of the present study was to investigate the involvement of N-methyl-d-aspartate (NMDA) and amino-3-hydroxy-5-methyl-isoxazole-4-proprionate (AMPA)/kainate receptors of the prelimbic (PL) division of the medial prefrontal cortex (MPFC) on the panic attack-like reactions evoked by γ-aminobutyric acid-A receptor blockade in the medial hypothalamus (MH). Rats were pretreated with NaCl 0.9%, LY235959 (NMDA receptor antagonist), and NBQX (AMPA/kainate receptor antagonist) in the PL at 3 different concentrations. Ten minutes later, the MH was treated with bicuculline, and the defensive responses were recorded for 10 min. The antagonism of NMDA receptors in the PL decreased the frequency and duration of all defensive behaviors evoked by the stimulation of the MH and reduced the innate fear-induced antinociception. However, the pretreatment of the PL cortex with NBQX was able to decrease only part of defensive responses and innate fear-induced antinociception. The present findings suggest that the NMDA-glutamatergic system of the PL is critically involved in panic-like responses and innate fear-induced antinociception and those AMPA/kainate receptors are also recruited during the elaboration of fear-induced antinociception and in panic attack-related response. The activation of the glutamatergic neurotransmission of PL division of the MPFC during the elaboration of oriented behavioral reactions elicited by the chemical stimulation of the MH recruits mainly NMDA receptors in comparison with AMPA/kainate receptors.

  11. Stereostructure-activity studies on agonists at the AMPA and kainate subtypes of ionotropic glutamate receptors

    DEFF Research Database (Denmark)

    Johansen, Tommy N; Greenwood, Jeremy R; Frydenvang, Karla Andrea

    2003-01-01

    (S)-Glutamic acid (Glu), the major excitatory neurotransmitter in the central nervous system, operates through ionotropic as well as metabotropic receptors and is considered to be involved in certain neurological disorders and degenerative brain diseases that are currently without any satisfactory...

  12. Piracetam Defines a New Binding Site for Allosteric Modulators of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors§

    Science.gov (United States)

    Ahmed, Ahmed H.; Oswald, Robert E.

    2010-01-01

    Glutamate receptors are the most prevalent excitatory neurotransmitter receptors in the vertebrate central nervous system and are important potential drug targets for cognitive enhancement and the treatment of schizophrenia. Allosteric modulators of AMPA receptors promote dimerization by binding to a dimer interface and reducing desensitization and deactivation. The pyrrolidine allosteric modulators, piracetam and aniracetam, were among the first of this class of drugs to be discovered. We have determined the structure of the ligand binding domain of the AMPA receptor subtypes GluA2 and GluA3 with piracetam and a corresponding structure of GluA3 with aniracetam. Both drugs bind to both GluA2 and GluA3 in a very similar manner, suggesting little subunit specificity. However, the binding sites for piracetam and aniracetam differ considerably. Aniracetam binds to a symmetrical site at the center of the dimer interface. Piracetam binds to multiple sites along the dimer interface with low occupation, one of which is a unique binding site for potential allosteric modulators. This new site may be of importance in the design of new allosteric regulators. PMID:20163115

  13. Piracetam defines a new binding site for allosteric modulators of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors.

    Science.gov (United States)

    Ahmed, Ahmed H; Oswald, Robert E

    2010-03-11

    Glutamate receptors are the most prevalent excitatory neurotransmitter receptors in the vertebrate central nervous system and are important potential drug targets for cognitive enhancement and the treatment of schizophrenia. Allosteric modulators of AMPA receptors promote dimerization by binding to a dimer interface and reducing desensitization and deactivation. The pyrrolidine allosteric modulators, piracetam and aniracetam, were among the first of this class of drugs to be discovered. We have determined the structure of the ligand binding domain of the AMPA receptor subtypes GluA2 and GluA3 with piracetam and a corresponding structure of GluA3 with aniracetam. Both drugs bind to GluA2 and GluA3 in a very similar manner, suggesting little subunit specificity. However, the binding sites for piracetam and aniracetam differ considerably. Aniracetam binds to a symmetrical site at the center of the dimer interface. Piracetam binds to multiple sites along the dimer interface with low occupation, one of which is a unique binding site for potential allosteric modulators. This new site may be of importance in the design of new allosteric regulators.

  14. Hippocampal GluA1-containing AMPA receptors mediate context-dependent sensitization to morphine

    OpenAIRE

    Xia, Yan; Portugal, George S.; Fakira, Amanda K.; Melyan, Zara; Neve, Rachael; Lee, H. Thomas; Russo, Scott J.; Liu, Jie; Morón, Jose A.

    2011-01-01

    Glutamatergic systems, including α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) are involved in opiate-induced neuronal and behavioral plasticity, although the mechanisms underlying these effects are not fully understood. In the present study, we investigated the effects of repeated morphine administration on AMPAR expression, synaptic plasticity, and context-dependent behavioral sensitization to morphine. We found that morphine treatment produced changes of synaptic...

  15. High-resolution immunogold localization of AMPA type glutamate receptor subunits at synaptic and non-synaptic sites in rat hippocampus.

    Science.gov (United States)

    Baude, A; Nusser, Z; Molnár, E; McIlhinney, R A; Somogyi, P

    1995-12-01

    The cellular and subcellular localization of the GluRA, GluRB/C and GluRD subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type glutamate receptor was determined in the rat hippocampus using polyclonal antipeptide antibodies in immunoperoxidase and immunogold procedures. For the localization of the GluRD subunit a new polyclonal antiserum was developed using the C-terminal sequence of the protein (residues 869-881), conjugated to carrier protein and absorbed to colloidal gold for immunization. The purified antibodies immunoprecipitated about 25% of 3[H]AMPA binding activity from the hippocampus, cerebellum or whole brain, but very little from neocortex. These antibodies did not precipitate a significant amount of 3[H]kainate binding activity. The antibodies also recognize the GluRD subunit, but not the other AMPA receptor subunits, when expressed in transfected COS-7 cells and only when permeabilized with detergent, indicating an intracellular epitope. All subunits were enriched in the neuropil of the dendritic layers of the hippocampus and in the molecular layer of the dentate gyrus. The cellular distribution of the GluRD subunit was studied more extensively. The strata radiatum, oriens and the dentate molecular layer were more strongly immunoreactive than the stratum lacunosum moleculare, the stratum lucidum and the hilus. However, in the stratum lucidum of the CA3 area and in the hilus the weakly reacting dendrites were surrounded by immunopositive rosettes, shown in subsequent electron microscopic studies to correspond to complex dendritic spines. In the stratum radiatum, the weakly reacting apical dendrites contrasted with the surrounding intensely stained neuropil. The cell bodies of pyramidal and granule cells were moderately reactive. Some non-principal cells and their dendrites in the pyramidal cell layer and in the alveus also reacted very strongly for the GluRD subunit. At the subcellular level, silver intensified immunogold

  16. SPARC and GluA1-Containing AMPA Receptors Promote Neuronal Health Following CNS Injury

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    Emma V. Jones

    2018-02-01

    Full Text Available The proper formation and maintenance of functional synapses in the central nervous system (CNS requires communication between neurons and astrocytes and the ability of astrocytes to release neuromodulatory molecules. Previously, we described a novel role for the astrocyte-secreted matricellular protein SPARC (Secreted Protein, Acidic and Rich in Cysteine in regulating α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs and plasticity at developing synapses. SPARC is highly expressed by astrocytes and microglia during CNS development but its level is reduced in adulthood. Interestingly, SPARC has been shown to be upregulated in CNS injury and disease. However, the role of SPARC upregulation in these contexts is not fully understood. In this study, we investigated the effect of chronic SPARC administration on glutamate receptors on mature hippocampal neuron cultures and following CNS injury. We found that SPARC treatment increased the number of GluA1-containing AMPARs at synapses and enhanced synaptic function. Furthermore, we determined that the increase in synaptic strength induced by SPARC could be inhibited by Philanthotoxin-433, a blocker of homomeric GluA1-containing AMPARs. We then investigated the effect of SPARC treatment on neuronal health in an injury context where SPARC expression is upregulated. We found that SPARC levels are increased in astrocytes and microglia following middle cerebral artery occlusion (MCAO in vivo and oxygen-glucose deprivation (OGD in vitro. Remarkably, chronic pre-treatment with SPARC prevented OGD-induced loss of synaptic GluA1. Furthermore, SPARC treatment reduced neuronal death through Philanthotoxin-433 sensitive GluA1 receptors. Taken together, this study suggests a novel role for SPARC and GluA1 in promoting neuronal health and recovery following CNS damage.

  17. Epac Signaling Is Required for Cocaine-Induced Change in AMPA Receptor Subunit Composition in the Ventral Tegmental Area.

    Science.gov (United States)

    Liu, Xiaojie; Chen, Yao; Tong, Jiaqing; Reynolds, Ashley M; Proudfoot, Sarah C; Qi, Jinshun; Penzes, Peter; Lu, Youming; Liu, Qing-Song

    2016-04-27

    Exchange protein directly activated by cAMP (Epac) and protein kinase A (PKA) are intracellular receptors for cAMP. Although PKA and its downstream effectors have been studied extensively in the context of drug addiction, whether and how Epac regulates cellular and behavioral effects of drugs of abuse remain essentially unknown. Epac is known to regulate AMPA receptor (AMPAR) trafficking. Previous studies have shown that a single cocaine exposure in vivo leads to an increase in GluA2-lacking AMPARs in dopamine neurons of the ventral tegmental area (VTA). We tested the hypothesis that Epac mediates cocaine-induced changes in AMPAR subunit composition in the VTA. We report that a single cocaine injection in vivo in wild-type mice leads to inward rectification of EPSCs and renders EPSCs sensitive to a GluA2-lacking AMPAR blocker in VTA dopamine neurons. The cocaine-induced increase in GluA2-lacking AMPARs was absent in Epac2-deficient mice but not in Epac1-deficient mice. In addition, activation of Epac with the selective Epac agonist 8-CPT-2Me-cAMP (8-CPT) recapitulated the cocaine-induced increase in GluA2-lacking AMPARs, and the effects of 8-CPT were mediated by Epac2. We also show that conditioned place preference to cocaine was impaired in Epac2-deficient mice and in mice in which Epac2 was knocked down in the VTA but was not significantly altered in Epac1-deficient mice. Together, these results suggest that Epac2 is critically involved in the cocaine-induced change in AMPAR subunit composition and drug-cue associative learning. Addictive drugs, such as cocaine, induce long-lasting adaptions in the reward circuits of the brain. A single intraperitoneal injection of cocaine leads to changes in the composition and property of the AMPAR that carries excitatory inputs to dopamine neurons. Here, we provide evidence that exchange protein directly activated by cAMP (Epac), a cAMP sensor protein, is required for the cocaine-induced changes of the AMPAR. We found that the

  18. Calcium-permeable AMPA receptors in the VTA and nucleus accumbens after cocaine exposure: When, how and why?

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    Marina E Wolf

    2012-06-01

    Full Text Available In animal models of drug addiction, cocaine exposure has been shown to increase levels of calcium-permeable AMPA receptors (CP-AMPARs in two brain regions that are critical for motivation and reward - the ventral tegmental area (VTA and the nucleus accumbens (NAc. This review compares CP-AMPAR plasticity in the two brain regions and addresses its functional significance. In VTA dopamine neurons, cocaine exposure results in synaptic insertion of high conductance CP-AMPARs in exchange for lower conductance calcium-impermeable AMPARs (CI-AMPARs. This plasticity is rapid (hours, GluA2-dependent, and can be observed with a single cocaine injection. In addition to strengthening synapses and altering Ca2+ signaling, CP-AMPAR insertion affects subsequent induction of plasticity at VTA synapses. However, CP-AMPAR insertion is unlikely to mediate the increased dopamine cell activity that occurs during early withdrawal from cocaine exposure. Within the VTA, the group I metabotropic glutamate receptor mGluR1 exerts a negative influence on CP-AMPAR accumulation. Acutely, mGluR1 stimulation elicits a form of LTD resulting from CP-AMPAR removal and CI-AMPAR insertion. In medium spiny neurons (MSNs of the NAc, extended access cocaine self-administration is required to increase CP-AMPAR levels. This is first detected after approximately a month of withdrawal and then persists. Once present in NAc synapses, CP-AMPARs mediate the expression of incubation of cue-induced cocaine craving. The mechanism of their accumulation may be GluA1-dependent, which differs from that observed in the VTA. However, similar to VTA, mGluR1 stimulation removes CP-AMPARs from MSN synapses. Loss of mGluR1 tone during cocaine withdrawal may contribute to CP-AMPAR accumulation in the NAc. Thus, results in both brain regions point to the possibility of using positive modulators of mGluR1 as a treatment for cocaine addiction.

  19. A role for calcium-permeable AMPA receptors in synaptic plasticity and learning.

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    Brian J Wiltgen

    2010-09-01

    Full Text Available A central concept in the field of learning and memory is that NMDARs are essential for synaptic plasticity and memory formation. Surprisingly then, multiple studies have found that behavioral experience can reduce or eliminate the contribution of these receptors to learning. The cellular mechanisms that mediate learning in the absence of NMDAR activation are currently unknown. To address this issue, we examined the contribution of Ca(2+-permeable AMPARs to learning and plasticity in the hippocampus. Mutant mice were engineered with a conditional genetic deletion of GluR2 in the CA1 region of the hippocampus (GluR2-cKO mice. Electrophysiology experiments in these animals revealed a novel form of long-term potentiation (LTP that was independent of NMDARs and mediated by GluR2-lacking Ca(2+-permeable AMPARs. Behavioral analyses found that GluR2-cKO mice were impaired on multiple hippocampus-dependent learning tasks that required NMDAR activation. This suggests that AMPAR-mediated LTP interferes with NMDAR-dependent plasticity. In contrast, NMDAR-independent learning was normal in knockout mice and required the activation of Ca(2+-permeable AMPARs. These results suggest that GluR2-lacking AMPARs play a functional and previously unidentified role in learning; they appear to mediate changes in synaptic strength that occur after plasticity has been established by NMDARs.

  20. Glutamate receptor antibodies directed against AMPA receptors subunit 3 peptide B (GluR3B) can be produced in DBA/2J mice, lower seizure threshold and induce abnormal behavior.

    Science.gov (United States)

    Ganor, Yonatan; Goldberg-Stern, Hadassa; Cohen, Ran; Teichberg, Vivian; Levite, Mia

    2014-04-01

    Anti-GluR3B antibodies (GluR3B Ab's), directed against peptide B/aa372-395 of GluR3 subunit of glutamate/AMPA receptors, are found in ∼35% of epilepsy patients, activate glutamate/AMPA receptors, evoke ion currents, kill neurons and damage the brain. We recently found that GluR3B Ab's also associate with neurological/psychiatric/behavioral abnormalities in epilepsy patients. Here we asked if GluR3B Ab's could be produced in DBA/2J mice, and also modulate seizure threshold and/or cause behavioral/motor impairments in these mice. DBA/2J mice were immunized with the GluR3B peptide in Complete Freund's Adjuvant (CFA), or with controls: ovalbumin (OVA), CFA, or phosphate-buffer saline (PBS). GluR3B Ab's and OVA Ab's were tested. Seizures were induced in all mice by the chemoconvulsant pentylenetetrazole (PTZ) at three time points, each time with less PTZ to avoid non-specific death. Behavior was examined in Open-Field, RotaRod and Grip tests. GluR3B Ab's were produced only in GluR3B-immunized mice, while OVA Ab's were produced only in OVA-immunized mice, showing high Ab's specificity. In GluR3B Ab's negative mice, seizure severity scores and percentages of animals developing generalized seizures declined in response to decreasing PTZ doses. In contrast, both parameters remained unchanged/high in the GluR3B Ab's positive mice, showing that these mice were more susceptible to seizures. The seizure scores associated significantly with the GluR3B Ab's levels. GluR3B Ab's positive mice were also more anxious in Open-Field test, fell faster in RotaRod test, and fell more in Grip test, compared to all the control mice. GluR3B Ab's are produced in DBA/2J mice, facilitate seizures and induce behavioral/motor impairments. This animal model can therefore serve for studying autoimmune epilepsy and abnormal behavior mediated by pathogenic anti-GluR3B Ab's. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Enhanced Long-Term and Impaired Short-Term Spatial Memory in GluA1 AMPA Receptor Subunit Knockout Mice: Evidence for a Dual-Process Memory Model

    Science.gov (United States)

    Sanderson, David J.; Good, Mark A.; Skelton, Kathryn; Sprengel, Rolf; Seeburg, Peter H.; Rawlins, J. Nicholas P.; Bannerman, David M.

    2009-01-01

    The GluA1 AMPA receptor subunit is a key mediator of hippocampal synaptic plasticity and is especially important for a rapidly-induced, short-lasting form of potentiation. GluA1 gene deletion impairs hippocampus-dependent, spatial working memory, but spares hippocampus-dependent spatial reference memory. These findings may reflect the necessity of…

  2. Association of the AMPA receptor-related postsynaptic density proteins GRIP and ABP with subsets of glutamate-sensitive neurons in the rat retina.

    Science.gov (United States)

    Gábriel, Robert; de Souza, Sunita; Ziff, Edward B; Witkovsky, Paul

    2002-07-22

    We used specific antibodies against two postsynaptic density proteins, GRIP (glutamate receptor interacting protein) and ABP (AMPA receptor-binding protein), to study their distribution in the rat retina. In the central nervous system, it has been shown that both proteins bind strongly to the AMPA glutamate receptor (GluR) 2/3 subunits, but not other GluRs, through a set of three PDZ domains. Western blots detected a single GRIP protein that was virtually identical in retina and brain, whereas retinal ABP corresponded to only one of three ABP peptides found in brain. The retinal distributions of GluR2/3, GRIP, and ABP immunoreactivity (IR) were similar but not identical. GluR2/3 immunoreactivity (IR) was abundant in both plexiform layers and in large perikarya. ABP IR was concentrated in large perikarya but was sparse in the plexiform layers, whereas GRIP IR was relatively more abundant in the plexiform layers than in perikarya. Immunolabel for these three antibodies consisted of puncta ABP IR was examined by double labeling subclasses of retinal neuron with characteristic marker proteins, e.g., calbindin. GRIP, ABP, and GluR2/3 IR were detected in horizontal cells, dopaminergic and glycinergic AII amacrine cells and large ganglion cells. Immunolabel was absent in rod bipolar and weak or absent in cholinergic amacrine cells. By using the tyramide method of signal amplification, a colocalization of GluR2/3 was found with either GRIP or ABP in horizontal cell terminals, and perikarya of amacrine and ganglion cells. Our results show that ABP and GRIP colocalize with GluR2/3 in particular subsets of retinal neuron, as was previously established for certain neurons in the brain. Copyright 2002 Wiley-Liss, Inc.

  3. Role of GluR2 expression in AMPA-induced toxicity in cultured murine cerebral cortical neurons

    DEFF Research Database (Denmark)

    Jensen, Jette Bisgaard; Lund, Trine Meldgaard; Timmermann, Daniel B.

    2001-01-01

    of the Mg(2+) block of the NMDA receptor on AMPA-R stimulation. The involvement of Ca(2+) influx through AMPA-R was also examined. The number of neurons possessing Ca(2+)-permeable AMPA-R increased during culture development, concurrently with an increasing susceptibility for AMPA-induced toxicity during...

  4. AMPA receptor phosphorylation and recognition memory: learning-related, time-dependent changes in the chick brain following filial imprinting.

    Science.gov (United States)

    Solomonia, Revaz O; Meparishvili, Maia; Mikautadze, Ekaterine; Kunelauri, Nana; Apkhazava, David; McCabe, Brian J

    2013-04-01

    There is strong evidence that a restricted part of the chick forebrain, the intermediate medial mesopallium (IMM), stores information acquired through the learning process of visual imprinting. We have previously demonstrated that at 1 h but not 24 h after imprinting training, a learning-specific increase in the amount of membrane Thr286-autophosphorylated α-calcium/calmodulin-dependent protein kinase II (αCaMKII), and in the proportion of total αCaMKII that is phosphorylated, occurs in the IMM but not in a control brain region, the posterior pole of the nidopallium (PPN). αCaMKII directly phosphorylates Ser831 in the GluA1 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor. In the present study we have inquired whether the learning-related increase in αCaMKII autophosphorylation is followed by changes in the Ser831 phosphorylation of GluA1 (P-GluA1) and in the total amount of this subunit (T-GluA1). Trained chicks together with untrained control chicks were killed either 1 or 24 h after training. Tissue was removed from the IMM together with tissue from the PPN as a control. Amounts of P-GluA1 and T-GluA1 were measured. In the left IMM of the 1 h group the P-GluA1/T-GluA1 ratio increased in a learning-specific way. No learning-related changes were observed in other brain regions at 1 h or in any region 24 h after training. The results indicate that a time- and regionally-dependent, learning-specific increase in GluA1 phosphorylation occurs early in recognition memory formation.

  5. Design and synthesis of labeled analogs of PhTX-56, a potent and selective AMPA receptor antagonist

    DEFF Research Database (Denmark)

    Andersen, Trine F; Vogensen, Stine B; Jensen, Lars S

    2005-01-01

    Polyamines and polyamine toxins are biologically important molecules, having modulatory effects on nucleotides and proteins. The wasp toxin, philanthotoxin-433 (PhTX-433), is a non-selective and uncompetitive antagonist of ionotropic receptors, such as ionotropic glutamate receptors and nicotinic...

  6. Potentiation of amygdala AMPA receptor activity selectively promotes escalated alcohol self-administration in a CaMKII-dependent manner.

    Science.gov (United States)

    Cannady, Reginald; Fisher, Kristen R; Graham, Caitlin; Crayle, Jesse; Besheer, Joyce; Hodge, Clyde W

    2017-05-01

    Growing evidence indicates that drugs of abuse gain control over the individual by usurping glutamate-linked mechanisms of neuroplasticity in reward-related brain regions. Accordingly, we have shown that glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) activity in the amygdala is required for the positive reinforcing effects of alcohol, which underlie the initial stages of addiction. It is unknown, however, if enhanced AMPAR activity in the amygdala facilitates alcohol self-administration, which is a kernel premise of glutamate hypotheses of addiction. Here, we show that low-dose alcohol (0.6 g/kg/30 minutes) self-administration increases phosphorylation (activation) of AMPAR subtype GluA1 S831 (pGluA1 S831) in the central amygdala (CeA), basolateral amygdala and nucleus accumbens core (AcbC) of selectively bred alcohol-preferring P-rats as compared with behavior-matched (non-drug) sucrose controls. The functional role of enhanced AMPAR activity was assessed via site-specific infusion of the AMPAR positive modulator, aniracetam, in the CeA and AcbC prior to alcohol self-administration. Intra-CeA aniracetam increased alcohol-reinforced but not sucrose-reinforced responding and was ineffective following intra-AcbC infusion. Because GluA1 S831 is a Ca2+/calmodulin-dependent protein kinase II (CaMKII) substrate, we sought to determine if AMPAR regulation of enhanced alcohol self-administration is dependent on CaMKII activity. Intra-CeA infusion of the cell-permeable CaMKII peptide inhibitor myristolated autocamtide-2-related inhibitory peptide (m-AIP) dose-dependently reduced alcohol self-administration. A subthreshold dose of m-AIP also blocked the aniracetam-induced escalation of alcohol self-administration, demonstrating that AMPAR-mediated potentiation of alcohol reinforcement requires CaMKII activity in the amygdala. Enhanced activity of plasticity-linked AMPAR-CaMKII signaling in the amygdala may promote escalated alcohol use

  7. Histone Deacetylase Inhibition Induces Odor Preference Memory Extension and Maintains Enhanced AMPA Receptor Expression in the Rat Pup Model

    Science.gov (United States)

    Bhattacharya, Sriya; Mukherjee, Bandhan; Doré, Jules J. E.; Yuan, Qi; Harley, Carolyn W.; McLean, John H.

    2017-01-01

    Histone deacetylase (HDAC) plays a role in synaptic plasticity and long-term memory formation. We hypothesized that trichostatin-A (TSA), an HDAC inhibitor, would promote long-term odor preference memory and maintain enhanced GluA1 receptor levels that have been hypothesized to support memory. We used an early odor preference learning model in…

  8. Molecular pharmacology of the AMPA agonist, (S)-2-amino-3-(3-hydroxy-5-phenyl-4-isoxazolyl)propionic acid [(S)-APPA] and the AMPA antagonist, (R)-APPA

    DEFF Research Database (Denmark)

    Ebert, B; Madsen, U; Lund, Trine Meldgaard

    1994-01-01

    )-APPA, whereas (R)-APPA is a non-N-methyl-D-aspartic acid (non-NMDA) receptor antagonist showing preferential AMPA blocking effects. In agreement with classical theories for competitive interaction between agonists and antagonists, the efficacy of depolarizations produced by (S)-APPA in the rat cortical wedge......The heterocyclic analogue of (S)-glutamic acid, (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid [(S)-AMPA] is a potent and selective AMPA receptor agonist, whereas the enantiomeric compound, (R)-AMPA, is virtually inactive. We have previously characterized (RS)-2-amino-3-(3-hydroxy-5......-phenyl-4-isoxazolyl)propionic acid [(RS)-APPA] as a partial AMPA receptor agonist showing about 60% of the efficacy of (RS)-AMPA. This partial agonism produced by (RS)-APPA is, however, only apparent, since resolution of (RS)-APPA has now been shown to provide the full AMPA receptor agonist, (S...

  9. Eating 'Junk-Food' Produces Rapid and Long-Lasting Increases in NAc CP-AMPA Receptors: Implications for Enhanced Cue-Induced Motivation and Food Addiction.

    Science.gov (United States)

    Oginsky, Max F; Goforth, Paulette B; Nobile, Cameron W; Lopez-Santiago, Luis F; Ferrario, Carrie R

    2016-12-01

    Urges to eat are influenced by stimuli in the environment that are associated with food (food cues). Obese people are more sensitive to food cues, reporting stronger craving and consuming larger portions after food cue exposure. The nucleus accumbens (NAc) mediates cue-triggered motivational responses, and activations in the NAc triggered by food cues are stronger in people who are susceptible to obesity. This has led to the idea that alterations in NAc function similar to those underlying drug addiction may contribute to obesity, particularly in obesity-susceptible individuals. Motivational responses are mediated in part by NAc AMPA receptor (AMPAR) transmission, and recent work shows that cue-triggered motivation is enhanced in obesity-susceptible rats after 'junk-food' diet consumption. Therefore, here we determined whether NAc AMPAR expression and function is increased by 'junk-food' diet consumption in obesity-susceptible vs -resistant populations using both outbred and selectively bred models of susceptibility. In addition, cocaine-induced locomotor activity was used as a general 'read out' of mesolimbic function after 'junk-food' consumption. We found a sensitized locomotor response to cocaine in rats that gained weight on a 'junk-food' diet, consistent with greater responsivity of mesolimbic circuits in obesity-susceptible groups. In addition, eating 'junk-food' increased NAc calcium-permeable-AMPAR (CP-AMPAR) function only in obesity-susceptible rats. This increase occurred rapidly, persisted for weeks after 'junk-food' consumption ceased, and preceded the development of obesity. These data are considered in light of enhanced cue-triggered motivation and striatal function in obesity-susceptible rats and the role of NAc CP-AMPARs in enhanced motivation and addiction.

  10. Eating ‘Junk-Food' Produces Rapid and Long-Lasting Increases in NAc CP-AMPA Receptors: Implications for Enhanced Cue-Induced Motivation and Food Addiction

    Science.gov (United States)

    Oginsky, Max F; Goforth, Paulette B; Nobile, Cameron W; Lopez-Santiago, Luis F; Ferrario, Carrie R

    2016-01-01

    Urges to eat are influenced by stimuli in the environment that are associated with food (food cues). Obese people are more sensitive to food cues, reporting stronger craving and consuming larger portions after food cue exposure. The nucleus accumbens (NAc) mediates cue-triggered motivational responses, and activations in the NAc triggered by food cues are stronger in people who are susceptible to obesity. This has led to the idea that alterations in NAc function similar to those underlying drug addiction may contribute to obesity, particularly in obesity-susceptible individuals. Motivational responses are mediated in part by NAc AMPA receptor (AMPAR) transmission, and recent work shows that cue-triggered motivation is enhanced in obesity-susceptible rats after ‘junk-food' diet consumption. Therefore, here we determined whether NAc AMPAR expression and function is increased by ‘junk-food' diet consumption in obesity-susceptible vs -resistant populations using both outbred and selectively bred models of susceptibility. In addition, cocaine-induced locomotor activity was used as a general ‘read out' of mesolimbic function after ‘junk-food' consumption. We found a sensitized locomotor response to cocaine in rats that gained weight on a ‘junk-food' diet, consistent with greater responsivity of mesolimbic circuits in obesity-susceptible groups. In addition, eating ‘junk-food' increased NAc calcium-permeable-AMPAR (CP-AMPAR) function only in obesity-susceptible rats. This increase occurred rapidly, persisted for weeks after ‘junk-food' consumption ceased, and preceded the development of obesity. These data are considered in light of enhanced cue-triggered motivation and striatal function in obesity-susceptible rats and the role of NAc CP-AMPARs in enhanced motivation and addiction. PMID:27383008

  11. D-aspartate and NMDA, but not L-aspartate, block AMPA receptors in rat hippocampal neurons

    DEFF Research Database (Denmark)

    Gong, Xiang-Qun; Frandsen, Anne; Lu, Wei-Yang

    2005-01-01

    1 The amino acid, D-aspartate, exists in the mammalian brain and is an agonist at the N-methyl-D-aspartate (NMDA) subtype of ionotropic glutamate receptors. Here, for the first time, we studied the actions of D-aspartate on alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate receptors (AMPARs......) in acutely isolated rat hippocampal neurons. 2 In the presence of the NMDA receptor channel blocker, MK801, D-aspartate inhibited kainate-induced AMPAR current in hippocampal neurons. The inhibitory action of D-aspartate on kainate-induced AMPAR current was concentration-dependent and was voltage......-independent in the tested voltage range (-80 to +60 mV). 3 The estimated EC50 of the L-glutamate-induced AMPAR current was increased in the presence of D-aspartate, while the estimated maximum L-glutamate-induced AMPAR current was not changed. D-aspartate concentration-dependently shifted the dose-response curve of kainate...

  12. 3-pyrazolone analogues of the 3-isoxazolol metabotropic excitatory amino acid receptor agonist homo-AMPA. Synthesis and pharmacological testing

    DEFF Research Database (Denmark)

    Zimmermann, D.; Janin, Y.L.; Brehm, L.

    1999-01-01

    the terminal carboxyl group has been replaced by various bioisosteric groups, such as phosphonic acid or 3-isoxazolol groups, have been shown to interact selectively with different subtypes of mGlu receptors. In this paper we report the synthesis of the 3-pyrazolone bioisosteres of a-AA, compounds (RS)-2-amino......-4-(1,2-dihydro-5-methyl-3-oxo-3H-pyrazol-4-yl)butyric acid (1) and (RS)-2-amino-4-(1,2-dihydro-1,5-dimethyl-3-oxo-3H-pyrazol-4-yl)butyric acid (2). At a number of steps in the reaction sequences used, the reactions took unexpected courses and provided products which could not be transformed......We have previously shown that the higher homologue of (S)-glutamic acid [(S)-Glu], (S)-a-aminoadipic acid [(S)-a-AA] is selectively recognized by the mGlu and mGlu subtypes of the family of metabotropic glutamic acid (mGlu) receptors. Furthermore, a number of analogues of (S)-a-AA, in which...

  13. Chronic treatment with AMPA receptor potentiator Org 26576 increases neuronal cell proliferation and survival in adult rodent hippocampus.

    Science.gov (United States)

    Su, Xiaowei W; Li, Xiao-Yuan; Banasr, Mounira; Koo, Ja Wook; Shahid, Mohammed; Henry, Brian; Duman, Ronald S

    2009-10-01

    Currently available antidepressants upregulate hippocampal neurogenesis and prefrontal gliogenesis after chronic administration, which could block or reverse the effects of stress. Allosteric alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiators (ARPs), which have novel targets compared to current antidepressants, have been shown to have antidepressant properties in neurogenic and behavioral models. This study analyzed the effect of the ARP Org 26576 on the proliferation, survival, and differentiation of neurons and glia in the hippocampus and prelimbic cortex of adult rats. Male Sprague-Dawley rats received acute (single day) or chronic (21 day) twice-daily intraperitoneal injections of Org 26576 (1-10 mg/kg). Bromodeoxyuridine (BrdU) immunohistochemistry was conducted 24 h or 28 days after the last drug injection for the analysis of cell proliferation or survival, respectively. Confocal immunofluorescence analysis was used to determine the phenotype of surviving cells. Acute administration of Org 26576 did not increase neuronal cell proliferation. However, chronic administration of Org 26576 increased progenitor cell proliferation in dentate gyrus (approximately 40%) and in prelimbic cortex (approximately 35%) at the 10-mg/kg dosage. Cells born in response to chronic Org 26576 in dentate gyrus exhibited increased rates of survival (approximately 30%) with the majority of surviving cells expressing a neuronal phenotype. Findings suggest that Org 26576 may have antidepressant properties, which may be attributed, in part, to upregulation of hippocampal neurogenesis and prelimbic cell proliferation.

  14. Orchestrated regulation of Nogo receptors, LOTUS, AMPA receptors and BDNF in an ECT model suggests opening and closure of a window of synaptic plasticity.

    Directory of Open Access Journals (Sweden)

    Max Nordgren

    Full Text Available Electroconvulsive therapy (ECT is an efficient and relatively fast acting treatment for depression. However, one severe side effect of the treatment is retrograde amnesia, which in certain cases can be long-term. The mechanisms behind the antidepressant effect and the amnesia are not well understood. We hypothesized that ECT causes transient downregulation of key molecules needed to stabilize synaptic structure and to prevent Ca2+ influx, and a simultaneous increase in neurotrophic factors, thus providing a short time window of increased structural synaptic plasticity. Here we followed regulation of NgR1, NgR3, LOTUS, BDNF, and AMPA subunits GluR1 and GluR2 flip and flop mRNA levels in hippocampus at 2, 4, 12, 24, and 72 hours after a single episode of induced electroconvulsive seizures (ECS in rats. NgR1 and LOTUS mRNA levels were transiently downregulated in the dentate gyrus 2, 4, 12 and 4, 12, 24 h after ECS treatment, respectively. GluR2 flip, flop and GluR1 flop were downregulated at 4 h. GluR2 flip remained downregulated at 12 h. In contrast, BDNF, NgR3 and GluR1 flip mRNA levels were upregulated. Thus, ECS treatment induces a transient regulation of factors important for neuronal plasticity. Our data provide correlations between ECS treatment and molecular events compatible with the hypothesis that both effects and side effects of ECT may be caused by structural synaptic rearrangements.

  15. Age-dependent modifications of AMPA receptor subunit expression levels and related cognitive effects in 3xTg-AD mice

    Directory of Open Access Journals (Sweden)

    Pamela eCantanelli

    2014-08-01

    Full Text Available GluA1, GluA2, GluA3, and GluA4 are the constitutive subunits of AMPA receptors (AMPARs, the major mediators of fast excitatory transmission in the mammalian central nervous system. Most AMPARs are Ca2+-impermeable because of the presence of the GluA2 subunit. GluA2 mRNA undergoes an editing process that results in a Q to R substitution, a key factor in the regulation of AMPAR Ca2+-permeability. AMPARs lacking GluA2 or containing the unedited subunit are permeable to Ca2+ and Zn2+. The phenomenon physiologically modulates synaptic plasticity while, in pathologic conditions, leads to increased vulnerability to excitotoxic neuronal death. Given the importance of these subunits, we have therefore evaluated possible associations between changes in expression levels of AMPAR subunits and development of cognitive deficits in 3xTg-AD mice, a widely investigated transgenic mouse model of Alzheimer’s disease. With qRT-PCR, we assayed hippocampal mRNA expression levels of GluA1-4 subunits occurring in young [3 months of age (m.o.a.] and old (12 m.o.a Tg-AD mice and made comparisons with levels found in age-matched wild type (WT mice. Efficiency of GluA2 RNA editing was also analyzed. All animals were cognitively tested for short- and long-term spatial memory with the Morris Water Maze (MWM navigation task. 3xTg-AD mice showed age-dependent decreases of mRNA levels for all the AMPAR subunits, with the exception of GluA2. Editing remained fully efficient with aging in 3xTg-AD and WT mice. A one-to-one correlation analysis between MWM performances and GluA1-4 mRNA expression profiles showed negative correlations between GluA2 levels and MWM performances in young 3xTg-AD mice. On the contrary, positive correlations between GluA2 mRNA and MWM performances were found in young WT mice. Our data suggest that increases of AMPARs that contain GluA1, GluA3, and GluA4 subunits may help in maintaining cognition in pre-symptomatic 3xTg-AD mice.

  16. Role of Site-Specific N-Glycans Expressed on GluA2 in the Regulation of Cell Surface Expression of AMPA-Type Glutamate Receptors.

    Directory of Open Access Journals (Sweden)

    Yusuke Takeuchi

    Full Text Available The AMPA-type glutamate receptor (AMPAR, which is a tetrameric complex composed of four subunits (GluA1-4 with several combinations, mediates the majority of rapid excitatory synaptic transmissions in the nervous system. Cell surface expression levels of AMPAR modulate synaptic plasticity, which is considered one of the molecular bases for learning and memory formation. To date, a unique trisaccharide (HSO3-3GlcAβ1-3Galβ1-4GlcNAc, human natural killer-1 (HNK-1 carbohydrate, was found expressed specifically on N-linked glycans of GluA2 and regulated the cell surface expression of AMPAR and the spine maturation process. However, evidence that the HNK-1 epitope on N-glycans of GluA2 directly affects these phenomena is lacking. Moreover, it is thought that other N-glycans on GluA2 also have potential roles in the regulation of AMPAR functions. In the present study, using a series of mutants lacking potential N-glycosylation sites (N256, N370, N406, and N413 within GluA2, we demonstrated that the mutant lacking the N-glycan at N370 strongly suppressed the intracellular trafficking of GluA2 from the endoplasmic reticulum (ER in HEK293 cells. Cell surface expression of GluA1, which is a major subunit of AMPAR in neurons, was also suppressed by co-expression of the GluA2 N370S mutant. The N370S mutant and wild-type GluA2 were co-immunoprecipitated with GluA1, suggesting that N370S was properly associated with GluA1. Moreover, we found that N413 was the main potential site of the HNK-1 epitope that promoted the interaction of GluA2 with N-cadherin, resulting in enhanced cell surface expression of GluA2. The HNK-1 epitope on N-glycan at the N413 of GluA2 was also involved in the cell surface expression of GluA1. Thus, our data suggested that site-specific N-glycans on GluA2 regulate the intracellular trafficking and cell surface expression of AMPAR.

  17. Influence of early life status epilepticus on the developmental expression profile of the GluA2 subunit of AMPA receptors

    Czech Academy of Sciences Publication Activity Database

    Szczurowska, Ewa; Ergang, Peter; Kubová, Hana; Druga, Rastislav; Salaj, M.; Mareš, Pavel

    2016-01-01

    Roč. 283, Part A (2016), s. 97-109 ISSN 0014-4886 R&D Projects: GA ČR(CZ) GA15-16605S; GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : development * pilocarpine * status epilepticus * LiCl * AMPA * GluA2 * subunit * expression * GRIA2A Subject RIV: FH - Neurology Impact factor: 4.706, year: 2016

  18. Forster Resonance Energy Transfer (FRET) Analysis of Dual CFP/YFP Labeled AMPA Receptors Reveals Structural Rearrangement within the C-Terminal Domain during Receptor Activation

    DEFF Research Database (Denmark)

    Zachariassen, Linda Grønborg; Katchan, Mila; Plested, Andrew

    2014-01-01

    that retain function and display intrareceptor FRET. This includes a construct (GluA2-6Y-10C) containing YFP in the intracellular loop between the M1 and M2 membrane-embedded segments and CFP inserted in the C-ter- minal domain (CTD). GluA2-6Y-10C displays FRET with an efficiency of 0.11 while retaining wild......-type receptor expression and kinetic properties. We have used GluA2-6Y-10C to study conformational changes in homomeric GluA2 receptors during receptor activation. Our results show that the FRET efficiency is dependent on functional state of GluA2-6Y-10C and hereby indi- cates that the intracellular CTD...

  19. GluA2-dependent AMPA receptor endocytosis and the decay of early and late long-term potentiation: possible mechanisms for forgetting of short- and long-term memories.

    Science.gov (United States)

    Hardt, Oliver; Nader, Karim; Wang, Yu-Tian

    2014-01-05

    The molecular processes involved in establishing long-term potentiation (LTP) have been characterized well, but the decay of early and late LTP (E-LTP and L-LTP) is poorly understood. We review recent advances in describing the mechanisms involved in maintaining LTP and homeostatic plasticity. We discuss how these phenomena could relate to processes that might underpin the loss of synaptic potentiation over time, and how they might contribute to the forgetting of short-term and long-term memories. We propose that homeostatic downscaling mediates the loss of E-LTP, and that metaplastic parameters determine the decay rate of L-LTP, while both processes require the activity-dependent removal of postsynaptic GluA2-containing AMPA receptors.

  20. Roles of Fragile X Mental Retardation Protein in Dopaminergic Stimulation-induced Synapse-associated Protein Synthesis and Subsequent α-Amino-3-hydroxyl-5-methyl-4-isoxazole-4-propionate (AMPA) Receptor Internalization*

    Science.gov (United States)

    Wang, Hansen; Kim, Susan S.; Zhuo, Min

    2010-01-01

    Fragile X syndrome, the most common form of inherited mental retardation, is caused by the absence of the RNA-binding protein fragile X mental retardation protein (FMRP). FMRP regulates local protein synthesis in dendritic spines. Dopamine (DA) is involved in the modulation of synaptic plasticity. Activation of DA receptors can regulate higher brain functions in a protein synthesis-dependent manner. Our recent study has shown that FMRP acts as a key messenger for DA modulation in forebrain neurons. Here, we demonstrate that FMRP is critical for DA D1 receptor-mediated synthesis of synapse-associated protein 90/PSD-95-associated protein 3 (SAPAP3) in the prefrontal cortex (PFC). DA D1 receptor stimulation induced dynamic changes of FMRP phosphorylation. The changes in FMRP phosphorylation temporally correspond with the expression of SAPAP3 after D1 receptor stimulation. Protein phosphatase 2A, ribosomal protein S6 kinase, and mammalian target of rapamycin are the key signaling molecules for FMRP linking DA D1 receptors to SAPAP3. Knockdown of SAPAP3 did not affect surface expression of α-amino-3-hydroxyl-5-methyl-4-isoxazole-4-propionate (AMPA) GluR1 receptors induced by D1 receptor activation but impaired their subsequent internalization in cultured PFC neurons; the subsequent internalization of GluR1 was also impaired in Fmr1 knock-out PFC neurons, suggesting that FMRP may be involved in subsequent internalization of GluR1 through regulating the abundance of SAPAP3 after DA D1 receptor stimulation. Our study thus provides further insights into FMRP involvement in DA modulation and may help to reveal the molecular mechanisms underlying impaired learning and memory in fragile X syndrome. PMID:20457613

  1. Roles of fragile X mental retardation protein in dopaminergic stimulation-induced synapse-associated protein synthesis and subsequent alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-4-propionate (AMPA) receptor internalization.

    Science.gov (United States)

    Wang, Hansen; Kim, Susan S; Zhuo, Min

    2010-07-09

    Fragile X syndrome, the most common form of inherited mental retardation, is caused by the absence of the RNA-binding protein fragile X mental retardation protein (FMRP). FMRP regulates local protein synthesis in dendritic spines. Dopamine (DA) is involved in the modulation of synaptic plasticity. Activation of DA receptors can regulate higher brain functions in a protein synthesis-dependent manner. Our recent study has shown that FMRP acts as a key messenger for DA modulation in forebrain neurons. Here, we demonstrate that FMRP is critical for DA D1 receptor-mediated synthesis of synapse-associated protein 90/PSD-95-associated protein 3 (SAPAP3) in the prefrontal cortex (PFC). DA D1 receptor stimulation induced dynamic changes of FMRP phosphorylation. The changes in FMRP phosphorylation temporally correspond with the expression of SAPAP3 after D1 receptor stimulation. Protein phosphatase 2A, ribosomal protein S6 kinase, and mammalian target of rapamycin are the key signaling molecules for FMRP linking DA D1 receptors to SAPAP3. Knockdown of SAPAP3 did not affect surface expression of alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-4-propionate (AMPA) GluR1 receptors induced by D1 receptor activation but impaired their subsequent internalization in cultured PFC neurons; the subsequent internalization of GluR1 was also impaired in Fmr1 knock-out PFC neurons, suggesting that FMRP may be involved in subsequent internalization of GluR1 through regulating the abundance of SAPAP3 after DA D1 receptor stimulation. Our study thus provides further insights into FMRP involvement in DA modulation and may help to reveal the molecular mechanisms underlying impaired learning and memory in fragile X syndrome.

  2. Topiramate via NMDA, AMPA/kainate, GABAA and Alpha2 receptors and by modulation of CREB/BDNF and Akt/GSK3 signaling pathway exerts neuroprotective effects against methylphenidate-induced neurotoxicity in rats.

    Science.gov (United States)

    Motaghinejad, Majid; Motevalian, Manijeh; Fatima, Sulail; Beiranvand, Tabassom; Mozaffari, Shiva

    2017-11-01

    Chronic abuse of methylphenidate (MPH) often causes neuronal cell death. Topiramate (TPM) carries neuroprotective effects, but its exact mechanism of action remains unclear. In the present study, the role of various doses of TPM and its possible mechanisms, receptors and signaling pathways involved against MPH-induced hippocampal neurodegeneration were evaluated in vivo. Thus, domoic acid (DOM) was used as AMPA/kainate receptor agonist, bicuculline (BIC) as GABA A receptor antagonist, ketamine (KET) as NMDA receptor antagonist, yohimbine (YOH) as α 2 adrenergic receptor antagonist and haloperidol (HAL) was used as dopamine D 2 receptor antagonist. Open field test (OFT) was used to investigate the disturbances in motor activity. Hippocampal neurodegenerative parameters were evaluated. Protein expressions of CREB/BDNF and Akt/GSK3 signaling pathways were also evaluated. Cresyl violet staining was performed to show and confirm the changes in the shape of the cells. TPM (70 and 100 mg/kg) reduced MPH-induced rise in lipid peroxidation, oxidized form of glutathione (GSSG), IL-1β and TNF-α levels, Bax expression and motor activity disturbances. In addition, TPM treatment increased Bcl-2 expression, the level of reduced form of glutathione (GSH) and the levels and activities of superoxide dismutase, glutathione peroxidase and glutathione reductase enzymes. TPM also inhibited MPH-induced hippocampal degeneration. Pretreatment of animals with DOM, BIC, KET and YOH inhibited TPM-induced neuroprotection and increased oxidative stress, neuroinflammation, neuroapoptosis and neurodegeneration while reducing CREB, BDNF and Akt protein expressions. Also pretreatment with DOM, BIC, KET and YOH inhibited TPM-induced decreases in GSK3. It can be concluded that the mentioned receptors by modulation of CREB/BDNF and Akt/GSK3 pathways, are involved in neuroprotection of TPM against MPH-induced neurodegeneration.

  3. Transmembrane and ubiquitin-like domain-containing protein 1 (Tmub1/HOPS facilitates surface expression of GluR2-containing AMPA receptors.

    Directory of Open Access Journals (Sweden)

    Hyunjeong Yang

    Full Text Available Some ubiquitin-like (UBL domain-containing proteins are known to play roles in receptor trafficking. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs undergo constitutive cycling between the intracellular compartment and the cell surface in the central nervous system. However, the function of UBL domain-containing proteins in the recycling of the AMPARs to the synaptic surface has not yet been reported.Here, we report that the Transmembrane and ubiquitin-like domain-containing 1 (Tmub1 protein, formerly known as the Hepatocyte Odd Protein Shuttling (HOPS protein, which is abundantly expressed in the brain and which exists in a synaptosomal membrane fraction, facilitates the recycling of the AMPAR subunit GluR2 to the cell surface. Neurons transfected with Tmub1/HOPS-RNAi plasmids showed a significant reduction in the AMPAR current as compared to their control neurons. Consistently, the synaptic surface expression of GluR2, but not of GluR1, was significantly decreased in the neurons transfected with the Tmub1/HOPS-RNAi and increased in the neurons overexpressing EGFP-Tmub1/HOPS. The altered surface expression of GluR2 was speculated to be due to the altered surface-recycling of the internalized GluR2 in our recycling assay. Eventually, we found that GluR2 and glutamate receptor interacting protein (GRIP were coimmunoprecipitated by the anti-Tmub1/HOPS antibody from the mouse brain. Taken together, these observations show that the Tmub1/HOPS plays a role in regulating basal synaptic transmission; it contributes to maintain the synaptic surface number of the GluR2-containing AMPARs by facilitating the recycling of GluR2 to the plasma membrane.

  4. Zebrafish Adar2 Edits the Q/R site of AMPA receptor Subunit gria2α transcript to ensure normal development of nervous system and cranial neural crest cells.

    Directory of Open Access Journals (Sweden)

    I-Chen Li

    Full Text Available BACKGROUND: Adar2 deaminates selective adenosines to inosines (A-to-I RNA editing in the double-stranded region of nuclear transcripts. Although the functions of mouse Adar2 and its biologically most important substrate gria2, encoding the GluA2 subunit of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor, have been extensively studied, the substrates and functions of zebrafish Adar2 remain elusive. METHODS/PRINCIPAL FINDINGS: Expression of Adar2 was perturbed in the adar2 morphant (adar2MO, generated by antisense morpholio oligonucleotides. The Q/R editing of gria2α was reduced in the adar2MO and was enhanced by overexpression of Adar2, demonstrating an evolutionarily conserved activity between zebrafish and mammalian Adar2 in editing the Q/R site of gria2. To delineate the role of Q/R editing of gria2α in the developmental defects observed in the adar2MO, the Q/R editing of gria2α was specifically perturbed in the gria2αQRMO, generated by a morpholio oligonucleotide complementary to the exon complementary sequence (ECS required for the Q/R editing. Analogous to the adar2-deficient and Q/R-editing deficient mice displaying identical neurological defects, the gria2αQRMO and adar2MO displayed identical developmental defects in the nervous system and cranial cartilages. Knockdown p53 abolished apoptosis and partially suppressed the loss of spinal cord motor neurons in these morphants. However, reducing p53 activity neither replenished the brain neuronal populations nor rescued the developmental defects. The expressions of crestin and sox9b in the neural crest cells were reduced in the adar2MO and gria2αQRMO. Overexpressing the edited GluA2αR in the adar2MO restored normal expressions of cresting and sox9b. Moreover, overexpressing the unedited GluA2αQ in the wild type embryos resulted in reduction of crestin and sox9b expressions. These results argue that an elevated GluA2αQ level is sufficient for generating the

  5. Modification of the philanthotoxin-343 polyamine moiety results in different structure-activity profiles at muscle nicotinic ACh, NMDA and AMPA receptors

    DEFF Research Database (Denmark)

    Mellor, I R; Brier, T J; Pluteanu, F

    2003-01-01

    Voltage-dependent, non-competitive inhibition by philanthotoxin-343 (PhTX-343) analogues, with reduced charge or length, of nicotinic acetylcholine receptors (nAChR) of TE671 cells and ionotropic glutamate receptors (N-methyl-D-aspartate receptors (NMDAR) and alpha-amino-3-hydroxy-5-methyl-4...

  6. Selective Reduction of AMPA Currents onto Hippocampal Interneurons Impairs Network Oscillatory Activity

    Science.gov (United States)

    Le Magueresse, Corentin; Monyer, Hannah

    2012-01-01

    Reduction of excitatory currents onto GABAergic interneurons in the forebrain results in impaired spatial working memory and altered oscillatory network patterns in the hippocampus. Whether this phenotype is caused by an alteration in hippocampal interneurons is not known because most studies employed genetic manipulations affecting several brain regions. Here we performed viral injections in genetically modified mice to ablate the GluA4 subunit of the AMPA receptor in the hippocampus (GluA4HC−/− mice), thereby selectively reducing AMPA receptor-mediated currents onto a subgroup of hippocampal interneurons expressing GluA4. This regionally selective manipulation led to a strong spatial working memory deficit while leaving reference memory unaffected. Ripples (125–250 Hz) in the CA1 region of GluA4HC−/− mice had larger amplitude, slower frequency and reduced rate of occurrence. These changes were associated with an increased firing rate of pyramidal cells during ripples. The spatial selectivity of hippocampal pyramidal cells was comparable to that of controls in many respects when assessed during open field exploration and zigzag maze running. However, GluA4 ablation caused altered modulation of firing rate by theta oscillations in both interneurons and pyramidal cells. Moreover, the correlation between the theta firing phase of pyramidal cells and position was weaker in GluA4HC−/− mice. These results establish the involvement of AMPA receptor-mediated currents onto hippocampal interneurons for ripples and theta oscillations, and highlight potential cellular and network alterations that could account for the altered working memory performance. PMID:22675480

  7. Long-term changes in brain following continuous phencyclidine administration: An autoradiographic study using flunitrazepam, ketanserin, mazindol, quinuclidinyl benzilate, piperidyl-3,4-{sup 3}H(N)-TCP, and AMPA receptor ligands

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, Gaylord; Keys, Alan; Noguchi, Kevin [Univ. of California Los Angeles, Dept. of Psychology, Los Angeles, CA (United States)

    1999-05-01

    Phencyclidine induces a model psychosis which can persist for prolonged periods and presents a strong drug model of schizophrenia. When given continuously for several days to rats, phencyclidine and other N-methyl-D-aspartate (NMDA) antagonists induce neural degeneration in a variety of limbic structures, including retrosplenial cortex, hippocampus, septohippocampal projections, and piriform cortex. In an attempt to further clarify the mechanisms underlying these degeneration patterns, autoradiographic studies using a variety of receptor ligands were conducted in animals 21 days after an identical dosage of the continuous phencyclidine administration employed in the previous degeneration studies. The results indicated enduring alterations in a number of receptors: these included decreased piperidyl-3,4-{sup 3}H(N)-TCP (TCP), flunitrazepam, and mazindol binding in many of the limbic regions in which degeneration has been reported previously. Quinuclidinyl benzilate and (AMPA) binding were decreased in anterior cingulate and piriform cortex, and in accumbens and striatum. Piperidyl-3,4-{sup 3}H(N)-TCP binding was decreased in most hippocampal regions. Many of these long-term alterations would not have been predicted by prior studies of the neurotoxic effects of continuous phencyclidine, and these results do not suggest a unitary source for the neurotoxicity. Whereas retrosplenial cortex, the structure which degenerates earliest, showed minimal alterations, some of the most consistent, long term alterations were in structures which evidence no immediate signs of neural degeneration, such as anterior cingulate cortex and caudate nucleus. In these structures, some of the receptor changes appeared to develop gradually (they were not present immediately after cessation of drug administration), and thus were perhaps due to changed input from regions evidencing neurotoxicity. Some of these findings, particularly in anterior cingulate, may have implications for models of

  8. Long-term changes in brain following continuous phencyclidine administration: An autoradiographic study using flunitrazepam, ketanserin, mazindol, quinuclidinyl benzilate, piperidyl-3,4-3H(N)-TCP, and AMPA receptor ligands

    International Nuclear Information System (INIS)

    Ellison, Gaylord; Keys, Alan; Noguchi, Kevin

    1999-01-01

    Phencyclidine induces a model psychosis which can persist for prolonged periods and presents a strong drug model of schizophrenia. When given continuously for several days to rats, phencyclidine and other N-methyl-D-aspartate (NMDA) antagonists induce neural degeneration in a variety of limbic structures, including retrosplenial cortex, hippocampus, septohippocampal projections, and piriform cortex. In an attempt to further clarify the mechanisms underlying these degeneration patterns, autoradiographic studies using a variety of receptor ligands were conducted in animals 21 days after an identical dosage of the continuous phencyclidine administration employed in the previous degeneration studies. The results indicated enduring alterations in a number of receptors: these included decreased piperidyl-3,4- 3 H(N)-TCP (TCP), flunitrazepam, and mazindol binding in many of the limbic regions in which degeneration has been reported previously. Quinuclidinyl benzilate and (AMPA) binding were decreased in anterior cingulate and piriform cortex, and in accumbens and striatum. Piperidyl-3,4- 3 H(N)-TCP binding was decreased in most hippocampal regions. Many of these long-term alterations would not have been predicted by prior studies of the neurotoxic effects of continuous phencyclidine, and these results do not suggest a unitary source for the neurotoxicity. Whereas retrosplenial cortex, the structure which degenerates earliest, showed minimal alterations, some of the most consistent, long term alterations were in structures which evidence no immediate signs of neural degeneration, such as anterior cingulate cortex and caudate nucleus. In these structures, some of the receptor changes appeared to develop gradually (they were not present immediately after cessation of drug administration), and thus were perhaps due to changed input from regions evidencing neurotoxicity. Some of these findings, particularly in anterior cingulate, may have implications for models of

  9. 7-Phenoxy-Substituted 3,4-Dihydro-2H-1,2,4-benzothiadiazine 1,1-Dioxides as Positive Allosteric Modulators of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors with Nanomolar Potency

    DEFF Research Database (Denmark)

    Goffin, Eric; Drapier, Thomas; Larsen, Anja Probst

    2018-01-01

    We report here the synthesis of 7-phenoxy-substituted 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides and their evaluation as AMPA receptor positive allosteric modulators (AMPApams). The impact of substitution on the phenoxy ring and on the nitrogen atom at the 4-position was examined. At GluA2......-ray scattering (SAXS) experiments using isolated GluA2 ligand-binding domain (GluA2-LBD) are consistent with binding of one molecule of 11m per dimer interface, contrary to most benzothiadiazine dioxides developed to date. This observation was confirmed by the X-ray structure of 11m bound to GluA2-LBD and by NMR......(Q) expressed in HEK293 cells (calcium flux experiment), the most potent compound was 11m (4-cyclopropyl-7-(3-methoxyphenoxy)-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide, EC50 = 2.0 nM). The Hill coefficient in the screening and the shape of the dimerization curve in small-angle X...

  10. The number and distribution of AMPA receptor channels containing fast kinetic GluA3 and GluA4 subunits at auditory nerve synapses depend on the target cells.

    Science.gov (United States)

    Rubio, María E; Matsui, Ko; Fukazawa, Yugo; Kamasawa, Naomi; Harada, Harumi; Itakura, Makoto; Molnár, Elek; Abe, Manabu; Sakimura, Kenji; Shigemoto, Ryuichi

    2017-11-01

    The neurotransmitter receptor subtype, number, density, and distribution relative to the location of transmitter release sites are key determinants of signal transmission. AMPA-type ionotropic glutamate receptors (AMPARs) containing GluA3 and GluA4 subunits are prominently expressed in subsets of neurons capable of firing action potentials at high frequencies, such as auditory relay neurons. The auditory nerve (AN) forms glutamatergic synapses on two types of relay neurons, bushy cells (BCs) and fusiform cells (FCs) of the cochlear nucleus. AN-BC and AN-FC synapses have distinct kinetics; thus, we investigated whether the number, density, and localization of GluA3 and GluA4 subunits in these synapses are differentially organized using quantitative freeze-fracture replica immunogold labeling. We identify a positive correlation between the number of AMPARs and the size of AN-BC and AN-FC synapses. Both types of AN synapses have similar numbers of AMPARs; however, the AN-BC have a higher density of AMPARs than AN-FC synapses, because the AN-BC synapses are smaller. A higher number and density of GluA3 subunits are observed at AN-BC synapses, whereas a higher number and density of GluA4 subunits are observed at AN-FC synapses. The intrasynaptic distribution of immunogold labeling revealed that AMPAR subunits, particularly GluA3, are concentrated at the center of the AN-BC synapses. The central distribution of AMPARs is absent in GluA3-knockout mice, and gold particles are evenly distributed along the postsynaptic density. GluA4 gold labeling was homogenously distributed along both synapse types. Thus, GluA3 and GluA4 subunits are distributed at AN synapses in a target-cell-dependent manner.

  11. Acetylcholinesterase potentiates [3H]fluorowillardiine and [3H]AMPA binding to rat cortical membranes

    International Nuclear Information System (INIS)

    Olivera, S.; Rodriguez-Ithurralde, D.; Henley, J.M.

    1999-01-01

    In addition to its action at cholinergic synapses acetylcholinesterase (AChE) has been proposed to modulate neuronal activity by mechanisms unrelated to the hydrolysis of acetylcholine. We have investigated the effects of AChE on the binding of the specific AMPA receptor agonists (S)-[ 3 H]5-fluorowillardiine ([ 3 H]FW) and [ 3 H]AMPA to rat cortical membranes. Pretreatment of membranes with AChE causes a dose-dependent increase in the binding of both radiolabelled agonists with a maximal increase to ∼60% above control. This increase is completely blocked by the specific AChE inhibitors propidium, physostigmine, DFP and BW 284C51. AChE pretreatment had no effect on [ 3 H]kainate binding. [ 3 H]FW binding to membranes from young (15-day-old) rats is four orders of magnitude more sensitive to AChE modulation than membranes from adult rats (EC 50 values of 4x10 -5 and 0.1 unit/ml, respectively) although the total percentage increase in binding is similar. Furthermore, the AChE-induced potentiation of [ 3 H]FW binding is Ca 2+ - and temperature-dependent suggesting an enzymatic action for AChE in this system. Saturation binding experiments with [ 3 H]FW to adult membranes reveal high and low affinity binding sites and demonstrate that the main action of AChE is to increase the B max of both sites. These findings suggest that modulation of AMPA receptors could provide a molecular mechanism of action for the previously reported effects of AChE in synapse formation, synaptic plasticity and neurodegeneration. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. A translational approach to evaluate the efficacy and safety of the novel AMPA receptor positive allosteric modulator org 26576 in adult attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Adler, Lenard A; Kroon, René A; Stein, Mark; Shahid, Mohammed; Tarazi, Frank I; Szegedi, Armin; Schipper, Jacques; Cazorla, Pilar

    2012-12-01

    It has been posited that glutamate dysregulation contributes to the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). Modulation of glutamate neurotransmission may provide alternative therapeutic options. The novel 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid receptor positive allosteric modulator Org 26576 was investigated with a translational approach including preclinical and clinical testing. Neonatal rat 6-hydroxydopamine lesion-induced hyperactivity was used as preclinical model. Seventy-eight ADHD adults entered a multicenter, double-blind, placebo-controlled, two-period crossover trial. After 1 week placebo lead-in, 67 subjects were randomized into one of four treatment sequences: sequence A (n = 15) Org 26576 (100 mg b.i.d.) for 3 weeks, followed by a 2-week placebo crossover and 3 weeks placebo; sequence B (n = 16) 5 weeks placebo followed by 3 weeks Org 26576 (100 mg b.i.d.); sequence C (n = 18) Org 26576 flexible dose (100-300 mg b.i.d.) for 3 weeks, then 5 weeks placebo; sequence D (n = 18) 5 weeks placebo followed by 3 weeks Org 26576 (100-300 mg b.i.d.). The Adult ADHD Investigator Symptom Rating Scale was used to assess changes in ADHD symptomatology. Org 26576 (1, 3, 10 mg/kg intraperitoneal) produced dose-dependent inhibition of locomotor hyperactivity in 6-hydroxydopamine-lesioned rats. Org 26576 (100 mg b.i.d.) was superior to placebo in treating symptoms of adult ADHD subjects. The primary Adult ADHD Investigator Symptom Rating Scale results were supported by some secondary analyses. However, Org 26576 (100-300 mg b.i.d.) did not confirm these results. Most frequently reported adverse events were nausea, dizziness, and headache. These preclinical and clinical findings suggest that Org 25676 may have utility in the treatment of ADHD. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  13. Aspects of dopamine and acetylcholine release induced by glutamate receptors

    International Nuclear Information System (INIS)

    Paes, Paulo Cesar de Arruda

    2002-01-01

    The basal ganglia play an important role in the motor control of rats and humans. This control involves different neurotransmitters and the mutual control of these key elements has been subject to several studies. In this work we determined the role of glutamate on the release of radioactively labelled dopamine and acetylcholine from chopped striatal tissue in vitro. The values of Effective Concentration 50% for glutamate, NMDA, kainic, quisqualic acids and AMPA on the release of dopamine and acetylcholine were obtained. The inhibitory effects of magnesium, tetrodotoxin, MK-801, AP5 and MCPG, as well as the effects of glycin were evaluated. The results suggested that dopamine is influenced by the NMDA type glutamate receptor while acetylcholine seems to be influenced by NMDA, kainate and AMPA receptors. Tetrodotoxin experiments suggested that kainate receptors are both present in cholinergic terminals and cell bodies while AMPA and NMDA receptors are preferentially distributed in cell bodies. Magnesium effectively blocked the NMDA stimulation and unexpectedly also AMPA- and quisqualate-induced acetylcholine release. The latter could not be blocked by MCPG ruling out the participation of methabotropic receptors. MK-801 also blocked NMDA-receptors. Results point out the importance of the glutamic acid control of dopamine and acetylcholine release in striatal tissue. (author)

  14. Enhanced long-term and impaired short-term spatial memory in GluA1 AMPA receptor subunit knockout mice: evidence for a dual-process memory model.

    Science.gov (United States)

    Sanderson, David J; Good, Mark A; Skelton, Kathryn; Sprengel, Rolf; Seeburg, Peter H; Rawlins, J Nicholas P; Bannerman, David M

    2009-06-01

    The GluA1 AMPA receptor subunit is a key mediator of hippocampal synaptic plasticity and is especially important for a rapidly-induced, short-lasting form of potentiation. GluA1 gene deletion impairs hippocampus-dependent, spatial working memory, but spares hippocampus-dependent spatial reference memory. These findings may reflect the necessity of GluA1-dependent synaptic plasticity for short-term memory of recently visited places, but not for the ability to form long-term associations between a particular spatial location and an outcome. This hypothesis is in concordance with the theory that short-term and long-term memory depend on dissociable psychological processes. In this study we tested GluA1-/- mice on both short-term and long-term spatial memory using a simple novelty preference task. Mice were given a series of repeated exposures to a particular spatial location (the arm of a Y-maze) before their preference for a novel spatial location (the unvisited arm of the maze) over the familiar spatial location was assessed. GluA1-/- mice were impaired if the interval between the trials was short (1 min), but showed enhanced spatial memory if the interval between the trials was long (24 h). This enhancement was caused by the interval between the exposure trials rather than the interval prior to the test, thus demonstrating enhanced learning and not simply enhanced performance or expression of memory. This seemingly paradoxical enhancement of hippocampus-dependent spatial learning may be caused by GluA1 gene deletion reducing the detrimental effects of short-term memory on subsequent long-term learning. Thus, these results support a dual-process model of memory in which short-term and long-term memory are separate and sometimes competitive processes.

  15. Alternative Splicing of AMPA subunits in Prefrontal Cortical Fields of Cynomolgus Monkeys following Chronic Ethanol Self-Administration

    Directory of Open Access Journals (Sweden)

    Glen eAcosta

    2012-01-01

    Full Text Available Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in alcohol dependence. To this end, the effects of chronic ethanol self-administration on glutamate receptor ionotropic AMPA (GRIA subunit variant and kainate (GRIK subunit mRNA expression were studied in the orbitofrontal cortex (OFC, dorsolateral prefrontal cortex (DLPFC and anterior cingulate cortex (ACC of male cynomolgus monkeys. In DLPFC, total AMPA splice variant expression and total kainate receptor subunit expression were significantly decreased in alcohol drinking monkeys. Expression levels of GRIA3 flip and flop and GRIA4 flop mRNAs in this region were positively correlated with daily ethanol intake and blood ethanol concentrations averaged over the six months prior to necropsy. In OFC, AMPA subunit splice variant expression was reduced in the alcohol treated group. GRIA2 flop mRNA levels in this region were positively correlated with daily ethanol intake and blood ethanol concentrations averaged over the six months prior to necropsy. Results from these studies provide further evidence of transcriptional regulation of iGluR subunits in the primate brain following chronic alcohol self-administration. Additional studies examining the cellular localization of such effects in the framework of primate prefrontal cortical circuitry are warranted.

  16. Attenuation of ketamine-induced impairment in verbal learning and memory in healthy volunteers by the AMPA receptor potentiator PF-04958242.

    Science.gov (United States)

    Ranganathan, M; DeMartinis, N; Huguenel, B; Gaudreault, F; Bednar, M M; Shaffer, C L; Gupta, S; Cahill, J; Sherif, M A; Mancuso, J; Zumpano, L; D'Souza, D C

    2017-11-01

    There is a need to develop treatments for cognitive impairment associated with schizophrenia (CIAS). The significant role played by N-methyl-d-aspartate receptors (NMDARs) in both the pathophysiology of schizophrenia and in neuronal plasticity suggests that facilitation of NMDAR function might ameliorate CIAS. One strategy to correct NMDAR hypofunction is to stimulate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as AMPAR and NMDAR functioning are coupled and interdependent. In rats and nonhuman primates (NHP), AMPAR potentiators reduce spatial working memory deficits caused by the nonselective NMDAR antagonist ketamine. The current study assessed whether the AMPAR potentiator PF-04958242 would attenuate ketamine-induced deficits in verbal learning and memory in humans. Healthy male subjects (n=29) participated in two randomized treatment periods of daily placebo or PF-04958242 for 5 days separated by a washout period. On day 5 of each treatment period, subjects underwent a ketamine infusion for 75 min during which the effects of PF-04958242/placebo were assessed on ketamine-induced: (1) impairments in verbal learning and recall measured by the Hopkins Verbal Learning Test; (2) impairments in working memory on a CogState battery; and (3) psychotomimetic effects measured by the Positive and Negative Syndrome Scale and Clinician-Administered Dissociative Symptoms Scale. PF-04958242 significantly reduced ketamine-induced impairments in immediate recall and the 2-Back and spatial working memory tasks (CogState Battery), without significantly attenuating ketamine-induced psychotomimetic effects. There were no pharmacokinetic interactions between PF-04958242 and ketamine. Furthermore, PF-04958242 was well tolerated. 'High-impact' AMPAR potentiators like PF-04958242 may have a role in the treatment of the cognitive symptoms, but not the positive or negative symptoms, associated with schizophrenia. The excellent concordance between the

  17. Aspects of dopamine and acetylcholine release induced by glutamate receptors; Aspectos das liberacoes de dopamina e acetilcolina mediadas por receptores de glutamato

    Energy Technology Data Exchange (ETDEWEB)

    Paes, Paulo Cesar de Arruda

    2002-07-01

    The basal ganglia play an important role in the motor control of rats and humans. This control involves different neurotransmitters and the mutual control of these key elements has been subject to several studies. In this work we determined the role of glutamate on the release of radioactively labelled dopamine and acetylcholine from chopped striatal tissue in vitro. The values of Effective Concentration 50% for glutamate, NMDA, kainic, quisqualic acids and AMPA on the release of dopamine and acetylcholine were obtained. The inhibitory effects of magnesium, tetrodotoxin, MK-801, AP5 and MCPG, as well as the effects of glycin were evaluated. The results suggested that dopamine is influenced by the NMDA type glutamate receptor while acetylcholine seems to be influenced by NMDA, kainate and AMPA receptors. Tetrodotoxin experiments suggested that kainate receptors are both present in cholinergic terminals and cell bodies while AMPA and NMDA receptors are preferentially distributed in cell bodies. Magnesium effectively blocked the NMDA stimulation and unexpectedly also AMPA- and quisqualate-induced acetylcholine release. The latter could not be blocked by MCPG ruling out the participation of methabotropic receptors. MK-801 also blocked NMDA-receptors. Results point out the importance of the glutamic acid control of dopamine and acetylcholine release in striatal tissue. (author)

  18. L-glutamate Receptor In Paramecium

    Science.gov (United States)

    Bernal-Martínez, Juan; Ortega-Soto, Arturo

    2004-09-01

    Behavioral, electrophysiological and biochemical experiments were performed in order to establish the presence of a glutamate receptor in the ciliate Paramecium. It was found that an AMPA/KA receptor is functionally expressed in Paramecium and that this receptor is immunologically and fillogenetically related to the AMPA/KA receptor present in vertebrates.

  19. Monitoring glyphosate and AMPA concentrations in wells and drains using the sorbicell passive sampler

    DEFF Research Database (Denmark)

    Vendelboe, Anders Lindblad; de Jonge, Hubert; Møldrup, Per

    2012-01-01

    Glyphosate is one of the world’s most extensively used weed control agents. Glyphosate, and its metabolite aminomethylphosphonic acid (AMPA), are suspected to be hazardous to human health and the aquatic environment. In Denmark, the extensive use has resulted in an increasing number of occurrences......Cell, will decrease the workload and number of samples freeing up funds for larger monitoring programs. When installed in a well the SorbiCell will continuously sample the water giving either a flux-weighed or time-weighted average measurement of the glyphosate/AMPA concentration throughout the sampling period....... It may therefore be possible to measure lower concentrations as the glyphosate/AMPA sorbed in the SorbiCell is an accumulated measurement. Also, glyphosate/AMPA associated with sudden flush events will be detected by the SorbiCells, while such events may pass between two consecutive grab samples...

  20. Acetylcholinesterase potentiates [{sup 3}H]fluorowillardiine and [{sup 3}H]AMPA binding to rat cortical membranes

    Energy Technology Data Exchange (ETDEWEB)

    Olivera, S.; Rodriguez-Ithurralde, D. [Department of Anatomy, School of Medical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD (United Kingdom); Henley, J.M. [Molecular Neuroscience Unit, Division Neuromyology, Instituto de Investigaciones Biologicas Clemente Estable, 11600 Montevideo (Uruguay)

    1999-04-01

    In addition to its action at cholinergic synapses acetylcholinesterase (AChE) has been proposed to modulate neuronal activity by mechanisms unrelated to the hydrolysis of acetylcholine. We have investigated the effects of AChE on the binding of the specific AMPA receptor agonists (S)-[{sup 3}H]5-fluorowillardiine ([{sup 3}H]FW) and [{sup 3}H]AMPA to rat cortical membranes. Pretreatment of membranes with AChE causes a dose-dependent increase in the binding of both radiolabelled agonists with a maximal increase to {approx}60% above control. This increase is completely blocked by the specific AChE inhibitors propidium, physostigmine, DFP and BW 284C51. AChE pretreatment had no effect on [{sup 3}H]kainate binding. [{sup 3}H]FW binding to membranes from young (15-day-old) rats is four orders of magnitude more sensitive to AChE modulation than membranes from adult rats (EC{sub 50} values of 4x10{sup -5} and 0.1 unit/ml, respectively) although the total percentage increase in binding is similar. Furthermore, the AChE-induced potentiation of [{sup 3}H]FW binding is Ca{sup 2+}- and temperature-dependent suggesting an enzymatic action for AChE in this system. Saturation binding experiments with [{sup 3}H]FW to adult membranes reveal high and low affinity binding sites and demonstrate that the main action of AChE is to increase the B{sub max} of both sites. These findings suggest that modulation of AMPA receptors could provide a molecular mechanism of action for the previously reported effects of AChE in synapse formation, synaptic plasticity and neurodegeneration. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. MET receptor tyrosine kinase controls dendritic complexity, spine morphogenesis, and glutamatergic synapse maturation in the hippocampus.

    Science.gov (United States)

    Qiu, Shenfeng; Lu, Zhongming; Levitt, Pat

    2014-12-03

    The MET receptor tyrosine kinase (RTK), implicated in risk for autism spectrum disorder (ASD) and in functional and structural circuit integrity in humans, is a temporally and spatially regulated receptor enriched in dorsal pallial-derived structures during mouse forebrain development. Here we report that loss or gain of function of MET in vitro or in vivo leads to changes, opposite in nature, in dendritic complexity, spine morphogenesis, and the timing of glutamatergic synapse maturation onto hippocampus CA1 neurons. Consistent with the morphological and biochemical changes, deletion of Met in mutant mice results in precocious maturation of excitatory synapse, as indicated by a reduction of the proportion of silent synapses, a faster GluN2A subunit switch, and an enhanced acquisition of AMPA receptors at synaptic sites. Thus, MET-mediated signaling appears to serve as a mechanism for controlling the timing of neuronal growth and functional maturation. These studies suggest that mistimed maturation of glutamatergic synapses leads to the aberrant neural circuits that may be associated with ASD risk. Copyright © 2014 the authors 0270-6474/14/3416166-14$15.00/0.

  2. Role of ionotropic GABA, glutamate and glycine receptors in the tonic and reflex control of cardiac vagal outflow in the rat

    Directory of Open Access Journals (Sweden)

    Goodchild Ann K

    2010-10-01

    Full Text Available Abstract Background Cardiac vagal preganglionic neurons (CVPN are responsible for the tonic, reflex and respiratory modulation of heart rate (HR. Although CVPN receive GABAergic and glutamatergic inputs, likely involved in respiratory and reflex modulation of HR respectively, little else is known regarding the functions controlled by ionotropic inputs. Activation of g-protein coupled receptors (GPCR alters these inputs, but the functional consequence is largely unknown. The present study aimed to delineate how ionotropic GABAergic, glycinergic and glutamatergic inputs contribute to the tonic and reflex control of HR and in particular determine which receptor subtypes were involved. Furthermore, we wished to establish how activation of the 5-HT1A GPCR affects tonic and reflex control of HR and what ionotropic interactions this might involve. Results Microinjection of the GABAA antagonist picrotoxin into CVPN decreased HR but did not affect baroreflex bradycardia. The glycine antagonist strychnine did not alter HR or baroreflex bradycardia. Combined microinjection of the NMDA antagonist, MK801, and AMPA antagonist, CNQX, into CVPN evoked a small bradycardia and abolished baroreflex bradycardia. MK801 attenuated whereas CNQX abolished baroreceptor bradycardia. Control intravenous injections of the 5-HT1A agonist 8-OH-DPAT evoked a small bradycardia and potentiated baroreflex bradycardia. These effects were still observed following microinjection of picrotoxin but not strychnine into CVPN. Conclusions We conclude that activation of GABAA receptors set the level of HR whereas AMPA to a greater extent than NMDA receptors elicit baroreflex changes in HR. Furthermore, activation of 5-HT1A receptors evokes bradycardia and enhances baroreflex changes in HR due to interactions with glycinergic neurons involving strychnine receptors. This study provides reference for future studies investigating how diseases alter neurochemical inputs to CVPN.

  3. Comparison of excitotoxic profiles of ATPA, AMPA, KA and NMDA in organotypic hippocampal slice cultures

    DEFF Research Database (Denmark)

    Kristensen, Bjarne Winther; Noraberg, J; Zimmer, J

    2001-01-01

    ) values was found after 2 days of exposure: AMPA (3.7 mM)>NMDA (11 mM)=KA (13 mM)>ATPA (33 mM). Exposed to 30 microM ATPA, 3 microM AMPA and 10 microM NMDA, CA1 was the most susceptible subfield followed by fascia dentata and CA3. Using 8 microM KA, CA3 was the most susceptible subfield, followed...... by fascia dentata and CA1. In 100 microM concentrations, all four agonists induced the same, maximal PI uptake in all hippocampal subfields, corresponding to total neuronal degeneration. Using glutamate receptor antagonists, like GYKI 52466, NBQX and MK-801, inhibition data revealed that AMPA excitotoxicity...

  4. Glutamatergic Receptor Activation in the Commisural Nucleus Tractus Solitarii (cNTS) Mediates Brain Glucose Retention (BGR) Response to Anoxic Carotid Chemoreceptor (CChr) Stimulation in Rats.

    Science.gov (United States)

    Cuéllar, R; Montero, S; Luquín, S; García-Estrada, J; Dobrovinskaya, O; Melnikov, V; Lemus, M; de Álvarez-Buylla, E Roces

    2015-01-01

    Glutamate, released from central terminals of glossopharyngeal nerve, is a major excitatory neurotransmitter of commissural nucleus tractus solitarii (cNTS) afferent terminals, and brain derived neurotrophic factor (BDNF) has been shown to attenuate glutamatergic AMPA currents in NTS neurons. To test the hypothesis that AMPA contributes to glucose regulation in vivo modulating the hyperglycemic reflex with brain glucose retention (BGR), we microinjected AMPA and NBQX (AMPA antagonist) into the cNTS before carotid chemoreceptor stimulation in anesthetized normal Wistar rats, while hyperglycemic reflex an brain glucose retention (BGR) were analyzed. To investigate the underlying mechanisms, GluR2/3 receptor and c-Fos protein expressions in cNTS neurons were determined. We showed that AMPA in the cNTS before CChr stimulation inhibited BGR observed in aCSF group. In contrast, NBQX in similar conditions, did not modify the effects on glucose variables observed in aCSF control group. These experiments suggest that glutamatergic pathways, via AMPA receptors, in the cNTS may play a role in glucose homeostasis.

  5. Modulator effects of interleukin-1beta and tumor necrosis factor-alpha on AMPA-induced excitotoxicity in mouse organotypic hippocampal slice cultures

    DEFF Research Database (Denmark)

    Bernardino, Liliana; Xapelli, Sara; Silva, Ana P

    2005-01-01

    The inflammatory cytokines interleukin-1beta and tumor necrosis factor-alpha (TNF-alpha) have been identified as mediators of several forms of neurodegeneration in the brain. However, they can produce either deleterious or beneficial effects on neuronal function. We investigated the effects...... of mouse recombinant TNF-alpha (10 ng/ml) enhanced excitotoxicity when the cultures were simultaneously exposed to AMPA and to this cytokine. Decreasing the concentration of TNF-alpha to 1 ng/ml resulted in neuroprotection against AMPA-induced neuronal death independently on the application protocol....... By using TNF-alpha receptor (TNFR) knock-out mice, we demonstrated that the potentiation of AMPA-induced toxicity by TNF-alpha involves TNF receptor-1, whereas the neuroprotective effect is mediated by TNF receptor-2. AMPA exposure was associated with activation and proliferation of microglia as assessed...

  6. Quality control of estrogen receptor assays.

    Science.gov (United States)

    Godolphin, W; Jacobson, B

    1980-01-01

    Four types of material have been used for the quality control of routine assays of estrogen receptors in human breast tumors. Pieces of hormone-dependent Nb rat mammary tumors gave a precision about 40%. Rat uteri and rat tumors pulverized at liquid nitrogen temperature and stored as powder yielded precision about 30%. Powdered and lyophilised human tumors appear the best with precision as good as 17%.

  7. Especificaciones del servicio de medición y control de la presión arterial mediante MAFC, AMPA y MAPA

    Directory of Open Access Journals (Sweden)

    SEFAC-Comisión-Servicios-Profesionales-Farmacéuticos.

    2016-06-01

    Full Text Available En abril de 2013, la Sociedad Española de Farmacia Familiar y Comunitaria ­(SEFAC presentó su propuesta sobre servicios profesionales farmacéuticos (SPF cuyo fin es cubrir las necesidades relacionadas tanto con la atención de los pacientes que utilizan medicamentos, como con la salud pública. Esta propuesta ofrece un planteamiento sobre la implantación y desarrollo de los SPF con el objetivo de impulsar su prestación por las farmacias comunitarias en los próximos años. De acuerdo con dicha propuesta todos los SPF que constituyen el catálogo de servicios contarán con un documento de especificaciones. El objeto de este documento de especificaciones es definir y caracterizar el servicio de medición y control de la presión arterial con un doble objeto: • Ayudar al farmacéutico comunitario y a sus representantes en el ofrecimiento, prestación, difusión, financiación y concertación de este servicio. • Servir de guía a los farmacéuticos comunitarios que desean implantar este servicio en la farmacia o elaborar un procedimiento normalizado de trabajo para su realización. Este documento se complementa con la Guía de actuación para el farmacéutico comunitario en pacientes con HTA y riesgo cardiovascular (RCV. Documento de consenso GIAF-UGR, SEFAC y SEH-LELHA y con el programa impacHta: formación de SEFAC y SEH-LELHA en hipertensión y riesgo vascular.

  8. Chronic Stress Triggers Expression of Immediate Early Genes and Differentially Affects the Expression of AMPA and NMDA Subunits in Dorsal and Ventral Hippocampus of Rats

    Directory of Open Access Journals (Sweden)

    Anibal Pacheco

    2017-08-01

    Full Text Available Previous studies in rats have demonstrated that chronic restraint stress triggers anhedonia, depressive-like behaviors, anxiety and a reduction in dendritic spine density in hippocampal neurons. In this study, we compared the effect of repeated stress on the expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA and N-methyl-D-aspartate (NMDA receptor subunits in dorsal and ventral hippocampus (VH. Adult male Sprague-Dawley rats were randomly divided into control and stressed groups, and were daily restrained in their motion (2.5 h/day during 14 days. We found that chronic stress promotes an increase in c-Fos mRNA levels in both hippocampal areas, although it was observed a reduction in the immunoreactivity at pyramidal cell layer. Furthermore, Arc mRNAs levels were increased in both dorsal and VH, accompanied by an increase in Arc immunoreactivity in dendritic hippocampal layers. Furthermore, stress triggered a reduction in PSD-95 and NR1 protein levels in whole extract of dorsal and VH. Moreover, a reduction in NR2A/NR2B ratio was observed only in dorsal pole. In synaptosomal fractions, we detected a rise in NR1 in dorsal hippocampus (DH. By indirect immunofluorescence we found that NR1 subunits rise, especially in neuropil areas of dorsal, but not VH. In relation to AMPA receptor (AMPAR subunits, chronic stress did not trigger any change, either in dorsal or ventral hippocampal areas. These data suggest that DH is more sensitive than VH to chronic stress exposure, mainly altering the expression of NMDA receptor (NMDAR subunits, and probably favors changes in the configuration of this receptor that may influence the function of this area.

  9. Roles of Fragile X Mental Retardation Protein in Dopaminergic Stimulation-induced Synapse-associated Protein Synthesis and Subsequent α-Amino-3-hydroxyl-5-methyl-4-isoxazole-4-propionate (AMPA) Receptor Internalization*

    OpenAIRE

    Wang, Hansen; Kim, Susan S.; Zhuo, Min

    2010-01-01

    Fragile X syndrome, the most common form of inherited mental retardation, is caused by the absence of the RNA-binding protein fragile X mental retardation protein (FMRP). FMRP regulates local protein synthesis in dendritic spines. Dopamine (DA) is involved in the modulation of synaptic plasticity. Activation of DA receptors can regulate higher brain functions in a protein synthesis-dependent manner. Our recent study has shown that FMRP acts as a key messenger for DA modulation in forebrain ne...

  10. Role of desensitization and subunit expression for kainate receptor-mediated neurotoxicity in murine neocortical cultures

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1999-01-01

    ) toxicity mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, and (3) toxicity that can be mediated by kainate receptors when desensitization of the receptors is blocked. The indirect action at NMDA receptors was discovered because (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H...... nedioxy-5H-2,3-benzodiazepine (GYKI 53655), a selective AMPA receptor antagonist, abolished the remaining toxicity. These results indicated that kainate- and domoate-mediated toxicity involves both the NMDA and the AMPA receptors. Pretreatment of the cultures with concanavalin A to prevent desensitization...

  11. Involvement of AMPA receptor GluR2 and GluR3 trafficking in trigeminal spinal subnucleus caudalis and C1/C2 neurons in acute-facial inflammatory pain.

    Directory of Open Access Journals (Sweden)

    Makiko Miyamoto

    Full Text Available To evaluate the involvement of trafficking of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR GluR2 and GluR3 subunits in an acute inflammatory orofacial pain, we analyzed nocifensive behavior, phosphorylated extracellular signal-regulated kinase (pERK and Fos expression in Vi/Vc, Vc and C1/C2 in GluR2 delta7 knock-in (KI, GluR3 delta7 KI mice and wild-type mice. We also studied Vc neuronal activity to address the hypothesis that trafficking of GluR2 and GluR3 subunits plays an important role in Vi/Vc, Vc and C1/C2 neuronal activity associated with orofacial inflammation in these mice. Late nocifensive behavior was significantly depressed in GluR2 delta7 KI and GluR3 delta7 KI mice. In addition, the number of pERK-immunoreactive (IR cells was significantly decreased bilaterally in the Vi/Vc, Vc and C1/C2 in GluR2 delta7 KI and GluR3 delta7 KI mice compared to wild-type mice at 40 min after formalin injection, and was also significantly smaller in GluR3 delta7 KI compared to GluR2 delta7 KI mice. The number of Fos protein-IR cells in the ipsilateral Vi/Vc, Vc and C1/C2 was also significantly smaller in GluR2 delta7 KI and GluR3 delta7 KI mice compared to wild-type mice 40 min after formalin injection. Nociceptive neurons functionally identified as wide dynamic range neurons in the Vc, where pERK- and Fos protein-IR cell expression was prominent, showed significantly lower spontaneous activity in GluR2 delta7 KI and GluR3 delta7 KI mice than wild-type mice following formalin injection. These findings suggest that GluR2 and GluR3 trafficking is involved in the enhancement of Vi/Vc, Vc and C1/C2 nociceptive neuronal excitabilities at 16-60 min following formalin injection, resulting in orofacial inflammatory pain.

  12. Ghrelin receptor controls obesity by fat burning

    Science.gov (United States)

    Emerging evidence show that brown fat in the body produces heat to burn energy, thus prompting weight loss. Ghrelin is the only known hormone which increases appetite and promotes weight gain. We have reported that mice that lack the receptor which mediates the functions of ghrelin are lean. Our fu...

  13. Expression and localization of ionotropic glutamate receptor subunits in the goldfish retina--an in situ hybridization and immunocytochemical study

    NARCIS (Netherlands)

    Vandenbranden, C. A.; Kamphuis, W.; Nunes Cardozo, B.; Kamermans, M.

    2000-01-01

    The expression and distribution of AMPA, kainate and NMDA glutamate receptor subunits was studied in the goldfish retina. For the immunocytochemical localization of the AMPA receptor antisera against GluR2, GluR2/3 and GluR4 were used, and for in situ hybridization rat specific probes for GluR1 and

  14. Structural rearrangement of the intracellular domains during AMPA receptor activation

    DEFF Research Database (Denmark)

    Zachariassen, Linda Grønborg; Katchan, Ljudmila; Jensen, Anna Guldvang

    2016-01-01

    -clamp fluorometry of the double- and single-insert constructs showed that both the intracellular C-terminal domain (CTD) and the loop region between the M1 and M2 helices move during activation and the CTD is detached from the membrane. Our time-resolved measurements revealed unexpectedly complex fluorescence...

  15. Glyphosate and AMPA, "pseudo-persistent" pollutants under real-world agricultural management practices in the Mesopotamic Pampas agroecosystem, Argentina.

    Science.gov (United States)

    Primost, Jezabel E; Marino, Damián J G; Aparicio, Virginia C; Costa, José Luis; Carriquiriborde, Pedro

    2017-10-01

    In the Pampas, public concern has strongly risen because of the intensive use of glyphosate for weed control and fallow associated with biotech crops. The present study was aimed to evaluate the occurrence and concentration of the herbicide and its main metabolite (AMPA) in soil and other environmental compartments of the mentioned agroecosystem, including groundwater, in relation to real-world agricultural management practices in the region. Occurrence was almost ubiquitous in solid matrices (83-100%) with maximum concentrations among the higher reported in the world (soil: 8105 and 38939; sediment: 3294 and 7219; suspended particulate matter (SPM): 584 and 475 μg/kg of glyphosate and AMPA). Lower detection frequency was observed in surface water (27-55%) with maximum concentrations in whole water of 1.80 and 1.90 μg/L of glyphosate and AMPA, indicating that SPM analysis would be more sensitive for detection in the aquatic ecosystem. No detectable concentrations of glyphosate or AMPA were observed in groundwater. Glyphosate soil concentrations were better correlated with the total cumulative dose and total number of applications than the last spraying event dose, and an increment of 1 mg glyphosate/kg soil every 5 spraying events was estimated. Findings allow to infer that, under current practices, application rates are higher than dissipation rates. Hence, glyphosate and AMPA should be considered "pseudo-persistent" pollutants and a revisions of management procedures, monitoring programs, and ecological risk for soil and sediments should be also recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Receptor control in mesenchymal stem cell engineering

    Science.gov (United States)

    Dalby, Matthew J.; García, Andrés J.; Salmeron-Sanchez, Manuel

    2018-03-01

    Materials science offers a powerful tool to control mesenchymal stem cell (MSC) growth and differentiation into functional phenotypes. A complex interplay between the extracellular matrix and growth factors guides MSC phenotypes in vivo. In this Review, we discuss materials-based bioengineering approaches to direct MSC fate in vitro and in vivo, mimicking cell-matrix-growth factor crosstalk. We first scrutinize MSC-matrix interactions and how the properties of a material can be tailored to support MSC growth and differentiation in vitro, with an emphasis on MSC self-renewal mechanisms. We then highlight important growth factor signalling pathways and investigate various materials-based strategies for growth factor presentation and delivery. Integrin-growth factor crosstalk in the context of MSC engineering is introduced, and bioinspired material designs with the potential to control the MSC niche phenotype are considered. Finally, we summarize important milestones on the road to MSC engineering for regenerative medicine.

  17. Maximum tolerated dose evaluation of the AMPA modulator Org 26576 in healthy volunteers and depressed patients: a summary and method analysis of bridging research in support of phase II dose selection.

    Science.gov (United States)

    Nations, Kari R; Bursi, Roberta; Dogterom, Peter; Ereshefsky, Larry; Gertsik, Lev; Mant, Tim; Schipper, Jacques

    2012-09-01

    A key challenge to dose selection in early central nervous system (CNS) clinical drug development is that patient tolerability profiles often differ from those of healthy volunteers (HVs), yet HVs are the modal population for determining doses to be investigated in phase II trials. Without clear tolerability data from the target patient population, first efficacy trials may include doses that are either too high or too low, creating undue risk for study participants and the development program overall. Bridging trials address this challenge by carefully investigating safety and tolerability in the target population prior to full-scale proof-of-concept trials. Org 26576 is an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor positive allosteric modulator that acts by modulating ionotropic AMPA-type glutamate receptors to enhance glutamatergic neurotransmission. In preparation for phase II efficacy trials in major depressive disorder (MDD), two separate phase I trials were conducted to evaluate safety, tolerability, and pharmacokinetics in HVs and in the target patient population. Both trials were randomized and placebo controlled, and included multiple rising-dose cohorts (HV range 100-400 mg bid; MDD range 100-600 mg bid). HVs (n = 36) and patients with MDD (n = 54) were dosed under similarly controlled conditions in an inpatient facility, HVs for up to 14 days and MDD patients for up to 28 days. Safety, tolerability, and pharmacokinetics were assessed frequently. Despite comparable pharmacokinetic profiles, the maximum tolerated dose (MTD) in depressed patients was 450 mg bid, twice the MTD established in HVs. No clinically relevant safety issues associated with Org 26576 were noted. This article presents safety, tolerability, and pharmacokinetic data from two different populations examined under similar dosing conditions. The important implications of such bridging work in phase II dose selection are discussed, as are study

  18. NMDA receptors mediate neuron-to-glia signaling in mouse cortical astrocytes.

    Science.gov (United States)

    Lalo, Ulyana; Pankratov, Yuri; Kirchhoff, Frank; North, R Alan; Verkhratsky, Alexei

    2006-03-08

    Chemical transmission between neurons and glial cells is an important element of integration in the CNS. Here, we describe currents activated by NMDA in cortical astrocytes, identified in transgenic mice that express enhanced green fluorescent protein under control of the human glial fibrillary acidic protein promoter. Astrocytes were studied by whole-cell voltage clamp either in slices or after gentle nonenzymatic mechanical dissociation. Acutely isolated astrocytes showed a three-component response to glutamate. The initial rapid component was blocked by 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX), which is an antagonist of AMPA receptors (IC50, 2 microM), and the NMDA receptor antagonist D-AP-5 blocked the later sustained component (IC50, 0.6 microM). The third component of glutamate application response was sensitive to D,L-threo-beta-benzyloxyaspartate, a glutamate transporter blocker. Fast application of NMDA evoked concentration-dependent inward currents (EC50, 0.3 microM); these showed use-dependent block by (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate (MK-801). These NMDA-evoked currents were linearly dependent on membrane potential and were not affected by extracellular magnesium at concentrations up to 10 mM. Electrical stimulation of axons in layer IV-VI induced a complex inward current in astrocytes situated in the cortical layer II, part of which was sensitive to MK-801 at holding potential -80 mV and was not affected by the AMPA glutamate receptor antagonist NBQX. The fast miniature spontaneous currents were observed in cortical astrocytes in slices as well. These currents exhibited both AMPA and NMDA receptor-mediated components. We conclude that cortical astrocytes express functional NMDA receptors that are devoid of Mg2+ block, and these receptors are involved in neuronal-glial signal transmission.

  19. Glutamate receptor antibodies in neurological diseases: anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies, anti-NMDA-NR2A/B antibodies, anti-mGluR1 antibodies or anti-mGluR5 antibodies are present in subpopulations of patients with either: epilepsy, encephalitis, cerebellar ataxia, systemic lupus erythematosus (SLE) and neuropsychiatric SLE, Sjogren's syndrome, schizophrenia, mania or stroke. These autoimmune anti-glutamate receptor antibodies can bind neurons in few brain regions, activate glutamate receptors, decrease glutamate receptor's expression, impair glutamate-induced signaling and function, activate blood brain barrier endothelial cells, kill neurons, damage the brain, induce behavioral/psychiatric/cognitive abnormalities and ataxia in animal models, and can be removed or silenced in some patients by immunotherapy.

    Science.gov (United States)

    Levite, Mia

    2014-08-01

    Glutamate is the major excitatory neurotransmitter of the Central Nervous System (CNS), and it is crucially needed for numerous key neuronal functions. Yet, excess glutamate causes massive neuronal death and brain damage by excitotoxicity--detrimental over activation of glutamate receptors. Glutamate-mediated excitotoxicity is the main pathological process taking place in many types of acute and chronic CNS diseases and injuries. In recent years, it became clear that not only excess glutamate can cause massive brain damage, but that several types of anti-glutamate receptor antibodies, that are present in the serum and CSF of subpopulations of patients with a kaleidoscope of human neurological diseases, can undoubtedly do so too, by inducing several very potent pathological effects in the CNS. Collectively, the family of anti-glutamate receptor autoimmune antibodies seem to be the most widespread, potent, dangerous and interesting anti-brain autoimmune antibodies discovered up to now. This impression stems from taking together the presence of various types of anti-glutamate receptor antibodies in a kaleidoscope of human neurological and autoimmune diseases, their high levels in the CNS due to intrathecal production, their multiple pathological effects in the brain, and the unique and diverse mechanisms of action by which they can affect glutamate receptors, signaling and effects, and subsequently impair neuronal signaling and induce brain damage. The two main families of autoimmune anti-glutamate receptor antibodies that were already found in patients with neurological and/or autoimmune diseases, and that were already shown to be detrimental to the CNS, include the antibodies directed against ionotorpic glutamate receptors: the anti-AMPA-GluR3 antibodies, anti-NMDA-NR1 antibodies and anti-NMDA-NR2 antibodies, and the antibodies directed against Metabotropic glutamate receptors: the anti-mGluR1 antibodies and the anti-mGluR5 antibodies. Each type of these anti

  20. Agricultural non-point source pollution of glyphosate and AMPA at a catchment scale

    Science.gov (United States)

    Okada, Elena; Perez, Debora; De Geronimo, Eduardo; Aparicio, Virginia; Costa, Jose Luis

    2017-04-01

    can be attributed to deposition of soil particles that are washed from the field. On the other hand, more than 90 % of the soil samples had glyphosate and AMPA. The highest concentrations were found in the month of June, corresponding to the fallow period were glyphosate is applied as a chemical weed controller in no-till systems. Glyphosate and AMPA detection in groundwater samples was 24% and 35%, respectively. The highest glyphosate levels in groundwater also corresponded to the month of June. Glyphosate occurrence in groundwater was transient, that is, in most of the cases glyphosate was not detected in the subsequent sampling months. The contamination of shallow groundwater (application, that may contribute to groundwater contamination. This is of extreme relevance in the southeast of the Buenos Aires Province, since the main source of drinking water and irrigation is from groundwater resources

  1. Karakterisasi Kemasan Kertas Aktif dengan Penambahan Oleoresin Ampas Destilasi Sereh Dapur (Cymbopogon citratus

    Directory of Open Access Journals (Sweden)

    Lia Umi Khasanah

    2017-03-01

    Full Text Available The aims of this research were to determine the effect of lemongrass distillation dregs oleoresin concentration (0 %, 2 %, 4 %, and 6 % b/b on the active paper packaging characteristics (sensory, water content, thickness, tensile strength, fold endurance and antimicrobial activity, to determine the functional groups of the control and selected active paper packaging, to determine the effect of days of storage (0, 5, 10, 15, and 20 day on the control and selected active paper packaging characteristics (tensile strength, and fold endurance, and to determine antimicrobial activity of the control and selected active paper packaging during 20 days storage. The result showed that the concentration of lemongrass distillation dregs oleoresin significantly affected the color, overall, tensile strength, fold endurance, and antimicrobial activity while did not significantly affected the flavor, texture, water content, and thickness of the active paper packaging. The addition of lemongrass distillation dregs oleoresin increased the water content, thickness, microbial activity, while decreased the panelists preference, tensile strength and fold endurance of the active paper packaging. The spectrum of functional groups of the active paper packaging showed the presence of chitosan, cellulose, tween 80, and lemongrass oleoresin. The storage days had no significant effect on tensile strength and fold endurance of the control and selected active paper packaging. The control and selected active paper packaging were significantly different at each 5 days storage. However the 20 day of storage showed no significant effect on the antimicrobial activity of the control and selected active paper packaging.   ABSTRAK Tujuan dari penelitian ini adalah untuk mengetahui pengaruh konsentrasi oleoresin ampas destilasi sereh dapur (0 %, 2 %, 4 %, dan 6 % b/b terhadap karakteristik kemasan kertas aktif (analisis sensoris, kadar air, ketebalan, ketahanan tarik, ketahanan lipat

  2. Tetrazolyl isoxazole amino acids as ionotropic glutamate receptor antagonists: synthesis, modelling and molecular pharmacology

    DEFF Research Database (Denmark)

    Frølund, Bente; Greenwood, Jeremy R; Holm, Mai Marie

    2005-01-01

    and 1b were pharmacologically characterized in receptor binding assays, and electrophysiologically on homomeric AMPA receptors (GluR1-4), homomeric (GluR5 and GluR6) and heteromeric (GluR6/KA2) kainic acid receptors, using two-electrode voltage-clamped Xenopus laevis oocytes expressing these receptors...

  3. The MC4 receptor and control of appetite

    NARCIS (Netherlands)

    Adan, R. A. H.; Tiesjema, B.; Hillebrand, J. J. G.; La Fleur, S. E.; Kas, M. J. H.; de Krom, M.

    2006-01-01

    Mutations in the human melanocortin (MC)4 receptor have been associated with obesity, which underscores the relevance of this receptor as a drug target to treat obesity. Infusion of MC4R agonists decreases food intake, whereas inhibition of MC receptor activity by infusion of an MC receptor

  4. CDKL5 controls postsynaptic localization of GluN2B-containing NMDA receptors in the hippocampus and regulates seizure susceptibility.

    Science.gov (United States)

    Okuda, Kosuke; Kobayashi, Shizuka; Fukaya, Masahiro; Watanabe, Aya; Murakami, Takuto; Hagiwara, Mai; Sato, Tempei; Ueno, Hiroe; Ogonuki, Narumi; Komano-Inoue, Sayaka; Manabe, Hiroyuki; Yamaguchi, Masahiro; Ogura, Atsuo; Asahara, Hiroshi; Sakagami, Hiroyuki; Mizuguchi, Masashi; Manabe, Toshiya; Tanaka, Teruyuki

    2017-10-01

    Mutations in the Cyclin-dependent kinase-like 5 (CDKL5) gene cause severe neurodevelopmental disorders accompanied by intractable epilepsies, i.e. West syndrome or atypical Rett syndrome. Here we report generation of the Cdkl5 knockout mouse and show that CDKL5 controls postsynaptic localization of GluN2B-containing N-methyl-d-aspartate (NMDA) receptors in the hippocampus and regulates seizure susceptibility. Cdkl5 -/Y mice showed normal sensitivity to kainic acid; however, they displayed significant hyperexcitability to NMDA. In concordance with this result, electrophysiological analysis in the hippocampal CA1 region disclosed an increased ratio of NMDA/α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-mediated excitatory postsynaptic currents (EPSCs) and a significantly larger decay time constant of NMDA receptor-mediated EPSCs (NMDA-EPSCs) as well as a stronger inhibition of the NMDA-EPSCs by the GluN2B-selective antagonist ifenprodil in Cdkl5 -/Y mice. Subcellular fractionation of the hippocampus from Cdkl5 -/Y mice revealed a significant increase of GluN2B and SAP102 in the PSD (postsynaptic density)-1T fraction, without changes in the S1 (post-nuclear) fraction or mRNA transcripts, indicating an intracellular distribution shift of these proteins to the PSD. Immunoelectron microscopic analysis of the hippocampal CA1 region further confirmed postsynaptic overaccumulation of GluN2B and SAP102 in Cdkl5 -/Y mice. Furthermore, ifenprodil abrogated the NMDA-induced hyperexcitability in Cdkl5 -/Y mice, suggesting that upregulation of GluN2B accounts for the enhanced seizure susceptibility. These data indicate that CDKL5 plays an important role in controlling postsynaptic localization of the GluN2B-SAP102 complex in the hippocampus and thereby regulates seizure susceptibility, and that aberrant NMDA receptor-mediated synaptic transmission underlies the pathological mechanisms of the CDKL5 loss-of-function. Copyright © 2017 Elsevier Inc. All rights

  5. Role of Peroxisome Proliferator-Activated Receptors in Inflammation Control

    Directory of Open Access Journals (Sweden)

    Jihan Youssef

    2004-01-01

    Full Text Available Peroxisome proliferator-activated receptors (PPARs were discovered over a decade ago, and were classified as orphan members of the nuclear receptor superfamily. To date, three PPAR subtypes have been discovered and characterized (PPARα, β/δ, γ. Different PPAR subtypes have been shown to play crucial roles in important diseases and conditions such as obesity, diabetes, atherosclerosis, cancer, and fertility. Among the most studied roles of PPARs is their involvement in inflammatory processes. Numerous studies have revealed that agonists of PPARα and PPARγ exert anti-inflammatory effects both in vitro and in vivo. Using the carrageenan-induced paw edema model of inflammation, a recent study in our laboratories showed that these agonists hinder the initiation phase, but not the late phase of the inflammatory process. Furthermore, in the same experimental model, we recently also observed that activation of PPARδ exerted an anti-inflammatory effect. Despite the fact that exclusive dependence of these effects on PPARs has been questioned, the bulk of evidence suggests that all three PPAR subtypes, PPARα,δ,γ, play a significant role in controlling inflammatory responses. Whether these subtypes act via a common mechanism or are independent of each other remains to be elucidated. However, due to the intensity of research efforts in this area, it is anticipated that these efforts will result in the development of PPAR ligands as therapeutic agents for the treatment of inflammatory diseases.

  6. Novel quinolinone-phosphonic acid AMPA antagonists devoid of nephrotoxicity.

    Science.gov (United States)

    Cordi, Alex A; Desos, Patrice; Ruano, Elisabeth; Al-Badri, Hashim; Fugier, Claude; Chapman, Astrid G; Meldrum, Brian S; Thomas, Jean-Yves; Roger, Anita; Lestage, Pierre

    2002-10-01

    We reported previously the synthesis and structure-activity relationships (SAR) in a series of 2-(1H)-oxoquinolines bearing different acidic functions in the 3-position. Exploiting these SAR, we were able to identify 6,7-dichloro-2-(1H)-oxoquinoline-3-phosphonic acid compound 3 (S 17625) as a potent, in vivo active AMPA antagonist. Unfortunately, during the course of the development, nephrotoxicity was manifest at therapeutically effective doses. Considering that some similitude exists between S 17625 and probenecid, a compound known to protect against the nephrotoxicity and/or slow the clearance of different drugs, we decided to synthesise some new analogues of S 17625 incorporating some of the salient features of probenecid. Replacement of the chlorine in position 6 by a sulfonylamine led to very potent AMPA antagonists endowed with good in vivo activity and lacking nephrotoxicity potential. Amongst the compounds evaluated, derivatives 7a and 7s appear to be the most promising and are currently evaluated in therapeutically relevant stroke models.

  7. Control of Transcriptional Repression of the Vitellogenin Receptor Gene in Largemouth Bass (Micropterus Salmoides) by Select Estrogen Receptors Isotypes

    OpenAIRE

    Dominguez, Gustavo A.; Bisesi, Joseph H.; Kroll, Kevin J.; Denslow, Nancy D.; Sabo-Attwood, Tara

    2014-01-01

    The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor functions to incorporate vitellogenin (Vtg), a macromolecule synthesized and released from the liver in the bloodstream, into oocytes where it is processed into yolk. Although studies have focused on the functional role of Vtgr in fish, the mechanistic control of this gene is still unexplored. Here we report the identification and analysis of the first piscine 5′ regulatory region of the vtgr gene whi...

  8. The different behaviors of glyphosate and AMPA in compost-amended soil.

    Science.gov (United States)

    Erban, Tomas; Stehlik, Martin; Sopko, Bruno; Markovic, Martin; Seifrtova, Marcela; Halesova, Tatana; Kovaricek, Pavel

    2018-05-04

    The broad-spectrum herbicide glyphosate is one of the most widely used pesticides. Both glyphosate and its major metabolite, aminomethylphosphonic acid (AMPA), persist in waters; thus, their environmental fates are of interest. We investigated the influence of compost dose, sampling depth, moisture and saturated hydraulic conductivity (K s ) on the persistence of these substances. The amounts of AMPA quantified by triple quadrupole liquid chromatography-mass spectrometry (LC-QqQ-MS/MS) using isotopically labeled extraction standards were higher than those of glyphosate and differed among the samples. Both glyphosate and AMPA showed gradually decreasing concentrations with soil depth, and bootstrapped ANOVA showed significant differences between the contents of glyphosate and AMPA and their behavior related to different compost dosages and sampling depths. However, the compost dose alone did not cause significant differences among samples. Bayesian statistics revealed that the amounts of glyphosate and AMPA were both dependent on the sampling depth and compost dose, but differences were found when considering the physical factors of K s and moisture. Glyphosate was influenced by moisture but not K s , whereas AMPA was influenced by K s but not moisture. Importantly, we found behavioral differences between glyphosate and its major metabolite, AMPA, related to the physical properties of K s and moisture. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. PENGGUNAAN KARBON AKTIF DARI AMPAS TEBU SEBAGAI ADSORBEN ZAT WARNA PROCION MERAH DARI INDUSTRI SONGKET

    Directory of Open Access Journals (Sweden)

    Melyza Fitri Permanda Sari

    2017-04-01

    Full Text Available Telah dilakukan penelitian penggunaan karbon aktif dari ampas tebu untuk menyerap zat warna procion merah dari industri songket. Pembuatan karbon aktif dilakukan dengan proses karbonisasi pada temperatur 4500C selama 2 jam, karbon aktif yang dihasilkan dilakukan karakterisasi FTIR untuk mengetahui gugus fungsinya serta karakterisasi BET untuk mengetahui luas permukan. Kondisi optimum adsorpsi karbon aktif dari ampas tebu terhadap procion merah dilakukan dengan beberapa variabel, meliputi waktu kontak, berat karbon aktif, dan pH. Hasil karakterisasi FTIR pada karbon aktif dari ampas tebu memiliki gugus fungsi -CO- dan –OH, sedangkan karakterisasi BET karbon aktif dari ampas tebu sebesar 29,2 m2/g. Kondisi optimum adsorpsi karbon aktif dari ampas tebu diperoleh waktu kontak 90 menit dengan berat karbon aktif 0,1 g dan pH optimum 5. Karbon aktif dari ampas tebu mengikuti isotherm Langmuir, efektifitas penyerapan zat warna procion merah dari limbah cair industri songket oleh karbon aktif dari ampas tebu dalam kondisi optimum, sebesar 76,3%.

  10. Glyphosate and AMPA inhibit cancer cell growth through inhibiting intracellular glycine synthesis.

    Science.gov (United States)

    Li, Qingli; Lambrechts, Mark J; Zhang, Qiuyang; Liu, Sen; Ge, Dongxia; Yin, Rutie; Xi, Mingrong; You, Zongbing

    2013-01-01

    Glycine is a nonessential amino acid that is reversibly converted from serine intracellularly by serine hydroxymethyltransferase. Glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), are analogs to glycine, thus they may inhibit serine hydroxymethyltransferase to decrease intracellular glycine synthesis. In this study, we found that glyphosate and AMPA inhibited cell growth in eight human cancer cell lines but not in two immortalized human normal prostatic epithelial cell lines. AMPA arrested C4-2B and PC-3 cancer cells in the G1/G0 phase and inhibited entry into the S phase of the cell cycle. AMPA also promoted apoptosis in C4-2B and PC-3 cancer cell lines. AMPA upregulated p53 and p21 protein levels as well as procaspase 9 protein levels in C4-2B cells, whereas it downregulated cyclin D3 protein levels. AMPA also activated caspase 3 and induced cleavage of poly (adenosine diphosphate [ADP]-ribose) polymerase. This study provides the first evidence that glyphosate and AMPA can inhibit proliferation and promote apoptosis of cancer cells but not normal cells, suggesting that they have potentials to be developed into a new anticancer therapy.

  11. The meth brain: methamphetamines alter brain functions via NMDA receptors

    Czech Academy of Sciences Publication Activity Database

    Proft, Juliane; Weiss, Norbert

    2015-01-01

    Roč. 34, č. 1 (2015), s. 1-3 ISSN 0231-5882 R&D Projects: GA ČR GA15-13556S Institutional support: RVO:61388963 Keywords : ion channel * methamphetamine * piriform cortex * NMDA receptor * AMPA receptor Subject RIV: CE - Biochemistry Impact factor: 0.892, year: 2015

  12. An investigation of interactions between hypocretin/orexin signaling and glutamate receptor surface expression in the rat nucleus accumbens under basal conditions and after cocaine exposure.

    Science.gov (United States)

    Plaza-Zabala, Ainhoa; Li, Xuan; Milovanovic, Mike; Loweth, Jessica A; Maldonado, Rafael; Berrendero, Fernando; Wolf, Marina E

    2013-12-17

    Hypocretin peptides are critical for the effects of cocaine on excitatory synaptic strength in the ventral tegmental area (VTA). However, little is known about their role in cocaine-induced synaptic plasticity in the nucleus accumbens (NAc). First, we tested whether hypocretin-1 by itself could acutely modulate glutamate receptor surface expression in the NAc, given that hypocretin-1 in the VTA reproduces cocaine's effects on glutamate transmission. We found no effect of hypocretin-1 infusion on AMPA or NMDA receptor surface expression in the NAc, measured by biotinylation, either 30 min or 3h after the infusion. Second, we were interested in whether changes in hypocretin receptor-2 (Hcrtr-2) expression contribute to cocaine-induced plasticity in the NAc. As a first step towards addressing this question, Hcrtr-2 surface expression was compared in the NAc after withdrawal from extended-access self-administration of saline (control) versus cocaine. We found that surface Hcrtr-2 levels remain unchanged following 14, 25 or 48 days of withdrawal from cocaine, a time period in which high conductance GluA2-lacking AMPA receptors progressively emerge in the NAc. Overall, our results fail to support a role for hypocretins in acute modulation of glutamate receptor levels in the NAc or a role for altered Hcrtr-2 expression in withdrawal-dependent synaptic adaptations in the NAc following cocaine self-administration. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. AMPA: an automated web server for prediction of protein antimicrobial regions.

    Science.gov (United States)

    Torrent, Marc; Di Tommaso, Paolo; Pulido, David; Nogués, M Victòria; Notredame, Cedric; Boix, Ester; Andreu, David

    2012-01-01

    AMPA is a web application for assessing the antimicrobial domains of proteins, with a focus on the design on new antimicrobial drugs. The application provides fast discovery of antimicrobial patterns in proteins that can be used to develop new peptide-based drugs against pathogens. Results are shown in a user-friendly graphical interface and can be downloaded as raw data for later examination. AMPA is freely available on the web at http://tcoffee.crg.cat/apps/ampa. The source code is also available in the web. marc.torrent@upf.edu; david.andreu@upf.edu Supplementary data are available at Bioinformatics online.

  14. Gating characteristics control glutamate receptor distribution and trafficking in vivo.

    Science.gov (United States)

    Petzoldt, Astrid G; Lee, Yü-Hien; Khorramshahi, Omid; Reynolds, Eric; Plested, Andrew J R; Herzel, Hanspeter; Sigrist, Stephan J

    2014-09-08

    Glutamate-releasing synapses dominate excitatory release in the brain. Mechanisms governing their assembly are of major importance for circuit development and long-term plasticity underlying learning and memory. AMPA/Kainate-type glutamate receptors (GluRs) are tetrameric ligand-gated ion channels that open their ion-conducting pores in response to binding of the neurotransmitter. Changes in subunit composition of postsynaptic GluRs are highly relevant for plasticity and development of glutamatergic synapses [1-4]. To date, posttranslational modifications, mostly operating via the intracellular C-terminal domains (CTDs) of GluRs, are presumed to be the major regulator of trafficking [5]. In recent years, structural and electrophysiological analyses have improved our understanding of GluR gating mechanism [6-11]. However, whether conformational changes subsequent to glutamate binding may per se be able to influence GluR trafficking has remained an unaddressed question. Using a Drosophila system allowing for extended visualization of GluR trafficking in vivo, we here provide evidence that mutations changing the gating behavior alter GluR distribution and trafficking. GluR mutants associated with reduced charge transfer segregated from coexpressed wild-type GluRs on the level of individual postsynaptic densities. Segregation was lost upon blocking of evoked glutamate release. Photobleaching experiments suggested increased mobility of mutants with reduced charge transfer, which accumulated prematurely during early steps of synapse assembly, but failed to further increase their level in accordance with assembly of the presynaptic scaffold. In summary, gating characteristics seem to be a new variable for the understanding of GluR trafficking relevant to both development and plasticity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Hormonal control of spermatogenesis: expression of FSJH receptor and androgen receptor genes

    NARCIS (Netherlands)

    L.J. Blok (Leen)

    1992-01-01

    textabstractFSH and testosterone are the main hormonal regulators of spermatogenesis. The actions of androgens and FSH are mediated by their respective receptors. Receptor gene expression (mRNA and protein). is an important determinant of hormone action. Biochemical aspects of the regulation of

  16. The nuclear receptor NR2E1/TLX controls senescence

    Science.gov (United States)

    Krusche, Benjamin; Pemberton, Helen; Alonso, Marta M.; Chandler, Hollie; Brookes, Sharon; Parrinello, Simona; Peters, Gordon; Gil, Jesús

    2014-01-01

    The nuclear receptor NR2E1 (also known as TLX or tailless) controls the self-renewal of neural stem cells (NSCs) and has been implied as an oncogene which initiates brain tumours including glioblastomas. Despite NR2E1 regulating targets like p21CIP1 or PTEN we still lack a full explanation for its role in NSC self-renewal and tumorigenesis. We know that Polycomb repressive complexes (PRC) also control stem cell self-renewal and tumorigenesis, but so far, no formal connection has been established between NR2E1 and PRCs. In a screen for transcription factors regulating the expression of the Polycomb protein CBX7, we identified NR2E1 as one of its more prominent regulators. NR2E1 binds at the CBX7 promoter, inducing its expression. Notably CBX7 represses NR2E1 as part of a regulatory loop. Ectopic NR2E1 expression inhibits cellular senescence, extending cellular lifespan in fibroblasts via CBX7-mediated regulation of p16INK4a and direct repression of p21CIP1. In addition NR2E1 expression also counteracts oncogene-induced senescence (OIS). The importance of NR2E1 to restrain senescence is highlighted through the process of knocking down its expression, which causes premature senescence in human fibroblasts and epithelial cells. We also confirmed that NR2E1 regulates CBX7 and restrains senescence in NSCs. Finally, we observed that the expression of NR2E1 directly correlates with that of CBX7 in human glioblastoma multiforme. Overall we identified control of senescence and regulation of Polycomb action as two possible mechanisms that can join those so far invoked to explain the role of NR2E1 in control of NSC self-renewal and cancer. PMID:25328137

  17. The nuclear receptor NR2E1/TLX controls senescence.

    Science.gov (United States)

    O'Loghlen, Ana; Martin, Nadine; Krusche, Benjamin; Pemberton, Helen; Alonso, Marta M; Chandler, Hollie; Brookes, Sharon; Parrinello, Simona; Peters, Gordon; Gil, Jesús

    2015-07-30

    The nuclear receptor NR2E1 (also known as TLX or tailless) controls the self-renewal of neural stem cells (NSCs) and has been implied as an oncogene which initiates brain tumors including glioblastomas. Despite NR2E1 regulating targets like p21(CIP1) or PTEN we still lack a full explanation for its role in NSC self-renewal and tumorigenesis. We know that polycomb repressive complexes also control stem cell self-renewal and tumorigenesis, but so far, no formal connection has been established between NR2E1 and PRCs. In a screen for transcription factors regulating the expression of the polycomb protein CBX7, we identified NR2E1 as one of its more prominent regulators. NR2E1 binds at the CBX7 promoter, inducing its expression. Notably CBX7 represses NR2E1 as part of a regulatory loop. Ectopic NR2E1 expression inhibits cellular senescence, extending cellular lifespan in fibroblasts via CBX7-mediated regulation of p16(INK4a) and direct repression of p21(CIP1). In addition NR2E1 expression also counteracts oncogene-induced senescence. The importance of NR2E1 to restrain senescence is highlighted through the process of knocking down its expression, which causes premature senescence in human fibroblasts and epithelial cells. We also confirmed that NR2E1 regulates CBX7 and restrains senescence in NSCs. Finally, we observed that the expression of NR2E1 directly correlates with that of CBX7 in human glioblastoma multiforme. Overall we identified control of senescence and regulation of polycomb action as two possible mechanisms that can join those so far invoked to explain the role of NR2E1 in control of NSC self-renewal and cancer.

  18. Secretory phospholipase A2-mediated neuronal cell death involves glutamate ionotropic receptors

    DEFF Research Database (Denmark)

    Kolko, Miriam; de Turco, Elena B; Diemer, Nils Henrik

    2002-01-01

    To define the significance of glutamate ionotropic receptors in sPLA -mediated neuronal cell death we used the NMDA receptor antagonist MK-801 and the AMPA receptor antagonist PNQX. In primary neuronal cell cultures both MK-801 and PNQX inhibited sPLA - and glutamate-induced neuronal death. [ H...

  19. Novel Functional Properties of Drosophila CNS Glutamate Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan; Dharkar, Poorva; Han, Tae-Hee; Serpe, Mihaela; Lee, Chi-Hon; Mayer, Mark L.

    2016-12-01

    Phylogenetic analysis reveals AMPA, kainate, and NMDA receptor families in insect genomes, suggesting conserved functional properties corresponding to their vertebrate counterparts. However, heterologous expression of the Drosophila kainate receptor DKaiR1D and the AMPA receptor DGluR1A revealed novel ligand selectivity at odds with the classification used for vertebrate glutamate receptor ion channels (iGluRs). DKaiR1D forms a rapidly activating and desensitizing receptor that is inhibited by both NMDA and the NMDA receptor antagonist AP5; crystallization of the KaiR1D ligand-binding domain reveals that these ligands stabilize open cleft conformations, explaining their action as antagonists. Surprisingly, the AMPA receptor DGluR1A shows weak activation by its namesake agonist AMPA and also by quisqualate. Crystallization of the DGluR1A ligand-binding domain reveals amino acid exchanges that interfere with binding of these ligands. The unexpected ligand-binding profiles of insect iGluRs allows classical tools to be used in novel approaches for the study of synaptic regulation.

  20. Pembuatan dan Pengujian Kualitas Semen Portland Yang Diperkaya Silikat Abu Ampas Tebu

    OpenAIRE

    Suci Wulandari, Indah Pratama

    2015-01-01

    Penelitian ini mengkaji pengaruh penambahan abu ampas tebu terhadap kuat tekan mortar dan sifat fisis semen portland komposit, meliputi: kehalusan semen, kebutuhan air semen, waktu pengikatan semen, pemuaian dan komposisi kimia semen. Dari hasil penelitian, besar kuat tekan pada penggunaan abu ampas tebu dengan kadar 9% merupakan penambahan optimum pada mortar yang direndam larutan kapur jenuh Sedangkan dari hasil pengujian fisis yang meliputi kehalusan semen, kebutuhan air semen, waktu pengi...

  1. Differential effects of glyphosate and aminomethylphosphonic acid (AMPA) on photosynthesis and chlorophyll metabolism in willow plants.

    Science.gov (United States)

    Gomes, Marcelo Pedrosa; Le Manac'h, Sarah Gingras; Maccario, Sophie; Labrecque, Michel; Lucotte, Marc; Juneau, Philippe

    2016-06-01

    We used a willow species (Salix miyabeana cultivar SX64) to examine the differential secondary-effects of glyphosate and aminomethylphosphonic acid (AMPA), the principal glyphosate by-product, on chlorophyll metabolism and photosynthesis. Willow plants were treated with different concentrations of glyphosate (equivalent to 0, 1.4, 2.1 and 2.8kgha(-1)) and AMPA (equivalent to 0, 0.28, 1.4 and 2.8kgha(-1)) and evaluations of pigment contents, chlorophyll fluorescence, and oxidative stress markers (hydrogen peroxide content and antioxidant enzyme activities) in leaves were performed after 12h of exposure. We observed that AMPA and glyphosate trigger different mechanisms leading to decreases in chlorophyll content and photosynthesis rates in willow plants. Both chemicals induced ROS accumulation in willow leaves although only glyphosate-induced oxidative damage through lipid peroxidation. By disturbing chlorophyll biosynthesis, AMPA induced decreases in chlorophyll contents, with consequent effects on photosynthesis. With glyphosate, ROS increases were higher than the ROS-sensitive threshold, provoking chlorophyll degradation (as seen by pheophytin accumulation) and invariable decreases in photosynthesis. Peroxide accumulation in both AMPA and glyphosate-treated plants was due to the inhibition of antioxidant enzyme activities. The different effects of glyphosate on chlorophyll contents and photosynthesis as described in the literature may be due to various glyphosate:AMPA ratios in those plants. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. N1-Substituted 2,3-Quinoxalinediones as Kainate Receptor Antagonists: X-ray Crystallography, Structure-Affinity Relationships and in vitro Pharmacology

    DEFF Research Database (Denmark)

    Pallesen, Jakob Staun; Møllerud, Stine; Frydenvang, Karla Andrea

    2018-01-01

    Among the ionotropic glutamate receptors, the physiological role of kainate receptors is less well understood than AMPA and NMDA receptors, partly due to a lack of selective pharmacological tool compounds. Although ligands with selectivity towards the kainate receptor subtype GluK1 are available,...

  3. Glyphosate-Resistant and Conventional Canola (Brassica napus L.) Responses to Glyphosate and Aminomethylphosphonic Acid (AMPA) Treatment.

    Science.gov (United States)

    Corrêa, Elza Alves; Dayan, Franck E; Owens, Daniel K; Rimando, Agnes M; Duke, Stephen O

    2016-05-11

    Glyphosate-resistant (GR) canola contains two transgenes that impart resistance to the herbicide glyphosate: (1) the microbial glyphosate oxidase gene (gox) encoding the glyphosate oxidase enzyme (GOX) that metabolizes glyphosate to aminomethylphosphonic acid (AMPA) and (2) cp4 that encodes a GR form of the glyphosate target enzyme 5-enolpyruvylshikimic acid-3-phosphate synthase. The objectives of this research were to determine the phytotoxicity of AMPA to canola, the relative metabolism of glyphosate to AMPA in GR and conventional non-GR (NGR) canola, and AMPA pool sizes in glyphosate-treated GR canola. AMPA applied at 1.0 kg ha(-1) was not phytotoxic to GR or NGR. At this AMPA application rate, NGR canola accumulated a higher concentration of AMPA in its tissues than GR canola. At rates of 1 and 3.33 kg ae ha(-1) of glyphosate, GR canola growth was stimulated. This stimulatory effect is similar to that of much lower doses of glyphosate on NGR canola. Both shikimate and AMPA accumulated in tissues of these glyphosate-treated plants. In a separate experiment in which young GR and NGR canola plants were treated with non-phytotoxic levels of [(14)C]-glyphosate, very little glyphosate was metabolized in NGR plants, whereas most of the glyphosate was metabolized to AMPA in GR plants at 7 days after application. Untreated leaves of GR plants accumulated only metabolites (mostly AMPA) of glyphosate, indicating that GOX activity is very high in the youngest leaves. These data indicate that more glyphosate is transformed to AMPA rapidly in GR canola and that the accumulated AMPA is not toxic to the canola plant.

  4. Presynaptic Ionotropic Receptors Controlling and Modulating the Rules for Spike Timing-Dependent Plasticity

    Directory of Open Access Journals (Sweden)

    Matthijs B. Verhoog

    2011-01-01

    Full Text Available Throughout life, activity-dependent changes in neuronal connection strength enable the brain to refine neural circuits and learn based on experience. In line with predictions made by Hebb, synapse strength can be modified depending on the millisecond timing of action potential firing (STDP. The sign of synaptic plasticity depends on the spike order of presynaptic and postsynaptic neurons. Ionotropic neurotransmitter receptors, such as NMDA receptors and nicotinic acetylcholine receptors, are intimately involved in setting the rules for synaptic strengthening and weakening. In addition, timing rules for STDP within synapses are not fixed. They can be altered by activation of ionotropic receptors located at, or close to, synapses. Here, we will highlight studies that uncovered how network actions control and modulate timing rules for STDP by activating presynaptic ionotropic receptors. Furthermore, we will discuss how interaction between different types of ionotropic receptors may create “timing” windows during which particular timing rules lead to synaptic changes.

  5. Glyphosate and AMPA inhibit cancer cell growth through inhibiting intracellular glycine synthesis

    Directory of Open Access Journals (Sweden)

    Li Q

    2013-07-01

    Full Text Available Qingli Li,1,2 Mark J Lambrechts,1 Qiuyang Zhang,1 Sen Liu,1 Dongxia Ge,1 Rutie Yin,2 Mingrong Xi,2 Zongbing You1 1Departments of Structural and Cellular Biology and Orthopaedic Surgery, Tulane Cancer Center and Louisiana Cancer Research Consortium, Tulane Center for Stem Cell Research and Regenerative Medicine, and Tulane Center for Aging, Tulane University Health Sciences Center, New Orleans, LA, USA; 2Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, People’s Republic of China Abstract: Glycine is a nonessential amino acid that is reversibly converted from serine intracellularly by serine hydroxymethyltransferase. Glyphosate and its degradation product, aminomethylphosphonic acid (AMPA, are analogs to glycine, thus they may inhibit serine hydroxymethyltransferase to decrease intracellular glycine synthesis. In this study, we found that glyphosate and AMPA inhibited cell growth in eight human cancer cell lines but not in two immortalized human normal prostatic epithelial cell lines. AMPA arrested C4-2B and PC-3 cancer cells in the G1/G0 phase and inhibited entry into the S phase of the cell cycle. AMPA also promoted apoptosis in C4-2B and PC-3 cancer cell lines. AMPA upregulated p53 and p21 protein levels as well as procaspase 9 protein levels in C4-2B cells, whereas it downregulated cyclin D3 protein levels. AMPA also activated caspase 3 and induced cleavage of poly (adenosine diphosphate [ADP]-ribose polymerase. This study provides the first evidence that glyphosate and AMPA can inhibit proliferation and promote apoptosis of cancer cells but not normal cells, suggesting that they have potentials to be developed into a new anticancer therapy. Keywords: serine hydroxymethyltransferase, prostate cancer, apoptosis

  6. [Effects of GLP-1 receptor agonists on carbohydrate metabolism control].

    Science.gov (United States)

    Fernández-García, José Carlos; Colomo, Natalia; Tinahones, Francisco José

    2014-09-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are a new group of drugs for the treatment of type 2 diabetes mellitus (DM2). In the present article, we review the available evidence on the efficacy of GLP-1 receptor agonists as glucose-lowering agents, their place in therapeutic algorithms, and the clinical factors associated with a favorable treatment response. Finally, we describe the clinical characteristics of patients who may benefit from these drugs. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  7. Biostructural and pharmacological studies of bicyclic analogues of the 3-isoxazolol glutamate receptor agonist ibotenic acid

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Pickering, Darryl S; Greenwood, Jeremy R

    2010-01-01

    We describe an improved synthesis and detailed pharmacological characterization of the conformationally restricted analogue of the naturally occurring nonselective glutamate receptor agonist ibotenic acid (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-7-carboxylic acid (7-HPCA, 5......) at AMPA receptor subtypes. Compound 5 was shown to be a subtype-discriminating agonist at AMPA receptors with higher binding affinity and functional potency at GluA1/2 compared to GluA3/4, unlike the isomeric analogue (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-5-carboxylic acid (5-HPCA, 4...

  8. Protein kinase C alpha controls erythropoietin receptor signaling.

    NARCIS (Netherlands)

    M.M. von Lindern (Marieke); M. Parren-Van Amelsvoort (Martine); T.B. van Dijk (Thamar); E. Deiner; B. Löwenberg (Bob); E. van den Akker (Emile); S. van Emst-de Vries (Sjenet); P.J. Willems (Patrick); H. Beug (Hartmut)

    2000-01-01

    textabstractProtein kinase C (PKC) is implied in the activation of multiple targets of erythropoietin (Epo) signaling, but its exact role in Epo receptor (EpoR) signal transduction and in the regulation of erythroid proliferation and differentiation remained elusive. We

  9. Protein kinase C alpha controls erythropoietin receptor signaling

    NARCIS (Netherlands)

    von Lindern, M.; Parren-van Amelsvoort, M.; van Dijk, T.; Deiner, E.; van den Akker, E.; van Emst-de Vries, S.; Willems, P.; Beug, H.; Löwenberg, B.

    2000-01-01

    Protein kinase C (PKC) is implied in the activation of multiple targets of erythropoietin (Epo) signaling, but its exact role in Epo receptor (EpoR) signal transduction and in the regulation of erythroid proliferation and differentiation remained elusive. We analyzed the effect of PKC inhibitors

  10. β-arrestins negatively control human adrenomedullin type 1-receptor internalization

    International Nuclear Information System (INIS)

    Kuwasako, Kenji; Kitamura, Kazuo; Nagata, Sayaka; Sekiguchi, Toshio; Danfeng, Jiang; Murakami, Manabu; Hattori, Yuichi; Kato, Johji

    2017-01-01

    Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM 1 receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM 1 receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β 2 -adrenergic receptor (β 2 -AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [ 125 I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM 1 receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM 1 receptor internalization. In contrast, the AM-induced internalization of the chimeric AM 1 receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β 2 -AR. Thus, both β-arrs negatively control AM 1 receptor internalization, which depends on the C-tail of CLR. - Highlights: • We found that β-arrestins 1 and 2 negatively control agonist-induced GPCR internalization. • β-arrestins 1 and 2 significantly inhibits the AM

  11. Transfer of glyphosate and its degradate AMPA to surface waters through urban sewerage systems.

    Science.gov (United States)

    Botta, Fabrizio; Lavison, Gwenaëlle; Couturier, Guillaume; Alliot, Fabrice; Moreau-Guigon, Elodie; Fauchon, Nils; Guery, Bénédicte; Chevreuil, Marc; Blanchoud, Hélène

    2009-09-01

    A study of glyphosate and aminomethyl phosphonic acid (AMPA) transfer in the Orge watershed (France) was carried out during 2007 and 2008. Water samples were collected in surface water, wastewater sewer, storm sewer and wastewater treatment plant (WWTP). These two molecules appeared to be the most frequently detected ones in the rivers and usually exceeded the European quality standard concentrations of 0.1microg L(-1) for drinking water. The annual glyphosate estimated load was 1.9 kg year(-1) upstream (agricultural zone) and 179.5 kg year(-1) at the catchment outlet (urban zone). This result suggests that the contamination of this basin by glyphosate is essentially from urban origin (road and railway applications). Glyphosate reached surface water prevalently through storm sewer during rainfall event. Maximum concentrations were detected in storm sewer just after a rainfall event (75-90 microg L(-1)). High concentrations of glyphosate in surface water during rainfall events reflected urban runoff impact. AMPA was always detected in the sewerage system. This molecule reached surface water mainly via WWTP effluent and also through storm sewer. Variations in concentrations of AMPA during hydrological episodes were minor compared to glyphosate variations. Our study highlights that AMPA and glyphosate origins in urban area are different. During dry period, detergent degradation seemed to be the major AMPA source in wastewater.

  12. Occurrence of glyphosate and AMPA residues in soy-based infant formula sold in Brazil.

    Science.gov (United States)

    Rodrigues, Nadia Regina; de Souza, Ana Paula Ferreira

    2018-04-01

    Glyphosate is an herbicide widely used in the world, being applied in several crops, among them soybeans. Recently, glyphosate and its metabolite aminomethylphosphonic acid (AMPA) have been identified as possible contributors to the emergence of various diseases such as autism, Parkinson's and Alzheimer's diseases, as well as cancer. The child population-consuming cereal-based foods is the most exposed to the effects of pesticides because of their developmental phase and they have a higher food intake per kilogram of body weight than adults. The presence of glyphosate and AMPA residues in soy-based infant formulas was evaluated during the years 2012-2017, totalising 105 analyses carried out on 10 commercial brands from different batches. Glyphosate and AMPA were determined by liquid chromatography with fluorescence detection after derivatisation reaction. The method was validated and showed accuracy and precision with a limit of quantification (LOQ) of 0.02 mg kg -1 . Among those samples that contained levels above the LOQ, the variation of glyphosate residues was from 0.03 mg kg -1 to 1.08 mg kg -1 and for AMPA residues was from 0.02 mg kg -1 to 0.17 mg kg -1 . This is the first scientific communication about glyphosate and AMPA contamination in soy-based infant formula in Brazil, The study was conducted under good laboratory practice (GLP) and supported by good scientific practice.

  13. Structure and assembly mechanism for heteromeric kainate receptors.

    Science.gov (United States)

    Kumar, Janesh; Schuck, Peter; Mayer, Mark L

    2011-07-28

    Native glutamate receptor ion channels are tetrameric assemblies containing two or more different subunits. NMDA receptors are obligate heteromers formed by coassembly of two or three divergent gene families. While some AMPA and kainate receptors can form functional homomeric ion channels, the KA1 and KA2 subunits are obligate heteromers which function only in combination with GluR5-7. The mechanisms controlling glutamate receptor assembly involve an initial step in which the amino terminal domains (ATD) assemble as dimers. Here, we establish by sedimentation velocity that the ATDs of GluR6 and KA2 coassemble as a heterodimer of K(d) 11 nM, 32,000-fold lower than the K(d) for homodimer formation by KA2; we solve crystal structures for the GluR6/KA2 ATD heterodimer and heterotetramer assemblies. Using these structures as a guide, we perform a mutant cycle analysis to probe the energetics of assembly and show that high-affinity ATD interactions are required for biosynthesis of functional heteromeric receptors. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. β-arrestins negatively control human adrenomedullin type 1-receptor internalization.

    Science.gov (United States)

    Kuwasako, Kenji; Kitamura, Kazuo; Nagata, Sayaka; Sekiguchi, Toshio; Danfeng, Jiang; Murakami, Manabu; Hattori, Yuichi; Kato, Johji

    2017-05-27

    Adrenomedullin (AM) is a potent hypotensive peptide that exerts a powerful variety of protective effects against multiorgan damage through the AM type 1 receptor (AM 1 receptor), which consists of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 2 (RAMP2). Two β-arrestin (β-arr) isoforms, β-arr-1 and β-arr-2, play a central role in the agonist-induced internalization of many receptors for receptor resensitization. Notably, β-arr-biased agonists are now being tested in phase II clinical trials, targeting acute pain and acute heart failure. Here, we examined the effects of β-arr-1 and β-arr-2 on human AM 1 receptor internalization. We constructed a V5-tagged chimera in which the cytoplasmic C-terminal tail (C-tail) of CLR was replaced with that of the β 2 -adrenergic receptor (β 2 -AR), and it was transiently transfected into HEK-293 cells that stably expressed RAMP2. The cell-surface expression and internalization of the wild-type or chimeric receptor were quantified by flow cytometric analysis. The [ 125 I]AM binding and the AM-induced cAMP production of these receptors were also determined. Surprisingly, the coexpression of β-arr-1 or -2 resulted in significant decreases in AM 1 receptor internalization without affecting AM binding and signaling prior to receptor internalization. Dominant-negative (DN) β-arr-1 or -2 also significantly decreased AM-induced AM 1 receptor internalization. In contrast, the AM-induced internalization of the chimeric AM 1 receptor was markedly augmented by the cotransfection of β-arr-1 or -2 and significantly reduced by the coexpression of DN-β-arr-1 or -2. These results were consistent with those seen for β 2 -AR. Thus, both β-arrs negatively control AM 1 receptor internalization, which depends on the C-tail of CLR. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Sources of aminomethylphosphonic acid (AMPA) in urban and rural catchments in Ontario, Canada: Glyphosate or phosphonates in wastewater?

    International Nuclear Information System (INIS)

    Struger, J.; Van Stempvoort, D.R.; Brown, S.J.

    2015-01-01

    Correlation analysis suggests that occurrences of AMPA in streams of southern Ontario are linked mainly to glyphosate in both urban and rural settings, rather than to wastewater sources, as some previous studies have suggested. For this analysis the artificial sweetener acesulfame was analyzed as a wastewater indicator in surface water samples collected from urban and rural settings in southern Ontario, Canada. This interpretation is supported by the concurrence of seasonal fluctuations of glyphosate and AMPA concentrations. Herbicide applications in larger urban centres and along major transportation corridors appear to be important sources of glyphosate and AMPA in surface water, in addition to uses of this herbicide in rural and mixed use areas. Fluctuations in concentrations of acesulfame and glyphosate residues were found to be related to hydrologic events. - Highlights: • Widespread occurrence of glyphosate and AMPA in surface waters of southern Ontario. • Linked to applications of glyphosate in urban and rural settings. • Supported by lack of correlation between AMPA and the wastewater tracer acesulfame. • Contrasts with view that AMPA found in the environment is derived from wastewater. • AMPA more persistent than glyphosate and both fluctuated with hydrological cycles. - The occurrence of AMPA in streams in southern Ontario is linked mainly to glyphosate rather than wastewater sources

  16. Synthesis and pharmacological characterization at glutamate receptors of the four enantiopure isomers of tricholomic acid

    DEFF Research Database (Denmark)

    Pinto, Andrea; Conti, Paola; De Amici, Marco

    2008-01-01

    of the studied amino acids reflect the relationship between the activity/selectivity and the stereochemistry of the two stereogenic centers: while the (2 S,5' S) stereoisomer is an agonist at the AMPA and KA receptors, its (2 R,5' R) enantiomer interacts selectively with the NMDA receptors; the (2 S,5' R...

  17. Parkinson's disease treatment may cause impulse-control disorder via dopamine D3 receptors.

    Science.gov (United States)

    Seeman, Philip

    2015-04-01

    In treating Parkinson's disease with dopaminergic agonists, such as pramipexole, ropinirole, pergolide, rotigotine, apomorphine, or bromocriptine, it has been observed that a significant number of patients develop impulse-control disorders, such as compulsive shopping, pathological gambling, or hypersexuality. Because the dopamine agonists have high affinities for the dopamine D2 and D3 receptors, the drug dissociation constants of these drugs at the functional high-affinity states of these receptors, namely D2High and D3High, were compared. The data show that, compared to the other dopamine agonist drugs, pramipexole has a relatively high selectivity for the dopamine D3 receptor, as compared to D2, suggesting that the D3 receptor may be a primary target for pramipexole. There is a trend showing that the proportion of impulse-control disorders is related to the selectivity for D3 receptors over D2 receptors, with pramipexole having the highest association with, or frequency of, impulse-control disorders. While the number of studies are limited, the proportion of patients with impulse-control disorder in Parkinson patients treated with an add-on agonist were 32% for pramipexole, 25% for ropinirole, 16% for pergolide, 22% for rotigotine, 10% for apomorphine, and 6.8% for bromocriptine. Clinically, temporary replacement of pramipexole by bromocriptine may provide relief or reversal of the impulsive behavior associated with selective D3 stimulation by either pramipexole or ropinirole, while maintaining D2 stimulation needed for the anti-Parkinson action. © 2015 Wiley Periodicals, Inc.

  18. Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

    Science.gov (United States)

    Kim, Sun-Gyun; Lee, Bora; Kim, Dae-Hwan; Kim, Juhee; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

    2013-10-01

    Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

  19. Perirhinal Cortex Muscarinic Receptor Blockade Impairs Taste Recognition Memory Formation

    Science.gov (United States)

    Gutierrez, Ranier; De la Cruz, Vanesa; Rodriguez-Ortiz, Carlos J.; Bermudez-Rattoni, Federico

    2004-01-01

    The relevance of perirhinal cortical cholinergic and glutamatergic neurotransmission for taste recognition memory and learned taste aversion was assessed by microinfusions of muscarinic (scopolamine), NMDA (AP-5), and AMPA (NBQX) receptor antagonists. Infusions of scopolamine, but not AP5 or NBQX, prevented the consolidation of taste recognition…

  20. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  1. Serotonin 6 receptor controls alzheimer?s disease and depression

    OpenAIRE

    Yun, Hyung-Mun; Park, Kyung-Ran; Kim, Eun-Cheol; Kim, Sanghyeon; Hong, Jin Tae

    2015-01-01

    Alzheimer?s disease (AD) and depression in late life are one of the most severe health problems in the world disorders. Serotonin 6 receptor (5-HT6R) has caused much interest for potential roles in AD and depression. However, a causative role of perturbed 5-HT6R function between two diseases was poorly defined. In the present study, we found that a 5-HT6R antagonist, SB271036 rescued memory impairment by attenuating the generation of A? via the inhibition of ?-secretase activity and the inact...

  2. Non-point source pollution of glyphosate and AMPA in a rural basin from the southeast Pampas, Argentina.

    Science.gov (United States)

    Okada, Elena; Pérez, Débora; De Gerónimo, Eduardo; Aparicio, Virginia; Massone, Héctor; Costa, José Luis

    2018-05-01

    We measured the occurrence and seasonal variations of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), in different environmental compartments within the limits of an agricultural basin. This topic is of high relevance since glyphosate is the most applied pesticide in agricultural systems worldwide. We were able to quantify the seasonal variations of glyphosate that result mainly from endo-drift inputs, that is, from direct spraying either onto genetically modified (GM) crops (i.e., soybean and maize) or onto weeds in no-till practices. We found that both glyphosate and AMPA accumulate in soil, but the metabolite accumulates to a greater extent due to its higher persistence. Knowing that glyphosate and AMPA were present in soils (> 93% of detection for both compounds), we aimed to study the dispersion to other environmental compartments (surface water, stream sediments, and groundwater), in order to establish the degree of non-point source pollution. Also, we assessed the relationship between the water-table depth and glyphosate and AMPA levels in groundwater. All of the studied compartments had variable levels of glyphosate and AMPA. The highest frequency of detections was found in the stream sediments samples (glyphosate 95%, AMPA 100%), followed by surface water (glyphosate 28%, AMPA 50%) and then groundwater (glyphosate 24%, AMPA 33%). Despite glyphosate being considered a molecule with low vertical mobility in soils, we found that its detection in groundwater was strongly associated with the month where glyphosate concentration in soil was the highest. However, we did not find a direct relation between groundwater table depth and glyphosate or AMPA detections. This is the first simultaneous study of glyphosate and AMPA seasonal variations in soil, groundwater, surface water, and sediments within a rural basin.

  3. Genetic inactivation of mGlu5 receptor improves motor coordination in the Grm1crv4 mouse model of SCAR13 ataxia.

    Science.gov (United States)

    Bossi, Simone; Musante, Ilaria; Bonfiglio, Tommaso; Bonifacino, Tiziana; Emionite, Laura; Cerminara, Maria; Cervetto, Chiara; Marcoli, Manuela; Bonanno, Giambattista; Ravazzolo, Roberto; Pittaluga, Anna; Puliti, Aldamaria

    2018-01-01

    Deleterious mutations in the glutamate receptor metabotropic 1 gene (GRM1) cause a recessive form of cerebellar ataxia, SCAR13. GRM1 and GRM5 code for the metabotropic glutamate type 1 (mGlu1) and type 5 (mGlu5) receptors, respectively. Their different expression profiles suggest they could have distinct functional roles. In a previous study, homozygous mice lacking mGlu1 receptors (Grm1 crv4/crv4 ) and exhibiting ataxia presented cerebellar overexpression of mGlu5 receptors, that was proposed to contribute to the mouse phenotype. To test this hypothesis, we here crossed Grm1 crv4 and Grm5 ko mice to generate double mutants (Grm1 crv4/crv4 Grm5 ko/ko ) lacking both mGlu1 and mGlu5 receptors. Double mutants and control mice were analyzed for spontaneous behavior and for motor activity by rotarod and footprint analyses. In the same mice, the release of glutamate from cerebellar nerve endings (synaptosomes) elicited by 12mM KCl or by α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) was also evaluated. Motor coordination resulted improved in double mutants when compared to Grm1 crv4/crv4 mice. Furthermore, in in vitro studies, glutamate release elicited by both KCl depolarization and activation of AMPA autoreceptors resulted reduced in Grm1 crv4/crv4 mice compared to wild type mice, while it presented normal levels in double mutants. Moreover, we found that Grm1 crv4/crv4 mice showed reduced expression of GluA2/3 AMPA receptor subunits in cerebellar synaptosomes, while it resulted restored to wild type level in double mutants. To conclude, blocking of mGlu5 receptor reduced the dysregulation of glutamate transmission and improved motor coordination in the Grm1 crv4 mouse model of SCAR13, thus suggesting the possible usefulness of pharmacological therapies based on modulation of mGlu5 receptor activity for the treatment of this type of ataxia. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Diverse FGF receptor signaling controls astrocyte specification and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyungjun [School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); Song, Mi-Ryoung, E-mail: msong@gist.ac.kr [School of Life Sciences, Gwangju Institute of Science and Technology, Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); Bioimaging Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2010-05-07

    During CNS development, pluripotency neuronal progenitor cells give rise in succession to neurons and glia. Fibroblast growth factor-2 (FGF-2), a major signal that maintains neural progenitors in the undifferentiated state, is also thought to influence the transition from neurogenesis to gliogenesis. Here we present evidence that FGF receptors and underlying signaling pathways transmit the FGF-2 signals that regulate astrocyte specification aside from its mitogenic activity. Application of FGF-2 to cortical progenitors suppressed neurogenesis whereas treatment with an FGFR antagonist in vitro promoted neurogenesis. Introduction of chimeric FGFRs with mutated tyrosine residues into cortical progenitors and drug treatments to specifically block individual downstream signaling pathways revealed that the overall activity of FGFR rather than individual autophosphorylation sites is important for delivering signals for glial specification. In contrast, a signal for cell proliferation by FGFR was mainly delivered by MAPK pathway. Together our findings indicate that FGFR activity promotes astrocyte specification in the developing CNS.

  5. Diverse FGF receptor signaling controls astrocyte specification and proliferation

    International Nuclear Information System (INIS)

    Kang, Kyungjun; Song, Mi-Ryoung

    2010-01-01

    During CNS development, pluripotency neuronal progenitor cells give rise in succession to neurons and glia. Fibroblast growth factor-2 (FGF-2), a major signal that maintains neural progenitors in the undifferentiated state, is also thought to influence the transition from neurogenesis to gliogenesis. Here we present evidence that FGF receptors and underlying signaling pathways transmit the FGF-2 signals that regulate astrocyte specification aside from its mitogenic activity. Application of FGF-2 to cortical progenitors suppressed neurogenesis whereas treatment with an FGFR antagonist in vitro promoted neurogenesis. Introduction of chimeric FGFRs with mutated tyrosine residues into cortical progenitors and drug treatments to specifically block individual downstream signaling pathways revealed that the overall activity of FGFR rather than individual autophosphorylation sites is important for delivering signals for glial specification. In contrast, a signal for cell proliferation by FGFR was mainly delivered by MAPK pathway. Together our findings indicate that FGFR activity promotes astrocyte specification in the developing CNS.

  6. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  7. Nuclear hormone receptor NHR-49 controls fat consumption and fatty acid composition in C. elegans.

    Directory of Open Access Journals (Sweden)

    Marc R Van Gilst

    2005-02-01

    Full Text Available Mammalian nuclear hormone receptors (NHRs, such as liver X receptor, farnesoid X receptor, and peroxisome proliferator-activated receptors (PPARs, precisely control energy metabolism. Consequently, these receptors are important targets for the treatment of metabolic diseases, including diabetes and obesity. A thorough understanding of NHR fat regulatory networks has been limited, however, by a lack of genetically tractable experimental systems. Here we show that deletion of the Caenorhabditis elegans NHR gene nhr-49 yielded worms with elevated fat content and shortened life span. Employing a quantitative RT-PCR screen, we found that nhr-49 influenced the expression of 13 genes involved in energy metabolism. Indeed, nhr-49 served as a key regulator of fat usage, modulating pathways that control the consumption of fat and maintain a normal balance of fatty acid saturation. We found that the two phenotypes of the nhr-49 knockout were linked to distinct pathways and were separable: The high-fat phenotype was due to reduced expression of enzymes in fatty acid beta-oxidation, and the shortened adult life span resulted from impaired expression of a stearoyl-CoA desaturase. Despite its sequence relationship with the mammalian hepatocyte nuclear factor 4 receptor, the biological activities of nhr-49 were most similar to those of the mammalian PPARs, implying an evolutionarily conserved role for NHRs in modulating fat consumption and composition. Our findings in C. elegans provide novel insights into how NHR regulatory networks are coordinated to govern fat metabolism.

  8. Nuclear hormone receptor NHR-49 controls fat consumption and fatty acid composition in C. elegans.

    Science.gov (United States)

    Van Gilst, Marc R; Hadjivassiliou, Haralambos; Jolly, Amber; Yamamoto, Keith R

    2005-02-01

    Mammalian nuclear hormone receptors (NHRs), such as liver X receptor, farnesoid X receptor, and peroxisome proliferator-activated receptors (PPARs), precisely control energy metabolism. Consequently, these receptors are important targets for the treatment of metabolic diseases, including diabetes and obesity. A thorough understanding of NHR fat regulatory networks has been limited, however, by a lack of genetically tractable experimental systems. Here we show that deletion of the Caenorhabditis elegans NHR gene nhr-49 yielded worms with elevated fat content and shortened life span. Employing a quantitative RT-PCR screen, we found that nhr-49 influenced the expression of 13 genes involved in energy metabolism. Indeed, nhr-49 served as a key regulator of fat usage, modulating pathways that control the consumption of fat and maintain a normal balance of fatty acid saturation. We found that the two phenotypes of the nhr-49 knockout were linked to distinct pathways and were separable: The high-fat phenotype was due to reduced expression of enzymes in fatty acid beta-oxidation, and the shortened adult life span resulted from impaired expression of a stearoyl-CoA desaturase. Despite its sequence relationship with the mammalian hepatocyte nuclear factor 4 receptor, the biological activities of nhr-49 were most similar to those of the mammalian PPARs, implying an evolutionarily conserved role for NHRs in modulating fat consumption and composition. Our findings in C. elegans provide novel insights into how NHR regulatory networks are coordinated to govern fat metabolism.

  9. Glyphosate and AMPA distribution in wind-eroded sediment derived from loess soil

    NARCIS (Netherlands)

    Martins Bento, Celia; Goossens, Dirk; Rezaei, Mahrooz; Riksen, M.J.P.M.; Mol, J.G.J.; Ritsema, C.J.; Geissen, V.

    2017-01-01

    Glyphosate is one of the most used herbicides in agricultural lands worldwide. Wind-eroded sediment and dust, as an environmental transport pathway of glyphosate and of its main metabolite aminomethylphosphonic acid (AMPA), can result in environmental- and human exposure far beyond the agricultural

  10. Lactobacillus bulgaricus Sebagai Probiotik Guna Peningkatan Kualitas Ampas Tahu Untuk Pakan Cacing Tanah

    OpenAIRE

    Purkan, Purkan

    2017-01-01

    AbstrakPenelitian ini bertujuan untuk menentukan aktivitas protease dari probiotik Lactobacillus bulgaricus dan pengaruh probiotik Lactobacillus bulgaricus dalam fermentasi pakan ampas tahu untuk meningkatkan produktivitas cacing tanah. Metode yang digunakan untuk penentuan aktivitas protease dalam hidrolisis substrat kasein adalah metode Bradford. Dari hasil penelitian, probiotik Lactobacillus bulgaricus mengeluarkan protease selama 18 jam pertumbuhan, dengan aktivitas protease sebesar 131,0...

  11. Memory control by the B cell antigen receptor.

    Science.gov (United States)

    Engels, Niklas; Wienands, Jürgen

    2018-05-01

    The generation of memory B cells (MBCs) that have undergone immunoglobulin class switching from IgM, which dominates primary antibody responses, to other immunoglobulin isoforms is a hallmark of immune memory. Hence, humoral immunological memory is characterized by the presence of serum immunoglobulins of IgG subtypes known as the γ-globulin fraction of blood plasma proteins. These antibodies reflect the antigen experience of B lymphocytes and their repeated triggering. In fact, efficient protection against a previously encountered pathogen is critically linked to the production of pathogen-specific IgG molecules even in those cases where the primary immune response required cellular immunity, for example, T cell-mediated clearance of intracellular pathogens such as viruses. Besides IgG, also IgA and IgE can provide humoral immunity depending on the microbe's nature and infection route. The molecular mechanisms underlying the preponderance of switched immunoglobulin isotypes during memory antibody responses are a matter of active and controversial debate. Here, we summarize the phenotypic characteristics of distinct MBC subpopulations and discuss the decisive roles of different B cell antigen receptor isotypes for the functional traits of class-switched B cell populations. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. The inositol trisphosphate receptor in the control of autophagy.

    Science.gov (United States)

    Criollo, Alfredo; Vicencio, José Miguel; Tasdemir, Ezgi; Maiuri, M Chiara; Lavandero, Sergio; Kroemer, Guido

    2007-01-01

    The second messenger myo-inositol-1,4,5-trisphosphate (IP(3)) acts on the IP(3) receptor (IP(3)R), an IP(3)-activated Ca(2+) channel of the endoplasmic reticulum (ER). The IP(3)R agonist IP(3) inhibits starvation-induced autophagy. The IP(3)R antagonist xestospongin B induces autophagy in human cells through a pathway that requires the obligate contribution of Beclin-1, Atg5, Atg10, Atg12 and hVps34, yet is inhibited by ER-targeted Bcl-2 or Bcl-XL, two proteins that physically interact with IP(3)R. Autophagy can also be induced by depletion of the IP(3)R by small interfering RNAs. Autophagy induction by IP(3)R blockade cannot be explained by changes in steady state levels of Ca(2+) in the endoplasmic reticulum (ER) and the cytosol. Autophagy induction by IP(3)R blockade is effective in cells lacking the obligate mediator of ER stress IRE1. In contrast, IRE1 is required for autophagy induced by ER stress-inducing agents such a tunicamycin or thapsigargin. These findings suggest that there are several distinct pathways through which autophagy can be initiated at the level of the ER.

  13. Muscarinic receptors in amygdala control trace fear conditioning.

    Directory of Open Access Journals (Sweden)

    Amber N Baysinger

    Full Text Available Intelligent behavior requires transient memory, which entails the ability to retain information over short time periods. A newly-emerging hypothesis posits that endogenous persistent firing (EPF is the neurophysiological foundation for aspects or types of transient memory. EPF is enabled by the activation of muscarinic acetylcholine receptors (mAChRs and is triggered by suprathreshold stimulation. EPF occurs in several brain regions, including the lateral amygdala (LA. The present study examined the role of amygdalar mAChRs in trace fear conditioning, a paradigm that requires transient memory. If mAChR-dependent EPF selectively supports transient memory, then blocking amygdalar mAChRs should impair trace conditioning, while sparing delay and context conditioning, which presumably do not rely upon transient memory. To test the EPF hypothesis, LA was bilaterally infused, prior to trace or delay conditioning, with either a mAChR antagonist (scopolamine or saline. Computerized video analysis quantified the amount of freezing elicited by the cue and by the training context. Scopolamine infusion profoundly reduced freezing in the trace conditioning group but had no significant effect on delay or context conditioning. This pattern of results was uniquely anticipated by the EPF hypothesis. The present findings are discussed in terms of a systems-level theory of how EPF in LA and several other brain regions might help support trace fear conditioning.

  14. Muscarinic receptors in amygdala control trace fear conditioning.

    Science.gov (United States)

    Baysinger, Amber N; Kent, Brianne A; Brown, Thomas H

    2012-01-01

    Intelligent behavior requires transient memory, which entails the ability to retain information over short time periods. A newly-emerging hypothesis posits that endogenous persistent firing (EPF) is the neurophysiological foundation for aspects or types of transient memory. EPF is enabled by the activation of muscarinic acetylcholine receptors (mAChRs) and is triggered by suprathreshold stimulation. EPF occurs in several brain regions, including the lateral amygdala (LA). The present study examined the role of amygdalar mAChRs in trace fear conditioning, a paradigm that requires transient memory. If mAChR-dependent EPF selectively supports transient memory, then blocking amygdalar mAChRs should impair trace conditioning, while sparing delay and context conditioning, which presumably do not rely upon transient memory. To test the EPF hypothesis, LA was bilaterally infused, prior to trace or delay conditioning, with either a mAChR antagonist (scopolamine) or saline. Computerized video analysis quantified the amount of freezing elicited by the cue and by the training context. Scopolamine infusion profoundly reduced freezing in the trace conditioning group but had no significant effect on delay or context conditioning. This pattern of results was uniquely anticipated by the EPF hypothesis. The present findings are discussed in terms of a systems-level theory of how EPF in LA and several other brain regions might help support trace fear conditioning.

  15. Serotonin 6 receptor controls Alzheimer's disease and depression.

    Science.gov (United States)

    Yun, Hyung-Mun; Park, Kyung-Ran; Kim, Eun-Cheol; Kim, Sanghyeon; Hong, Jin Tae

    2015-09-29

    Alzheimer's disease (AD) and depression in late life are one of the most severe health problems in the world disorders. Serotonin 6 receptor (5-HT6R) has caused much interest for potential roles in AD and depression. However, a causative role of perturbed 5-HT6R function between two diseases was poorly defined. In the present study, we found that a 5-HT6R antagonist, SB271036 rescued memory impairment by attenuating the generation of Aβ via the inhibition of γ-secretase activity and the inactivation of astrocytes and microglia in the AD mouse model. It was found that the reduction of serotonin level was significantly recovered by SB271036, which was mediated by an indirect regulation of serotonergic neurons via GABA. Selective serotonin reuptake inhibitor (SSRI), fluoxetine significantly improved cognitive impairment and behavioral changes. In human brain of depression patients, we then identified the potential genes, amyloid beta (A4) precursor protein-binding, family A, member 2 (APBA2), well known AD modulators by integrating datasets from neuropathology, microarray, and RNA seq. studies with correlation analysis tools. And also, it was demonstrated in mouse models and patients of AD. These data indicate functional network of 5-HT6R between AD and depression.

  16. Modeling Canadian Quality Control Test Program for Steroid Hormone Receptors in Breast Cancer: Diagnostic Accuracy Study.

    Science.gov (United States)

    Pérez, Teresa; Makrestsov, Nikita; Garatt, John; Torlakovic, Emina; Gilks, C Blake; Mallett, Susan

    The Canadian Immunohistochemistry Quality Control program monitors clinical laboratory performance for estrogen receptor and progesterone receptor tests used in breast cancer treatment management in Canada. Current methods assess sensitivity and specificity at each time point, compared with a reference standard. We investigate alternative performance analysis methods to enhance the quality assessment. We used 3 methods of analysis: meta-analysis of sensitivity and specificity of each laboratory across all time points; sensitivity and specificity at each time point for each laboratory; and fitting models for repeated measurements to examine differences between laboratories adjusted by test and time point. Results show 88 laboratories participated in quality control at up to 13 time points using typically 37 to 54 histology samples. In meta-analysis across all time points no laboratories have sensitivity or specificity below 80%. Current methods, presenting sensitivity and specificity separately for each run, result in wide 95% confidence intervals, typically spanning 15% to 30%. Models of a single diagnostic outcome demonstrated that 82% to 100% of laboratories had no difference to reference standard for estrogen receptor and 75% to 100% for progesterone receptor, with the exception of 1 progesterone receptor run. Laboratories with significant differences to reference standard identified with Generalized Estimating Equation modeling also have reduced performance by meta-analysis across all time points. The Canadian Immunohistochemistry Quality Control program has a good design, and with this modeling approach has sufficient precision to measure performance at each time point and allow laboratories with a significantly lower performance to be targeted for advice.

  17. Pharmacological properties of homomeric and heteromeric GluR1o and GluR3o receptors

    DEFF Research Database (Denmark)

    Nielsen, B S; Banke, T G; Schousboe, A

    1998-01-01

    Homomeric and heteromeric alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor subunits GluR1o and GluR3o were expressed in Spodoptera frugiperda (Sf9) insect cells. Membranes containing the recombinant receptors showed a doublet of bands of the expected size (99-109 kDa) after...

  18. Control of transcriptional repression of the vitellogenin receptor gene in largemouth bass (Micropterus salmoides) by select estrogen receptors isotypes.

    Science.gov (United States)

    Dominguez, Gustavo A; Bisesi, Joseph H; Kroll, Kevin J; Denslow, Nancy D; Sabo-Attwood, Tara

    2014-10-01

    The vitellogenin receptor (Vtgr) plays an important role in fish reproduction. This receptor functions to incorporate vitellogenin (Vtg), a macromolecule synthesized and released from the liver in the bloodstream, into oocytes where it is processed into yolk. Although studies have focused on the functional role of Vtgr in fish, the mechanistic control of this gene is still unexplored. Here we report the identification and analysis of the first piscine 5' regulatory region of the vtgr gene which was cloned from largemouth bass (Micropterus salmoides). Using this putative promoter sequence, we investigated a role for hormones, including insulin and 17β-estradiol (E2), in transcriptional regulation through cell-based reporter assays. No effect of insulin was observed, however, E2 was able to repress transcriptional activity of the vtgr promoter through select estrogen receptor subtypes, Esr1 and Esr2a but not Esr2b. Electrophoretic mobility shift assay demonstrated that Esr1 likely interacts with the vtgr promoter region through half ERE and/or SP1 sites, in part. Finally we also show that ethinylestradiol (EE2), but not bisphenol-A (BPA), represses promoter activity similarly to E2. These results reveal for the first time that the Esr1 isoform may play an inhibitory role in the expression of LMB vtgr mRNA under the influence of E2, and potent estrogens such as EE2. In addition, this new evidence suggests that vtgr may be a target of select endocrine disrupting compounds through environmental exposures. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  19. Transcription control and neuronal differentiation by agents that activate the LXR nuclear receptor family.

    Science.gov (United States)

    Schmidt, A; Vogel, R; Holloway, M K; Rutledge, S J; Friedman, O; Yang, Z; Rodan, G A; Friedman, E

    1999-09-10

    LXR and PPAR receptors belong to the nuclear receptor superfamily of transcriptional activating factors. Using ligand-dependent transcription assays, we found that 5-tetradecyloxy-2-furancarboxylic acid (TOFA) transactivates chimeric receptors composed of the glucocorticoid receptor DNA binding domain and the ligand binding regions of PPARalpha, PPARbeta (NUC-1) and LXRbeta (NER) receptors. In the same assays, ligands for PPARs (oleic acid, WY-14643 and L-631,033) and LXRs (hydroxycholesterols) maintain their respective receptor selectivity. TOFA and hydroxycholesterols also stimulate transcription from a minimal fibrinogen promoter that is under the control of AP-1 or NF-kappaB transcription factor binding sites. In addition to their effects on transcription, these LXRbeta activators induce neuronal differentiation in rat pheochromocytoma cells. TOFA and the natural LXR agonist, 22 (R)-hydroxycholesterol, stimulate neurite outgrowth in 55 and 28% of cells, respectively. No neurite outgrowth was induced by the related 22(S)-hydroxycholesterol, which does not activate the LXR family. These results suggest that the hydroxycholesterol signaling pathway has a complex effect on transcription that mediates the activity of TOFA and hydroxycholesterol on neuronal differentiation in pheochromocytoma cells.

  20. How membrane lipids control the 3D structure and function of receptors

    Directory of Open Access Journals (Sweden)

    Jacques Fantini

    2018-02-01

    Full Text Available The cohabitation of lipids and proteins in the plasma membrane of mammalian cells is controlled by specific biochemical and biophysical rules. Lipids may be either constitutively tightly bound to cell-surface receptors (non-annular lipids or less tightly attached to the external surface of the protein (annular lipids. The latter are exchangeable with surrounding bulk membrane lipids on a faster time scale than that of non-annular lipids. Not only do non-annular lipids bind to membrane proteins through stereoselective mechanisms, they can also help membrane receptors acquire (or maintain a functional 3D structure. Cholesterol is the prototype of membrane lipids that finely controls the 3D structure and function of receptors. However, several other lipids such as sphingolipids may also modulate the function of membrane proteins though conformational adjustments. All these concepts are discussed in this review in the light of representative examples taken from the literature.

  1. Serotonin receptor 3A controls interneuron migration into the neocortex

    NARCIS (Netherlands)

    Murthy, S.; Niquille, M.; Hurni, N.; Limoni, G.; Frazer, S.; Chameau, P.; van Hooft, J.A.; Vitalis, T.; Dayer, A.

    2014-01-01

    Neuronal excitability has been shown to control the migration and cortical integration of reelin-expressing cortical interneurons (INs) arising from the caudal ganglionic eminence (CGE), supporting the possibility that neurotransmitters could regulate this process. Here we show that the ionotropic

  2. A single amino acid residue controls Ca2+ signaling by an octopamine receptor from Drosophila melanogaster.

    Science.gov (United States)

    Hoff, Max; Balfanz, Sabine; Ehling, Petra; Gensch, Thomas; Baumann, Arnd

    2011-07-01

    Rhythmic activity of cells and cellular networks plays an important role in physiology. In the nervous system oscillations of electrical activity and/or second messenger concentrations are important to synchronize neuronal activity. At the molecular level, rhythmic activity can be initiated by different routes. We have recently shown that an octopamine-activated G-protein-coupled receptor (GPCR; DmOctα1Rb, CG3856) from Drosophila initiates Ca(2+) oscillations. Here, we have unraveled the molecular basis of cellular Ca(2+) signaling controlled by the DmOctα1Rb receptor using a combination of pharmacological intervention, site-directed mutagenesis, and functional cellular Ca(2+) imaging on heterologously expressed receptors. Phosphorylation of a single amino acid residue in the third intracellular loop of the GPCR by PKC is necessary and sufficient to desensitize the receptor. From its desensitized state, DmOctα1Rb is resensitized by dephosphorylation, and a new Ca(2+) signal occurs on octopamine stimulation. Our findings show that transient changes of the receptor's surface profile have a strong effect on its physiological signaling properties. We expect that the detailed knowledge of DmOctα1Rb-dependent signal transduction fosters the identification of specific drugs that can be used for GPCR-mediated pest control, since octopamine serves important physiological and behavioral functions in arthropods.

  3. Remote control of therapeutic T cells through a small molecule-gated chimeric receptor.

    Science.gov (United States)

    Wu, Chia-Yung; Roybal, Kole T; Puchner, Elias M; Onuffer, James; Lim, Wendell A

    2015-10-16

    There is growing interest in using engineered cells as therapeutic agents. For example, synthetic chimeric antigen receptors (CARs) can redirect T cells to recognize and eliminate tumor cells expressing specific antigens. Despite promising clinical results, these engineered T cells can exhibit excessive activity that is difficult to control and can cause severe toxicity. We designed "ON-switch" CARs that enable small-molecule control over T cell therapeutic functions while still retaining antigen specificity. In these split receptors, antigen-binding and intracellular signaling components assemble only in the presence of a heterodimerizing small molecule. This titratable pharmacologic regulation could allow physicians to precisely control the timing, location, and dosage of T cell activity, thereby mitigating toxicity. This work illustrates the potential of combining cellular engineering with orthogonal chemical tools to yield safer therapeutic cells that tightly integrate cell-autonomous recognition and user control. Copyright © 2015, American Association for the Advancement of Science.

  4. Remote control of therapeutic T cells through a small molecule-gated chimeric receptor

    Science.gov (United States)

    Wu, Chia-Yung; Roybal, Kole T.; Puchner, Elias M.; Onuffer, James; Lim, Wendell A.

    2016-01-01

    There is growing promise in using engineered cells as therapeutic agents. For example, synthetic Chimeric Antigen Receptors (CARs) can redirect T cells to recognize and eliminate tumor cells expressing specific antigens. Despite promising clinical results, excessive activity and poor control over such engineered T cells can cause severe toxicities. We present the design of “ON-switch” CARs that enable small molecule-control over T cell therapeutic functions, while still retaining antigen specificity. In these split receptors, antigen binding and intracellular signaling components only assemble in the presence of a heterodimerizing small molecule. This titratable pharmacologic regulation could allow physicians to precisely control the timing, location, and dosage of T cell activity, thereby mitigating toxicity. This work illustrates the potential of combining cellular engineering with orthogonal chemical tools to yield safer therapeutic cells that tightly integrate both cell autonomous recognition and user control. PMID:26405231

  5. Glufosinate ammonium induces convulsion through N-methyl-D-aspartate receptors in mice.

    Science.gov (United States)

    Matsumura, N; Takeuchi, C; Hishikawa, K; Fujii, T; Nakaki, T

    2001-05-18

    Glufosinate ammonium, a broad-spectrum herbicide, causes convulsion in rodents and humans. Because of the structural similarities between glufosinate and glutamate, the convulsion induced by glufosinate ammonium may be ascribed to glutamate receptor activation. Three N-methyl-D-asparate (NMDA) receptor antagonists, dizocilpine, LY235959, and Compound 40, and an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist, NBQX, were coadministrated with glufosinate ammonium (80 mg/kg, intraperitoneally) in mice. Statistical analyses showed that the NMDA receptor antagonists markedly inhibited the convulsions, while the AMPA/kainate receptor antagonist had no effect on the convulsion. These results suggest that the convulsion caused by glufosinate ammonium is mediated through NMDA receptors.

  6. Atypical Opioid Mechanisms of Control of Injury-Induced Cutaneous Pain by Delta Receptors

    Science.gov (United States)

    2017-07-01

    i.e. mu opioid receptor agonists such as morphine) cause unacceptable side effects including addiction . Injuries suffered most frequently by active...slides. The slides were then processed for fluorescent in situ hybridization with RNAscope technology (ACD Biosystems) to detect Oprd1 mRNA, as...tissue as done in Bardoni et al., Neuron, 2014) and negative controls (no probe). Controls indicated that the technology and reagents work as expected

  7. Interactions of neurotoxins with non-NMDA glutamate receptors: an autoradiographic study

    International Nuclear Information System (INIS)

    Kuenig, G.; Niedermeyer, B.; Krause, F.; Hartmann, J.; Deckert, J.; Heinsen, H.; Beckmann, H.; Riederer, P.; Ransmayr, G.

    1994-01-01

    Neurotoxic substances are discussed to cause neurode-generation by acting as excitotoxins on glutamate receptors. We investigated the properties of L-beta-oxalyl-amino-alanine (L-BOAA) and 3,4,6-trihydroxyphenlyalanine (6-OH-Dopa) at the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) glutamate receptor and that of L-BOAA and domoic acid at the kainate glutamate receptor in human hippocampus. (3 H)AMPA binding in hippocampal subfields was inhibited by L-BOAA and 6-OH-Dopa with mean IC50-values in the low micromolar range. (3H)Kainate binding was inhibited by L-BOAA with similar potency as (3H)AMPA binding and by domoic acid with mean IC50-values in the low nanomolar range. These results support the notion that symptoms like anterograde amnesia and epileptic seizures seen in domoic acid intoxication and limbic symptoms, e.g. cognitive and mood impairment observed in neurolathyrism may be caused by excitotoxic action on non-NMDA receptors. The potent interaction of 6-OH-Dopa with the AMPA-receptor may point to a possible dopaminergic-glutamatergic interaction in the development of neurodegenerative diseases like Parkinson's and Huntington's disease. (author)

  8. Electroacupuncture Potentiates Cannabinoid Receptor-Mediated Descending Inhibitory Control in a Mouse Model of Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Yuan

    2018-04-01

    Full Text Available Knee osteoarthritis (KOA is a highly prevalent, chronic joint disorder, which can lead to chronic pain. Although electroacupuncture (EA is effective in relieving chronic pain in the clinic, the involved mechanisms remain unclear. Reduced diffuse noxius inhibitory controls (DNIC function is associated with chronic pain and may be related to the action of endocannabinoids. In the present study, we determined whether EA may potentiate cannabinoid receptor-mediated descending inhibitory control and inhibit chronic pain in a mouse model of KOA. We found that the optimized parameters of EA inhibiting chronic pain were the low frequency and high intensity (2 Hz + 1 mA. EA reversed the reduced expression of CB1 receptors and the 2-arachidonoylglycerol (2-AG level in the midbrain in chronic pain. Microinjection of the CB1 receptor antagonist AM251 into the ventrolateral periaqueductal gray (vlPAG can reversed the EA effect on pain hypersensitivity and DNIC function. In addition, CB1 receptors on GABAergic but not glutamatergic neurons are involved in the EA effect on DNIC function and descending inhibitory control of 5-HT in the medulla, thus inhibiting chronic pain. Our data suggest that endocannabinoid (2-AG-CB1R-GABA-5-HT may be a novel signaling pathway involved in the effect of EA improving DNIC function and inhibiting chronic pain.

  9. Neuropeptide Y2 receptors in anteroventral BNST control remote fear memory depending on extinction training.

    Science.gov (United States)

    Verma, Dilip; Tasan, Ramon; Sperk, Guenther; Pape, Hans-Christian

    2018-03-01

    The anterior bed nucleus of stria terminalis (BNST) is involved in reinstatement of extinguished fear, and neuropeptide Y2 receptors influence local synaptic signaling. Therefore, we hypothesized that Y2 receptors in anteroventral BNST (BNSTav) interfere with remote fear memory and that previous fear extinction is an important variable. C57BL/6NCrl mice were fear-conditioned, and a Y2 receptor-specific agonist (NPY 3-36 ) or antagonist (JNJ-5207787) was applied in BNSTav before fear retrieval at the following day. Remote fear memory was tested on day 16 in two groups of mice, which had (experiment 1) or had not (experiment 2) undergone extinction training after conditioning. In the group with extinction training, tests of remote fear memory revealed partial retrieval of extinction, which was prevented after blockade of Y2 receptors in BNSTav. No such effect was observed in the group with no extinction training, but stimulation of Y2 receptors in BNSTav mimicked the influence of extinction during tests of remote fear memory. Pharmacological manipulation of Y2 receptors in BNSTav before fear acquisition (experiment 3) had no effect on fear memory retrieval, extinction or remote fear memory. Furthermore, partial retrieval of extinction during tests of remote fear memory was associated with changes in number of c-Fos expressing neurons in BNSTav, which was prevented or mimicked upon Y2 blockade or stimulation in BNSTav. These results indicate that Y2 receptor manipulation in BNSTav interferes with fear memory and extinction retrieval at remote stages, likely through controlling neuronal activity in BNSTav during extinction training. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. GABAA receptor subunit gene expression in human prefrontal cortex: comparison of schizophrenics and controls

    Science.gov (United States)

    Akbarian, S.; Huntsman, M. M.; Kim, J. J.; Tafazzoli, A.; Potkin, S. G.; Bunney, W. E. Jr; Jones, E. G.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    The prefrontal cortex of schizophrenics is hypoactive and displays changes related to inhibitory, GABAergic neurons, and GABAergic synapses. These changes include decreased levels of glutamic acid decarboxylase (GAD), the enzyme for GABA synthesis, upregulation of muscimol binding, and downregulation of benzodiazepine binding to GABAA receptors. Studies in the visual cortex of nonhuman primates have demonstrated that gene expression for GAD and for several GABAA receptor subunit polypeptides is under control of neuronal activity, raising the possibility that similar mechanisms in the hypoactive prefrontal cortex of schizophrenics may explain the abnormalities in GAD and in GABAA receptor regulation. In the present study, which is the first of its type on human cerebral cortex, levels of mRNAs for six GABAA receptor subunits (alpha 1, alpha 2, alpha 5, beta 1, beta 2, gamma 2) and their laminar expression patterns were analyzed in the prefrontal cortex of schizophrenics and matched controls, using in situ hybridization histochemistry and densitometry. Three types of laminar expression pattern were observed: mRNAs for the alpha 1, beta 2, and gamma 2 subunits, which are the predominant receptor subunits expressed in the mature cortex, were expressed at comparatively high levels by cells of all six cortical layers, but most intensely by cells in lower layer III and layer IV. mRNAs for the alpha 2, alpha 5, and beta 1 subunits were expressed at lower levels; alpha 2 and beta 1 were expressed predominantly by cells in layers II, III, and IV; alpha 5 was expressed predominantly in layers IV, V, and VI. There were no significant changes in overall mRNA levels for any of the receptor subunits in the prefrontal cortex of schizophrenics, and the laminar expression pattern of all six receptor subunit mRNAs did not differ between schizophrenics and controls. Because gene expression for GABAA receptor subunits is not consistently altered in the prefrontal cortex of

  11. Gene Expression of Leptin and Long Leptin Receptor Isoform in Endometriosis: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Andrea Prestes Nácul

    2013-01-01

    Full Text Available In this study, leptin/BMI ratio in serum and peritoneal fluid and gene expression of leptin and long form leptin receptor (OB-RL were assessed in eutopic and ectopic endometria of women with endometriosis and controls. Increased serum leptin/BMI ratio was found in endometriosis patients. Leptin and OB-RL gene expression was significantly higher in ectopic versus eutopic endometrium of patients and controls. A positive, significant correlation was observed between leptin and OB-RL transcripts in ectopic endometria and also in eutopic endometria in endometriosis and control groups. A negative and significant correlation was found between OB-RL mRNA expression and peritoneal fluid leptin/BMI ratio only in endometriosis. These data suggest that, through a modulatory interaction with its active receptor, leptin might play a role in the development of endometrial implants.

  12. Kidney branching morphogenesis under the control of a ligand–receptor-based Turing mechanism

    International Nuclear Information System (INIS)

    Menshykau, Denis; Iber, Dagmar

    2013-01-01

    The main signalling proteins that control early kidney branching have been defined. Yet the underlying mechanism is still elusive. We have previously shown that a Schnakenberg-type Turing mechanism can recapitulate the branching and protein expression patterns in wild-type and mutant lungs, but it is unclear whether this mechanism would extend to other branched organs that are regulated by other proteins. Here, we show that the glial cell line-derived neurotrophic factor–RET regulatory interaction gives rise to a Schnakenberg-type Turing model that reproduces the observed budding of the ureteric bud from the Wolffian duct, its invasion into the mesenchyme and the observed branching pattern. The model also recapitulates all relevant protein expression patterns in wild-type and mutant mice. The lung and kidney models are both based on a particular receptor–ligand interaction and require (1) cooperative binding of ligand and receptor, (2) a lower diffusion coefficient for the receptor than for the ligand and (3) an increase in the receptor concentration in response to receptor–ligand binding (by enhanced transcription, more recycling or similar). These conditions are met also by other receptor–ligand systems. We propose that ligand–receptor-based Turing patterns represent a general mechanism to control branching morphogenesis and other developmental processes. (paper)

  13. Nutrient-sensing nuclear receptors PPARα and FXR control liver energy balance.

    Science.gov (United States)

    Preidis, Geoffrey A; Kim, Kang Ho; Moore, David D

    2017-04-03

    The nuclear receptors PPARα (encoded by NR1C1) and farnesoid X receptor (FXR, encoded by NR1H4) are activated in the liver in the fasted and fed state, respectively. PPARα activation induces fatty acid oxidation, while FXR controls bile acid homeostasis, but both nuclear receptors also regulate numerous other metabolic pathways relevant to liver energy balance. Here we review evidence that they function coordinately to control key nutrient pathways, including fatty acid oxidation and gluconeogenesis in the fasted state and lipogenesis and glycolysis in the fed state. We have also recently reported that these receptors have mutually antagonistic impacts on autophagy, which is induced by PPARα but suppressed by FXR. Secretion of multiple blood proteins is a major drain on liver energy and nutrient resources, and we present preliminary evidence that the liver secretome may be directly suppressed by PPARα, but induced by FXR. Finally, previous studies demonstrated a striking deficiency in bile acid levels in malnourished mice that is consistent with results in malnourished children. We present evidence that hepatic targets of PPARα and FXR are dysregulated in chronic undernutrition. We conclude that PPARα and FXR function coordinately to integrate liver energy balance.

  14. Changes in glutamate receptor subunits within the medulla in goats after section of the carotid sinus nerves

    Science.gov (United States)

    Miller, Justin Robert; Neumueller, Suzanne; Muere, Clarissa; Olesiak, Samantha; Pan, Lawrence; Bukowy, John D.; Daghistany, Asem O.; Hodges, Matthew R.

    2014-01-01

    The mechanisms which contribute to the time-dependent recovery of resting ventilation and the ventilatory CO2 chemoreflex after carotid body denervation (CBD) are poorly understood. Herein we tested the hypothesis that there are time-dependent changes in the expression of specific AMPA, NMDA, and/or neurokinin-1 (NK1R) receptors within respiratory-related brain stem nuclei acutely or chronically after CBD in adult goats. Brain stem tissues were collected acutely (5 days) or chronically (30 days) after sham or bilateral CBD, immunostained with antibodies targeting AMPA (GluA1 or GluA2), NMDA (GluN1), or NK-1 receptors, and optical density (OD) compared. Physiological measurement confirmed categorization of each group and showed ventilatory effects consistent with bilateral CBD (Miller et al. J Appl Physiol 115: 1088–1098, 2013). Acutely after CBD, GluA1 OD was unchanged or slightly increased, but GluA2 and GluN1 OD were reduced 15–30% within the nucleus tractus solitarius (NTS) and in other medullary respiratory nuclei. Chronically after CBD, GluA1 was reduced (P < 0.05) within the caudal NTS and in other nuclei, but there was significant recovery of GluA2 and GluN1 OD. NK1 OD was not significantly different from control after CBD. We conclude that the initial decrease in GluA2 and GluN1 after CBD likely contributes to hypoventilation and the reduced CO2 chemoreflex. The partial recovery of ventilation and the CO2 chemoreflex after CBD parallel a time-dependent return of these receptors to near control levels but likely depend upon additional initiating and maintenance factors for neuroplasticity. PMID:24790015

  15. El papel de las AMPA en la prevención de la violencia escolar

    OpenAIRE

    Silva García, Patricia

    2014-01-01

    Las Asociaciones de Padres y Madres de Alumnos (AMPA) pueden ser entidades muy útiles si son capaces de proporcionar ayudas pertinentes y oportunas en sus centros escolares. Favorecer la convivencia, objetivo prioritario en una escuela democrática, es posible cuando se construyen dispositivos adecuados de orientación, formación y apoyo para la prevención de la violencia junto con los profesionales del centro

  16. Study of recovery and stability of derivatized gliphosate and AMPA in soil using national resins

    OpenAIRE

    Souza, Tomaz Alves de; Matta, Marcia Helena de Rizzo da; Montagner, Émerson; Abreu, Adley Bergson Gonçalves de

    2006-01-01

    In the present paper we studied the recoveries of glyphosate, N-(phosphonomethyl)glycine (GLY) and its major metabolite, (aminomethyl)phosphonic acid (AMPA) in soil using national (Brazilian) ion-exchange resins, derivatization by a mixture of trifluoroacetic anhydride and trifluoroethanol and analyses by GC-MS. The quantification limits were 12 ng.g-1 for both compounds and the methodology showed a range of recuperation from 85 to 94% with coefficients of variation (CV) ranging from 4.07 to ...

  17. Excitatory amino acid transmission in health and disease

    National Research Council Canada - National Science Library

    Balázs, R; Bridges, Richard J; Cotman, Carl W

    2006-01-01

    ... Structure of the Ionotropic Glutamate Receptors, 23 3 AMPA RECEPTORS, 36 Molecular Structure, Properties, and Regulation, 36 Distribution of AMPA Receptors, 41 AMPA Receptor Pharmacology, 46 Th...

  18. Sleep deprivation impairs spatial working memory and reduces hippocampal AMPA receptor phosphorylation

    NARCIS (Netherlands)

    Hagewoud, Roelina; Havekes, Robbert; Novati, Arianna; Keijser, Jan N.; van der Zee, Eddy A.; Meerlo, Peter

    2010-01-01

    Sleep is important for brain function and cognitive performance. Sleep deprivation (SD) may affect subsequent learning capacity and ability to form new memories, particularly in the case of hippocampus-dependent tasks. In the present study we examined whether SD for 6 or 12 h during the normal

  19. Differential role of AMPA receptors in mouse tests of antidepressant and anxiolytic action

    DEFF Research Database (Denmark)

    Andreasen, Jesper T; Fitzpatrick, Ciaran M; Larsen, Maria

    2015-01-01

    and memory we also tested if GYKI-53655 disrupted performance in the V-maze test for attention-dependent behaviour, and the social transmission of food preference (STFP) test of long-term memory. LY451646 (3 mg/kg) showed an antidepressant-like profile in the FST and TST, and GYKI-53655 (≥ 5 mg/kg) had......-like effect in the FST (≥ 10 mg/kg), but not TST, an anxiolytic-like effect in the EZM (≥ 3 mg/kg) and MB test (≥ 2.5 mg/kg), and an anxiogenic-like effect in the NIH test (≥ 30 mg/kg). GYKI-53655 did not affect cognitive performance in the V-maze or STFP tests. Collectively, these findings suggest...

  20. Accumbens Shell AMPA Receptors Mediate Expression of Extinguished Reward Seeking through Interactions with Basolateral Amygdala

    Science.gov (United States)

    Millan, E. Zayra; McNally, Gavan P.

    2011-01-01

    Extinction is the reduction in drug seeking when the contingency between drug seeking behavior and the delivery of drug reward is broken. Here, we investigated a role for the nucleus accumbens shell (AcbSh). Rats were trained to respond for 4% (v/v) alcoholic beer in one context (Context A) followed by extinction in a second context (Context B).…

  1. Excitatory amino acid neurotoxicity and modulation of glutamate receptor expression in organotypic brain slice cultures

    DEFF Research Database (Denmark)

    Zimmer, J; Kristensen, Bjarne Winther; Jakobsen, B

    2000-01-01

    Using organotypic slice cultures of hippocampus and cortex-striatum from newborn to 7 day old rats, we are currently studying the excitotoxic effects of kainic acid (KA), AMPA and NMDA and the neuroprotective effects of glutamate receptor blockers, like NBQX. For detection and quantitation...

  2. Apical membrane P2Y4 purinergic receptor controls K+ secretion by strial marginal cell epithelium

    Directory of Open Access Journals (Sweden)

    Scofield Margaret A

    2005-11-01

    Full Text Available Abstract Background It was previously shown that K+ secretion by strial marginal cell epithelium is under the control of G-protein coupled receptors of the P2Y family in the apical membrane. Receptor activation by uracil nucleotides (P2Y2, P2Y4 or P2Y6 leads to a decrease in the electrogenic K+ secretion. The present study was conducted to determine the subtype of the functional purinergic receptor in gerbil stria vascularis, to test if receptor activation leads to elevation of intracellular [Ca2+] and to test if the response to these receptors undergoes desensitization. Results The transepithelial short circuit current (Isc represents electrogenic K+ secretion and was found to be decreased by uridine 5'-triphosphate (UTP, adenosine 5'-triphosphate (ATP and diadenosine tetraphosphate (Ap4A but not uridine 5'-diphosphate (UDP at the apical membrane of marginal cells of the gerbil stria vascularis. The potencies of these agonists were consistent with rodent P2Y4 and P2Y2 but not P2Y6 receptors. Activation caused a biphasic increase in intracellular [Ca2+] that could be partially blocked by 2-aminoethoxy-diphenyl borate (2-APB, an inhibitor of the IP3 receptor and store-operated channels. Suramin (100 μM did not inhibit the effect of UTP (1 μM. The ineffectiveness of suramin at the concentration used was consistent with P2Y4 but not P2Y2. Transcripts for both P2Y2 and P2Y4 were found in the stria vascularis. Sustained exposure to ATP or UTP for 15 min caused a depression of Isc that appeared to have two components but with apparently no chronic desensitization. Conclusion The results support the conclusion that regulation of K+ secretion across strial marginal cell epithelium occurs by P2Y4 receptors at the apical membrane. The apparent lack of desensitization of the response is consistent with two processes: a rapid-onset phosphorylation of KCNE1 channel subunit and a slower-onset of regulation by depletion of plasma membrane PIP2.

  3. How membrane lipids control the 3D structure and function of receptors

    OpenAIRE

    Jacques Fantini; Francisco J. Barrantes

    2018-01-01

    The cohabitation of lipids and proteins in the plasma membrane of mammalian cells is controlled by specific biochemical and biophysical rules. Lipids may be either constitutively tightly bound to cell-surface receptors (non-annular lipids) or less tightly attached to the external surface of the protein (annular lipids). The latter are exchangeable with surrounding bulk membrane lipids on a faster time scale than that of non-annular lipids. Not only do non-annular lipids bind to membrane prote...

  4. Cardiomyocytes undergo apoptosis in human immunodeficiency virus cardiomyopathy through mitochondrion- and death receptor-controlled pathways.

    Science.gov (United States)

    Twu, Cheryl; Liu, Nancy Q; Popik, Waldemar; Bukrinsky, Michael; Sayre, James; Roberts, Jaclyn; Rania, Shammas; Bramhandam, Vishnu; Roos, Kenneth P; MacLellan, W Robb; Fiala, Milan

    2002-10-29

    We investigated 18 AIDS hearts (5 with and 13 without cardiomyopathy) by using immunocytochemistry and computerized image analysis regarding the roles of HIV-1 proteins and tumor necrosis factor ligands in HIV cardiomyopathy (HIVCM). HIVCM and cardiomyocyte apoptosis were significantly related to each other and to the expression by inflammatory cells of gp120 and tumor necrosis factor-alpha. In HIVCM heart, active caspase 9, a component of the mitochondrion-controlled apoptotic pathway, and the elements of the death receptor-mediated pathway, tumor necrosis factor-alpha and Fas ligand, were expressed strongly on macrophages and weakly on cardiomyocytes. HIVCM showed significantly greater macrophage infiltration and cardiomyocyte apoptosis rate compared with non-HIVCM. HIV-1 entered cultured neonatal rat ventricular myocytes by macropinocytosis but did not replicate. HIV-1- or gp120-induced apoptosis of rat myocytes through a mitochondrion-controlled pathway, which was inhibited by heparin, AOP-RANTES, or pertussis toxin, suggesting that cardiomyocyte apoptosis is induced by signaling through chemokine receptors. In conclusion, in patients with HIVCM, cardiomyocytes die through both mitochondrion- and death receptor-controlled apoptotic pathways.

  5. Endothelin receptor-specific control of endoplasmic reticulum stress and apoptosis in the kidney.

    Science.gov (United States)

    De Miguel, Carmen; Hamrick, William C; Hobbs, Janet L; Pollock, David M; Carmines, Pamela K; Pollock, Jennifer S

    2017-02-23

    Endothelin-1 (ET-1) promotes renal damage during cardiovascular disease; yet, the molecular mechanisms involved remain unknown. Endoplasmic reticulum (ER) stress, triggered by unfolded protein accumulation in the ER, contributes to apoptosis and organ injury. These studies aimed to determine whether the ET-1 system promotes renal ER stress development in response to tunicamycin. ET B deficient (ET B def) or transgenic control (TG-con) rats were used in the presence or absence of ET A receptor antagonism. Tunicamycin treatment similarly increased cortical ER stress markers in both rat genotypes; however, only ET B def rats showed a 14-24 fold increase from baseline for medullary GRP78, sXBP-1, and CHOP. Pre-treatment of TG-con rats with the ET A blocker ABT-627 for 1 week prior to tunicamycin injection significantly reduced the ER stress response in cortex and medulla, and also inhibited renal apoptosis. Pre-treatment with ABT-627 failed to decrease renal ER stress and apoptosis in ET B def rats. In conclusion, the ET-1 system is important for the development of tunicamycin-induced renal ER stress and apoptosis. ET A receptor activation induces renal ER stress genes and apoptosis, while functional activation of the ET B receptor has protective effects. These results highlight targeting the ET A receptor as a therapeutic approach against ER stress-induced kidney injury.

  6. Size and receptor density of glutamatergic synapses: a viewpoint from left-right asymmetry of CA3-CA1 connections

    Directory of Open Access Journals (Sweden)

    Yoshiaki Shinohara

    2009-07-01

    Full Text Available Synaptic plasticity is considered to be the main mechanism for learning and memory. Excitatory synapses in the cerebral cortex and hippocampus undergo plastic changes during development and in response to electric stimulation. It is widely accepted that this process is mediated by insertion and elimination of various glutamate receptors. In a series of recent investigations on left-right asymmetry of hippocampal CA3-CA1 synapses, glutamate receptor subunits have been found to have distinctive expression patterns that depend on the postsynaptic density (PSD area. Particularly notable are the GluR1 AMPA receptor subunit and NR2B NMDA receptor subunit, where receptor density has either a supra-linear (GluR1 AMPA or inverse (NR2B NMDAR relationship to the PSD area. We review current understanding of structural and physiological synaptic plasticity and propose a scheme to classify receptor subtypes by their expression pattern with respect to PSD area.

  7. Optogenetic control of chemokine receptor signal and T-cell migration

    Science.gov (United States)

    Xu, Yuexin; Hyun, Young-Min; Lim, Kihong; Lee, Hyunwook; Cummings, Ryan J.; Gerber, Scott A.; Bae, Seyeon; Cho, Thomas Yoonsang; Lord, Edith M.; Kim, Minsoo

    2014-01-01

    Adoptive cell transfer of ex vivo-generated immune-promoting or tolerogenic T cells to either enhance immunity or promote tolerance in patients has been used with some success. However, effective trafficking of the transferred cells to the target tissue sites is the main barrier to achieving successful clinical outcomes. Here we developed a strategy for optically controlling T-cell trafficking using a photoactivatable (PA) chemokine receptor. Photoactivatable-chemokine C-X-C motif receptor 4 (PA-CXCR4) transmitted intracellular CXCR4 signals in response to 505-nm light. Localized activation of PA-CXCR4 induced T-cell polarization and directional migration (phototaxis) both in vitro and in vivo. Directing light onto the melanoma was sufficient to recruit PA-CXCR4–expressing tumor-targeting cytotoxic T cells and improved the efficacy of adoptive T-cell transfer immunotherapy, with a significant reduction in tumor growth in mice. These findings suggest that the use of photoactivatable chemokine receptors allows remotely controlled leukocyte trafficking with outstanding spatial resolution in tissues and may be feasible in other cell transfer therapies. PMID:24733886

  8. GABAB receptor cell surface export is controlled by an endoplasmic reticulum gatekeeper

    Science.gov (United States)

    Doly, Stéphane; Shirvani, Hamasseh; Gäta, Gabriel; Meye, Frank; Emerit, Michel-Boris; Enslen, Hervé; Achour, Lamia; Pardo-Lopez, Liliana; Kwon, Yang Seung; Armand, Vincent; Gardette, Robert; Giros, Bruno; Gassmann, Martin; Bettler, Bernhard; Mameli, Manuel; Darmon, Michèle; Marullo, Stefano

    2016-01-01

    Summary Endoplasmic reticulum (ER) release and cell surface export of many G protein-coupled receptors (GPCRs), are tightly regulated. For GABAB receptors of GABA, the major mammalian inhibitory neurotransmitter, the ligand-binding GB1 subunit is maintained in the ER by unknown mechanisms in the absence of hetero-dimerization with the GB2 subunit. We report that GB1 retention is regulated by a specific gatekeeper, PRAF2. This ER resident transmembrane protein binds to GB1, preventing its progression in the biosynthetic pathway. GB1 release occurs upon competitive displacement from PRAF2 by GB2. PRAF2 concentration, relative to that of GB1 and GB2, tightly controls cell surface receptor density and controls GABAB function in neurons. Experimental perturbation of PRAF2 levels in vivo caused marked hyperactivity disorders in mice. These data reveal an unanticipated major impact of specific ER gate-keepers on GPCR function and identify PRAF2 as a new molecular target with therapeutic potential for psychiatric and neurological diseases involving GABAB function. PMID:26033241

  9. The Ly49E receptor inhibits the immune control of acute Trypanosoma cruzi infection

    Directory of Open Access Journals (Sweden)

    Jessica Filtjens

    2016-11-01

    Full Text Available The protozoan parasite Trypanosoma cruzi (T. cruzi circulates in the blood upon infection and invades a variety of cells. Parasites intensively multiply during the acute phase of infection and persist lifelong at low levels in tissues and blood during the chronic phase. Natural killer (NK and NKT cells play an important role in the immune control of T. cruzi infection, mainly by releasing the cytokine IFN-γ that activates the microbicidal action of macrophages and other cells and shapes a protective type 1 immune response. The mechanisms by which immune cells are regulated to produce IFN-γ during T. cruzi infection are still incompletely understood. Here, we show that urokinase plasminogen activator (uPA is induced early upon T. cruzi infection, and remains elevated until day 20 post inoculation. We previously demonstrated that the inhibitory receptor Ly49E, which is expressed, among others, on NK and NKT cells, is triggered by uPA. Therefore, we compared wild type (WT to Ly49E knockout (KO mice for their control of experimental T. cruzi infection. Our results show that young, i.e. 4- and 6-week-old, Ly49E KO mice control the infection better than WT mice, indicated by a lower parasite load and less cachexia. The beneficial effect of Ly49E depletion is more obvious in 4-week-old male than in female mice and weakens in 8-week-old mice. In young mice, the lower T. cruzi parasitemia in Ly49E KO mice is paralleled by higher IFN-γ production compared to their WT controls. Our data indicate that Ly49E receptor expression inhibits the immune control of T. cruzi infection. This is the first demonstration that the inhibitory Ly49E receptor can interfere with the immune response to a pathogen in vivo.

  10. Leaching of glyphosate and AMPA under two soil management practices in Burgundy vineyards (Vosne-Romanee, 21-France)

    Energy Technology Data Exchange (ETDEWEB)

    Landry, David [UMR 1229 INRA/Universite de Bourgogne, Microbiologie et Geochimie des sols, Centre des Sciences de la Terre, Universite de Bourgogne, 6 bd Gabriel 21000 Dijon (France)]. E-mail: david.landry@u-bourgogne.fr; Dousset, Sylvie [UMR 1229 INRA/Universite de Bourgogne, Microbiologie et Geochimie des sols, Centre des Sciences de la Terre, Universite de Bourgogne, 6 bd Gabriel 21000 Dijon (France); Fournier, Jean-Claude [UMR 1229 INRA/Universite de Bourgogne, INRA, 17 rue Sully, 21000 Dijon (France); Andreux, Francis [UMR 1229 INRA/Universite de Bourgogne, Microbiologie et Geochimie des sols, Centre des Sciences de la Terre, Universite de Bourgogne, 6 bd Gabriel 21000 Dijon (France)

    2005-11-15

    Some drinking water reservoirs under the vineyards of Burgundy are contaminated with herbicides. Thus the effectiveness of alternative soil management practices, such as grass cover, for reducing the leaching of glyphosate and its metabolite, AMPA, through soils was studied. The leaching of both molecules was studied in structured soil columns under outdoor conditions for 1 year. The soil was managed under two vineyard soil practices: a chemically treated bare calcosol, and a vegetated calcosol. After 680 mm of rainfall, the vegetated calcosol leachates contained lower amounts of glyphosate and AMPA (0.02% and 0.03%, respectively) than the bare calcosol leachates (0.06% and 0.15%, respectively). No glyphosate and only low amounts of AMPA (<0.01%) were extracted from the soil. Glyphosate, and to a greater extent, AMPA, leach through the soils; thus, both molecules may be potential contaminants of groundwater. However, the alternative soil management practice of grass cover could reduce groundwater contamination by the pesticide. - Glyphosate and AMPA leached in greater amounts through a chemically treated bare calcosol than through a vegetated calcosol.

  11. Leaching of glyphosate and AMPA under two soil management practices in Burgundy vineyards (Vosne-Romanee, 21-France)

    International Nuclear Information System (INIS)

    Landry, David; Dousset, Sylvie; Fournier, Jean-Claude; Andreux, Francis

    2005-01-01

    Some drinking water reservoirs under the vineyards of Burgundy are contaminated with herbicides. Thus the effectiveness of alternative soil management practices, such as grass cover, for reducing the leaching of glyphosate and its metabolite, AMPA, through soils was studied. The leaching of both molecules was studied in structured soil columns under outdoor conditions for 1 year. The soil was managed under two vineyard soil practices: a chemically treated bare calcosol, and a vegetated calcosol. After 680 mm of rainfall, the vegetated calcosol leachates contained lower amounts of glyphosate and AMPA (0.02% and 0.03%, respectively) than the bare calcosol leachates (0.06% and 0.15%, respectively). No glyphosate and only low amounts of AMPA (<0.01%) were extracted from the soil. Glyphosate, and to a greater extent, AMPA, leach through the soils; thus, both molecules may be potential contaminants of groundwater. However, the alternative soil management practice of grass cover could reduce groundwater contamination by the pesticide. - Glyphosate and AMPA leached in greater amounts through a chemically treated bare calcosol than through a vegetated calcosol

  12. Phrenic motoneuron expression of serotonergic and glutamatergic receptors following upper cervical spinal cord injury

    Science.gov (United States)

    Mantilla, Carlos B.; Bailey, Jeffrey P.; Zhan, Wen-Zhi; Sieck, Gary C.

    2012-01-01

    Following cervical spinal cord injury at C2 (SH hemisection model) there is progressive recovery of phrenic activity. Neuroplasticity in the postsynaptic expression of neurotransmitter receptors may contribute to functional recovery. Phrenic motoneurons express multiple serotonergic (5-HTR) and glutamatergic (GluR) receptors, but the timing and possible role of these different neurotransmitter receptor subtypes in the neuroplasticity following SH are not clear. The current study was designed to test the hypothesis that there is an increased expression of serotonergic and glutamatergic neurotransmitter receptors within phrenic motoneurons after SH. In adult male rats, phrenic motoneurons were labeled retrogradely by intrapleural injection of Alexa 488-conjugated cholera toxin B. In thin (10 μm) frozen sections of the spinal cord, fluorescently-labeled phrenic motoneurons were visualized for laser capture microdissection (LCM). Using quantitative real-time RT-PCR in LCM samples, the time course of changes in 5-HTR and GluR mRNA expression was determined in phrenic motoneurons up to 21 days post-SH. Expression of 5-HTR subtypes 1b, 2a and 2c and GluR subtypes AMPA, NMDA, mGluR1 and mGluR5 was evident in phrenic motoneurons from control and SH rats. Phrenic motoneuron expression of 5-HTR2a increased ~8-fold (relative to control) at 14 days post-SH, whereas NMDA expression increased ~16-fold by 21-days post-SH. There were no other significant changes in receptor expression at any time post-SH. This is the first study to systematically document changes in motoneuron expression of multiple neurotransmitter receptors involved in regulation of motoneuron excitability. By providing information on the neuroplasticity of receptors expressed in a motoneuron pool that is inactivated by a higher-level spinal cord injury, appropriate pharmacological targets can be identified to alter motoneuron excitability. PMID:22227062

  13. 1H-cyclopentapyrimidine-2,4(1H,3H)-dione-related ionotropic glutamate receptors ligands. Structure-activity relationships and identification of potent and selective iGluR5 modulators

    DEFF Research Database (Denmark)

    Butini, Stefania; Pickering, Darryl S; Morelli, Elena

    2008-01-01

    (S)-CPW399 ((S)-1) is a potent and excitotoxic AMPA receptor partial agonist. Modifying the cyclopentane ring of (S)-1, we developed two of the most potent and selective functional antagonists (5 and 7) for kainate receptor (KA-R) subunit iGluR5. Derivatives 5 and 7, with their unique pharmacolog...

  14. Thyrotropin receptor autoantibodies and early miscarriages in patients with Hashimoto thyroiditis: a case-control study.

    Science.gov (United States)

    Toulis, Konstantinos A; Goulis, Dimitrios G; Tsolakidou, Konstantina; Hilidis, Ilias; Fragkos, Marios; Polyzos, Stergios A; Gerofotis, Antonios; Kita, Marina; Bili, Helen; Vavilis, Dimitrios; Daniilidis, Michail; Tarlatzis, Basil C; Papadimas, Ioannis

    2013-08-01

    We have previously hypothesized that early miscarriage in women with Hashimoto thyroiditis might be the result of a cross-reactivity process, in which blocking autoantibodies against thyrotropin receptor (TSHr-Ab) antagonize hCG action on its receptor on the corpus luteum. To test this hypothesis from the clinical perspective, we investigated the presence of TSHr-Ab in Hashimoto thyroiditis patients with apparently unexplained, first-trimester recurrent miscarriages compared to that in Hashimoto thyroiditis patients with documented normal fertility. A total of 86 subjects (43 cases and 43 age-matched controls) were finally included in a case-control study. No difference in the prevalence of TSHr-Ab positivity was detected between cases and controls (Fisher's exact test, p value = 1.00). In patients with recurrent miscarriages, TSHr-Ab concentrations did not predict the number of miscarriages (univariate linear regression, p value = 0.08). These results were robust in sensitivity analyses, including only cases with full investigation or those with three or more miscarriages. We conclude that no role could be advocated for TSHr-Ab in the aetiology of recurrent miscarriages in women with Hashimoto thyroiditis.

  15. Perirhinal Cortex Muscarinic Receptor Blockade Impairs Taste Recognition Memory Formation

    OpenAIRE

    Gutiérrez, Ranier; De la Cruz, Vanesa; Rodriguez-Ortiz, Carlos J.; Bermudez-Rattoni, Federico

    2004-01-01

    The relevance of perirhinal cortical cholinergic and glutamatergic neurotransmission for taste recognition memory and learned taste aversion was assessed by microinfusions of muscarinic (scopolamine), NMDA (AP-5), and AMPA (NBQX) receptor antagonists. Infusions of scopolamine, but not AP5 or NBQX, prevented the consolidation of taste recognition memory using attenuation of neophobia as an index. In addition, learned taste aversion in both short- and long-term memory tests was exclusively impa...

  16. POTENSI DARI KAPANG Aspergilus niger, Rhizophus oryzae DAN Neurospora sitophila SEBAGAI PENGHASIL EZIM FITASE DAN AMILASE PADA SUBSTRATE AMPAS TAHU

    Directory of Open Access Journals (Sweden)

    Atit - Kanti

    2017-02-01

    Full Text Available Penambahan enzim hidrolisis untuk pakan ternak dapat meningkatkan nilai nutrisi pakan. Penelitian bertujuan untuk mendapatkan kondisi optimal untuk produksi enzim amilase dan fitase pada media ampas tahu menggunakan Aspergilus niger, Rhizophus oryzae dan Neurospora sitophila. Uji kemampuan produksi enzim fitase dan amilase oleh Aspergilus niger, Rhizophus oryzae dan Neurospora sitophila dilakukan menggunakan media ampas tahu yang disterilisasi. Pemilihan ketiga isolat ini diawali dengan uji produksi enzim amilase pada kultur cair yang mengandung 2 % pati, dan uji fitase dilakukan pada media yang mengandung 0.5 % sodium fitat. Hasil uji pada medium cair selanjutnya digunakan untuk uji produksi enzim fitase dan fitase pada sistem fermentasi padat (SSF menggunakan ampas tahu sebagai media fermentasi. Untuk mendapatkan produksi enzim yang tinggi dilakukan melalui optimasi waktu inkubasi, suhu inkubasi dan pH media. Fitase dan amilase dapat diproduksi dengan media ampas tahu oleh R. oryzae, A. niger dan N. sitophila. Kondisi optimum untuk produksi fitase, yaitu waktu inkubasi pada hari keempat untuk ketiga kapang, suhu 25 °C untuk R. oryzae dan A. niger, suhu 30°C untuk N. sitophila, pH 8 untuk R. oryzae, pH 6 untuk Aspergillus niger dan N. Sitophila. Neurospora sitophila menghasilkan amilase optimum pada suhu 35°C, sedangkan Aspergillus niger dan Rhizopus oryzae optimum pada suhu 30°C. Penurunan aktivitas produksi amilase menurun oleh R. oryzae pada suhu 40°C. Amilase diproduksi optimal pada pH 6-7. Pakan ternak yang mengandung asam fitat mampu dihidrolisis oleh fitase pada kondisi optimum. Ketiga kapang juga menghasilkan enzim amilase pada media ampas tahu mengindikasikan bahwa ampas tahu merupakan susbtrat yang baik untuk produksi enzim hidrolisis yang berguna untuk meningkatkan nilai nutrisi pakan ternak. (Kata kunci: Amilase, Aspergilus niger, Neurospora sitophila, phytase, Rhizophus oryzae

  17. Positive modulation of glutamatergic receptors potentiates the suppressive effects of antipsychotics on conditioned avoidance responding in rats

    DEFF Research Database (Denmark)

    Olsen, Christina Kurre; Kreilgaard, Mads; Didriksen, Michael

    2006-01-01

    .c.), olanzapine (0.63 mg/kg, s.c.) and clozapine (1.3 mg/kg, s.c.) without causing additional motor disturbances. Thus, the adjunct enhancement of NMDA or AMPA receptor function observed clinically, appears reflected in the present rat CAR study. Consequently, our data lend further support to the potential use...

  18. Striatal Dopamine D2/D3 Receptor Availability Is Associated with Executive Function in Healthy Controls but Not Methamphetamine Users.

    Directory of Open Access Journals (Sweden)

    Michael E Ballard

    Full Text Available Dopamine D2/D3 receptor availability in the striatum has been linked with executive function in healthy individuals, and is below control levels among drug addicts, possibly contributing to diminished executive function in the latter group. This study tested for an association of striatal D2/D3 receptor availability with a measure of executive function among research participants who met DSM-IV criteria for methamphetamine dependence.Methamphetamine users and non-user controls (n = 18 per group completed the Wisconsin Card Sorting Test and positron emission tomography with [18F]fallypride.The methamphetamine users displayed significantly lower striatal D2/D3 receptor availability on average than controls after controlling for age and education (p = 0.008, but they did not register greater proportions of either perseverative or non-perseverative errors when controlling for education (both ps ≥ 0.622. The proportion of non-perseverative, but not perseverative, errors was negatively correlated with striatal D2/D3 receptor availability among controls (r = -0.588, p = 0.010, but not methamphetamine users (r = 0.281, p = 0.258, and the group-wise interaction was significant (p = 0.030.These results suggest that cognitive flexibility, as measured by perseverative errors on the Wisconsin Card Sorting Test, is not determined by signaling through striatal D2/D3 receptors in healthy controls, and that in stimulant abusers, who have lower D2/D3 receptor availability, compensation can effectively maintain other executive functions, which are associated with D2/D3 receptor signaling in controls.

  19. Receptor activation and 2 distinct COOH-terminal motifs control G-CSF receptor distribution and internalization kinetics

    NARCIS (Netherlands)

    L.H.J. Aarts (Bart); O. Roovers (Onno); A.C. Ward (Alister); I.P. Touw (Ivo)

    2004-01-01

    textabstractWe have studied the intracellular distribution and internalization kinetics of the granulocyte colony-stimulating factor receptor (G-CSF-R) in living cells using fusion constructs of wild-type or mutant G-CSF-R and enhanced green fluorescent protein (EGFP). Under

  20. Serotonin Signaling in Schistosoma mansoni: A Serotonin–Activated G Protein-Coupled Receptor Controls Parasite Movement

    Science.gov (United States)

    Rashid, Mohammed; Ribeiro, Paula

    2014-01-01

    Serotonin is an important neuroactive substance in all the parasitic helminths. In Schistosoma mansoni, serotonin is strongly myoexcitatory; it potentiates contraction of the body wall muscles and stimulates motor activity. This is considered to be a critical mechanism of motor control in the parasite, but the mode of action of serotonin is poorly understood. Here we provide the first molecular evidence of a functional serotonin receptor (Sm5HTR) in S. mansoni. The schistosome receptor belongs to the G protein-coupled receptor (GPCR) superfamily and is distantly related to serotonergic type 7 (5HT7) receptors from other species. Functional expression studies in transfected HEK 293 cells showed that Sm5HTR is a specific serotonin receptor and it signals through an increase in intracellular cAMP, consistent with a 5HT7 signaling mechanism. Immunolocalization studies with a specific anti-Sm5HTR antibody revealed that the receptor is abundantly distributed in the worm's nervous system, including the cerebral ganglia and main nerve cords of the central nervous system and the peripheral innervation of the body wall muscles and tegument. RNA interference (RNAi) was performed both in schistosomulae and adult worms to test whether the receptor is required for parasite motility. The RNAi-suppressed adults and larvae were markedly hypoactive compared to the corresponding controls and they were also resistant to exogenous serotonin treatment. These results show that Sm5HTR is at least one of the receptors responsible for the motor effects of serotonin in S. mansoni. The fact that Sm5HTR is expressed in nerve tissue further suggests that serotonin stimulates movement via this receptor by modulating neuronal output to the musculature. Together, the evidence identifies Sm5HTR as an important neuronal protein and a key component of the motor control apparatus in S. mansoni. PMID:24453972

  1. Studying cerebellar circuits by remote control of selected neuronal types with GABA-A receptors

    Directory of Open Access Journals (Sweden)

    William Wisden

    2009-12-01

    Full Text Available Although GABA-A receptor-mediated inhibition of cerebellar Purkinje cells by molecular layer interneurons (MLIs has been studied intensely on the cellular level, it has remained unclear how this inhibition regulates cerebellum-dependent behaviour. We have implemented two complementary approaches to investigate the function of the MLI-Purkinje cell synapse on the behavioral level. In the first approach we permanently disrupted inhibitory fast synaptic transmission at the synapse by genetically removing the postsynaptic GABA-A receptors from Purkinje cells (PC-Δγ2 mice. We found that chronic disruption of the MLI-Purkinje cell synapse strongly impaired cerebellar learning of the vestibular occular reflex (VOR, presumably by disrupting the temporal patterns of Purkinje cell activity. However, in PC-Δγ2 mice the baseline VOR reflex was only mildly affected; indeed PC-Δγ2 mice showed no ataxia or gait abnormalities suggesting that MLI control of Purkinje cell activity is either not involved in ongoing motor tasks or that the system has found a way to compensate for its loss. To investigate the latter possibility we have developed an alternative genetic technique; we made the MLI-Purkinje cell synapse selectively sensitive to rapid manipulation with the GABAA receptor modulator zolpidem (PC-γ2-swap mice. Minutes after intraperitoneal zolpidem injection, these PC-γ2-swap mice developed severe motor abnormalities, revealing a substantial contribution of the MLI-Purkinje cell synapse to real time motor control. The cell-type selective permanent knockout of synaptic GABAergic input, and the fast reversible modulation of GABAergic input at the same synapse illustrate how pursuing both strategies gives a fuller view.

  2. Controlled-Deactivation CB1 Receptor Ligands as a Novel Strategy to Lower Intraocular Pressure

    Directory of Open Access Journals (Sweden)

    Sally Miller

    2018-05-01

    Full Text Available Nearly half a century has passed since the demonstration that cannabis and its chief psychoactive component Δ9-THC lowers intraocular pressure (IOP. Elevated IOP remains the chief hallmark and therapeutic target for glaucoma, a condition that places millions at risk of blindness. It is likely that Δ9-THC exerts much of its IOP-lowering effects via the activation of CB1 cannabinoid receptors. However, the initial promise of CB1 as a target for treating glaucoma has not thus far translated into a credible therapeutic strategy. We have recently shown that blocking monoacylglycerol lipase (MAGL, an enzyme that breaks the endocannabinoid 2-arachidonoyl glycerol (2-AG, substantially lowers IOP. Another strategy is to develop cannabinoid CB1 receptor agonists that are optimized for topical application to the eye. Recently we have reported on a controlled-deactivation approach where the “soft” drug concept of enzymatic deactivation was combined with a “depot effect” that is commonly observed with Δ9-THC and other lipophilic cannabinoids. This approach allowed us to develop novel cannabinoids with a predictable duration of action and is particularly attractive for the design of CB1 activators for ophthalmic use with limited or no psychoactive effects. We have tested a novel class of compounds using a combination of electrophysiology in autaptic hippocampal neurons, a well-characterized model of endogenous cannabinoid signaling, and measurements of IOP in a mouse model. We now report that AM7410 is a reasonably potent and efficacious agonist at CB1 in neurons and that it substantially (30% lowers IOP for as long as 5 h after a single topical treatment. This effect is absent in CB1 knockout mice. Our results indicate that the direct targeting of CB1 receptors with controlled-deactivation ligands is a viable approach to lower IOP in a murine model and merits further study in other model systems.

  3. Identification of G Protein-Coupled Receptors (GPCRs in Primary Cilia and Their Possible Involvement in Body Weight Control.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Omori

    Full Text Available Primary cilia are sensory organelles that harbor various receptors such as G protein-coupled receptors (GPCRs. We analyzed subcellular localization of 138 non-odorant GPCRs. We transfected GPCR expression vectors into NIH3T3 cells, induced ciliogenesis by serum starvation, and observed subcellular localization of GPCRs by immunofluorescent staining. We found that several GPCRs whose ligands are involved in feeding behavior, including prolactin-releasing hormone receptor (PRLHR, neuropeptide FF receptor 1 (NPFFR1, and neuromedin U receptor 1 (NMUR1, localized to the primary cilia. In addition, we found that a short form of dopamine receptor D2 (DRD2S is efficiently transported to the primary cilia, while a long form of dopamine receptor D2 (DRD2L is rarely transported to the primary cilia. Using an anti-Prlhr antibody, we found that Prlhr localized to the cilia on the surface of the third ventricle in the vicinity of the hypothalamic periventricular nucleus. We generated the Npy2r-Cre transgenic mouse line in which Cre-recombinase is expressed under the control of the promoter of Npy2r encoding a ciliary GPCR. By mating Npy2r-Cre mice with Ift80 flox mice, we generated Ift80 conditional knockout (CKO mice in which Npy2r-positive cilia were diminished in number. We found that Ift80 CKO mice exhibited a body weight increase. Our results suggest that Npy2r-positive cilia are important for body weight control.

  4. Identification of G Protein-Coupled Receptors (GPCRs) in Primary Cilia and Their Possible Involvement in Body Weight Control.

    Science.gov (United States)

    Omori, Yoshihiro; Chaya, Taro; Yoshida, Satoyo; Irie, Shoichi; Tsujii, Toshinori; Furukawa, Takahisa

    2015-01-01

    Primary cilia are sensory organelles that harbor various receptors such as G protein-coupled receptors (GPCRs). We analyzed subcellular localization of 138 non-odorant GPCRs. We transfected GPCR expression vectors into NIH3T3 cells, induced ciliogenesis by serum starvation, and observed subcellular localization of GPCRs by immunofluorescent staining. We found that several GPCRs whose ligands are involved in feeding behavior, including prolactin-releasing hormone receptor (PRLHR), neuropeptide FF receptor 1 (NPFFR1), and neuromedin U receptor 1 (NMUR1), localized to the primary cilia. In addition, we found that a short form of dopamine receptor D2 (DRD2S) is efficiently transported to the primary cilia, while a long form of dopamine receptor D2 (DRD2L) is rarely transported to the primary cilia. Using an anti-Prlhr antibody, we found that Prlhr localized to the cilia on the surface of the third ventricle in the vicinity of the hypothalamic periventricular nucleus. We generated the Npy2r-Cre transgenic mouse line in which Cre-recombinase is expressed under the control of the promoter of Npy2r encoding a ciliary GPCR. By mating Npy2r-Cre mice with Ift80 flox mice, we generated Ift80 conditional knockout (CKO) mice in which Npy2r-positive cilia were diminished in number. We found that Ift80 CKO mice exhibited a body weight increase. Our results suggest that Npy2r-positive cilia are important for body weight control.

  5. Dopamine D(1) receptor-mediated control of striatal acetylcholine release by endogenous dopamine.

    Science.gov (United States)

    Acquas, E; Di Chiara, G

    1999-10-27

    The role of dopamine D(1) and D(2) receptors in the control of acetylcholine release in the dorsal striatum by endogenous dopamine was investigated by monitoring with microdialysis the effect of the separate or combined administration of the dopamine D(1) receptor antagonist, SCH 39166 ¿(-)-trans-6,7,7a,8,9, 13b-exahydro-3-chloro-2-hydroxy-N-methyl-5H-benzo-[d]-nap hto-[2, 1b]-azepine hydrochloride¿ (50 microg/kg subcutaneous (s.c.)), of the dopamine D(2)/D(3) receptor agonist, quinpirole (trans-(-)-4aR, 4a,5,6,7,8,8a,9-octahydro-5-propyl-1H-pyrazolo-(3,4-g)-quinoline hydrochloride) (5 and 10 microg/kg s.c.), and of the D(3) receptor selective agonist, PD 128,907 [S(+)-(4aR,10bR)-3,4,4a, 10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano-[4,3-b]-1,4-oxazin -9-ol hydrochloride] (50 microg/kg s.c.), on in vivo dopamine and acetylcholine release. Microdialysis was performed with a Ringer containing low concentrations (0.01 microM) of the acetylcholinesterase inhibitor, neostigmine. Quinpirole (10 microg/kg s.c.) decreased striatal dopamine and acetylcholine release. Administration of PD 128,907 (50 microg/kg) decreased dopamine but failed to affect acetylcholine release. SCH 39166 (50 microg/kg s.c.) stimulated dopamine release and reduced acetylcholine release. Pretreatment with quinpirole reduced (5 microg/kg s.c.) or completely prevented (10 microg/kg s.c.) the stimulation of dopamine release elicited by SCH 39166 (50 microg/kg s.c.); on the other hand, pretreatment with quinpirole (5 and 10 microg/kg) potentiated the reduction of striatal acetylcholine release induced by SCH 39166 (50 microg/kg s.c.). Similarly, pretreatment with PD 128,907 (50 microg/kg) which prevented the increase of dopamine release induced by SCH 39166 (50 microg/kg), potentiated the reduction of striatal acetylcholine transmission elicited by SCH 39166. Thus, pretreatment with low doses of quinpirole or PD 128,907 influences in opposite manner the effect of SCH 39166 on striatal dopamine and

  6. Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

    Science.gov (United States)

    Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

    2018-05-01

    The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

  7. Growth and gene expression are predominantly controlled by distinct regions of the human IL-4 receptor.

    Science.gov (United States)

    Ryan, J J; McReynolds, L J; Keegan, A; Wang, L H; Garfein, E; Rothman, P; Nelms, K; Paul, W E

    1996-02-01

    IL-4 causes hematopoietic cells to proliferate and express a series of genes, including CD23. We examined whether IL-4-mediated growth, as measured by 4PS phosphorylation, and gene induction were similarly controlled. Studies of M12.4.1 cells expressing human IL-4R truncation mutants indicated that the region between amino acids 557-657 is necessary for full gene expression, which correlated with Stat6 DNA binding activity. This region was not required for 4PS phosphorylation. Tyrosine-to-phenylalanine mutations in the interval between amino acids 557-657 revealed that as long as one tyrosine remained unmutated, CD23 was fully induced. When all three tyrosines were mutated, the receptor was unable to induce CD23. The results indicate that growth regulation and gene expression are principally controlled by distinct regions of IL-4R.

  8. Hidrolisis Ampas Tebu dengan Katalisator Asam Asetat untuk Memproduksi Furfural menggunakan Metode Steam Stripping

    Directory of Open Access Journals (Sweden)

    Nita Listiani

    2016-12-01

    Full Text Available Proses hidrolisis ampas tebu menggunakan asam asetat sebagai katalis dengan metode satu tahap (steam stripping telah dilakukan. Ampas tebu sebanyak 50 gram dihidrolisis dalam 500 ml akuades yang mengandung katalis asam asetat sebesar 2 - 6% dengan variabel waktu selama 1 - 3 jam dan temperatur hidrolisis 110 - 120oC menggunakan metode steam stripping. Metode konvensional dilakukan dalam dua tahap yaitu pemasakan dan pemisahan dalam waktu tinggal tertentu, sehingga dapat menyebabkan degradasi furfural. Selain itu, energi yang digunakan sangat besar karena ada energi yang terbuang saat pendinginan produk. Maka peneliti mengembangkan proses hidrolisis hemiselulosa menjadi furfural sekaligus juga proses pemisahan yang dilakukan secara serempak dalam satu tahap yaitu dengan menggunakan metode distilasi steam stripping. Penelitian ini ditujukan untuk melihat apakah metode steam stripping dengan menggunakan katalis asam asetat efektif untuk digunakan dalam memproduksi furfural. Dalam studi ini juga dipelajari pengaruh waktu hidrolisis, konsentrasi katalis, dan  temperatur terhadap konsentrasi furfural. Hasil uji menggunakan Response Surface Methodology (RSM menunjukkan bahwa variabel yang paling berpengaruh untuk perolehan furfural adalah konsentrasi katalis dan temperatur. Hasil penelitian menunjukkan optimum dengan perolehan konsentrasi furfural tertinggi (6,038 mg/ml di peroleh pada waktu 3 jam, temperatur 120°C, dan konsentrasi katalis 6%. Hasil penelitian menunjukkan bahwa metode ini efektif untuk digunakan dalam produksi furfural.

  9. Prefrontal gamma-aminobutyric acid type A receptor insertion controls cue-induced relapse to nicotine seeking.

    Science.gov (United States)

    Lubbers, Bart R; van Mourik, Yvar; Schetters, Dustin; Smit, August B; De Vries, Taco J; Spijker, Sabine

    2014-11-01

    Current smoking cessation therapies offer limited success, as relapse rates remain high. Nicotine, which is the major component of tobacco smoke, is thought to be primarily responsible for the addictive properties of tobacco. However, little is known about the molecular mechanisms underlying nicotine relapse, hampering development of more effective therapies. The objective of this study was to elucidate the role of medial prefrontal cortex (mPFC) glutamatergic and gamma-aminobutyric acid (GABA)ergic receptors in controlling relapse to nicotine seeking. Using an intravenous self-administration model, we studied glutamate and gamma-aminobutyric acid receptor regulation in the synaptic membrane fraction of the rat mPFC following extinction and cue-induced relapse to nicotine seeking. Subsequently, we locally intervened at the level of GABAergic signaling by using a mimetic peptide of the GABA receptor associated protein-interacting domain of GABA type A (GABAA) receptor subunit γ2 (TAT-GABAγ2) and muscimol, a GABAA receptor agonist. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and N-methyl-D-aspartate receptors were not regulated after the 30-min relapse test. However, GABAA receptor subunits α1 and γ2 were upregulated, and interference with GABAA receptor insertion in the cell membrane using the TAT-GABAγ2 peptide in the dorsal mPFC, but not the ventral mPFC, significantly increased responding during relapse. Increasing GABAA transmission with muscimol in the dorsal and ventral mPFC attenuated relapse. These data indicate that cue-induced relapse entails a GABAergic plasticity mechanism that limits nicotine seeking by restoring inhibitory control in the dorsal mPFC. GABAA receptor-mediated neurotransmission in the dorsal mPFC constitutes a possible future therapeutic target for maintaining smoking abstinence. Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  10. Oestrogen receptor α gene haplotype and postmenopausal breast cancer risk: a case control study

    International Nuclear Information System (INIS)

    Wedrén, Sara; Stiger, Fredrik; Persson, Ingemar; Baron, John; Weiderpass, Elisabete; Lovmar, Lovisa; Humphreys, Keith; Magnusson, Cecilia; Melhus, Håkan; Syvänen, Ann-Christine; Kindmark, Andreas; Landegren, Ulf; Fermér, Maria Lagerström

    2004-01-01

    Oestrogen receptor α, which mediates the effect of oestrogen in target tissues, is genetically polymorphic. Because breast cancer development is dependent on oestrogenic influence, we have investigated whether polymorphisms in the oestrogen receptor α gene (ESR1) are associated with breast cancer risk. We genotyped breast cancer cases and age-matched population controls for one microsatellite marker and four single-nucleotide polymorphisms (SNPs) in ESR1. The numbers of genotyped cases and controls for each marker were as follows: TA n , 1514 cases and 1514 controls; c.454-397C → T, 1557 cases and 1512 controls; c.454-351A → G, 1556 cases and 1512 controls; c.729C → T, 1562 cases and 1513 controls; c.975C → G, 1562 cases and 1513 controls. Using logistic regression models, we calculated odds ratios (ORs) and 95% confidence intervals (CIs). Haplotype effects were estimated in an exploratory analysis, using expectation-maximisation algorithms for case-control study data. There were no compelling associations between single polymorphic loci and breast cancer risk. In haplotype analyses, a common haplotype of the c.454-351A → G or c.454-397C → T and c.975C → G SNPs appeared to be associated with an increased risk for ductal breast cancer: one copy of the c.454-351A → G and c.975C → G haplotype entailed an OR of 1.19 (95% CI 1.06–1.33) and two copies with an OR of 1.42 (95% CI 1.15–1.77), compared with no copies, under a model of multiplicative penetrance. The association with the c.454-397C → T and c.975C → G haplotypes was similar. Our data indicated that these haplotypes were more influential in women with a high body mass index. Adjustment for multiple comparisons rendered the associations statistically non-significant. We found suggestions of an association between common haplotypes in ESR1 and the risk for ductal breast cancer that is stronger in heavy women

  11. Interacting cannabinoid and opioid receptors in the nucleus accumbens core control adolescent social play

    Directory of Open Access Journals (Sweden)

    Antonia Manduca

    2016-11-01

    Full Text Available Social play behavior is a highly rewarding, developmentally important form of social interaction in young mammals. However, its neurobiological underpinnings remain incompletely understood. Previous work has suggested that opioid and endocannabinoid neurotransmission interact in the modulation of social play. Therefore, we combined behavioral, pharmacological, electrophysiological and genetic approaches to elucidate the role of the endocannabinoid 2-arachidonoylglycerol (2-AG in social play, and how cannabinoid and opioid neurotransmission interact to control social behavior in adolescent rodents. Systemic administration of the 2-AG hydrolysis inhibitor JZL184 or the opioid receptor agonist morphine increased social play behavior in adolescent rats. These effects were blocked by systemic pretreatment with either CB1 cannabinoid receptor (CB1R or mu-opioid receptor (MOR antagonists. The social play-enhancing effects of systemic morphine or JZL184 treatment were also prevented by direct infusion of the CB1R antagonist SR141716 and the MOR antagonist naloxone into the nucleus accumbens core (NAcC. Searching for synaptic correlates of these effects in adolescent NAcC excitatory synapses, we observed that CB1R antagonism blocked the effect of the MOR agonist DAMGO and, conversely, that naloxone reduced the effect of a cannabinoid agonist. These results were recapitulated in mice, and completely abolished in CB1R and MOR knockout mice, suggesting that the functional interaction between CB1R and MOR in the NAcC in the modulation of mediates social behavior is widespread in rodents. The data shed new light on the mechanism by which endocannabinoid lipids and opioid peptides interact to orchestrate rodent socioemotional behaviors.

  12. Involvement of β3-adrenergic receptors in the control of food intake in rats.

    Science.gov (United States)

    Kanzler, S A; Januario, A C; Paschoalini, M A

    2011-11-01

    This study examined the food intake changes evoked by intracerebroventricular (icv) injection of a selective agonist (BRL37344, 2 and 20 nmol) or antagonist (SR59230A, 10 and 50 nmol) of β3-adrenergic receptors in 24-h fasted rats (adult male Wistar rats, 200-350 g, N = 6/treatment). The animals were also pretreated with saline icv (SAL) or SR59230A (50 nmol) followed by BRL37344 (20 nmol) or SAL in order to determine the selectivity of the effects evoked by BRL37344 on food intake or the selectivity of the effects evoked by SR59230A on risk assessment (RA) behavior. The highest dose of BRL37344 (N = 7) decreased food intake 1 h after the treatment (6.4 ± 0.5 g in SAL-treated vs 4.2 ± 0.8 g in drug-treated rats). While both doses of SR59230A failed to affect food intake (5.1 ± 1.1 g for 10 nmol and 6.0 ± 1.8 g for 50 nmol), this treatment reduced the RA frequency (number/30 min) (4 ± 2 for SAL-treated vs 1 ± 1 for 10 nmol and 0.5 ± 1 for 50 nmol SR59230A-treated rats), an ethological parameter related to anxiety. While pretreatment with SR59230A (7.0 ± 0.5 g) abolished the hypophagia induced by BRL37344 (3.6 ± 0.9 g), BRL37344 suppressed the reduction in RA frequency caused by SR59230A. These results show that the hypophagia caused by BRL37344 is selectively mediated by β3-adrenergic receptors within the central nervous system. Moreover, they suggest the involvement of these receptors in the control of anxiety.

  13. Involvement of β3-adrenergic receptors in the control of food intake in rats

    Directory of Open Access Journals (Sweden)

    S.A. Kanzler

    2011-11-01

    Full Text Available This study examined the food intake changes evoked by intracerebroventricular (icv injection of a selective agonist (BRL37344, 2 and 20 nmol or antagonist (SR59230A, 10 and 50 nmol of β3-adrenergic receptors in 24-h fasted rats (adult male Wistar rats, 200-350 g, N = 6/treatment. The animals were also pretreated with saline icv (SAL or SR59230A (50 nmol followed by BRL37344 (20 nmol or SAL in order to determine the selectivity of the effects evoked by BRL37344 on food intake or the selectivity of the effects evoked by SR59230A on risk assessment (RA behavior. The highest dose of BRL37344 (N = 7 decreased food intake 1 h after the treatment (6.4 ± 0.5 g in SAL-treated vs 4.2 ± 0.8 g in drug-treated rats. While both doses of SR59230A failed to affect food intake (5.1 ± 1.1 g for 10 nmol and 6.0 ± 1.8 g for 50 nmol, this treatment reduced the RA frequency (number/30 min (4 ± 2 for SAL-treated vs 1 ± 1 for 10 nmol and 0.5 ± 1 for 50 nmol SR59230A-treated rats, an ethological parameter related to anxiety. While pretreatment with SR59230A (7.0 ± 0.5 g abolished the hypophagia induced by BRL37344 (3.6 ± 0.9 g, BRL37344 suppressed the reduction in RA frequency caused by SR59230A. These results show that the hypophagia caused by BRL37344 is selectively mediated by β3-adrenergic receptors within the central nervous system. Moreover, they suggest the involvement of these receptors in the control of anxiety.

  14. Spatial glyphosate and AMPA redistribution on the soil surface driven by sediment transport processes – A flume experiment

    NARCIS (Netherlands)

    Bento, Célia P.M.; Commelin, Meindert C.; Baartman, Jantiene E.M.; Yang, Xiaomei; Peters, Piet; Mol, Hans G.J.; Ritsema, Coen J.; Geissen, Violette

    2018-01-01

    This study investigates the influence of small-scale sediment transport on glyphosate and AMPA redistribution on the soil surface and on their off-site transport during water erosion events. Both a smooth surface (T1) and a surface with “seeding lines on the contour” (T2) were tested in a rainfall

  15. Estrogen receptor alpha gene polymorphism and endometrial cancer risk – a case-control study

    International Nuclear Information System (INIS)

    Wedrén, Sara; Stiger, Fredrik; Persson, Ingemar; Baron, John A; Weiderpass, Elisabete; Lovmar, Lovisa; Humphreys, Keith; Magnusson, Cecilia; Melhus, Håkan; Syvänen, Ann-Christine; Kindmark, Andreas; Landegren, Ulf; Fermér, Maria Lagerström

    2008-01-01

    Estrogen is an established endometrial carcinogen. One of the most important mediators of estrogenic action is the estrogen receptor alpha. We have investigated whether polymorphic variation in the estrogen receptor alpha gene (ESR1) is associated with endometrial cancer risk. In 702 cases with invasive endometrial cancer and 1563 controls, we genotyped five markers in ESR1 and used logistic regression models to estimate odds ratios (OR) and 95 percent confidence intervals (CI). We found an association between rs2234670, rs2234693, as well as rs9340799, markers in strong linkage disequilibrium (LD), and endometrial cancer risk. The association with rs9340799 was the strongest, OR 0.75 (CI 0.60–0.93) for heterozygous and OR 0.53 (CI 0.37–0.77) for homozygous rare compared to those homozygous for the most common allele. Haplotype models did not fit better to the data than single marker models. We found that intronic variation in ESR1 was associated with endometrial cancer risk

  16. Prokineticin receptor 1 as a novel suppressor of preadipocyte proliferation and differentiation to control obesity.

    Directory of Open Access Journals (Sweden)

    Cécilia Szatkowski

    Full Text Available BACKGROUND: Adipocyte renewal from preadipocytes occurs throughout the lifetime and contributes to obesity. To date, little is known about the mechanisms that control preadipocyte proliferation and differentiation. Prokineticin-2 is an angiogenic and anorexigenic hormone that activate two G protein-coupled receptors (GPCRs: PKR1 and PKR2. Prokineticin-2 regulates food intake and energy metabolism via central mechanisms (PKR2. The peripheral effect of prokineticin-2 on adipocytes/preadipocytes has not been studied yet. METHODOLOGY/PRINCIPAL FINDINGS: Since adipocytes and preadipocytes express mainly prokineticin receptor-1 (PKR1, here, we explored the role of PKR1 in adipose tissue expansion, generating PKR1-null (PKR1(-/- and adipocyte-specific (PKR1(ad-/- mutant mice, and using murine and human preadipocyte cell lines. Both PKR1(-/- and PKR1(ad-/- had excessive abdominal adipose tissue, but only PKR1(-/- mice showed severe obesity and diabetes-like syndrome. PKR1(ad-/- mice had increased proliferating preadipocytes and newly formed adipocyte levels, leading to expansion of adipose tissue. Using PKR1-knockdown in 3T3-L1 preadipocytes, we show that PKR1 directly inhibits preadipocyte proliferation and differentiation. These PKR1 cell autonomous actions appear targeted at preadipocyte cell cycle regulatory pathways, through reducing cyclin D, E, cdk2, c-Myc levels. CONCLUSIONS/SIGNIFICANCE: These results suggest PKR1 to be a crucial player in the preadipocyte proliferation and differentiation. Our data should facilitate studies of both the pathogenesis and therapy of obesity in humans.

  17. Parsing pyrogenic polycyclic aromatic hydrocarbons: forensic chemistry, receptor models, and source control policy.

    Science.gov (United States)

    O'Reilly, Kirk T; Pietari, Jaana; Boehm, Paul D

    2014-04-01

    A realistic understanding of contaminant sources is required to set appropriate control policy. Forensic chemical methods can be powerful tools in source characterization and identification, but they require a multiple-lines-of-evidence approach. Atmospheric receptor models, such as the US Environmental Protection Agency (USEPA)'s chemical mass balance (CMB), are increasingly being used to evaluate sources of pyrogenic polycyclic aromatic hydrocarbons (PAHs) in sediments. This paper describes the assumptions underlying receptor models and discusses challenges in complying with these assumptions in practice. Given the variability within, and the similarity among, pyrogenic PAH source types, model outputs are sensitive to specific inputs, and parsing among some source types may not be possible. Although still useful for identifying potential sources, the technical specialist applying these methods must describe both the results and their inherent uncertainties in a way that is understandable to nontechnical policy makers. The authors present an example case study concerning an investigation of a class of parking-lot sealers as a significant source of PAHs in urban sediment. Principal component analysis is used to evaluate published CMB model inputs and outputs. Targeted analyses of 2 areas where bans have been implemented are included. The results do not support the claim that parking-lot sealers are a significant source of PAHs in urban sediments. © 2013 SETAC.

  18. Double-Nanodomain Coupling of Calcium Channels, Ryanodine Receptors, and BK Channels Controls the Generation of Burst Firing.

    Science.gov (United States)

    Irie, Tomohiko; Trussell, Laurence O

    2017-11-15

    Action potentials clustered into high-frequency bursts play distinct roles in neural computations. However, little is known about ionic currents that control the duration and probability of these bursts. We found that, in cartwheel inhibitory interneurons of the dorsal cochlear nucleus, the likelihood of bursts and the interval between their spikelets were controlled by Ca 2+ acting across two nanodomains, one between plasma membrane P/Q Ca 2+ channels and endoplasmic reticulum (ER) ryanodine receptors and another between ryanodine receptors and large-conductance, voltage- and Ca 2+ -activated K + (BK) channels. Each spike triggered Ca 2+ -induced Ca 2+ release (CICR) from the ER immediately beneath somatic, but not axonal or dendritic, plasma membrane. Moreover, immunolabeling demonstrated close apposition of ryanodine receptors and BK channels. Double-nanodomain coupling between somatic plasma membrane and hypolemmal ER cisterns provides a unique mechanism for rapid control of action potentials on the millisecond timescale. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. SMRT repression of nuclear receptors controls the adipogenic set point and metabolic homeostasis

    NARCIS (Netherlands)

    Nofsinger, Russell R.; Li, Pingping; Hong, Suk-Hyun; Jonker, Johan W.; Barish, Grant D.; Ying, Hao; Cheng, Sheue-Yann; LeBlanc, Mathias; Xu, Wei; Pei, Liming; Kang, Yeon-Joo; Nelson, Michael; Downes, Michael; Yu, Ruth T.; Olefsky, Jerrold M.; Lee, Chih-Hao; Evans, Ronald M.

    2008-01-01

    The nuclear receptor corepressor, silencing mediator of retinoid and thyroid hormone receptors (SMRT), is recruited by a plethora of transcription factors to mediate lineage and signal-dependent transcriptional repression. We generated a knockin mutation in the receptor interaction domain (RID) of

  20. The insect ecdysone receptor is a good potential target for RNAi-based pest control.

    Science.gov (United States)

    Yu, Rong; Xu, Xinping; Liang, Yongkang; Tian, Honggang; Pan, Zhanqing; Jin, Shouheng; Wang, Na; Zhang, Wenqing

    2014-01-01

    RNA interference (RNAi) has great potential for use in insect pest control. However, some significant challenges must be overcome before RNAi-based pest control can become a reality. One challenge is the proper selection of a good target gene for RNAi. Here, we report that the insect ecdysone receptor (EcR) is a good potential target for RNAi-based pest control in the brown planthopper Nilaparvata lugens, a serious insect pest of rice plants. We demonstrated that the use of a 360 bp fragment (NlEcR-c) that is common between NlEcR-A and NlEcR-B for feeding RNAi experiments significantly decreased the relative mRNA expression levels of NlEcR compared with those in the dsGFP control. Feeding RNAi also resulted in a significant reduction in the number of offspring per pair of N. lugens. Consequently, a transgenic rice line expressing NlEcR dsRNA was constructed by Agrobacterium- mediated transformation. The results of qRT-PCR showed that the total copy number of the target gene in all transgenic rice lines was 2. Northern blot analysis showed that the small RNA of the hairpin dsNlEcR-c was successfully expressed in the transgenic rice lines. After newly hatched nymphs of N. lugens fed on the transgenic rice lines, effective RNAi was observed. The NlEcR expression levels in all lines examined were decreased significantly compared with the control. In all lines, the survival rate of the nymphs was nearly 90%, and the average number of offspring per pair in the treated groups was significantly less than that observed in the control, with a decrease of 44.18-66.27%. These findings support an RNAi-based pest control strategy and are also important for the management of rice insect pests.

  1. Vascular Endothelial Growth Factor Receptor 3 Controls Neural Stem Cell Activation in Mice and Humans

    Directory of Open Access Journals (Sweden)

    Jinah Han

    2015-02-01

    Full Text Available Neural stem cells (NSCs continuously produce new neurons within the adult mammalian hippocampus. NSCs are typically quiescent but activated to self-renew or differentiate into neural progenitor cells. The molecular mechanisms of NSC activation remain poorly understood. Here, we show that adult hippocampal NSCs express vascular endothelial growth factor receptor (VEGFR 3 and its ligand VEGF-C, which activates quiescent NSCs to enter the cell cycle and generate progenitor cells. Hippocampal NSC activation and neurogenesis are impaired by conditional deletion of Vegfr3 in NSCs. Functionally, this is associated with compromised NSC activation in response to VEGF-C and physical activity. In NSCs derived from human embryonic stem cells (hESCs, VEGF-C/VEGFR3 mediates intracellular activation of AKT and ERK pathways that control cell fate and proliferation. These findings identify VEGF-C/VEGFR3 signaling as a specific regulator of NSC activation and neurogenesis in mammals.

  2. Pengaruh Campuran Ampas Tebu Dan Alang-Alang (Imperata Cylindrica) Sebagai Media Pertumbuhan Terhadap Kandungan Nutrisi Jamur Tiram Putih (Pleurotus Ostreatus)

    OpenAIRE

    Naila, Ishmatun; Purnomo, Adi Setyo

    2016-01-01

    Penelitian ini bertujuan untuk mengetahui pengaruh ampas tebu dan alang-alang (Imperata cylindrica) sebagai media pertumbuhan jamur tiram putih (Pleurotus ostreatus) terhadap kandungan nutrisinya. Ampas tebu dan alang-alang dipilih sebagai media pertumbuhan alternatif, karena tidak hanya mengandung lignoseluosa, tapi juga tersedia berlimpah di lingkungan. Variasi komposisi ampas tebu:alang-alang yang digunakan adalah 75:25 (A1); 50:50 (A2); 25:75 (A3); 0:100 (A4); dan 100:0 (A5). Pada penelit...

  3. Glyphosate and AMPA in U.S. streams, groundwater, precipitation and soils

    Science.gov (United States)

    Battaglin, William A.; Meyer, Michael T.; Kuivila, Kathryn; Dietze, Julie E.

    2014-01-01

    Herbicides containing glyphosate are used in more than 130 countries on more than 100 crops. In the United States (U.S.), agricultural use of glyphosate [N-(phosphonomethyl)glycine] has increased from less than 10,000 metric tons per year (active ingredient) in 1993 to more than 70,000 metric tons per year in 2006. In 2006, glyphosate accounted for about 20 percent of all herbicide use (by weight of active ingredient). Glyphosate formulations such as Roundup® are used in homes and in agriculture. Part of the reason for the popularity of glyphosate is the perception that it is an “environmentally benign” herbicide that has low toxicity and little mobility or persistence in the environment. The U.S. Geological Survey developed an analytical method using liquid chromatography/tandem mass spectrometry that can detect small amounts of glyphosate and its primary degradation product aminomethylphosphonic acid (AMPA) in water and sediment. Results from more than 2,000 samples collected from locations distributed across the U.S. indicate that glyphosate is more mobile and occurs more widely in the environment than was previously thought. Glyphosate and AMPA were detected (reporting limits between 0.1 and 0.02 micrograms per liter) in samples collected from surface water, groundwater, rainfall, soil water, and soil, at concentrations from less than 0.1 to more than 100 micrograms per liter. Glyphosate was detected more frequently in rain (86%), ditches and drains (71%), and soil (63%); and less frequently in groundwater (3%) and large rivers (18%). AMPA was detected more frequently in rain (86%), soil (82%), and large rivers (78%); and less frequently in groundwater (8%) and wetlands or vernal pools (37%). Most observed concentrations of glyphosate were well below levels of concern for humans or wildlife, and none exceeded the U.S. Environmental Protection Agency’s Maximum Contaminant Level of 700 micrograms per liter. However, the ecosystem effects of chronic low

  4. Development of calcium-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in cultured neocortical neurons visualized by cobalt staining

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1998-01-01

    The developmental expression of calcium (Ca2+)-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors in cultured neocortical neurons was evaluated by using cobalt uptake, a histochemical method that identifies cells expressing Ca2+-permeable, non-N-methyl-D-aspartate...

  5. Cell-specific cre recombinase expression allows selective ablation of glutamate receptors from mouse horizontal cells.

    Directory of Open Access Journals (Sweden)

    Sebastian Ströh

    Full Text Available In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57, a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99% and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl. In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼ 50% in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼ 75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less

  6. Cell-Specific Cre Recombinase Expression Allows Selective Ablation of Glutamate Receptors from Mouse Horizontal Cells

    Science.gov (United States)

    Janssen-Bienhold, Ulrike; Schultz, Konrad; Cimiotti, Kerstin; Weiler, Reto; Willecke, Klaus; Dedek, Karin

    2013-01-01

    In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57), a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99%) and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl). In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼50%) in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less excitatory input

  7. AmpaCity. Superconducting cables and fault current limiters for the energy supply in conurbations

    International Nuclear Information System (INIS)

    Merschel, F.; Noe, M.; Stemmle, M.; Hobl, A.; Sauerbach, O.

    2013-01-01

    In 2013 RWE Germany is working jointly with cable manufacturer Nexans and with the scientific support of the Karlsruhe Institute of Technology (KIT) to install world's longest superconducting cable in the downtown area electricity grid of Essen. The AmpaCity project is partly funded by the German Federal Ministry of Economics and Technology and is playing an exemplary role in the further development of electricity grids in major cities worldwide. The project consortium presents AmpaCity as a convincing system solution especially with respect to economics and security of supply. Components of the system are a superconducting three-phase AC cable with two terminations and one connection joint in combination with a fault current limiter, which is also based on superconducting materials. The superconducting system is designed for 10 kV nominal voltage and 40 MW nominal power. It will replace a 110 kV cable system of equal capacity. At the same time, the project partners are paving the way for high failsafe performance, as the cable in conjunction with the fault current limiter cannot be overloaded by short circuit currents in the event of faults in the grid. Planning and follow up on the civil works in Essen posed a major challenge. Cable laying in the inner city, with various crossings of major highways, tramways, as well as already dense cable routes necessitated very thorough preparation and coordination. The civil works in Essen started in April 2013. At around the same time, after the cable had passed the type test, it went into production. Cable laying is scheduled for late summer. After commissioning, planned for the end of 2013, the field trial will run for at least two years under real grid conditions, to demonstrate this technology's suitability for wider deployment.

  8. 3D.07: CORRELATION BETWEEN THE ARTERIAL PRESSURE VARIABILITY ESTIMATED AT CLINICS, MAPA AND AMPA.

    Science.gov (United States)

    Abellan-Huerta, J; García-Escribano, I A; Soto, R M; Leal, M; Torres, A; Guerrero, B; Melgar, A C; Soto, M; Soria, F; Abellan-Aleman, J

    2015-06-01

    To measure the variability (VB) of the arterial pressure (AP) with the use of serial measurements at the clinics (VBCLIN), with 24 h ambulatory monitoring (MAPA) (VBMAPA) and home automonitoring -AMPA- (VBAMPA) and to estimate a relationship among each method. This is an observational, descriptive and transversal study assessed with 91 hypertensive patients in treatment and stable with AP MAPA was assessed to all the patients included in the study in order to obtain the VBMAPA and an AMPA in two non-consecutive weeks to obtain the VBAMPA (total of 54 measurements). 91 patients with 66 ± 7.7 years old and 58.2% males were recruited. AP values were 134 ± 14/82 ± 10 mmHg for systolic and diastolic APCLIN, respectively. AP values were 122 ± 17 / 68 ± 12 mmHg for systolic and diastolic APMAPA, respectively. AP values were 125 ± 13/75 ± 7 mmHg for systolic and diastolic APAMPA, respectively. The systolic VB for the three above methods was significantly correlated being maximal between VBCLIN and VBAMPA (r = 0.45; 0 MAPA methods is weak. This observation suggests that these are not interchangeable methodologies. Future studies focused on the relationship between VB -with different methods- and vascular target organ damage would be of great help in order to define the best analytical method.

  9. Leptin receptor Gln223Arg polymorphism and breast cancer risk in Nigerian women: A case control study

    International Nuclear Information System (INIS)

    Okobia, Michael N; Taioli, Emanuela; Bunker, Clareann H; Garte, Seymour J; Zmuda, Joseph M; Ezeome, Emmanuel R; Anyanwu, Stanley N; Uche, Emmanuel E; Kuller, Lewis H; Ferrell, Robert E

    2008-01-01

    Leptin, a 16 kDa polypeptide hormone, implicated in various physiological processes, exerts its action through the leptin receptor, a member of the class I cytokine receptor family. Both leptin and leptin receptor have recently been implicated in processes leading to breast cancer initiation and progression in animal models and humans. An A to G transition mutation in codon 223 in exon 6 of the leptin receptor gene, resulting in glutamine to arginine substitution (Gln223Arg), lies within the first of two putative leptin-binding regions and may be associated with impaired signaling capacity of the leptin receptor. This study was designed to assess the role of this polymorphism in breast cancer susceptibility in Nigerian women. We utilized a polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) assay to evaluate the association between the Gln223Arg polymorphism of the leptin receptor gene and breast risk in Nigeria in a case control study involving 209 women with breast cancer and 209 controls without the disease. Study participants were recruited from surgical outpatient clinics and surgical wards of four University Teaching Hospitals located in Midwestern and southeastern Nigeria between September 2002 and April 2004. Premenopausal women carrying at least one LEPR 223Arg allele were at a modestly increased risk of breast cancer after adjusting for confounders (OR = 1.8, 95% confidence interval [CI] 1.0–3.2, p = 0.07). There was no association with postmenopausal breast cancer risk (OR = 0.9, 95% CI 0.4–1.8, p = 0.68). Our results suggest that the LEPR Gln223Arg polymorphism in the extracellular domain of the LEPR receptor gene is associated with a modestly increased risk of premenopausal breast cancer in Nigerian women

  10. Vitamin D receptor-mediated control of Soggy, Wise, and Hairless gene expression in keratinocytes.

    Science.gov (United States)

    Hsieh, Jui-Cheng; Estess, Rudolf C; Kaneko, Ichiro; Whitfield, G Kerr; Jurutka, Peter W; Haussler, Mark R

    2014-02-01

    The vitamin D receptor (VDR), but not its hormonal ligand, 1,25-dihydroxyvitamin D3 (1,25D), is required for the progression of the mammalian hair cycle. We studied three genes relevant to hair cycle signaling, DKKL1 (Soggy), SOSTDC1 (Wise), and HR (Hairless), to determine whether their expression is regulated by VDR and/or its 1,25D ligand. DKKL1 mRNA was repressed 49-72% by 1,25D in primary human and CCD-1106 KERTr keratinocytes; a functional vitamin D responsive element (VDRE) was identified at -9590 bp in murine Soggy. Similarly, SOSTDC1 mRNA was repressed 41-59% by 1,25D in KERTr and primary human keratinocytes; a functional VDRE was located at -6215 bp in human Wise. In contrast, HR mRNA was upregulated 1.56- to 2.77-fold by 1,25D in primary human and KERTr keratinocytes; a VDRE (TGGTGAgtgAGGACA) consisting of an imperfect direct repeat separated by three nucleotides (DR3) was identified at -7269 bp in the human Hairless gene that mediated dramatic induction, even in the absence of 1,25D ligand. In parallel, a DR4 thyroid hormone responsive element, TGGTGAggccAGGACA, was identified at +1304 bp in the human HR gene that conferred tri-iodothyronine (T3)-independent transcriptional activation. Because the thyroid hormone receptor controls HR expression in the CNS, whereas VDR functions in concert with the HR corepressor specifically in skin, a model is proposed wherein unliganded VDR upregulates the expression of HR, the gene product of which acts as a downstream comodulator to feedback-repress DKKL1 and SOSTDC1, resulting in integration of bone morphogenic protein and Wnt signaling to drive the mammalian hair cycle and/or influencing epidermal function.

  11. Spatial glyphosate and AMPA redistribution on the soil surface driven by sediment transport processes - A flume experiment.

    Science.gov (United States)

    Bento, Célia P M; Commelin, Meindert C; Baartman, Jantiene E M; Yang, Xiaomei; Peters, Piet; Mol, Hans G J; Ritsema, Coen J; Geissen, Violette

    2018-03-01

    This study investigates the influence of small-scale sediment transport on glyphosate and AMPA redistribution on the soil surface and on their off-site transport during water erosion events. Both a smooth surface (T1) and a surface with "seeding lines on the contour" (T2) were tested in a rainfall simulation experiment using soil flumes (1 × 0.5 m) with a 5% slope. A dose of 178 mg m -2 of a glyphosate-based formulation (CLINIC ® ) was applied on the upper 0.2 m of the flumes. Four 15-min rainfall events (RE) with 30-min interval in between and a total rainfall intensity of 30 mm h -1 were applied. Runoff samples were collected after each RE in a collector at the flume outlet. At the end of the four REs, soil and sediment samples were collected in the application area and in four 20 cm-segments downslope of the application area. Samples were collected according to the following visually distinguished soil surface groups: light sedimentation (LS), dark sedimentation (DS), background and aggregates. Results showed that runoff, suspended sediment and associated glyphosate and AMPA off-site transport were significantly lower in T2 than in T1. Glyphosate and AMPA off-site deposition was higher for T2 than for T1, and their contents on the soil surface decreased with increasing distance from the application area for all soil surface groups and in both treatments. The LS and DS groups presented the highest glyphosate and AMPA contents, but the background group contributed the most to the downslope off-site deposition. Glyphosate and AMPA off-target particle-bound transport was 9.4% (T1) and 17.8% (T2) of the applied amount, while water-dissolved transport was 2.8% (T1) and 0.5% (T2). Particle size and organic matter influenced the mobility of glyphosate and AMPA to off-target areas. These results indicate that the pollution risk of terrestrial and aquatic environments through runoff and deposition can be considerable. Copyright © 2017 Elsevier Ltd

  12. Vascular Type 1A Angiotensin II Receptors Control BP by Regulating Renal Blood Flow and Urinary Sodium Excretion.

    Science.gov (United States)

    Sparks, Matthew A; Stegbauer, Johannes; Chen, Daian; Gomez, Jose A; Griffiths, Robert C; Azad, Hooman A; Herrera, Marcela; Gurley, Susan B; Coffman, Thomas M

    2015-12-01

    Inappropriate activation of the type 1A angiotensin (AT1A) receptor contributes to the pathogenesis of hypertension and its associated complications. To define the role for actions of vascular AT1A receptors in BP regulation and hypertension pathogenesis, we generated mice with cell-specific deletion of AT1A receptors in smooth muscle cells (SMKO mice) using Loxp technology and Cre transgenes with robust expression in both conductance and resistance arteries. We found that elimination of AT1A receptors from vascular smooth muscle cells (VSMCs) caused a modest (approximately 7 mmHg) yet significant reduction in baseline BP and exaggerated sodium sensitivity in mice. Additionally, the severity of angiotensin II (Ang II)-dependent hypertension was dramatically attenuated in SMKO mice, and this protection against hypertension was associated with enhanced urinary excretion of sodium. Despite the lower BP, acute vasoconstrictor responses to Ang II in the systemic vasculature were largely preserved (approximately 80% of control levels) in SMKO mice because of exaggerated activity of the sympathetic nervous system rather than residual actions of AT1B receptors. In contrast, Ang II-dependent responses in the renal circulation were almost completely eliminated in SMKO mice (approximately 5%-10% of control levels). These findings suggest that direct actions of AT1A receptors in VSMCs are essential for regulation of renal blood flow by Ang II and highlight the capacity of Ang II-dependent vascular responses in the kidney to effect natriuresis and BP control. Copyright © 2015 by the American Society of Nephrology.

  13. [Studying specific effects of nootropic drugs on glutamate receptors in the rat brain].

    Science.gov (United States)

    Firstova, Iu Iu; Vasil'eva, E V; Kovalev, G I

    2011-01-01

    The influence of nootropic drugs of different groups (piracetam, phenotropil, nooglutil, noopept, semax, meclofenoxate, pantocalcine, and dimebon) on the binding of the corresponding ligands to AMPA, NMDA, and mGlu receptors of rat brain has been studied by the method of radio-ligand binding in vitro. It is established that nooglutil exhibits pharmacologically significant competition with a selective agonist of AMPA receptors ([G-3H]Ro 48-8587) for the receptor binding sites (with IC50 = 6.4 +/- 0.2 microM), while the competition of noopept for these receptor binding sites was lower by an order of magnitude (IC50 = 80 +/- 5.6 microM). The heptapeptide drug semax was moderately competitive with [G-3H]LY 354740 for mGlu receptor sites (IC50 = 33 +/- 2.4 microM). Dimebon moderately influenced the specific binding of the ligand of NMDA receptor channel ([G-3H]MK-801) at IC50 = 59 +/- 3.6 microM. Nootropic drugs of the pyrrolidone group (piracetam, phenotropil) as well as meclofenoxate, pantocalcine (pantogam) in a broad rage of concentrations (10(-4)-10(-10) M) did not affect the binding of the corresponding ligands to glutamate receptors (IC50 100 pM). Thus, the direct neurochemical investigation was used for the first time to qualitatively characterize the specific binding sites for nooglutil and (to a lower extent) noopept on AMPA receptors, for semax on metabotropic glutamate receptors, and for dimebon on the channel region of NMDA receptors. The results are indicative of a selective action of some nootropes on the glutamate family.

  14. Human Immunodeficiency Virus Type-1 Elite Controllers Maintain Low Co-Expression of Inhibitory Receptors on CD4+ T Cells.

    Science.gov (United States)

    Noyan, Kajsa; Nguyen, Son; Betts, Michael R; Sönnerborg, Anders; Buggert, Marcus

    2018-01-01

    Human immunodeficiency virus type-1 (HIV-1) elite controllers (ELCs) represent a unique population that control viral replication in the absence of antiretroviral therapy (cART). It is well established that expression of multiple inhibitory receptors on CD8+ T cells is associated with HIV-1 disease progression. However, whether reduced co-expression of inhibitory receptors on CD4+ T cells is linked to natural viral control and slow HIV-1 disease progression remains undefined. Here, we report on the expression pattern of numerous measurable inhibitory receptors, associated with T cell exhaustion (programmed cell death-1, CTLA-4, and TIGIT), on different CD4+ T cell memory populations in ELCs and HIV-infected subjects with or without long-term cART. We found that the co-expression pattern of inhibitory receptors was significantly reduced in ELCs compared with HIV-1 cART-treated and viremic subjects, and similar to healthy controls. Markers associated with T cell exhaustion varied among different memory CD4+ T cell subsets and highest levels were found mainly on transitional memory T cells. CD4+ T cells co-expressing all inhibitory markers were positively correlated to T cell activation (CD38+ HLA-DR+) as well as the transcription factors Helios and FoxP3. Finally, clinical parameters such as CD4 count, HIV-1 viral load, and the CD4/CD8 ratio all showed significant associations with CD4+ T cell exhaustion. We demonstrate that ELCs are able to maintain lower levels of CD4+ T cell exhaustion despite years of ongoing viral replication compared with successfully cART-treated subjects. Our findings suggest that ELCs harbor a "healthy" state of inhibitory receptor expression on CD4+ T cells that might play part in maintenance of their control status.

  15. Activity-dependent control of NMDA receptor subunit composition at hippocampal mossy fibre synapses.

    Science.gov (United States)

    Carta, Mario; Srikumar, Bettadapura N; Gorlewicz, Adam; Rebola, Nelson; Mulle, Christophe

    2018-02-15

    CA3 pyramidal cells display input-specific differences in the subunit composition of synaptic NMDA receptors (NMDARs). Although at low density, GluN2B contributes significantly to NMDAR-mediated EPSCs at mossy fibre synapses. Long-term potentiation (LTP) of NMDARs triggers a modification in the subunit composition of synaptic NMDARs by insertion of GluN2B. GluN2B subunits are essential for the expression of LTP of NMDARs at mossy fibre synapses. Single neurons express NMDA receptors (NMDARs) with distinct subunit composition and biophysical properties that can be segregated in an input-specific manner. The dynamic control of the heterogeneous distribution of synaptic NMDARs is crucial to control input-dependent synaptic integration and plasticity. In hippocampal CA3 pyramidal cells from mice of both sexes, we found that mossy fibre (MF) synapses display a markedly lower proportion of GluN2B-containing NMDARs than associative/commissural synapses. The mechanism involved in such heterogeneous distribution of GluN2B subunits is not known. Here we show that long-term potentiation (LTP) of NMDARs, which is selectively expressed at MF-CA3 pyramidal cell synapses, triggers a modification in the subunit composition of synaptic NMDARs by insertion of GluN2B. This activity-dependent recruitment of GluN2B at mature MF-CA3 pyramidal cell synapses contrasts with the removal of GluN2B subunits at other glutamatergic synapses during development and in response to activity. Furthermore, although expressed at low levels, GluN2B is necessary for the expression of LTP of NMDARs at MF-CA3 pyramidal cell synapses. Altogether, we reveal a previously unknown activity-dependent regulation and function of GluN2B subunits that may contribute to the heterogeneous plasticity induction rules in CA3 pyramidal cells. © 2017 Centre Nationnal de la Recherche Scientifique. The Journal of Physiology © 2017 The Physiological Society.

  16. Enhanced inhibitory control by neuropeptide Y Y5 receptor blockade in rats.

    Science.gov (United States)

    Bari, A; Dec, A; Lee, A W; Lee, J; Song, D; Dale, E; Peterson, J; Zorn, S; Huang, X; Campbell, B; Robbins, T W; West, A R

    2015-03-01

    The neuropeptide Y (NPY) system acts in synergy with the classic neurotransmitters to regulate a large variety of functions including autonomic, affective, and cognitive processes. Research on the effects of NPY in the central nervous system has focused on food intake control and affective processes, but growing evidence of NPY involvement in attention-deficit/hyperactivity disorder (ADHD) and other psychiatric conditions motivated the present study. We tested the effects of the novel and highly selective NPY Y5 receptor antagonist Lu AE00654 on impulsivity and the underlying cortico-striatal circuitry in rats to further explore the possible involvement of the NPY system in pathologies characterized by inattention and impulsive behavior. A low dose of Lu AE00654 (0.03 mg/kg) selectively facilitated response inhibition as measured by the stop-signal task, whereas no effects were found at higher doses (0.3 and 3 mg/kg). Systemic administration of Lu AE00654 also enhanced the inhibitory influence of the dorsal frontal cortex on neurons in the caudate-putamen, this fronto-striatal circuitry being implicated in the executive control of behavior. Finally, by locally injecting a Y5 agonist, we observed reciprocal activation between dorsal frontal cortex and caudate-putamen neurons. Importantly, the effects of the Y5 agonist were attenuated by pretreatment with Lu AE00654, confirming the presence of Y5 binding sites modulating functional interactions within frontal-subcortical circuits. These results suggest that the NPY system modulates inhibitory neurotransmission in brain areas important for impulse control, and may be relevant for the treatment of pathologies such as ADHD and drug abuse.

  17. The receptor kinase FER is a RALF-regulated scaffold controlling plant immune signaling

    NARCIS (Netherlands)

    Stegmann, Martin; Monaghan, Jacqueline; Smakowska-Luzan, Elwira; Rovenich, Hanna; Lehner, Anita; Holton, Nicholas; Belkhadir, Youssef; Zipfel, Cyril

    2017-01-01

    In plants, perception of invading pathogens involves cell-surface immune receptor kinases. Here, we report that the Arabidopsis SITE-1 PROTEASE (S1P) cleaves endogenous RAPID ALKALINIZATION FACTOR (RALF) propeptides to inhibit plant immunity. This inhibition is mediated by the malectin-like receptor

  18. Confinement of activating receptors at the plasma membrane controls natural killer cell tolerance.

    Science.gov (United States)

    Guia, Sophie; Jaeger, Baptiste N; Piatek, Stefan; Mailfert, Sébastien; Trombik, Tomasz; Fenis, Aurore; Chevrier, Nicolas; Walzer, Thierry; Kerdiles, Yann M; Marguet, Didier; Vivier, Eric; Ugolini, Sophie

    2011-04-05

    Natural killer (NK) cell tolerance to self is partly ensured by major histocompatibility complex (MHC) class I-specific inhibitory receptors on NK cells, which dampen their reactivity when engaged. However, NK cells that do not detect self MHC class I are not autoreactive. We used dynamic fluorescence correlation spectroscopy to show that MHC class I-independent NK cell tolerance in mice was associated with the presence of hyporesponsive NK cells in which both activating and inhibitory receptors were confined in an actin meshwork at the plasma membrane. In contrast, the recognition of self MHC class I by inhibitory receptors "educated" NK cells to become fully reactive, and activating NK cell receptors became dynamically compartmentalized in membrane nanodomains. We propose that the confinement of activating receptors at the plasma membrane is pivotal to ensuring the self-tolerance of NK cells.

  19. Brain IGF-1 receptors control mammalian growth and lifespan through a neuroendocrine mechanism.

    Directory of Open Access Journals (Sweden)

    Laurent Kappeler

    2008-10-01

    Full Text Available Mutations that decrease insulin-like growth factor (IGF and growth hormone signaling limit body size and prolong lifespan in mice. In vertebrates, these somatotropic hormones are controlled by the neuroendocrine brain. Hormone-like regulations discovered in nematodes and flies suggest that IGF signals in the nervous system can determine lifespan, but it is unknown whether this applies to higher organisms. Using conditional mutagenesis in the mouse, we show that brain IGF receptors (IGF-1R efficiently regulate somatotropic development. Partial inactivation of IGF-1R in the embryonic brain selectively inhibited GH and IGF-I pathways after birth. This caused growth retardation, smaller adult size, and metabolic alterations, and led to delayed mortality and longer mean lifespan. Thus, early changes in neuroendocrine development can durably modify the life trajectory in mammals. The underlying mechanism appears to be an adaptive plasticity of somatotropic functions allowing individuals to decelerate growth and preserve resources, and thereby improve fitness in challenging environments. Our results also suggest that tonic somatotropic signaling entails the risk of shortened lifespan.

  20. Inflammation alters AMPA-stimulated calcium responses in dorsal striatal D2 but not D1 spiny projection neurons.

    Science.gov (United States)

    Winland, Carissa D; Welsh, Nora; Sepulveda-Rodriguez, Alberto; Vicini, Stefano; Maguire-Zeiss, Kathleen A

    2017-11-01

    Neuroinflammation precedes neuronal loss in striatal neurodegenerative diseases and can be exacerbated by the release of proinflammatory molecules by microglia. These molecules can affect trafficking of AMPARs. The preferential trafficking of calcium-permeable versus impermeable AMPARs can result in disruptions of [Ca 2+ ] i and alter cellular functions. In striatal neurodegenerative diseases, changes in [Ca 2+ ] i and L-type voltage-gated calcium channels (VGCCs) have been reported. Therefore, this study sought to determine whether a proinflammatory environment alters AMPA-stimulated [Ca 2+ ] i through calcium-permeable AMPARs and/or L-type VGCCs in dopamine-2- and dopamine-1-expressing striatal spiny projection neurons (D2 and D1 SPNs) in the dorsal striatum. Mice expressing the calcium indicator protein, GCaMP in D2 or D1 SPNs, were utilized for calcium imaging. Microglial activation was assessed by morphology analyses. To induce inflammation, acute mouse striatal slices were incubated with lipopolysaccharide (LPS). Here we report that LPS treatment potentiated AMPA responses only in D2 SPNs. When a nonspecific VGCC blocker was included, we observed a decrease of AMPA-stimulated calcium fluorescence in D2 but not D1 SPNs. The remaining agonist-induced [Ca 2+ ] i was mediated by calcium-permeable AMPARs because the responses were completely blocked by a selective calcium-permeable AMPAR antagonist. We used isradipine, the highly selective L-type VGCC antagonist to determine the role of L-type VGCCs in SPNs treated with LPS. Isradipine decreased AMPA-stimulated responses selectively in D2 SPNs after LPS treatment. Our findings suggest that dorsal striatal D2 SPNs are specifically targeted in proinflammatory conditions and that L-type VGCCs and calcium-permeable AMPARs are important mediators of this effect. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  1. Parvovirus Capsid Structures Required for Infection: Mutations Controlling Receptor Recognition and Protease Cleavages.

    Science.gov (United States)

    Callaway, Heather M; Feng, Kurtis H; Lee, Donald W; Allison, Andrew B; Pinard, Melissa; McKenna, Robert; Agbandje-McKenna, Mavis; Hafenstein, Susan; Parrish, Colin R

    2017-01-15

    Parvovirus capsids are small but complex molecular machines responsible for undertaking many of the steps of cell infection, genome packing, and cell-to-cell as well as host-to-host transfer. The details of parvovirus infection of cells are still not fully understood, but the processes must involve small changes in the capsid structure that allow the endocytosed virus to escape from the endosome, pass through the cell cytoplasm, and deliver the single-stranded DNA (ssDNA) genome to the nucleus, where viral replication occurs. Here, we examine capsid substitutions that eliminate canine parvovirus (CPV) infectivity and identify how those mutations changed the capsid structure or altered interactions with the infectious pathway. Amino acid substitutions on the exterior surface of the capsid (Gly299Lys/Ala300Lys) altered the binding of the capsid to transferrin receptor type 1 (TfR), particularly during virus dissociation from the receptor, but still allowed efficient entry into both feline and canine cells without successful infection. These substitutions likely control specific capsid structural changes resulting from TfR binding required for infection. A second set of changes on the interior surface of the capsid reduced viral infectivity by >100-fold and included two cysteine residues and neighboring residues. One of these substitutions, Cys270Ser, modulates a VP2 cleavage event found in ∼10% of the capsid proteins that also was shown to alter capsid stability. A neighboring substitution, Pro272Lys, significantly reduced capsid assembly, while a Cys273Ser change appeared to alter capsid transport from the nucleus. These mutants reveal additional structural details that explain cell infection processes of parvovirus capsids. Parvoviruses are commonly found in both vertebrate and invertebrate animals and cause widespread disease. They are also being developed as oncolytic therapeutics and as gene therapy vectors. Most functions involved in infection or transduction

  2. Parvovirus Capsid Structures Required for Infection: Mutations Controlling Receptor Recognition and Protease Cleavages

    Science.gov (United States)

    Callaway, Heather M.; Feng, Kurtis H.; Lee, Donald W.; Pinard, Melissa; McKenna, Robert; Agbandje-McKenna, Mavis; Hafenstein, Susan

    2016-01-01

    ABSTRACT Parvovirus capsids are small but complex molecular machines responsible for undertaking many of the steps of cell infection, genome packing, and cell-to-cell as well as host-to-host transfer. The details of parvovirus infection of cells are still not fully understood, but the processes must involve small changes in the capsid structure that allow the endocytosed virus to escape from the endosome, pass through the cell cytoplasm, and deliver the single-stranded DNA (ssDNA) genome to the nucleus, where viral replication occurs. Here, we examine capsid substitutions that eliminate canine parvovirus (CPV) infectivity and identify how those mutations changed the capsid structure or altered interactions with the infectious pathway. Amino acid substitutions on the exterior surface of the capsid (Gly299Lys/Ala300Lys) altered the binding of the capsid to transferrin receptor type 1 (TfR), particularly during virus dissociation from the receptor, but still allowed efficient entry into both feline and canine cells without successful infection. These substitutions likely control specific capsid structural changes resulting from TfR binding required for infection. A second set of changes on the interior surface of the capsid reduced viral infectivity by >100-fold and included two cysteine residues and neighboring residues. One of these substitutions, Cys270Ser, modulates a VP2 cleavage event found in ∼10% of the capsid proteins that also was shown to alter capsid stability. A neighboring substitution, Pro272Lys, significantly reduced capsid assembly, while a Cys273Ser change appeared to alter capsid transport from the nucleus. These mutants reveal additional structural details that explain cell infection processes of parvovirus capsids. IMPORTANCE Parvoviruses are commonly found in both vertebrate and invertebrate animals and cause widespread disease. They are also being developed as oncolytic therapeutics and as gene therapy vectors. Most functions involved in

  3. Peripheral and central CB1 cannabinoid receptors control stress-induced impairment of memory consolidation.

    Science.gov (United States)

    Busquets-Garcia, Arnau; Gomis-González, Maria; Srivastava, Raj Kamal; Cutando, Laura; Ortega-Alvaro, Antonio; Ruehle, Sabine; Remmers, Floortje; Bindila, Laura; Bellocchio, Luigi; Marsicano, Giovanni; Lutz, Beat; Maldonado, Rafael; Ozaita, Andrés

    2016-08-30

    Stressful events can generate emotional memories linked to the traumatic incident, but they also can impair the formation of nonemotional memories. Although the impact of stress on emotional memories is well studied, much less is known about the influence of the emotional state on the formation of nonemotional memories. We used the novel object-recognition task as a model of nonemotional memory in mice to investigate the underlying mechanism of the deleterious effect of stress on memory consolidation. Systemic, hippocampal, and peripheral blockade of cannabinoid type-1 (CB1) receptors abolished the stress-induced memory impairment. Genetic deletion and rescue of CB1 receptors in specific cell types revealed that the CB1 receptor population specifically in dopamine β-hydroxylase (DBH)-expressing cells is both necessary and sufficient for stress-induced impairment of memory consolidation, but CB1 receptors present in other neuronal populations are not involved. Strikingly, pharmacological manipulations in mice expressing CB1 receptors exclusively in DBH(+) cells revealed that both hippocampal and peripheral receptors mediate the impact of stress on memory consolidation. Thus, CB1 receptors on adrenergic and noradrenergic cells provide previously unrecognized cross-talk between central and peripheral mechanisms in the stress-dependent regulation of nonemotional memory consolidation, suggesting new potential avenues for the treatment of cognitive aspects on stress-related disorders.

  4. Mu opioid receptor availability in people with psychiatric disorders who died by suicide: a case control study.

    Science.gov (United States)

    Scarr, Elizabeth; Money, Tammie Terese; Pavey, Geoffrey; Neo, Jaclyn; Dean, Brian

    2012-08-28

    Mu opioid receptors have previously been shown to be altered in people with affective disorders who died as a result of suicide. We wished to determine whether these changes were more widespread and independent of psychiatric diagnoses. Mu receptor levels were determined using [3 H]DAMGO binding in BA24 from 51 control subjects; 38 people with schizophrenia (12 suicides); 20 people with major depressive disorder (15 suicides); 13 people with bipolar disorder (5 suicides) and 9 people who had no history of psychiatric disorders but who died as a result of suicide. Mu receptor levels were further determined in BA9 and caudate-putamen from 38 people with schizophrenia and 20 control subjects using [3 H]DAMGO binding and, in all three regions, using Western blots. Data was analysed using one-way ANOVAs with Bonferroni's Multiple Comparison Test or, where data either didn't approximate to a binomial distribution or the sample size was too small to determine distribution, a Kruskal-Wallis test with Dunn's Multiple Comparison Test. [3 H]DAMGO binding density was lower in people who had died as a result of suicide (pendogenous ligands occupying these receptors.

  5. Getting a Handle on Neuropharmacology by Targeting Receptor-Associated Proteins.

    Science.gov (United States)

    Maher, Michael P; Matta, Jose A; Gu, Shenyan; Seierstad, Mark; Bredt, David S

    2017-12-06

    Targeted therapy for neuropsychiatric disorders requires selective modulation of dysfunctional neuronal pathways. Receptors relevant to CNS disorders typically have associated proteins discretely expressed in specific neuronal pathways; these accessory proteins provide a new dimension for drug discovery. Recent studies show that targeting a TARP auxiliary subunit of AMPA receptors selectively modulates neuronal excitability in specific forebrain pathways relevant to epilepsy. Other medicinally important ion channels, gated by glutamate, γ-aminobutyric acid (GABA), and acetylcholine, also have associated proteins, which may be druggable. This emerging pharmacology of receptor-associated proteins provides a new approach for improving drug efficacy while mitigating side effects. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Hypothalamic growth hormone receptor (GHR controls hepatic glucose production in nutrient-sensing leptin receptor (LepRb expressing neurons

    Directory of Open Access Journals (Sweden)

    Gillian Cady

    2017-05-01

    Full Text Available Objective: The GH/IGF-1 axis has important roles in growth and metabolism. GH and GH receptor (GHR are active in the central nervous system (CNS and are crucial in regulating several aspects of metabolism. In the hypothalamus, there is a high abundance of GH-responsive cells, but the role of GH signaling in hypothalamic neurons is unknown. Previous work has demonstrated that the Ghr gene is highly expressed in LepRb neurons. Given that leptin is a key regulator of energy balance by acting on leptin receptor (LepRb-expressing neurons, we tested the hypothesis that LepRb neurons represent an important site for GHR signaling to control body homeostasis. Methods: To determine the importance of GHR signaling in LepRb neurons, we utilized Cre/loxP technology to ablate GHR expression in LepRb neurons (LeprEYFPΔGHR. The mice were generated by crossing the Leprcre on the cre-inducible ROSA26-EYFP mice to GHRL/L mice. Parameters of body composition and glucose homeostasis were evaluated. Results: Our results demonstrate that the sites with GHR and LepRb co-expression include ARH, DMH, and LHA neurons. Leptin action was not altered in LeprEYFPΔGHR mice; however, GH-induced pStat5-IR in LepRb neurons was significantly reduced in these mice. Serum IGF-1 and GH levels were unaltered, and we found no evidence that GHR signaling regulates food intake and body weight in LepRb neurons. In contrast, diminished GHR signaling in LepRb neurons impaired hepatic insulin sensitivity and peripheral lipid metabolism. This was paralleled with a failure to suppress expression of the gluconeogenic genes and impaired hepatic insulin signaling in LeprEYFPΔGHR mice. Conclusion: These findings suggest the existence of GHR-leptin neurocircuitry that plays an important role in the GHR-mediated regulation of glucose metabolism irrespective of feeding. Keywords: Growth hormone receptor, Hypothalamus, Leptin receptor, Glucose production, Liver

  7. Atypical Opioid Mechanisms of Control of Injury-Induced Cutaneous Pain by Delta Receptors

    Science.gov (United States)

    2016-07-01

    treat, and current opioids (i.e. mu opioid receptor agonists such as morphine) cause unacceptable side effects including addiction . Injuries suffered...treat, and current opioids that act on mu opioid receptors such as morphine generate significant side effects including addiction . War-related...al., J Neurosci Methods, 1994), starting with 0.1 g and ending with 2.0 g filament as cutoff value. As shown in Figure 2, our preliminary experiments

  8. Estrogen and progesterone receptor levels in nonneoplastic breast epithelium of breast cancer cases versus benign breast biopsy controls

    International Nuclear Information System (INIS)

    Woolcott, Christy G; SenGupta, Sandip K; Hanna, Wedad M; Aronson, Kristan J

    2008-01-01

    Previous studies and biological mechanisms of carcinogenesis suggest that the steroid receptor content of benign breast epithelium may be related to breast cancer risk. The objective in this study was to compare the levels of estrogen receptor-α (ER) and progesterone receptor (PR) in nonneoplastic breast epithelium between breast cancer cases and biopsy controls. Between 1995 and 1997 at two sites (Women's College Hospital in Toronto and Kingston General Hospital), 667 women who were scheduled for diagnostic excisional breast biopsies completed a questionnaire providing personal information and agreed to allow analysis of routinely resected tissue. Histological slides with nonneoplastic epithelium were available for 101 cancer cases and 200 biopsy controls in Toronto and for 105 cancer cases and 119 controls in Kingston. Nonneoplastic epithelium was examined with immunohistochemical assays to determine the percent of epithelial cells staining for ER and PR. Unconditional logistic regression was used to calculate odds ratios (OR) stratified by study site. The ER content of nonneoplastic tissue was higher in cases than biopsy controls in unadjusted analyses; after adjustment for age, however, a weak association remained in only one of the study sites. After adjustment for age, the PR content of nonneoplastic tissue was slightly lower in breast cancer cases than controls in one study site. Furthermore, this inverse association was confined to women with PR negative breast cancer in comparison to the controls. No interaction between ER and PR content of nonneoplastic tissue was observed in relation to the odds of having breast cancer. The results of this study are consistent with only a slight indication of increased ER levels in nonneoplastic tissue in breast cancer cases relative to controls. This study contributes to the understanding of breast cancer by examining both ER and PR in nonneoplastic tissue. Limitations remain, however, such as the necessity of

  9. Mu opioid receptor availability in people with psychiatric disorders who died by suicide: a case control study

    Directory of Open Access Journals (Sweden)

    Scarr Elizabeth

    2012-08-01

    Full Text Available Abstract Background Mu opioid receptors have previously been shown to be altered in people with affective disorders who died as a result of suicide. We wished to determine whether these changes were more widespread and independent of psychiatric diagnoses. Methods Mu receptor levels were determined using [3 H]DAMGO binding in BA24 from 51 control subjects; 38 people with schizophrenia (12 suicides; 20 people with major depressive disorder (15 suicides; 13 people with bipolar disorder (5 suicides and 9 people who had no history of psychiatric disorders but who died as a result of suicide. Mu receptor levels were further determined in BA9 and caudate-putamen from 38 people with schizophrenia and 20 control subjects using [3 H]DAMGO binding and, in all three regions, using Western blots. Data was analysed using one-way ANOVAs with Bonferroni’s Multiple Comparison Test or, where data either didn’t approximate to a binomial distribution or the sample size was too small to determine distribution, a Kruskal-Wallis test with Dunn’s Multiple Comparison Test. Results [3 H]DAMGO binding density was lower in people who had died as a result of suicide (p3 H]DAMGO binding densities, but not mu protein levels, were significantly decreased in BA9 from people with schizophrenia who died as a result of suicide (p Conclusions Overall these data suggest that mu opioid receptor availability is decreased in the brains of people with schizophrenia who died as a result of suicide, which would be consistent with increased levels of endogenous ligands occupying these receptors.

  10. HIV-1, HTLV-I and the interleukin-2 receptor: insights into transcriptional control.

    Science.gov (United States)

    Böhnlein, E; Lowenthal, J W; Wano, Y; Franza, B R; Ballard, D W; Greene, W C

    1989-01-01

    In this study, we present direct evidence for the binding of the inducible cellular protein, HIVEN86A, to a 12-bp element present in the IL-2R alpha promoter. This element shares significant sequence similarity with the NF-kappa B binding sites present in the HIV-1 and kappa immunoglobulin enhancers. Transient transfection studies indicate that this kappa B element is both necessary and sufficient to confer tax or mitogen inducibility to a heterologous promoter. As summarized schematically in Fig. 5, the findings suggest that the HIVEN86A protein may play a central role in the activation of cellular genes required for T-cell growth, specifically the IL-2R alpha gene. In addition, the induced HIVEN86A protein also binds to a similar sequence present in the HIV-1 LTR leading to enhanced viral gene expression and ultimately T-cell death. Thus, mitogen activation of the HIV-1 LTR appears to involve the same inducible transcription factor(s) that normally regulates IL-2R alpha gene expression and T-cell growth. These findings further underscore the importance of the state of T-cell activation in the regulation of HIV-1 replication. Our results also demonstrate that HIVEN86A is induced by the tax protein of HTLV-I. Thus, in HTLV-I infected cells, normally the tight control of the transient expression of the IL-2R alpha gene is lost. The constitutive high-level display of IL-2 receptors may play a role in leukemic transformation mediated by HTLV-I (ATL). Apparently by the same mechanism, the tax protein also activates the HIV-1 LTR through the induction of HIVEN86A.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Floral organ abscission peptide IDA and its HAE/HSL2 receptors control cell separation during lateral root emergence

    OpenAIRE

    Kumpf, Robert P.; Shi, Chun-Lin; Larrieu, Antoine; Stø, Ida Myhrer; Butenko, Melinka A.; Péret, Benjamin; Riiser, Even Sannes; Bennett, Malcolm J.; Aalen, Reidunn B.

    2013-01-01

    Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LI...

  12. Identification and expression of the CCAP receptor in the Chagas' disease vector, Rhodnius prolixus, and its involvement in cardiac control.

    Directory of Open Access Journals (Sweden)

    Dohee Lee

    Full Text Available Rhodnius prolixus is the vector of Chagas' disease, by virtue of transmitting the parasite Trypanosoma cruzi. There is no cure for Chagas' disease and therefore controlling R. prolixus is currently the only method of prevention. Understanding the physiology of the disease vector is an important step in developing control measures. Crustacean cardioactive peptide (CCAP is an important neuropeptide in insects because it has multiple physiological roles such as controlling heart rate and modulating ecdysis behaviour. In this study, we have cloned the cDNA sequence of the CCAP receptor (RhoprCCAPR from 5(th instar R. prolixus and found it to be a G-protein coupled receptor (GPCR. The spatial expression pattern in 5(th instars reveals that the RhoprCCAPR transcript levels are high in the central nervous system, hindgut and female reproductive systems, and lower in the salivary glands, male reproductive tissues and a pool of tissues including the dorsal vessel, trachea, and fat body. Interestingly, the RhoprCCAPR expression is increased prior to ecdysis and decreased post-ecdysis. A functional receptor expression assay confirms that the RhoprCCAPR is activated by CCAP (EC50 = 12 nM but not by adipokinetic hormone, corazonin or an extended FMRFamide. The involvement of CCAP in controlling heartbeat frequency was studied in vivo and in vitro by utilizing RNA interference. In vivo, the basal heartbeat frequency is decreased by 31% in bugs treated with dsCCAPR. Knocking down the receptor in dsCCAPR-treated bugs also resulted in loss of function of applied CCAP in vitro. This is the first report of a GPCR knock-down in R. prolixus and the first report showing that a reduction in CCAPR transcript levels leads to a reduction in cardiac output in any insect.

  13. KOMPROMI DAN INTERSEKSIONALITAS GENDER DALAM PEMBERIAN MAHAR: TRADISI AMPA COI NDAI PADA SUKU MBOJO

    Directory of Open Access Journals (Sweden)

    Atun Wardatun

    2009-06-01

    Full Text Available Ampa Co’i Ndai is a practiced tradition among Suku Mbojo[1] (Bimanese ethnic where the resource of bride-payment is from the brides, wholly or partially, but it is named after the groom during the declaration of marriage contract. The tradition is, usually, applicable if the social, economic, and/or educational status of brides are higher than that of grooms. Whereas, the ideal expectation of culture and religious norms position men as superior human beings. Gender analysis observes that the tradition is a compromise of the ideal expectation and the real fact of gender relation. In the gender intersectionality’s view, the tradition shows that the male-female relationship should not only be explained merely based on the sexual differences but should be examined comprehensively along with other social categories such as economic, social and educational status. Gender status should be seen as a cross-cutting issue which is inseparable with multi identities of human being. [1]Suku Mbojo adalah nama Suku bagi orang Bima (penduduk bagian paling Timur Nusatenggara Barat dan terletak di pulau Sumbawa.

  14. Changes in Angiotensin Receptor Distribution and in Aortic Morphology Are Associated with Blood Pressure Control in Aged Metabolic Syndrome Rats

    Directory of Open Access Journals (Sweden)

    Verónica Guarner-Lans

    2016-01-01

    Full Text Available The role of the renin-angiotensin system (RAS in blood pressure regulation in MS during aging is unknown. It participates in metabolic syndrome (MS and aging regulating vascular tone and remodeling. RAS might participate in a compensatory mechanism decreasing blood pressure and allowing MS rats to reach 18 months of age and it might form part of therapeutical procedures to ameliorate MS. We studied histological changes and distribution of RAS receptors in aortas of MS aged rats. Electron microscopy images showed premature aging in MS since the increased fibrosis, enlarged endothelium, and invasion of this layer by muscle cells that was present in control 18-month-old aortas were also found in 6-month-old aortas from MS rats. AT1, AT2, and Mas receptors mediate the effects of Ang II and Ang 1-7, respectively. Fluorescence from AT2 decreased with age in control and MS aortas, while fluorescence of AT1 increased in aortas from MS rats at 6 months and diminished during aging. Mas expression increased in MS rats and remained unchanged in control rats. In conclusion, there is premature aging in the aortas from MS rats and the elevated expression of Mas receptor might contribute to decrease blood pressure during aging in MS.

  15. Orphan Nuclear Receptor ERRα Controls Macrophage Metabolic Signaling and A20 Expression to Negatively Regulate TLR-Induced Inflammation.

    Science.gov (United States)

    Yuk, Jae-Min; Kim, Tae Sung; Kim, Soo Yeon; Lee, Hye-Mi; Han, Jeongsu; Dufour, Catherine Rosa; Kim, Jin Kyung; Jin, Hyo Sun; Yang, Chul-Su; Park, Ki-Sun; Lee, Chul-Ho; Kim, Jin-Man; Kweon, Gi Ryang; Choi, Hueng-Sik; Vanacker, Jean-Marc; Moore, David D; Giguère, Vincent; Jo, Eun-Kyeong

    2015-07-21

    The orphan nuclear receptor estrogen-related receptor α (ERRα; NR3B1) is a key metabolic regulator, but its function in regulating inflammation remains largely unknown. Here, we demonstrate that ERRα negatively regulates Toll-like receptor (TLR)-induced inflammation by promoting Tnfaip3 transcription and fine-tuning of metabolic reprogramming in macrophages. ERRα-deficient (Esrra(-/-)) mice showed increased susceptibility to endotoxin-induced septic shock, leading to more severe pro-inflammatory responses than control mice. ERRα regulated macrophage inflammatory responses by directly binding the promoter region of Tnfaip3, a deubiquitinating enzyme in TLR signaling. In addition, Esrra(-/-) macrophages showed an increased glycolysis, but impaired mitochondrial respiratory function and biogenesis. Further, ERRα was required for the regulation of NF-κB signaling by controlling p65 acetylation via maintenance of NAD(+) levels and sirtuin 1 activation. These findings unravel a previously unappreciated role for ERRα as a negative regulator of TLR-induced inflammatory responses through inducing Tnfaip3 transcription and controlling the metabolic reprogramming. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Provision of a simplified methodology for determining estradiol and progesterone receptors in human breast tumours. Internal and external quality control

    International Nuclear Information System (INIS)

    Farinate, Z.

    1990-10-01

    A simplified assay for the detection of progesterone receptors (PR) in human breast tissue is described. Tissue storage is at -20 deg. C rather than -70 deg. C and a centrifugation speed of 20,000 rpm avoids requirement of an ultracentrifuge. Cytosol preparations obtained from homogenized oestradiol benzoate primed wistar rat uteri performed satisfactorily as positive controls with stability of two months in liquid nitrogen. The use of iodinated tracer (progesterone 11 alpha glucuronide 125 I iodotyramine) proved disappointing in the progesterone receptor assay in contrast to 125 I oestradiol which worked well in a oestrogen receptor assay, previously developed. Hydroxyl-apatite was a better separating agent than dextran coated charcoal in both assays and yielded better sensitivity, particularly when protein concentrations were low. Five breast cancer specimens assayed yielded, by Scatchard analysis, Kd values between 12 to 22x10 -9 m|h, comparable to the positive controls. However, two of these had binding site capacity of less than 5 fmol/mg cytosol as compared to the three others and the positive controls where values ranged from 47-196 fmol/mg cytosol. 28 refs, 6 figs, 14 tabs

  17. Residues remote from the binding pocket control the antagonist selectivity towards the corticotropin-releasing factor receptor-1

    Science.gov (United States)

    Sun, Xianqiang; Cheng, Jianxin; Wang, Xu; Tang, Yun; Ågren, Hans; Tu, Yaoquan

    2015-01-01

    The corticotropin releasing factors receptor-1 and receptor-2 (CRF1R and CRF2R) are therapeutic targets for treating neurological diseases. Antagonists targeting CRF1R have been developed for the potential treatment of anxiety disorders and alcohol addiction. It has been found that antagonists targeting CRF1R always show high selectivity, although CRF1R and CRF2R share a very high rate of sequence identity. This has inspired us to study the origin of the selectivity of the antagonists. We have therefore built a homology model for CRF2R and carried out unbiased molecular dynamics and well-tempered metadynamics simulations for systems with the antagonist CP-376395 in CRF1R or CRF2R to address this issue. We found that the side chain of Tyr6.63 forms a hydrogen bond with the residue remote from the binding pocket, which allows Tyr6.63 to adopt different conformations in the two receptors and results in the presence or absence of a bottleneck controlling the antagonist binding to or dissociation from the receptors. The rotameric switch of the side chain of Tyr3566.63 allows the breaking down of the bottleneck and is a perquisite for the dissociation of CP-376395 from CRF1R.

  18. Purinergic control of inflammation and thrombosis: Role of P2X1 receptors

    Directory of Open Access Journals (Sweden)

    Cécile Oury

    2015-01-01

    Full Text Available Inflammation shifts the hemostatic mechanisms in favor of thrombosis. Upon tissue damage or infection, a sudden increase of extracellular ATP occurs, that might contribute to the crosstalk between inflammation and thrombosis. On platelets, P2X1 receptors act to amplify platelet activation and aggregation induced by other platelet agonists. These receptors critically contribute to thrombus stability in small arteries. Besides platelets, studies by our group indicate that these receptors are expressed by neutrophils. They promote neutrophil chemotaxis, both in vitro and in vivo. In a laser-induced injury mouse model of thrombosis, it appears that neutrophils are required to initiate thrombus formation and coagulation activation on inflamed arteriolar endothelia. In this model, by using P2X1−/− mice, we recently showed that P2X1 receptors, expressed on platelets and neutrophils, play a key role in thrombus growth and fibrin generation. Intriguingly, in a model of endotoxemia, P2X1−/− mice exhibited aggravated oxidative tissue damage, along with exacerbated thrombocytopenia and increased activation of coagulation, which translated into higher susceptibility to septic shock. Thus, besides its ability to recruit neutrophils and platelets on inflamed endothelia, the P2X1 receptor also contributes to limit the activation of circulating neutrophils under systemic inflammatory conditions. Taken together, these data suggest that P2X1 receptors are involved in the interplay between platelets, neutrophils and thrombosis. We propose that activation of these receptors by ATP on neutrophils and platelets represents a new mechanism that regulates thrombo-inflammation.

  19. Impaired virus control and severe CD8+ T-cell-mediated immunopathology in chimeric mice deficient in gamma interferon receptor expression on both parenchymal and hematopoietic cells

    DEFF Research Database (Denmark)

    Henrichsen, Pernille; Bartholdy, Christina; Christensen, Jan Pravsgaard

    2005-01-01

    be capable of responding to IFN-gamma, but expression of the relevant receptor on non-T cells could be experimentally controlled. Only when the IFN-gamma receptor is absent on both radioresistant parenchymal and bone marrow-derived cells will chimeric mice challenged with a highly invasive, noncytolytic...

  20. Synthesis, theoretical and structural analyses, and enantiopharmacology of 3-carboxy homologs of AMPA

    DEFF Research Database (Denmark)

    Brehm, Lotte; Greenwood, Jeremy R; Sløk, Frank A

    2004-01-01

    cell lines, were used to study the effects of the five compounds at metabotropic Glu receptors. In accordance with ligand-receptor complexes known from X-ray crystallography, the conformationally restricted Glu analog 1 was inactive at all Glu receptors studied, and the R-forms of ACPA and Ethyl...

  1. NMDA receptor antagonists interventions in schizophrenia: Meta-analysis of randomized, placebo-controlled trials.

    Science.gov (United States)

    Kishi, Taro; Iwata, Nakao

    2013-09-01

    We examined whether N-methyl d-aspartate (NMDA) receptor antagonists as adjunctive therapy have therapeutic potential for schizophrenia treatment. Systematic review of PubMed, Cochrane Library, PsycINFO and Google Scholar up until October 2012 and meta-analysis of randomized placebo-controlled trials were performed. Risk ratio (RR), 95% confidence intervals (CI), numbers-needed-to-harm (NNH), and standardized mean difference (SMD) were calculated. Results were across 8 studies and 406 patients (85.5% schizophrenia related disorder and 14.5% bipolar disorder) were included (amantadine: 5 trials and 220 patients, memantine: 3 trials and 186 patients). NMDA receptor antagonists (NMDAR-ANTs) as adjunctive therapy were not superior to placebo in overall (SMD = -0.25, CI = -0.72, 0.23, p = 0.31, N = 6, n = 347), positive symptoms (SMD = -0.20, CI = -0.70, 0.31, p = 0.44, N = 4, n = 205), and negative symptoms (SMD = -0.69, CI = -1.65, 0.27, p = 0.16, N = 4, n = 205), and Clinical Global Impression Severity scale (SMD = -0.27, CI = -1.20, 0.65, p = 0.56, N = 3, n = 177). There was also no significant difference in discontinuation rate between NMDAR-ANTs and placebo treatments (all cause: RR = 1.23, CI = 0.89-1.70, p = 0.20, N = 8, n = 396, side effects: RR = 1.86, CI = 0.84-4.13, p = 0.13, N = 6, n = 359, inefficacy/worsening psychosis: RR = 0.70, CI = 0.20-2.38, p = 0.56, N = 7, n = 380). However, memantine was favorable compared with placebo in Mini-Mental State Examination in schizophrenia (SMD = -0.77, CI = -1.27, -0.28, p = 0.002, N = 3, n = 71). While NMDAR-ANTs caused weight loss compared with placebo (SMD = -0.42, CI = -0.73, -0.11, p = 0.008, N = 3, n = 165), amantadine caused more frequent insomnia than placebo (RR = 3.83, CI = 1.41-10.38, p = 0.008, NNH = 9, p = 0.002, N = 2, n = 147). Our results indicate that NMDAR-ANTs as adjunctive therapy may improve

  2. Homeostatic regulation of excitatory synapses on striatal medium spiny neurons expressing the D2 dopamine receptor.

    Science.gov (United States)

    Thibault, Dominic; Giguère, Nicolas; Loustalot, Fabien; Bourque, Marie-Josée; Ducrot, Charles; El Mestikawy, Salah; Trudeau, Louis-Éric

    2016-05-01

    Striatal medium spiny neurons (MSNs) are contacted by glutamatergic axon terminals originating from cortex, thalamus and other regions. The striatum is also innervated by dopaminergic (DAergic) terminals, some of which release glutamate as a co-transmitter. Despite evidence for functional DA release at birth in the striatum, the role of DA in the establishment of striatal circuitry is unclear. In light of recent work suggesting activity-dependent homeostatic regulation of glutamatergic terminals on MSNs expressing the D2 DA receptor (D2-MSNs), we used primary co-cultures to test the hypothesis that stimulation of DA and glutamate receptors regulates the homeostasis of glutamatergic synapses on MSNs. Co-culture of D2-MSNs with mesencephalic DA neurons or with cortical neurons produced an increase in spines and functional glutamate synapses expressing VGLUT2 or VGLUT1, respectively. The density of VGLUT2-positive terminals was reduced by the conditional knockout of this gene from DA neurons. In the presence of both mesencephalic and cortical neurons, the density of synapses reached the same total, compatible with the possibility of a homeostatic mechanism capping excitatory synaptic density. Blockade of D2 receptors increased the density of cortical and mesencephalic glutamatergic terminals, without changing MSN spine density or mEPSC frequency. Combined blockade of AMPA and NMDA glutamate receptors increased the density of cortical terminals and decreased that of mesencephalic VGLUT2-positive terminals, with no net change in total excitatory terminal density or in mEPSC frequency. These results suggest that DA and glutamate signaling regulate excitatory inputs to striatal D2-MSNs at both the pre- and postsynaptic level, under the influence of a homeostatic mechanism controlling functional output of the circuit.

  3. Involvement of hippocampal NMDA receptors in retrieval of spontaneous object recognition memory in rats.

    Science.gov (United States)

    Iwamura, Etsushi; Yamada, Kazuo; Ichitani, Yukio

    2016-07-01

    The involvement of hippocampal N-methyl-d-aspartate (NMDA) receptors in the retrieval process of spontaneous object recognition memory was investigated. The spontaneous object recognition test consisted of three phases. In the sample phase, rats were exposed to two identical objects several (2-5) times in the arena. After the sample phase, various lengths of delay intervals (24h-6 weeks) were inserted (delay phase). In the test phase in which both the familiar and the novel objects were placed in the arena, rats' novel object exploration behavior under the hippocampal treatment of NMDA receptor antagonist, AP5, or vehicle was observed. With 5 exposure sessions in the sample phase (experiment 1), AP5 treatment in the test phase significantly decreased discrimination ratio when the delay was 3 weeks but not when it was one week. On the other hand, with 2 exposure sessions in the sample phase (experiment 2) in which even vehicle-injected control animals could not discriminate the novel object from the familiar one with a 3 week delay, AP5 treatment significantly decreased discrimination ratio when the delay was one week, but not when it was 24h. Additional experiment (experiment 3) showed that the hippocampal treatment of an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist, NBQX, decreased discrimination ratio with all delay intervals tested (24h-3 weeks). Results suggest that hippocampal NMDA receptors play an important role in the retrieval of spontaneous object recognition memory especially when the memory trace weakens. Copyright © 2016. Published by Elsevier B.V.

  4. Classical and Non-Classical Roles for Pre-Receptor Control of DHT Metabolism in Prostate Cancer Progression.

    Science.gov (United States)

    Zhang, Ailin; Zhang, Jiawei; Plymate, Stephen; Mostaghel, Elahe A

    2016-04-01

    Androgens play an important role in prostate cancer (PCa) development and progression. Accordingly, androgen deprivation therapy remains the front-line treatment for locally recurrent or advanced PCa, but patients eventually relapse with the lethal form of the disease termed castration resistant PCa (CRPC). Importantly, castration does not eliminate androgens from the prostate tumor microenvironment which is characterized by elevated tissue androgens that are well within the range capable of activating the androgen receptor (AR). In this mini-review, we discuss emerging data that suggest a role for the enzymes mediating pre-receptor control of dihydrotestosterone (DHT) metabolism, including AKR1C2, HSD17B6, HSD17B10, and the UGT family members UGT2B15 and UGT2B17, in controlling intratumoral androgen levels, and thereby influencing PCa progression. We review the expression of steroidogenic enzymes involved in this pathway in primary PCa and CRPC, the activity and regulation of these enzymes in PCa experimental models, and the impact of genetic variation in genes mediating pre-receptor DHT metabolism on PCa risk. Finally, we discuss recent data that suggests several of these enzymes may also play an unrecognized role in CRPC progression separate from their role in androgen inactivation.

  5. Hypothalamic growth hormone receptor (GHR) controls hepatic glucose production in nutrient-sensing leptin receptor (LepRb) expressing neurons.

    Science.gov (United States)

    Cady, Gillian; Landeryou, Taylor; Garratt, Michael; Kopchick, John J; Qi, Nathan; Garcia-Galiano, David; Elias, Carol F; Myers, Martin G; Miller, Richard A; Sandoval, Darleen A; Sadagurski, Marianna

    2017-05-01

    The GH/IGF-1 axis has important roles in growth and metabolism. GH and GH receptor (GHR) are active in the central nervous system (CNS) and are crucial in regulating several aspects of metabolism. In the hypothalamus, there is a high abundance of GH-responsive cells, but the role of GH signaling in hypothalamic neurons is unknown. Previous work has demonstrated that the Ghr gene is highly expressed in LepRb neurons. Given that leptin is a key regulator of energy balance by acting on leptin receptor (LepRb)-expressing neurons, we tested the hypothesis that LepRb neurons represent an important site for GHR signaling to control body homeostasis. To determine the importance of GHR signaling in LepRb neurons, we utilized Cre/loxP technology to ablate GHR expression in LepRb neurons (Lepr EYFPΔGHR ). The mice were generated by crossing the Lepr cre on the cre-inducible ROSA26-EYFP mice to GHR L/L mice. Parameters of body composition and glucose homeostasis were evaluated. Our results demonstrate that the sites with GHR and LepRb co-expression include ARH, DMH, and LHA neurons. Leptin action was not altered in Lepr EYFPΔGHR mice; however, GH-induced pStat5-IR in LepRb neurons was significantly reduced in these mice. Serum IGF-1 and GH levels were unaltered, and we found no evidence that GHR signaling regulates food intake and body weight in LepRb neurons. In contrast, diminished GHR signaling in LepRb neurons impaired hepatic insulin sensitivity and peripheral lipid metabolism. This was paralleled with a failure to suppress expression of the gluconeogenic genes and impaired hepatic insulin signaling in Lepr EYFPΔGHR mice. These findings suggest the existence of GHR-leptin neurocircuitry that plays an important role in the GHR-mediated regulation of glucose metabolism irrespective of feeding.

  6. Role of cardiac volume receptors in the control of ADH release during acute simulated weightlessness in man

    Science.gov (United States)

    Convertino, V. A.; Benjamin, B. A.; Keil, L. C.; Sandler, H.

    1984-01-01

    Hemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes, designed to induce central blood volume shifts in ten cardiac and one heart-lung transplant recipients, to assess the contribution of cardiac volume receptors in the control of ADH release during the initial acute phase of exposure to weightlessness. Each subject underwent 15 min of a sitting-control period (C) followed by 30 min of 6 deg headdown tilt (T) and 30 min of resumed sitting (S). Venous blood samples and cardiac dimensions were taken at 0 and 15 min of C; 5, 15, and 30 min of T; and 5, 15, and 30 min of S. Blood samples were analyzed for hematocrit, plasma osmolality, plasma renin activity (PRA), and ADH. Heart rate and blood pressure were recorded every two min. Plasma osmolality was not altered by posture changes. Mean left ventricular end-diastolic volume increased (P less than 0.05) from 90 ml in C to 106 ml in T and returned to 87 ml in S. Plasma ADH was reduced by 20 percent (P less than 0.05) with T, and returned to control levels with S. These responses were similar in six normal cardiac-innervated control subjects. These data may suggest that cardiac volume receptors are not the primary mechanism for the control of ADH release during acute central volume shifts in man.

  7. Resolution, configurational assignment, and enantiopharmacology at glutamate receptors of 2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA) and demethyl-ACPA

    DEFF Research Database (Denmark)

    Johansen, T N; Stensbøl, T B; Nielsen, B

    2001-01-01

    We have previously described (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA) as a potent agonist at the (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor subtype of (S)-glutamic acid (Glu) receptors. We now report the chromatographic resolution...... of ACPA and (RS)-2-amino-3-(3-carboxy-4-isoxazolyl)propionic acid (demethyl-ACPA) using a Sumichiral OA-5000 column. The configuration of the enantiomers of both compounds have been assigned based on X-ray crystallographic analyses, supported by circular dichroism spectra and elution orders on chiral HPLC...... columns. Furthermore, the enantiopharmacology of ACPA and demethyl-ACPA was investigated using radioligand binding and cortical wedge electrophysiological assay systems and cloned metabotropic Glu receptors. (S)-ACPA showed high affinity in AMPA binding (IC(50) = 0.025 microM), low affinity in kainic acid...

  8. Y2 receptor signalling in NPY neurons controls bone formation and fasting induced feeding but not spontaneous feeding.

    Science.gov (United States)

    Qi, Yue; Fu, Melissa; Herzog, Herbert

    2016-02-01

    Y2 receptors have been implicated in the development of obesity and are a potential target for obesity treatment due to their known role of inhibiting neuropeptide Y (NPY) induced feeding responses. However, the precise neuronal population on which Y2 receptors act to fulfil this role is less clear. Here we utilise a novel inducible, postnatal onset NPY neurons specific deletion model to investigate the functional consequences of loss of Y2 signalling in this population of neurons on feeding and energy homeostasis regulation. While the consequences of lack of Y2 signalling in NPY neurons are confirmed in terms of the uncoupling of suppression/increasing of NPY and pro-opiomelanocortin (POMC) mRNA expression in the arcuate nuclei (Arc), respectively, this lack of Y2 signalling surprisingly does not have any significant effect on spontaneous food intake. Fasting induced food intake, however, is strongly increased but only in the first 1h after re-feeding. Consequently no significant changes in body weight are being observed although body weight gain is increased in male mice after postnatal onset Y2 deletion. Importantly, another known function of central Y2 receptor signalling, the suppression of bone formation is conserved in this conditional model with whole body bone mineral content being decreased. Taken together this model confirms the critical role of Y2 signalling to control NPY and associated POMC expression in the Arc, but also highlights the possibility that others, non-NPY neuronal Y2 receptors, are also involved in controlling feeding and energy homeostasis regulation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Nicotinic acetylcholine receptor β2-subunits in the medial prefrontal cortex control attention

    NARCIS (Netherlands)

    Guillem, K.; Bloem, B.; Poorthuis, R.B.; Loos, M.; Smit, A.B.; Maskos, U.; Spijker, S.; Mansvelder, H.D.

    2011-01-01

    More than one-third of all people are estimated to experience mild to severe cognitive impairment as they age. Acetylcholine (ACh) levels in the brain diminish with aging, and nicotinic ACh receptor (nAChR) stimulation is known to enhance cognitive performance. The prefrontal cortex (PFC) is

  10. Protease-activated receptor-1 impairs host defense in murine pneumococcal pneumonia: a controlled laboratory study

    NARCIS (Netherlands)

    Schouten, Marcel; van't Veer, Cornelis; Roelofs, Joris J. T. H.; Levi, Marcel; van der Poll, Tom

    2012-01-01

    Streptococcus pneumoniae is the most common causative pathogen in community-acquired pneumonia. Protease-activated receptor-1 (PAR-1) is expressed by multiple cell types present in the lungs and can be activated by various proteases generated during acute inflammation. The cellular effect of PAR-1

  11. Synthesis and structure-activity studies on acidic amino acids and related diacids as NMDA receptor ligands

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1994-01-01

    The 3-isoxazolol amino acids (S)-2-amino-3-(3-hydroxy-5-methyl-4- isoxazolyl)propionic acid [(S)-AMPA, 2] and (R,S)-2-amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid (AMAA, 5a) (Figure 1) are potent and specific agonists at the AMPA and N-methyl-D-aspartic acid (NMDA) subtypes, respectively......, of (S)-glutamic acid (1) receptors. A number of amino acids and diacids structurally related to AMAA were synthesized and tested electrophysiologically and in receptor-binding assays. The hydroxymethyl analogue 7c of AMAA was an NMDA agonist approximately equipotent with AMAA in the [3H...... by molecular mechanics calculations. Compound 7a possesses extra steric bulk and shows significant restriction of conformational flexibility compared to AMAA and 7c, which may be determining factors for the observed differences in biological activity. Although the nitrogen atom of quinolinic acid (6) has very...

  12. Redistribution of ionotropic glutamate receptors detected by laser microdissection of the rat dentate gyrus 48 h following LTP induction in vivo.

    Directory of Open Access Journals (Sweden)

    Jeremy T T Kennard

    Full Text Available The persistence and input specificity of long-term potentiation (LTP make it attractive as a mechanism of information storage. In its initial phase, both in vivo and in vitro studies have shown that LTP is associated with increased membrane localization of AMPA receptor subunits, but the molecular basis of LTP maintenance over the long-term is still unclear. We have previously shown that expression of AMPA and NMDA receptor subunits is elevated in whole homogenates prepared from dentate gyrus 48 h after LTP induction in vivo. In the present study, we utilized laser microdissection (LMD techniques to determine whether AMPA and NMDA receptor upregulation occurs specifically in the stimulated regions of the dentate gyrus dendritic arbor. Receptor proteins GluN1, GluA1 and GluA2, as well as postsynaptic density protein of 95 kDa and tubulin were detected by Western blot analysis in microdissected samples. Gradients of expression were observed for GluN1 and GluA2, decreasing from the inner to the outer zones of the molecular layer, and were independent of LTP. When induced at medial perforant path synapses, LTP was associated with an apparent specific redistribution of GluA1 and GluN1 to the middle molecular layer that contains these synapses. These data indicate that glutamate receptor proteins are delivered specifically to dendritic regions possessing LTP-expressing synapses, and that these changes are preserved for at least 48 h.

  13. Endogenous Glucagon-like Peptide-1 Receptor Signaling in the Nucleus Tractus Solitarius is Required for Food Intake Control.

    Science.gov (United States)

    Alhadeff, Amber L; Mergler, Blake D; Zimmer, Derek J; Turner, Christopher A; Reiner, David J; Schmidt, Heath D; Grill, Harvey J; Hayes, Matthew R

    2017-06-01

    Alhough the glucagon-like peptide-1 (GLP-1) system is critical to energy balance control and is a target for obesity pharmacotherapies, the receptor-population-mediating effects of endogenous GLP-1 signaling are not fully understood. To address this, we developed a novel adeno-associated virus (AAV-GLP-1R) that utilizes short hairpin RNA to chronically knock down GLP-1 receptors (GLP-1R) in rats. As pharmacological studies highlight the hindbrain nucleus tractus solitarius (NTS) as a brain region important for GLP-1R-mediated effects on energy balance, AAV-GLP-1R was injected into the NTS to examine the role of endogenous NTS GLP-1R signaling in energy balance control. Chow intake and meal size were significantly increased following chronic NTS GLP-1R knockdown. In addition, NTS GLP-1R knockdown significantly increased self-administration of palatable food under both fixed and progressive ratio schedules of reinforcement. Collectively, these data demonstrate that endogenous NTS GLP-1R signaling is required for the control of food intake and motivation to feed, and provide a new strategy to investigate the importance of distinct GLP-1R populations in the control of a variety of functions.

  14. The farnesoid-X-receptor in myeloid cells controls CNS autoimmunity in an IL-10-dependent fashion.

    Science.gov (United States)

    Hucke, Stephanie; Herold, Martin; Liebmann, Marie; Freise, Nicole; Lindner, Maren; Fleck, Ann-Katrin; Zenker, Stefanie; Thiebes, Stephanie; Fernandez-Orth, Juncal; Buck, Dorothea; Luessi, Felix; Meuth, Sven G; Zipp, Frauke; Hemmer, Bernhard; Engel, Daniel Robert; Roth, Johannes; Kuhlmann, Tanja; Wiendl, Heinz; Klotz, Luisa

    2016-09-01

    Innate immune responses by myeloid cells decisively contribute to perpetuation of central nervous system (CNS) autoimmunity and their pharmacologic modulation represents a promising strategy to prevent disease progression in Multiple Sclerosis (MS). Based on our observation that peripheral immune cells from relapsing-remitting and primary progressive MS patients exhibited strongly decreased levels of the bile acid receptor FXR (farnesoid-X-receptor, NR1H4), we evaluated its potential relevance as therapeutic target for control of established CNS autoimmunity. Pharmacological FXR activation promoted generation of anti-inflammatory macrophages characterized by arginase-1, increased IL-10 production, and suppression of T cell responses. In mice, FXR activation ameliorated CNS autoimmunity in an IL-10-dependent fashion and even suppressed advanced clinical disease upon therapeutic administration. In analogy to rodents, pharmacological FXR activation in human monocytes from healthy controls and MS patients induced an anti-inflammatory phenotype with suppressive properties including control of effector T cell proliferation. We therefore, propose an important role of FXR in control of T cell-mediated autoimmunity by promoting anti-inflammatory macrophage responses.

  15. Occurrence and levels of glyphosate and AMPA in shallow lakes from the Pampean and Patagonian regions of Argentina.

    Science.gov (United States)

    Castro Berman, M; Marino, D J G; Quiroga, María Victoria; Zagarese, Horacio

    2018-06-01

    Glyphosate (N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide used to kill weeds that compete with commercial crops. In Argentina, the use of glyphosate-based herbicides increased dramatically (up to ∼200,000 tons on 2012) since the introduction of glyphosate-resistant crops, such as transgenic soy and resistant corn, and the adoption of non-till practices in the 1990's. Sallow lakes within the Pampa region may be potentially impacted by continuous herbicide usage. We surveyed 52 shallow lakes from the Pampa region (Buenos Aires Province, Argentina) to assess the occurrence and concentrations of glyphosate and its main degradation product (AMPA). For comparison, we also sampled 24 shallow lakes from an area with no agricultural use of glyphosate (Northern Patagonia). Glyphosate and AMPA were analyzed by UPLC-MS/MS ESI (±) in lake water, suspended particulate matter (SPM), and sediment samples. Within the Pampa region, glyphosate residues were detected in >40% of samples. Glyphosate residues were detected more frequently in sediment and surface water than in SPM samples. The mean (maximum) concentrations of glyphosate were 2.11 (4.52) μg l -1 for surface water; 0.10 (0.13) μg l -1 for SPM and 10.47 (20.34) μg kg -1 for sediment samples, respectively. Whereas, mean (maximum) concentrations of AMPA were 0.84 and (0.90) μg l -1 for surface water; 0.07 (0.07) μg l -1 for SPM; and 22.53 (32.89) μg kg -1 for sediment samples. The herbicide was not detected in samples from the Patagonian region. To our knowledge, this is the first study reporting the occurrence and concentrations of the herbicide in freshwater lakes of Argentina. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. A Double-Blind Placebo Controlled Trial of Piracetam Added to Risperidone in Patients with Autistic Disorder

    Science.gov (United States)

    Akhondzadeh, Shahin; Tajdar, Hamid; Mohammadi, Mohammad-Reza; Mohammadi, Mohammad; Nouroozinejad, Gholam-Hossein; Shabstari, Omid L.; Ghelichnia, Hossein-Ali

    2008-01-01

    It has been reported that autism is a hypoglutamatergic disorder. Therefore, it was of interest to assess the efficacy of piracetam, a positive modulator of AMPA-sensitive glutamate receptors in autistic disorder. About 40 children between the ages three and 11 years (inclusive) with a DSM IV clinical diagnosis of autism and who were outpatients…

  17. Receptor kinase-mediated control of primary active proton pumping at the plasma membrane

    DEFF Research Database (Denmark)

    Fuglsang, Anja Thoe; Kristensen, Astrid; Cuin, Tracey A.

    2014-01-01

    Acidification of the cell wall space outside the plasma membrane is required for plant growth and is the result of proton extrusion by the plasma membrane-localized H+-ATPases. Here we show that the major plasma membrane proton pumps in Arabidopsis, AHA1 and AHA2, interact directly in vitro...... and in planta with PSY1R, a receptor kinase of the plasma membrane that serves as a receptor for the peptide growth hormone PSY1. The intracellular protein kinase domain of PSY1R phosphorylates AHA2/AHA1 at Thr-881, situated in the autoinhibitory region I of the C-terminal domain. When expressed in a yeast...... heterologous expression system, the introduction of a negative charge at this position caused pump activation. Application of PSY1 to plant seedlings induced rapid in planta phosphorylation at Thr-881, concomitant with an instantaneous increase in proton efflux from roots. The direct interaction between AHA2...

  18. Vitamin D controls T cell antigen receptor signaling and activation of human T cells

    DEFF Research Database (Denmark)

    von Essen, Marina Rode; Kongsbak-Wismann, Martin; Schjerling, Peter

    2010-01-01

    Phospholipase C (PLC) isozymes are key signaling proteins downstream of many extracellular stimuli. Here we show that naive human T cells had very low expression of PLC-gamma1 and that this correlated with low T cell antigen receptor (TCR) responsiveness in naive T cells. However, TCR triggering...... led to an upregulation of approximately 75-fold in PLC-gamma1 expression, which correlated with greater TCR responsiveness. Induction of PLC-gamma1 was dependent on vitamin D and expression of the vitamin D receptor (VDR). Naive T cells did not express VDR, but VDR expression was induced by TCR...... signaling via the alternative mitogen-activated protein kinase p38 pathway. Thus, initial TCR signaling via p38 leads to successive induction of VDR and PLC-gamma1, which are required for subsequent classical TCR signaling and T cell activation....

  19. Behavioral control by striatal adenosine A2A -dopamine D2 receptor heteromers.

    Science.gov (United States)

    Taura, J; Valle-León, M; Sahlholm, K; Watanabe, M; Van Craenenbroeck, K; Fernández-Dueñas, V; Ferré, S; Ciruela, F

    2018-04-01

    G protein-coupled receptors (GPCR) exhibit the ability to form receptor complexes that include molecularly different GPCR (ie, GPCR heteromers), which endow them with singular functional and pharmacological characteristics. The relative expression of GPCR heteromers remains a matter of intense debate. Recent studies support that adenosine A 2A receptors (A 2A R) and dopamine D 2 receptors (D 2 R) predominantly form A 2A R-D 2 R heteromers in the striatum. The aim of the present study was evaluating the behavioral effects of pharmacological manipulation and genetic blockade of A 2A R and D 2 R within the frame of such a predominant striatal heteromeric population. First, in order to avoid possible strain-related differences, a new D 2 R-deficient mouse with the same genetic background (CD-1) than the A 2A R knock-out mouse was generated. Locomotor activity, pre-pulse inhibition (PPI) and drug-induced catalepsy were then evaluated in wild-type, A 2A R and D 2 R knock-out mice, with and without the concomitant administration of either the D 2 R agonist sumanirole or the A 2A R antagonist SCH442416. SCH442416-mediated locomotor effects were demonstrated to be dependent on D 2 R signaling. Similarly, a significant dependence on A 2A R signaling was observed for PPI and for haloperidol-induced catalepsy. The results could be explained by the existence of one main population of striatal postsynaptic A 2A R-D 2 R heteromers, which may constitute a relevant target for the treatment of Parkinson's disease and other neuropsychiatric disorders. © 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  20. A single amino acid residue controls Ca2+ signaling by an octopamine receptor from Drosophila melanogaster

    OpenAIRE

    Hoff, Max; Balfanz, Sabine; Ehling, Petra; Gensch, Thomas; Baumann, Arnd

    2011-01-01

    Rhythmic activity of cells and cellular networks plays an important role in physiology. In the nervous system oscillations of electrical activity and/or second messenger concentrations are important to synchronize neuronal activity. At the molecular level, rhythmic activity can be initiated by different routes. We have recently shown that an octopamine-activated G-protein-coupled receptor (GPCR; DmOctα1Rb, CG3856) from Drosophila initiates Ca2+ oscillations. Here, we have unraveled the molecu...

  1. Bradykinin receptor blockade restores the baroreflex control of renal sympathetic nerve activity in cisplatin-induced renal failure rats.

    Science.gov (United States)

    Abdulla, M H; Duff, M; Swanton, H; Johns, E J

    2016-11-01

    This study investigated the effect of renal bradykinin B1 and B2 receptor blockade on the high- and low-pressure baroreceptor reflex regulation of renal sympathetic nerve activity (RSNA) in rats with cisplatin-induced renal failure. Cisplatin (5 mg/kg) or saline was given intraperitoneally 4 days prior to study. Following chloralose/urethane anaesthesia, rats were prepared for measurement of mean arterial pressure (MAP), heart rate and RSNA and received intrarenal infusions of either Lys-[des-Arg 9 , Leu 8 ]-bradykinin (LBK), a bradykinin B1 receptor blocker, or bradyzide (BZ), a bradykinin B2 receptor blocker. RSNA baroreflex gain curves and renal sympatho-inhibitory responses to volume expansion (VE) were obtained. In the control and renal failure groups, basal MAP (89 ± 3 vs. 80 ± 8 mmHg) and RSNA (2.0 ± 0.3 vs. 1.7 ± 0.6 μV.s) were similar but HR was lower in the latter group (331 ± 8 vs. 396 ± 9 beats/min). The baroreflex gain for RSNA in the renal failure rats was 39% (P renal failure rats. Intrarenal LBK infusion in the renal failure rats normalized the VE induced renal sympatho-inhibition whereas BZ only partially restored the response. These findings suggest that pro-inflammatory bradykinin acting at different receptors within the kidney generates afferent neural signals which impact differentially within the central nervous system on high- and low-pressure regulation of RSNA. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  2. Spinal cord compression injury in lysophosphatidic acid 1 receptor-null mice promotes maladaptive pronociceptive descending control.

    Science.gov (United States)

    Suardíaz, M; Galan-Arriero, I; Avila-Martin, G; Estivill-Torrús, G; de Fonseca, F R; Chun, J; Gómez-Soriano, J; Bravo-Esteban, E; Taylor, J

    2016-02-01

    Although activation of the lysophosphatidic acid receptor 1 (LPA1) is known to mediate pronociceptive effects in peripheral pain models, the role of this receptor in the modulation of spinal nociception following spinal cord injury (SCI) is unknown. In this study, LPA1 regulation of spinal excitability mediated by supraspinal descending antinociceptive control systems was assessed following SCI in both wild-type (WT) and maLPA1-null receptor mice. The effect of a T8 spinal compression in WT and maLPA1-null mice was assessed up to 1 month after SCI using histological, immunohistochemical and behavioural techniques analysis including electrophysiological recording of noxious toes-Tibialis Anterior (TA) stimulus-response reflex activity. The effect of a T3 paraspinal transcutaneous electrical conditioning stimulus on TA noxious reflex temporal summation was also assessed. Histological analysis demonstrated greater dorsolateral funiculus damage after SCI in maLPA1-null mice, without a change in the stimulus-response function of the TA noxious reflex when compared to WT mice. While T3 conditioning stimulation in the WT group inhibited noxious TA reflex temporal summation after SCI, this stimulus strongly excited TA reflex temporal summation in maLPA1-null mice. The functional switch from descending inhibition to maladaptive facilitation of central excitability of spinal nociception demonstrated in maLPA1-null mice after SCI was unrelated to a general change in reflex activity. These data suggest that the LPA1 receptor is necessary for inhibition of temporal summation of noxious reflex activity, partly mediated via long-tract descending modulatory systems acting at the spinal level. © 2015 European Pain Federation - EFIC®

  3. DMPD: The involvement of the interleukin-1 receptor-associated kinases (IRAKs) incellular signaling networks controlling inflammation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available ncellular signaling networks controlling inflammation. Ringwood L, Li L. Cytokine. 2008 Apr;42(1):1-7. Epub ...ases (IRAKs) incellular signaling networks controlling inflammation. PubmedID 182...49132 Title The involvement of the interleukin-1 receptor-associated kinases (IRAKs) incellular signaling networks controlling

  4. Habit learning and the genetics of the dopamine D3 receptor: evidence from patients with schizophrenia and healthy controls.

    Science.gov (United States)

    Kéri, Szabolcs; Juhász, Anna; Rimanóczy, Agnes; Szekeres, György; Kelemen, Oguz; Cimmer, Csongor; Szendi, István; Benedek, György; Janka, Zoltán

    2005-06-01

    In this study, the authors investigated the relationship between the Ser9Gly (SG) polymorphism of the dopamine D3 receptor (DRD3) and striatal habit learning in healthy controls and patients with schizophrenia. Participants were given the weather prediction task, during which probabilistic cue-response associations were learned for tarot cards and weather outcomes (rain or sunshine). In both healthy controls and patients with schizophrenia, participants with Ser9Ser (SS) genotype did not learn during the early phase of the task (1-50 trials), whereas participants with SG genotype did so. During the late phase of the task (51-100 trials), both participants with SS and SG genotype exhibited significant learning. Learning rate was normal in patients with schizophrenia. These results suggest that the DRD3 variant containing glycine is associated with more efficient striatal habit learning in healthy controls and patients with schizophrenia. (c) 2005 APA, all rights reserved.

  5. Modeling the receptor pharmacology, pharmacokinetics, and pharmacodynamics of NKTR-214, a kinetically-controlled interleukin-2 (IL2 receptor agonist for cancer immunotherapy.

    Directory of Open Access Journals (Sweden)

    Deborah Charych

    Full Text Available Cytokines are potent immune modulating agents but are not ideal medicines in their natural form due to their short half-life and pleiotropic systemic effects. NKTR-214 is a clinical-stage biologic that comprises interleukin-2 (IL2 protein bound by multiple releasable polyethylene glycol (PEG chains. In this highly PEG-bound form, the IL2 is inactive; therefore, NKTR-214 is a biologic prodrug. When administered in vivo, the PEG chains slowly release, creating a cascade of increasingly active IL2 protein conjugates bound by fewer PEG chains. The 1-PEG-IL2 and 2-PEG-IL2 species derived from NKTR-214 are the most active conjugated-IL2 species. Free-IL2 protein is undetectable in vivo as it is eliminated faster than formed. The PEG chains on NKTR-214 are located at the region of IL2 that contacts the alpha (α subunit of the heterotrimeric IL2 receptor complex, IL2Rαβγ, reducing its ability to bind and activate the heterotrimer. The IL2Rαβγ complex is constitutively expressed on regulatory T cells (Tregs. Therefore, without the use of mutations, PEGylation reduces the affinity for IL2Rαβγ to a greater extent than for IL2Rβγ, the receptor complex predominant on CD8 T cells. NKTR-214 treatment in vivo favors activation of CD8 T cells over Tregs in the tumor microenvironment to provide anti-tumor efficacy in multiple syngeneic models. Mechanistic modeling based on in vitro and in vivo kinetic data provides insight into the mechanism of NKTR-214 pharmacology. The model reveals that conjugated-IL2 protein derived from NKTR-214 occupy IL-2Rβγ to a greater extent compared to free-IL2 protein. The model accurately describes the sustained in vivo signaling observed after a single dose of NKTR-214 and explains how the properties of NKTR-214 impart a unique kinetically-controlled immunological mechanism of action.

  6. Modeling the receptor pharmacology, pharmacokinetics, and pharmacodynamics of NKTR-214, a kinetically-controlled interleukin-2 (IL2) receptor agonist for cancer immunotherapy.

    Science.gov (United States)

    Charych, Deborah; Khalili, Samira; Dixit, Vidula; Kirk, Peter; Chang, Thomas; Langowski, John; Rubas, Werner; Doberstein, Stephen K; Eldon, Michael; Hoch, Ute; Zalevsky, Jonathan

    2017-01-01

    Cytokines are potent immune modulating agents but are not ideal medicines in their natural form due to their short half-life and pleiotropic systemic effects. NKTR-214 is a clinical-stage biologic that comprises interleukin-2 (IL2) protein bound by multiple releasable polyethylene glycol (PEG) chains. In this highly PEG-bound form, the IL2 is inactive; therefore, NKTR-214 is a biologic prodrug. When administered in vivo, the PEG chains slowly release, creating a cascade of increasingly active IL2 protein conjugates bound by fewer PEG chains. The 1-PEG-IL2 and 2-PEG-IL2 species derived from NKTR-214 are the most active conjugated-IL2 species. Free-IL2 protein is undetectable in vivo as it is eliminated faster than formed. The PEG chains on NKTR-214 are located at the region of IL2 that contacts the alpha (α) subunit of the heterotrimeric IL2 receptor complex, IL2Rαβγ, reducing its ability to bind and activate the heterotrimer. The IL2Rαβγ complex is constitutively expressed on regulatory T cells (Tregs). Therefore, without the use of mutations, PEGylation reduces the affinity for IL2Rαβγ to a greater extent than for IL2Rβγ, the receptor complex predominant on CD8 T cells. NKTR-214 treatment in vivo favors activation of CD8 T cells over Tregs in the tumor microenvironment to provide anti-tumor efficacy in multiple syngeneic models. Mechanistic modeling based on in vitro and in vivo kinetic data provides insight into the mechanism of NKTR-214 pharmacology. The model reveals that conjugated-IL2 protein derived from NKTR-214 occupy IL-2Rβγ to a greater extent compared to free-IL2 protein. The model accurately describes the sustained in vivo signaling observed after a single dose of NKTR-214 and explains how the properties of NKTR-214 impart a unique kinetically-controlled immunological mechanism of action.

  7. Extracellular signal-regulated kinases control expression of G protein-coupled receptor kinase 2 (GRK2)

    DEFF Research Database (Denmark)

    Theilade, Juliane; Lerche Hansen, Jakob; Haunsø, Stig

    2002-01-01

    G protein-coupled receptor kinase 2 (GRK2) phosphorylates G protein-coupled receptors resulting in uncoupling from G proteins. Receptors modulate GRK2 expression, however the mechanistic basis for this effect is largely unknown. Here we report a novel mechanism by which receptors use...

  8. Fyn kinase controls Fc{epsilon}RI receptor-operated calcium entry necessary for full degranulation in mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Miranda, Elizabeth; Ibarra-Sanchez, Alfredo [Departamento de Farmacobiologia, Centro de Investigacion y de Estudios Avanzados (Cinvestav), Sede Sur, Calzada de los Tenorios 235, Col. Granjas Coapa, CP 14330 Mexico City (Mexico); Gonzalez-Espinosa, Claudia, E-mail: cgonzal@cinvestav.mx [Departamento de Farmacobiologia, Centro de Investigacion y de Estudios Avanzados (Cinvestav), Sede Sur, Calzada de los Tenorios 235, Col. Granjas Coapa, CP 14330 Mexico City (Mexico)

    2010-01-22

    IgE-antigen-dependent crosslinking of the high affinity IgE receptor (Fc{epsilon}RI) on mast cells leads to degranulation, leukotriene synthesis and cytokine production. Calcium (Ca{sup 2+}) mobilization is a sine qua non requisite for degranulation, allowing the rapid secretion of stored pro-inflammatory mediators responsible for allergy symptoms. Fyn is a Src-family kinase that positively controls Fc{epsilon}RI-induced mast cell degranulation. However, our understanding of the mechanism connecting Fyn activation to secretion of pre-synthesized mediators is very limited. We analyzed Fc{epsilon}RI-dependent Ca{sup 2+} mobilization in bone marrow-derived mast cells (BMMCs) differentiated from WT and Fyn -/- knock out mice. Fyn -/- BMMCs showed a marked defect in extracellular Ca{sup 2+} influx after Fc{epsilon}RI crosslinking but not after thapsigargin addition. High concentrations of Gadolinium (Gd{sup 3+}) partially blocked Fc{epsilon}RI-induced Ca{sup 2+} influx in WT cells but, in contrast, completely inhibited Ca{sup 2+} mobilization in Fyn -/- cells. Low concentrations of an inhibitor of the canonical transient receptor potential (TRPC) Ca{sup 2+} channels (2-aminoethoxyphenyl-borane, 2-APB) blocked Fc{epsilon}RI-induced maximal Ca{sup 2+} rise in WT but not in Fyn -/- cells. Ca{sup 2+} entry through Fyn-controlled, 2-APB sensitive channels was found to be important for full degranulation and IL-2 mRNA accumulation in WT cells. Immunoprecipitation assays showed that Fyn kinase interacts with TRPC 3/6/7 channels after IgE-antigen stimulation, but its association is not related to protein tyrosine phosphorylation. Results indicate Fyn kinase mediates the receptor-dependent activation of TRPC channels that contribute to degranulation in Fc{epsilon}RI-stimulated mast cells.

  9. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature

    Science.gov (United States)

    Alawi, Khadija M.; Aubdool, Aisah A.; Liang, Lihuan; Wilde, Elena; Vepa, Abhinav; Psefteli, Maria-Paraskevi; Brain, Susan D.; Keeble, Julie E.

    2015-01-01

    Transient receptor potential vanilloid 1 (TRPV1) is involved in sensory nerve nociceptive signaling. Recently, it has been discovered that TRPV1 receptors also regulate basal body temperature in multiple species from mice to humans. In the present study, we investigated whether TRPV1 modulates basal sympathetic nervous system (SNS) activity. C57BL6/J wild-type (WT) mice and TRPV1 knockout (KO) mice were implanted with radiotelemetry probes for measurement of core body temperature. AMG9810 (50 mg/kg) or vehicle (2% DMSO/5% Tween 80/10 ml/kg saline) was injected intraperitoneally. Adrenoceptor antagonists or vehicle (5 ml/kg saline) was injected subcutaneously. In WT mice, the TRPV1 antagonist, AMG9810, caused significant hyperthermia, associated with increased noradrenaline concentrations in brown adipose tissue. The hyperthermia was significantly attenuated by the β-adrenoceptor antagonist propranolol, the mixed α-/β-adrenoceptor antagonist labetalol, and the α1-adrenoceptor antagonist prazosin. TRPV1 KO mice have a normal basal body temperature, indicative of developmental compensation. d-Amphetamine (potent sympathomimetic) caused hyperthermia in WT mice, which was reduced in TRPV1 KO mice, suggesting a decreased sympathetic drive in KOs. This study provides new evidence that TRPV1 controls thermoregulation upstream of the SNS, providing a potential therapeutic target for sympathetic hyperactivity thermoregulatory disorders.—Alawi, K. M., Aubdool, A. A., Liang, L., Wilde, E., Vepa, A., Psefteli, M.-P., Brain, S. D., Keeble, J. E. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature. PMID:26136480

  10. Peripheral tissue homing receptor control of naïve, effector, and memory CD8 T cell localization in lymphoid and non-lymphoid tissues.

    Science.gov (United States)

    Brinkman, C Colin; Peske, J David; Engelhard, Victor Henry

    2013-01-01

    T cell activation induces homing receptors that bind ligands on peripheral tissue vasculature, programing movement to sites of infection and injury. There are three major types of CD8 effector T cells based on homing receptor expression, which arise in distinct lymphoid organs. Recent publications indicate that naïve, effector, and memory T cell migration is more complex than once thought; while many effectors enter peripheral tissues, some re-enter lymph nodes (LN), and contain central memory precursors. LN re-entry can depend on CD62L or peripheral tissue homing receptors. Memory T cells in LN tend to express the same homing receptors as their forebears, but often are CD62Lneg. Homing receptors also control CD8 T cell tumor entry. Tumor vasculature has low levels of many peripheral tissue homing receptor ligands, but portions of it resemble high endothelial venules (HEV), enabling naïve T cell entry, activation, and subsequent effector activity. This vasculature is associated with positive prognoses in humans, suggesting it may sustain ongoing anti-tumor responses. These findings reveal new roles for homing receptors expressed by naïve, effector, and memory CD8 T cells in controlling entry into lymphoid and non-lymphoid tissues.

  11. PEST Motif Serine and Tyrosine Phosphorylation Controls Vascular Endothelial Growth Factor Receptor 2 Stability and Downregulation ▿

    Science.gov (United States)

    Meyer, Rosana D.; Srinivasan, Srimathi; Singh, Amrik J.; Mahoney, John E.; Gharahassanlou, Kobra Rezazadeh; Rahimi, Nader

    2011-01-01

    The internalization and degradation of vascular endothelial growth factor receptor 2 (VEGFR-2), a potent angiogenic receptor tyrosine kinase, is a central mechanism for the regulation of the coordinated action of VEGF in angiogenesis. Here, we show that VEGFR-2 is ubiquitinated in response to VEGF, and Lys 48-linked polyubiquitination controls its degradation via the 26S proteosome. The degradation and ubiquitination of VEGFR-2 is controlled by its PEST domain, and the phosphorylation of Ser1188/Ser1191 is required for the ubiquitination of VEGFR-2. F-box-containing β-Trcp1 ubiquitin E3 ligase is recruited to S1188/S1191 VEGFR-2 and mediates the ubiquitination and degradation of VEGFR-2. The PEST domain also controls the activation of p38 mitogen-activated protein kinase (MAPK) through phospho-Y1173. The activation of p38 stabilizes VEGFR-2, and its inactivation accelerates VEGFR-2 downregulation. The VEGFR-2-mediated activation of p38 is established through the protein kinase A (PKA)/MKK6 pathway. PKA is recruited to VEGFR-2 through AKAP1/AKAP149, and its phosphorylation requires Y1173 of VEGFR-2. The study has identified a unique mechanism in which VEGFR-2 stability and degradation is modulated. The PEST domain acts as a dual modulator of VEGFR-2; the phosphorylation of S1188/S1191 controls ubiquitination and degradation via β-Trcp1, where the phosphorylation of Y1173 through PKA/p38 MAPK controls the stability of VEGFR-2. PMID:21402774

  12. Estrogen-Related Receptors and the control of bone cell fate.

    Science.gov (United States)

    Carnesecchi, Julie; Vanacker, Jean-Marc

    2016-09-05

    Bone loss is naturally occurring in aging males and females and exacerbated in the latter after menopause, altogether leading to cumulative skeleton fragility and increased fracture risk. Two types of therapeutic strategies can be envisioned to counteract age- or menopause-associated bone loss, aiming at either reducing bone resorption exerted by osteoclasts or, alternatively, promoting bone formation by osteoblasts. We here summarize data suggesting that inhibition of the Estrogen-Related Receptors α and/or γ could promote bone formation and compensate for bone loss induced by ageing or estrogen-deficiency. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. IP3 Receptor-Dependent Cytoplasmic Ca2+ Signals Are Tightly Controlled by Cavβ3

    Directory of Open Access Journals (Sweden)

    Anouar Belkacemi

    2018-01-01

    Full Text Available Voltage-gated calcium channels (Cavs are major Ca2+ entry pathways in excitable cells. Their β subunits facilitate membrane trafficking of the channel’s ion-conducting α1 pore and modulate its gating properties. We report that one β subunit, β3, reduces Ca2+ release following stimulation of phospholipase C-coupled receptors and inositol 1,4,5-trisphosphate (IP3 formation. This effect requires the SH3-HOOK domain of Cavβ3, includes physical β3/IP3 receptor interaction, and prevails when agonist-induced IP3 formation is bypassed by photolysis of caged IP3. In agreement with β3 acting as a brake on Ca2+ release, fibroblast migration is enhanced in vitro, and in vivo, closure of skin wounds is accelerated in the absence of β3. To mediate specific physiological responses and to prevent Ca2+ toxicity, cytoplasmic Ca2+ signals must be tightly controlled. The described function of β3, unrelated to its function as a Cav subunit, adds to this tight control.

  14. The impact of luteal phase support on endometrial estrogen and progesterone receptor expression: a randomized control trial

    Directory of Open Access Journals (Sweden)

    Brezina Paul R

    2012-02-01

    Full Text Available Abstract Background To assess the impact of luteal phase support on the expression of estrogen receptor (ER alpha and progesterone receptors B (PR-B on the endometrium of oocyte donors undergoing controlled ovarian hyperstimulation (COH. Methods A prospective, randomized study was conducted in women undergoing controlled ovarian hyperstimulation for oocyte donation. Participants were randomized to receive no luteal support, vaginal progesterone alone, or vaginal progesterone plus orally administered 17 Beta estradiol. Endometrial biopsies were obtained at 4 time points in the luteal phase and evaluated by tissue microarray for expression of ER alpha and PR-B. Results One-hundred and eight endometrial tissue samples were obtained from 12 patients. No differences were found in expression of ER alpha and PR-B among all the specimens with the exception of one sample value. Conclusions The administration of progesterone during the luteal phase of COH for oocyte donor cycles, either with or without estrogen, does not significantly affect the endometrial expression of ER alpha and PR.

  15. N-methyl-D-aspartic acid receptor agonists

    DEFF Research Database (Denmark)

    Madsen, U; Frydenvang, Karla Andrea; Ebert, B

    1996-01-01

    (R,S)-2-Amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid [(R,S)-AMAA, 4] is a potent and selective agonist at the N-methyl-D-aspartic acid (NMDA) subtype of excitatory amino acid receptors. Using the Ugi "four-component condensation" method, the two diastereomers (2R)- and (2S)-2-[3-(benzyloxy......) showed peak affinity for [3H]AMPA receptor sites (IC50 = 72 +/- 13 microM) and was shown to be a more potent inhibitor of [3H]CPP binding (IC50 = 3.7 +/- 1.5 microM) than (S)-AMAA (9) (IC50 = 61 +/- 6.4 microM). Neither enantiomer of AMAA affected [3H]kainic acid receptor binding significantly...

  16. The therapeutic potential of nicotinic acetylcholine receptor agonists for pain control.

    Science.gov (United States)

    Decker, M W; Meyer, M D; Sullivan, J P

    2001-10-01

    Due to the limitations of currently available analgesics, a number of novel alternatives are currently under investigation, including neuronal nicotinic acetylcholine receptor (nAChR) agonists. During the 1990s, the discovery of the antinociceptive properties of the potent nAChR agonist epibatidine in rodents sparked interest in the analgesic potential of this class of compounds. Although epibatidine also has several mechanism-related toxicities, the identification of considerable nAChR diversity suggested that the toxicities and therapeutic actions of the compound might be mediated by distinct receptor subtypes. Consistent with this view, a number of novel nAChR agonists with antinociceptive activity and improved safety profiles in preclinical models have now been identified, including A-85380, ABT-594, DBO-83, SIB-1663 and RJR-2403. Of these, ABT-594 is the most advanced and is currently in Phase II clinical evaluation. Nicotinically-mediated antinociception has been demonstrated in a variety of rodent pain models and is likely mediated by the activation of descending inhibitory pathways originating in the brainstem with the predominant high-affinity nicotine site in brain, the alpha4beta2 subtype, playing a critical role. Thus, preclinical findings suggest that nAChR agonists have the potential to be highly efficacious treatments in a variety of pain states. However, clinical proof-of-principle studies will be required to determine if nAChR agonists are active in pathological pain.

  17. Stability of tramadol with three 5-HT3 receptor antagonists in polyolefin bags for patient-controlled delivery systems

    Directory of Open Access Journals (Sweden)

    Chen FC

    2016-06-01

    Full Text Available Fu-chao Chen,1 Jun Zhu,1 Bin Li,1 Fang-jun Yuan,1 Lin-hai Wang2 1Department of Pharmacy, Dongfeng Hospital, 2Department of Pharmacy, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, People’s Republic of China Background: Mixing 5-hydroxytryptamine-3 (5-HT3 receptor antagonists with patient-controlled analgesia (PCA solutions of tramadol has been shown to decrease the incidence of nausea and vomiting associated with the use of tramadol PCA for postoperative pain. However, such mixtures are not commercially available, and the stability of the drug combinations has not been duly studied. The study aimed to evaluate the stability of tramadol with three 5-HT3 receptor antagonists in 0.9% sodium chloride injection for PCA administration.Materials and methods: Test samples were prepared by adding 1,000 mg tramadol hydrochloride, 8 mg ondansetron hydrochloride, and 6 mg granisetron hydrochloride or 5 mg tropisetron hydrochloride to 100 mL of 0.9% sodium chloride injection in polyolefin bags. The samples were prepared in triplicates, stored at either 25°C or 4°C for 14 days, and assessed using the following compatibility parameters: precipitation, cloudiness, discoloration, and pH. Chemical stability was also determined using a validated high-pressure liquid chromatography method.Results: All of the mixtures were clear and colorless throughout the initial observation period. No change in the concentration of tramadol hydrochloride occurred with any of the 5-HT3 receptor antagonists during the 14 days. Similarly, little or no loss of the 5-HT3 receptor antagonists occurred over the 14-day period.Conclusion: Our results suggest that mixtures of tramadol hydrochloride, ondansetron hydrochloride, granisetron hydrochloride, or tropisetron hydrochloride in 0.9% sodium chloride injection were physically and chemically stable for 14 days when stored in polyolefin bags at both 4°C and 25°C. Keywords: tramadol, ondansetron, granisetron

  18. Long-term, repeated dose in vitro neurotoxicity of the glutamate receptor antagonist L-AP3, demonstrated in rat hippocampal slice cultures by using continuous propidium iodide incubation.

    Science.gov (United States)

    Kristensen, Bjarne W; Blaabjerg, Morten; Noraberg, Jens; Zimmer, Jens

    2007-05-01

    Most in vitro models are only used to assess short-term effects of test compounds. However, as demonstrated here, hippocampal slice cultures can be used for long-term studies. The test compound used was the metabotropic glutamate receptor antagonist, L(+)-2-amino-3-phosphonopropionic acid (L-AP3), which is known to be toxic in vivo after subchronic, but not acute, administration. Degenerative effects were monitored by measuring the cellular uptake of propidium iodide (PI; continuously present in the medium) and lactate dehydrogenase (LDH) leakage, and by using a panel of histological stains. Hippocampal slices, derived from 2-3 day old rats and grown for 3 weeks, were subsequently exposed for the next 3 weeks to 0, 10 or 100microM L-AP3, with PI (2microM) in the culture medium. Exposure to 100microM L-AP3 induced severe toxicity after 4-6 days, shown by massive PI uptake, LDH leakage, changes in MAP2 and GFAP immunostaining, and in Nissl and Timm staining. In contrast, 10microM L-AP3 did not induce detectable neuronal degeneration. Treatment with the NMDA receptor antagonist, MK-801, or the AMPA/KA receptor antagonist NBQX, together with 100microM L-AP3, reduced neurodegeneration down to close to control values. It is concluded that continuous incubation of hippocampal slice cultures with PI is technically feasible for use in studies of inducible neuronal degeneration over time.

  19. Ipsilateral feeding-specific circuits between the nucleus accumbens shell and the lateral hypothalamus: regulation by glutamate and GABA receptor subtypes.

    Science.gov (United States)

    Urstadt, Kevin R; Kally, Peter; Zaidi, Sana F; Stanley, B Glenn

    2013-04-01

    The nucleus accumbens shell (AcbSh) and the lateral hypothalamus (LH) are both involved in the control of food intake. Activation of GABA(A) receptors or blockade of AMPA and kainate receptors within the AcbSh induces feeding, as does blockade of GABA(A) receptors or activation of NMDA receptors in the LH. Further, evidence suggests that feeding induced via the AcbSh can be suppressed by LH inhibition. However, it is unclear if this suppression is specific to feeding. Adult male Sprague-Dawley rats with 3 intracranial guide cannulas, one unilaterally into the AcbSh and two bilaterally into the LH, were used to explore this issue. DNQX (1.25 μg) or muscimol (100 ng) infused into the AcbSh unilaterally elicited feeding, and this elicited intake was suppressed by bilateral LH injection of d-AP5 (2 μg) or muscimol (25 ng). The effectiveness of d-AP5 or muscimol infusion into either the LH site ipsilateral or contralateral to the AcbSh injection was compared. Ipsilateral LH injection of d-AP5 or muscimol was significantly more effective than contralateral injection in suppressing food intake initiated by AcbSh injection of DNQX or muscimol. These results add to the prior evidence that inhibition of the LH through pharmacological modulation of NMDA or GABA(A) receptors specifically suppresses feeding initiated by AcbSh inhibition, and that these two regions communicate via an ipsilateral circuit to specifically regulate feeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Floral organ abscission peptide IDA and its HAE/HSL2 receptors control cell separation during lateral root emergence.

    Science.gov (United States)

    Kumpf, Robert P; Shi, Chun-Lin; Larrieu, Antoine; Stø, Ida Myhrer; Butenko, Melinka A; Péret, Benjamin; Riiser, Even Sannes; Bennett, Malcolm J; Aalen, Reidunn B

    2013-03-26

    Throughout their life cycle, plants produce new organs, such as leaves, flowers, and lateral roots. Organs that have served their purpose may be shed after breakdown of primary cell walls between adjacent cell files at the site of detachment. In Arabidopsis, floral organs abscise after pollination, and this cell separation event is controlled by the peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA), which signals through the leucine-rich repeat receptor-like kinases HAESA (HAE) and HAESA-LIKE2 (HSL2). Emergence of new lateral root primordia, initiated deep inside the root under the influence of auxin, is similarly dependent on cell wall dissolution between cells in the overlaying endodermal, cortical, and epidermal tissues. Here we show that this process requires IDA, HAE, and HSL2. Mutation in these genes constrains the passage of the growing lateral root primordia through the overlaying layers, resulting in altered shapes of the lateral root primordia and of the overlaying cells. The HAE and HSL2 receptors are redundant in function during floral organ abscission, but during lateral root emergence they are differentially involved in regulating cell wall remodeling genes. In the root, IDA is strongly auxin-inducible and dependent on key regulators of lateral root emergence--the auxin influx carrier LIKE AUX1-3 and AUXIN RESPONSE FACTOR7. The expression levels of the receptor genes are only transiently induced by auxin, suggesting they are limiting factors for cell separation. We conclude that elements of the same cell separation signaling module have been adapted to function in different developmental programs.

  1. An alpha-adrenergic receptor mechanism controlling potassium permeability in the rat lacrimal gland acinar cell

    International Nuclear Information System (INIS)

    Parod, R.J.; Putney, J.W. Jr.

    1978-01-01

    Rat lacrimal gland slices, incubated in a balanced, buffered salt solution, were found to be physiologically stable for up to 2 hr with respect to 0 2 consumption, extracellular space, and water and ion content. The release of 86 Rb serves as a good substitute for 42 K in monitoring the movement of K through the cell membrane. Adrenaline appears to increase membrane permeability to K as evidenced by an increase in the rate of 86 Rb efflux. This response to adrenaline was blocked by phentolamine but not by propranolol and was mimicked by phenylephrine but not by isoprenaline. The magnitude of the 86 Rb release indicates that it is being released, at least in part, from the lacrimal gland acinar cell. It is concluded that the lacrimal gland acinar cell has an α-adrenergic receptor, activation of which leads to an increase in membrane permeability to K. (author)

  2. [¹¹C]-(+)-PHNO PET imaging of dopamine D(2/3) receptors in Parkinson's disease with impulse control disorders.

    Science.gov (United States)

    Payer, Doris E; Guttman, Mark; Kish, Stephen J; Tong, Junchao; Strafella, Antonio; Zack, Martin; Adams, John R; Rusjan, Pablo; Houle, Sylvain; Furukawa, Yoshiaki; Wilson, Alan A; Boileau, Isabelle

    2015-02-01

    Dopamine agonist medications with high affinity for the D3 dopamine receptor are commonly used to treat Parkinson's disease, and have been associated with pathological behaviors categorized under the umbrella of impulse control disorders (ICD). The aim of this study was to investigate whether ICD in Parkinson's patients are associated with greater D3 dopamine receptor availability. We used positron emission tomography (PET) radioligand imaging with the D3 dopamine receptor preferring agonist [¹¹C]-(+)-propyl-hexahydro-naphtho-oxazin (PHNO) in Parkinson's patients with (n = 11) and without (n = 21) ICD, and age-, sex-, and education-matched healthy control subjects (n = 18). Contrary to hypotheses, [¹¹C]-(+)-PHNO binding in D3 -rich brain areas was not elevated in Parkinson's patients with ICD compared with those without; instead, [¹¹C]-(+)-PHNO binding in ventral striatum was 20% lower (P = 0.011), correlating with two measures of ICD severity (r = -0.8 and -0.9), which may reflect higher dopamine tone in ventral striatum. In dorsal striatum, where [¹¹C]-(+)-PHNO binding is associated with D2 receptor levels, [¹¹C]-(+)-PHNO binding was elevated across patients compared with controls. We conclude that although D3 dopamine receptors have been linked to the occurrence of ICD in Parkinson's patients. Our findings do not support the hypothesis that D3 receptor levels are elevated in Parkinson's patients with ICD. We also did not find ICD-related abnormalities in D2 receptor levels. Our findings argue against the possibility that differences in D2/3 receptor levels can account for the development of ICD in PD; however, we cannot rule out that differences in dopamine levels (particularly in ventral striatum) may be involved. © 2015 International Parkinson and Movement Disorder Society.

  3. Early continuous white noise exposure alters l-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor subunit glutamate receptor 2 and gamma-aminobutyric acid type a receptor subunit beta3 protein expression in rat auditory cortex.

    Science.gov (United States)

    Xu, Jinghong; Yu, Liping; Zhang, Jiping; Cai, Rui; Sun, Xinde

    2010-02-15

    Auditory experience during the postnatal critical period is essential for the normal maturation of auditory function. Previous studies have shown that rearing infant rat pups under conditions of continuous moderate-level noise delayed the emergence of adult-like topographic representational order and the refinement of response selectivity in the primary auditory cortex (A1) beyond normal developmental benchmarks and indefinitely blocked the closure of a brief, critical-period window. To gain insight into the molecular mechanisms of these physiological changes after noise rearing, we studied expression of the AMPA receptor subunit GluR2 and GABA(A) receptor subunit beta3 in the auditory cortex after noise rearing. Our results show that continuous moderate-level noise rearing during the early stages of development decreases the expression levels of GluR2 and GABA(A)beta3. Furthermore, noise rearing also induced a significant decrease in the level of GABA(A) receptors relative to AMPA receptors. However, in adult rats, noise rearing did not have significant effects on GluR2 and GABA(A)beta3 expression or the ratio between the two units. These changes could have a role in the cellular mechanisms involved in the delayed maturation of auditory receptive field structure and topographic organization of A1 after noise rearing. Copyright 2009 Wiley-Liss, Inc.

  4. Dopamine D3 receptor Ser9Gly variant is associated with impulse control disorders in Parkinson's disease patients.

    Science.gov (United States)

    Krishnamoorthy, Soumya; Rajan, Roopa; Banerjee, Moinak; Kumar, Hardeep; Sarma, Gangadhara; Krishnan, Syam; Sarma, Sankara; Kishore, Asha

    2016-09-01

    Impulse control disorders (ICD) are reported to occur at variable frequencies in different ethnic groups. Genetic vulnerability is suspected to underlie the individual risk for ICD. We investigated whether the allelic variants of dopamine (DRD3), glutamate (GRIN2B) and serotonin (HTR2A) receptors are linked to ICD in Indian Parkinson's disease (PD) patients. We conducted a prospective, case-control study which included PD patients (70 with ICD, 100 without ICD categorized after direct psychiatric interview of patient and caregiver) and 285 healthy controls. Single nucleotide polymorphism (SNP) variants of DRD3 p.S9G (rs6280), GRIN2B c.2664C>T (rs1806201) and HTR2A c.102T>C (rs6313) were genotyped. Multivariate regression analysis revealed that DRD3 p.Ser9Gly (rs6280) heterozygous variant CT (OR = 2.22, 95% CI: 1.03-4.86, p = 0.041), higher daily Levodopa equivalent doses (LED) of drugs (for 100 mg LED, OR = 1.14, 95% CI: 1.01-1.29, p = 0.041), current dopamine agonist but not Levodopa use (OR = 2.16, 95% CI: 1.03-4.55, p = 0.042) and age of onset of motor symptoms under 50 years (OR 2.09, 95% CI: 1.05-4.18, p = 0.035) were independently associated with ICD. DRD3 p.Ser9Gly (rs6280) CT genotype is associated with ICD in Indian PD patients and this association is novel. Enhanced D3 receptor affinity due to gain-of-function conferred by the glycine residues could impair reward-risk assessment in the mesolimbic system and contribute to development of impulsive behaviour, in carriers of this genotype. Copyright © 2016. Published by Elsevier Ltd.

  5. The DAF-7/TGF-β signaling pathway regulates abundance of the C. elegans glutamate receptor GLR-1

    Science.gov (United States)

    McGehee, Annette M.; Moss, Benjamin J.; Juo, Peter

    2015-01-01

    Transforming growth factor-β (TGF-β) family signaling pathways have roles in both neuronal development and the regulation of synaptic function. Here we identify a novel role for the C. elegans DAF-7/TGF-β signaling pathway in the regulation of the AMPA-type glutamate receptor GLR-1. We found that the abundance of GLR-1 increases at synapses in the ventral nerve cord (VNC) of animals with loss-of-function mutations in multiple DAF-7/TGF-β pathway components including the TGF-β ligand DAF-7, the type I receptor DAF-1, and the Smads DAF-8 and DAF-14. The GLR-1 defect can be rescued by expression of daf-8 specifically in glr-1-expressing interneurons. The effect on GLR-1 was specific for the DAF-7 pathway because mutations in the DBL-1/TGF-β family pathway did not increase GLR-1 levels in the VNC. Immunoblot analysis indicates that total levels of GLR-1 protein are increased in neurons of DAF-7/TGF-β pathway mutants. The increased abundance of GLR-1 in the VNC of daf-7 pathway mutants is dependent on the transcriptional regulator DAF-3/Smad suggesting that DAF-3-dependent transcription controls GLR-1 levels. Furthermore, we found that glr-1 transcription is increased in daf-7 mutants based on a glr-1 transcriptional reporter. Together these results suggest that the DAF-7/TGF-β signaling pathway functions in neurons and negatively regulates the abundance of GLR-1, in part, by controlling transcription of the receptor itself. Finally, DAF-7/TGF-β pathway mutants exhibit changes in spontaneous locomotion that are dependent on endogenous GLR-1 and consistent with increased glutamatergic signaling. These results reveal a novel mechanism by which TGF-β signaling functions in the nervous system to regulate behavior. PMID:26054666

  6. The DAF-7/TGF-β signaling pathway regulates abundance of the Caenorhabditis elegans glutamate receptor GLR-1.

    Science.gov (United States)

    McGehee, Annette M; Moss, Benjamin J; Juo, Peter

    2015-07-01

    Transforming growth factor-β (TGF-β) family signaling pathways have roles in both neuronal development and the regulation of synaptic function. Here we identify a novel role for the Caenorhabditis elegans DAF-7/TGF-β signaling pathway in the regulation of the AMPA-type glutamate receptor GLR-1. We found that the abundance of GLR-1 increases at synapses in the ventral nerve cord (VNC) of animals with loss-of-function mutations in multiple DAF-7/TGF-β pathway components including the TGF-β ligand DAF-7, the type I receptor DAF-1, and the Smads DAF-8 and DAF-14. The GLR-1 defect can be rescued by expression of daf-8 specifically in glr-1-expressing interneurons. The effect on GLR-1 was specific for the DAF-7 pathway because mutations in the DBL-1/TGF-β family pathway did not increase GLR-1 levels in the VNC. Immunoblot analysis indicates that total levels of GLR-1 protein are increased in neurons of DAF-7/TGF-β pathway mutants. The increased abundance of GLR-1 in the VNC of daf-7 pathway mutants is dependent on the transcriptional regulator DAF-3/Smad suggesting that DAF-3-dependent transcription controls GLR-1 levels. Furthermore, we found that glr-1 transcription is increased in daf-7 mutants based on a glr-1 transcriptional reporter. Together these results suggest that the DAF-7/TGF-β signaling pathway functions in neurons and negatively regulates the abundance of GLR-1, in part, by controlling transcription of the receptor itself. Finally, DAF-7/TGF-β pathway mutants exhibit changes in spontaneous locomotion that are dependent on endogenous GLR-1 and consistent with increased glutamatergic signaling. These results reveal a novel mechanism by which TGF-β signaling functions in the nervous system to regulate behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Molecular pharmacology of 4-substituted glutamic acid analogues at ionotropic and metabotropic excitatory amino acid receptors

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Nielsen, B; Stensbøl, T B

    1997-01-01

    (subtypes 1alpha and 2), respectively, whereas (S)-4-methyleneglutamic acid showed high but rather non-selective affinity for the (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA), kainic acid, NMDA and mGlu receptors (subtypes 1alpha and 2). Although none of the compounds were specific......The pharmacology of (2S,4R)-4-methylglutamic acid, (2S,4S)-4-methylglutamic acid and (S)- and (R)-4-methyleneglutamic acids (obtained in high chemical and enantiomeric purity from racemic 4-methyleneglutamic acid by chiral HPLC using a Crownpak CR(+) column), was examined in binding experiments...... using rat brain ionotropic glutamate receptors, and in functional assays using cloned metabotropic glutamate (mGlu) receptors. As a notable result of these studies, (2S,4R)-4-methylglutamic acid and (2S,4S)-4-methylglutamic acid were shown to be selective for kainic acid receptors and mGlu receptors...

  8. Adiponectin, a downstream target gene of peroxisome proliferator-activated receptor γ, controls hepatitis B virus replication

    International Nuclear Information System (INIS)

    Yoon, Sarah; Jung, Jaesung; Kim, Taeyeung; Park, Sun; Chwae, Yong-Joon; Shin, Ho-Joon; Kim, Kyongmin

    2011-01-01

    In this study, HepG2-hepatitis B virus (HBV)-stable cells that did not overexpress HBx and HBx-deficient mutant-transfected cells were analyzed for their expression of HBV-induced, upregulated adipogenic and lipogenic genes. The mRNAs of CCAAT enhancer binding protein α (C/EBPα), peroxisome proliferator-activated receptor γ (PPARγ), adiponectin, liver X receptor α (LXRα), sterol regulatory element binding protein 1c (SREBP1c), and fatty acid synthase (FAS) were expressed at higher levels in HepG2-HBV and lamivudine-treated stable cells and HBx-deficient mutant-transfected cells than in the HepG2 cells. Lamivudine treatment reduced the mRNA levels of PPARγ and C/EBPα. Conversely, HBV replication was upregulated by adiponectin and PPARγ agonist rosiglitazone treatments and was downregulated by adiponectin siRNAs. Collectively, our results demonstrate that HBV replication and/or protein expression, even in the absence of HBx, upregulated adipogenic or lipogenic genes, and that the control of adiponectin might prove useful as a therapeutic modality for the treatment of chronic hepatitis B.

  9. The Murine Natural Cytotoxic Receptor NKp46/NCR1 Controls TRAIL Protein Expression in NK Cells and ILC1s

    Directory of Open Access Journals (Sweden)

    Sam Sheppard

    2018-03-01

    Full Text Available Summary: TRAIL is an apoptosis-inducing ligand constitutively expressed on liver-resident type 1 innate lymphoid cells (ILC1s and a subset of natural killer (NK cells, where it contributes to NK cell anti-tumor, anti-viral, and immunoregulatory functions. However, the intrinsic pathways involved in TRAIL expression in ILCs remain unclear. Here, we demonstrate that the murine natural cytotoxic receptor mNKp46/NCR1, expressed on ILC1s and NK cells, controls TRAIL protein expression. Using NKp46-deficient mice, we show that ILC1s lack constitutive expression of TRAIL protein and that NK cells activated in vitro and in vivo fail to upregulate cell surface TRAIL in the absence of NKp46. We show that NKp46 regulates TRAIL expression in a dose-dependent manner and that the reintroduction of NKp46 in mature NK cells deficient for NKp46 is sufficient to restore TRAIL surface expression. These studies uncover a link between NKp46 and TRAIL expression in ILCs with potential implications in pathologies involving NKp46-expressing cells. : Sheppard et al. find that mice deficient in the activating receptor NCR1/NKp46 (Ncr1−/− fail to express the apoptosis-inducing ligand TRAIL at the surface of group 1 innate lymphoid cells (ILC1s. Keywords: NK cell, natural killer cell, NKp46, ILC1, TRAIL, IL-15, IL-2

  10. Investigating the association between polymorphism of follicle-stimulating hormone receptor gene and ovarian response in controlled ovarian hyperstimulation

    Directory of Open Access Journals (Sweden)

    Mohammad Hasan Sheikhha

    2011-01-01

    Full Text Available Aim : The aim of the study was to investigate the association between follicle-stimulating hormone receptor (FSHR gene polymorphism at Position 680 and the outcomes of controlled ovarian hyperstimulation for in vitro fertilization and embryo transfer (IVF-ET in infertile women. Materials and Methods : One hundred and eight patients under 35 years of age who underwent IVF-ET procedures were included in this study. The hormonal profile and treatment of all patients were analyzed and FSHR polymorphism was examined by polymerase chain reaction-restriction fragment length polymorphism. Women from all groups were classified based on polymorphisms at Position 680, occupied either by asparagines (Asn or serine (Ser as Asn/Asn, Asn/Ser, and Ser/Ser genotype. Result : Our study showed that all patients in the Asn/Asn group were normal responders and in the Asn/Ser group 64.8% were normal responders and 21.1% and 14.1% were poor and hyper responders respectively. In the Ser/Ser group we did not have normal responders and 46.7% of these patients were poor responders and 53.3% were hyper responders. Conclusion : FSH receptor polymorphism is correlated with response to ovarian stimulation.

  11. Gene structure and expression of serotonin receptor HTR2C in hypothalamic samples from infanticidal and control sows

    Directory of Open Access Journals (Sweden)

    Quilter Claire R

    2012-04-01

    Full Text Available Abstract Background The serotonin pathways have been implicated in behavioural phenotypes in a number of species, including human, rat, mouse, dog and chicken. Components of the pathways, including the receptors, are major targets for drugs used to treat a variety of physiological and psychiatric conditions in humans. In our previous studies we have identified genetic loci potentially contributing to maternal infanticide in pigs, which includes a locus on the porcine X chromosome long arm. The serotonin receptor HTR2C maps to this region, and is therefore an attractive candidate for further study based on its function and its position in the genome. Results In this paper we describe the structure of the major transcripts produced from the porcine HTR2C locus using cDNA prepared from porcine hypothalamic and pooled total brain samples. We have confirmed conservation of sites altered by RNA editing in other mammalian species, and identified polymorphisms in the gene sequence. Finally, we have analysed expression and editing of HTR2C in hypothalamus samples from infanticidal and control animals. Conclusions The results confirm that although the expression of the long transcriptional variant of HTR2C is raised in infanticidal animals, the overall patterns of editing in the hypothalamus are similar between the two states. Sequences associated with the cDNA and genomic structures of HTR2C reported in this paper are deposited in GenBank under accession numbers FR720593, FR720594 and FR744452.

  12. μ opioid receptor activation hyperpolarizes respiratory-controlling Kölliker-Fuse neurons and suppresses post-inspiratory drive.

    Science.gov (United States)

    Levitt, Erica S; Abdala, Ana P; Paton, Julian F R; Bissonnette, John M; Williams, John T

    2015-10-01

    In addition to reductions in respiratory rate, opioids also cause aspiration and difficulty swallowing, indicating impairment of the upper airways. The Kölliker-Fuse (KF) maintains upper airway patency and a normal respiratory pattern. In this study, activation of μ opioid receptors in the KF reduced respiratory frequency and tidal volume in anaesthetized rats. Nerve recordings in an in situ preparation showed that activation of μ opioid receptors in the KF eliminated the post-inspiration phase of the respiratory cycle. In brain slices, μ opioid agonists hyperpolarized a distinct population (61%) of KF neurons by activation of an inwardly rectifying potassium conductance. These results suggest that KF neurons that are hyperpolarized by opioids could contribute to opioid-induced respiratory disturbances, particularly the impairment of upper airways. Opioid-induced respiratory effects include aspiration and difficulty swallowing, suggesting impairment of the upper airways. The pontine Kölliker-Fuse nucleus (KF) controls upper airway patency and regulates respiration, in particular the inspiratory/expiratory phase transition. Given the importance of the KF in coordinating respiratory pattern, the mechanisms of μ opioid receptor activation in this nucleus were investigated at the systems and cellular level. In anaesthetized, vagi-intact rats, injection of opioid agonists DAMGO or [Met(5) ]enkephalin (ME) into the KF reduced respiratory frequency and amplitude. The μ opioid agonist DAMGO applied directly into the KF of the in situ arterially perfused working heart-brainstem preparation of rat resulted in robust apneusis (lengthened low amplitude inspiration due to loss of post-inspiratory drive) that was rapidly reversed by the opioid antagonist naloxone. In brain slice preparations, activation of μ opioid receptors on KF neurons hyperpolarized a distinct population (61%) of neurons. As expected, the opioid-induced hyperpolarization reduced the excitability of

  13. Receptor protein tyrosine phosphatase alpha activates Src-family kinases and controls integrin-mediated responses in fibroblasts

    DEFF Research Database (Denmark)

    Su, J; Muranjan, M; Sap, J

    1999-01-01

    of tyrosine kinases, the activity of which is tightly controlled by inhibitory phosphorylation of a carboxyterminal tyrosine residue (Tyr527 in chicken c-Src); this phosphorylation induces the kinases to form an inactive conformation. Whereas the identity of such inhibitory Tyr527 kinases has been well...... established, no corresponding phosphatases have been identified that, under physiological conditions, function as positive regulators of c-Src and Fyn in fibroblasts. RESULTS: Receptor protein tyrosine phosphatase alpha (RPTPalpha) was inactivated by homologous recombination. Fibroblasts derived from...... these RPTPalpha-/- mice had impaired tyrosine kinase activity of both c-Src and Fyn, and this was accompanied by a concomitant increase in c-Src Tyr527 phosphorylation. RPTPalpha-/- fibroblasts also showed a reduction in the rate of spreading on fibronectin substrates, a trait that is a phenocopy of the effect...

  14. The EGF receptor and notch signaling pathways control the initiation of the morphogenetic furrow during Drosophila eye development.

    Science.gov (United States)

    Kumar, J P; Moses, K

    2001-07-01

    The onset of pattern formation in the developing Drosophila retina begins with the initiation of the morphogenetic furrow, the leading edge of a wave of retinal development that transforms a uniform epithelium, the eye imaginal disc into a near crystalline array of ommatidial elements. The initiation of this wave of morphogenesis is under the control of the secreted morphogens Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless (Wg). We show that the Epidermal Growth Factor Receptor and Notch signaling cascades are crucial components that are also required to initiate retinal development. We also show that the initiation of the morphogenetic furrow is the sum of two genetically separable processes: (1) the 'birth' of pattern formation at the posterior margin of the eye imaginal disc; and (2) the subsequent 'reincarnation' of retinal development across the epithelium.

  15. Mechanical stress regulates insulin sensitivity through integrin-dependent control of insulin receptor localization.

    Science.gov (United States)

    Kim, Jung; Bilder, David; Neufeld, Thomas P

    2018-01-15

    Insulin resistance, the failure to activate insulin signaling in the presence of ligand, leads to metabolic diseases, including type 2 diabetes. Physical activity and mechanical stress have been shown to protect against insulin resistance, but the molecular mechanisms remain unclear. Here, we address this relationship in the Drosophila larval fat body, an insulin-sensitive organ analogous to vertebrate adipose tissue and livers. We found that insulin signaling in Drosophila fat body cells is abolished in the absence of physical activity and mechanical stress even when excess insulin is present. Physical movement is required for insulin sensitivity in both intact larvae and fat bodies cultured ex vivo. Interestingly, the insulin receptor and other downstream components are recruited to the plasma membrane in response to mechanical stress, and this membrane localization is rapidly lost upon disruption of larval or tissue movement. Sensing of mechanical stimuli is mediated in part by integrins, whose activation is necessary and sufficient for mechanical stress-dependent insulin signaling. Insulin resistance develops naturally during the transition from the active larval stage to the immotile pupal stage, suggesting that regulation of insulin sensitivity by mechanical stress may help coordinate developmental programming with metabolism. © 2018 Kim et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Ionotropic Receptor-dependent moist and dry cells control hygrosensation in Drosophila.

    Science.gov (United States)

    Knecht, Zachary A; Silbering, Ana F; Cruz, Joyner; Yang, Ludi; Croset, Vincent; Benton, Richard; Garrity, Paul A

    2017-06-16

    Insects use hygrosensation (humidity sensing) to avoid desiccation and, in vectors such as mosquitoes, to locate vertebrate hosts. Sensory neurons activated by either dry or moist air ('dry cells' and 'moist cells') have been described in many insects, but their behavioral roles and the molecular basis of their hygrosensitivity remain unclear. We recently reported that Drosophila hygrosensation relies on three Ionotropic Receptors (IRs) required for dry cell function: IR25a, IR93a and IR40a (Knecht et al., 2016). Here, we discover Drosophila moist cells and show that they require IR25a and IR93a together with IR68a, a conserved, but orphan IR. Both IR68a- and IR40a-dependent pathways drive hygrosensory behavior: each is important for dry-seeking by hydrated flies and together they underlie moist-seeking by dehydrated flies. These studies reveal that humidity sensing in Drosophila , and likely other insects, involves the combined activity of two molecularly related but neuronally distinct hygrosensing systems.

  17. Prostate stromal cells express the progesterone receptor to control cancer cell mobility.

    Science.gov (United States)

    Yu, Yue; Lee, Jennifer Suehyun; Xie, Ning; Li, Estelle; Hurtado-Coll, Antonio; Fazli, Ladan; Cox, Michael; Plymate, Stephen; Gleave, Martin; Dong, Xuesen

    2014-01-01

    Reciprocal interactions between epithelium and stroma play vital roles for prostate cancer development and progression. Enhanced secretions of cytokines and growth factors by cancer associated fibroblasts in prostate tumors create a favorable microenvironment for cancer cells to grow and metastasize. Our previous work showed that the progesterone receptor (PR) was expressed specifically in prostate stromal fibroblasts and smooth muscle cells. However, the expression levels of PR and its impact to tumor microenvironment in prostate tumors are poorly understood. Immunohistochemistry assays are applied to human prostate tissue biopsies. Cell migration, invasion and proliferation assays are performed using human prostate cells. Real-time PCR and ELISA are applied to measure gene expression at molecular levels. Immunohistochemistry assays showed that PR protein levels were decreased in cancer associated stroma when compared with paired normal prostate stroma. Using in vitro prostate stromal cell models, we showed that conditioned media collected from PR positive stromal cells inhibited prostate cancer cell migration and invasion, but had minor suppressive impacts on cancer cell proliferation. PR suppressed the secretion of stromal derived factor-1 (SDF-1) and interlukin-6 (IL-6) by stromal cells independent to PR ligands. Blocking PR expression by siRNA or supplementation of exogenous SDF-1 or IL-6 to conditioned media from PR positive stromal cells counteracted the inhibitory effects of PR to cancer cell migration and invasion. Decreased expression of the PR in cancer associated stroma may contribute to the elevated SDF-1 and IL-6 levels in prostate tumors and enhance prostate tumor progression.

  18. Action control is mediated by prefrontal BDNF and glucocorticoid receptor binding.

    Science.gov (United States)

    Gourley, Shannon L; Swanson, Andrew M; Jacobs, Andrea M; Howell, Jessica L; Mo, Michelle; Dileone, Ralph J; Koleske, Anthony J; Taylor, Jane R

    2012-12-11

    Stressor exposure biases decision-making strategies from those based on the relationship between actions and their consequences to others restricted by stimulus-response associations. Chronic stressor exposure also desensitizes glucocorticoid receptors (GR) and diminishes motivation to acquire food reinforcement, although causal relationships are largely not established. We show that a history of chronic exposure to the GR ligand corticosterone or acute posttraining GR blockade with RU38486 makes rodents less able to perform actions based on their consequences. Thus, optimal GR binding is necessary for the consolidation of new response-outcome learning. In contrast, medial prefrontal (but not striatal) BDNF can account for stress-related amotivation, in that selective medial prefrontal cortical Bdnf knockdown decreases break-point ratios in a progressive-ratio task. Knockdown also increases vulnerability to RU38486. Despite the role of BDNF in dendritic spine reorganization, deep-layer spine remodeling does not obviously parallel progressive-ratio response patterns, but treatment with the Na(+)-channel inhibitor riluzole reverses corticosteroid-induced motivational deficits and restores prefrontal BDNF expression after corticosterone. We argue that when prefrontal neurotrophin systems are compromised, and GR-mediated hypothalamic-pituitary-adrenal axis feedback is desensitized (as in the case of chronic stress hormone exposure), amotivation and inflexible maladaptive response strategies that contribute to stress-related mood disorders result.

  19. The B-cell receptor controls fitness of MYC-driven lymphoma cells via GSK3β inhibition.

    Science.gov (United States)

    Varano, Gabriele; Raffel, Simon; Sormani, Martina; Zanardi, Federica; Lonardi, Silvia; Zasada, Christin; Perucho, Laura; Petrocelli, Valentina; Haake, Andrea; Lee, Albert K; Bugatti, Mattia; Paul, Ulrike; Van Anken, Eelco; Pasqualucci, Laura; Rabadan, Raul; Siebert, Reiner; Kempa, Stefan; Ponzoni, Maurilio; Facchetti, Fabio; Rajewsky, Klaus; Casola, Stefano

    2017-06-08

    Similar to resting mature B cells, where the B-cell antigen receptor (BCR) controls cellular survival, surface BCR expression is conserved in most mature B-cell lymphomas. The identification of activating BCR mutations and the growth disadvantage upon BCR knockdown of cells of certain lymphoma entities has led to the view that BCR signalling is required for tumour cell survival. Consequently, the BCR signalling machinery has become an established target in the therapy of B-cell malignancies. Here we study the effects of BCR ablation on MYC-driven mouse B-cell lymphomas and compare them with observations in human Burkitt lymphoma. Whereas BCR ablation does not, per se, significantly affect lymphoma growth, BCR-negative (BCR - ) tumour cells rapidly disappear in the presence of their BCR-expressing (BCR + ) counterparts in vitro and in vivo. This requires neither cellular contact nor factors released by BCR + tumour cells. Instead, BCR loss induces the rewiring of central carbon metabolism, increasing the sensitivity of receptor-less lymphoma cells to nutrient restriction. The BCR attenuates glycogen synthase kinase 3 beta (GSK3β) activity to support MYC-controlled gene expression. BCR - tumour cells exhibit increased GSK3β activity and are rescued from their competitive growth disadvantage by GSK3β inhibition. BCR - lymphoma variants that restore competitive fitness normalize GSK3β activity after constitutive activation of the MAPK pathway, commonly through Ras mutations. Similarly, in Burkitt lymphoma, activating RAS mutations may propagate immunoglobulin-crippled tumour cells, which usually represent a minority of the tumour bulk. Thus, while BCR expression enhances lymphoma cell fitness, BCR-targeted therapies may profit from combinations with drugs targeting BCR - tumour cells.

  20. Dietary approaches to stop hypertension influence on insulin receptor substrate-1gene expression: A randomized controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Marzieh Kafeshani

    2015-01-01

    Full Text Available Background: Insulin receptor substrate (IRS Type 1 is a main substrate for the insulin receptor, controls insulin signaling in skeletal muscle, adipose tissue, and the vascular, so it is an important candidate gene for insulin resistance (IR. We aimed to compare the effects of the Dietary Approaches to Stop Hypertension (DASH and Usual Dietary Advices (UDA on IRS1 gene expression in women at risk for cardiovascular disease. Materials and Methods: A randomized controlled clinical trial was performed in 44 women at risk for cardiovascular disease. Participants were randomly assigned to a UDA diet or the DASH diet. The DASH diet was rich in fruits, vegetables, whole grains, and low-fat dairy products and low in saturated fat, total fat, cholesterol, refined grains, and sweets, with a total of 2400 mg/day sodium. The UDA diet was a regular diet with healthy dietary advice. Gene expression was assessed by the real-time polymerase chain reaction at the first of study and after 12 weeks. Independent sample t-test and paired-samples t-test were used to compare means of all variables within and between two groups respectively. Results: IRS1 gene expression was increased in DASH group compared with UDA diet (P = 0.00. Weight and waist circumference decreased in DASH group significantly compared to the UDA group (P < 0.05 but the results between the two groups showed no significant difference. Conclusion: DASH diet increased IRS1 gene expression and probably has beneficial effects on IR risks.

  1. Association of estrogen receptor beta variants and serum levels of estradiol with risk of colorectal cancer: a case control study

    Directory of Open Access Journals (Sweden)

    Wu Huanlei

    2012-07-01

    Full Text Available Abstract Background Endogenous estrogens may play a vital role in colorectal tumorigenesis. Estrogen receptor beta is the predominant subtype which mediates the biological effect of estrogens, while loss of expression of estrogen receptor beta has been indicated as a common step in the development of colorectal cancer (CRC. Epidemiological studies have revealed several functional polymorphisms of estrogen receptor beta (ESR2 for cancer risk, but relevant study in CRC is limited, particularly in men. This study aimed to investigate the association of circulating estradiol and variations of ESR2 with CRC risk in men. Methods We initiated a case–control study consisting of 390 patients with CRC and 445 healthy controls in men only. We genotyped ESR2 single nucleotide polymorphisms (SNPs rs1256049 and rs4986938 and measured serum estradiol concentration using chemilluminescence immunoassay. Multivariable logistic regression model was performed to evaluate the associations between these variables and CRC risk. Results ESR2 rs1256049 CT/TT genotypes were associated with reduced risk of CRC (odds ratio [OR], 0.7, 95% confidence interval [CI], 0.5–1.0, while rs4986938 CT/TT genotypes were associated with increased risk of CRC (OR, 1.5, 95% CI, 1.0–2.1. In addition, the CRC risk increased with the number of risk genotypes of these two SNPs in a dose–response manner (Ptrend, 0.003. Specifically, subjects carrying risk genotypes of both SNPs had the highest risk of CRC (OR, 2.0, 95% CI, 1.3–3.3.. Moreover, serum estradiol concentration alone was associated with risk of CRC in men (OR, 1.2, 95% CI, 1.0–1.3. However, individuals presenting both rs4986938 CT/TT genotypes and high level of serum estradiol had a high risk of CRC (OR, 2.3, 95% CI, 1.4–3.9, compared with those presenting CC genotype and low level of serum estradiol. The similar joint results were not observed for SNP rs1256049. Conclusions These results suggest that endogenous

  2. Short-term sleep deprivation impairs spatial working memory and modulates expression levels of ionotropic glutamate receptor subunits in hippocampus.

    Science.gov (United States)

    Xie, Meilan; Yan, Jie; He, Chao; Yang, Li; Tan, Gang; Li, Chao; Hu, Zhian; Wang, Jiali

    2015-06-01

    Hippocampus-dependent learning memory is sensitive to sleep deprivation (SD). Although the ionotropic glutamate receptors play a vital role in synaptic plasticity and learning and memory, however, whether the expression of these receptor subunits is modulated by sleep loss remains unclear. In the present study, western blotting was performed by probing with specific antibodies against the ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA1, GluA2, GluA3, and against the N-methyl-d-aspartate (NMDA) glutamate receptor subunits GluN1, GluN2A, GluN2B. In hippocampus, down regulation of surface GluA1 and GluN2A surface expression were observed in both SD groups. However, surface expression level of GluA2, GluA3, GluN1 and GluN2B was significantly up-regulated in 8h-SD rats when compared to the 4h-SD rats. In parallel with the complex changes in AMPA and NMDA receptor subunit expressions, we found the 8h-SD impaired rat spatial working memory in 30-s-delay T-maze task, whereas no impairment of spatial learning was observed in 4h-SD rats. These results indicate that sleep loss alters the relative expression levels of the AMPA and NMDA receptors, thus affects the synaptic strength and capacity for plasticity and partially contributes to spatial memory impairment. Copyright © 2015. Published by Elsevier B.V.

  3. Night work and breast cancer risk defined by human epidermal growth factor receptor-2 (HER2) and hormone receptor status: A population-based case-control study in France.

    Science.gov (United States)

    Cordina-Duverger, Emilie; Koudou, Yves; Truong, Thérèse; Arveux, Patrick; Kerbrat, Pierre; Menegaux, Florence; Guénel, Pascal

    Night work has been associated with risk of breast cancer but this association needs to be confirmed. Because breast cancer is an etiologically heterogeneous disease, we explored the association of night work with breast cancer subtypes defined by tumor status (positive of negative) for estrogen-receptor (ER), progesterone-receptor (PR) and human epidermal growth factor-receptor 2 (HER2). Using the data from a case-control study in France including 975 cases and 1317 controls, we found that the odds ratios for ER+, PR+ or HER2+ breast cancers subtypes were significantly elevated, while no association with night shift work was observed for ER, PR or HER2-negative tumors. After stratification by menopausal status, the associations of night work with receptor-positive breast tumor subtypes were clearly seen in premenopausal women (odds ratios 2.04, 1.98 and 2.80, respectively) but did not appear in postmenopausal women. This study provides evidence that working at night may increase risk of ER, PR and HER2-positive subtypes of breast cancer particularly among premenopausal women.

  4. Ampa Co’i Ndai: Local Understanding of Kafā’a in Marriage among Eastern Indonesian Muslims

    Directory of Open Access Journals (Sweden)

    Atun Wardatun

    2016-12-01

    [Artikel ini adalah penelitian etnografi tentang praktik AMPA co’i ndai (ACN di kalangan masyarakat semi-urban muslim Bima di kawasan timur Indonesia. Budaya ini dilaksanakan dengan cara pengantin perempuan, dengan bantuan orang tua dan saudara perempuannya, menyediakan biaya pernikahan (co’i dan mahar. Tradisi ini dipraktikkan hanya ketika calon pengantin pria adalah pegawai negeri, yang diasumsikan memiliki status sosial yang lebih. Namun, saat resepsi pernikahan, deiumumkan bahwa biaya-biaya berasal dari pengantin pria. Narasi kehidupan dari sembilan belas perempuan yang terlibat mengungkapkan fungsi ACN sebagai mekanisme penyetaraan gender dengan meminimalkan relasi kuasa serta nmendudukkan pasangan untuk saling melengkapi dalam keluarga maupun masyarakat. Praktik ACN dapat dilihat sebagai bentuk lokal pemahaman konsep kafā’a, yang berarti “kesetaraan” untuk “melengkapi”. Namun, pemahaman lokal kafā’a ini merupakan bukti kompleksitas relasi kuasa dalam masalah gender.

  5. Insulin receptors

    International Nuclear Information System (INIS)

    Kahn, C.R.; Harrison, L.C.

    1988-01-01

    This book contains the proceedings on insulin receptors. Part A: Methods for the study of structure and function. Topics covered include: Method for purification and labeling of insulin receptors, the insulin receptor kinase, and insulin receptors on special tissues

  6. Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes

    Science.gov (United States)

    Petrovič, Pavol; Valent, Ivan; Cocherová, Elena; Pavelková, Jana

    2015-01-01

    The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases. PMID:26009544

  7. Prostate stromal cells express the progesterone receptor to control cancer cell mobility.

    Directory of Open Access Journals (Sweden)

    Yue Yu

    Full Text Available Reciprocal interactions between epithelium and stroma play vital roles for prostate cancer development and progression. Enhanced secretions of cytokines and growth factors by cancer associated fibroblasts in prostate tumors create a favorable microenvironment for cancer cells to grow and metastasize. Our previous work showed that the progesterone receptor (PR was expressed specifically in prostate stromal fibroblasts and smooth muscle cells. However, the expression levels of PR and its impact to tumor microenvironment in prostate tumors are poorly understood.Immunohistochemistry assays are applied to human prostate tissue biopsies. Cell migration, invasion and proliferation assays are performed using human prostate cells. Real-time PCR and ELISA are applied to measure gene expression at molecular levels.Immunohistochemistry assays showed that PR protein levels were decreased in cancer associated stroma when compared with paired normal prostate stroma. Using in vitro prostate stromal cell models, we showed that conditioned media collected from PR positive stromal cells inhibited prostate cancer cell migration and invasion, but had minor suppressive impacts on cancer cell proliferation. PR suppressed the secretion of stromal derived factor-1 (SDF-1 and interlukin-6 (IL-6 by stromal cells independent to PR ligands. Blocking PR expression by siRNA or supplementation of exogenous SDF-1 or IL-6 to conditioned media from PR positive stromal cells counteracted the inhibitory effects of PR to cancer cell migration and invasion.Decreased expression of the PR in cancer associated stroma may contribute to the elevated SDF-1 and IL-6 levels in prostate tumors and enhance prostate tumor progression.

  8. Role of medial prefrontal cortex serotonin 2A receptors in the control of retrieval of recognition memory in rats.

    Science.gov (United States)

    Bekinschtein, Pedro; Renner, Maria Constanza; Gonzalez, Maria Carolina; Weisstaub, Noelia

    2013-10-02

    Often, retrieval cues are not uniquely related to one specific memory, which could lead to memory interference. Controlling interference is particularly important during episodic memory retrieval or when remembering specific events in a spatiotemporal context. Despite a clear involvement of prefrontal cortex (PFC) in episodic memory in human studies, information regarding the mechanisms and neurotransmitter systems in PFC involved in memory is scarce. Although the serotoninergic system has been linked to PFC functionality and modulation, its role in memory processing is poorly understood. We hypothesized that the serotoninergic system in PFC, in particular the 5-HT2A receptor (5-HT2AR) could have a role in the control of memory retrieval. In this work we used different versions of the object recognition task in rats to study the role of the serotoninergic modulation in the medial PFC (mPFC) in memory retrieval. We found that blockade of 5-HT2AR in mPFC affects retrieval of an object in context memory in a spontaneous novelty preference task, while sparing single-item recognition memory. We also determined that 5-HT2ARs in mPFC are required for hippocampal-mPFC interaction during retrieval of this type of memory, suggesting that the mPFC controls the expression of memory traces stored in the hippocampus biasing retrieval to the most relevant one.

  9. Adenosine A2A Receptors Control Glutamatergic Synaptic Plasticity in Fast Spiking Interneurons of the Prefrontal Cortex

    Directory of Open Access Journals (Sweden)

    Amber Kerkhofs

    2018-03-01

    Full Text Available Adenosine A2A receptors (A2AR are activated upon increased synaptic activity to assist in the implementation of long-term plastic changes at synapses. While it is reported that A2AR are involved in the control of prefrontal cortex (PFC-dependent behavior such as working memory, reversal learning and effort-based decision making, it is not known whether A2AR control glutamatergic synapse plasticity within the medial PFC (mPFC. To elucidate that, we tested whether A2AR blockade affects long-term plasticity (LTP of excitatory post-synaptic potentials in pyramidal neurons and fast spiking (FS interneurons in layer 5 of the mPFC and of population spikes. Our results show that A2AR are enriched at mPFC synapses, where their blockade reversed the direction of plasticity at excitatory synapses onto layer 5 FS interneurons from LTP to long-term depression, while their blockade had no effect on the induction of LTP at excitatory synapses onto layer 5 pyramidal neurons. At the network level, extracellularly induced LTP of population spikes was reduced by A2AR blockade. The interneuron-specificity of A2AR in controlling glutamatergic synapse LTP may ensure that during periods of high synaptic activity, a proper excitation/inhibition balance is maintained within the mPFC.

  10. Controle de qualidade interlaboratorial em imuno-histoquímica: citoceratinas e receptor de estrógeno como modelos Interlaboratorial quality-control in immunohistochemistry: cytokeratins and estrogen receptors as models

    Directory of Open Access Journals (Sweden)

    Venâncio Avancini Ferreira Alves

    2004-06-01

    Full Text Available INTRODUÇÃO: O grande incremento do uso da imuno-histoquímica (IHQ em numerosos laboratórios de anatomia patológica amplia o poder de resolução diagnóstica, mas traz certo grau de heterogeneidade de procedimentos e resultados. Seguindo recentes propostas da literatura internacional, participantes do Clube de IHQ da Sociedade Brasileira de Patologia desenvolvem ações de controle de qualidade, aplicando protocolos de sua rotina à pesquisa de antígenos que sirvam como indicadores de qualidade da reação. MATERIAL E MÉTODO: Um total de dez laboratórios participou das duas etapas deste estudo, cujos marcadores foram pancitoceratinas e receptores de estrógeno. Com lâminas controle recebidas dos laboratórios, cada participante efetuou a técnica de IHQ conforme sua prática diária, retornando as lâminas juntamente com o formulário de procedimento. A avaliação semiquantificada de 0 a 4 da intensidade da reação específica e de 0 a 3 da coloração de fundo e da qualidade da técnica histológica foram atribuídas individual e sigilosamente durante a projeção em data show em reunião do Clube de IHQ, gerando um escore final. RESULTADOS E DISCUSSÃO: As variações na imunocoloração de citoceratinas e receptor de estrógeno não comprometeram sua detecção nas lâminas preparadas nos diversos laboratórios. Tais variações associaram-se à diversidade de sistemas de recuperação antigênica e de amplificação, resultando ora em imunopositividade menos intensa, ora em maior fundo. Outros estudos devem abordar questões de interpretação, incluindo-se critérios para semiquantificação.BACKGROUND: The expansion of the use of immunohistochemistry (IHC in numerous laboratories extends the power of diagnostic resolution, but may impart heterogeneity in procedures and results. Following recent international proposals, participants of the Club of IHC of the Brazilian Society of Pathology developed actions of quality control

  11. The CNS glucagon-like peptide-2 receptor in the control of energy balance and glucose homeostasis

    Science.gov (United States)

    2014-01-01

    The gut-brain axis plays a key role in the control of energy balance and glucose homeostasis. In response to luminal stimulation of macronutrients and microbiota-derived metabolites (secondary bile acids and short chain fatty acids), glucagon-like peptides (GLP-1 and -2) are cosecreted from endocrine L cells in the gut and coreleased from preproglucagonergic neurons in the brain stem. Glucagon-like peptides are proposed as key mediators for bariatric surgery-improved glycemic control and energy balance. Little is known about the GLP-2 receptor (Glp2r)-mediated physiological roles in the control of food intake and glucose homeostasis, yet Glp1r has been studied extensively. This review will highlight the physiological relevance of the central nervous system (CNS) Glp2r in the control of energy balance and glucose homeostasis and focuses on cellular mechanisms underlying the CNS Glp2r-mediated neural circuitry and intracellular PI3K signaling pathway. New evidence (obtained from Glp2r tissue-specific KO mice) indicates that the Glp2r in POMC neurons is essential for suppressing feeding behavior, gastrointestinal motility, and hepatic glucose production. Mice with Glp2r deletion selectively in POMC neurons exhibit hyperphagic behavior, accelerated gastric emptying, glucose intolerance, and hepatic insulin resistance. GLP-2 differentially modulates postsynaptic membrane excitability of hypothalamic POMC neurons in Glp2r- and PI3K-dependent manners. GLP-2 activates the PI3K-Akt-FoxO1 signaling pathway in POMC neurons by Glp2r-p85α interaction. Intracerebroventricular GLP-2 augments glucose tolerance, suppresses glucose production, and enhances insulin sensitivity, which require PI3K (p110α) activation in POMC neurons. Thus, the CNS Glp2r plays a physiological role in the control of food intake and glucose homeostasis. This review will also discuss key questions for future studies. PMID:24990862

  12. The GPCR membrane receptor, DopEcR, mediates the actions of both dopamine and ecdysone to control sex pheromone perception in an insect

    Directory of Open Access Journals (Sweden)

    Antoine eAbrieux

    2014-09-01

    Full Text Available Olfactory information mediating sexual behavior is crucial for reproduction in many animals, including insects. In male moths, the macroglomerular complex of the primary olfactory center, the antennal lobe (AL is specialized in the treatment of information on the female-emitted sex pheromone. Evidence is accumulating that modulation of behavioral pheromone responses occurs through neuronal plasticity via the action of hormones and/or catecholamines. We recently showed that a G-protein-coupled receptor (GPCR, AipsDopEcR, with its homologue known in Drosophila for its double affinity to the main insect steroid hormone 20-hydroxyecdysone (20E, and dopamine (DA, present in the ALs, is involved in the behavioral response to pheromone in the moth, Agrotis ipsilon. Here we tested the role of AipsDopEcR as compared to nuclear 20E receptors in central pheromone processing combining receptor inhibition with intracellular recordings of AL neurons. We show that the sensitivity of AL neurons for the pheromone in males decreases strongly after AipsDopEcR-dsRNA injection but also after inhibition of nuclear 20E receptors. Moreover we tested the involvement of 20E and DA in the receptor-mediated behavioral modulation in wind tunnel experiments, using ligand applications and receptor inhibition treatments. We show that both ligands are necessary and act on AipsDopEcR-mediated behavior. Altogether these results indicate that the GPCR membrane receptor, AipsDopEcR, controls sex pheromone perception through the action of both 20E and DA in the central nervous system, probably in concert with 20E action through nuclear receptors.

  13. Orchestrated Regulation of Nogo Receptors, Lotus, AMPA Receptors and BDNF in an ECT Model Suggests Opening and Closure of a Window of Synaptic Plasticity

    OpenAIRE

    Nordgren, Max; Karlsson, Tobias; Svensson, Maria; Koczy, Josefin; Josephson, Anna; Olson, Lars; Tingstroem, Anders; Brene, Stefan

    2013-01-01

    Electroconvulsive therapy (ECT) is an efficient and relatively fast acting treatment for depression. However, one severe side effect of the treatment is retrograde amnesia, which in certain cases can be long-term. The mechanisms behind the antidepressant effect and the amnesia are not well understood. We hypothesized that ECT causes transient downregulation of key molecules needed to stabilize synaptic structure and to prevent Ca2+ influx, and a simultaneous increase in neurotrophic factors, ...

  14. Role of adenosine A2A receptor signaling in the nicotine-evoked attenuation of reflex cardiac sympathetic control

    International Nuclear Information System (INIS)

    El-Mas, Mahmoud M.; El-gowilly, Sahar M.; Fouda, Mohamed A.; Saad, Evan I.

    2011-01-01

    Baroreflex dysfunction contributes to increased cardiovascular risk in cigarette smokers. Given the importance of adenosinergic pathways in baroreflex control, the hypothesis was tested that defective central adenosinergic modulation of cardiac autonomic activity mediates the nicotine-baroreflex interaction. Baroreflex curves relating changes in heart rate (HR) to increases or decreases in blood pressure (BP) evoked by i.v. doses (1-16 μg/kg) of phenylephrine (PE) and sodium nitroprusside (SNP), respectively, were constructed in conscious rats; slopes of the curves were taken as measures of baroreflex sensitivity (BRS). Nicotine (25 and 100 μg/kg i.v.) dose-dependently reduced BRS SNP in contrast to no effect on BRS PE . BRS SNP was also attenuated after intracisternal (i.c.) administration of nicotine. Similar reductions in BRS SNP were observed in rats pretreated with atropine or propranolol. The combined treatment with nicotine and atropine produced additive inhibitory effects on BRS, an effect that was not demonstrated upon concurrent exposure to nicotine and propranolol. BRS SNP was reduced in preparations treated with i.c. 8-phenyltheophylline (8-PT, nonselective adenosine receptor antagonist), 8-(3-Chlorostyryl) caffeine (CSC, A 2A antagonist), or VUF5574 (A 3 antagonist). In contrast, BRS SNP was preserved after blockade of A 1 (DPCPX) or A 2B (alloxazine) receptors or inhibition of adenosine uptake by dipyridamole. CSC or 8-PT abrogated the BRS SNP depressant effect of nicotine whereas other adenosinergic antagonists were without effect. Together, nicotine preferentially impairs reflex tachycardia via disruption of adenosine A 2A receptor-mediated facilitation of reflex cardiac sympathoexcitation. Clinically, the attenuation by nicotine of compensatory sympathoexcitation may be detrimental in conditions such as hypothalamic defense response, posture changes, and ventricular rhythms. - Research highlights: → The role of central adenosinergic sites in

  15. P2X7 receptor drives Th1 cell differentiation and controls the follicular helper T cell population to protect against Plasmodium chabaudi malaria.

    Directory of Open Access Journals (Sweden)

    Érika Machado de Salles

    2017-08-01

    Full Text Available A complete understanding of the mechanisms underlying the acquisition of protective immunity is crucial to improve vaccine strategies to eradicate malaria. However, it is still unclear whether recognition of damage signals influences the immune response to Plasmodium infection. Adenosine triphosphate (ATP accumulates in infected erythrocytes and is released into the extracellular milieu through ion channels in the erythrocyte membrane or upon erythrocyte rupture. The P2X7 receptor senses extracellular ATP and induces CD4 T cell activation and death. Here we show that P2X7 receptor promotes T helper 1 (Th1 cell differentiation to the detriment of follicular T helper (Tfh cells during blood-stage Plasmodium chabaudi malaria. The P2X7 receptor was activated in CD4 T cells following the rupture of infected erythrocytes and these cells became highly responsive to ATP during acute infection. Moreover, mice lacking the P2X7 receptor had increased susceptibility to infection, which correlated with impaired Th1 cell differentiation. Accordingly, IL-2 and IFNγ secretion, as well as T-bet expression, critically depended on P2X7 signaling in CD4 T cells. Additionally, P2X7 receptor controlled the splenic Tfh cell population in infected mice by promoting apoptotic-like cell death. Finally, the P2X7 receptor was required to generate a balanced Th1/Tfh cell population with an improved ability to transfer parasite protection to CD4-deficient mice. This study provides a new insight into malaria immunology by showing the importance of P2X7 receptor in controlling the fine-tuning between Th1 and Tfh cell differentiation during P. chabaudi infection and thus in disease outcome.

  16. Dopamine modulation of avoidance behavior in Caenorhabditis elegans requires the NMDA receptor NMR-1.

    Directory of Open Access Journals (Sweden)

    Melvin Baidya

    Full Text Available The nematode C. elegans utilizes a relatively simple neural circuit to mediate avoidance responses to noxious stimuli such as the volatile odorant octanol. This avoidance behavior is modulated by dopamine. cat-2 mutant animals that are deficient in dopamine biosynthesis have an increased response latency to octanol compared to wild type animals, and this defect can be fully restored with the application of exogenous dopamine. Because this avoidance behavior is mediated by glutamatergic signaling between sensory neurons and premotor interneurons, we investigated the genetic interactions between dopaminergic signaling and ionotropic glutamate receptors. cat-2 mutant animals lacking either the GLR-1 or GLR-2 AMPA/kainate receptors displayed an increased response latency to octanol, which could be restored via exogenous dopamine. However, whereas cat-2 mutant animals lacking the NMR-1 NMDA receptor had increased response latency to octanol they were insensitive to exogenous dopamine. Mutants that lacked both AMPA/kainate and NMDA receptors were also insensitive to exogenous dopamine. Our results indicate that dopamine modulation of octanol avoidance requires NMR-1, consistent with NMR-1 as a potential downstream signaling target for dopamine.

  17. Differences in the Control of Secondary Peristalsis in the Human Esophagus: Influence of the 5-HT4 Receptor versus the TRPV1 Receptor.

    Directory of Open Access Journals (Sweden)

    Chih-Hsun Yi

    Full Text Available Acute administration of 5-hydroxytryptamine4 (5-HT4 receptor agonist, mosapride or esophageal infusion of the transient receptor potential vanilloid receptor-1 (TRPV1 agonist capsaicin promotes secondary peristalsis. We aimed to investigate whether acute esophageal instillation of capsaicin-containing red pepper sauce or administration of mosapride has different effects on the physiological characteristics of secondary peristalsis.Secondary peristalsis was induced with mid-esophageal air injections in 14 healthy subjects. We compared the effects on secondary peristalsis subsequent to capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg or 40 mg oral mosapride.The threshold volume for generating secondary peristalsis during slow air distensions was significantly decreased with capsaicin infusion compared to mosapride (11.6 ± 1.0 vs. 14.1 ± 0.8 mL, P = 0.02. The threshold volume required to produce secondary peristalsis during rapid air distension was also significantly decreased with capsaicin infusion (4.6 ± 0.5 vs. 5.2 ± 0.6 mL, P = 0.02. Secondary peristalsis was noted more frequently in response to rapid air distension after capsaicin infusion than mosapride (80% [60-100%] vs. 65% [5-100%], P = 0.04. Infusion of capsaicin or mosapride administration didn't change any parameters of primary or secondary peristalsis.Esophageal infusion with capsaicin-containing red pepper sauce suspension does create greater mechanosensitivity as measured by secondary peristalsis than 5-HT4 receptor agonist mosapride. Capsaicin-sensitive afferents appear to be more involved in the sensory modulation of distension-induced secondary peristalsis.

  18. The progesterone receptor antagonist, onapristone has differential effects on the timing and control of the luteolytic mechanism depending on timing of administration in sheep.

    Science.gov (United States)

    Mann, G E; Wathes, D C; Robinson, R S

    2013-08-25

    Cyclic ewes were treated with control vehicle or progesterone receptor antagonist (onapristone; 100mg i.m. twice daily) during either early (day 3-5) or late (day 12-14) luteal phase and plasma samples collected for hormone analysis and to determine endogenous and oxytocin induced PGF2α release. On day 14 and 17, ewes were euthanised and reproductive tracts collected for ovarian morphology and endometrium for oxytoxin and steroid hormone receptor analysis. Early treatment increased LH, but not progesterone or oestradiol, while late treatment elevated all three hormones. Early treatment delayed the up-regulation of endometrial oxytocin receptors and responsiveness to oxytocin challenge, delaying luteolysis. Late treatment advanced development of oxytocin receptors and responsiveness to oxytocin though not timing of luteolysis. Patterns of hormone receptor mRNA were differentially disrupted by treatments. Results provide mechanistic insight into hormonal control of the oestrous cycle and identify the ability of the luteolytic mechanism to dissociate from functional luteolysis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  19. The distribution of cerebral muscarinic acetylcholine receptors in vivo in patients with dementia. A controlled study with 123IQNB and single photon emission computed tomography

    International Nuclear Information System (INIS)

    Weinberger, D.R.; Gibson, R.; Coppola, R.; Jones, D.W.; Molchan, S.; Sunderland, T.; Berman, K.F.; Reba, R.C.

    1991-01-01

    A high-affinity muscarinic receptor antagonist, 123IQNB (3-quinuclidinyl-4-iodobenzilate labeled with iodine 123), was used with single photon emission computed tomography to image muscarinic acetylcholine receptors in 14 patients with dementia and in 11 healthy controls. High-resolution single photon emission computed tomographic scanning was performed 21 hours after the intravenous administration of approximately 5 mCi of IQNB. In normal subjects, the images of retained ligand showed a consistent regional pattern that correlated with postmortem studies of the relative distribution of muscarinic receptors in the normal human brain, having high radioactivity counts in the basal ganglia, occipital cortex, and insular cortex, low counts in the thalamus, and virtually no counts in the cerebellum. Eight of 12 patients with a clinical diagnosis of Alzheimer's disease had obvious focal cortical defects in either frontal or posterior temporal cortex. Both patients with a clinical diagnosis of Pick's disease had obvious frontal and anterior temporal defects. A region of interest statistical analysis of relative regional activity revealed a significant reduction bilaterally in the posterior temporal cortex of the patients with Alzheimer's disease compared with controls. This study demonstrates the practicability of acetylcholine receptor imaging with 123IQNB and single photon emission computed tomography. The data suggest that focal abnormalities in muscarinic binding in vivo may characterize some patients with Alzheimer's disease and Pick's disease, but further studies are needed to address questions about partial volume artifacts and receptor quantification

  20. Control of blood pressure, appetite, and glucose by leptin in mice lacking leptin receptors in proopiomelanocortin neurons.

    Science.gov (United States)

    do Carmo, Jussara M; da Silva, Alexandre A; Cai, Zhengwei; Lin, Shuying; Dubinion, John H; Hall, John E

    2011-05-01

    Although the central nervous system melanocortin system is an important regulator of energy balance, the role of proopiomelanocortin (POMC) neurons in mediating the chronic effects of leptin on appetite, blood pressure, and glucose regulation is unknown. Using Cre/loxP technology we tested whether leptin receptor deletion in POMC neurons (LepR(flox/flox)/POMC-Cre mice) attenuates the chronic effects of leptin to increase mean arterial pressure (MAP), enhance glucose use and oxygen consumption, and reduce appetite. LepR(flox/flox)/POMC-Cre, wild-type, LepR(flox/flox), and POMC-Cre mice were instrumented for MAP and heart rate measurement by telemetry and venous catheters for infusions. LepR(flox/flox)/POMC-Cre mice were heavier, hyperglycemic, hyperinsulinemic, and hyperleptinemic compared with wild-type, LepR(flox/flox), and POMC-Cre mice. Despite exhibiting features of metabolic syndrome, LepR(flox/flox)/POMC-Cre mice had normal MAP and heart rate compared with LepR(flox/flox) but lower MAP and heart rate compared with wild-type mice. After a 5-day control period, leptin was infused (2 μg/kg per minute, IV) for 7 days. In control mice, leptin increased MAP by ≈5 mm Hg despite decreasing food intake by ≈35%. In contrast, leptin infusion in LepR(flox/flox)/POMC-Cre mice reduced MAP by ≈3 mm Hg and food intake by ≈28%. Leptin significantly decreased insulin and glucose levels in control mice but not in LepR(flox/flox)/POMC-Cre mice. Leptin increased oxygen consumption in LepR(flox/flox)/POMC-Cre and wild-type mice. Activation of POMC neurons is necessary for the chronic effects of leptin to raise MAP and reduce insulin and glucose levels, whereas leptin receptors in other areas of the brain other than POMC neurons appear to play a key role in mediating the chronic effects of leptin on appetite and oxygen consumption.

  1. A randomized controlled trial of the efficacy and safety of CCX282-B, an orally-administered blocker of chemokine receptor CCR9, for patients with Crohn's disease

    DEFF Research Database (Denmark)

    Keshav, Satish; Vaňásek, Tomáš; Niv, Yaron

    2013-01-01

    CCX282-B, also called vercirnon, is a specific, orally-administered chemokine receptor CCR9 antagonist that regulates migration and activation of inflammatory cells in the intestine. This randomized, placebo-controlled trial was conducted to evaluate the safety and efficacy of CCX282-B in 436...

  2. Epidermal growth factor receptor-induced activato protein 1 activity controls density-dependent growht inhibition in normal rat kidney fibroblasts.

    NARCIS (Netherlands)

    Hornberg, J.J.; Dekker, H.; Peters, P.H.J.; Langerak, P.; Westerhoff, H.V.; Lankelma, J.; Zoelen, E.J.J.

    2006-01-01

    Density-dependent growth inhibition secures tissue homeostasis. Dysfunction of the mechanisms, which regulate this type of growth control is a major cause of neoplasia. In confluent normal rat kidney (NRK) fibroblasts, epidermal growth factor (EGF) receptor levels decline, ultimately rendering these

  3. The gene encoding the melanin-concentrating hormone receptor 1 is associated with schizophrenia in a Danish case-control sample

    DEFF Research Database (Denmark)

    Demontis, Ditte; Nyegaard, Mette; Christensen, Jane H

    2012-01-01

    OBJECTIVE: The MCHR1 gene encoding the melanin-concentrating hormone receptor 1 is located on chromosome 22q13.2 and has previously been associated with schizophrenia in a study of cases and controls from the Faroe Islands and Scotland. Herein we report an association between variations in the MCHR...

  4. Heart rate acceleration with GLP-1 receptor agonists in type 2 diabetes patients : an acute and 12-week randomised, double-blind, placebo-controlled trial

    NARCIS (Netherlands)

    Smits, Mark M; Tonneijck, Lennart; Muskiet, Marcel H A; Hoekstra, T.; Kramer, Mark H H; Diamant, Michaela; van Raalte, Daniël H

    OBJECTIVE: To examine mechanisms underlying resting heart rate (RHR) increments of GLP-1 receptor agonists in type 2 diabetes patients. DESIGN: Acute and 12-week randomised, placebo-controlled, double-blind, single-centre, parallel-group trial. METHODS: In total, 57 type 2 diabetes patients

  5. RECOMBINANT HUMAN INTERLEUKIN-1 RECEPTOR ANTAGONIST IN THE TREATMENT OF PATIENTS WITH SEPSIS SYNDROME - RESULTS FROM A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL

    NARCIS (Netherlands)

    FISHER, C. J.; DHAINAUT, J. F. A.; Opal, S. M.; Pribble, J. P.; BALK, R. A.; SLOTMAN, G. J.; IBERTI, T. J.; RACKOW, E. C.; SHAPIRO, M. J.; GREENMAN, R. L.; REINES, H. D.; SHELLY, M. P.; THOMPSON, B. W.; LABRECQUE, J. F.; Catalano, M. A.; KNAUS, W. A.; Sadoff, J. C.; ASTIZ, M.; CARPATI, C.; BONE, R. C.; FREIDMAN, B.; MURE, A. J.; BRATHWAITE, C.; SHAPIRO, E.; MELHORN, L.; TAYLOR, R.; KEEGAN, M.; OBRIEN, J.; SCHEIN, R.; PENA, M.; WASSERLOUF, M.; OROPELLO, J.; BENJAMIN, E.; DELGUIDICE, R.; EMMANUEL, G.; LIE, T.; Anderson, L.; Marshall, J.; DEMAJO, W.; ROTSTEIN, O.; FOSTER, D.; Abraham, E.; MIDDLETON, H.; Perry, C.; LEVY, H.; FRY, D. E.; SIMPSON, S. Q.; CROWELL, R. E.; Neidhart, M.; Stevens, D.; COFFMAN, T.; NARASIMHAM, N.; MERRICK, D. K.; BERGQUIST, W.; MATZEL, K. E.; HUEBLER, M.; Foulke, G. E.; ALBERTSON, T. E.; WALBY, W. F.; ALLEN, R. P.; Baughman, R.; HASSELGREN, P. O.; Fink, M. P.; FAVORITO, F.; THOMPSON, B. T.; CORBIN, R.; SHELLHORSE, G. Y.; FRAZIER, A.; White, S.; GARRARD, C.; ACOURT, C.; STORER, S.; GERVICH, D. H.; FOSHE, D.; BRASE, R.; BAGDAHN, A.; COONEY, R.; Smith, J. S.; MARTIN, L. F.; Vincent, J. L.; Friedman, G.; Berlot, G.; FLETCHER, J. R.; WILLIAMS, M. D.; WRIGHT, T. F.; Johnson, S.; FEILD, C.; WOLF, K.; MACINTYRE, N.; DUBIN, H. G.; DURKIN, M. R.; DUBIN, P. K.; STAUBACH, K. H.; FEIN, A. M.; SCHULMAN, D. B.; NIEDERMAN, M. S.; CHALFIN, D. B.; van Leeuwen, P. A. M.; Boermeester, M. A.; Schneider, A. J.; BANDER, J.; IMM, A.; BERNARD, G.; Nelson, L.; Stroud, M.; SAFCSAK, K.; CERRA, F.; RINDAL, J.; Mann, H.; HALPERN, N.; SILVERSTEIN, J.; ALICEA, M.; Sibbald, W. J.; MARTIN, C. M.; RUTLEDGE, F. S.; PETTI, K.; RUSSELL, J. A.; KRUGER, R.; DRUMMOND, A.; LANGE, P.; SEIFERT, T.; DUROCHER, A.; TENAILLON, A.; BOITEAU, R.; LHERM, T.; Lowry, S. F.; Coyle, S. M.; Barie, P. S.; DEMARIA, E.; SNYDMAN, D. R.; SCHWAITZBERG, S. D.; NASRAWAY, S. A.; GRINDLINGER, J.; SUMMER, W.; DEBOISBLANC, B.; WAHL, M.; ALESTIG, K.; GROSSMAN, J.; MAKI, D.; PAZ, H. L.; Weiner, M.; BIHARI, D.; Campbell, D.; BLEICHNER, G.; DAHN, M. S.; LANGE, M. P. A.; Hall, J.; POHLMAN, A.; WENZEL, R. P.; GROSSERODE, M.; COSTIGAN, M.; MILESKI, W.; WEIGELT, J.; YESTON, N.; IRIZARRY, C.; Ross, J.; ROBBINS, J.; NIGHTINGALE, P.; OWEN, K.; SANDSTEDT, S.; Berg, S.; SIMON, G. L.; SENEFF, M. G.; CONRY, K. M.; ZIMMERMAN, J. L.; Dellinger, R. P.; Johnston, R.; ALLEE, P.; GRANDE, P. O.; MYHRE, E.; DHAINAUT, J. F.; HAMY, I.; Mira, J. P.; HARMON, J.; White, J.; MCKIE, L.; SILVERMAN, H.; TUMA, P.; Bennett, D.; PORTER, J. C.; LAURELL, M. H.; Jacobs, S.; ASH, S.; Stiles, D. M.; PRIOR, M. J.; KNATTERUD, G.; TERRIN, M.; KUFERA, J.; WILKENS, P.; RA, K.; MONROE, L.; SPRUNG, C.; HAMILTON, C. M.; MATTHAY, R.; MCCABE, W.; TONASCIA, J.; WIEDEMAN, H.; Wittes, J.; CAMPION, G. V.; CROFT, C. R.; LUSTICK, R.; LOOKABAUGH, J.; GORDON, G. S.; NOE, L.; BLOEDOW, D.; SMITH, C. G.; BRANNON, D.; KUSH, R.; NG, D.; MOORE, E.; BAZEMORE, K.; GALVAN, M.; Wagner, D.; HARRELL, F.; STABLEIN, D.

    1994-01-01

    Objective.-To further define the safety and efficacy of recombinant human interleukin 1 receptor antagonist (rhlL-1ra) in the treatment of sepsis syndrome. Study Design.-Randomized, double-blind, placebo-controlled, multicenter, multinational clinical trial. Population.-A total of 893 patients with

  6. The autonomic nervous system and cardiac GLP-1 receptors control heart rate in mice

    Directory of Open Access Journals (Sweden)

    Laurie L. Baggio

    2017-11-01

    Conclusions: GLP-1R agonists increase HR through multiple mechanisms, including regulation of autonomic nervous system function, and activation of the atrial GLP-1R. Surprisingly, the isolated atrial GLP-1R does not transduce a direct chronotropic effect following exposure to GLP-1R agonists in the intact heart, or isolated atrium, ex vivo. Hence, cardiac GLP-1R circuits controlling HR require neural inputs and do not function in a heart-autonomous manner.

  7. Low serum vitamin D levels and anti-N-methyl-d-aspartate receptor encephalitis: A case-control study.

    Science.gov (United States)

    Shu, Yaqing; Su, Qingmei; Liao, Siyuan; Lu, Tingting; Li, Rui; Sun, Xiaobo; Qiu, Wei; Yang, Yu; Hu, Xueqiang; Lu, Zhengqi

    2017-01-01

    Low vitamin D levels are associated with autoimmunity, but the relationship with anti-N-Methyl-d-aspartate receptor (anti-NMDAR) encephalitis is unknown. 25(OH) D levels and clinical and cerebrospinal fluid parameters were evaluated in 30 patients with anti-NMDAR encephalitis and compared with 90 age-, sex-, and season-matched healthy controls. 25(OH)D levels were lower in patients with anti-NMDAR encephalitis compared to controls (43.89 ± 17.91 vs 64.24 ± 24.38 nmol/L, p  30 years, p = 0.002), severe impairment (mRS ≥ 5) (vs mRS D levels were associated with age (r = 0.393, p = 0.032), and mRS (r = -0.417, p = 0.022). Our data showed that serum 25(OH)D levels were reduced in patients with anti-NMDAR encephalitis. Copyright © 2016. Published by Elsevier Ltd.

  8. Toll-Like Receptors 2 and 4 Cooperate in the Control of the Emerging Pathogen Brucella microti.

    Science.gov (United States)

    Arias, Maykel A; Santiago, Llipsy; Costas-Ramon, Santiago; Jaime-Sánchez, Paula; Freudenberg, Marina; Jiménez De Bagüés, Maria P; Pardo, Julián

    2016-01-01

    Toll-like receptors (TLRs) recognize pathogen-derived molecules and play a critical role during the host innate and adaptive immune response. Brucella spp. are intracellular gram-negative bacteria including several virulent species, which cause a chronic zoonotic infection in a wide range of mammalian hosts known as brucellosis. A new Brucella species, Brucella microti , was recently isolated from wild rodents and found to be highly pathogenic in mice. Using this species-specific model, it was previously found that CD8 + T cells are required to control this infection. In order to find out the role of TLR-mediated responses in the control of this pathogen, the course of infection of B. microti was analyzed over 3 weeks in wild-type (WT) and TLR knock out (KO) mice including TLR2 -/- , TLR4 -/- , TLR9 -/- , TLR2×4 -/- and TLR2×4×9 -/- . WT and single TLR2, TLR4 and TLR9 KO mice similarly control infection in liver and spleen. In contrast, bacterial clearance was delayed in TLR2×4 -/- and TLR2×4×9 -/- mice at 7 and 14 days post-infection. This defect correlated with impaired maturation and pro-inflammatory cytokine production in B. microti -infected dendritic cells from TLR2×4 -/- and TLR2×4×9 -/- mice. Finally, it was found that Tc cells from TLR2×4 -/- and TLR2×4×9 -/- mice showed reduced ability to inhibit growth of B. microti in macrophages, suggesting the involvement of TLR2 and 4 in the generation of specific Tc cells. Our findings indicate that TLR2 and TLR4 are required to control B. microti infection in mice and that this effect could be related to its participation in the maturation of dendritic cells and the generation of specific CD8 + Tc cells.

  9. (S)-2-Amino-3-(3-hydroxy-7,8-dihydro-6H-cyclohepta[d]isoxazol-4-yl)propionic acid, a potent and selective agonist at the GluR5 subtype of ionotropic glutamate receptors. Synthesis, modeling, and molecular pharmacology

    DEFF Research Database (Denmark)

    Brehm, Lotte; Greenwood, Jeremy R; Hansen, Kasper B

    2003-01-01

    )propionic acid (AMPA) but inactive at NMDA receptors. However, 4-AHCP was found to be much weaker than AMPA as an inhibitor of [(3)H]AMPA binding and to have limited effect in a [(3)H]kainic acid binding assay using rat cortical membranes. To shed light on the mechanism(s) underlying this quite enigmatic......, activated cloned AMPA receptor subunits GluR1o, GluR3o, and GluR4o with EC(50) values in the range 4.5-15 microM and the coexpressed kainate-preferring subunits GluR6 + KA2 (EC(50) = 6.4 microM). Compound 6, but not 7, proved to be a very potent agonist (EC(50) = 0.13 microM) at the kainate-preferring GluR5...... subunit, equipotent with (S)-2-amino-3-(5-tert-butyl-3-hydroxyisothiazol-4-yl)propionic acid [(S)-Thio-ATPA, 4] and almost 4 times more potent than (S)-2-amino-3-(5-tert-butyl-3-hydroxyisoxazol-4-yl)propionic acid [(S)-ATPA, 3]. Compound 6 thus represents a new structural class of GluR5 agonists...

  10. Enhanced Androgen Signaling with Androgen Receptor Overexpression in the Osteoblast Lineage Controls Skeletal Turnover, Matrix Quality and Bone Architecture

    Science.gov (United States)

    2009-12-01

    Fu , M. , and Pestell , R. ( 2006 ). Epigenetic regulation of nuclear steroid receptors . Biochem. Pharmacol. 72 , 1589 – 1596...2006;38:1289–1297. 21. Leader J, Wang C, Fu M, Pestell R. Epigenetic regulation of nuclear steroid receptors. Biochem Pharmacol 2006;72:1589–1596. 22...Nat Genet 2006;38:1289-97. 21. Leader J, Wang C, Fu M, Pestell R. Epigenetic regulation of nuclear steroid receptors. Biochem Pharmacol 2006;72

  11. PCA3 noncoding RNA is involved in the control of prostate-cancer cell survival and modulates androgen receptor signaling

    International Nuclear Information System (INIS)

    Ferreira, Luciana Bueno; Gimba, Etel Rodrigues Pereira; Palumbo, Antonio; Mello, Kivvi Duarte de; Sternberg, Cinthya; Caetano, Mauricio S; Oliveira, Felipe Leite de; Neves, Adriana Freitas; Nasciutti, Luiz Eurico; Goulart, Luiz Ricardo

    2012-01-01

    PCA3 is a non-coding RNA (ncRNA) that is highly expressed in prostate cancer (PCa) cells, but its functional role is unknown. To investigate its putative function in PCa biology, we used gene expression knockdown by small interference RNA, and also analyzed its involvement in androgen receptor (AR) signaling. LNCaP and PC3 cells were used as in vitro models for these functional assays, and three different siRNA sequences were specifically designed to target PCA3 exon 4. Transfected cells were analyzed by real-time qRT-PCR and cell growth, viability, and apoptosis assays. Associations between PCA3 and the androgen-receptor (AR) signaling pathway were investigated by treating LNCaP cells with 100 nM dihydrotestosterone (DHT) and with its antagonist (flutamide), and analyzing the expression of some AR-modulated genes (TMPRSS2, NDRG1, GREB1, PSA, AR, FGF8, CdK1, CdK2 and PMEPA1). PCA3 expression levels were investigated in different cell compartments by using differential centrifugation and qRT-PCR. LNCaP siPCA3-transfected cells significantly inhibited cell growth and viability, and increased the proportion of cells in the sub G0/G1 phase of the cell cycle and the percentage of pyknotic nuclei, compared to those transfected with scramble siRNA (siSCr)-transfected cells. DHT-treated LNCaP cells induced a significant upregulation of PCA3 expression, which was reversed by flutamide. In siPCA3/LNCaP-transfected cells, the expression of AR target genes was downregulated compared to siSCr-transfected cells. The siPCA3 transfection also counteracted DHT stimulatory effects on the AR signaling cascade, significantly downregulating expression of the AR target gene. Analysis of PCA3 expression in different cell compartments provided evidence that the main functional roles of PCA3 occur in the nuclei and microsomal cell fractions. Our findings suggest that the ncRNA PCA3 is involved in the control of PCa cell survival, in part through modulating AR signaling, which may raise new

  12. Alterations in the steroid hormone receptor co-chaperone FKBPL are associated with male infertility: a case-control study

    LENUS (Irish Health Repository)

    Sunnotel, Olaf

    2010-03-08

    Abstract Background Male infertility is a common cause of reproductive failure in humans. In mice, targeted deletions of the genes coding for FKBP6 or FKBP52, members of the FK506 binding protein family, can result in male infertility. In the case of FKBP52, this reflects an important role in potentiating Androgen Receptor (AR) signalling in the prostate and accessory glands, but not the testis. In infertile men, no mutations of FKBP52 or FKBP6 have been found so far, but the gene for FKBP-like (FKBPL) maps to chromosome 6p21.3, an area linked to azoospermia in a group of Japanese patients. Methods To determine whether mutations in FKBPL could contribute to the azoospermic phenotype, we examined expression in mouse and human tissues by RNA array blot, RT-PCR and immunohistochemistry and sequenced the complete gene from two azoospermic patient cohorts and matching control groups. FKBPL-AR interaction was assayed using reporter constructs in vitro. Results FKBPL is strongly expressed in mouse testis, with expression upregulated at puberty. The protein is expressed in human testis in a pattern similar to FKBP52 and also enhanced AR transcriptional activity in reporter assays. We examined sixty patients from the Japanese patient group and found one inactivating mutation and one coding change, as well as a number of non-coding changes, all absent in fifty-six controls. A second, Irish patient cohort of thirty showed another two coding changes not present in thirty proven fertile controls. Conclusions Our results describe the first alterations in the gene for FKBPL in azoospermic patients and indicate a potential role in AR-mediated signalling in the testis.

  13. Alterations in the steroid hormone receptor co-chaperone FKBPL are associated with male infertility: a case-control study

    Directory of Open Access Journals (Sweden)

    Barton David

    2010-03-01

    Full Text Available Abstract Background Male infertility is a common cause of reproductive failure in humans. In mice, targeted deletions of the genes coding for FKBP6 or FKBP52, members of the FK506 binding protein family, can result in male infertility. In the case of FKBP52, this reflects an important role in potentiating Androgen Receptor (AR signalling in the prostate and accessory glands, but not the testis. In infertile men, no mutations of FKBP52 or FKBP6 have been found so far, but the gene for FKBP-like (FKBPL maps to chromosome 6p21.3, an area linked to azoospermia in a group of Japanese patients. Methods To determine whether mutations in FKBPL could contribute to the azoospermic phenotype, we examined expression in mouse and human tissues by RNA array blot, RT-PCR and immunohistochemistry and sequenced the complete gene from two azoospermic patient cohorts and matching control groups. FKBPL-AR interaction was assayed using reporter constructs in vitro. Results FKBPL is strongly expressed in mouse testis, with expression upregulated at puberty. The protein is expressed in human testis in a pattern similar to FKBP52 and also enhanced AR transcriptional activity in reporter assays. We examined sixty patients from the Japanese patient group and found one inactivating mutation and one coding change, as well as a number of non-coding changes, all absent in fifty-six controls. A second, Irish patient cohort of thirty showed another two coding changes not present in thirty proven fertile controls. Conclusions Our results describe the first alterations in the gene for FKBPL in azoospermic patients and indicate a potential role in AR-mediated signalling in the testis.

  14. Genetic analysis of the vitamin D receptor gene in two epithelial cancers: melanoma and breast cancer case-control studies

    International Nuclear Information System (INIS)

    Barroso, Eva; Arias, Jose I; Zamora, Pilar; Blanco, Monserrat; Lazaro, Pablo; Benitez, Javier; Ribas, Gloria; Fernandez, Lara P; Milne, Roger L; Pita, Guillermo; Sendagorta, Elena; Floristan, Uxua; Feito, Marta; Aviles, Jose A; Martin-Gonzalez, Manuel

    2008-01-01

    Vitamin D serum levels have been found to be related to sun exposure and diet, together with cell differentiation, growth control and consequently, cancer risk. Vitamin D receptor (VDR) genotypes may influence cancer risk; however, no epidemiological studies in sporadic breast cancer (BC) or malignant melanoma (MM) have been performed in a southern European population. In this study, the VDR gene has been evaluated in two epithelial cancers BC and MM. We have conducted an analysis in 549 consecutive and non-related sporadic BC cases and 556 controls, all from the Spanish population, and 283 MM cases and 245 controls. Genotyping analyses were carried out on four putatively functional SNPs within the VDR gene. An association with the minor allele A of the non-synonymous SNP rs2228570 (rs10735810, FokI, Met1Thr) was observed for BC, with an estimated odds ratio (OR) of 1.26 (95% CI = 1.02–1.57; p = 0.036). The synonymous variant rs731236 (TaqI) appeared to be associated with protection from BC (OR = 0.80, 95%CI = 0.64–0.99; p = 0.047). No statistically significant associations with MM were observed for any SNP. Nevertheless, sub-group analyses revealed an association between rs2228570 (FokI) and absence of childhood sunburns (OR = 0.65, p = 0.003), between the 3'utr SNP rs739837 (BglI) and fair skin (OR = 1.31, p = 0.048), and between the promoter SNP rs4516035 and the more aggressive tumour location in head-neck and trunk (OR = 1.54, p = 0.020). In summary, we observed associations between SNPs in the VDR gene and BC risk, and a comprehensive analysis using clinical and tumour characteristics as outcome variables has revealed potential associations with MM. These associations required confirmation in independent studies

  15. Tumor necrosis factor (TNF) receptor shedding controls thresholds of innate immune activation that balance opposing TNF functions in infectious and inflammatory diseases

    DEFF Research Database (Denmark)

    Xanthoulea, Sofia; Pasparakis, Manolis; Kousteni, Stavroula

    2004-01-01

    Tumor necrosis factor (TNF) is a potent cytokine exerting critical functions in the activation and regulation of immune and inflammatory responses. Due to its pleiotropic activities, the amplitude and duration of TNF function must be tightly regulated. One of the mechanisms that may have evolved...... to modulate TNF function is the proteolytic cleavage of its cell surface receptors. In humans, mutations affecting shedding of the p55TNF receptor (R) have been linked with the development of the TNFR-associated periodic syndromes, disorders characterized by recurrent fever attacks and localized inflammation....... Here we show that knock-in mice expressing a mutated nonsheddable p55TNFR develop Toll-like receptor-dependent innate immune hyperreactivity, which renders their immune system more efficient at controlling intracellular bacterial infections. Notably, gain of function for antibacterial host defenses...

  16. Significance of ACTH4-10 in the control of hippocampal corticosterone receptor capacity of hypophysectomized rats

    NARCIS (Netherlands)

    Veldhuis, H D; De Kloet, E R

    1982-01-01

    The effect of hypophysectomy on the number of corticosterone receptor sites was investigated in three rat brain regions and was compared with the effect of long-term adrenalectomy. Subsequently, the effect on receptor capacity was measured after the hypophysectomized rats had received as

  17. Glutamatergic induction of CREB phosphorylation and Fos expression in primary cultures of the suprachiasmatic hypothalamus in vitro is mediated by co-ordinate activity of NMDA and non-NMDA receptors.

    Science.gov (United States)

    Schurov, I L; McNulty, S; Best, J D; Sloper, P J; Hastings, M H

    1999-01-01

    Exposure of Syrian hamsters to light 1 h after lights-off rapidly (10 min) induced nuclear immunoreactivity (-ir) to the phospho-Ser133 form of the Ca2+/cAMP response element (CRE) binding protein (pCREB) in the retinorecipient zone of the suprachiasmatic nuclei (SCN). Light also induced nuclear Fos-ir in the same region of the SCN after 1 h. The glutamatergic N-methyl-D-aspartate (NMDA) receptor blocker MK801 attenuated the photic induction of both factors. To investigate glutamatergic regulation of pCREB and Fos further, tissue blocks and primary cultures of neonatal hamster SCN were examined by Western blotting and immunocytochemistry in vitro. On Western blots of SCN tissue, the pCREB-ir signal at 45 kDa was enhanced by glutamate or a mixture of glutamatergic agonists (NMDA, amino-methyl proprionic acid (AMPA), and Kainate (KA)), whereas total CREB did not change. Glutamate or the mixture of agonists also induced a 56 kDa band identified as Fos protein in SCN tissue. In dissociated cultures of SCN, glutamate caused a rapid (15 min) induction of nuclear pCREB-ir and Fos-ir (after 60 min) exclusively in neurones, both GABA-ir and others. Treatment with NMDA alone had no effect on pCREB-ir. AMPA alone caused a slight increase in pCREB-ir. However, kainate alone or in combination with NMDA and AMPA induced nuclear pCREB-ir equal to that induced by glutamate. The effects of glutamate on pCREB-ir and Fos-ir were blocked by antagonists of both NMDA (MK801) and AMPA/KA (NBQX) receptors. In the absence of extracellular Mg2+, MK801 blocked glutamatergic induction of Fos-ir. However, the AMPA/KA receptor antagonist was no longer effective at blocking glutamatergic induction of either Fos-ir or pCREB-ir, consistent with the model that glutamate regulates gene expression in the SCN by a co-ordinate action through both NMDA and AMPA/KA receptors. Glutamatergic induction of nuclear pCREB-ir in GABA-ir neurones was blocked by KN-62 an inhibitor of Ca2+/Calmodulin (Ca

  18. Autonomous control of phosphatidylinositol turnover by histamine and acetylcholine receptors in the NIE-115 neuron-like cell line

    International Nuclear Information System (INIS)

    Large, T.H.; Lambert, M.P.; Cohen, N.M.; Klein, W.L.

    1986-01-01

    Histamine was found to stimulate the turnover of phosphatidylinositol (PI) in cultures of neuron-like NE-115 cells. Turnover was measured by increased production of ( 3 H)inositol phosphates (breakdown) and by accelerated incorporation of 32 P into PI (resynthesis). Data were consistent with hydrolysis of polyphosphoinositides being the initial event in receptor-stimulated PI turnover. This response to histamine desensitized within 10 min. Receptor systems for histamine and acetylcholine were tested for possible interactions: PI turnover in response to dual stimulation was approximately equal to the sum of the individual responses while prior desensitization of the acetylcholine receptor system had no effect on subsequent stimulation of the histamine receptor system. These results are consistent with the hypothesis that components of acetylcholine and histamine receptor systems responsible for PI turnover are autonomously organised and regulated. (author)

  19. Sexual dimorphism in the volume of song control nuclei in European starlings: assessment by a Nissl stain and autoradiography for muscarinic cholinergic receptors.

    Science.gov (United States)

    Bernard, D J; Casto, J M; Ball, G F

    1993-08-22

    Previous studies have found that the volume of several song control nuclei is larger in male songbirds than in female songbirds. The degree of this volumetric sex difference within a given species appears to be systematically related to the degree of the behavioral sex difference. The largest volumetric differences have been reported in species in which the male sings and the female sings little, if at all, and the smallest sex differences in volume have been reported in species in which males and females both sing in nearly equal amounts. We compared the volume of three song control nuclei in male and female European starlings (Sturnus vulgaris), a species in which females are known to sing, though at a much lower rate than males. We investigated the volume of hyperstriatum ventrale, pars caudale, nucleus robustus archistriatalis, and area X of the lobus parolfactorius as defined with the use of a Nissl stain. In addition, we measured the volume of area X as defined by the density of muscarinic cholinergic receptors visualized by in vitro receptor autoradiographic methods. The volumes of all three of the song nuclei, as defined by Nissl staining, are significantly larger in males than in females. For area X, Nissl staining and receptor autoradiography indicate the same significant volumetric sex difference. The three nuclei are approximately one and one half to two times larger in males than in females, a degree of dimorphism that is intermediate to those reported for other species. Previous investigations of sex differences in the avian vocal control system have used only Nissl stains to define nuclear volumes. We demonstrate in this paper that receptor autoradiography can be used to assess dimorphisms in nuclear volume. Broad application of this approach to a number of neurotransmitter receptor systems will better characterize the dimorphisms in the song system, and therefore will provide greater insight into the neuroanatomical and neurochemical control of

  20. A Novel Mechanism of Androgen Receptor Action

    National Research Council Canada - National Science Library

    Roberts, Jr, Charles T

    2006-01-01

    .... Specifically, the authors had determined that the androgen receptor controls the expression of the cell-surface receptor for the hormone IGF-1 at the level of translation of the IGF-1 receptor mRNA...

  1. Artery Tertiary Lymphoid Organs Control Aorta Immunity and Protect against Atherosclerosis via Vascular Smooth Muscle Cell Lymphotoxin β Receptors

    Science.gov (United States)

    Hu, Desheng; Mohanta, Sarajo K.; Yin, Changjun; Peng, Li; Ma, Zhe; Srikakulapu, Prasad; Grassia, Gianluca; MacRitchie, Neil; Dever, Gary; Gordon, Peter; Burton, Francis L.; Ialenti, Armando; Sabir, Suleman R.; McInnes, Iain B.; Brewer, James M.; Garside, Paul; Weber, Christian; Lehmann, Thomas; Teupser, Daniel; Habenicht, Livia; Beer, Michael; Grabner, Rolf; Maffia, Pasquale; Weih, Falk; Habenicht, Andreas J.R.

    2015-01-01

    Summary Tertiary lymphoid organs (TLOs) emerge during nonresolving peripheral inflammation, but their impact on disease progression remains unknown. We have found in aged Apoe−/− mice that artery TLOs (ATLOs) controlled highly territorialized aorta T cell responses. ATLOs promoted T cell recruitment, primed CD4+ T cells, generated CD4+, CD8+, T regulatory (Treg) effector and central memory cells, converted naive CD4+ T cells into induced Treg cells, and presented antigen by an unusual set of dendritic cells and B cells. Meanwhile, vascular smooth muscle cell lymphotoxin β receptors (VSMC-LTβRs) protected against atherosclerosis by maintaining structure, cellularity, and size of ATLOs though VSMC-LTβRs did not affect secondary lymphoid organs: Atherosclerosis was markedly exacerbated in Apoe−/−Ltbr−/− and to a similar extent in aged Apoe−/−Ltbrfl/flTagln-cre mice. These data support the conclusion that the immune system employs ATLOs to organize aorta T cell homeostasis during aging and that VSMC-LTβRs participate in atherosclerosis protection via ATLOs. PMID:26084025

  2. Lithocholic acid controls adaptive immune responses by inhibition of Th1 activation through the Vitamin D receptor.

    Science.gov (United States)

    Pols, Thijs W H; Puchner, Teresa; Korkmaz, H Inci; Vos, Mariska; Soeters, Maarten R; de Vries, Carlie J M

    2017-01-01

    Bile acids are established signaling molecules next to their role in the intestinal emulsification and uptake of lipids. We here aimed to identify a potential interaction between bile acids and CD4+ Th cells, which are central in adaptive immune responses. We screened distinct bile acid species for their potency to affect T cell function. Primary human and mouse CD4+ Th cells as well as Jurkat T cells were used to gain insight into the mechanism underlying these effects. We found that unconjugated lithocholic acid (LCA) impedes Th1 activation as measured by i) decreased production of the Th1 cytokines IFNγ and TNFαα, ii) decreased expression of the Th1 genes T-box protein expressed in T cells (T-bet), Stat-1 and Stat4, and iii) decreased STAT1α/β phosphorylation. Importantly, we observed that LCA impairs Th1 activation at physiological relevant concentrations. Profiling of MAPK signaling pathways in Jurkat T cells uncovered an inhibition of ERK-1/2 phosphorylation upon LCA exposure, which could provide an explanation for the impaired Th1 activation. LCA induces these effects via Vitamin D receptor (VDR) signaling since VDR RNA silencing abrogated these effects. These data reveal for the first time that LCA controls adaptive immunity via inhibition of Th1 activation. Many factors influence LCA levels, including bile acid-based drugs and gut microbiota. Our data may suggest that these factors also impact on adaptive immunity via a yet unrecognized LCA-Th cell axis.

  3. Polymorphisms of genes coding for ghrelin and its receptor in relation to colorectal cancer risk: a two-step gene-wide case-control study.

    Science.gov (United States)

    Campa, Daniele; Pardini, Barbara; Naccarati, Alessio; Vodickova, Ludmila; Novotny, Jan; Steinke, Verena; Rahner, Nils; Holinski-Feder, Elke; Morak, Monika; Schackert, Hans K; Görgens, Heike; Kötting, Judith; Betz, Beate; Kloor, Matthias; Engel, Christoph; Büttner, Reinhard; Propping, Peter; Försti, Asta; Hemminki, Kari; Barale, Roberto; Vodicka, Pavel; Canzian, Federico

    2010-09-28

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (Ptrend = 0.004).

  4. mRNA expression of 5-hydroxytryptamine 1B, 1D, and 1F receptors and their role in controlling the release of calcitonin gene-related peptide in the rat trigeminovascular system

    DEFF Research Database (Denmark)

    Amrutkar, Dipak V; Ploug, Kenneth B; Hay-Schmidt, Anders

    2012-01-01

    Triptans, a family of 5-hydroxytryptamine (5-HT) 1B, 1D, and 1F receptor agonists, are used in the acute treatment of migraine attacks. The site of action and subtypes of the 5-HT(1) receptor that mediate the antimigraine effect have still to be identified. This study investigated the mRNA expres......Triptans, a family of 5-hydroxytryptamine (5-HT) 1B, 1D, and 1F receptor agonists, are used in the acute treatment of migraine attacks. The site of action and subtypes of the 5-HT(1) receptor that mediate the antimigraine effect have still to be identified. This study investigated the m......RNA expression of these receptors and the role of 5-HT(1) receptor subtypes in controlling the release of calcitonin gene-related peptide (CGRP) in rat dura mater, trigeminal ganglion (TG), and trigeminal nucleus caudalis (TNC). The mRNA for each receptor subtype was quantified by quantitative real...

  5. Excitatory amino acid receptor ligands: resolution, absolute stereochemistry, and enantiopharmacology of 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid

    DEFF Research Database (Denmark)

    Johansen, T N; Ebert, B; Bräuner-Osborne, Hans

    1998-01-01

    (RS)-2-Amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid (Bu-HIBO, 6) has previously been shown to be an agonist at (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors and an inhibitor of CaCl2-dependent [3H]-(S)-glutamic acid binding (J. Med. Chem. 1992, 35, 3512......-3519). To elucidate the pharmacological significance of this latter binding affinity, which is also shown by quisqualic acid (3) but not by AMPA, we have now resolved Bu-HIBO via diastereomeric salt formation using the diprotected Bu-HIBO derivative 11 and the enantiomers of 1-phenylethylamine (PEA). The absolute...... equipotent as inhibitors of CaCl2-dependent [3H]-(S)-glutamic acid binding, neither enantiomer showed significant affinity for the synaptosomal (S)-glutamic acid uptake system(s). AMPA receptor affinity (IC50 = 0.48 microM) and agonism (EC50 = 17 microM) were shown to reside exclusively in the S...

  6. Association of nicotinic acetylcholine receptors with central respiratory control in isolated brainstem-spinal cord preparation of neonatal rats

    Directory of Open Access Journals (Sweden)

    EIKI HATORI

    2006-01-01

    Full Text Available Nicotine exposure is a risk factor in several breathing disorders Nicotinic acetylcholine receptors (nAChRs exist in the ventrolateral medulla, an important site for respiratory control. We examined the effects of nicotinic acetylcholine neurotransmission on central respiratory control by addition of a nAChR agonist or one of various antagonists into superfusion medium in the isolated brainstem-spinal cord from neonatal rats. Ventral C4 neuronal activity was monitored as central respiratory output, and activities of respiratory neurons in the ventrolateral medulla were recorded in whole-cell configuration. RJR-2403 (0.1-10mM, alpha4beta2 nAChR agonist induced dose-dependent increases in respiratory frequency. Non-selective nAChR antagonist mecamylamine (0.1-100mM, alpha4beta2 antagonist dihydro-beta-erythroidine (0.1-100mM, alpha7 antagonist methyllycaconitine (0.1-100mM, and a-bungarotoxin (0.01-10mM all induced dose-dependent reductions in C4 respiratory rate. We next examined effects of 20mM dihydro-beta-erythroidine and 20mM methyllycaconitine on respiratory neurons. Dihydro-beta-erythroidine induces hyperpolarization and decreases intraburst firing frequency of inspiratory and preinspiratory neurons. In contrast, methyllycaconitine has no effect on the membrane potential of inspiratory neurons, but does decrease their intraburst firing frequency while inducing hyperpolarization and decreasing intraburst firing frequency in preinspiratory neurons. These findings indicate that alpha4beta2 nAChR is involved in both inspiratory and preinspiratory neurons, whereas alpha7 nAChR functions only in preinspiratory neurons to modulate C4 respiratory rate

  7. Lateral hypothalamic GLP-1 receptors are critical for the control of food reinforcement, ingestive behavior and body weight.

    Science.gov (United States)

    López-Ferreras, L; Richard, J E; Noble, E E; Eerola, K; Anderberg, R H; Olandersson, K; Taing, L; Kanoski, S E; Hayes, M R; Skibicka, K P

    2017-09-12

    Increased motivation for highly rewarding food is a major contributing factor to obesity. Most of the literature focuses on the mesolimbic nuclei as the core of reward behavior regulation. However, the lateral hypothalamus (LH) is also a key reward-control locus in the brain. Here we hypothesize that manipulating glucagon-like peptide-1 receptor (GLP-1R) activity selectively in the LH can profoundly affect food reward behavior, ultimately leading to obesity. Progressive ratio operant responding for sucrose was examined in male and female rats, following GLP-1R activation and pharmacological or genetic GLP-1R blockade in the LH. Ingestive behavior and metabolic parameters, as well as molecular and efferent targets, of the LH GLP-1R activation were also evaluated. Food motivation was reduced by activation of LH GLP-1R. Conversely, acute pharmacological blockade of LH GLP-1R increased food motivation but only in male rats. GLP-1R activation also induced a robust reduction in food intake and body weight. Chronic knockdown of LH GLP-1R induced by intraparenchymal delivery of an adeno-associated virus-short hairpin RNA construct was sufficient to markedly and persistently elevate ingestive behavior and body weight and ultimately resulted in a doubling of fat mass in males and females. Interestingly, increased food reinforcement was again found only in males. Our data identify the LH GLP-1R as an indispensable element of normal food reinforcement, food intake and body weight regulation. These findings also show, for we believe the first time, that brain GLP-1R manipulation can result in a robust and chronic body weight gain. The broader implications of these findings are that the LH differs between females and males in its ability to control motivated and ingestive behaviors.Molecular Psychiatry advance online publication, 12 September 2017; doi:10.1038/mp.2017.187.

  8. Role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation

    International Nuclear Information System (INIS)

    Waldmann, T.A.

    1987-01-01

    Antigen-induced activation of resting T-cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. The authors have identified two IL-2 binding peptides, a 55-kd peptide reactive with the anti-Tac monoclonal antibody, and a novel 75-kd non-Tac IL-2 binding peptide. Cell lines bearing either the p55, Tac, or the p75 peptide along manifested low-affinity IL-2 binding, whereas cell lines bearing both peptides manifested both high- and low-affinity receptors. Fusion of cell membranes from low-affinity IL-2 binding cells bearing the Tac peptide alone with membranes from a cell line bearing the p75 peptide alone generates hybrid membranes bearing high-affinity receptors. They propose a multichain model for the high-affinity IL-2 receptor in which both the Tac and the p75 IL-2 binding peptides are associated in a receptor complex. In contrast to resting T-cells, human T-cell lymphotropic virus I-associated adult T-cell leukemia cells constitutively express large numbers of IL-2 receptors. Because IL-2 receptors are present on the malignant T-cells but not on normal resting cells, clinical trials have been initiated in which patients with adult T-cell leukemia are being treated with either unmodified or toxin-conjugated forms of anti-Tac monoclonal antibody directed toward this growth factor receptor. Cross-linking studies were done using [ 125 I] IL-2

  9. Role of glutamatergic receptors located in the nucleus raphe magnus on antinociceptive effect of morphine microinjected into the nucleus cuneiformis of rat.

    Science.gov (United States)

    Haghparast, Abbas; Soltani-Hekmat, Ava; Khani, Abbas; Komaki, Alireza

    2007-10-29

    Neurons in the nucleus cuneiformis (CnF), located just ventrolateral to the periaqueductal gray, project to medullary nucleus raphe magnus (NRM), which is a key medullary relay for descending pain modulation and is critically involved in opioid-induced analgesia. Previous studies have shown that antinociceptive response of CnF-microinjected morphine can be modulated by the specific subtypes of glutamatergic receptors within the CnF. In this study, we evaluated the role of NMDA and kainate/AMPA receptors that are widely distributed within the NRM on morphine-induced antinociception elicited from the CnF. Hundred and five male Wistar rats weighing 250-300 g were used. Morphine (10, 20 and 40 microg) and NMDA receptor antagonist, MK-801 (10 microg) or kainate/AMPA receptor antagonist, DNQX (0.5 microg) in 0.5 microl saline were stereotaxically microinjected into the CnF and NRM, respectively. The latency of tail-flick response was measured at set intervals (2, 7, 12, 17, 22, 27 min after microinjection) by using an automated tail-flick analgesiometer. The results showed that morphine microinjection into the CnF dose-dependently causes increase in tail-flick latency (TFL). MK-801 microinjected into the NRM, just 1 min before morphine injection into the CnF, significantly attenuated antinociceptive effects of morphine. On the other hand, DNQX microinjected into the NRM, significantly increased TFL after local application of morphine into the CnF. We suggest that morphine related antinociceptive effect elicited from the CnF is mediated, in part, by NMDA receptor at the level of the NRM whereas kainite/AMPA receptor has a net inhibitory influence at the same pathway.

  10. Anandamide Revisited: How Cholesterol and Ceramides Control Receptor-Dependent and Receptor-Independent Signal Transmission Pathways of a Lipid Neurotransmitter.

    Science.gov (United States)

    Di Scala, Coralie; Fantini, Jacques; Yahi, Nouara; Barrantes, Francisco J; Chahinian, Henri

    2018-05-22

    Anandamide is a lipid neurotransmitter derived from arachidonic acid, a polyunsaturated fatty acid. The chemical differences between anandamide and arachidonic acid result in a slightly enhanced solubility in water and absence of an ionisable group for the neurotransmitter compared with the fatty acid. In this review, we first analyze the conformational flexibility of anandamide in aqueous and membrane phases. We next study the interaction of the neurotransmitter with membrane lipids and discuss the molecular basis of the unexpected selectivity of anandamide for cholesterol and ceramide from among other membrane lipids. We show that cholesterol behaves as a binding partner for anandamide, and that following an initial interaction mediated by the establishment of a hydrogen bond, anandamide is attracted towards the membrane interior, where it forms a molecular complex with cholesterol after a functional conformation adaptation to the apolar membrane milieu. The complex is then directed to the anandamide cannabinoid receptor (CB1) which displays a high affinity binding pocket for anandamide. We propose that cholesterol may regulate the entry and exit of anandamide in and out of CB1 by interacting with low affinity cholesterol recognition sites (CARC and CRAC) located in transmembrane helices. The mirror topology of cholesterol binding sites in the seventh transmembrane domain is consistent with the delivery, extraction and flip-flop of anandamide through a coordinated cholesterol-dependent mechanism. The binding of anandamide to ceramide illustrates another key function of membrane lipids which may occur independently of protein receptors. Interestingly, ceramide forms a tight complex with anandamide which blocks the degradation pathway of both lipids and could be exploited for anti-cancer therapies.

  11. Differences between seizure-prone and non-seizure-prone mice with regard to glutamate and GABA receptor binding in the hippocampus and other regions of the brain

    DEFF Research Database (Denmark)

    Frandsen, A; Belhage, B; Schousboe, A

    1987-01-01

    Quisqualate-preferring glutamate receptors were determined in membranes from frontal cortex, occipital cortex, hippocampus and cerebellum, from seizure-prone DBA/2J BOM and seizure-resistant C57/BL mice. The animals were studied 21, 27 and 40 days postnatally, i.e., before, during and after the age...... at which DBA mice are most susceptible to seizures. Radio-binding assays were performed using [3H]AMPA in the presence of 100 nM glutamate. Except for the occipital cortex, where no significant differences between the two strains were observed, all areas of the brain of DBA mice exhibited significantly (P...... less than 0.001, t test) higher AMPA binding than the corresponding areas of C57/BL mice at 27 days of age. At pre- and post-susceptible ages, the two strains showed no significant differences in the hippocampus and occipital cortex. A significant difference was observed, however, in the frontal cortex...

  12. Testosterone treatment increases androgen receptor and aromatase gene expression in myotubes from patients with PCOS and controls, but does not induce insulin resistance.

    Science.gov (United States)

    Eriksen, Mette Brandt; Glintborg, Dorte; Nielsen, Michael Friberg Bruun; Jakobsen, Marianne Antonius; Brusgaard, Klaus; Tan, Qihua; Gaster, Michael

    2014-09-05

    Polycystic ovary syndrome (PCOS) is associated with insulin resistance and increased risk of type 2 diabetes. Skeletal muscle is the major site of insulin mediated glucose disposal and the skeletal muscle tissue is capable to synthesize, convert and degrade androgens. Insulin sensitivity is conserved in cultured myotubes (in vitro) from patients with PCOS, but the effect of testosterone on this insulin sensitivity is unknown. We investigated the effect of 7days testosterone treatment (100nmol/l) on glucose transport and gene expression levels of hormone receptors and enzymes involved in the synthesis and conversion of testosterone (HSD17B1, HSD17B2, CYP19A1, SRD5A1-2, AR, ER-α, HSD17B6 and AKR1-3) in myotubes from ten patients with PCOS and ten matched controls. Testosterone treatment significantly increased aromatase and androgen receptor gene expression levels in patients and controls. Glucose transport in myotubes was comparable in patients with PCOS vs. controls and was unchanged by testosterone treatment (p=0.21 PCOS vs. controls). These results suggest that testosterone treatment of myotubes increases the aromatase and androgen receptor gene expression without affecting insulin sensitivity and if testosterone is implicated in muscular insulin resistance in PCOS, this is by and indirect mechanism. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Cannabinoid transmission in the prelimbic cortex bidirectionally controls opiate reward and aversion signaling through dissociable kappa versus μ-opiate receptor dependent mechanisms.

    Science.gov (United States)

    Ahmad, Tasha; Lauzon, Nicole M; de Jaeger, Xavier; Laviolette, Steven R

    2013-09-25

    Cannabinoid, dopamine (DA), and opiate receptor pathways play integrative roles in emotional learning, associative memory, and sensory perception. Modulation of cannabinoid CB1 receptor transmission within the medial prefrontal cortex (mPFC) regulates the emotional valence of both rewarding and aversive experiences. Furthermore, CB1 receptor substrates functionally interact with opiate-related motivational processing circuits, particularly in the context of reward-related learning and memory. Considerable evidence demonstrates functional interactions between CB1 and DA signaling pathways during the processing of motivationally salient information. However, the role of mPFC CB1 receptor transmission in the modulation of behavioral opiate-reward processing is not currently known. Using an unbiased conditioned place preference paradigm with rats, we examined the role of intra-mPFC CB1 transmission during opiate reward learning. We report that activation or inhibition of CB1 transmission within the prelimbic cortical (PLC) division of the mPFC bidirectionally regulates the motivational valence of opiates; whereas CB1 activation switched morphine reward signaling into an aversive stimulus, blockade of CB1 transmission potentiated the rewarding properties of normally sub-reward threshold conditioning doses of morphine. Both of these effects were dependent upon DA transmission as systemic blockade of DAergic transmission prevented CB1-dependent modulation of morphine reward and aversion behaviors. We further report that CB1-mediated intra-PLC opiate motivational signaling is mediated through a μ-opiate receptor-dependent reward pathway, or a κ-opiate receptor-dependent aversion pathway, directly within the ventral tegmental area. Our results provide evidence for a novel CB1-mediated motivational valence switching mechanism within the PLC, controlling dissociable subcortical reward and aversion pathways.

  14. Enhanced Androgen Signaling With Androgen Receptor Overexpression in the Osteoblast Lineage Controls Skeletal Turnover, Matrix Quality and Bone Architecture

    National Research Council Canada - National Science Library

    Wiren, Kristine M; Jepsen, Karl

    2006-01-01

    .... We genetically engineered transgenic mice in which androgen receptor (AR) overexpression is skeletally targeted in two separate models to better understand the role of androgen signaling directly in bone...

  15. Pengaruh Panjang Serat Terhadap Nilai Koefisien Absorpsi Suara dan Sifat Mekanik Komposit Serat Ampas Tebu dengan Matriks Gipsum

    Directory of Open Access Journals (Sweden)

    Stefanus Laga Suban

    2015-03-01

    Full Text Available Penelitian ini dilakukan untuk membuat material komposit gipsum berpenguat serat alam untuk bahan penyerap suara. Permasalahan yang dikaji adalah untuk mengetahui hubungan panjang serat pada komposit ampas tebu bermatrik  gipsum terhadap nilai koefisien absorpsi suara (α, kekuatan tekan, dan kekuatan lenturnya. Panjang serat yang digunakan adalah 10mm, 30mm, dan 50mm  dengan fraksi volum 30% serat : 70% gipsum. Tujuannya untuk mendapatkan hubungan nilai koefisien absorpsi suara, kuat lentur, dan kuat tekan dengan panjang serat yang diberikan serta aplikasinya dalam material bahan penyerap suara yang memenuhi standar ISO 11654. Metode pembuatan spesimen komposit yang digunakan adalah hand lay up. Metode pengujian berdasarkan standart ASTM E1050 untuk pengujian koefisien absorpsi suara, ASTM D790 untuk pengujian kuat lentur, dan ASTM D695 untuk pengujian kuat tekan. Dari hasil pengujian didapatkan nilai koefisien absorpsi suara memenuhi standar ISO 11654 dengan nilai koefisien α lebih besar dari 0,15. Nilai kuat lentur terbaik ialah pada panjang serat 30mm sebesar 1,952 MPa. Nilai kuat tekan terbaik ialah pada panjang serat 50mm sebesar 2,005 MPa

  16. ERK controls epithelial cell death receptor signalling and cellular FLICE-like inhibitory protein (c-FLIP) in ulcerative colitis

    DEFF Research Database (Denmark)

    Seidelin, Jakob Benedict; Coskun, Mehmet; Vainer, Ben

    2013-01-01

    Intestinal epithelial cell (IEC) death signalling through the Fas receptor is impaired in active ulcerative colitis (UC). This is possibly due to the activation of cytoprotective pathways resulting in limitation of the tissue injury secondary to inflammation. We hypothesized that inflammatory...... the resistance to receptor mediated epithelial apoptosis in active UC. Oncogenic c-FLIP could promote propagation of DNA-damaged IECs and contribute to cancer development in UC....

  17. Effects of the antitumor drug OSI-906, a dual inhibitor of IGF-1 receptor and insulin receptor, on the glycemic control, β-cell functions, and β-cell proliferation in male mice.

    Science.gov (United States)

    Shirakawa, Jun; Okuyama, Tomoko; Yoshida, Eiko; Shimizu, Mari; Horigome, Yuka; Tuno, Takayuki; Hayasaka, Moe; Abe, Shiori; Fuse, Masahiro; Togashi, Yu; Terauchi, Yasuo

    2014-06-01

    The IGF-1 receptor has become a therapeutic target for the treatment of cancer. The efficacy of OSI-906 (linstinib), a dual inhibitor of IGF-1 receptor and insulin receptor, for solid cancers has been examined in clinical trials. The effects of OSI-906, however, on the blood glucose levels and pancreatic β-cell functions have not yet been reported. We investigated the impact of OSI-906 on glycemic control, insulin secretion, β-cell mass, and β-cell proliferation in male mice. Oral administration of OSI-906 worsened glucose tolerance in a dose-dependent manner in the wild-type mice. OSI-906 at a dose equivalent to the clinical daily dose (7.5 mg/kg) transiently evoked glucose intolerance and hyperinsulinemia. Insulin receptor substrate (IRS)-2-deficient mice and mice with diet-induced obesity, both models of peripheral insulin resistance, exhibited more severe glucose intolerance after OSI-906 administration than glucokinase-haploinsufficient mice, a model of impaired insulin secretion. Phloridzin improved the hyperglycemia induced by OSI-906 in mice. In vitro, OSI-906 showed no effect on insulin secretion from isolated islets. After daily administration of OSI-906 for a week to mice, the β-cell mass and β-cell proliferation rate were significantly increased. The insulin signals in the β-cells were apparently unaffected in those mice. Taken together, the results suggest that OSI-906 could exacerbate diabetes, especially in patients with insulin resistance. On the other hand, the results suggest that the β-cell mass may expand in response to chemotherapy with this drug.

  18. Association of Estrogen Receptor Gene Polymorphisms and Primary Biliary Cirrhosis in a Chinese Population: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-01-01

    Full Text Available Background: Primary biliary cirrhosis (PBC is a chronic and slowly progressive cholestatic liver disease characterized by destruction of the interlobular bile ducts and a striking female predominance. The aim of this study was to identify associations between estrogen receptor (ESR gene polymorphisms with the risk of developing PBC and abnormal serum liver tests in a Chinese population. Methods: Thirty-six patients with PBC (case group and 35 healthy individuals (control group from the First Hospital of Jilin University were studied. Whole genomic DNA was extracted from all the participants. Three single-nucleotide polymorphisms (rs2234693, rs2228480, and rs3798577 from ESR1 and two (rs1256030 and rs1048315 from ESR2 were analyzed by a pyrosequencing method. Demographic data and liver biochemical data were collected. Results: Subjects with the T allele at ESR2 rs1256030 had 1.5 times higher risk of developing PBC than those with the C allele (odds ratio [OR] = 2.1277, 95% confidence interval [CI] = 1.1872-4.5517. Haplotypes TGC of ESR1 rs2234693, rs2228480, and rs3798577 were risk factors for having PBC. The C allele at ESR1 rs2234693 was associated with abnormal alkaline phosphatase (OR = 5.2469, 95% CI = 1.3704-20.0895 and gamma-glutamyl transferase (OR = 3.4286, 95% CI = 1.0083-13.6578 levels in PBC patients. Conclusions: ESR2 rs1256030 T allele may be a significant risk factor for the development of PBC. Screening for patients with gene polymorphisms may help to make early diagnoses in patients with PBC.

  19. Olfactory bulb glomerular NMDA receptors mediate olfactory nerve potentiation and odor preference learning in the neonate rat.

    Directory of Open Access Journals (Sweden)

    Rebecca Lethbridge

    Full Text Available Rat pup odor preference learning follows pairing of bulbar beta-adrenoceptor activation with olfactory input. We hypothesize that NMDA receptor (NMDAR-mediated olfactory input to mitral cells is enhanced during training, such that increased calcium facilitates and shapes the critical cAMP pattern. Here, we demonstrate, in vitro, that olfactory nerve stimulation, at sniffing frequencies, paired with beta-adrenoceptor activation, potentiates olfactory nerve-evoked mitral cell firing. This potentiation is blocked by a NMDAR antagonist and by increased inhibition. Glomerular disinhibition also induces NMDAR-sensitive potentiation. In vivo, in parallel, behavioral learning is prevented by glomerular infusion of an NMDAR antagonist or a GABA(A receptor agonist. A glomerular GABA(A receptor antagonist paired with odor can induce NMDAR-dependent learning. The NMDA GluN1 subunit is phosphorylated in odor-specific glomeruli within 5 min of training suggesting early activation, and enhanced calcium entry, during acquisition. The GluN1 subunit is down-regulated 3 h after learning; and at 24 h post-training the GluN2B subunit is down-regulated. These events may assist memory stability. Ex vivo experiments using bulbs from trained rat pups reveal an increase in the AMPA/NMDA EPSC ratio post-training, consistent with an increase in AMPA receptor insertion and/or the decrease in NMDAR subunits. These results support a model of a cAMP/NMDA interaction in generating rat pup odor preference learning.

  20. Biochemical characterization of an autoradiographic method for studying excitatory amino acid receptors using L-[3H]glutamate

    International Nuclear Information System (INIS)

    Cincotta, M.; Summers, R.J.; Beart, P.M.

    1989-01-01

    A method was developed for radiolabeling excitatory amino acid receptors of rat brain with L-[ 3 H]glutamate. Effective labeling of glutamate receptors in slide-mounted 10-microns sections was obtained using a low incubation volume (0.15 ml) and rapid washing: a procedure where high ligand concentrations were achieved with minimal waste. Saturation experiments using [ 3 H]glutamate revealed a single binding site of micromolar affinity. The Bmax was trebled in the presence of Ca2+ (2.5 mM) and Cl- (20 mM) with no change in the Kd. Binding was rapid, saturable, stereospecific, and sensitive to glutamate receptor agonists. The proportions of [ 3 H]glutamate binding sensitive to N-methyl-D-aspartate (NMDA), kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) were 34, 54, and 51%, respectively. NMDA inhibited binding at a distinct subset of L-[ 3 H]glutamate sites, whereas AMPA and kainate competed for some common sites. Labeling of sections with L-[ 3 H]glutamate in the presence of the selective agonists allowed autoradiographic visualization of glutamate receptor subtypes in brain tissue

  1. Receptor for advanced glycation end products involved in lung ischemia reperfusion injury in cardiopulmonary bypass attenuated by controlled oxygen reperfusion in a canine model.

    Science.gov (United States)

    Rong, Jian; Ye, Sheng; Liang, Meng-ya; Chen, Guang-xian; Liu, Hai; Zhang, Jin-Xin; Wu, Zhong-kai

    2013-01-01

    Controlled oxygen reperfusion could protect the lung against ischemia-reperfusion injury in cardiopulmonary bypass (CPB) by downregulating high mobility group box 1 (HMGB1), a high affinity receptor of HMGB1. This study investigated the effect of controlled oxygen reperfusion on receptor for advanced glycation end products (RAGE) expression and its downstream effects on lung ischemia-reperfusion injury. Fourteen canines received CPB with 60 minutes of aortic clamping and cardioplegic arrest followed by 90 minutes of reperfusion. Animals were randomized to receive 80% FiO2 during the entire procedure (control group) or to a test group receiving a controlled oxygen reperfusion protocol. Pathologic changes in lung tissues, RAGE expression, serum interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were evaluated. The lung pathologic scores after 25 and 90 minutes of reperfusion were significantly lower in the test group compared with the control group (p RAGE expression, TNF-α, and IL-6 were downregulated by controlled oxygen treatment (p RAGE might be involved in the lung ischemia-reperfusion injury in canine model of CPB, which was downregulated by controlled oxygen reperfusion.

  2. Antagonism of ionotropic glutamate receptors attenuates chemical ischemia-induced injury in rat primary cultured myenteric ganglia.

    Directory of Open Access Journals (Sweden)

    Elisa Carpanese

    Full Text Available Alterations of the enteric glutamatergic transmission may underlay changes in the function of myenteric neurons following intestinal ischemia and reperfusion (I/R contributing to impairment of gastrointestinal motility occurring in these pathological conditions. The aim of the present study was to evaluate whether glutamate receptors of the NMDA and AMPA/kainate type are involved in myenteric neuron cell damage induced by I/R. Primary cultured rat myenteric ganglia were exposed to sodium azide and glucose deprivation (in vitro chemical ischemia. After 6 days of culture, immunoreactivity for NMDA, AMPA and kainate receptors subunits, GluN(1 and GluA(1-3, GluK(1-3 respectively, was found in myenteric neurons. In myenteric cultured ganglia, in normal metabolic conditions, -AP5, an NMDA antagonist, decreased myenteric neuron number and viability, determined by calcein AM/ethidium homodimer-1 assay, and increased reactive oxygen species (ROS levels, measured with hydroxyphenyl fluorescein. CNQX, an AMPA/kainate antagonist exerted an opposite action on the same parameters. The total number and viability of myenteric neurons significantly decreased after I/R. In these conditions, the number of neurons staining for GluN1 and GluA(1-3 subunits remained unchanged, while, the number of GluK(1-3-immunopositive neurons increased. After I/R, -AP5 and CNQX, concentration-dependently increased myenteric neuron number and significantly increased the number of living neurons. Both -AP5 and CNQX (100-500 µM decreased I/R-induced increase of ROS levels in myenteric ganglia. On the whole, the present data provide evidence that, under normal metabolic conditions, the enteric glutamatergic system exerts a dualistic effect on cultured myenteric ganglia, either by improving or reducing neuron survival via NMDA or AMPA/kainate receptor activation, respectively. However, blockade of both receptor pathways may exert a protective role on myenteric neurons following and I

  3. Intrathecal infusion of a Ca(2+)-permeable AMPA channel blocker slows loss of both motor neurons and of the astrocyte glutamate transporter, GLT-1 in a mutant SOD1 rat model of ALS.

    Science.gov (United States)

    Yin, Hong Z; Tang, Darryl T; Weiss, John H

    2007-10-01

    Elevated extracellular glutamate, resulting from a loss of astrocytic glutamate transport capacity, may contribute to excitotoxic motor neuron (MN) damage in ALS. Accounting for their high excitotoxic vulnerability, MNs possess large numbers of unusual Ca(2+)-permeable AMPA channels (Ca-AMPA channels), the activation of which triggers mitochondrial Ca(2+) overload and strong reactive oxygen species (ROS) generation. However, the causes of the astrocytic glutamate transport loss remain unexplained. To assess the role of Ca-AMPA channels on the evolution of pathology in vivo, we have examined effects of prolonged intrathecal infusion of the Ca-AMPA channel blocker, 1-naphthyl acetylspermine (NAS), in G93A transgenic rat models of ALS. In wild-type animals, immunoreactivity for the astrocytic glutamate transporter, GLT-1, was particularly strong around ventral horn MNs. However, a marked loss of ventral horn GLT-1 was observed, along with substantial MN damage, prior to onset of symptoms (90-100 days) in the G93A rats. Conversely, labeling with the oxidative marker, nitrotyrosine, was increased in the neuropil surrounding MNs in the transgenic animals. Compared to sham-treated G93A animals, 30-day NAS infusions (starting at 67+/-2 days of age) markedly diminished the loss of both MNs and of astrocytic GLT-1 labeling. These observations are compatible with the hypothesis that activation of Ca-AMPA channels on MNs contributes, likely in part through oxidative mechanisms, to loss of glutamate transporter in surrounding astrocytes.

  4. Somatostatin receptors

    DEFF Research Database (Denmark)

    Møller, Lars Neisig; Stidsen, Carsten Enggaard; Hartmann, Bolette

    2003-01-01

    functional units, receptors co-operate. The total receptor apparatus of individual cell types is composed of different-ligand receptors (e.g. SRIF and non-SRIF receptors) and co-expressed receptor subtypes (e.g. sst(2) and sst(5) receptors) in characteristic proportions. In other words, levels of individual......-peptides, receptor agonists and antagonists. Relatively long half lives, as compared to those of the endogenous ligands, have been paramount from the outset. Motivated by theoretical puzzles or the shortcomings of present-day diagnostics and therapy, investigators have also aimed to produce subtype...

  5. Phytoestrogens/insoluble fibers and colonic estrogen receptor β: Randomized, double-blind, placebo-controlled study

    Science.gov (United States)

    Principi, Mariabeatrice; Di Leo, Alfredo; Pricci, Maria; Scavo, Maria Principia; Guido, Raffaella; Tanzi, Sabina; Piscitelli, Domenico; Pisani, Antonio; Ierardi, Enzo; Comelli, Maria Cristina; Barone, Michele

    2013-01-01

    AIM: To assess the safety and effect of the supplementation of a patented blend of dietary phytoestrogens and insoluble fibers on estrogen receptor (ER)-β and biological parameters in sporadic colonic adenomas. METHODS: A randomized, double-blind placebo-controlled trial was performed. Patients scheduled to undergo surveillance colonoscopy for previous sporadic colonic adenomas were identified, and 60 eligible patients were randomized to placebo or active dietary intervention (ADI) twice a day, for 60 d before surveillance colonoscopy. ADI was a mixture of 175 mg milk thistle extract, 20 mg secoisolariciresinol and 750 mg oat fiber extract. ER-β and ER-α expression, apoptosis and proliferation (Ki-67 LI) were assessed in colon samples. RESULTS: No adverse event related to ADI was recorded. ADI administration showed a significant increases in ER-β protein (0.822 ± 0.08 vs 0.768 ± 0.10, P = 0.04) and a general trend to an increase in ER-β LI (39.222 ± 2.69 vs 37.708 ± 5.31, P = 0.06), ER-β/ER-α LI ratio (6.564 ± 10.04 vs 2.437 ± 1.53, P = 0.06), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (35.592 ± 14.97 vs 31.541 ± 11.54, P = 0.07) and Ki-67 (53.923 ± 20.91 vs 44.833 ± 10.38, P = 0.07) approximating statistical significance. A significant increase of ER-β protein (0.805 ± 0.13 vs 0.773 ± 0.13, P = 0.04), mRNA (2.278 ± 1.19 vs 1.105 ± 1.07, P < 0.02) and LI (47.533 ± 15.47 vs 34.875 ± 16.67, P < 0.05) and a decrease of ER-α protein (0.423 ± 0.06 vs 0.532 ± 0.11, P < 0.02) as well as a trend to increase of ER-β/ER-α protein in ADI vs placebo group were observed in patients without polyps (1.734 ± 0.20 vs 1.571 ± 0.42, P = 0.07). CONCLUSION: The role of ER-β on the control of apoptosis, and its amenability to dietary intervention, are supported in our study. PMID:23885143

  6. The synthetic inhibitor of Fibroblast Growth Factor Receptor PD166866 controls negatively the growth of tumor cells in culture

    Directory of Open Access Journals (Sweden)

    Castelli Mauro

    2009-12-01

    Full Text Available Abstract Background Many experimental data evidence that over-expression of various growth factors cause disorders in cell proliferation. The role of the Fibroblast Growth Factors (FGF in growth control is indisputable: in particular, FGF1 and its tyrosine kinase receptor (FGFR1 act through a very complex network of mechanisms and pathways. In this work we have evaluated the antiproliferative activity effect of PD166866, a synthetic molecule inhibiting the tyrosin kinase action of FGFR1. Methods Cells were routinely grown in Dulbecco Modified Eagle's medium supplemented with newborn serum and a penicillin-streptomycin mixture. Cell viability was evaluated by Mosmann assay and by trypan blue staining. DNA damage was assessed by in situ fluorescent staining with Terminal Deoxynucleotidyl Transferase dUTP nick end labeling (TUNEL assay. Assessment of oxidative stress at membrane level was measured by quantitative analysis of the intra-cellular formation of malonyl-dialdheyde (MDA deriving from the decomposition of poly-unsaturated fatty acids. The expression of Poly-ADP-Ribose-Polymerase (PARP, consequent to DNA fragmentation, was evidenced by immuno-histochemistry utilizing an antibody directed against an N-terminal fragment of the enzyme. Results The bioactivity of the drug was investigated on Hela cells. Cytoxicity was assessed by the Mosmann assay and by vital staining with trypan blue. The target of the molecule is most likely the cell membrane as shown by the significant increase of the intracellular concentration of malonyl-dihaldheyde. The increase of this compound, as a consequence of the treatment with PD166866, is suggestive of membrane lipoperoxidation. The TUNEL assay gave a qualitative, though clear, indication of DNA damage. Furthermore we demonstrate intracellular accumulation of poly-ADP-ribose polymerase I. This enzyme is a sensor of nicks on the DNA strands and this supports the idea that treatment with the drug induces cell

  7. A Transcriptional Regulatory Network Containing Nuclear Receptors and Long Noncoding RNAs Controls Basal and Drug-Induced Expression of Cytochrome P450s in HepaRG Cells.

    Science.gov (United States)

    Chen, Liming; Bao, Yifan; Piekos, Stephanie C; Zhu, Kexin; Zhang, Lirong; Zhong, Xiao-Bo

    2018-07-01

    Cytochrome P450 (P450) enzymes are responsible for metabolizing drugs. Expression of P450s can directly affect drug metabolism, resulting in various outcomes in therapeutic efficacy and adverse effects. Several nuclear receptors are transcription factors that can regulate expression of P450s at both basal and drug-induced levels. Some long noncoding RNAs (lncRNAs) near a transcription factor are found to participate in the regulatory functions of the transcription factors. The aim of this study is to determine whether there is a transcriptional regulatory network containing nuclear receptors and lncRNAs controlling both basal and drug-induced expression of P450s in HepaRG cells. Small interfering RNAs or small hairpin RNAs were applied to knock down four nuclear receptors [hepatocyte nuclear factor 1 α (HNF1 α ), hepatocyte nuclear factor 4 α (HNF4 α ), pregnane X receptor (PXR), and constitutive androstane receptor (CAR)] as well as two lncRNAs [HNF1 α antisense RNA 1 (HNF1 α -AS1) and HNF4 α antisense RNA 1 (HNF4 α -AS1)] in HepaRG cells with or without treatment of phenobarbital or rifampicin. Expression of eight P450 enzymes was examined in both basal and drug-induced levels. CAR and PXR mainly regulated expression of specific P450s. HNF1 α and HNF4 α affected expression of a wide range of P450s as well as other transcription factors. HNF1 α and HNF4 α controlled the expression of their neighborhood lncRNAs, HNF1 α -AS1 and HNF4 α -AS1, respectively. HNF1 α -AS1 and HNF4 α -AS1 was also involved in the regulation of P450s and transcription factors in diverse manners. Altogether, our study concludes that a transcription regulatory network containing the nuclear receptors and lncRNAs controls both basal and drug-induced expression of P450s in HepaRG cells. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

  8. Reduced type II interleukin-4 receptor signalling drives initiation, but not progression, of colorectal carcinogenesis: evidence from transgenic mouse models and human case?control epidemiological observations

    OpenAIRE

    Ingram, Nicola; Northwood, Emma L.; Perry, Sarah L.; Marston, Gemma; Snowden, Helen; Taylor, John C.; Scott, Nigel; Bishop, D. Timothy; Coletta, P. Louise; Hull, Mark A.

    2013-01-01

    We investigated the role of interleukin (IL)-4 receptor (IL-4R) signalling during mouse carcinogen-induced colorectal carcinogenesis and in a case-control genetic epidemiological study of IL-4Rα single nucleotide polymorphisms (SNPs). Azoxymethane-induced aberrant crypt focus (ACF; 6 weeks) and tumours (32 weeks) were analysed in wild-type (WT) BALB/c mice, as well as in IL-4Rα (-) (/-) , IL-13 (-/-) and 'double-knockout' (DKO) animals. Colorectal cancer (CRC) cases (1502) and controls (584) ...

  9. Control of the subthalamic innervation of substantia nigra pars reticulata by D1 and D2 dopamine receptors.

    Science.gov (United States)

    Ibañez-Sandoval, Osvaldo; Hernández, Adán; Florán, Benjamin; Galarraga, Elvira; Tapia, Dagoberto; Valdiosera, Rene; Erlij, David; Aceves, Jorge; Bargas, José

    2006-03-01

    The effects of activating dopaminergic D1 and D2 class receptors of the subthalamic projections that innervate the pars reticulata of the subtantia nigra (SNr) were explored in slices of the rat brain using the whole cell patch-clamp technique. Excitatory postsynaptic currents (EPSCs) that could be blocked by 6-cyano-7-nitroquinoxalene-2,3-dione and D-(-)-2-amino-5-phosphonopentanoic acid were evoked onto reticulata GABAergic projection neurons by local field stimulation inside the subthalamic nucleus in the presence of bicuculline. Bath application of (RS)-2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine hydrochloride (SKF-38393), a dopaminergic D1-class receptor agonist, increased evoked EPSCs by approximately 30% whereas the D2-class receptor agonist, trans-(-)-4aR-4,4a,5,6,7,8,8a,9-octahydro-5-propyl-1H-pyrazolo(3,4-g)quinoline (quinpirole), reduced EPSCs by approximately 25%. These apparently opposing actions were blocked by the specific D1- and D2-class receptor antagonists: R-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetra-hydro-1H-3-benzazepinehydrochloride (SCH 23390) and S-(-)-5-amino-sulfonyl-N-[(1-ethyl-2-pyrrolidinyl)-methyl]-2-methoxybenzamide (sulpiride), respectively. Both effects were accompanied by changes in the paired-pulse ratio, indicative of a presynaptic site of action. The presynaptic location of dopamine receptors at the subthalamonigral projections was confirmed by mean-variance analysis. The effects of both SKF-38393 and quinpirole could be observed on terminals contacting the same postsynaptic neuron. Sulpiride and SCH 23390 enhanced and reduced the evoked EPSC, respectively, suggesting a constitutive receptor activation probably arising from endogenous dopamine. These data suggest that dopamine presynaptically modulates the subthalamic projection that targets GABAergic neurons of the SNr. Implications of this modulation for basal ganglia function are discussed.

  10. Properties of GluR3 receptors tagged with GFP at the amino or carboxyl terminus.

    Science.gov (United States)

    Limon, Agenor; Reyes-Ruiz, Jorge Mauricio; Eusebi, Fabrizio; Miledi, Ricardo

    2007-09-25

    Anatomical visualization of neurotransmitter receptor localization is facilitated by tagging receptors, but this process can alter their functional properties. We have evaluated the distribution and properties of WT glutamate receptor 3 (GluR3) alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (WT GluR3) and two receptors in which GFP was tagged to the amino terminus (GFP-GluR3) or to the carboxyl terminus (GluR3-GFP). Although the fluorescence in Xenopus oocytes was stronger in the vegetal hemisphere because of localization of internal structures (probable sites of production, storage or recycling of receptors), the insertion of receptors into the plasma membrane was polarized to the animal hemisphere. The fluorescence intensity of oocytes injected with GluR3-GFP RNA was approximately double that of oocytes injected with GFP-GluR3 RNA. Accordingly, GluR3-GFP oocytes generated larger kainate-induced currents than GFP-GluR3 oocytes, with similar EC(50) values. Currents elicited by glutamate, or AMPA coapplied with cyclothiazide, were also larger in GluR3-GFP oocytes. The glutamate- to kainate-current amplitude ratios differed, with GluR3-GFP being activated more efficiently by glutamate than the WT or GFP-GluR3 receptors. This pattern correlates with the slower decay of glutamate-induced currents generated by GluR3-GFP receptors. These changes were not observed when GFP was tagged to the amino terminus, and these receptors behaved like the WT. The antagonistic effects of 6-nitro-7-sulfamoylbenzo[f]quinoxaline-2,3-dione (NBQX) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) were not altered in any of the tagged receptors. We conclude that GFP is a useful and convenient tag for visualizing these proteins. However, the effects of different sites of tag insertion on receptor characteristics must be taken into account in assessing the roles played by these receptor proteins.

  11. Aryl hydrocarbon receptor-dependent regulation of miR-196a expression controls lung fibroblast apoptosis but not proliferation

    International Nuclear Information System (INIS)

    Hecht, Emelia; Zago, Michela; Sarill, Miles; Rico de Souza, Angela; Gomez, Alvin; Matthews, Jason; Hamid, Qutayba; Eidelman, David H.; Baglole, Carolyn J.

    2014-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor implicated in the regulation of apoptosis and proliferation. Although activation of the AhR by xenobiotics such as dioxin inhibits the cell cycle and control apoptosis, paradoxically, AhR expression also promotes cell proliferation and survival independent of exogenous ligands. The microRNA (miRNA) miR-196a has also emerged as a regulator of proliferation and apoptosis but a relationship between the AhR and miR-196a is not known. Therefore, we hypothesized that AhR-dependent regulation of endogenous miR-196a expression would promote cell survival and proliferation. Utilizing lung fibroblasts from AhR deficient (AhR −/− ) and wild-type (AhR +/+ ) mice, we show that there is ligand-independent regulation of miRNA, including low miR-196a in AhR −/− cells. Validation by qRT-PCR revealed a significant decrease in basal expression of miR-196a in AhR −/− compared to AhR +/+ cells. Exposure to AhR agonists benzo[a]pyrene (B[a]P) and FICZ as well as AhR antagonist CH-223191 decreased miR-196a expression in AhR +/+ fibroblasts concomitant with decreased AhR protein levels. There was increased proliferation only in AhR +/+ lung fibroblasts in response to serum, corresponding to a decrease in p27 KIP1 protein, a cyclin-dependent kinase inhibitor. Increasing the cellular levels of miR-196a had no effect on proliferation or expression of p27 KIP1 in AhR −/− fibroblasts but attenuated cigarette smoke-induced apoptosis. This study provides the first evidence that AhR expression is essential for the physiological regulation of cellular miRNA levels- including miR-196a. Future experiments designed to elucidate the functional relationship between the AhR and miR-196a may delineate additional novel ligand-independent roles for