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Sample records for ampa receptor trafficking

  1. PACSIN1 regulates the dynamics of AMPA receptor trafficking.

    Science.gov (United States)

    Widagdo, Jocelyn; Fang, Huaqiang; Jang, Se Eun; Anggono, Victor

    2016-01-01

    Dynamic trafficking of AMPA receptors (AMPARs) into and out of synapses plays an important role in synaptic plasticity. We previously reported that the protein kinase C and casein kinase II substrate in neurons (PACSIN) forms a complex with AMPARs through its interaction with the protein interacting with C-kinase 1 (PICK1) to regulate NMDA receptor (NMDAR)-induced AMPAR endocytosis and cerebellar long-term depression. However, the molecular mechanism by which PACSIN regulates the dynamics of AMPAR trafficking remains unclear. Using a pH-sensitive green fluorescent protein, pHluorin, tagged to the extracellular domain of the GluA2 subunit of AMPARs, we demonstrate dual roles for PACSIN1 in controlling the internalization and recycling of GluA2 after NMDAR activation. Structure and function analysis reveals a requirement for the PACSIN1 F-BAR and SH3 domains in controlling these NMDAR-dependent processes. Interestingly, the variable region, which binds to PICK1, is not essential for NMDAR-dependent GluA2 internalization and is required only for the correct recycling of AMPARs. These results indicate that PACSIN is a versatile membrane deformation protein that links the endocytic and recycling machineries essential for dynamic AMPAR trafficking in neurons. PMID:27488904

  2. PACSIN1 regulates the dynamics of AMPA receptor trafficking

    Science.gov (United States)

    Widagdo, Jocelyn; Fang, Huaqiang; Jang, Se Eun; Anggono, Victor

    2016-01-01

    Dynamic trafficking of AMPA receptors (AMPARs) into and out of synapses plays an important role in synaptic plasticity. We previously reported that the protein kinase C and casein kinase II substrate in neurons (PACSIN) forms a complex with AMPARs through its interaction with the protein interacting with C-kinase 1 (PICK1) to regulate NMDA receptor (NMDAR)-induced AMPAR endocytosis and cerebellar long-term depression. However, the molecular mechanism by which PACSIN regulates the dynamics of AMPAR trafficking remains unclear. Using a pH-sensitive green fluorescent protein, pHluorin, tagged to the extracellular domain of the GluA2 subunit of AMPARs, we demonstrate dual roles for PACSIN1 in controlling the internalization and recycling of GluA2 after NMDAR activation. Structure and function analysis reveals a requirement for the PACSIN1 F-BAR and SH3 domains in controlling these NMDAR-dependent processes. Interestingly, the variable region, which binds to PICK1, is not essential for NMDAR-dependent GluA2 internalization and is required only for the correct recycling of AMPARs. These results indicate that PACSIN is a versatile membrane deformation protein that links the endocytic and recycling machineries essential for dynamic AMPAR trafficking in neurons. PMID:27488904

  3. Actin-dependent mechanisms in AMPA receptor trafficking

    Directory of Open Access Journals (Sweden)

    Jonathan G Hanley

    2014-11-01

    Full Text Available The precise regulation of AMPA receptor (AMPAR number and subtype at the synapse is crucial for the regulation of excitatory neurotransmission, synaptic plasticity and the consequent formation of appropriate neural circuits during learning and memory. AMPAR trafficking involves the dynamic processes of exocytosis, endocytosis and endosomal recycling, all of which involve the actin cytoskeleton. The actin cytoskeleton is highly dynamic and highly regulated by an abundance of actin-binding proteins and upstream signalling pathways that modulate actin polymerization and depolymerisation. Actin dynamics generate forces that manipulate membranes in the process of vesicle biogenesis, and also for propelling vesicles through the cytoplasm to reach their destination. In addition, trafficking mechanisms exploit more stable aspects of the actin cytoskeleton by using actin-based motor proteins to traffic vesicular cargo along actin filaments. Numerous studies have shown that actin dynamics are critical for AMPAR localization and function. The identification of actin-binding proteins that physically interact with AMPAR subunits, and research into their mode of action is starting to shed light on the mechanisms involved. Such proteins either regulate actin dynamics to modulate mechanical forces exerted on AMPAR-containing membranes, or associate with actin filaments to target or transport AMPAR-containing vesicles to specific subcellular regions. In addition, actin-regulatory proteins that do not physically interact with AMPARs may influence AMPAR trafficking by regulating the local actin environment in the dendritic spine.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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.

  6. AMPA receptor trafficking and the mechanisms underlying synaptic plasticity and cognitive aging.

    Science.gov (United States)

    Henley, Jeremy M; Wilkinson, Kevin A

    2013-03-01

    Even in healthy individuals there is an inexorable agerelated decline in cognitive function. This is due, in large part, to reduced synaptic plasticity caused by changes in the molecular composition of the postsynaptic membrane. AMPA receptors (AMPARs) are glutamate-gated cation channels that mediate the overwhelming majority of fast excitatory transmission in the brain. Changes in AMPAR number and/or function are a core feature of synaptic plasticity and age-related cognitive decline, AMPARs are highly dynamic proteins that are subject to highly controlled trafficking, recycling, and/or degradation and replacement. This active regulation of AMPAR synthesis, targeting, synaptic dwell time, and degradation is fundamentally important for memory formation and storage. Further, aberrant AMPAR trafficking and consequent detrimental changes in synapses are strongly implicated in many brain diseases, which represent a vast social and economic burden. The purpose of this article is to provide an overview of the molecular and cellular AMPA receptor trafficking events that control synaptic responsiveness and plasticity, and highlight what is known currently known about how these processes change with age and disease. PMID:23576886

  7. 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…

  8. The ubiquitin ligase RPM-1 and the p38 MAPK PMK-3 regulate AMPA receptor trafficking.

    Directory of Open Access Journals (Sweden)

    Eun Chan Park

    Full Text Available Ubiquitination occurs at synapses, yet its role remains unclear. Previous studies demonstrated that the RPM-1 ubiquitin ligase organizes presynaptic boutons at neuromuscular junctions in C. elegans motorneurons. Here we find that RPM-1 has a novel postsynaptic role in interneurons, where it regulates the trafficking of the AMPA-type glutamate receptor GLR-1 from synapses into endosomes. Mutations in rpm-1 cause the aberrant accumulation of GLR-1 in neurites. Moreover, rpm-1 mutations enhance the endosomal accumulation of GLR-1 observed in mutants for lin-10, a Mint2 ortholog that promotes GLR-1 recycling from Syntaxin-13 containing endosomes. As in motorneurons, RPM-1 negatively regulates the pmk-3/p38 MAPK pathway in interneurons by repressing the protein levels of the MAPKKK DLK-1. This regulation of PMK-3 signaling is critical for RPM-1 function with respect to GLR-1 trafficking, as pmk-3 mutations suppress both lin-10 and rpm-1 mutations. Positive or negative changes in endocytosis mimic the effects of rpm-1 or pmk-3 mutations, respectively, on GLR-1 trafficking. Specifically, RAB-5(GDP, an inactive mutant of RAB-5 that reduces endocytosis, mimics the effect of pmk-3 mutations when introduced into wild-type animals, and occludes the effect of pmk-3 mutations when introduced into pmk-3 mutants. By contrast, RAB-5(GTP, which increases endocytosis, suppresses the effect of pmk-3 mutations, mimics the effect of rpm-1 mutations, and occludes the effect of rpm-1 mutations. Our findings indicate a novel specialized role for RPM-1 and PMK-3/p38 MAPK in regulating the endosomal trafficking of AMPARs at central synapses.

  9. Cytosolic PLA2(alpha) activation in Purkinje neurons and its role in AMPA-receptor trafficking.

    Science.gov (United States)

    Mashimo, Masato; Hirabayashi, Tetsuya; Murayama, Toshihiko; Shimizu, Takao

    2008-09-15

    Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) selectively releases arachidonic acid from membrane phospholipids and has been proposed to be involved in the induction of long-term depression (LTD), a form of synaptic plasticity in the cerebellum. This enzyme requires two events for its full activation: Ca(2+)-dependent translocation from the cytosol to organelle membranes in order to access phospholipids as substrates, and phosphorylation by several kinases. However, the subcellular distribution and activation of cPLA(2)alpha in Purkinje cells and the role of arachidonic acid in cerebellar LTD have not been fully elucidated. In cultured Purkinje cells, stimulation of AMPA receptors, but not metabotropic glutamate receptors, triggered translocation of cPLA(2)alpha to the somatic and dendritic Golgi compartments. This translocation required Ca(2+) influx through P-type Ca(2+) channels. AMPA plus PMA, a chemical method for inducing LTD, released arachidonic acid via phosphorylation of cPLA(2)alpha. AMPA plus PMA induced a decrease in surface GluR2 for more than 2 hours. Interestingly, this reduction was occluded by a cPLA(2)alpha-specific inhibitor. Furthermore, PMA plus arachidonic acid caused the prolonged internalization of GluR2 without activating AMPA receptors. These results suggest that cPLA(2)alpha regulates the persistent decrease in the expression of AMPA receptors, underscoring the role of cPLA(2)alpha in cerebellar LTD. PMID:18713832

  10. AMPA receptor trafficking and the mechanisms underlying synaptic plasticity and cognitive aging

    OpenAIRE

    Henley JM; Wilkinson KA

    2013-01-01

    Even in healthy individuals there is an inexorable agerelated decline in cognitive function. This is due, in large part, to reduced synaptic plasticity caused by changes in the molecular composition of the postsynaptic membrane. AMPA receptors (AMPARs) are glutamate-gated cation channels that mediate the overwhelming majority of fast excitatory transmission in the brain. Changes in AMPAR number and/or function are a core feature of synaptic plasticity and age-related cognitive decline, AMPARs...

  11. Regulation of AMPA receptors in spinal nociception

    Directory of Open Access Journals (Sweden)

    Lin Qing

    2010-01-01

    Full Text Available Abstract The functional properties of α-amino-3-hydroxy-5-methy-4-isoxazole propionate (AMPA receptors in different brain regions, such as hippocampus and cerebellum, have been well studied in vitro and in vivo. The AMPA receptors present a unique characteristic in the mechanisms of subunit regulation during LTP (long-term potentiation and LTD (long-term depression, which are involved in the trafficking, altered composition and phosphorylation of AMPA receptor subunits. Accumulated data have demonstrated that spinal AMPA receptors play a critical role in the mechanism of both acute and persistent pain. However, less is known about the biochemical regulation of AMPA receptor subunits in the spinal cord in response to painful stimuli. Recent studies have shown that some important regulatory processes, such as the trafficking of AMPA receptor subunit, subunit compositional changes, phosphorylation of AMPA receptor subunits, and their interaction with partner proteins may contribute to spinal nociceptive transmission. Of all these regulation processes, the phosphorylation of AMPA receptor subunits is the most important since it may trigger or affect other cellular processes. Therefore, these study results may suggest an effective strategy in developing novel analgesics targeting AMPA receptor subunit regulation that may be useful in treating persistent and chronic pain without unacceptable side effects in the clinics.

  12. AMPA receptor trafficking in inflammation-induced dorsal horn central sensitization

    Institute of Scientific and Technical Information of China (English)

    Yuan-Xiang Tao

    2012-01-01

    Activity-dependent postsynaptic receptor trafficking is critical for long-term synaptic plasticity in the brain,but it is unclear whether this mechanism actually mediates the spinal cord dorsal horn central sensitization (a specific form of synaptic plasticity) that is associated with persistent pain.Recent studies have shown that peripheral inflammation drives changes in α-amino-3-hydroxy-5-methy1-4-isoxazolepropionic acid receptor (AMPAR) subunit trafficking in the dorsal horn and that such changes contribute to the hypersensitivity that underlies persistent pain.Here,we review current evidence to illustrate how spinal cord AMPARs participate in the dorsal horn central sensitization associated with persistent pain.Understanding these mechanisms may allow the development of novel therapeutic strategies for treating persistent pain.

  13. 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. ...... polyamine toxins antagonize the AMPA receptor ion channel and provide the basis for rational development of uncompetitive antagonists of AMPA receptors....

  14. Oligomeric amyloid-{beta} inhibits the proteolytic conversion of brain-derived neurotrophic factor (BDNF), AMPA receptor trafficking, and classical conditioning.

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    Zheng, Zhaoqing; Sabirzhanov, Boris; Keifer, Joyce

    2010-11-01

    Amyloid-β (Aβ) peptide is thought to have a significant role in the progressive memory loss observed in patients with Alzheimer disease and inhibits synaptic plasticity in animal models of learning. We previously demonstrated that brain-derived neurotrophic factor (BDNF) is critical for synaptic AMPA receptor delivery in an in vitro model of eyeblink classical conditioning. Here, we report that acquisition of conditioned responses was significantly attenuated by bath application of oligomeric (200 nm), but not fibrillar, Aβ peptide. Western blotting revealed that BDNF protein expression during conditioning is significantly reduced by treatment with oligomeric Aβ, as were phosphorylation levels of cAMP-response element-binding protein (CREB), Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV), and ERK. However, levels of PKA and PKCζ/λ were unaffected, as was PDK-1. Protein localization studies using confocal imaging indicate that oligomeric Aβ, but not fibrillar or scrambled forms, suppresses colocalization of GluR1 and GluR4 AMPA receptor subunits with synaptophysin, indicating that trafficking of these subunits to synapses during the conditioning procedure is blocked. In contrast, coapplication of BDNF with oligomeric Aβ significantly reversed these findings. Interestingly, a tolloid-like metalloproteinase in turtle, tTLLs (turtle tolloid-like protein), which normally processes the precursor proBDNF into mature BDNF, was found to degrade oligomeric Aβ into small fragments. These data suggest that an Aβ-induced reduction in BDNF, perhaps due to interference in the proteolytic conversion of proBDNF to BDNF, results in inhibition of synaptic AMPA receptor delivery and suppression of the acquisition of conditioning.

  15. Excitatory synapses are stronger in the hippocampus of Rett syndrome mice due to altered synaptic trafficking of AMPA-type glutamate receptors.

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    Li, Wei; Xu, Xin; Pozzo-Miller, Lucas

    2016-03-15

    Deficits in long-term potentiation (LTP) at central excitatory synapses are thought to contribute to cognitive impairments in neurodevelopmental disorders associated with intellectual disability and autism. Using the methyl-CpG-binding protein 2 (Mecp2) knockout (KO) mouse model of Rett syndrome, we show that naïve excitatory synapses onto hippocampal pyramidal neurons of symptomatic mice have all of the hallmarks of potentiated synapses. Stronger Mecp2 KO synapses failed to undergo LTP after either theta-burst afferent stimulation or pairing afferent stimulation with postsynaptic depolarization. On the other hand, basal synaptic strength and LTP were not affected in slices from younger presymptomatic Mecp2 KO mice. Furthermore, spine synapses in pyramidal neurons from symptomatic Mecp2 KO are larger and do not grow in size or incorporate GluA1 subunits after electrical or chemical LTP. Our data suggest that LTP is occluded in Mecp2 KO mice by already potentiated synapses. The higher surface levels of GluA1-containing receptors are consistent with altered expression levels of proteins involved in AMPA receptor trafficking, suggesting previously unidentified targets for therapeutic intervention for Rett syndrome and other MECP2-related disorders.

  16. Stargazin regulates AMPA receptors trafficking-a new target for pain control%Stargazin调节使君子酸受体亚基转运和突触靶向——疼痛治疗的新靶点

    Institute of Scientific and Technical Information of China (English)

    郭瑞娟; 王云; 吴安石; 岳云

    2012-01-01

    Background α-amino-3-hydroxy-5 -methy-4-isoxazole propionate (AMPA)receptor mediates the most excitatory synaptic transmission in the central nervous system,and is involved in the pain signal transmission.As a member of trans-membrane AMPA receptor regulated protein family,Stargazin serves as a critical protein involved in the trafficking and synaptic targeting ofAMPA receptors and plays an important role in the AMPA receptor-mediated pain. Objective In this review,we will bring together the evidence that Stargazin controls the AMPA receptor subunits trafficking,synaptic insertion and regulates pain signal transmission.Content Stargazin is responsible for the AMPA receptor subunits trafficking into cellular membrane.The interaction between Stargazin and postsynaptic density-95 (PSD-95) controls the synaptic insertion of AMPA receptor subunits.The phosphrylation of Stargazin affects the interaction with PSD-95.Therefore,Stargazin may be implicated in pain transmission via regulating AMPA receptor function. Trend Downregulation of Stargazin expression or disrupting the postsynaptic interaction between stargazin and PSD-95 may be a new approach for pain control and deserves further investigation.%背景 使君子酸(α-amino-3 -hydroxy-5 -methy-4-isoxazole propionate,AMPA)受体是中介中枢神经系统兴奋性突触传递的主要受体,参与疼痛信号传递.Stargazin蛋白是一种AMPA受体调节蛋白,在AMPA受体中介的疼痛信号传递中扮演重要角色.目的 对Stargazin蛋白调节AMPA受体亚基在胞浆胞膜中的转运作用及与疼痛的关系作用进行回顾与总结.内容 Stargazin蛋白可调节AMPA受体不同亚基在胞浆胞膜转运,并通过与突触后膜致密蛋白-95 (postsynaptic density-95,PSD-95)的相互作用,促进AMPA受体亚基突触靶向;Stargazin还通过C末端自身磷酸化修饰改变与PSD-95蛋白相互作用的强度,控制AMPA受体的突触靶向.Stargazin通过调节AMPA受

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

    NARCIS (Netherlands)

    Esteves da Silva, Marta; Adrian, Max; Schätzle, Philipp; Lipka, Joanna; Watanabe, Takuya; Cho, Sukhee; Futai, Kensuke; Wierenga, Corette J; Kapitein, Lukas C; Hoogenraad, Casper C

    2015-01-01

    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 en

  18. AMPA receptor ligands

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Mellor, Ian

    2004-01-01

    polyamines are known to modulate the function of these receptors in vivo. In this study, recent developments in the medicinal chemistry of polyamine-based ligands are given, particularly focusing on the use of solid-phase synthesis (SPS) as a tool for the facile generation of libraries of polyamine toxin...

  19. 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......]AMPA radioligand binding experiments. (S)-4-bromohomoibotenic acid (BrHIBO) exhibited a 126-fold selectivity for GluR1o compared to GluR3o. Xenopus laevis oocytes were used to express functional homomeric and heteromeric recombinant AMPA-R and to determine BrHIBO potency (EC50) at these channels. (R......,S)-BrHIBO exhibited a 37-fold selectivity range amongst the AMPA-R. It is hoped that BrHIBO can be used as a lead structure for the development of other subtype-selective compounds....

  20. Direct imaging of lateral movements of AMPA receptors inside synapses

    CERN Document Server

    Tardin, Catherine; Bats, Cécile; Lounis, Brahim; Choquet, Daniel

    2003-01-01

    Trafficking of AMPA receptors in and out of synapses is crucial for synaptic plasticity. Previous studies have focused on the role of endo/exocytosis processes or that of lateral diffusion of extra-synaptic receptors. We have now directly imaged AMPAR movements inside and outside synapses of live neurons using single-molecule fluorescence microscopy. Inside individual synapses, we found immobile and mobile receptors, which display restricted diffusion. Extra-synaptic receptors display free diffusion. Receptors could also exchange between these membrane compartments through lateral diffusion. Glutamate application increased both receptor mobility inside synapses and the fraction of mobile receptors present in a juxtasynaptic region. Block of inhibitory transmission to favor excitatory synaptic activity induced a transient increase in the fraction of mobile receptors and a decrease in the proportion of juxtasynaptic receptors. Altogether, our data show that rapid exchange of receptors between a synaptic and ext...

  1. Discovery of the First α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptor Antagonist Dependent upon Transmembrane AMPA Receptor Regulatory Protein (TARP) γ-8.

    Science.gov (United States)

    Gardinier, Kevin M; Gernert, Douglas L; Porter, Warren J; Reel, Jon K; Ornstein, Paul L; Spinazze, Patrick; Stevens, F Craig; Hahn, Patric; Hollinshead, Sean P; Mayhugh, Daniel; Schkeryantz, Jeff; Khilevich, Albert; De Frutos, Oscar; Gleason, Scott D; Kato, Akihiko S; Luffer-Atlas, Debra; Desai, Prashant V; Swanson, Steven; Burris, Kevin D; Ding, Chunjin; Heinz, Beverly A; Need, Anne B; Barth, Vanessa N; Stephenson, Gregory A; Diseroad, Benjamin A; Woods, Tim A; Yu, Hong; Bredt, David; Witkin, Jeffrey M

    2016-05-26

    Transmembrane AMPA receptor regulatory proteins (TARPs) are a family of scaffolding proteins that regulate AMPA receptor trafficking and function. TARP γ-8 is one member of this family and is highly expressed within the hippocampus relative to the cerebellum. A selective TARP γ-8-dependent AMPA receptor antagonist (TDAA) is an innovative approach to modulate AMPA receptors in specific brain regions to potentially increase the therapeutic index relative to known non-TARP-dependent AMPA antagonists. We describe here, for the first time, the discovery of a noncompetitive AMPA receptor antagonist that is dependent on the presence of TARP γ-8. Three major iteration cycles were employed to improve upon potency, CYP1A2-dependent challenges, and in vivo clearance. An optimized molecule, compound (-)-25 (LY3130481), was fully protective against pentylenetetrazole-induced convulsions in rats without the motor impairment associated with non-TARP-dependent AMPA receptor antagonists. Compound (-)-25 could be utilized to provide proof of concept for antiepileptic efficacy with reduced motor side effects in patients. PMID:27067148

  2. Extensive phosphorylation of AMPA receptors in neurons.

    Science.gov (United States)

    Diering, Graham H; Heo, Seok; Hussain, Natasha K; Liu, Bian; Huganir, Richard L

    2016-08-16

    Regulation of AMPA receptor (AMPAR) function is a fundamental mechanism controlling synaptic strength during long-term potentiation/depression and homeostatic scaling. AMPAR function and membrane trafficking is controlled by protein-protein interactions, as well as by posttranslational modifications. Phosphorylation of the GluA1 AMPAR subunit at S845 and S831 play especially important roles during synaptic plasticity. Recent controversy has emerged regarding the extent to which GluA1 phosphorylation may contribute to synaptic plasticity. Here we used a variety of methods to measure the population of phosphorylated GluA1-containing AMPARs in cultured primary neurons and mouse forebrain. Phosphorylated GluA1 represents large fractions from 12% to 50% of the total population under basal and stimulated conditions in vitro and in vivo. Furthermore, a large fraction of synapses are positive for phospho-GluA1-containing AMPARs. Our results support the large body of research indicating a prominent role of GluA1 phosphorylation in synaptic plasticity. PMID:27482106

  3. Synaptic plasticity, AMPA-R trafficking, and Ras-MAPK signaling

    Institute of Scientific and Technical Information of China (English)

    Yun GU; Ruth L STORNETTA

    2007-01-01

    Synaptic modification of transmission is a general phenomenon expressed at al-most every excitatory synapse in the mammalian brain. Over the last three decades,much has been discovered about the cellular, synaptic, molecular, and signalingmechanisms responsible for controlling synaptic transmission and plasticity. Here,we present a brief review of these mechanisms with emphasis on the currentunderstanding of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid recep-tor (AMPA-R) trafficking and Ras-mitogen-activated protein kinase (MAPK)signaling events involved in controlling synaptic transmission.

  4. AMPA receptor inhibition by synaptically released zinc.

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    Kalappa, Bopanna I; Anderson, Charles T; Goldberg, Jacob M; Lippard, Stephen J; Tzounopoulos, Thanos

    2015-12-22

    The vast amount of fast excitatory neurotransmission in the mammalian central nervous system is mediated by AMPA-subtype glutamate receptors (AMPARs). As a result, AMPAR-mediated synaptic transmission is implicated in nearly all aspects of brain development, function, and plasticity. Despite the central role of AMPARs in neurobiology, the fine-tuning of synaptic AMPA responses by endogenous modulators remains poorly understood. Here we provide evidence that endogenous zinc, released by single presynaptic action potentials, inhibits synaptic AMPA currents in the dorsal cochlear nucleus (DCN) and hippocampus. Exposure to loud sound reduces presynaptic zinc levels in the DCN and abolishes zinc inhibition, implicating zinc in experience-dependent AMPAR synaptic plasticity. Our results establish zinc as an activity-dependent, endogenous modulator of AMPARs that tunes fast excitatory neurotransmission and plasticity in glutamatergic synapses.

  5. Two-stage AMPA receptor trafficking in classical conditioning and selective role for glutamate receptor subunit 4 (tGluA4) flop splice variant.

    Science.gov (United States)

    Zheng, Zhaoqing; Sabirzhanov, Boris; Keifer, Joyce

    2012-07-01

    Previously, we proposed a two-stage model for an in vitro neural correlate of eyeblink classical conditioning involving the initial synaptic incorporation of glutamate receptor A1 (GluA1)-containing α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid type receptors (AMPARs) followed by delivery of GluA4-containing AMPARs that support acquisition of conditioned responses. To test specific elements of our model for conditioning, selective knockdown of GluA4 AMPAR subunits was used using small-interfering RNAs (siRNAs). Recently, we sequenced and characterized the GluA4 subunit and its splice variants from pond turtles, Trachemys scripta elegans (tGluA4). Analysis of the relative abundance of mRNA expression by real-time RT-PCR showed that the flip/flop variants of tGluA4, tGluA4c, and a novel truncated variant tGluA4trc1 are major isoforms in the turtle brain. Here, transfection of in vitro brain stem preparations with anti-tGluA4 siRNA suppressed conditioning, tGluA4 mRNA and protein expression, and synaptic delivery of tGluA4-containing AMPARs but not tGluA1 subunits. Significantly, transfection of abducens motor neurons by nerve injections of tGluA4 flop rescue plasmid prior to anti-tGluA4 siRNA application restored conditioning and synaptic incorporation of tGluA4-containing AMPARs. In contrast, treatment with rescue plasmids for tGluA4 flip or tGluA4trc1 failed to rescue conditioning. Finally, treatment with a siRNA directed against GluA1 subunits inhibited conditioning and synaptic delivery of tGluA1-containing AMPARs and importantly, those containing tGluA4. These data strongly support our two-stage model of conditioning and our hypothesis that synaptic incorporation of tGluA4-containing AMPARs underlies the acquisition of in vitro classical conditioning. Furthermore, they suggest that tGluA4 flop may have a critical role in conditioning mechanisms compared with the other tGluA4 splice variants.

  6. Perampanel inhibition of AMPA receptor currents in cultured hippocampal neurons.

    Directory of Open Access Journals (Sweden)

    Chao-Yin Chen

    Full Text Available Perampanel is an aryl substituted 2-pyridone AMPA receptor antagonist that was recently approved as a treatment for epilepsy. The drug potently inhibits AMPA receptor responses but the mode of block has not been characterized. Here the action of perampanel on AMPA receptors was investigated by whole-cell voltage-clamp recording in cultured rat hippocampal neurons. Perampanel caused a slow (τ∼1 s at 3 µM, concentration-dependent inhibition of AMPA receptor currents evoked by AMPA and kainate. The rates of block and unblock of AMPA receptor currents were 1.5×105 M-1 s-1 and 0.58 s-1, respectively. Perampanel did not affect NMDA receptor currents. The extent of block of non-desensitizing kainate-evoked currents (IC50, 0.56 µM was similar at all kainate concentrations (3-100 µM, demonstrating a noncompetitive blocking action. Parampanel did not alter the trajectory of AMPA evoked currents indicating that it does not influence AMPA receptor desensitization. Perampanel is a selective negative allosteric AMPA receptor antagonist of high-affinity and slow blocking kinetics.

  7. Postsynaptic VAMP/Synaptobrevin Facilitates Differential Vesicle Trafficking of GluA1 and GluA2 AMPA Receptor Subunits.

    Science.gov (United States)

    Hussain, Suleman; Davanger, Svend

    2015-01-01

    Vertebrate organisms adapt to a continuously changing environment by regulating the strength of synaptic connections between brain cells. Excitatory synapses are believed to increase their strength by vesicular insertion of transmitter glutamate receptors into the postsynaptic plasma membrane. These vesicles, however, have never been demonstrated or characterized. For the first time, we show the presence of small vesicles in postsynaptic spines, often closely adjacent to the plasma membrane and PSD (postsynaptic density). We demonstrate that they harbor vesicle-associated membrane protein 2 (VAMP2/synaptobrevin-2) and glutamate receptor subunit 1 (GluA1). Disrupting VAMP2 by tetanus toxin treatment reduces the concentration of GluA1 in the postsynaptic plasma membrane. GluA1/VAMP2-containing vesicles, but not GluA2/VAMP2-vesicles, are concentrated in postsynaptic spines relative to dendrites. Our results indicate that small postsynaptic vesicles containing GluA1 are inserted directly into the spine plasma membrane through a VAMP2-dependent mechanism.

  8. Postsynaptic VAMP/Synaptobrevin Facilitates Differential Vesicle Trafficking of GluA1 and GluA2 AMPA Receptor Subunits.

    Directory of Open Access Journals (Sweden)

    Suleman Hussain

    Full Text Available Vertebrate organisms adapt to a continuously changing environment by regulating the strength of synaptic connections between brain cells. Excitatory synapses are believed to increase their strength by vesicular insertion of transmitter glutamate receptors into the postsynaptic plasma membrane. These vesicles, however, have never been demonstrated or characterized. For the first time, we show the presence of small vesicles in postsynaptic spines, often closely adjacent to the plasma membrane and PSD (postsynaptic density. We demonstrate that they harbor vesicle-associated membrane protein 2 (VAMP2/synaptobrevin-2 and glutamate receptor subunit 1 (GluA1. Disrupting VAMP2 by tetanus toxin treatment reduces the concentration of GluA1 in the postsynaptic plasma membrane. GluA1/VAMP2-containing vesicles, but not GluA2/VAMP2-vesicles, are concentrated in postsynaptic spines relative to dendrites. Our results indicate that small postsynaptic vesicles containing GluA1 are inserted directly into the spine plasma membrane through a VAMP2-dependent mechanism.

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    , and the rat cortical wedge preparation. CIP-A showed a good affinity for both 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) and kainic acid (KAIN) receptors. These results were confirmed in the cortical slice model where CIP-A displayed an EC(50) value very close to that of AMPA...

  10. AMPA Receptors Commandeer an Ancient Cargo Exporter for Use as an Auxiliary Subunit for Signaling

    OpenAIRE

    Nadine Harmel; Barbara Cokic; Gerd Zolles; Henrike Berkefeld; Veronika Mauric; Bernd Fakler; Valentin Stein; Nikolaj Klöcker

    2012-01-01

    Fast excitatory neurotransmission in the mammalian central nervous system is mainly mediated by ionotropic glutamate receptors of the AMPA subtype (AMPARs). AMPARs are protein complexes of the pore-lining alpha-subunits GluA1-4 and auxiliary beta-subunits modulating their trafficking and gating. By a proteomic approach, two homologues of the cargo exporter cornichon, CNIH-2 and CNIH-3, have recently been identified as constituents of native AMPARs in mammalian brain. In heterologous reconstit...

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 切口痛大鼠脊髓背角GluR1-AMPA受体和GluR2-AMPA受体胞浆至胞膜转运的变化%Changes in trafficking of GluR1-containing AMPA receptor and GluR2-containing AMPA receptor from cytoplasm to cell membrane in spinal dorsal horn in a rat model of incisional pain

    Institute of Scientific and Technical Information of China (English)

    郭瑞娟; 王云; 时蓉; 吴安石; 岳云

    2012-01-01

    Objective To investigate the changes in trafficking of GluRl-containing AMPA (GluR1-AMPA) receptor and GluR2-AMPA receptor from cytoplasm to cell membrane in the spinal cord dorsal horn in a rat model of incisional pain.Methods Thirty-two adult male SD rats aged 6-8 weeks weighing 280-300 g were randomly divided into 2 groups:control group (group C,n =8) and incisional pain group (group Ⅰ,n =24).An 1 cm long incision was made in the plautar surface of right hindpaw according to Brennan et al.in group Ⅰ.Cumulative pain score (CPS) and paw-withdrawal threshold to yon Frey stimuli (PWT) were measured at 3 h and day 1 and 3 afar incision ( T1,2,3 ).The animals were sacrificed after pain behavior assessment.Their lumbar segments of the spinal cord (L3-6) were removed.The expression of GluR1 and GluR2 in cell membrane and cytoplasm in spinal cord dorsal horn was determined by Western blot analysis.The co-expression of Stargazing with GluR1 and GluR2 in the spinal cord dorsal horn was examined by co-immuno-precipitation.Results The CPS was increased and PWT decreased; the GluR1 expression in cytoplasm was decreased while the expression of GluR1 in cell membrane and the co-expression of Stargazing with GluR1 were up-regulated in group Ⅰ as compared with group C.There was no significant change in the expression of GluR2 in cytoplasm and cell membrane and the co-expression of Stargazing with GluR2 in group Ⅰ as compared with group C.Conclusion GluR1-AMPA receptor transfers from cytoplasm to cell membrane but GluR2-AMPA receptor does not in rats with incisional pain.%目的 探讨切口痛大鼠脊髓背角含谷氨酸受体1亚基的使君子酸(GluR1-AMPA)受体和含谷氨酸受体2亚基的使君子酸(GluR2-AMPA)受体胞浆至胞膜转运的变化.方法 成年雄性清洁级SD大鼠32只,体重280~ 300 g,6~8周龄,采用随机数表法,将其随机分为2组:正常对照组(C组,n=8)和切口痛组(Ⅰ组,n=24).Ⅰ组大鼠制作右足底

  13. Mechanism of Positive Allosteric Modulators Acting on AMPA Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Jin,R.; Clark, S.; Weeks, A.; Dudman, J.; Gouaux, E.; Partin, K.

    2005-01-01

    Ligand-gated ion channels involved in the modulation of synaptic strength are the AMPA, kainate, and NMDA glutamate receptors. Small molecules that potentiate AMPA receptor currents relieve cognitive deficits caused by neurodegenerative diseases such as Alzheimer's disease and show promise in the treatment of depression. Previously, there has been limited understanding of the molecular mechanism of action for AMPA receptor potentiators. Here we present cocrystal structures of the glutamate receptor GluR2 S1S2 ligand-binding domain in complex with aniracetam [1-(4-methoxybenzoyl)-2-pyrrolidinone] or CX614 (pyrrolidino-1, 3-oxazino benzo-1, 4-dioxan-10-one), two AMPA receptor potentiators that preferentially slow AMPA receptor deactivation. Both potentiators bind within the dimer interface of the nondesensitized receptor at a common site located on the twofold axis of molecular symmetry. Importantly, the potentiator binding site is adjacent to the 'hinge' in the ligand-binding core 'clamshell' that undergoes conformational rearrangement after glutamate binding. Using rapid solution exchange, patch-clamp electrophysiology experiments, we show that point mutations of residues that interact with potentiators in the cocrystal disrupt potentiator function. We suggest that the potentiators slow deactivation by stabilizing the clamshell in its closed-cleft, glutamate-bound conformation.

  14. Ubiquitin-dependent trafficking and turnover of ionotropic glutamate receptors

    Directory of Open Access Journals (Sweden)

    Marisa S Goo

    2015-10-01

    Full Text Available Changes in synaptic strength underlie the basis of learning and memory and are controlled, in part, by the insertion or removal of AMPA-type glutamate receptors at the postsynaptic membrane of excitatory synapses. Once internalized, these receptors may be recycled back to the plasma membrane by subunit-specific interactions with other proteins or by post-translational modifications such as phosphorylation. Alternatively, these receptors may be targeted for destruction by multiple degradation pathways in the cell. Ubiquitination, another post-translational modification, has recently emerged as a key signal that regulates the recycling and trafficking of glutamate receptors. In this review, we will discuss recent findings on the role of ubiquitination in the trafficking and turnover of ionotropic glutamate receptors and plasticity of excitatory synapses.

  15. 3-Substituted phenylalanines as selective AMPA- and kainate receptor ligands

    DEFF Research Database (Denmark)

    Szymanska, Ewa; Pickering, Darryl S; Nielsen, Birgitte;

    2009-01-01

    On the basis of X-ray structures of ionotropic glutamate receptor constructs in complex with amino acid-based AMPA and kainate receptor antagonists, a series of rigid as well as flexible biaromatic alanine derivatives carrying selected hydrogen bond acceptors and donors have been synthesized in o...

  16. Effects of Exposure to Aluminum on Long-term Potentiation and AMPA Receptor Subunits in Ratsin vivo

    Institute of Scientific and Technical Information of China (English)

    SONG Jing; LIU Ying; ZHANG Hui Fang; ZHANG Qin Li; NIU Qiao

    2014-01-01

    ObjectiveTo explore the effects of exposure to aluminum(Al) on long-term potentiation(LTP) and AMPA receptor subunits in rats in vivo. MethodsDifferent dosages of aluminum-maltolate complex[Al(mal)3] were given to rats via acute intracerebroventricular (i.c.v.)injection and subchronic intraperitoneal (i.p.) injection. Following Al exposure, the hippocampal LTP were recorded by field potentiation techniquein vivo and the expression of AMPAR subunit proteins (GluR1 and GluR2) in both total and membrane-enriched extracts from the CA1 area of rat hippocampus were detected by Western blot assay. ResultsAcute Al treatment produced dose-dependent suppression of LTP in the rat hippocampus and dose-dependent decreases of GluR1and GluR2in membrane extracts; however, no similar changes were found in the total cell extracts, which suggests decreased trafficking of AMPA receptor subunits from intracellular pools to synaptic sites in the hippocampus. Thedose-dependent suppressive effects on LTP and the expression of AMPA receptor subunits both in the membrane and in total extracts were found after subchronic Al treatment, indicating a decrease in AMPA receptor subunit trafficking from intracellular poolsto synaptic sites and an additional reduction in the expression of the subunits. ConclusionAl(mal)3obviously and dose-dependently suppressed LTP in the rat hippocampal CA1 region in vivo, and this suppression may be related to both trafficking and decreases in the expression of AMPA receptor subunit proteins. However, the mechanisms underlying these observations need further investigation.

  17. Are AMPA receptor positive allosteric modulators potential pharmacotherapeutics for addiction?

    Science.gov (United States)

    Watterson, Lucas R; Olive, M Foster

    2013-01-01

    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. PMID:24380895

  18. S-SCAM/MAGI-2 is an essential synaptic scaffolding molecule for the GluA2-containing maintenance pool of AMPA receptors

    OpenAIRE

    Danielson, Eric; Zhang, Nanyan; Metallo, Jacob; Kaleka, Kanwardeep; Shin, Seung Min; Gerges, Nashaat; Lee, Sang H.

    2012-01-01

    Synaptic plasticity, the cellular basis of learning and memory, involves the dynamic trafficking of AMPA receptors (AMPARs) into and out of synapses. One of the remaining key unanswered aspects of AMPAR trafficking is the mechanism by which synaptic strength is preserved in spite of protein turnover. In particular, the identity of AMPAR scaffolding molecule(s) involved in the maintenance of GluA2-containing AMPARs is completely unknown. Here we report that Synaptic scaffolding molecule (S-SCA...

  19. AMPA receptor potentiation can prevent ethanol-induced intoxication.

    Science.gov (United States)

    Jones, Nicholas; Messenger, Marcus J; O'Neill, Michael J; Oldershaw, Anna; Gilmour, Gary; Simmons, Rosa M A; Iyengar, Smriti; Libri, Vincenzo; Tricklebank, Mark; Williams, Steve C R

    2008-06-01

    We present a substantial series of behavioral and imaging experiments, which demonstrate, for the first time, that increasing AMPA receptor-mediated neurotransmission via administration of potent and selective biarylsulfonamide AMPA potentiators LY404187 and LY451395 reverses the central effects of an acutely intoxicating dose of ethanol in the rat. Using pharmacological magnetic resonance imaging (phMRI), we observed that LY404187 attenuated ethanol-induced reductions in blood oxygenation level dependent (BOLD) in the anesthetized rat brain. A similar attenuation was apparent when measuring local cerebral glucose utilization (LCGU) via C14-2-deoxyglucose autoradiography in freely moving conscious rats. Both LY404187 and LY451395 significantly and dose-dependently reversed ethanol-induced deficits in both motor coordination and disruptions in an operant task where animals were trained to press a lever for food reward. Both prophylactic and acute intervention treatment with LY404187 reversed ethanol-induced deficits in motor coordination. Given that LY451395 and related AMPA receptor potentiators/ampakines are tolerated in both healthy volunteers and elderly patients, these data suggest that such compounds may form a potential management strategy for acute alcohol intoxication.

  20. Seizure control by decanoic acid through direct AMPA receptor inhibition.

    Science.gov (United States)

    Chang, Pishan; Augustin, Katrin; Boddum, Kim; Williams, Sophie; Sun, Min; Terschak, John A; Hardege, Jörg D; Chen, Philip E; Walker, Matthew C; Williams, Robin S B

    2016-02-01

    The medium chain triglyceride ketogenic diet is an established treatment for drug-resistant epilepsy that increases plasma levels of decanoic acid and ketones. Recently, decanoic acid has been shown to provide seizure control in vivo, yet its mechanism of action remains unclear. Here we show that decanoic acid, but not the ketones β-hydroxybutryate or acetone, shows antiseizure activity in two acute ex vivo rat hippocampal slice models of epileptiform activity. To search for a mechanism of decanoic acid, we show it has a strong inhibitory effect on excitatory, but not inhibitory, neurotransmission in hippocampal slices. Using heterologous expression of excitatory ionotropic glutamate receptor AMPA subunits in Xenopus oocytes, we show that this effect is through direct AMPA receptor inhibition, a target shared by a recently introduced epilepsy treatment perampanel. Decanoic acid acts as a non-competitive antagonist at therapeutically relevant concentrations, in a voltage- and subunit-dependent manner, and this is sufficient to explain its antiseizure effects. This inhibitory effect is likely to be caused by binding to sites on the M3 helix of the AMPA-GluA2 transmembrane domain; independent from the binding site of perampanel. Together our results indicate that the direct inhibition of excitatory neurotransmission by decanoic acid in the brain contributes to the anti-convulsant effect of the medium chain triglyceride ketogenic diet. PMID:26608744

  1. 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-isoxa...

  2. Elucidation of AMPA receptor-stargazin complexes by cryo-electron microscopy.

    Science.gov (United States)

    Twomey, Edward C; Yelshanskaya, Maria V; Grassucci, Robert A; Frank, Joachim; Sobolevsky, Alexander I

    2016-07-01

    AMPA-subtype ionotropic glutamate receptors (AMPARs) mediate fast excitatory neurotransmission and contribute to high cognitive processes such as learning and memory. In the brain, AMPAR trafficking, gating, and pharmacology is tightly controlled by transmembrane AMPAR regulatory proteins (TARPs). Here, we used cryo-electron microscopy to elucidate the structural basis of AMPAR regulation by one of these auxiliary proteins, TARP γ2, or stargazin (STZ). Our structures illuminate the variable interaction stoichiometry of the AMPAR-TARP complex, with one or two TARP molecules binding one tetrameric AMPAR. Analysis of the AMPAR-STZ binding interfaces suggests that electrostatic interactions between the extracellular domains of AMPAR and STZ play an important role in modulating AMPAR function through contact surfaces that are conserved across AMPARs and TARPs. We propose a model explaining how TARPs stabilize the activated state of AMPARs and how the interactions between AMPARs and their auxiliary proteins control fast excitatory synaptic transmission. PMID:27365450

  3. AMPA receptor pHluorin-GluA2 reports NMDA receptor-induced intracellular acidification in hippocampal neurons

    DEFF Research Database (Denmark)

    Rathje, Mette; Fang, Huaqiang; Bachman, Julia L;

    2013-01-01

    NMDA receptor activation promotes endocytosis of AMPA receptors, which is an important mechanism underlying long-term synaptic depression. The pH-sensitive GFP variant pHluorin fused to the N terminus of GluA2 (pH-GluA2) has been used to assay NMDA-mediated AMPA receptor endocytosis and recycling...

  4. 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

    -methyl-4-isoxazolyl)propionic acid (AMPA) receptor subtype of ionotropic Glu receptors in the presence or absence of an agonist has provided important information about ligand-receptor interaction mechanisms. The availability of these binding domain crystal structures has formed the basis for rational...... design of ligands, especially for the AMPA and kainate subtypes of ionotropic Glu receptors. This mini-review will focus on structure-activity relationships on AMPA and kainate receptor agonists with special emphasis on stereochemical and three-dimensional aspects....

  5. Rational Design of a Novel AMPA Receptor Modulator through a Hybridization Approach

    Science.gov (United States)

    2015-01-01

    The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are a family of glutamate ion channels of considerable interest in excitatory neurotransmission and associated disease processes. Here, we demonstrate how exploitation of the available X-ray crystal structure of the receptor ligand binding domain enabled the development of a new class of AMPA receptor positive allosteric modulators (7) through hybridization of known ligands (5 and 6), leading to a novel chemotype with promising pharmacological properties. PMID:25893038

  6. Modulation of glutamat AMPA receptors by adenosine, in physiological and hypoxic/ischemic conditions

    OpenAIRE

    Dias, Raquel Alice da Silva Baptista, 1983-

    2011-01-01

    Tese de doutoramento, Ciências Biomédicas (Neurociências), Universidade de Lisboa, Faculdade de Medicina, 2011 Most of the fast excitatory transmission in the brain is conveyed by ionotropic glutamate a-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA) receptors, formed by tetrameric assemblies of different subunit (GluR1-GluR4) composition. Modulation of AMPA receptors enables profound changes in synaptic efficiency, underlying the maturation of neuronal networks t...

  7. Structural and pharmacological characterization of phenylalanine-based AMPA receptor antagonists at kainate receptors

    DEFF Research Database (Denmark)

    Venskutonyte, Raminta; Frydenvang, Karla; Valadés, Elena Antón;

    2012-01-01

    . A new series of phenylalanine derivatives that target iGluRs was reported to bind AMPA receptors. Herein we report our studies of these compounds at the kainate receptors GluK1-3. Several compounds bind with micromolar affinity at GluK1 and GluK3, but do not bind GluK2. The crystal structure of the most...

  8. Dynamic Regulation of N-Methyl-d-aspartate (NMDA) and α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors by Posttranslational Modifications.

    Science.gov (United States)

    Lussier, Marc P; Sanz-Clemente, Antonio; Roche, Katherine W

    2015-11-27

    Many molecular mechanisms underlie the changes in synaptic glutamate receptor content that are required by neuronal networks to generate cellular correlates of learning and memory. During the last decade, posttranslational modifications have emerged as critical regulators of synaptic transmission and plasticity. Notably, phosphorylation, ubiquitination, and palmitoylation control the stability, trafficking, and synaptic expression of glutamate receptors in the central nervous system. In the current review, we will summarize some of the progress made by the neuroscience community regarding our understanding of phosphorylation, ubiquitination, and palmitoylation of the NMDA and AMPA subtypes of glutamate receptors. PMID:26453298

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

    Directory of Open Access Journals (Sweden)

    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. AMPA receptors commandeer an ancient cargo exporter for use as an auxiliary subunit for signaling.

    Directory of Open Access Journals (Sweden)

    Nadine Harmel

    Full Text Available Fast excitatory neurotransmission in the mammalian central nervous system is mainly mediated by ionotropic glutamate receptors of the AMPA subtype (AMPARs. AMPARs are protein complexes of the pore-lining α-subunits GluA1-4 and auxiliary β-subunits modulating their trafficking and gating. By a proteomic approach, two homologues of the cargo exporter cornichon, CNIH-2 and CNIH-3, have recently been identified as constituents of native AMPARs in mammalian brain. In heterologous reconstitution experiments, CNIH-2 promotes surface expression of GluAs and modulates their biophysical properties. However, its relevance in native AMPAR physiology remains controversial. Here, we have studied the role of CNIH-2 in GluA processing both in heterologous cells and primary rat neurons. Our data demonstrate that CNIH-2 serves an evolutionarily conserved role as a cargo exporter from the endoplasmic reticulum (ER. CNIH-2 cycles continuously between ER and Golgi complex to pick up cargo protein in the ER and then to mediate its preferential export in a coat protein complex (COP II dependent manner. Interaction with GluA subunits breaks with this ancestral role of CNIH-2 confined to the early secretory pathway. While still taking advantage of being exported preferentially from the ER, GluAs recruit CNIH-2 to the cell surface. Thus, mammalian AMPARs commandeer CNIH-2 for use as a bona fide auxiliary subunit that is able to modify receptor signaling.

  11. 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...

  12. Shisa6 traps AMPA receptors at postsynaptic sites and prevents their desensitization during synaptic activity.

    Science.gov (United States)

    Klaassen, Remco V; Stroeder, Jasper; Coussen, Françoise; Hafner, Anne-Sophie; Petersen, Jennifer D; Renancio, Cedric; Schmitz, Leanne J M; Normand, Elisabeth; Lodder, Johannes C; Rotaru, Diana C; Rao-Ruiz, Priyanka; Spijker, Sabine; Mansvelder, Huibert D; Choquet, Daniel; Smit, August B

    2016-03-02

    Trafficking and biophysical properties of AMPA receptors (AMPARs) in the brain depend on interactions with associated proteins. We identify Shisa6, a single transmembrane protein, as a stable and directly interacting bona fide AMPAR auxiliary subunit. Shisa6 is enriched at hippocampal postsynaptic membranes and co-localizes with AMPARs. The Shisa6 C-terminus harbours a PDZ domain ligand that binds to PSD-95, constraining mobility of AMPARs in the plasma membrane and confining them to postsynaptic densities. Shisa6 expressed in HEK293 cells alters GluA1- and GluA2-mediated currents by prolonging decay times and decreasing the extent of AMPAR desensitization, while slowing the rate of recovery from desensitization. Using gene deletion, we show that Shisa6 increases rise and decay times of hippocampal CA1 miniature excitatory postsynaptic currents (mEPSCs). Shisa6-containing AMPARs show prominent sustained currents, indicating protection from full desensitization. Accordingly, Shisa6 prevents synaptically trapped AMPARs from depression at high-frequency synaptic transmission.

  13. Natural reward experience alters AMPA and NMDA receptor distribution and function in the nucleus accumbens.

    Directory of Open Access Journals (Sweden)

    Kyle K Pitchers

    Full Text Available Natural reward and drugs of abuse converge upon the mesolimbic system which mediates motivation and reward behaviors. Drugs induce neural adaptations in this system, including transcriptional, morphological, and synaptic changes, which contribute to the development and expression of drug-related memories and addiction. Previously, it has been reported that sexual experience in male rats, a natural reward behavior, induces similar neuroplasticity in the mesolimbic system and affects natural reward and drug-related behavior. The current study determined whether sexual experience causes long-lasting changes in mating, or ionotropic glutamate receptor trafficking or function in the nucleus accumbens (NAc, following 3 different reward abstinence periods: 1 day, 1 week, or 1 month after final mating session. Male Sprague Dawley rats mated during 5 consecutive days (sexual experience or remained sexually naïve to serve as controls. Sexually experienced males displayed facilitation of initiation and performance of mating at each time point. Next, intracellular and membrane surface expression of N-methyl-D-aspartate (NMDA: NR1 subunit and α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA: GluA1, GluA2 subunits receptors in the NAc was determined using a bis(sulfosuccinimidylsuberate (BS(3 protein cross-linking assay followed by Western Blot analysis. NR1 expression was increased at 1 day abstinence both at surface and intracellular, but decreased at surface at 1 week of abstinence. GluA2 was increased intracellularly at 1 week and increased at the surface after 1 month of abstinence. Finally, whole-cell patch clamp electrophysiological recordings determined reduced AMPA/NMDA ratio of synaptic currents in NAc shell neurons following stimulation of cortical afferents in sexually experienced males after all reward abstinence periods. Together, these data show that sexual experience causes long-term alterations in glutamate receptor expression and

  14. Dual-specific Phosphatase-6 (Dusp6) and ERK Mediate AMPA Receptor-induced Oligodendrocyte Death*

    Science.gov (United States)

    Domercq, Maria; Alberdi, Elena; Sánchez-Gómez, Maria Victoria; Ariz, Usue; Pérez-Samartín, Alberto; Matute, Carlos

    2011-01-01

    Oligodendrocytes, the myelinating cells of the CNS, are highly vulnerable to glutamate excitotoxicity, a mechanism involved in tissue damage in multiple sclerosis. Thus, understanding oligodendrocyte death at the molecular level is important to develop new therapeutic approaches to treat the disease. Here, using microarray analysis and quantitative PCR, we observed that dual-specific phosphatase-6 (Dusp6), an extracellular regulated kinase-specific phosphatase, is up-regulated in oligodendrocyte cultures as well as in optic nerves after AMPA receptor activation. In turn, Dusp6 is overexpressed in optic nerves from multiple sclerosis patients before the appearance of evident damage in this structure. We further analyzed the role of Dusp6 and ERK signaling in excitotoxic oligodendrocyte death and observed that AMPA receptor activation induces a rapid increase in ERK1/2 phosphorylation. Blocking Dusp6 expression, which enhances ERK1/2 phosphorylation, significantly diminished AMPA receptor-induced oligodendrocyte death. In contrast, MAPK/ERK pathway inhibition with UO126 significantly potentiates excitotoxic oligodendrocyte death and increases cytochrome c release, mitochondrial depolarization, and mitochondrial calcium overload produced by AMPA receptor stimulation. Upstream analysis demonstrated that MAPK/ERK signaling alters AMPA receptor properties. Indeed, Dusp6 overexpression as well as incubation with UO126 produced an increase in AMPA receptor-induced inward currents and cytosolic calcium overload. Together, these data suggest that levels of phosphorylated ERK, controlled by Dusp6 phosphatase, regulate glutamate receptor permeability and oligodendroglial excitotoxicity. Therefore, targeting Dusp6 may be a useful strategy to prevent oligodendrocyte death in multiple sclerosis and other diseases involving CNS white matter. PMID:21300799

  15. Glycine Potentiates AMPA Receptor Function through Metabotropic Activation of GluN2A-Containing NMDA Receptors

    Science.gov (United States)

    Li, Li-Jun; Hu, Rong; Lujan, Brendan; Chen, Juan; Zhang, Jian-Jian; Nakano, Yasuko; Cui, Tian-Yuan; Liao, Ming-Xia; Chen, Jin-Cao; Man, Heng-Ye; Feng, Hua; Wan, Qi

    2016-01-01

    NMDA receptors are Ca2+-permeable ion channels. The activation of NMDA receptors requires agonist glutamate and co-agonist glycine. Recent evidence indicates that NMDA receptor also has metabotropic function. Here we report that in cultured mouse hippocampal neurons, glycine increases AMPA receptor-mediated currents independent of the channel activity of NMDA receptors and the activation of glycine receptors. The potentiation of AMPA receptor function by glycine is antagonized by the inhibition of ERK1/2. In the hippocampal neurons and in the HEK293 cells transfected with different combinations of NMDA receptors, glycine preferentially acts on GluN2A-containing NMDA receptors (GluN2ARs), but not GluN2B-containing NMDA receptors (GluN2BRs), to enhance ERK1/2 phosphorylation independent of the channel activity of GluN2ARs. Without requiring the channel activity of GluN2ARs, glycine increases AMPA receptor-mediated currents through GluN2ARs. Thus, these results reveal a metabotropic function of GluN2ARs in mediating glycine-induced potentiation of AMPA receptor function via ERK1/2 activation.

  16. Cellular trafficking of nicotinic acetylcholine receptors

    Institute of Scientific and Technical Information of China (English)

    Paul A ST JOHN

    2009-01-01

    Nicotinic acetylcholine receptors (nAChRs) play critical roles throughout the body. Precise regulation of the cellular location and availability of nAChRs on neurons and target cells is critical to their proper function. Dynamic, post-translational regulation of nAChRs, particularly control of their movements among the different compartments of cells, is an important aspect of that regulation. A combination of new information and new techniques has the study of nAChR trafficking poised for new breakthroughs.

  17. Removal of Synaptic Ca2+-Permeable AMPA Receptors during Sleep.

    OpenAIRE

    Ulrich, Daniel; ROWAN, MICHAEL

    2011-01-01

    PUBLISHED here is accumulating evidence that sleep contributes to memory formation and learning, but the underlying cellular mechanisms are incompletely understood. To investigate the impact of sleep on excitatory synaptic transmission, we obtained whole-cell patch-clamp recordings from layer V pyramidal neurons in acute slices of somatosensory cortex of juvenile rats (postnatal days 21-25). In animals after the dark period, philanthotoxin 74 (PhTx)-sensitive calcium-permeable AMPA recepto...

  18. C-terminal interactors of the AMPA receptor auxiliary subunit Shisa9.

    Directory of Open Access Journals (Sweden)

    Anna R Karataeva

    Full Text Available Shisa9 (initially named CKAMP44 has been identified as auxiliary subunit of the AMPA-type glutamate receptors and was shown to modulate its physiological properties. Shisa9 is a type-I transmembrane protein and contains a C-terminal PDZ domain that potentially interacts with cytosolic proteins. In this study, we performed a yeast two-hybrid screening that yielded eight PDZ domain-containing interactors of Shisa9, which were independently validated. The identified interactors are known scaffolding proteins residing in the neuronal postsynaptic density. To test whether C-terminal scaffolding interactions of Shisa9 affect synaptic AMPA receptor function in the hippocampus, we disrupted these interactions using a Shisa9 C-terminal mimetic peptide. In the absence of scaffolding interactions of Shisa9, glutamatergic AMPA receptor-mediated synaptic currents in the lateral perforant path of the mouse hippocampus had a faster decay time, and paired-pulse facilitation was reduced. Furthermore, disruption of the PDZ interactions between Shisa9 and its binding partners affected hippocampal network activity. Taken together, our data identifies novel interaction partners of Shisa9, and shows that the C-terminal interactions of Shisa9 through its PDZ domain interaction motif are important for AMPA receptor synaptic and network functions.

  19. 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

    A series of racemic aryl-substituted phenylalanines was synthesized and evaluated in vitro at recombinant rat GluA1−3, at GluK1−3, and at native AMPA receptors. The individual enantiomers of two target compounds, (RS)-2-amino-3-(3,4-dichloro-5-(5-hydroxypyridin-3-yl)phenyl)- propanoic acid (37...

  20. 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

    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 trea...

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

    International Nuclear Information System (INIS)

    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 [3H]MK801, [3H]AMPA and [3H]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. [3H]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 [3H]MK801 binding was observed in layers II-III in the schizophrenia group. No statistically significant differences were observed for [3H] kainate binding between the two groups. These results suggest that ionotropic glutamate receptors are differentially altered in the ACC of schizophrenia. The increase in [3H]AMPA and [3H]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

  3. 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

  4. Signalling mechanism for somatostatin receptor 5-mediated suppression of AMPA responses in rat retinal ganglion cells.

    Science.gov (United States)

    Deng, Qin-Qin; Sheng, Wen-Long; Zhang, Gong; Weng, Shi-Jun; Yang, Xiong-Li; Zhong, Yong-Mei

    2016-08-01

    Somatostatin (SRIF) is involved in a variety of physiological functions via the activation of five subtypes of specific receptors (sst1-5). Here, we investigated the effects of SRIF on AMPA receptor (AMPAR)-mediated currents (AMPA currents) in isolated rat retinal ganglion cells (GCs) using patch-clamp techniques. Immunofluorescence double labelling demonstrated the expression of sst5 in rat GCs. Consistent to this, whole cell AMPA currents of GCs were dose-dependently suppressed by SRIF, and the effect was reversed by the sst5 antagonist BIM-23056. Intracellular dialysis of GDP-β-S or pre-incubation with the Gi/o inhibitor pertussis toxin (PTX) abolished the SRIF effect. The SRIF effect was mimicked by the administration of either 8-Br-cAMP or forskolin, but was eliminated by the protein kinase A (PKA) antagonists H-89/KT5720/Rp-cAMP. Moreover, SRIF increased intracellular Ca(2+) levels and did not suppress the AMPA currents when GCs were infused with an intracellular Ca(2+)-free solution or in the presence of ryanodine receptor modulators caffeine/ryanodine. Furthermore, the SRIF effect was eliminated when the activity of calmodulin (CaM), calcineurin and protein phosphatase 1 (PP1) was blocked with W-7, FK-506 and okadaic acid, respectively. SRIF persisted to suppress the AMPA currents when cGMP-protein kinase G (PKG) and phosphatidylinositol (PI)-/phosphatidylcholine (PC)-phospholipase C (PLC) signalling pathways were blocked. In rat flat-mount retinas, SRIF suppressed AMPAR-mediated light-evoked excitatory postsynaptic currents (L-EPSCs) in GCs. We conclude that a distinct Gi/o/cAMP-PKA/ryanodine/Ca(2+)/CaM/calcineurin/PP1 signalling pathway comes into play due to the activation of sst5 to mediate the SRIF effect on GCs. PMID:26969240

  5. Synergy of AMPA and NMDA Receptor Currents in Dopaminergic Neurons: A Modeling Study.

    Science.gov (United States)

    Zakharov, Denis; Lapish, Christopher; Gutkin, Boris; Kuznetsov, Alexey

    2016-01-01

    Dopaminergic (DA) neurons display two modes of firing: low-frequency tonic and high-frequency bursts. The high frequency firing within the bursts is attributed to NMDA, but not AMPA receptor activation. In our models of the DA neuron, both biophysical and abstract, the NMDA receptor current can significantly increase their firing frequency, whereas the AMPA receptor current is not able to evoke high-frequency activity and usually suppresses firing. However, both currents are produced by glutamate receptors and, consequently, are often co-activated. Here we consider combined influence of AMPA and NMDA synaptic input in the models of the DA neuron. Different types of neuronal activity (resting state, low frequency, or high frequency firing) are observed depending on the conductance of the AMPAR and NMDAR currents. In two models, biophysical and reduced, we show that the firing frequency increases more effectively if both receptors are co-activated for certain parameter values. In particular, in the more quantitative biophysical model, the maximal frequency is 40% greater than that with NMDAR alone. The dynamical mechanism of such frequency growth is explained in the framework of phase space evolution using the reduced model. In short, both the AMPAR and NMDAR currents flatten the voltage nullcline, providing the frequency increase, whereas only NMDA prevents complete unfolding of the nullcline, providing robust firing. Thus, we confirm a major role of the NMDAR in generating high-frequency firing and conclude that AMPAR activation further significantly increases the frequency. PMID:27252643

  6. 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.

  7. Bi-directional modulation of AMPA receptor unitary conductance by synaptic activity

    Directory of Open Access Journals (Sweden)

    Matthews Paul

    2004-11-01

    Full Text Available Abstract Background Knowledge of how synapses alter their efficiency of communication is central to the understanding of learning and memory. The most extensively studied forms of synaptic plasticity are long-term potentiation (LTP and its counterpart long-term depression (LTD of AMPA receptor-mediated synaptic transmission. In the CA1 region of the hippocampus, it has been shown that LTP often involves a rapid increase in the unitary conductance of AMPA receptor channels. However, LTP can also occur in the absence of any alteration in AMPA receptor unitary conductance. In the present study we have used whole-cell dendritic recording, failures analysis and non-stationary fluctuation analysis to investigate the mechanism of depotentiation of LTP. Results We find that when LTP involves an increase in unitary conductance, subsequent depotentiation invariably involves the return of unitary conductance to pre-LTP values. In contrast, when LTP does not involve a change in unitary conductance then depotentiation also occurs in the absence of any change in unitary conductance, indicating a reduction in the number of activated receptors as the most likely mechanism. Conclusions These data show that unitary conductance can be bi-directionally modified by synaptic activity. Furthermore, there are at least two distinct mechanisms to restore synaptic strength from a potentiated state, which depend upon the mechanism of the previous potentiation.

  8. Effects of intrathecal NMDA and AMPA receptors agonists or antagonists on antinociception of propofol

    Institute of Scientific and Technical Information of China (English)

    Ai-junXU; Shi-mingDUAN; Yin-mingZENG

    2004-01-01

    AIM: To study the effects of intrathecal (it) agonists and antagonists of N-methyl-D-aspartate (NMDA) and alphaamino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors and NMDAR1 antisense oligodeoxynucleotides (AS ODN) on the antinociception of propofol. METHODS: Hot-plate test (HPPT) and acetic acid-induced writhing test were used to measure the nociceptive thresholds in mice. The effects of intrathecal NMDA, AMPA, MK-801, NBQX, or NMDAR1 AS ODN on the antinociception of propofol were observed.RESULTS: Propofol (25, 50 mg/kg, ip) displayed an appreciable antinociceptive effect in hot-plate test and acetic acid-induced writhing test. NMDA (12.5, 25 ng, it) or AMPA (1.25, 2.5 ng, it) exhibited no effects on the behavior but decreased HPPT significantly compared with basal HPPT and aCSF group (P<0.05, P<0.01). No effects on behavior and HPPT were obtained in NMDA (6.25 ng, it) or AMPA (0.625 ng, it) groups. NMDA (6.25, 12.5, and 25 ng, it) dose-dependently decreased the HPPT in propofol-treated group. AMPA (1.25, 2.5 ng, it) also decreased HPPT significantly. MK-801 (0.25, 0.5 μg, it) or NBQX (0.25, 0.5 μg, it) groups had no behavioral changes, two antagonists 0.5 μg but not 0.25 μg increased HPPT in conscious or propofol-treated mice. AS ODN (5, 10, and 20 μg, it) groups exhibited dose-dependent increased in HPPT in propofol-treated groups compared with aCSF group(P<0.05, P<0.01). CONCLUSION: Both agonists NMDA and AMPA reversed the antinociception of propofol.MK-801, NBQX, and NMDAR1 AS ODN potentiated the antinociceptive effects of propofol. Propofol produced antinociception through an interaction with spinal NMDA and AMPA receptors in mice.

  9. Intracellular Ca2+ release through ryanodine receptors contributes to AMPA receptor-mediated mitochondrial dysfunction and ER stress in oligodendrocytes

    Science.gov (United States)

    Ruiz, A; Matute, C; Alberdi, E

    2010-01-01

    Overactivation of ionotropic glutamate receptors in oligodendrocytes induces cytosolic Ca2+ overload and excitotoxic death, a process that contributes to demyelination and multiple sclerosis. Excitotoxic insults cause well-characterized mitochondrial alterations and endoplasmic reticulum (ER) dysfunction, which is not fully understood. In this study, we analyzed the contribution of ER-Ca2+ release through ryanodine receptors (RyRs) and inositol triphosphate receptors (IP3Rs) to excitotoxicity in oligodendrocytes in vitro. First, we observed that oligodendrocytes express all previously characterized RyRs and IP3Rs. Blockade of Ca2+-induced Ca2+ release by TMB-8 following α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor-mediated insults attenuated both oligodendrocyte death and cytosolic Ca2+ overload. In turn, RyR inhibition by ryanodine reduced as well the Ca2+ overload whereas IP3R inhibition was ineffective. Furthermore, AMPA-triggered mitochondrial membrane depolarization, oxidative stress and activation of caspase-3, which in all instances was diminished by RyR inhibition. In addition, we observed that AMPA induced an ER stress response as revealed by α subunit of the eukaryotic initiation factor 2α phosphorylation, overexpression of GRP chaperones and RyR-dependent cleavage of caspase-12. Finally, attenuating ER stress with salubrinal protected oligodendrocytes from AMPA excitotoxicity. Together, these results show that Ca2+ release through RyRs contributes to cytosolic Ca2+ overload, mitochondrial dysfunction, ER stress and cell death following AMPA receptor-mediated excitotoxicity in oligodendrocytes. PMID:21364659

  10. Role of TARP interaction in S-SCAM-mediated regulation of AMPA receptors

    OpenAIRE

    Danielson, Eric; Metallo, Jacob; Lee, Sang H.

    2012-01-01

    Scaffolding proteins are involved in the incorporation, anchoring, maintenance, and removal of AMPA receptors (AMPARs) at synapses, either through a direct interaction with AMPARs or via indirect association through auxiliary subunits of transmembrane AMPAR regulatory proteins (TARPs). Synaptic scaffolding molecule (S-SCAM) is a newly characterized member of the scaffolding proteins critical for the regulation and maintenance of AMPAR levels at synapses, and directly binds to TARPs through a ...

  11. UEV-1 is an ubiquitin-conjugating enzyme variant that regulates glutamate receptor trafficking in C. elegans neurons.

    Directory of Open Access Journals (Sweden)

    Lawrence B Kramer

    Full Text Available The regulation of AMPA-type glutamate receptor (AMPAR membrane trafficking is a key mechanism by which neurons regulate synaptic strength and plasticity. AMPAR trafficking is modulated through a combination of receptor phosphorylation, ubiquitination, endocytosis, and recycling, yet the factors that mediate these processes are just beginning to be uncovered. Here we identify the ubiquitin-conjugating enzyme variant UEV-1 as a regulator of AMPAR trafficking in vivo. We identified mutations in uev-1 in a genetic screen for mutants with altered trafficking of the AMPAR subunit GLR-1 in C. elegans interneurons. Loss of uev-1 activity results in the accumulation of GLR-1 in elongated accretions in neuron cell bodies and along the ventral cord neurites. Mutants also have a corresponding behavioral defect--a decrease in spontaneous reversals in locomotion--consistent with diminished GLR-1 function. The localization of other synaptic proteins in uev-1-mutant interneurons appears normal, indicating that the GLR-1 trafficking defects are not due to gross deficiencies in synapse formation or overall protein trafficking. We provide evidence that GLR-1 accumulates at RAB-10-containing endosomes in uev-1 mutants, and that receptors arrive at these endosomes independent of clathrin-mediated endocytosis. UEV-1 homologs in other species bind to the ubiquitin-conjugating enzyme Ubc13 to create K63-linked polyubiquitin chains on substrate proteins. We find that whereas UEV-1 can interact with C. elegans UBC-13, global levels of K63-linked ubiquitination throughout nematodes appear to be unaffected in uev-1 mutants, even though UEV-1 is broadly expressed in most tissues. Nevertheless, ubc-13 mutants are similar in phenotype to uev-1 mutants, suggesting that the two proteins do work together to regulate GLR-1 trafficking. Our results suggest that UEV-1 could regulate a small subset of K63-linked ubiquitination events in nematodes, at least one of which is critical

  12. 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. PMID:27061850

  13. Functional characterization of Tet-AMPA [tetrazolyl-2-amino-3-(3-hydroxy-5-methyl- 4-isoxazolyl)propionic acid] analogues at ionotropic glutamate receptors GluR1-GluR4. The molecular basis for the functional selectivity profile of 2-Bn-Tet-AMPA

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Christesen, Thomas; Bølcho, Ulrik;

    2007-01-01

    Four 2-substituted Tet-AMPA [Tet = tetrazolyl, AMPA = 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid] analogues were characterized functionally at the homomeric AMPA receptors GluR1i, GluR2Qi, GluR3i, and GluR4i in a Fluo-4/Ca2+ assay. Whereas 2-Et-Tet-AMPA, 2-Pr-Tet-AMPA, and 2-iPr...

  14. Competitive antagonism of AMPA receptors by ligands of different classes

    DEFF Research Database (Denmark)

    Hogner, Anders; Greenwood, Jeremy R; Liljefors, Tommy;

    2003-01-01

    Ionotropic glutamate receptors (iGluRs) constitute a family of ligand-gated ion channels that are essential for mediating fast synaptic transmission in the central nervous system. This study presents a high-resolution X-ray structure of the competitive antagonist (S)-2-amino-3-[5-tert-butyl-3-(ph...

  15. Going Mobile: AMPA Receptors Move Synapse to Synapse In Vivo

    OpenAIRE

    Rongo, Christopher

    2013-01-01

    Plasticity models invoke the synaptic delivery of AMPARs, yet we know little about how receptors move in vivo. In this issue of Neuron, Hoerndli et al. show that lateral diffusion and kinesin-mediated transport move AMPARs between synapses in vivo.

  16. The AMPA receptor subunit GluR1 regulates dendritic architecture of motor neurons

    Science.gov (United States)

    Inglis, Fiona M.; Crockett, Richard; Korada, Sailaja; Abraham, Wickliffe C.; Hollmann, Michael; Kalb, Robert G.

    2002-01-01

    The morphology of the mature motor neuron dendritic arbor is determined by activity-dependent processes occurring during a critical period in early postnatal life. The abundance of the AMPA receptor subunit GluR1 in motor neurons is very high during this period and subsequently falls to a negligible level. To test the role of GluR1 in dendrite morphogenesis, we reintroduced GluR1 into rat motor neurons at the end of the critical period and quantitatively studied the effects on dendrite architecture. Two versions of GluR1 were studied that differed by the amino acid in the "Q/R" editing site. The amino acid occupying this site determines single-channel conductance, ionic permeability, and other essential electrophysiologic properties of the resulting receptor channels. We found large-scale remodeling of dendritic architectures in a manner depending on the amino acid occupying the Q/R editing site. Alterations in the distribution of dendritic arbor were not prevented by blocking NMDA receptors. These observations suggest that the expression of GluR1 in motor neurons modulates a component of the molecular substrate of activity-dependent dendrite morphogenesis. The control of these events relies on subunit-specific properties of AMPA receptors.

  17. (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

    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...... 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...... 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)....

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

    Science.gov (United States)

    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…

  19. AMPA and GABA receptor antagonists and their interaction in rats with a genetic form of absence epilepsy

    NARCIS (Netherlands)

    Kaminski, R.M.; Rijn, C.M. van; Turski, W.A.; Czuczwar, S.J.; Luijtelaar, E.L.J.M. van

    2001-01-01

    The effects of combined and single administration of the -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist, 7,8-methylenedioxy-1-(4-aminophenyl)-4-methyl-3-acetyl-4,5-dihydro-2,3 -benzodiazepine (LY 300164), and of the GABAB receptor antagonist -aminopropyl-n-butyl-phosp

  20. Structural basis for AMPA receptor activation and ligand selectivity

    DEFF Research Database (Denmark)

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

    2002-01-01

    and binding experiments, has been used to increase our knowledge concerning the ionotropic glutamate receptor GluR2 at the molecular level. Five high-resolution X-ray structures of the ligand-binding domain of GluR2 (S1S2J) complexed with the three agonists (S)-2-amino-3-[3-hydroxy-5-(2-methyl-2H-tetrazol-5...

  1. Estrous Cycle-Dependent Phasic Changes in the Stoichiometry of Hippocampal Synaptic AMPA Receptors in Rats

    OpenAIRE

    Hirobumi Tada; Mayu Koide; Wakana Ara; Yusuke Shibata; Toshiya Funabashi; Kumiko Suyama; Takahisa Goto; Takuya Takahashi

    2015-01-01

    Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA) task (hippocampus-dependent contextual fear-learning task) drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to dri...

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

    Directory of Open Access Journals (Sweden)

    Shira Knafo

    2012-02-01

    Full Text Available Cell adhesion molecules and downstream growth factor-dependent signaling are critical for brain development and synaptic plasticity, and they have been linked to cognitive function in adult animals. We have previously developed a mimetic peptide (FGL from the neural cell adhesion molecule (NCAM 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 in hippocampal CA1 neurons. This effect is mediated by a facilitated synaptic delivery of AMPA receptors, which is accompanied by enhanced NMDA receptor-dependent long-term potentiation (LTP. Both LTP and cognitive enhancement are mediated by an initial PKC activation, which is followed by persistent CaMKII 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.

  3. 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…

  4. Interfering with interferon receptor sorting and trafficking: impact on signaling.

    Science.gov (United States)

    Claudinon, Julie; Monier, Marie-Noëlle; Lamaze, Christophe

    2007-01-01

    Interferons (IFNs) and their receptors (IFN-Rs) play fundamental roles in a multitude of biological functions. Many articles and reviews emphasize that the JAK/STAT machinery is obligatory for relay of the information transmitted by IFNs after binding to their cognate receptors at the plasma membrane. In contrast, very few studies have addressed the endocytosis and the intracellular trafficking of IFN-Rs, the immediate step following IFN binding. However, recent findings have shed light on the importance of IFN-R sorting and trafficking in the control of IFN signaling. Thus, IFN-Rs can be included in the growing family of signaling receptors for which regulation of biological activity critically involves endocytosis and trafficking. PMID:17493737

  5. 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

    2012-09-01

    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.

  6. Auxiliary Subunit GSG1L Acts to Suppress Calcium-Permeable AMPA Receptor Function

    Science.gov (United States)

    McGee, Thomas P.; Bats, Cécile

    2015-01-01

    AMPA-type glutamate receptors are ligand-gated cation channels responsible for a majority of the fast excitatory synaptic transmission in the brain. Their behavior and calcium permeability depends critically on their subunit composition and the identity of associated auxiliary proteins. Calcium-permeable AMPA receptors (CP-AMPARs) contribute to various forms of synaptic plasticity, and their dysfunction underlies a number of serious neurological conditions. For CP-AMPARs, the prototypical transmembrane AMPAR regulatory protein stargazin, which acts as an auxiliary subunit, enhances receptor function by increasing single-channel conductance, slowing channel gating, increasing calcium permeability, and relieving the voltage-dependent block by endogenous intracellular polyamines. We find that, in contrast, GSG1L, a transmembrane auxiliary protein identified recently as being part of the AMPAR proteome, acts to reduce the weighted mean single-channel conductance and calcium permeability of recombinant CP-AMPARs, while increasing polyamine-dependent rectification. To examine the effects of GSG1L on native AMPARs, we manipulated its expression in cerebellar and hippocampal neurons. Transfection of GSG1L into mouse cultured cerebellar stellate cells that lack this protein increased the inward rectification of mEPSCs. Conversely, shRNA-mediated knockdown of endogenous GSG1L in rat cultured hippocampal pyramidal neurons led to an increase in mEPSC amplitude and in the underlying weighted mean single-channel conductance, revealing that GSG1L acts to suppress current flow through native CP-AMPARs. Thus, our data suggest that GSG1L extends the functional repertoire of AMPAR auxiliary subunits, which can act not only to enhance but also diminish current flow through their associated AMPARs. SIGNIFICANCE STATEMENT Calcium-permeable AMPA receptors (CP-AMPARs) are an important group of receptors for the neurotransmitter glutamate. These receptors contribute to various forms of

  7. Estrous Cycle-Dependent Phasic Changes in the Stoichiometry of Hippocampal Synaptic AMPA Receptors in Rats.

    Directory of Open Access Journals (Sweden)

    Hirobumi Tada

    Full Text Available Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA task (hippocampus-dependent contextual fear-learning task drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to drive CP-AMPARs into the CA3-CA1 synapses of ovariectomized rats only when estrogen was present. Thus, changes in the stoichiometry of AMPA receptors during learning depend on estrogen levels. Furthermore, the induction of long-term potentiation (LTP after IA task was prevented during the proestrous period, while intact LTP is still expressed after IA task during other period of the estrous cycle. Consistent with this finding, rats conditioned by IA training failed to acquire hippocampus-dependent Y-maze task during the proestrous period. On the other hand, during other estrous period, rats were able to learn Y-maze task after IA conditioning. These results suggest that high estrogen levels prevent the IA learning-induced delivery of CP-AMPARs into hippocampal CA3-CA1 synapses and limit synaptic plasticity after IA task, thus preventing the acquisition of additional learning.

  8. Estrous Cycle-Dependent Phasic Changes in the Stoichiometry of Hippocampal Synaptic AMPA Receptors in Rats.

    Science.gov (United States)

    Tada, Hirobumi; Koide, Mayu; Ara, Wakana; Shibata, Yusuke; Funabashi, Toshiya; Suyama, Kumiko; Goto, Takahisa; Takahashi, Takuya

    2015-01-01

    Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA) task (hippocampus-dependent contextual fear-learning task) drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to drive CP-AMPARs into the CA3-CA1 synapses of ovariectomized rats only when estrogen was present. Thus, changes in the stoichiometry of AMPA receptors during learning depend on estrogen levels. Furthermore, the induction of long-term potentiation (LTP) after IA task was prevented during the proestrous period, while intact LTP is still expressed after IA task during other period of the estrous cycle. Consistent with this finding, rats conditioned by IA training failed to acquire hippocampus-dependent Y-maze task during the proestrous period. On the other hand, during other estrous period, rats were able to learn Y-maze task after IA conditioning. These results suggest that high estrogen levels prevent the IA learning-induced delivery of CP-AMPARs into hippocampal CA3-CA1 synapses and limit synaptic plasticity after IA task, thus preventing the acquisition of additional learning. PMID:26121335

  9. Effects of 2,3-benzodiazepine AMPA receptor antagonists on dopamine turnover in the striatum of rats with experimental parkinsonism.

    Science.gov (United States)

    Megyeri, Katalin; Marko, Bernadett; Sziray, Nora; Gacsalyi, Istvan; Juranyi, Zsolt; Levay, Gyorgy; Harsing, Laszlo G

    2007-03-15

    Although levodopa is the current "gold standard" for treatment of Parkinson's disease, there has been disputation on whether AMPA receptor antagonists can be used as adjuvant therapy to improve the effects of levodopa. Systemic administration of levodopa, the precursor of dopamine, increases brain dopamine turnover rate and this elevated turnover is believed to be essential for successful treatment of Parkinson's disease. However, long-term treatment of patients with levodopa often leads to development of dyskinesia. Therefore, drugs that feature potentiation of dopamine turnover rate and are able to reduce daily levodopa dosages might be used as adjuvant in the treatment of patients suffering from Parkinson's disease. To investigate such combined treatment, we have examined the effects of two non-competitive AMPA receptor antagonists, GYKI-52466 and GYKI-53405, alone or in combination with levodopa on dopamine turnover rate in 6-hydroxydopamine-lesioned striatum of the rat. We found here that repeated administration of levodopa, added with the peripheral DOPA decarboxylase inhibitor carbidopa, increased dopamine turnover rate after lesioning the striatum with 6-hydroxydopamine. Moreover, combination of levodopa with GYKI-52466 or GYKI-53405 further increased dopamine turnover enhanced by levodopa administration while the AMPA receptor antagonists by themselves failed to influence striatal dopamine turnover. We concluded from the present data that potentiation observed between levodopa and AMPA receptor antagonists may reflect levodopa-sparing effects in clinical treatment indicating the therapeutic potential of such combination in the management of Parkinson's disease.

  10. Membrane Trafficking of Death Receptors: Implications on Signalling

    Directory of Open Access Journals (Sweden)

    Wulf Schneider-Brachert

    2013-07-01

    Full Text Available Death receptors were initially recognised as potent inducers of apoptotic cell death and soon ambitious attempts were made to exploit selective ignition of controlled cellular suicide as therapeutic strategy in malignant diseases. However, the complexity of death receptor signalling has increased substantially during recent years. Beyond activation of the apoptotic cascade, involvement in a variety of cellular processes including inflammation, proliferation and immune response was recognised. Mechanistically, these findings raised the question how multipurpose receptors can ensure selective activation of a particular pathway. A growing body of evidence points to an elegant spatiotemporal regulation of composition and assembly of the receptor-associated signalling complex. Upon ligand binding, receptor recruitment in specialized membrane compartments, formation of receptor-ligand clusters and internalisation processes constitute key regulatory elements. In this review, we will summarise the current concepts of death receptor trafficking and its implications on receptor-associated signalling events.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Intracellular Ca2+ and not the extracellular matrix determines surface dynamics of AMPA-type glutamate receptors on aspiny neurons

    OpenAIRE

    Klueva, Julia; Gundelfinger, Eckart D; Frischknecht, R. Renato; Heine, Martin

    2014-01-01

    The perisynaptic extracellular matrix (ECM) contributes to the control of the lateral mobility of AMPA-type glutamate receptors (AMPARs) at spine synapses of principal hippocampal neurons. Here, we have studied the effect of the ECM on the lateral mobility of AMPARs at shaft synapses of aspiny interneurons. Single particle tracking experiments revealed that the removal of the hyaluronan-based ECM with hyaluronidase does not affect lateral receptor mobility on the timescale of seconds. Similar...

  13. 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...

  14. Reinforcement-related regulation of AMPA glutamate receptor subunits in the ventral tegmental area enhances motivation for cocaine.

    Science.gov (United States)

    Choi, Kwang Ho; Edwards, Scott; Graham, Danielle L; Larson, Erin B; Whisler, Kimberly N; Simmons, Diana; Friedman, Allyson K; Walsh, Jessica J; Rahman, Zia; Monteggia, Lisa M; Eisch, Amelia J; Neve, Rachael L; Nestler, Eric J; Han, Ming-Hu; Self, David W

    2011-05-25

    Chronic cocaine use produces numerous biological changes in brain, but relatively few are functionally associated with cocaine reinforcement. Here we show that daily intravenous cocaine self-administration, but not passive cocaine administration, induces dynamic upregulation of the AMPA glutamate receptor subunits GluR1 and GluR2 in the ventral tegmental area (VTA) of rats. Increases in GluR1 protein and GluR1(S845) phosphorylation are associated with increased GluR1 mRNA in self-administering animals, whereas increased GluR2 protein levels occurred despite substantial decreases in GluR2 mRNA. We investigated the functional significance of GluR1 upregulation in the VTA on cocaine self-administration using localized viral-mediated gene transfer. Overexpression of GluR1(WT) in rat VTA primarily infected dopamine neurons (75%) and increased AMPA receptor-mediated membrane rectification in these neurons with AMPA application. Similar GluR1(WT) overexpression potentiated locomotor responses to intra-VTA AMPA, but not NMDA, infusions. In cocaine self-administering animals, overexpression of GluR1(WT) in the VTA markedly increased the motivation for cocaine injections on a progressive ratio schedule of cocaine reinforcement. In contrast, overexpression of protein kinase A-resistant GluR1(S845A) in the VTA reduced peak rates of cocaine self-administration on a fixed ratio reinforcement schedule. Neither viral vector altered sucrose self-administration, and overexpression of GluR1(WT) or GluR1(S845A) in the adjacent substantia nigra had no effect on cocaine self-administration. Together, these results suggest that dynamic regulation of AMPA receptors in the VTA during cocaine self-administration contributes to cocaine addiction by acting to facilitate subsequent cocaine use.

  15. Episodic sucrose intake during food restriction increases synaptic abundance of AMPA receptors in nucleus accumbens and augments intake of sucrose following restoration of ad libitum feeding.

    Science.gov (United States)

    Peng, X-X; Lister, A; Rabinowitsch, A; Kolaric, R; Cabeza de Vaca, S; Ziff, E B; Carr, K D

    2015-06-01

    Weight-loss dieting often leads to loss of control, rebound weight gain, and is a risk factor for binge pathology. Based on findings that food restriction (FR) upregulates sucrose-induced trafficking of glutamatergic AMPA receptors to the nucleus accumbens (NAc) postsynaptic density (PSD), this study was an initial test of the hypothesis that episodic "breakthrough" intake of forbidden food during dieting interacts with upregulated mechanisms of synaptic plasticity to increase reward-driven feeding. Ad libitum (AL) fed and FR subjects consumed a limited amount of 10% sucrose, or had access to water, every other day for 10 occasions. Beginning three weeks after return of FR rats to AL feeding, when 24-h chow intake and rate of body weight gain had normalized, subjects with a history of sucrose intake during FR consumed more sucrose during a four week intermittent access protocol than the two AL groups and the group that had access to water during FR. In an experiment that substituted noncontingent administration of d-amphetamine for sucrose, FR subjects displayed an enhanced locomotor response during active FR but a blunted response, relative to AL subjects, during recovery from FR. This result suggests that the enduring increase in sucrose consumption is unlikely to be explained by residual enhancing effects of FR on dopamine signaling. In a biochemical experiment which paralleled the sucrose behavioral experiment, rats with a history of sucrose intake during FR displayed increased abundance of pSer845-GluA1, GluA2, and GluA3 in the NAc PSD relative to rats with a history of FR without sucrose access and rats that had been AL throughout, whether they had a history of episodic sucrose intake or not. A history of FR, with or without a history of sucrose intake, was associated with increased abundance of GluA1. A terminal 15-min bout of sucrose intake produced a further increase in pSer845-GluA1 and GluA2 in subjects with a history of sucrose intake during FR

  16. DCP-LA stimulates AMPA receptor exocytosis through CaMKII activation due to PP-1 inhibition.

    Science.gov (United States)

    Kanno, Takeshi; Yaguchi, Takahiro; Nagata, Tetsu; Tanaka, Akito; Nishizaki, Tomoyuki

    2009-10-01

    The linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) activated Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) by inhibiting protein phosphatase-1 (PP-1). DCP-LA induced a transient huge facilitation of synaptic transmission monitored from the CA1 region of rat hippocampal slices, which was largely inhibited by the CaMKII inhibitor KN-93. DCP-LA potentiated kainate-evoked whole-cell membrane currents for Xenopus oocytes expressing alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors composed of the GluR1, GluR3, GluR1/GluR2, GluR1/GluR3, and GluR1/GluR2/GluR3 subunits, and the potentiation was significantly inhibited by KN-93. A similar potentiation was still found with mutant GluR1 (S831A) receptor lacking CaMKII phosphorylation site. The GluR1 and GluR2 subunits formed AMPA receptors in the rat hippocampus, and DCP-LA increased expression of both the subunits on the plasma membrane. The DCP-LA action was blocked by KN-93 and the exocytosis inhibitor botulinum toxin type A, but not by the endocytosis inhibitor phenylarsine oxide. DCP-LA, thus, appears to activate CaMKII through PP-1 inhibition, that stimulates AMPA receptor exocytosis to increase expression of the receptors on the plasma membrane, responsible for potentiate AMPA receptor responses and facilitation of hippocampal synaptic transmission. PMID:19492412

  17. DCP-LA stimulates AMPA receptor exocytosis through CaMKII activation due to PP-1 inhibition.

    Science.gov (United States)

    Kanno, Takeshi; Yaguchi, Takahiro; Nagata, Tetsu; Tanaka, Akito; Nishizaki, Tomoyuki

    2009-10-01

    The linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) activated Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) by inhibiting protein phosphatase-1 (PP-1). DCP-LA induced a transient huge facilitation of synaptic transmission monitored from the CA1 region of rat hippocampal slices, which was largely inhibited by the CaMKII inhibitor KN-93. DCP-LA potentiated kainate-evoked whole-cell membrane currents for Xenopus oocytes expressing alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors composed of the GluR1, GluR3, GluR1/GluR2, GluR1/GluR3, and GluR1/GluR2/GluR3 subunits, and the potentiation was significantly inhibited by KN-93. A similar potentiation was still found with mutant GluR1 (S831A) receptor lacking CaMKII phosphorylation site. The GluR1 and GluR2 subunits formed AMPA receptors in the rat hippocampus, and DCP-LA increased expression of both the subunits on the plasma membrane. The DCP-LA action was blocked by KN-93 and the exocytosis inhibitor botulinum toxin type A, but not by the endocytosis inhibitor phenylarsine oxide. DCP-LA, thus, appears to activate CaMKII through PP-1 inhibition, that stimulates AMPA receptor exocytosis to increase expression of the receptors on the plasma membrane, responsible for potentiate AMPA receptor responses and facilitation of hippocampal synaptic transmission.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. A novel dualistic profile of an allosteric AMPA receptor modulator identified through studies on recombinant receptors, mouse hippocampal synapses and crystal structures

    DEFF Research Database (Denmark)

    Christiansen, G B; Harbak, Barbara; Hede, S E;

    2015-01-01

    Positive allosteric modulators (PAMs) of 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptors receive increasing interest as therapeutic drugs and have long served as important experimental tools in the study of the molecular mechanisms underlying glutamate-mediated neurotra...

  20. AMPA and NMDA glutamate receptors are found in both peptidergic and non-peptidergic primary afferent neurons in the rat

    OpenAIRE

    Willcockson, Helen; Valtschanoff, Juli

    2008-01-01

    Two distinct classes of nociceptive primary afferents, peptidergic and non-peptidergic, respond similarly to acute noxious stimulation; however the peptidergic afferents are more likely to play a role in inflammatory pain, while the non-peptidergic afferents may be more characteristically involved in neuropathic pain. Using multiple immunofluorescence, we determined the proportions of neurons in the rat L4 dorsal root ganglion (DRG) that co-express AMPA or NMDA glutamate receptors and markers...

  1. Calcyon is Necessary for Activity Dependent AMPA Receptor Internalization and LTD in CA1 Neurons of Hippocampus

    OpenAIRE

    Davidson, Heather Trantham; Xiao, Jiping; Dai, Rujuan; Bergson, Clare

    2009-01-01

    Calcyon is a single transmembrane endocytic protein that regulates clathrin assembly and clathrin mediated endocytosis in brain. Ultrastructural studies indicate that calcyon localizes to spines, but whether it regulates glutamate neurotransmission is not known. Here, we show that deletion of the calcyon gene in mice inhibits agonist stimulated endocytosis of AMPA receptors, without altering basal surface levels of the GluR1 or GluR2 subunits. Whole cell patch clamp studies of hippocampal neu...

  2. S-SCAM/MAGI-2 is an essential synaptic scaffolding molecule for the GluA2-containing maintenance pool of AMPA receptors.

    Science.gov (United States)

    Danielson, Eric; Zhang, Nanyan; Metallo, Jacob; Kaleka, Kanwardeep; Shin, Seung Min; Gerges, Nashaat; Lee, Sang H

    2012-05-16

    Synaptic plasticity, the cellular basis of learning and memory, involves the dynamic trafficking of AMPA receptors (AMPARs) into and out of synapses. One of the remaining key unanswered aspects of AMPAR trafficking is the mechanism by which synaptic strength is preserved despite protein turnover. In particular, the identity of AMPAR scaffolding molecule(s) involved in the maintenance of GluA2-containing AMPARs is completely unknown. Here we report that the synaptic scaffolding molecule (S-SCAM; also called membrane-associated guanylate kinase inverted-2 and atrophin interacting protein-1) plays the critical role of maintaining synaptic strength. Increasing S-SCAM levels in rat hippocampal neurons led to specific increases in the surface AMPAR levels, enhanced AMPAR-mediated synaptic transmission, and enlargement of dendritic spines, without significantly effecting GluN levels or NMDA receptor (NMDAR) EPSC. Conversely, decreasing S-SCAM levels by RNA interference-mediated knockdown caused the loss of synaptic AMPARs, which was followed by a severe reduction in the dendritic spine density. Importantly, S-SCAM regulated synaptic AMPAR levels in a manner, dependent on GluA2 not GluA1, sensitive to N-ethylmaleimide-sensitive fusion protein interaction, and independent of activity. Further, S-SCAM increased surface AMPAR levels in the absence of PSD-95, while PSD-95 was dependent on S-SCAM to increase surface AMPAR levels. Finally, S-SCAM overexpression hampered NMDA-induced internalization of AMPARs and prevented the induction of long term-depression, while S-SCAM knockdown did not. Together, these results suggest that S-SCAM is an essential AMPAR scaffolding molecule for the GluA2-containing pool of AMPARs, which are involved in the constitutive pathway of maintaining synaptic strength. PMID:22593065

  3. A Computational Model for the AMPA Receptor Phosphorylation Master Switch Regulating Cerebellar Long-Term Depression.

    Science.gov (United States)

    Gallimore, Andrew R; Aricescu, A Radu; Yuzaki, Michisuke; Calinescu, Radu

    2016-01-01

    The expression of long-term depression (LTD) in cerebellar Purkinje cells results from the internalisation of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs) from the postsynaptic membrane. This process is regulated by a complex signalling pathway involving sustained protein kinase C (PKC) activation, inhibition of serine/threonine phosphatase, and an active protein tyrosine phosphatase, PTPMEG. In addition, two AMPAR-interacting proteins-glutamate receptor-interacting protein (GRIP) and protein interacting with C kinase 1 (PICK1)-regulate the availability of AMPARs for trafficking between the postsynaptic membrane and the endosome. Here we present a new computational model of these overlapping signalling pathways. The model reveals how PTPMEG cooperates with PKC to drive LTD expression by facilitating the effect of PKC on the dissociation of AMPARs from GRIP and thus their availability for trafficking. Model simulations show that LTD expression is increased by serine/threonine phosphatase inhibition, and negatively regulated by Src-family tyrosine kinase activity, which restricts the dissociation of AMPARs from GRIP under basal conditions. We use the model to expose the dynamic balance between AMPAR internalisation and reinsertion, and the phosphorylation switch responsible for the perturbation of this balance and for the rapid plasticity initiation and regulation. Our model advances the understanding of PF-PC LTD regulation and induction, and provides a validated extensible platform for more detailed studies of this fundamental synaptic process. PMID:26807999

  4. A Computational Model for the AMPA Receptor Phosphorylation Master Switch Regulating Cerebellar Long-Term Depression.

    Directory of Open Access Journals (Sweden)

    Andrew R Gallimore

    2016-01-01

    Full Text Available The expression of long-term depression (LTD in cerebellar Purkinje cells results from the internalisation of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPARs from the postsynaptic membrane. This process is regulated by a complex signalling pathway involving sustained protein kinase C (PKC activation, inhibition of serine/threonine phosphatase, and an active protein tyrosine phosphatase, PTPMEG. In addition, two AMPAR-interacting proteins-glutamate receptor-interacting protein (GRIP and protein interacting with C kinase 1 (PICK1-regulate the availability of AMPARs for trafficking between the postsynaptic membrane and the endosome. Here we present a new computational model of these overlapping signalling pathways. The model reveals how PTPMEG cooperates with PKC to drive LTD expression by facilitating the effect of PKC on the dissociation of AMPARs from GRIP and thus their availability for trafficking. Model simulations show that LTD expression is increased by serine/threonine phosphatase inhibition, and negatively regulated by Src-family tyrosine kinase activity, which restricts the dissociation of AMPARs from GRIP under basal conditions. We use the model to expose the dynamic balance between AMPAR internalisation and reinsertion, and the phosphorylation switch responsible for the perturbation of this balance and for the rapid plasticity initiation and regulation. Our model advances the understanding of PF-PC LTD regulation and induction, and provides a validated extensible platform for more detailed studies of this fundamental synaptic process.

  5. Rab8 modulates metabotropic glutamate receptor subtype 1 intracellular trafficking and signaling in a protein kinase C-dependent manner.

    Science.gov (United States)

    Esseltine, Jessica L; Ribeiro, Fabiola M; Ferguson, Stephen S G

    2012-11-21

    Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors (GPCRs) that are activated by glutamate, the primary excitatory neurotransmitter in the CNS. Alterations in glutamate receptor signaling are implicated in neuropathologies such as Alzheimer's disease, ischemia, and Huntington's disease among others. Group 1 mGluRs (mGluR1 and mGluR5) are primarily coupled to Gα(q/11) leading to the activation of phospholipase C and the formation of diacylglycerol and inositol 1,4,5-trisphosphate, which results in the release of intracellular calcium stores and protein kinase C (PKC) activation. Desensitization, endocytosis, and recycling are major mechanisms of GPCR regulation, and the intracellular trafficking of GPCRs is linked to the Rab family of small G proteins. Rab8 is a small GTPase that is specifically involved in the regulation of secretory/recycling vesicles, modulation of the actin cytoskeleton, and cell polarity. Rab8 has been shown to regulate the synaptic delivery of AMPA receptors during long-term potentiation and during constitutive receptor recycling. We show here that Rab8 interacts with the C-terminal tail of mGluR1a in an agonist-dependent manner and plays a role in regulating of mGluR1a signaling and intracellular trafficking in human embryonic kidney 293 cells. Specifically, Rab8 expression attenuates mGluR1a-mediated inositol phosphate formation and calcium release from mouse neurons in a PKC-dependent manner, while increasing cell surface mGluR1a expression via decreased receptor endocytosis. These experiments provide us with an understanding of the role Rabs play in coordinated regulation of mGluR1a and how this impacts mGluR1a signaling.

  6. Signal Transduction and Intracellular Trafficking by the Interleukin 36 Receptor*

    Science.gov (United States)

    Saha, Siddhartha S.; Singh, Divyendu; Raymond, Ernest L.; Ganesan, Rajkumar; Caviness, Gary; Grimaldi, Christine; Woska, Joseph R.; Mennerich, Detlev; Brown, Su-Ellen; Mbow, M. Lamine; Kao, C. Cheng

    2015-01-01

    Improper signaling of the IL-36 receptor (IL-36R), a member of the IL-1 receptor family, has been associated with various inflammation-associated diseases. However, the requirements for IL-36R signal transduction remain poorly characterized. This work seeks to define the requirements for IL-36R signaling and intracellular trafficking. In the absence of cognate agonists, IL-36R was endocytosed and recycled to the plasma membrane. In the presence of IL-36, IL-36R increased accumulation in LAMP1+ lysosomes. Endocytosis predominantly used a clathrin-mediated pathway, and the accumulation of the IL-36R in lysosomes did not result in increased receptor turnover. The ubiquitin-binding Tollip protein contributed to IL-36R signaling and increased the accumulation of both subunits of the IL-36R. PMID:26269592

  7. Role of TARP interaction in S-SCAM-mediated regulation of AMPA receptors.

    Science.gov (United States)

    Danielson, Eric; Metallo, Jacob; Lee, Sang H

    2012-01-01

    Scaffolding proteins are involved in the incorporation, anchoring, maintenance, and removal of AMPA receptors (AMPARs) at synapses, either through a direct interaction with AMPARs or via indirect association through auxiliary subunits of transmembrane AMPAR regulatory proteins (TARPs). Synaptic scaffolding molecule (S-SCAM) is a newly characterized member of the scaffolding proteins critical for the regulation and maintenance of AMPAR levels at synapses, and directly binds to TARPs through a PDZ interaction. However, the functional significance of S-SCAM-TARP interaction in the regulation of AMPARs has not been tested. Here we show that overexpression of the C-terminal peptide of TARP-γ2 fused to EGFP abolished the S-SCAM-mediated enhancement of surface GluA2 expression. Conversely, the deletion of the PDZ-5 domain of S-SCAM that binds TARPs greatly attenuated the S-SCAM-induced increase of surface GluA2 expression. In contrast, the deletion of the guanylate kinase domain of S-SCAM did not show a significant effect on the regulation of AMPARs. Together, these results suggest that S-SCAM is regulating AMPARs through TARPs. PMID:22878254

  8. Phosphorylation of AMPA receptors is required for sensory deprivation-induced homeostatic synaptic plasticity.

    Science.gov (United States)

    Goel, Anubhuti; Xu, Linda W; Snyder, Kevin P; Song, Lihua; Goenaga-Vazquez, Yamila; Megill, Andrea; Takamiya, Kogo; Huganir, Richard L; Lee, Hey-Kyoung

    2011-01-01

    Sensory experience, and the lack thereof, can alter the function of excitatory synapses in the primary sensory cortices. Recent evidence suggests that changes in sensory experience can regulate the synaptic level of Ca(2+)-permeable AMPA receptors (CP-AMPARs). However, the molecular mechanisms underlying such a process have not been determined. We found that binocular visual deprivation, which is a well-established in vivo model to produce multiplicative synaptic scaling in visual cortex of juvenile rodents, is accompanied by an increase in the phosphorylation of AMPAR GluR1 (or GluA1) subunit at the serine 845 (S845) site and the appearance of CP-AMPARs at synapses. To address the role of GluR1-S845 in visual deprivation-induced homeostatic synaptic plasticity, we used mice lacking key phosphorylation sites on the GluR1 subunit. We found that mice specifically lacking the GluR1-S845 site (GluR1-S845A mutants), which is a substrate of cAMP-dependent kinase (PKA), show abnormal basal excitatory synaptic transmission and lack visual deprivation-induced homeostatic synaptic plasticity. We also found evidence that increasing GluR1-S845 phosphorylation alone is not sufficient to produce normal multiplicative synaptic scaling. Our study provides concrete evidence that a GluR1 dependent mechanism, especially S845 phosphorylation, is a necessary pre-requisite step for in vivo homeostatic synaptic plasticity.

  9. Phosphorylation of AMPA receptors is required for sensory deprivation-induced homeostatic synaptic plasticity.

    Directory of Open Access Journals (Sweden)

    Anubhuti Goel

    Full Text Available Sensory experience, and the lack thereof, can alter the function of excitatory synapses in the primary sensory cortices. Recent evidence suggests that changes in sensory experience can regulate the synaptic level of Ca(2+-permeable AMPA receptors (CP-AMPARs. However, the molecular mechanisms underlying such a process have not been determined. We found that binocular visual deprivation, which is a well-established in vivo model to produce multiplicative synaptic scaling in visual cortex of juvenile rodents, is accompanied by an increase in the phosphorylation of AMPAR GluR1 (or GluA1 subunit at the serine 845 (S845 site and the appearance of CP-AMPARs at synapses. To address the role of GluR1-S845 in visual deprivation-induced homeostatic synaptic plasticity, we used mice lacking key phosphorylation sites on the GluR1 subunit. We found that mice specifically lacking the GluR1-S845 site (GluR1-S845A mutants, which is a substrate of cAMP-dependent kinase (PKA, show abnormal basal excitatory synaptic transmission and lack visual deprivation-induced homeostatic synaptic plasticity. We also found evidence that increasing GluR1-S845 phosphorylation alone is not sufficient to produce normal multiplicative synaptic scaling. Our study provides concrete evidence that a GluR1 dependent mechanism, especially S845 phosphorylation, is a necessary pre-requisite step for in vivo homeostatic synaptic plasticity.

  10. MAGI-1 modulates AMPA receptor synaptic localization and behavioral plasticity in response to prior experience.

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    Lesley Emtage

    Full Text Available It is well established that the efficacy of synaptic connections can be rapidly modified by neural activity, yet how the environment and prior experience modulate such synaptic and behavioral plasticity is only beginning to be understood. Here we show in C. elegans that the broadly conserved scaffolding molecule MAGI-1 is required for the plasticity observed in a glutamatergic circuit. This mechanosensory circuit mediates reversals in locomotion in response to touch stimulation, and the AMPA-type receptor (AMPAR subunits GLR-1 and GLR-2, which are required for reversal behavior, are localized to ventral cord synapses in this circuit. We find that animals modulate GLR-1 and GLR-2 localization in response to prior mechanosensory stimulation; a specific isoform of MAGI-1 (MAGI-1L is critical for this modulation. We show that MAGI-1L interacts with AMPARs through the intracellular domain of the GLR-2 subunit, which is required for the modulation of AMPAR synaptic localization by mechanical stimulation. In addition, mutations that prevent the ubiquitination of GLR-1 prevent the decrease in AMPAR localization observed in previously stimulated magi-1 mutants. Finally, we find that previously-stimulated animals later habituate to subsequent mechanostimulation more rapidly compared to animals initially reared without mechanical stimulation; MAGI-1L, GLR-1, and GLR-2 are required for this change in habituation kinetics. Our findings demonstrate that prior experience can cause long-term alterations in both behavioral plasticity and AMPAR localization at synapses in an intact animal, and indicate a new, direct role for MAGI/S-SCAM proteins in modulating AMPAR localization and function in the wake of variable sensory experience.

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

    Directory of Open Access Journals (Sweden)

    Matthew T C Brown

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  12. ANTIDEPRESSANT-LIKE EFFECTS OF LOW KETAMINE DOSE IS ASSOCIATED WITH INCREASED HIPPOCAMPAL AMPA/NMDA RECEPTOR DENSITY RATIO IN FEMALE WISTAR-KYOTO RATS

    Science.gov (United States)

    Tizabi, Yousef; Bhatti, Babur H; Manaye, Kebreten F; Das, Jharna R; Akinfiresoye, Luli

    2012-01-01

    Preclinical as well as limited clinical studies indicate that ketamine, a non-competitive glutamate NMDA receptor antagonist, may exert a quick and prolonged antidepressant effect. It has been postulated that ketamine action is due to inhibition of NMDA and stimulation of AMPA receptors. Here, we sought to determine whether ketamine would exert antidepressant effects in Wistar-Kyoto (WKY) rats, a putative animal model of depression and whether this effect would be associated with changes in AMPA/NMDA receptor densities in the hippocampus. Adult female WKY rats and their control Wistar rats were subjected to acute and chronic ketamine doses and their locomotor activity (LMA) and immobility in the forced swim test (FST) were evaluated. Hippocampal AMPA and NMDA receptor densities were also measured following a chronic ketamine dose. Ketamine, both acutely (0.5–5.0 mg/kg ip) and chronically (0.5–2.5 mg/kg daily for 10 days) resulted in a dose-dependent and prolonged decrease in immobility in the FST in WKY rats only, suggesting an antidepressant-like effect in this model. Chronic treatment with an effective dose of ketamine also resulted in an increase in AMPA/NMDA receptor density ratio in the hippocampus of WKY rats. LMA was not affected by any ketamine treatment in either strain. These results indicate a rapid and lasting antidepressant-like effect of a low ketamine dose in WKY rat model of depression. Moreover, the increase in AMPA/NMDA receptor density in hippocampus could be a contributory factor to behavioral effects of ketamine. These findings suggest potential therapeutic benefit in simultaneous reduction of central NMDA and elevation of AMPA receptor function in treatment of depression. PMID:22521815

  13. Synthesis of AMPA Receptor Antagonist NS1209%AMPA受体拮抗剂NS1209的合成

    Institute of Scientific and Technical Information of China (English)

    杨海超; 葛敏

    2011-01-01

    A AMPA receptor antagonist, NS1209, was synthesized from 5-bromo-isoquinoline by a nine-step reaction in overall yield of 37.3%. The structure was confirmed by 1H NMR and MS.%以5-溴异喹啉为起始原料,经过9步反应合成了AMPA受体拮抗剂——NS1209,总产率37.3%,其结构经1H NMR和MS确证.

  14. Interdependent epidermal growth factor receptor signalling and trafficking.

    Science.gov (United States)

    Jones, Sylwia; Rappoport, Joshua Z

    2014-06-01

    Epidermal growth factor (EGF) receptor (EGFR) signalling regulates diverse cellular functions, promoting cell proliferation, differentiation, migration, cell growth and survival. EGFR signalling is critical during embryogenesis, in particular in epithelial development, and disruption of the EGFR gene results in epithelial immaturity and perinatal death. EGFR signalling also functions during wound healing responses through accelerating wound re-epithelialisation, inducing cell migration, proliferation and angiogenesis. Upregulation of EGFR signalling is often observed in carcinomas and has been shown to promote uncontrolled cell proliferation and metastasis. Therefore aberrant EGFR signalling is a common target for anticancer therapies. Various reports indicate that EGFR signalling primarily occurs at the plasma membrane and EGFR degradation following endocytosis greatly attenuates signalling. Other studies argue that EGFR internalisation is essential for complete activation of downstream signalling cascades and that endosomes can serve as signalling platforms. The aim of this review is to discuss current understanding of intersection between EGFR signalling and trafficking. PMID:24681003

  15. Hypothermia rescues hippocampal CA1 neurons and attenuates down-regulation of the AMPA receptor GluR2 subunit after forebrain ischemia

    OpenAIRE

    Colbourne, Frederick; Grooms, Sonja Y.; Zukin, R. Suzanne; Buchan, Alastair M.; Bennett, Michael V. L.

    2003-01-01

    Brief forebrain ischemia in rodents induces selective and delayed neuronal death, particularly of hippocampal CA1 pyramidal neurons. Neuronal death is preceded by down-regulation specific to CA1 of GluR2, the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit that limits Ca2+ influx. This alteration is hypothesized to cause neurodegeneration by permitting a lethal influx of Ca2+ and/or Zn2+ through newly formed GluR2-lacking AMPA receptors. Two days of mild hypotherm...

  16. Long-Term Potentiation: From CaMKII to AMPA Receptor Trafficking.

    Science.gov (United States)

    Herring, Bruce E; Nicoll, Roger A

    2016-01-01

    For more than 20 years, we have known that Ca(2+)/calmodulin-dependent protein kinase (CaMKII) activation is both necessary and sufficient for the induction of long-term potentiation (LTP). During this time, tremendous effort has been spent in attempting to understand how CaMKII activation gives rise to this phenomenon. Despite such efforts, there is much to be learned about the molecular mechanisms involved in LTP induction downstream of CaMKII activation. In this review, we highlight recent developments that have shaped our current thinking about the molecular mechanisms underlying LTP and discuss important questions that remain in the field. PMID:26863325

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Role of AMPA and GluR5 kainate receptors in the development and expression of amygdala kindling in the mouse.

    Science.gov (United States)

    Rogawski, M A; Kurzman, P S; Yamaguchi, S I; Li, H

    2001-01-01

    The role of AMPA and GluR5-containing kainate receptors in the development and expression of amygdala kindling was examined using the selective 2,3-benzodiazepine AMPA receptor antagonist GYKI 52466 [(1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2, 3-benzodiazepine] and the decahydroisoquinoline mixed AMPA receptor and GluR5 kainate receptor antagonist LY293558 {(3S,4aR,6R, 8aR)-6-[2-(1(2)H-tetrazole-5-yl)ethyl]decahydroisoquinoline- 3-carboxy lic acid)}. Administration of GYKI 52466 (5-40 mg/kg, intraperitoneally) and LY293558 (10-40 mg/kg, intraperitoneally) prior to daily kindling stimulation in mice produced a dose-dependent suppression of the rate of development of behavioral kindled seizure activity and reduced the duration of the stimulation-induced electrographic afterdischarge. In drug-free stimulation sessions after the initial drug-treatment sessions, there was an acceleration in the rate of kindling development compared with the rate during the preceding drug-administration period; the "rebound" rate was also greater than the kindling rate in saline-treated control animals. In fully kindled animals, both GYKI 52466 and LY293558 produced a dose-dependent suppression of evoked seizures (ED(50), 19.3 and 16.7 mg/kg, respectively). Although AMPA receptors appear to be critical to the expression of kindled seizures, since kindling development progressed despite the suppression of behavioral seizure activity, AMPA receptors are less important to the kindling process. LY293558 was modestly less effective at suppressing behavioral seizures during kindling and was not superior to GYKI 52466 in retarding the overall extent of kindling development, indicating that GluR5 kainate receptors do not contribute to epileptogenesis in this model.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Intracellular Ca2+ and not the extracellular matrix determines surface dynamics of AMPA-type glutamate receptors on aspiny neurons

    Science.gov (United States)

    Klueva, Julia; Gundelfinger, Eckart D.; Frischknecht, R. Renato; Heine, Martin

    2014-01-01

    The perisynaptic extracellular matrix (ECM) contributes to the control of the lateral mobility of AMPA-type glutamate receptors (AMPARs) at spine synapses of principal hippocampal neurons. Here, we have studied the effect of the ECM on the lateral mobility of AMPARs at shaft synapses of aspiny interneurons. Single particle tracking experiments revealed that the removal of the hyaluronan-based ECM with hyaluronidase does not affect lateral receptor mobility on the timescale of seconds. Similarly, cross-linking with specific antibodies against the extracellular domain of the GluA1 receptor subunit, which affects lateral receptor mobility on spiny neurons, does not influence receptor mobility on aspiny neurons. AMPARs on aspiny interneurons are characterized by strong inward rectification indicating a significant fraction of Ca2+-permeable receptors. Therefore, we tested whether Ca2+ controls AMPAR mobility in these neurons. Application of the membrane-permeable Ca2+ chelator BAPTA-AM significantly increased the lateral mobility of GluA1-containing synaptic and extrasynaptic receptors. These data indicate that the perisynaptic ECM affects the lateral mobility differently on spiny and aspiny neurons. Although ECM structures on interneurons appear much more prominent, their influence on AMPAR mobility seems to be negligible at short timescales. PMID:25225098

  1. 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.

  2. Requirement of AMPA receptor stimulation for the sustained antidepressant activity of ketamine and LY341495 during the forced swim test in rats.

    Science.gov (United States)

    Koike, Hiroyuki; Chaki, Shigeyuki

    2014-09-01

    Ketamine, a non-competitive N-methyl-d-aspartate receptor antagonist, and group II metabotropic glutamate (mGlu2/3) receptor antagonists produce antidepressant effects in animal models of depression, which last for at least 24h, through the transient increase in glutamate release, leading to activation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor. Both ketamine and an mGlu2/3 receptor antagonist reportedly increase the expression of GluR1, an AMPA receptor subunit, within 24h, which may account for the sustained enhancement of excitatory synaptic transmission following ketamine administration. However, whether the sustained increase in AMPA receptor-mediated synaptic transmission is associated with the antidepressant effects of ketamine and mGlu2/3 receptor antagonists has not yet been investigated. In the present study, to address this question, we tested whether AMPA receptor stimulation at 24h after a single injection of ketamine or an mGlu2/3 receptor antagonist, (2S)-2-amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl)propanoic acid (LY341495) was necessary for the antidepressant effect of these compounds using a forced swim test in rats. A single injection of ketamine or LY341495 at 24h before the test significantly decreased the immobility time. An AMPA receptor antagonist, 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX), administered 30min prior to the test significantly and dose-dependently reversed the antidepressant effects of ketamine and LY341495, while NBQX itself had no effect on the immobility time. Our findings suggest that AMPA receptor stimulation at 24h after a single injection of ketamine or LY341495 is required to produce the anti-immobility effects of these compounds. Moreover, the present results provide additional evidence that an mGlu2/3 receptor antagonist may share some of neural mechanisms with ketamine to exert antidepressant effects.

  3. Functional Consequences of Glucagon-like Peptide-1 Receptor Cross-talk and Trafficking

    DEFF Research Database (Denmark)

    Roed, Sarah Noerklit; Nøhr, Anne Cathrine; Wismann, Pernille;

    2015-01-01

    The signaling capacity of seven-transmembrane/G-protein-coupled receptors (7TM/GPCRs) can be regulated through ligand-mediated receptor trafficking. Classically, the recycling of internalized receptors is associated with resensitization, whereas receptor degradation terminates signaling. We have......) and glucagon (GCGR) receptors. The interaction and cross-talk between coexpressed receptors is a wide phenomenon of the 7TM/GPCR superfamily. Numerous reports show functional consequences for signaling and trafficking of the involved receptors. On the basis of the high structural similarity and tissue...... coexpression, we here investigated the potential cross-talk between GLP-1R and GIPR or GCGR in both trafficking and signaling pathways. Using a real-time time-resolved FRET-based internalization assay, we show that GLP-1R, GIPR, and GCGR internalize with differential properties. Remarkably, upon coexpression...

  4. A new phenylalanine derivative acts as an antagonist at the AMPA receptor GluA2 and introduces partial domain closure

    DEFF Research Database (Denmark)

    Szymanska, Ewa; Frydenvang, Karla; Contreras-Sanz, Alberto;

    2011-01-01

    In order to map out molecular determinants for competitive blockade of AMPA receptor subtypes, a series of 2-carboxyethylphenylalanine derivatives has been synthesized and pharmacologically characterized in vitro. One compound in this series, (RS)-3h, showed micromolar affinity for GluA1(o) and G...

  5. Current progress of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptor trafficking in learning and memory%α-氨基-3羟基-5-甲基-4-异恶唑丙酸受体运输参与学习记忆机制的研究进展

    Institute of Scientific and Technical Information of China (English)

    王苗苗; 王超; 杨美华; 王国林

    2014-01-01

    Background α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptors mediate the overwhelming majority of excitatory synaptic transmission in the central nervous system.Postsynaptic AMPA receptor trafficking is closely related to learning and memory.Objective To review the relationship between postsynaptic AMPA receptor trafficking and learning and memory.Content This review introduces the changes of AMPA receptor trafficking and the underlying mechanisms in long-term potentiation (LTP) and long-term depression (LTD)-the two most characterized forms of synaptic plasticity.Both forms of synaptic plasticity are thought to be the cellular basis of learning and memory.The phosphorylation of multiple proteins and the modification of related signaling molecules and pathways are involved in these processes.The role of AMPA receptor trafficking in learning and memory behavior is also discussed.Trend To provide new ideas for dissecting the mechanisms of learning and memory related neurodegenerative diseases.%背景 α-氨基-3羟基-5-甲基-4-异恶唑丙酸(α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptor,AMPA)受体介导中枢神经系统大多数兴奋性突触传递,其在突触后膜的运输与学习记忆密切相关. 目的 对AMPA受体在突触后膜的运输与学习记忆的关系作用进行归纳和小结. 内容 介绍AMPA受体运输在学习记忆的重要细胞学基础-突触可塑性的两种主要形式长时程增强(long-term potentiation,LTP)和长时程抑制(long-term depression,LTD)中的改变及其可能机制,涉及多个蛋白的磷酸化和参与调节其改变的信号分子及通路,并说明AMPA受体运输参与相关的学习记忆行为. 趋向 为学习记忆受损相关神经退行性疾病的发生机制的探索提供思路.

  6. Multiple Routes for Glutamate Receptor Trafficking: Surface Diffusion and Membrane Traffic Cooperate to Bring Receptors to Synapses

    CERN Document Server

    Cognet, Laurent; Lounis, Brahim; Choquet, Daniel

    2006-01-01

    Trafficking of glutamate receptors into and out of synapses is critically involved in the plasticity of excitatory synaptic transmission. Endocytosis and exocytosis of receptors have initially been thought to account alone for this trafficking. However, membrane proteins also traffic through surface lateral diffusion in the plasma membrane. We describe developments in electrophysiological and optical approaches that have allowed for the real time measurement of glutamate receptor surface trafficking in live neurons. These include (i) specific imaging of surface receptors using a pH sensitive fluorescent protein, (ii) design of a photoactivable drug to inactivate locally surface receptors and monitor electrophysiologically their recovery, and (iii)application of single molecule fluorescence microscopy to directly track the movement of individual surface receptors with nanometer resolution inside and outside synapses. Altogether, these approaches have demonstrated that glutamate receptors diffuse at high rates ...

  7. Polarized Trafficking of the Sorting Receptor SorLA in Neurons and MDCK Cells

    DEFF Research Database (Denmark)

    Klinger, Stine C; Højland, Anne; Jain, Shweta;

    2016-01-01

    The sorting receptor SorLA is highly expressed in neurons and is also found in other polarized cells. The receptor has been reported to participate in the trafficking of several ligands, some of which are linked to human diseases, including the amyloid precursor protein, TrkB and lipoprotein lipase...... (LpL). Despite this, only the trafficking in non-polarized cells has been described so far. Due to the many differences between polarized and non-polarized cells, we examined the localization and trafficking of SorLA in epithelial Madin-Darby canine kidney (MDCK) cells and rat hippocampal neurons. We...

  8. 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.

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

    Science.gov (United States)

    Quaranta, Giuseppe; Maremmani, Angelo Giovanni Icro; Perugi, Giulio

    2015-01-01

    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. PMID:26495149

  10. 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.

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

    Science.gov (United States)

    Quaranta, Giuseppe; Maremmani, Angelo Giovanni Icro; Perugi, Giulio

    2015-01-01

    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. PMID:26495149

  12. Endocytosis and Trafficking of Natriuretic Peptide Receptor-A: Potential Role of Short Sequence Motifs

    Directory of Open Access Journals (Sweden)

    Kailash N. Pandey

    2015-07-01

    Full Text Available The targeted endocytosis and redistribution of transmembrane receptors among membrane-bound subcellular organelles are vital for their correct signaling and physiological functions. Membrane receptors committed for internalization and trafficking pathways are sorted into coated vesicles. Cardiac hormones, atrial and brain natriuretic peptides (ANP and BNP bind to guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA and elicit the generation of intracellular second messenger cyclic guanosine 3',5'-monophosphate (cGMP, which lowers blood pressure and incidence of heart failure. After ligand binding, the receptor is rapidly internalized, sequestrated, and redistributed into intracellular locations. Thus, NPRA is considered a dynamic cellular macromolecule that traverses different subcellular locations through its lifetime. The utilization of pharmacologic and molecular perturbants has helped in delineating the pathways of endocytosis, trafficking, down-regulation, and degradation of membrane receptors in intact cells. This review describes the investigation of the mechanisms of internalization, trafficking, and redistribution of NPRA compared with other cell surface receptors from the plasma membrane into the cell interior. The roles of different short-signal peptide sequence motifs in the internalization and trafficking of other membrane receptors have been briefly reviewed and their potential significance in the internalization and trafficking of NPRA is discussed.

  13. Resolution, configurational assignment, and enantiopharmacology of 2-amino-3-[3-hydroxy-5-(2-methyl-2H- tetrazol-5-yl)isoxazol-4-yl]propionic acid, a potent GluR3- and GluR4-preferring AMPA receptor agonist

    DEFF Research Database (Denmark)

    Vogensen, S B; Jensen, H S; Stensbøl, T B;

    2000-01-01

    We have previously shown that (RS)-2-amino-3-[3-hydroxy-5-(2-methyl-2H-tetrazol-5-yl)isoxazol -4-yl] propionic acid (2-Me-Tet-AMPA) is a selective agonist at (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors, markedly more potent than AMPA itself, whereas the isomeric...

  14. The Role of Rab Proteins in Neuronal Cells and in the Trafficking of Neurotrophin Receptors

    Directory of Open Access Journals (Sweden)

    Cecilia Bucci

    2014-10-01

    Full Text Available Neurotrophins are a family of proteins that are important for neuronal development, neuronal survival and neuronal functions. Neurotrophins exert their role by binding to their receptors, the Trk family of receptor tyrosine kinases (TrkA, TrkB, and TrkC and p75NTR, a member of the tumor necrosis factor (TNF receptor superfamily. Binding of neurotrophins to receptors triggers a complex series of signal transduction events, which are able to induce neuronal differentiation but are also responsible for neuronal maintenance and neuronal functions. Rab proteins are small GTPases localized to the cytosolic surface of specific intracellular compartments and are involved in controlling vesicular transport. Rab proteins, acting as master regulators of the membrane trafficking network, play a central role in both trafficking and signaling pathways of neurotrophin receptors. Axonal transport represents the Achilles' heel of neurons, due to the long-range distance that molecules, organelles and, in particular, neurotrophin-receptor complexes have to cover. Indeed, alterations of axonal transport and, specifically, of axonal trafficking of neurotrophin receptors are responsible for several human neurodegenerative diseases, such as Huntington’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis and some forms of Charcot-Marie-Tooth disease. In this review, we will discuss the link between Rab proteins and neurotrophin receptor trafficking and their influence on downstream signaling pathways.

  15. The Prefrontal Dectin-1/AMPA Receptor Signaling Pathway Mediates The Robust and Prolonged Antidepressant Effect of Proteo-β-Glucan from Maitake

    Science.gov (United States)

    Bao, Hongkun; Ran, Pengzhan; Zhu, Ming; Sun, Lijuan; Li, Bai; Hou, Yangyang; Nie, Jun; Shan, Liping; Li, Hongliang; Zheng, Shangyong; Xu, Xiufeng; Xiao, Chunjie; Du, Jing

    2016-01-01

    Proteo-β-glucan from Maitake (PGM) is a strong immune regulator, and its receptor is called Dectin-1. Cumulative evidence suggests that AMPA receptors are important for the treatment of depression. Here, we report that PGM treatment leads to a significant antidepressant effect in the tail suspension test and forced swim test after sixty minutes of treatment in mice. After five consecutive days of PGM treatment, this antidepressant effect remained. PGM treatment did not show a hyperactive effect in the open field test. PGM significantly enhanced the expression of its receptor Dectin-1, as well as p-GluA1(S845) and GluA1, but not GluA2 or GluA3 in the prefrontal cortex (PFC) after five days of treatment. The Dectin-1 inhibitor Laminarin was able to block the antidepressant effect of PGM. At the synapses of PFC, PGM treatment significantly up-regulated the p-GluA1(S845), GluA1, GluA2, and GluA3 levels. Moreover, PGM’s antidepressant effects and the increase of p-GluA1(S845)/GluA1 lasted for 3 days after stopping treatment. The AMPA-specific antagonist GYKI 52466 was able to block the antidepressant effect of PGM. This study identified PGM as a novel antidepressant with clinical potential and a new antidepressant mechanism for regulating prefrontal Dectin-1/AMPA receptor signalling. PMID:27329257

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Alteration of AMPA Receptor-Mediated Synaptic Transmission by Alexa Fluor 488 and 594 in Cerebellar Stellate Cells.

    Science.gov (United States)

    Maroteaux, Matthieu; Liu, Siqiong June

    2016-01-01

    The fluorescent dyes, Alexa Fluor 488 and 594 are commonly used to visualize dendritic structures and the localization of synapses, both of which are critical for the spatial and temporal integration of synaptic inputs. However, the effect of the dyes on synaptic transmission is not known. Here we investigated whether Alexa Fluor dyes alter the properties of synaptic currents mediated by two subtypes of AMPA receptors (AMPARs) at cerebellar stellate cell synapses. In naive mice, GluA2-lacking AMPAR-mediated synaptic currents displayed an inwardly rectifying current-voltage (I-V) relationship due to blockade by cytoplasmic spermine at depolarized potentials. We found that the inclusion of 100 µm Alexa Fluor dye, but not 10 µm, in the pipette solution led to a gradual increase in the amplitude of EPSCs at +40 mV and a change in the I-V relationship from inwardly rectifying to more linear. In mice exposed to an acute stress, AMPARs switched to GluA2-containing receptors, and 100 µm Alexa Fluor 594 did not alter the I-V relationship of synaptic currents. Therefore, a high concentration of Alexa Fluor dye changed the I-V relationship of EPSCs at GluA2-lacking AMPAR synapses.

  18. Alteration of AMPA Receptor-Mediated Synaptic Transmission by Alexa Fluor 488 and 594 in Cerebellar Stellate Cells.

    Science.gov (United States)

    Maroteaux, Matthieu; Liu, Siqiong June

    2016-01-01

    The fluorescent dyes, Alexa Fluor 488 and 594 are commonly used to visualize dendritic structures and the localization of synapses, both of which are critical for the spatial and temporal integration of synaptic inputs. However, the effect of the dyes on synaptic transmission is not known. Here we investigated whether Alexa Fluor dyes alter the properties of synaptic currents mediated by two subtypes of AMPA receptors (AMPARs) at cerebellar stellate cell synapses. In naive mice, GluA2-lacking AMPAR-mediated synaptic currents displayed an inwardly rectifying current-voltage (I-V) relationship due to blockade by cytoplasmic spermine at depolarized potentials. We found that the inclusion of 100 µm Alexa Fluor dye, but not 10 µm, in the pipette solution led to a gradual increase in the amplitude of EPSCs at +40 mV and a change in the I-V relationship from inwardly rectifying to more linear. In mice exposed to an acute stress, AMPARs switched to GluA2-containing receptors, and 100 µm Alexa Fluor 594 did not alter the I-V relationship of synaptic currents. Therefore, a high concentration of Alexa Fluor dye changed the I-V relationship of EPSCs at GluA2-lacking AMPAR synapses. PMID:27280156

  19. Regulated RalBP1 binding to RalA and PSD-95 controls AMPA receptor endocytosis and LTD.

    Directory of Open Access Journals (Sweden)

    Kihoon Han

    2009-09-01

    Full Text Available Long-term depression (LTD is a long-lasting activity-dependent decrease in synaptic strength. NMDA receptor (NMDAR-dependent LTD, an extensively studied form of LTD, involves the endocytosis of AMPA receptors (AMPARs via protein dephosphorylation, but the underlying mechanism has remained unclear. We show here that a regulated interaction of the endocytic adaptor RalBP1 with two synaptic proteins, the small GTPase RalA and the postsynaptic scaffolding protein PSD-95, controls NMDAR-dependent AMPAR endocytosis during LTD. NMDAR activation stimulates RalA, which binds and translocates widespread RalBP1 to synapses. In addition, NMDAR activation dephosphorylates RalBP1, promoting the interaction of RalBP1 with PSD-95. These two regulated interactions are required for NMDAR-dependent AMPAR endocytosis and LTD and are sufficient to induce AMPAR endocytosis in the absence of NMDAR activation. RalA in the basal state, however, maintains surface AMPARs. We propose that NMDAR activation brings RalBP1 close to PSD-95 to promote the interaction of RalBP1-associated endocytic proteins with PSD-95-associated AMPARs. This suggests that scaffolding proteins at specialized cellular junctions can switch their function from maintenance to endocytosis of interacting membrane proteins in a regulated manner.

  20. Caloric Restriction Eliminates the Aging-related Declines of NMDA and AMPA Receptor Subunits in the Rat Hippocampus and Induces Homeostasis

    OpenAIRE

    Shi, Lei; Adams, Michelle M.; Linville, M. Constance; Newton, Isabel G.; Forbes, M. Elizabeth; Long, Ashley; Riddle, David R.; Brunso-Bechtold, Judy K.

    2007-01-01

    Caloric restriction (CR) extends lifespan and ameliorates the aging-related decline in hippocampal-dependent cognitive function. In the present study, we compared subunit levels of NMDA and AMPA types of the glutamate receptor and quantified total synapses and multiple spine bouton (MSB) synapses in hippocampal CA1 from young (10 months), middle-aged (18 months), and old (29 months) Fischer 344 x Brown Norway rats that were ad libitum (AL) fed or caloric restricted (CR) from 4 months of age. ...

  1. Alteration of AMPA Receptor-Mediated Synaptic Transmission by Alexa Fluor 488 and 594 in Cerebellar Stellate Cells1 2 3

    OpenAIRE

    Maroteaux, Matthieu; Liu, Siqiong June

    2016-01-01

    Abstract The fluorescent dyes, Alexa Fluor 488 and 594 are commonly used to visualize dendritic structures and the localization of synapses, both of which are critical for the spatial and temporal integration of synaptic inputs. However, the effect of the dyes on synaptic transmission is not known. Here we investigated whether Alexa Fluor dyes alter the properties of synaptic currents mediated by two subtypes of AMPA receptors (AMPARs) at cerebellar stellate cell synapses. In naive mice, GluA...

  2. Post-transcriptional mechanisms of regulation of AMPA receptors : regulation of GluA1 expression by the contactin associated protein 1

    OpenAIRE

    Fernandes, Dominique Moreira

    2011-01-01

    No sistema nervoso central, a maior parte da neurotransmissão excitatória é mediada por receptores de glutamato do tipo AMPA que possuem papéis fundamentais na plasticidade sináptica, o fenómeno celular na base de processos de aprendizagem e memória. Modificações no tráfego destes receptores e na sua inserção ao nível das sinapses, bem como na estabilidade do RNA mensageiro das subunidades dos receptores ou no seu decaimento, são cruciais para induzir alterações de longo prazo ...

  3. Differential Regulation of Kainate Receptor Trafficking by Phosphorylation of Distinct Sites on GluR6*

    OpenAIRE

    Nasu-Nishimura, Yukiko; Jaffe, Howard; Isaac, John T R; Roche, Katherine W.

    2009-01-01

    Kainate receptors are widely expressed in the brain, and are present at pre- and postsynaptic sites where they play a prominent role in synaptic plasticity and the regulation of network activity. Within individual neurons, kainate receptors of different subunit compositions are targeted to various locations where they serve distinct functional roles. Despite this complex targeting, relatively little is known about the molecular mechanisms regulating kainate receptor subunit trafficking. Here ...

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

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. An Integrated Model of Epidermal Growth Factor Receptor Trafficking and Signal Transduction

    Energy Technology Data Exchange (ETDEWEB)

    Resat, Haluk; Ewald, Jonathan A.; Dixon, David A.; Wiley, H. S.

    2003-08-01

    Endocytic trafficking of many types of receptors can have profound effects on subsequent signaling events. Quantitative models of these processes, however, have usually considered trafficking and signaling independently. Here, we present an integrated model of both the trafficking and signaling pathway of the epidermal growth factor receptor (EGFR) using a probability weighted-dynamic Monte Carlo simulation. Our model consists of hundreds of distinct endocytic compartments and about 13,000 reactions/events that occur over a broad spatio-temporal range. By using a realistic multi-compartment model, we can investigate the distribution of the receptors among cellular compartments as well as their potential signal transduction characteristics. Our new model also allows the incorporation of physio-chemical aspects of ligand-receptor interactions, such as pH-dependent binding in different endosomal compartments. To determine the utility of this approach, we simulated the differential activation of the EGFR by two of its ligands, epidermal growth factor (EGF) and transforming growth factor- alpha (TGF-a). Our simulations predict that when EGFR is activated with TGF-a, receptor activation is biased toward the cell surface whereas EGF produces a signaling bias towards the endosomal compartment. Experiments confirm these predictions from our model and simulations. Our model accurately predicts the kinetics and extent of receptor down-regulation induced by either EGF or TGF-a. Our results suggest that receptor trafficking controls the compartmental bias of signal transduction, rather than simply modulating signal magnitude. Our model provides a new approach to evaluating the complex effect of receptor trafficking on signal transduction. Importantly, the stochastic and compartmental nature of the simulation allows these models to be directly tested by high-throughput approaches, such as quantitative image analysis.

  7. An integrated model of epidermal growth factor receptor trafficking and signal transduction.

    Science.gov (United States)

    Resat, Haluk; Ewald, Jonathan A; Dixon, David A; Wiley, H Steven

    2003-08-01

    Endocytic trafficking of many types of receptors can have profound effects on subsequent signaling events. Quantitative models of these processes, however, have usually considered trafficking and signaling independently. Here, we present an integrated model of both the trafficking and signaling pathway of the epidermal growth factor receptor (EGFR) using a probability weighted-dynamic Monte Carlo simulation. Our model consists of hundreds of distinct endocytic compartments and approximately 13,000 reactions/events that occur over a broad spatio-temporal range. By using a realistic multicompartment model, we can investigate the distribution of the receptors among cellular compartments as well as their potential signal transduction characteristics. Our new model also allows the incorporation of physiochemical aspects of ligand-receptor interactions, such as pH-dependent binding in different endosomal compartments. To determine the utility of this approach, we simulated the differential activation of the EGFR by two of its ligands, epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha). Our simulations predict that when EGFR is activated with TGF-alpha, receptor activation is biased toward the cell surface whereas EGF produces a signaling bias toward the endosomal compartment. Experiments confirm these predictions from our model and simulations. Our model accurately predicts the kinetics and extent of receptor downregulation induced by either EGF or TGF-alpha. Our results suggest that receptor trafficking controls the compartmental bias of signal transduction, rather than simply modulating signal magnitude. Our model provides a new approach to evaluating the complex effect of receptor trafficking on signal transduction. Importantly, the stochastic and compartmental nature of the simulation allows these models to be directly tested by high-throughput approaches, such as quantitative image analysis. PMID:12885624

  8. Mutations in ionotropic AMPA receptor 3 alter channel properties and are associated with moderate cognitive impairment in humans.

    Science.gov (United States)

    Wu, Ye; Arai, Amy C; Rumbaugh, Gavin; Srivastava, Anand K; Turner, Gillian; Hayashi, Takashi; Suzuki, Erika; Jiang, Yuwu; Zhang, Lilei; Rodriguez, Jayson; Boyle, Jackie; Tarpey, Patrick; Raymond, F Lucy; Nevelsteen, Joke; Froyen, Guy; Stratton, Mike; Futreal, Andy; Gecz, Jozef; Stevenson, Roger; Schwartz, Charles E; Valle, David; Huganir, Richard L; Wang, Tao

    2007-11-13

    Ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (iGluRs) mediate the majority of excitatory synaptic transmission in the CNS and are essential for the induction and maintenance of long-term potentiation and long-term depression, two cellular models of learning and memory. We identified a genomic deletion (0.4 Mb) involving the entire GRIA3 (encoding iGluR3) by using an X-array comparative genomic hybridization (CGH) and four missense variants (G833R, M706T, R631S, and R450Q) in functional domains of iGluR3 by sequencing 400 males with X-linked mental retardation (XLMR). Three variants were found in males with moderate MR and were absent in 500 control males. Expression studies in HEK293 cells showed that G833R resulted in a 78% reduction of iGluR3 due to protein misfolding. Whole-cell recording studies of iGluR3 homomers in HEK293 cells revealed that neither iGluR3-M706T (S2 domain) nor iGluR3-R631S (near channel core) had substantial channel function, whereas R450Q (S1 domain) was associated with accelerated receptor desensitization. When forming heteromeric receptors with iGluR2 in HEK293 cells, all four iGluR3 variants had altered desensitization kinetics. Our study provides the genetic and functional evidence that mutant iGluR3 with altered kinetic properties is associated with moderate cognitive impairment in humans.

  9. Embryonic expression of zebrafish AMPA receptor genes: zygotic gria2alpha expression initiates at the midblastula transition.

    Science.gov (United States)

    Lin, Wei-Hsiang; Wu, Chan-Hwa; Chen, Yu-Chia; Chow, Wei-Yuan

    2006-09-19

    The AMPA-preferring receptors (AMPARs) mediate rapid excitatory synaptic transmission in the central nervous system of vertebrates. Expression profiles of 8 AMPAR genes were studied by RT-PCR analyses to elucidate the properties of AMPARs during early zebrafish development. Transcripts of all AMPAR genes are detected at the time of fertilization, suggesting maternal transcriptions of zebrafish AMPAR genes. The amounts of gria1 and gria2 transcripts are several-fold higher than that of gria3 and gria4 between 10 and 72 hpf (hour postfertilization). The edited gria2alpha transcript decreases during gastrulation period, suggesting that zygotic expression of gria2alpha begins around the time of midblastula transition. Relative to the amount of beta-actin, the amounts of AMPAR transcripts increase significantly after the completion of neurulation. The amounts of gria2 transcripts exceed the total amounts of the remaining AMPAR transcripts after 36 hpf, suggesting increases in the representation of low Ca2+ permeable AMPARs during neuronal maturation. Many but not all of the known mammalian protein-protein interaction motifs are preserved in the C-terminal domains (CTD) of zebrafish AMPARs. Before 16 hpf, the embryos express predominantly the alternative splice forms encoding longer CTD. Representations of the short CTD splice forms of gria2 and gria4alpha increase after 24 hpf, when neurulation is nearly completed.

  10. Synthetic and endogenous cannabinoids protect retinal neurons from AMPA excitotoxicity in vivo, via activation of CB1 receptors: Involvement of PI3K/Akt and MEK/ERK signaling pathways.

    Science.gov (United States)

    Kokona, Despina; Thermos, Kyriaki

    2015-07-01

    Cannabinoids have been suggested to protect retinal ganglion cells in different models of toxicity, but their effects on other retinal neurons are poorly known. We investigated the neuroprotective actions of the endocannabinoid N-arachidonoyl ethanolamine (Anandamide/AEA) and the synthetic cannabinoids R1-Methanandamide (MethAEA) and HU-210, in an in vivo retinal model of AMPA excitotoxicity, and the mechanisms involved in the neuroprotection. Sprague-Dawley rats were intravitreally injected with PBS or AMPA in the absence or presence of the cannabinoid agonists. Brain nitric oxide synthase (bNOS) and choline acetyltransferase (ChAT) immunoreactivity (IR), as well as TUNEL staining, assessed the AMPA-induced retinal amacrine cell loss and the dose-dependent neuroprotection afforded by cannabinoids. The CB1 receptor selective antagonist AM251 and the PI3K/Akt inhibitor wortmannin reversed the cannabinoid-induced neuroprotection, suggesting the involvement of CB1 receptors and the PI3K/Akt pathway in cannabinoids' actions. Experiments with the CB2 agonist JWH015 and [(3)H]CP55940 radioligand binding suggested that the CB2 receptor is not involved in the neuroprotection. AEA and HU-210 induced phosphorylation of Akt but only AEA induced phosphorylation of ERK1/2 kinases, as revealed by western blot analysis. To investigate the role of caspase-3 in the AMPA-induced cell death, the caspase-3 inhibitor Z-DEVD-FMK was co-injected with AMPA. Z-DEVD-FMK had no effect on AMPA excitotoxicity. Moreover, no difference was observed in the phosphorylation of SAPK/JNK kinases between PBS- and AMPA-treated retinas. These results suggest that endogenous and synthetic cannabinoids protect retinal amacrine neurons from AMPA excitotoxicity in vivo via a mechanism involving the CB1 receptors, and the PI3K/Akt and/or MEK/ERK1/2 signaling pathways.

  11. Differential expression of postsynaptic NMDA and AMPA receptor subunits in the hippocampus and prefrontal cortex of the flinders sensitive line rat model of depression.

    Science.gov (United States)

    Treccani, Giulia; Gaarn du Jardin, Kristian; Wegener, Gregers; Müller, Heidi Kaastrup

    2016-11-01

    Glutamatergic abnormalities have recently been implicated in the pathophysiology of depression, and the ionotropic glutamate receptors in particular have been suggested as possible underlying molecular determinants. The Flinders Sensitive Line (FSL) rats constitute a validated model of depression with dysfunctional regulation of glutamate transmission relatively to their control strain Flinders Resistant Line (FRL). To gain insight into how signaling through glutamate receptors may be altered in the FSL rats, we investigated the expression and phosphorylation of AMPA and NMDA receptor subunits in an enriched postsynaptic fraction of the hippocampus and prefrontal cortex. Compared to the hippocampal postsynaptic fractions of FRL rats, FSL rats exhibited decreased and increased levels of the NMDA receptor subunits GluN2A and GluN2B, respectively, causing a lower ratio of GluN2A/GluN2B. The GluA2/GluA3 AMPA receptor subunit ratio was significantly decreased while the expression of the individual GluA1, GluA2, and GluA3 subunits were unaltered including phosphorylation levels of GluA1 at S831 and S845. There were no changes in the prefrontal cortex. These results support altered expression of postsynaptic glutamate receptors in the hippocampus of FSL rats, which may contribute to the depressive-like phenotype of these rats. PMID:27262028

  12. Differences in rat dorsal striatal NMDA and AMPA receptors following acute and repeated cocaine-induced locomotor activation.

    Directory of Open Access Journals (Sweden)

    Dorothy J Yamamoto

    Full Text Available Sprague-Dawley rats can be classified as low or high cocaine responders (LCRs or HCRs, respectively based on their locomotor activity induced by an acute low dose of cocaine. Upon repeated cocaine exposure, LCRs display greater locomotor sensitization, reward, and reinforcement than HCRs. Altered glutamate receptor expression in the brain reward pathway has been linked to locomotor sensitization and addiction. To determine if such changes contribute to the differential development of locomotor sensitization, we examined protein levels of total, phosphorylated, and cell surface glutamate N-methyl D-aspartate (NMDA and α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA receptors (Rs following acute or repeated cocaine (10 mg/kg, i.p. in LCRs, HCRs and saline controls. Three areas involved in the development and expression of locomotor sensitization were investigated: the ventral tegmental area (VTA, nucleus accumbens (NAc and dorsal striatum (dSTR. Our results revealed differences only in the dSTR, where we found that after acute cocaine, GluN2B(Tyr-1472 phosphorylation was significantly greater in LCRs, compared to HCRs and controls. Additionally in dSTR, after repeated cocaine, we observed significant increases in total GluA1, phosphorylated GluA1(Ser-845, and cell surface GluA1 in all cocaine-treated animals vs. controls. The acute cocaine-induced increases in NMDARs in dSTR of LCRs may help to explain the more ready development of locomotor sensitization and susceptibility to addiction-like behaviors in rats that initially exhibit little or no cocaine-induced activation, whereas the AMPAR increases after repeated cocaine may relate to recruitment of more dorsal striatal circuits and maintenance of the marked cocaine-induced locomotor activation observed in all of the rats.

  13. Trafficking of ErbB receptors and its influence on signaling

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, H. S.

    2003-03-10

    Although members of the ErbB receptor family are found predominatly at the cell surface, these receptors undergo constant cycling between the plasma membrane and the endosomal compartment. In the absence of an activating ligand, these receptors are slowly internalized (t 1/2 ~ 30 min) are quickly recycled.The constitutive degradation rate of the epidermal growth factor (EGF) receptor (EGFR) is slower than other ErbB family members and only the EGFR appears to alter its trafficking pattern in response to ligand binding. Continued...

  14. Colocalization of neurokinin-1, NMDA, and AMPA receptors on neurons of the rat nucleus tractus solitarii

    OpenAIRE

    Lin, L. H.; Taktakishvili, O. M.; Talman, W. T.

    2008-01-01

    Substance P (SP) and glutamate are implicated in cardiovascular regulation by the nucleus tractus solitarii (NTS). Our earlier studies suggest that SP, which acts at neurokinin 1 (NK1) receptors, is not a baroreflex transmitter while glutamate is. On the other hand, our recent studies showed that loss of NTS neurons expressing NK1 receptors leads to loss of baroreflex responses and increased blood pressure lability. Furthermore, studies have suggested that SP may interact with glutamate in th...

  15. 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. PMID:23349224

  16. G Proteins and their regulators in EGF receptor trafficking and mitochondrial functions

    OpenAIRE

    Tang, Tingdong

    2009-01-01

    Mechanisms involving heterotrimeric G proteins in the regulation of membrane trafficking are not well understood. Here, we reported G\\[alpha\\]s overexpression promotes ligand-dependent degradation of EGFR and G\\[alpha\\]s knockdown delays receptor degradation through interaction with RGS-PX1 and Hrs on early endosomes. These observations provide mechanistic insights into the function of G\\[alpha\\]s, RGS-PX1 and Hrs in endocytic sorting. To further understand RGS-PX1's role in EGFR trafficking ...

  17. Investigating the influence of PFC transection and nicotine on dynamics of AMPA and NMDA receptors of VTA dopaminergic neurons

    Directory of Open Access Journals (Sweden)

    Chen Ting

    2011-10-01

    Full Text Available Abstract Background All drugs of abuse, including nicotine, activate the mesocorticolimbic system that plays critical roles in nicotine reward and reinforcement development and triggers glutamatergic synaptic plasticity on the dopamine (DA neurons in the ventral tegmental area (VTA. The addictive behavior and firing pattern of the VTA DA neurons are thought to be controlled by the glutamatergic synaptic input from prefrontal cortex (PFC. Interrupted functional input from PFC to VTA was shown to decrease the effects of the drug on the addiction process. Nicotine treatment could enhance the AMPA/NMDA ratio in VTA DA neurons, which is thought as a common addiction mechanism. In this study, we investigate whether or not the lack of glutamate transmission from PFC to VTA could make any change in the effects of nicotine. Methods We used the traditional AMPA/NMDA peak ratio, AMPA/NMDA area ratio, and KL (Kullback-Leibler divergence analysis method for the present study. Results Our results using AMPA/NMDA peak ratio showed insignificant difference between PFC intact and transected and treated with saline. However, using AMPA/NMDA area ratio and KL divergence method, we observed a significant difference when PFC is interrupted with saline treatment. One possible reason for the significant effect that the PFC transection has on the synaptic responses (as indicated by the AMPA/NMDA area ratio and KL divergence may be the loss of glutamatergic inputs. The glutamatergic input is one of the most important factors that contribute to the peak ratio level. Conclusions Our results suggested that even within one hour after a single nicotine injection, the peak ratio of AMPA/NMDA on VTA DA neurons could be enhanced.

  18. Domain architecture of a calcium-permeable AMPA receptor in a ligand-free conformation

    Directory of Open Access Journals (Sweden)

    Charles R. Midgett

    2012-01-01

    Full Text Available Ligand-gated ion channels couple the free energy of agonist binding to the gating of selective transmembrane ion pores, permitting cells to regulate ion flux in response to external chemical stimuli. However, the stereochemical mechanisms responsible for this coupling remain obscure. In the case of the ionotropic glutamate receptors (iGluRs, the modular nature of receptor subunits has facilitated structural analysis of the N-terminal domain (NTD, and of multiple conformations of the ligand-binding domain (LBD. Recently, the crystallographic structure of an antagonist-bound form of the receptor was determined. However, disulfide trapping of this conformation blocks channel opening, suggesting that channel activation involves additional quaternary packing arrangements. To explore the conformational space available to iGluR channels, we report here a second, clearly distinct domain architecture of homotetrameric, calcium-permeable AMPARs, determined by single-particle electron microscopy of untagged and fluorescently tagged constructs in a ligand-free state. It reveals a novel packing of NTD dimers, and a separation of LBD dimers across a central vestibule. In this arrangement, which reconciles diverse functional observations, agonist-induced cleft closure across LBD dimers can be converted into a twisting motion that provides a basis for receptor activation.

  19. Involvement of AMPA/kainate and GABAA receptors in topiramate neuroprotective effects against methylphenidate abuse sequels involving oxidative stress and inflammation in rat isolated hippocampus.

    Science.gov (United States)

    Motaghinejad, Majid; Motevalian, Manijeh

    2016-08-01

    Abuses of methylphenidate (MPH) as psychostimulant cause neural damage of brain cells. Neuroprotective properties of topiramate (TPM) have been indicated in several studies but its exact mechanism of action remains unclear. The current study evaluates protective role of various doses of TPM and its mechanism of action in MPH induced oxidative stress and inflammation. The neuroprotective effects of various doses of TPM against MPH induced oxidative stress and inflammation were evaluated and then the action of TPM was studied in presence of domoic acid (DOM), as AMPA/kainate receptor agonist and bicuculline (BIC) as GABAA receptor antagonist, in isolated rat hippocampus. Open Field Test (OFT) was used to investigate motor activity changes. Oxidative, antioxidant and inflammatory factors were measured in isolated hippocampus. TPM (70 and 100mg/kg) decreased MPH induced motor activity disturbances and inhibit MPH induced oxidative stress and inflammation. On the other hand pretreatment of animals with DOM or BIC, inhibit this effect of TPM and potentiate MPH induced motor activity disturbances and increased lipid peroxidation, mitochondrial oxidized form of glutathione (GSSG) level, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in isolated hippocampal cells and decreased reduced form of glutathione (GSH) level, superoxide dismutase, glutathione peroxidase and glutathione reductase activity. It seems that TPM can protect cells of hippocampus from oxidative stress and neuroinflammation and it could be partly by activation of GABAA receptor and inhibition of AMPA/kainite receptor. PMID:27105819

  20. Involvement of AMPA/kainate and GABAA receptors in topiramate neuroprotective effects against methylphenidate abuse sequels involving oxidative stress and inflammation in rat isolated hippocampus.

    Science.gov (United States)

    Motaghinejad, Majid; Motevalian, Manijeh

    2016-08-01

    Abuses of methylphenidate (MPH) as psychostimulant cause neural damage of brain cells. Neuroprotective properties of topiramate (TPM) have been indicated in several studies but its exact mechanism of action remains unclear. The current study evaluates protective role of various doses of TPM and its mechanism of action in MPH induced oxidative stress and inflammation. The neuroprotective effects of various doses of TPM against MPH induced oxidative stress and inflammation were evaluated and then the action of TPM was studied in presence of domoic acid (DOM), as AMPA/kainate receptor agonist and bicuculline (BIC) as GABAA receptor antagonist, in isolated rat hippocampus. Open Field Test (OFT) was used to investigate motor activity changes. Oxidative, antioxidant and inflammatory factors were measured in isolated hippocampus. TPM (70 and 100mg/kg) decreased MPH induced motor activity disturbances and inhibit MPH induced oxidative stress and inflammation. On the other hand pretreatment of animals with DOM or BIC, inhibit this effect of TPM and potentiate MPH induced motor activity disturbances and increased lipid peroxidation, mitochondrial oxidized form of glutathione (GSSG) level, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in isolated hippocampal cells and decreased reduced form of glutathione (GSH) level, superoxide dismutase, glutathione peroxidase and glutathione reductase activity. It seems that TPM can protect cells of hippocampus from oxidative stress and neuroinflammation and it could be partly by activation of GABAA receptor and inhibition of AMPA/kainite receptor.

  1. Central nitric oxide modulates hindquarter vasodilation elicited by AMPA receptor stimulation in the NTS of conscious rats.

    Science.gov (United States)

    Dias, Ana Carolina Rodrigues; Colombari, Eduardo

    2006-05-01

    Microinjection of S-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) in the nucleus of the solitary tract (NTS) of conscious rats causes hypertension, bradycardia, and vasoconstriction in the renal, mesenteric, and hindquarter vascular beds. In the hindquarter, the initial vasoconstriction is followed by vasodilation with AMPA doses >5 pmol/100 nl. To test the hypothesis that this vasodilation is caused by activation of a nitroxidergic pathway in the NTS, we examined the effect of pretreatment with the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 10 nmol/100 nl, microinjected into the NTS) on changes in mean arterial pressure, heart rate, and regional vascular conductance (VC) induced by microinjection of AMPA (10 pmol/100 nl in the NTS) in conscious rats. AMPA increased hindquarter VC by 18 +/- 4%, but after pretreatment with L-NAME, AMPA reduced hindquarter VC by 16 +/- 7% and 17 +/- 9% (5 and 15 min after pretreatment, P NTS activates both vasodilatatory and vasoconstrictor mechanisms and that the vasodilatatory mechanism depends on production of nitric oxide in the NTS.

  2. Acute stress causes rapid synaptic insertion of Ca2+ -permeable AMPA receptors to facilitate long-term potentiation in the hippocampus.

    Science.gov (United States)

    Whitehead, Garry; Jo, Jihoon; Hogg, Ellen L; Piers, Thomas; Kim, Dong-Hyun; Seaton, Gillian; Seok, Heon; Bru-Mercier, Gilles; Son, Gi Hoon; Regan, Philip; Hildebrandt, Lars; Waite, Eleanor; Kim, Byeong-Chae; Kerrigan, Talitha L; Kim, Kyungjin; Whitcomb, Daniel J; Collingridge, Graham L; Lightman, Stafford L; Cho, Kwangwook

    2013-12-01

    The neuroendocrine response to episodes of acute stress is crucial for survival whereas the prolonged response to chronic stress can be detrimental. Learning and memory are particularly susceptible to stress with cognitive deficits being well characterized consequences of chronic stress. Although there is good evidence that acute stress can enhance cognitive performance, the mechanism(s) for this are unclear. We find that hippocampal slices, either prepared from rats following 30 min restraint stress or directly exposed to glucocorticoids, exhibit an N-methyl-d-aspartic acid receptor-independent form of long-term potentiation. We demonstrate that the mechanism involves an NMDA receptor and PKA-dependent insertion of Ca2+ -permeable AMPA receptors into synapses. These then trigger the additional NMDA receptor-independent form of LTP during high frequency stimulation.

  3. Efecto neuroprotector de los cannabinoides sobre la muerte neuronal inducida por Ampa en la médula espinal: Activación conjunta de los receptores CB1 y CB2

    Directory of Open Access Journals (Sweden)

    Carmen Guaza

    2005-03-01

    Full Text Available La sobreactivación de receptores de glutamato, como el receptor AMPA, induce la muerte neural por un proceso denominado excitotoxicidad, el cual ha sido claramente implicado en enfermedades agudas del sistema nerviso central (SNC, particularmente con daño axonal.

  4. Structural proof of a dimeric positive modulator bridging two identical AMPA receptor-binding sites

    DEFF Research Database (Denmark)

    Kaae, Birgitte Høiriis; Harpsøe, Kasper; Kastrup, Jette Sandholm Jensen;

    2007-01-01

    have dramatically increased potencies, more than three orders of magnitude higher than the corresponding monomers. Dimer (R,R)-2a was cocrystallized with the GluR2-S1S2J construct, and an X-ray crystallographic analysis showed (R,R)-2a to bridge two identical binding pockets on two neighboring GluR2...... subunits. Thus, this is biostructural evidence of a homomeric dimer bridging two identical receptor-binding sites....

  5. The antidepressant-like effects of glutamatergic drugs ketamine and AMPA receptor potentiator LY 451646 are preserved in bdnf⁺/⁻ heterozygous null mice.

    Science.gov (United States)

    Lindholm, Jesse S O; Autio, Henri; Vesa, Liisa; Antila, Hanna; Lindemann, Lothar; Hoener, Marius C; Skolnick, Phil; Rantamäki, Tomi; Castrén, Eero

    2012-01-01

    Accumulating evidence suggests that biogenic amine-based antidepressants act, at least in part, via regulation of brain-derived neurotrophic factor (BDNF) signaling. Biogenic amine-based antidepressants increase BDNF synthesis and activate its signaling pathway through TrkB receptors. Moreover, the antidepressant-like effects of these molecules are abolished in BDNF deficient mice. Glutamate-based drugs, including the NMDA antagonist ketamine, and the AMPA receptor potentiator LY 451646, mimic the effects of antidepressants in preclinical tests with high predictive validity. In humans, a single intravenous dose of ketamine produces an antidepressant effect that is rapid, robust and persistent. In this study, we examined the role of BDNF in expression of the antidepressant-like effects of ketamine and an AMPA receptor potentiator (LY 451646) in the forced swim test (FST). Ketamine and LY 451646 produced antidepressant-like effects in the FST in mice at 45 min after a single injection, but no effects were observed one week after a single ketamine injection. As previously reported, the effects of imipramine in the forced swim test were blunted in heterozygous BDNF knockout (bdnf(+/-)) mice. However ketamine and LY 451646 produced similar antidepressant-like responses in wildtype and bdnf(+/-) mice. Neither ketamine nor LY 451646 significantly influenced the levels BDNF or TrkB phosphorylation in the hippocampus when assessed at 45 min or 7 days after the drug administration. These data demonstrate that under the conditions tested, neither ketamine nor the AMPA-potentiator LY 451656 activate BDNF signaling, but produce a characteristic antidepressant-like response in heterozygous bdnf(+/-) mice. These data indicate that unlike biogenic amine-based agents, BDNF signaling does not play a pivotal role in the antidepressant effects of glutamate-based compounds. This article is part of a Special Issue entitled 'Anxiety and Depression'.

  6. The role of the prostaglandin D2 receptor, DP, in eosinophil trafficking

    DEFF Research Database (Denmark)

    Schratl, Petra; Royer, Julia F; Kostenis, Evi;

    2007-01-01

    of DP has remained unclear. We report in this study that, in addition to CRTH2, the DP receptor plays an important role in eosinophil trafficking. First, we investigated the release of eosinophils from bone marrow using the in situ perfused guinea pig hind limb preparation. PGD2 induced the rapid...... that eosinophils in human bone marrow specimens expressed DP and CRTH2 receptors at similar levels. Eosinophils isolated from human peripheral blood likewise expressed DP receptor protein but at lower levels than CRTH2. In agreement with this, the chemotaxis of human peripheral blood eosinophils was inhibited both...

  7. Ferlins: regulators of vesicle fusion for auditory neurotransmission, receptor trafficking and membrane repair.

    Science.gov (United States)

    Lek, Angela; Evesson, Frances J; Sutton, R Bryan; North, Kathryn N; Cooper, Sandra T

    2012-02-01

    Ferlins are a family of multiple C2 domain proteins with emerging roles in vesicle fusion and membrane trafficking. Ferlin mutations are associated with muscular dystrophy (dysferlin) and deafness (otoferlin) in humans, and infertility in Caenorhabditis elegans (Fer-1) and Drosophila (misfire), demonstrating their importance for normal cellular functioning. Ferlins show ancient origins in eukaryotic evolution and are detected in all eukaryotic kingdoms, including unicellular eukaryotes and apicomplexian protists, suggesting origins in a common ancestor predating eukaryotic evolutionary branching. The characteristic feature of the ferlin family is their multiple tandem cytosolic C2 domains (five to seven C2 domains), the most of any protein family, and an extremely rare feature amongst eukaryotic proteins. Ferlins also bear a unique nested DysF domain and small conserved 60-70 residue ferlin-specific sequences (Fer domains). Ferlins segregate into two subtypes based on the presence (type I ferlin) or absence (type II ferlin) of the DysF and FerA domains. Ferlins have diverse tissue-specific and developmental expression patterns, with ferlin animal models united by pathologies arising from defects in vesicle fusion. Consistent with their proposed role in vesicle trafficking, ferlin interaction partners include cytoskeletal motors, other vesicle-associated trafficking proteins and transmembrane receptors or channels. Herein we summarize the research history of the ferlins, an intriguing family of structurally conserved proteins with a preserved ancestral function as regulators of vesicle fusion and receptor trafficking.

  8. SYM 2206 (a potent non-competitive AMPA receptor antagonist) elevates the threshold for maximal electroshock-induced seizures in mice

    OpenAIRE

    Luszczki Jarogniew J.; Leszkowicz Magdalena; Kondrat-Wrobel Maria W.; Florek-Luszczki Magdalena

    2014-01-01

    The aim of this study was to determine the effect of SYM 2206 (a potent non-competitive AMPA receptor antagonist) on the threshold for maximal electroshock (MEST)-induced seizures in mice. Electroconvulsions were produced in mice by means of a current (sinewave, 50 Hz, maximum 500 V, strength from 4 to 14 mA, 0.2-s stimulus duration, tonic hind limb extension taken as the endpoint) delivered via ear-clip electrodes. SYM 2206 administered systemically (i.p.), 30 min before the MEST test, at do...

  9. 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...... neuronal activities of both enantiomers of IKM-159 prepared by enantioselective asymmetric synthesis. Employing (R)-2-amino-2-(4-methoxyphenyl)ethanol as a chiral auxiliary, (2R)-IKM-159 and the (2S)-counterpart were successfully synthesized in 0.70% and 1.5% yields, respectively, over total 18 steps. Both...

  10. Subthreshold receptive fields and baseline excitability of "silent" S1 callosal neurons in awake rabbits: contributions of AMPA/kainate and NMDA receptors.

    Science.gov (United States)

    Swadlow, H A; Hicks, T P

    1997-07-01

    The contribution of NMDA and non-NMDA receptors to excitatory subthreshold receptive fields was examined in callosal efferent neurons (CC neurons) in primary somatosensory cortex of the fully awake rabbit. Only neurons showing no traditional (suprathreshold) receptive fields were examined. Subthreshold responses were examined by monitoring the thresholds of efferent neurons to juxtasomal current pulses (JSCPs) delivered through the recording microelectrode. Changes in threshold following a peripheral conditioning stimulus signify a subthreshold response. Using this method, excitatory postsynaptic potentials and inhibitory postsynaptic potentials are manifested as decreases and increases in JSCP threshold, respectively. NMDA and non-NMDA agonists and antagonists were administered iontophoretically via a multibarrel micropipette assembly attached to the recording/stimulating microelectrode. Receptor-selective doses of both AMPA/kainate and NMDA antagonists decreased the excitability of CC neurons in the absence of any peripheral stimulation. Threshold to JSCPs rose by a mean of 20% for both classes of antagonist. Despite the similar effects of NMDA and non-NMDA antagonists on baseline excitability, these antagonists had dramatically different effects on the subthreshold excitatory response to activation of the receptive field. Whereas receptor-selective doses of AMPA/kainate antagonists either eliminated or severely attenuated the subthreshold excitatory responses to peripheral stimulation, NMDA antagonists had little or no effect on the subthreshold evoked response. PMID:9262195

  11. Activation of the sigma receptor 1 modulates AMPA receptor-mediated light-evoked excitatory postsynaptic currents in rat retinal ganglion cells.

    Science.gov (United States)

    Liu, Lei-Lei; Deng, Qin-Qin; Weng, Shi-Jun; Yang, Xiong-Li; Zhong, Yong-Mei

    2016-09-22

    Sigma receptor (σR), a unique receptor family, is classified into three subtypes: σR1, σR2 and σR3. It was previously shown that σR1 activation induced by 1μM SKF10047 (SKF) suppressed N-methyl-d-aspartate (NMDA) receptor-mediated responses of rat retinal ganglion cells (GCs) and the suppression was mediated by a distinct Ca(2+)-dependent phospholipase C (PLC)-protein kinase C (PKC) pathway. In the present work, using whole-cell patch-clamp techniques in rat retinal slice preparations, we further demonstrate that SKF of higher dosage (50μM) significantly suppressed AMPA receptor (AMPAR)-mediated light-evoked excitatory postsynaptic currents (L-EPSCs) of retinal ON-type GCs (ON GCs), and the effect was reversed by the σR1 antagonist BD1047, suggesting the involvement of σR1. The SKF (50μM) effect was unlikely due to a change in glutamate release from bipolar cells, as suggested by the unaltered paired-pulse ratio (PPR) of AMPAR-mediated EPSCs of ON GCs. SKF (50μM) did not change L-EPSCs of ON GCs when the G protein inhibitor GDP-β-S or the protein kinase G (PKG) inhibitor KT5823 was intracellularly infused. Calcium imaging further revealed that SKF (50μM) did not change intracellular calcium concentration in GCs and persisted to suppress L-EPSCs when intracellular calcium was chelated by BAPTA. The SKF (50μM) effect was intact when protein kinase A (PKA) and phosphatidylinostiol (PI)-PLC signaling pathways were both blocked. We conclude that the SKF (50μM) effect is Ca(2+)-independent, PKG-dependent, but not involving PKA, PI-PLC pathways. PMID:27373906

  12. Editing for an AMPA receptor subunit RNA in prefrontal cortex and striatum in Alzheimer's disease, Huntington's disease and schizophrenia

    Science.gov (United States)

    Akbarian, S.; Smith, M. A.; Jones, E. G.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    Animal studies and cell culture experiments demonstrated that posttranscriptional editing of the transcript of the GluR-2 gene, resulting in substitution of an arginine for glutamine in the second transmembrane region (TM II) of the expressed protein, is associated with a reduction in Ca2+ permeability of the receptor channel. Thus, disturbances in GluR-2 RNA editing with alteration of intracellular Ca2+ homeostasis could lead to neuronal dysfunction and even neuronal degeneration. The present study determined the proportions of edited and unedited GluR-2 RNA in the prefrontal cortex of brains from patients with Alzheimer's disease, in the striatum of brains from patients with Huntington's disease, and in the same areas of brains from age-matched schizophrenics and controls, by using reverse transcriptase-polymerase chain reaction, restriction endonuclease digestion, gel electrophoresis and scintillation radiometry. In the prefrontal cortex of controls, 99.9% were edited; in the prefrontal cortex both of schizophrenics and of Alzheimer's patients approximately 1.0% of all GluR-2 RNA molecules were unedited and 99% were edited. In the striatum of controls and of schizophrenics, approximately 0.5% of GluR-2 RNA molecules were unedited and 99.5% were edited; in the striatum of Huntington's patients nearly 5.0% of GluR-2 RNA was unedited. In the prefrontal white matter of controls, approximately 7.0% of GluR-2 RNA was unedited. In the normal human prefrontal cortex and striatum, the large majority of GluR-2 RNA molecules contains a CGG codon for arginine in the TMII coding region; this implies that the corresponding AMPA receptors have a low Ca2+ permeability, as previously demonstrated for the rat brain. The process of GluR-2 RNA editing is compromised in a region-specific manner in schizophrenia, in Alzheimer's disease and Huntington's Chorea although in each of these disorders there is still a large excess of edited GluR-2 RNA molecules. Disturbances of GluR-2 RNA

  13. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Identification of Phosphorylation Sites Regulating sst3 Somatostatin Receptor Trafficking.

    Science.gov (United States)

    Lehmann, Andreas; Kliewer, Andrea; Günther, Thomas; Nagel, Falko; Schulz, Stefan

    2016-06-01

    The human somatostatin receptor 3 (sst3) is expressed in about 50% of all neuroendocrine tumors and hence a promising target for multireceptor somatostatin analogs. The sst3 receptor is unique among ssts in that it exhibits a very long intracellular C-terminal tail containing a huge number of potential phosphate acceptor sites. Consequently, our knowledge about the functional role of the C-terminal tail in sst3 receptor regulation is very limited. Here, we have generated a series of phosphorylation-deficient mutants that enabled us to determine crucial sites for its agonist-induced β-arrestin mobilization, internalization, and down-regulation. Based on this information, we generated phosphosite-specific antibodies for C-terminal Ser(337)/Thr(341), Thr(348), and Ser(361) that enabled us to investigate the temporal patterns of sst3 phosphorylation and dephosphorylation. We found that the endogenous ligand somatostatin induced a rapid and robust phosphorylation that was completely blocked by the sst3 antagonist NVP-ACQ090. The stable somatostatin analogs pasireotide and octreotide promoted clearly less phosphorylation compared with somatostatin. We also show that sst3 phosphorylation occurred within seconds to minutes, whereas dephosphorylation of the sst3 receptor occurred at a considerable slower rate. In addition, we also identified G protein-coupled receptor kinases 2 and 3 and protein phosphatase 1α and 1β as key regulators of sst3 phosphorylation and dephosphorylation, respectively. Thus, we here define the C-terminal phosphorylation motif of the human sst3 receptor that regulates its agonist-promoted phosphorylation, β-arrestin recruitment, and internalization of this clinically relevant receptor.

  16. Involvement of hippocampal AMPA glutamate receptor changes and the cAMP/protein kinase A/CREB-P signalling pathway in memory consolidation of an avoidance task in rats

    Directory of Open Access Journals (Sweden)

    Bernabeu R.

    1997-01-01

    Full Text Available Training in step-down inhibitory avoidance (0.3-mA footshock is followed by biochemical changes in rat hippocampus that strongly suggest an involvement of quantitative changes in glutamate AMPA receptors, followed by changes in the dopamine D1 receptor/cAMP/protein kinase A (PKA/CREB-P signalling pathway in memory consolidation. AMPA binding to its receptor and levels of the AMPA receptor-specific subunit GluR1 increase in the hippocampus within the first 3 h after training (20-70%. Binding of the specific D1 receptor ligand, SCH23390, and cAMP levels increase within 3 or 6 h after training (30-100%. PKA activity and CREB-P levels show two peaks: a 35-40% increase 0 h after training, and a second increase 3-6 h later (35-60%. The results correlate with pharmacological findings showing an early post-training involvement of AMPA receptors, and a late involvement of the D1/cAMP/PKA/CREB-P pathway in memory consolidation of this task

  17. Membrane trafficking: licensing a cargo receptor for ER export.

    Science.gov (United States)

    Fromme, J Christopher

    2015-01-19

    Quality control in the endoplasmic reticulum prevents packaging of immature and misfolded proteins into vesicles, but the actual mechanisms involved in this process have not been defined for most cargos. A recent study demonstrates that the engagement of mature cargo with its receptor triggers the recruitment of a vesicle cargo adaptor. PMID:25602305

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

    Directory of Open Access Journals (Sweden)

    Brian J Wiltgen

    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.

  19. AMPA Receptor-mTOR Activation Is Required for the Antidepressant-like Effects of Sarcosine during the Forced Swim Test in rats: Insertion of AMPA Receptor may Play a Role

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    Kuang-Ti eChen

    2015-06-01

    Full Text Available Sarcosine, an endogenous amino acid, is a competitive inhibitor of the type I glycine transporter and an N-methyl-D-aspartate receptor (NMDAR coagonist. Recently, we found that sarcosine, an NMDAR enhancer, can improve depression-related behaviors in rodents and humans. This result differs from previous studies, which have reported antidepressant effects of NMDAR antagonists. The mechanisms underlying the therapeutic response of sarcosine remain unknown. This study examines the role of mammalian target of rapamycin (mTOR signaling and α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor (AMPAR activation, which are involved in the antidepressant-like effects of several glutamatergic system modulators. The effects of sarcosine in a forced swim test (FST and the expression levels of phosphorylated mTOR signaling proteins were examined in the absence or presence of mTOR and AMPAR inhibitors. In addition, the influence of sarcosine on AMPAR trafficking was determined by analyzing the phosphorylation of AMPAR subunit GluR1 at the PKA site (often considered an indicator for GluR1 membrane insertion in neurons. A single injection of sarcosine exhibited antidepressant-like effects in rats in the FST and rapidly activated the mTOR signaling pathway, which were significantly blocked by mTOR inhibitor rapamycin or the AMPAR inhibitor 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(fquinoxaline (NBQX pretreatment. Moreover, NBQX pretreatment eliminated the ability of sarcosine to stimulate the phosphorylated mTOR signaling proteins. Furthermore, GluR1 phosphorylation at its PKA site was significantly increased after an acute in vivo sarcosine treatment. The results demonstrated that sarcosine exerts antidepressant-like effects by enhancing AMPAR–mTOR signaling pathway activity and facilitating AMPAR membrane insertion.Highlights:- A single injection of sarcosine rapidly exerted antidepressant-like effects with a concomitant increase in the activation of the

  20. Desensitization, trafficking and resensitization of the pituitary thyrotropin-releasing hormone receptor

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    Patricia M Hinkle

    2012-12-01

    Full Text Available The pituitary receptor for thyrotropin-releasing hormone (TRH is a calcium-mobilizing G protein-coupled receptor (GPCR that signals through Gq/11, elevating calcium and activating protein kinase C. TRH receptor signaling is quickly desensitized as a consequence of receptor phosphorylation, arrestin binding and internalization. Following activation, TRH receptors are phosphorylated at multiple Ser/Thr residues in the cytoplasmic tail. Phosphorylation catalyzed by GPCR kinase 2 (GRK2 takes place rapidly, reaching a maximum within seconds. Arrestins bind to two phosphorylated regions, but only arrestin bound to the proximal region causes desensitization and internalization. Phosphorylation at Thr365 is critical for these responses. TRH receptors internalize in clathrin-coated vesicles with bound arrestin. Following endocytosis, vesicles containing phosphorylated TRH receptors soon merge with rab5-positive vesicles. Over approximately 20 minutes these form larger endosomes rich in rab4 and rab5, early sorting endosomes. After TRH is removed from the medium, dephosphorylated receptors start to accumulate in rab4-positive, rab5-negative recycling endosomes. The mechanisms responsible for sorting dephosphorylated receptors to recycling endosomes are unknown. TRH receptors from internal pools help repopulate the plasma membrane. Dephosphorylation of TRH receptors begins when TRH is removed from the medium regardless of receptor localization, although dephosphorylation is fastest when the receptor is on the plasma membrane. Protein phosphatase 1 is involved in dephosphorylation but the details of how the enzyme is targeted to the receptor remain obscure. It is likely that future studies will identify biased ligands for the TRH receptor, novel arrestin-dependent signaling pathways, mechanisms responsible for targeting kinases and phosphatases to the receptor, and principles governing receptor trafficking.

  1. Changes of AMPA receptor properties in the neocortex and hippocampus following pilocarpine-induced status epilepticus in rats.

    Science.gov (United States)

    Malkin, Sergey L; Amakhin, Dmitry V; Veniaminova, Ekaterina A; Kim, Kira Kh; Zubareva, Olga E; Magazanik, Lev G; Zaitsev, Aleksey V

    2016-07-01

    Temporal lobe epilepsy (TLE) is the most common type of epilepsy in humans. The lithium-pilocarpine model in rodents reproduces some of the main features of human TLE. Three-week-old Wistar rats were used in this study. The changes in AMPA receptor subunit composition were investigated in several brain areas, including the medial prefrontal cortex (mPFC), the temporal cortex (TC), and the dorsal (DH) and ventral hippocampus (VH) during the first week following pilocarpine-induced status epilepticus (PILO-induced SE). In the hippocampus, GluA1 and GluA2 mRNA expression slightly decreased after PILO-induced SE and returned to the initial level on the seventh day. We did not detect any significant changes in mRNA expression of the GluA1 and GluA2 subunits in the TC, whereas in the mPFC we observed a significant increase of GluA1 mRNA expression on the third day and a decrease in GluA2 mRNA expression during the entire first week. Accordingly, the GluA1/GluA2 expression ratio increased in the mPFC, and the functional properties of the pyramidal cell excitatory synapses were disturbed. Using whole-cell voltage-clamp recordings, we found that on the third day following PILO-induced SE, isolated mPFC pyramidal neurons showed an inwardly rectifying current-voltage relation of kainate-evoked currents, suggesting the presence of GluA2-lacking calcium-permeable AMPARs (CP-AMPARs). IEM-1460, a selective antagonist of CP-AMPARs, significantly reduced the amplitude of evoked EPSC in pyramidal neurons from mPFC slices on the first and third days, but not on the seventh day. The antagonist had no effects on EPSC amplitude in slices from control animals. Thus, our data demonstrate that PILO-induced SE affects subunit composition of AMPARs in different brain areas, including the mPFC. SE induces transient (up to few days) incorporation of CP-AMPARs in the excitatory synapses of mPFC pyramidal neurons, which may disrupt normal circuitry functions. PMID:27109923

  2. Drug Trafficking into Macrophages via the Endocytotic Receptor CD163

    Directory of Open Access Journals (Sweden)

    Jonas Heilskov Graversen

    2015-06-01

    Full Text Available In inflammatory diseases, macrophages are a main producer of a range of cytokines regulating the inflammatory state. This also includes inflammation induced by tumor growth, which recruits so-called tumor-associated macrophages supporting tumor growth. Macrophages are therefore relevant targets for cytotoxic or phenotype-modulating drugs in the treatment of inflammatory and cancerous diseases. Such targeting of macrophages has been tried using the natural propensity of macrophages to non-specifically phagocytose circulating foreign particulate material. In addition, the specific targeting of macrophage-expressed receptors has been used in order to obtain a selective uptake in macrophages and reduce adverse effects of off-target delivery of drugs. CD163 is a highly expressed macrophage-specific endocytic receptor that has been studied for intracellular delivery of small molecule drugs to macrophages using targeted liposomes or antibody drug conjugates. This review will focus on the biology of CD163 and its potential role as a target for selective macrophage targeting compared with other macrophage targeting approaches.

  3. Drug Trafficking into Macrophages via the Endocytotic Receptor CD163.

    Science.gov (United States)

    Graversen, Jonas Heilskov; Moestrup, Søren Kragh

    2015-01-01

    In inflammatory diseases, macrophages are a main producer of a range of cytokines regulating the inflammatory state. This also includes inflammation induced by tumor growth, which recruits so-called tumor-associated macrophages supporting tumor growth. Macrophages are therefore relevant targets for cytotoxic or phenotype-modulating drugs in the treatment of inflammatory and cancerous diseases. Such targeting of macrophages has been tried using the natural propensity of macrophages to non-specifically phagocytose circulating foreign particulate material. In addition, the specific targeting of macrophage-expressed receptors has been used in order to obtain a selective uptake in macrophages and reduce adverse effects of off-target delivery of drugs. CD163 is a highly expressed macrophage-specific endocytic receptor that has been studied for intracellular delivery of small molecule drugs to macrophages using targeted liposomes or antibody drug conjugates. This review will focus on the biology of CD163 and its potential role as a target for selective macrophage targeting compared with other macrophage targeting approaches. PMID:26111002

  4. Polarized trafficking of the sorting receptor SorLA in neurons and MDCK cells.

    Science.gov (United States)

    Klinger, Stine C; Højland, Anne; Jain, Shweta; Kjolby, Mads; Madsen, Peder; Svendsen, Anna Dorst; Olivecrona, Gunilla; Bonifacino, Juan S; Nielsen, Morten S

    2016-07-01

    The sorting receptor SorLA is highly expressed in neurons and is also found in other polarized cells. The receptor has been reported to participate in the trafficking of several ligands, some of which are linked to human diseases, including the amyloid precursor protein, TrkB, and Lipoprotein Lipase (LpL). Despite this, only the trafficking in nonpolarized cells has been described so far. Due to the many differences between polarized and nonpolarized cells, we examined the localization and trafficking of SorLA in epithelial Madin-Darby canine kidney (MDCK) cells and rat hippocampal neurons. We show that SorLA is mainly found in sorting endosomes and on the basolateral surface of MDCK cells and in the somatodendritic domain of neurons. This polarized distribution of SorLA respectively depends on an acidic cluster and an extended version of this cluster and involves the cellular adaptor complex AP-1. Furthermore, we show that SorLA can mediate transcytosis across a tight cell layer. PMID:27192064

  5. Intracellular Ca²⁺ and not the extracellular matrix determines surface dynamics of AMPA-type glutamate receptors on aspiny neurons.

    Science.gov (United States)

    Klueva, Julia; Gundelfinger, Eckart D; Frischknecht, R Renato; Heine, Martin

    2014-10-19

    The perisynaptic extracellular matrix (ECM) contributes to the control of the lateral mobility of AMPA-type glutamate receptors (AMPARs) at spine synapses of principal hippocampal neurons. Here, we have studied the effect of the ECM on the lateral mobility of AMPARs at shaft synapses of aspiny interneurons. Single particle tracking experiments revealed that the removal of the hyaluronan-based ECM with hyaluronidase does not affect lateral receptor mobility on the timescale of seconds. Similarly, cross-linking with specific antibodies against the extracellular domain of the GluA1 receptor subunit, which affects lateral receptor mobility on spiny neurons, does not influence receptor mobility on aspiny neurons. AMPARs on aspiny interneurons are characterized by strong inward rectification indicating a significant fraction of Ca(2+)-permeable receptors. Therefore, we tested whether Ca(2+) controls AMPAR mobility in these neurons. Application of the membrane-permeable Ca(2+) chelator BAPTA-AM significantly increased the lateral mobility of GluA1-containing synaptic and extrasynaptic receptors. These data indicate that the perisynaptic ECM affects the lateral mobility differently on spiny and aspiny neurons. Although ECM structures on interneurons appear much more prominent, their influence on AMPAR mobility seems to be negligible at short timescales. PMID:25225098

  6. Modulation of cell surface GABA B receptors by desensitization,trafficking and regulated degradation

    Institute of Scientific and Technical Information of China (English)

    Dietmar; Benke; Khaled; Zemoura; Patrick; J; Maier

    2012-01-01

    Inhibitory neurotransmission ensures normal brain function by counteracting and integrating excitatory activity.-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the mammalian central nervous system,and mediates its effects via two classes of receptors:the GABA A and GABA B receptors.GABA A receptors are heteropentameric GABA-gated chloride channels and responsible for fast inhibitory neurotransmission.GABA B receptors are heterodimeric G protein coupled receptors (GPCR) that mediate slow and prolonged inhibitory transmission.The extent of inhibitory neurotransmission is determined by a variety of factors,such as the degree of transmitter release and changes in receptor activity by posttranslational modifications (e.g.,phosphorylation),as well as by the number of receptors present in the plasma membrane available for signal transduction.The level of GABA B receptors at the cell surface critically depends on the residence time at the cell surface and finally the rates of endocytosis and degradation.In this review we focus primarily on recent advances in the understanding of trafficking mechanisms that determine the expression level of GABA B receptors in the plasma membrane,and thereby signaling strength.

  7. 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…

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

    DEFF Research Database (Denmark)

    Jensen, J B; Lund, Trine Meldgaard; Timmermann, D 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...

  9. AMPA Receptor-mTOR Activation is Required for the Antidepressant-Like Effects of Sarcosine during the Forced Swim Test in Rats: Insertion of AMPA Receptor may Play a Role.

    Science.gov (United States)

    Chen, Kuang-Ti; Tsai, Mang-Hung; Wu, Ching-Hsiang; Jou, Ming-Jia; Wei, I-Hua; Huang, Chih-Chia

    2015-01-01

    Sarcosine, an endogenous amino acid, is a competitive inhibitor of the type I glycine transporter and an N-methyl-d-aspartate receptor (NMDAR) coagonist. Recently, we found that sarcosine, an NMDAR enhancer, can improve depression-related behaviors in rodents and humans. This result differs from previous studies, which have reported antidepressant effects of NMDAR antagonists. The mechanisms underlying the therapeutic response of sarcosine remain unknown. This study examines the role of mammalian target of rapamycin (mTOR) signaling and α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor (AMPAR) activation, which are involved in the antidepressant-like effects of several glutamatergic system modulators. The effects of sarcosine in a forced swim test (FST) and the expression levels of phosphorylated mTOR signaling proteins were examined in the absence or presence of mTOR and AMPAR inhibitors. In addition, the influence of sarcosine on AMPAR trafficking was determined by analyzing the phosphorylation of AMPAR subunit GluR1 at the PKA site (often considered an indicator for GluR1 membrane insertion in neurons). A single injection of sarcosine exhibited antidepressant-like effects in rats in the FST and rapidly activated the mTOR signaling pathway, which were significantly blocked by mTOR inhibitor rapamycin or the AMPAR inhibitor 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (NBQX) pretreatment. Moreover, NBQX pretreatment eliminated the ability of sarcosine to stimulate the phosphorylated mTOR signaling proteins. Furthermore, GluR1 phosphorylation at its PKA site was significantly increased after an acute in vivo sarcosine treatment. The results demonstrated that sarcosine exerts antidepressant-like effects by enhancing AMPAR-mTOR signaling pathway activity and facilitating AMPAR membrane insertion. Highlights-A single injection of sarcosine rapidly exerted antidepressant-like effects with a concomitant increase in the activation of the mammalian

  10. The binding of NCAM to FGFR1 induces a specific cellular response mediated by receptor trafficking

    DEFF Research Database (Denmark)

    Francavilla, Chiara; Cattaneo, Paola; Berezin, Vladimir;

    2009-01-01

    different from that elicited by FGF-2. In contrast to FGF-induced degradation of endocytic FGFR1, NCAM promotes the stabilization of the receptor, which is recycled to the cell surface in a Rab11- and Src-dependent manner. In turn, FGFR1 recycling is required for NCAM-induced sustained activation of various...... effectors. Furthermore, NCAM, but not FGF-2, promotes cell migration, and this response depends on FGFR1 recycling and sustained Src activation. Our results implicate NCAM as a nonconventional ligand for FGFR1 that exerts a peculiar control on the intracellular trafficking of the receptor, resulting...... in a specific cellular response. Besides introducing a further level of complexity in the regulation of FGFR1 function, our findings highlight the link of FGFR recycling with sustained signaling and cell migration and the critical role of these events in dictating the cellular response evoked by receptor...

  11. In silico investigation of ADAM12 effect on TGF-β receptors trafficking

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    LeMeur Nolwenn

    2009-09-01

    Full Text Available Abstract Background The transforming growth factor beta is known to have pleiotropic effects, including differentiation, proliferation and apoptosis. However the underlying mechanisms remain poorly understood. The regulation and effect of TGF-β signaling is complex and highly depends on specific protein context. In liver, we have recently showed that the disintegrin and metalloproteinase ADAM12 interacts with TGF-β receptors and modulates their trafficking among membranes, a crucial point in TGF-β signaling and development of fibrosis. The present study aims to better understand how ADAM12 impacts on TGF-β receptors trafficking and TGF-β signaling. Findings We extracted qualitative biological observations from experimental data and defined a family of models producing a behavior compatible with the presence of ADAM12. We computationally explored the properties of this family of models which allowed us to make novel predictions. We predict that ADAM12 increases TGF-β receptors internalization rate between the cell surface and the endosomal membrane. It also appears that ADAM12 modifies TGF-β signaling shape favoring a permanent response by removing the transient component observed under physiological conditions. Conclusion In this work, confronting differential models with qualitative biological observations, we obtained predictions giving new insights into the role of ADAM12 in TGF-β signaling and hepatic fibrosis process.

  12. Vacuolar Sorting Receptor-Mediated Trafficking of Soluble Vacuolar Proteins in Plant Cells

    Directory of Open Access Journals (Sweden)

    Hyangju Kang

    2014-08-01

    Full Text Available Vacuoles are one of the most prominent organelles in plant cells, and they play various important roles, such as degradation of waste materials, storage of ions and metabolites, and maintaining turgor. During the past two decades, numerous advances have been made in understanding how proteins are specifically delivered to the vacuole. One of the most crucial steps in this process is specific sorting of soluble vacuolar proteins. Vacuolar sorting receptors (VSRs, which are type I membrane proteins, are involved in the sorting and packaging of soluble vacuolar proteins into transport vesicles with the help of various accessory proteins. To date, large amounts of data have led to the development of two different models describing VSR-mediated vacuolar trafficking that are radically different in multiple ways, particularly regarding the location of cargo binding to, and release from, the VSR and the types of carriers utilized. In this review, we summarize current literature aimed at elucidating VSR-mediated vacuolar trafficking and compare the two models with respect to the sorting signals of vacuolar proteins, as well as the molecular machinery involved in VSR-mediated vacuolar trafficking and its action mechanisms.

  13. Fscn1 is required for the trafficking of TGF-β family type I receptors during endoderm formation

    Science.gov (United States)

    Liu, Zhaoting; Ning, Guozhu; Xu, Ranran; Cao, Yu; Meng, Anming; Wang, Qiang

    2016-01-01

    Microtubules function in TGF-β signalling by facilitating the cytoplasmic trafficking of internalized receptors and the nucleocytoplasmic shuttling of Smads. However, nothing is known about whether actin filaments are required for these processes. Here we report that zebrafish actin-bundling protein fscn1a is highly expressed in mesendodermal precursors and its expression is directly regulated by the TGF-β superfamily member Nodal. Knockdown or knockout of fscn1a leads to a reduction of Nodal signal transduction and endoderm formation in zebrafish embryos. Fscn1 specifically interacts with TGF-β family type I receptors, and its depletion disrupts the association between receptors and actin filaments and sequesters the internalized receptors into clathrin-coated vesicles. Therefore, Fscn1 acts as a molecular linker between TGF-β family type I receptors and the actin filaments to promote the trafficking of internalized receptors from clathrin-coated vesicles to early endosomes during zebrafish endoderm formation. PMID:27545838

  14. Distinct human and mouse membrane trafficking systems for sweet taste receptors T1r2 and T1r3.

    Science.gov (United States)

    Shimizu, Madoka; Goto, Masao; Kawai, Takayuki; Yamashita, Atsuko; Kusakabe, Yuko

    2014-01-01

    The sweet taste receptors T1r2 and T1r3 are included in the T1r taste receptor family that belongs to class C of the G protein-coupled receptors. Heterodimerization of T1r2 and T1r3 is required for the perception of sweet substances, but little is known about the mechanisms underlying this heterodimerization, including membrane trafficking. We developed tagged mouse T1r2 and T1r3, and human T1R2 and T1R3 and evaluated membrane trafficking in human embryonic kidney 293 (HEK293) cells. We found that human T1R3 surface expression was only observed when human T1R3 was coexpressed with human T1R2, whereas mouse T1r3 was expressed without mouse T1r2 expression. A domain-swapped chimera and truncated human T1R3 mutant showed that the Venus flytrap module and cysteine-rich domain (CRD) of human T1R3 contain a region related to the inhibition of human T1R3 membrane trafficking and coordinated regulation of human T1R3 membrane trafficking. We also found that the Venus flytrap module of both human T1R2 and T1R3 are needed for membrane trafficking, suggesting that the coexpression of human T1R2 and T1R3 is required for this event. These results suggest that the Venus flytrap module and CRD receive taste substances and play roles in membrane trafficking of human T1R2 and T1R3. These features are different from those of mouse receptors, indicating that human T1R2 and T1R3 are likely to have a novel membrane trafficking system.

  15. Effects of ketamine-midazolam anesthesia on the expression of NMDA and AMPA receptor subunit in the peri-infarction of rat brain

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yue-lin; ZHANG Peng-bo; QIU Shu-dong; LIU Yong; TIAN Ying-fang; WANG Ying

    2006-01-01

    Background Activation of N-methyl-D-aspartate (NMDA) receptors and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors play an important role in the neurons death induced by ischemia.The mitigating effect of intravenous anesthetics on ischemic neuron injury is related to their influence on NMDA receptors. This study was performed to investigate the effect of ketamine-midazolam anesthesia on the NMDA and AMPA receptor subunits expression in the peri-infarction of ischemic rat brain and explore its potential mechanism of neuroprotection.This study was supported by National Natural Science Foundation of China (NSFC) (No.30200291).Methods Thirty Sprague Dawley (SD) rats were subjected to permanent middle cerebral artery occlusion under ketamine/atropine (100/0.05 mg/kg) or ketamine-midazolam/atropine (60/50/0.05 mg/kg) intraperitoneal anesthesia (n=15 each). Twenty-four hours after ischemia, five rats in each group were killed by injecting the above dosage of ketamine or ketamine-midazolam intraperitoneally and infarct size was measured. Twenty-four and 72 hours after ischemia, four rats in each group were killed by injecting the above dosage of ketamine or ketamine-midazolam intraperitoneally. After staining the brain tissue slices with toluidine blue, the survived neurons in the peri-infarction were observed. Also, the expression level of NMDA receptors 1 (NR1), NMDA receptors 2A (NR2A), NMDA receptors 2B (NR2B) and AMPA (GluR1 subunit) were determined by grayscale analysis in immunohistochemical stained slices.Results Compared with ketamine anesthesia, ketamine-midazolam anesthesia produced not only smaller infarct size [(24.1±4.6)% vs (38.4±4.2)%, P<0.05], but also higher neuron density (24 hours: 846± 16 vs 756±24,P<0.05; 72 hours: 882±22 vs 785± 18, P<0.05) and lower NR2A (24 hours: 123.0±4.9 vs 95.0±2.5, P<0.05; 72 hours: 77.8±4.1 vs 54.2±3.9, P<0.05) and NR2B (24 hours: 98.5±2.7 vs 76.3±2.4, P<0.05; 72hours: 67.2

  16. IRAS Modulates Opioid Tolerance and Dependence by Regulating μ Opioid Receptor Trafficking.

    Science.gov (United States)

    Li, Fei; Ma, Hao; Wu, Ning; Li, Jin

    2016-09-01

    Imidazoline receptor antisera-selected (IRAS) protein, the mouse homologue named Nischarin, was found to target to early endosomes with properties of sorting nexins in vitro. Recently, we generated IRAS knockout mice and found IRAS deficiency exacerbated the analgesic tolerance and physical dependence caused by opioids, suggesting that IRAS plays a role in regulating μ opioid receptor (MOR) functions. In the present study, we found that IRAS interacts with MOR and regulates MOR trafficking in vitro. In the CHO or HEK293 cells co-expressing MOR and IRAS, IRAS, through its PX domain, interacted with MOR. The interaction facilitated the recycling of internalized MOR and prevented MOR downregulation induced by DAMGO, the MOR agonist. Functionally, IRAS accelerated MOR resensitization and attenuated DAMGO-induced MOR desensitization, which is believed as one of mechanisms mediating opioid tolerance and dependence. Taken together, we propose that IRAS is a new MOR interacting protein and regulates agonist-induced trafficking of MOR via sorting internalized MOR to the recycling pathway, which may be a molecular mechanism underlying IRAS modulating opioid tolerance and dependence. PMID:26363797

  17. Mutations of Vasopressin Receptor 2 Including Novel L312S Have Differential Effects on Trafficking.

    Science.gov (United States)

    Tiulpakov, Anatoly; White, Carl W; Abhayawardana, Rekhati S; See, Heng B; Chan, Audrey S; Seeber, Ruth M; Heng, Julian I; Dedov, Ivan; Pavlos, Nathan J; Pfleger, Kevin D G

    2016-08-01

    Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a genetic disease first described in 2 unrelated male infants with severe symptomatic hyponatremia. Despite undetectable arginine vasopressin levels, patients have inappropriately concentrated urine resulting in hyponatremia, hypoosmolality, and natriuresis. Here, we describe and functionally characterize a novel vasopressin type 2 receptor (V2R) gain-of-function mutation. An L312S substitution in the seventh transmembrane domain was identified in a boy presenting with water-induced hyponatremic seizures at the age of 5.8 years. We show that, compared with wild-type V2R, the L312S mutation results in the constitutive production of cAMP, indicative of the gain-of-function NSIAD profile. Interestingly, like the previously described F229V and I130N NSIAD-causing mutants, this appears to both occur in the absence of notable constitutive β-arrestin2 recruitment and can be reduced by the inverse agonist Tolvaptan. In addition, to understand the effect of various V2R substitutions on the full receptor "life-cycle," we have used and further developed a bioluminescence resonance energy transfer intracellular localization assay using multiple localization markers validated with confocal microscopy. This allowed us to characterize differences in the constitutive and ligand-induced localization and trafficking profiles of the novel L312S mutation as well as for previously described V2R gain-of-function mutants (NSIAD; R137C and R137L), loss-of-function mutants (nephrogenic diabetes insipidus; R137H, R181C, and M311V), and a putative silent V266A V2R polymorphism. In doing so, we describe differences in trafficking between unique V2R substitutions, even at the same amino acid position, therefore highlighting the value of full and thorough characterization of receptor function beyond simple signaling pathway analysis. PMID:27355191

  18. Trafficking of epidermal growth factor receptor ligands in polarized epithelial cells.

    Science.gov (United States)

    Singh, Bhuminder; Coffey, Robert J

    2014-01-01

    A largely unilamellar epithelial layer lines body cavities and organ ducts such as the digestive tract and kidney tubules. This polarized epithelium is composed of biochemically and functionally separate apical and basolateral surfaces. The epidermal growth factor receptor (EGFR) signaling pathway is a critical regulator of epithelial homeostasis and is perturbed in a number of epithelial disorders. It is underappreciated that in vivo EGFR signaling is most often initiated by cell-surface delivery and processing of one of seven transmembrane ligands, resulting in release of the soluble form that binds EGFR. In polarized epithelial cells, EGFR is restricted largely to the basolateral surface, and apical or basolateral ligand delivery therefore has important biological consequences. In vitro approaches have been used to study the biosynthesis, cell-surface delivery, proteolytic processing, and release of soluble EGFR ligands in polarized epithelial cells. We review these results, discuss their relevance to normal physiology, and demonstrate the pathophysiological consequences of aberrant trafficking. These studies have uncovered a rich diversity of apico-basolateral trafficking mechanisms among the EGFR ligands, provided insights into the pathogenesis of an inherited magnesium-wasting disorder of the kidney (isolated renal hypomagnesemia), and identified a new mode of EGFR ligand signaling via exosomes. PMID:24215440

  19. Monitoring G protein-coupled receptor and β-arrestin trafficking in live cells using enhanced bystander BRET

    Science.gov (United States)

    Namkung, Yoon; Le Gouill, Christian; Lukashova, Viktoria; Kobayashi, Hiroyuki; Hogue, Mireille; Khoury, Etienne; Song, Mideum; Bouvier, Michel; Laporte, Stéphane A.

    2016-01-01

    Endocytosis and intracellular trafficking of receptors are pivotal to maintain physiological functions and drug action; however, robust quantitative approaches are lacking to study such processes in live cells. Here we present new bioluminescence resonance energy transfer (BRET) sensors to quantitatively monitor G protein-coupled receptors (GPCRs) and β-arrestin trafficking. These sensors are based on bystander BRET and use the naturally interacting chromophores luciferase (RLuc) and green fluorescent protein (rGFP) from Renilla. The versatility and robustness of this approach are exemplified by anchoring rGFP at the plasma membrane or in endosomes to generate high dynamic spectrometric BRET signals on ligand-promoted recruitment or sequestration of RLuc-tagged proteins to, or from, specific cell compartments, as well as sensitive subcellular BRET imaging for protein translocation visualization. These sensors are scalable to high-throughput formats and allow quantitative pharmacological studies of GPCR trafficking in real time, in live cells, revealing ligand-dependent biased trafficking of receptor/β-arrestin complexes. PMID:27397672

  20. Monitoring G protein-coupled receptor and β-arrestin trafficking in live cells using enhanced bystander BRET.

    Science.gov (United States)

    Namkung, Yoon; Le Gouill, Christian; Lukashova, Viktoria; Kobayashi, Hiroyuki; Hogue, Mireille; Khoury, Etienne; Song, Mideum; Bouvier, Michel; Laporte, Stéphane A

    2016-01-01

    Endocytosis and intracellular trafficking of receptors are pivotal to maintain physiological functions and drug action; however, robust quantitative approaches are lacking to study such processes in live cells. Here we present new bioluminescence resonance energy transfer (BRET) sensors to quantitatively monitor G protein-coupled receptors (GPCRs) and β-arrestin trafficking. These sensors are based on bystander BRET and use the naturally interacting chromophores luciferase (RLuc) and green fluorescent protein (rGFP) from Renilla. The versatility and robustness of this approach are exemplified by anchoring rGFP at the plasma membrane or in endosomes to generate high dynamic spectrometric BRET signals on ligand-promoted recruitment or sequestration of RLuc-tagged proteins to, or from, specific cell compartments, as well as sensitive subcellular BRET imaging for protein translocation visualization. These sensors are scalable to high-throughput formats and allow quantitative pharmacological studies of GPCR trafficking in real time, in live cells, revealing ligand-dependent biased trafficking of receptor/β-arrestin complexes. PMID:27397672

  1. Autoimmune epilepsy: distinct subpopulations of epilepsy patients harbor serum autoantibodies to either glutamate/AMPA receptor GluR3, glutamate/NMDA receptor subunit NR2A or double-stranded DNA.

    Science.gov (United States)

    Ganor, Yonatan; Goldberg-Stern, Hadassa; Lerman-Sagie, Tally; Teichberg, Vivian I; Levite, Mia

    2005-06-01

    We studied 82 patients with different types of epilepsy and 49 neurologically intact non-epileptic controls, and identified three different subpopulations of epilepsy patients bearing significantly elevated levels of autoantibodies to either GluR3B-peptide of glutamate/AMPA receptor subtype 3 (17/82; 21% of patients), or to a peptide of NR2A subunit of glutamate/NMDA receptors (15/82; 18%), or to double-stranded (ds) DNA, the hallmark of systemic lupus erythematosus (13/80; 16%). Most patients had only one antibody type, arguing against cross-reactivity. Nearly all anti-dsDNA Ab-positive patients did not harbor anti-nuclear autoantibodies. Most patients had no history of brain damage, febrile convulsions, early onset epilepsy, acute epilepsy or intractable seizures. We suggest to measure the 'autoimmune-fingerprints' of epilepsy patients for diagnostic and therapeutic purposes. PMID:15978777

  2. Association of nonsense mutation in GABRG2 with abnormal trafficking of GABAA receptors in severe epilepsy.

    Science.gov (United States)

    Ishii, Atsushi; Kanaumi, Takeshi; Sohda, Miwa; Misumi, Yoshio; Zhang, Bo; Kakinuma, Naoto; Haga, Yoshiko; Watanabe, Kazuyoshi; Takeda, Sen; Okada, Motohiro; Ueno, Shinya; Kaneko, Sunao; Takashima, Sachio; Hirose, Shinichi

    2014-03-01

    Mutations in GABRG2, which encodes the γ2 subunit of GABAA receptors, can cause both genetic epilepsy with febrile seizures plus (GEFS+) and Dravet syndrome. Most GABRG2 truncating mutations associated with Dravet syndrome result in premature termination codons (PTCs) and are stably translated into mutant proteins with potential dominant-negative effects. This study involved search for mutations in candidate genes for Dravet syndrome, namely SCN1A, 2A, 1B, 2B, GABRA1, B2, and G2. A heterozygous nonsense mutation (c.118C>T, p.Q40X) in GABRG2 was identified in dizygotic twin girls with Dravet syndrome and their apparently healthy father. Electrophysiological studies with the reconstituted GABAA receptors in HEK cells showed reduced GABA-induced currents when mutated γ2 DNA was cotransfected with wild-type α1 and β2 subunits. In this case, immunohistochemistry using antibodies to the α1 and γ2 subunits of GABAA receptor showed granular staining in the soma. In addition, microinjection of mutated γ2 subunit cDNA into HEK cells severely inhibited intracellular trafficking of GABAA receptor subunits α1 and β2, and retention of these proteins in the endoplasmic reticulum. The mutated γ2 subunit-expressing neurons also showed impaired axonal transport of the α1 and β2 subunits. Our findings suggested that different phenotypes of epilepsy, e.g., GEFS+ and Dravet syndrome (which share similar abnormalities in causative genes) are likely due to impaired axonal transport associated with the dominant-negative effects of GABRG2. PMID:24480790

  3. SYM 2206 (a potent non-competitive AMPA receptor antagonist elevates the threshold for maximal electroshock-induced seizures in mice

    Directory of Open Access Journals (Sweden)

    Luszczki Jarogniew J.

    2014-06-01

    Full Text Available The aim of this study was to determine the effect of SYM 2206 (a potent non-competitive AMPA receptor antagonist on the threshold for maximal electroshock (MEST-induced seizures in mice. Electroconvulsions were produced in mice by means of a current (sinewave, 50 Hz, maximum 500 V, strength from 4 to 14 mA, 0.2-s stimulus duration, tonic hind limb extension taken as the endpoint delivered via ear-clip electrodes. SYM 2206 administered systemically (i.p., 30 min before the MEST test, at doses of 2.5 and 5 mg/kg, did not alter the threshold for maximal electroconvulsions in mice. In contrast, SYM 2206 at doses of 10 and 20 mg/kg significantly elevated the threshold for maximal electroconvulsions in mice (P<0.01 and P<0.001. Linear regression analysis of SYM 2206 doses and their corresponding threshold increases allowed for the determination of threshold increasing doses by 20% and 50% (TID20 and TID50 values that elevate the threshold in drug-treated animals over the threshold in control animals. The experimentally derived TID20 and TID50 values for SYM 2206 were 4.25 and 10.56 mg/kg, respectively. SYM 2206 dose-dependently increased the threshold for MEST-induced seizures, suggesting the anticonvulsant action of the compound in this seizure model in mice.

  4. Cellular Recognition and Trafficking of Amorphous Silica Nanoparticles by Macrophage Scavenger Receptor A

    Energy Technology Data Exchange (ETDEWEB)

    Orr, Galya; Chrisler, William B.; Cassens, Kaylyn J.; Tan, Ruimin; Tarasevich, Barbara J.; Markillie, Lye Meng; Zangar, Richard C.; Thrall, Brian D.

    2011-09-01

    The internalization of engineered nanoparticles (ENPs) into cells is known to involve active transport mechanisms, yet the precise biological molecules involved are poorly understood. We demonstrate that the uptake of amorphous silica ENPs (92 nm) by macrophage cells is strongly inhibited by silencing expression of scavenger receptor A (SR-A). In addition, ENP uptake is augmented by introducing SR-A expression into human cells that are normally non-phagocytic. Confocal fluorescent microscopy analyses show that the majority of single or small clusters of silica ENPs co-localize intracellularly with SR-A and are internalized through a pathway characteristic of clathrin-dependent endocytosis. In contrast, larger silica NP agglomerates (>500 nm) are poorly co-localized with the receptor, suggesting independent trafficking or internalization pathways are involved. SR-A silencing also caused decreased cellular secretion of pro-inflammatory cytokines in response to silica ENPs. As SR-A is expressed in macrophages throughout the reticulo-endothelial system, this pathway is likely an important determinant of the biodistribution of, and cellular response to ENPs.

  5. Ca(2+ permeable AMPA receptor induced long-term potentiation requires PI3/MAP kinases but not Ca/CaM-dependent kinase II.

    Directory of Open Access Journals (Sweden)

    Suhail Asrar

    Full Text Available Ca(2+ influx via GluR2-lacking Ca(2+-permeable AMPA glutamate receptors (CP-AMPARs can trigger changes in synaptic efficacy in both interneurons and principle neurons, but the underlying mechanisms remain unknown. We took advantage of genetically altered mice with no or reduced GluR2, thus allowing the expression of synaptic CP-AMPARs, to investigate the molecular signaling process during CP-AMPAR-induced synaptic plasticity at CA1 synapses in the hippocampus. Utilizing electrophysiological techniques, we demonstrated that these receptors were capable of inducing numerous forms of long-term potentiation (referred to as CP-AMPAR dependent LTP through a number of different induction protocols, including high-frequency stimulation (HFS and theta-burst stimulation (TBS. This included a previously undemonstrated form of protein-synthesis dependent late-LTP (L-LTP at CA1 synapses that is NMDA-receptor independent. This form of plasticity was completely blocked by the selective CP-AMPAR inhibitor IEM-1460, and found to be dependent on postsynaptic Ca(2+ ions through calcium chelator (BAPTA studies. Surprisingly, Ca/CaM-dependent kinase II (CaMKII, the key protein kinase that is indispensable for NMDA-receptor dependent LTP at CA1 synapses appeared to be not required for the induction of CP-AMPAR dependent LTP due to the lack of effect of two separate pharmacological inhibitors (KN-62 and staurosporine on this form of potentiation. Both KN-62 and staurosporine strongly inhibited NMDA-receptor dependent LTP in control studies. In contrast, inhibitors for PI3-kinase (LY294002 and wortmannin or the MAPK cascade (PD98059 and U0126 significantly attenuated this CP-AMPAR-dependent LTP. Similarly, postsynaptic infusion of tetanus toxin (TeTx light chain, an inhibitor of exocytosis, also had a significant inhibitory effect on this form of LTP. These results suggest that distinct synaptic signaling underlies GluR2-lacking CP-AMPAR-dependent LTP, and reinforces

  6. Cortical kindling induces elevated levels of AMPA and GABA receptor subunit mRNA within the amygdala/piriform region and is associated with behavioral changes in the rat.

    Science.gov (United States)

    Henderson, Amy K; Galic, Michael A; Teskey, G Campbell

    2009-11-01

    Cortical kindling causes alterations within the motor cortex and results in long-standing motor deficits. Less attention has been directed to other regions that also participate in the epileptiform activity. We examined if cortical kindling could induce changes in excitatory and inhibitory receptor subunit mRNA in the amygdala/piriform regions and if such changes are associated with behavioral deficits. After cortical kindling, amygdala/piriform regions were dissected to analyze mRNA levels of NMDA, AMPA, and GABA receptor subunits using reverse transcription polymerase chain reaction, or rats were subjected to a series of behavioral tests. Kindled rats had significantly greater amounts of GluR1 and GluR2 AMPA receptor mRNA, and alpha1 and alpha2 GABA receptor subunit mRNA, compared with sham controls, which was associated with greater anxiety-like behaviors in the elevated plus maze and reduced freezing behaviors in the fear conditioning task. In summary, cortical kindling produces dynamic receptor subunit changes in regions in addition to the seizure focus.

  7. One-way membrane trafficking of SOS in receptor-triggered Ras activation.

    Science.gov (United States)

    Christensen, Sune M; Tu, Hsiung-Lin; Jun, Jesse E; Alvarez, Steven; Triplet, Meredith G; Iwig, Jeffrey S; Yadav, Kamlesh K; Bar-Sagi, Dafna; Roose, Jeroen P; Groves, Jay T

    2016-09-01

    SOS is a key activator of the small GTPase Ras. In cells, SOS-Ras signaling is thought to be initiated predominantly by membrane recruitment of SOS via the adaptor Grb2 and balanced by rapidly reversible Grb2-SOS binding kinetics. However, SOS has multiple protein and lipid interactions that provide linkage to the membrane. In reconstituted-membrane experiments, these Grb2-independent interactions were sufficient to retain human SOS on the membrane for many minutes, during which a single SOS molecule could processively activate thousands of Ras molecules. These observations raised questions concerning how receptors maintain control of SOS in cells and how membrane-recruited SOS is ultimately released. We addressed these questions in quantitative assays of reconstituted SOS-deficient chicken B-cell signaling systems combined with single-molecule measurements in supported membranes. These studies revealed an essentially one-way trafficking process in which membrane-recruited SOS remains trapped on the membrane and continuously activates Ras until being actively removed via endocytosis. PMID:27501536

  8. One-way membrane trafficking of SOS in receptor-triggered Ras activation.

    Science.gov (United States)

    Christensen, Sune M; Tu, Hsiung-Lin; Jun, Jesse E; Alvarez, Steven; Triplet, Meredith G; Iwig, Jeffrey S; Yadav, Kamlesh K; Bar-Sagi, Dafna; Roose, Jeroen P; Groves, Jay T

    2016-09-01

    SOS is a key activator of the small GTPase Ras. In cells, SOS-Ras signaling is thought to be initiated predominantly by membrane recruitment of SOS via the adaptor Grb2 and balanced by rapidly reversible Grb2-SOS binding kinetics. However, SOS has multiple protein and lipid interactions that provide linkage to the membrane. In reconstituted-membrane experiments, these Grb2-independent interactions were sufficient to retain human SOS on the membrane for many minutes, during which a single SOS molecule could processively activate thousands of Ras molecules. These observations raised questions concerning how receptors maintain control of SOS in cells and how membrane-recruited SOS is ultimately released. We addressed these questions in quantitative assays of reconstituted SOS-deficient chicken B-cell signaling systems combined with single-molecule measurements in supported membranes. These studies revealed an essentially one-way trafficking process in which membrane-recruited SOS remains trapped on the membrane and continuously activates Ras until being actively removed via endocytosis.

  9. Adenosine-to-inosine RNA editing affects trafficking of the gamma-aminobutyric acid type A (GABA(A)) receptor.

    Science.gov (United States)

    Daniel, Chammiran; Wahlstedt, Helene; Ohlson, Johan; Björk, Petra; Ohman, Marie

    2011-01-21

    Recoding by adenosine-to-inosine RNA editing plays an important role in diversifying proteins involved in neurotransmission. We have previously shown that the Gabra-3 transcript, coding for the α3 subunit of the GABA(A) receptor is edited in mouse, causing an isoleucine to methionine (I/M) change. Here we show that this editing event is evolutionarily conserved from human to chicken. Analyzing recombinant GABA(A) receptor subunits expressed in HEK293 cells, our results suggest that editing at the I/M site in α3 has functional consequences on receptor expression. We demonstrate that I/M editing reduces the cell surface and the total number of α3 subunits. The reduction in cell surface levels is independent of the subunit combination as it is observed for α3 in combination with either the β2 or the β3 subunit. Further, an amino acid substitution at the corresponding I/M site in the α1 subunit has a similar effect on cell surface presentation, indicating the importance of this site for receptor trafficking. We show that the I/M editing during brain development is inversely related to the α3 protein abundance. Our results suggest that editing controls trafficking of α3-containing receptors and may therefore facilitate the switch of subunit compositions during development as well as the subcellular distribution of α subunits in the adult brain. PMID:21030585

  10. Adenosine-to-Inosine RNA Editing Affects Trafficking of the γ-Aminobutyric Acid Type A (GABAA) Receptor*

    Science.gov (United States)

    Daniel, Chammiran; Wahlstedt, Helene; Ohlson, Johan; Björk, Petra; Öhman, Marie

    2011-01-01

    Recoding by adenosine-to-inosine RNA editing plays an important role in diversifying proteins involved in neurotransmission. We have previously shown that the Gabra-3 transcript, coding for the α3 subunit of the GABAA receptor is edited in mouse, causing an isoleucine to methionine (I/M) change. Here we show that this editing event is evolutionarily conserved from human to chicken. Analyzing recombinant GABAA receptor subunits expressed in HEK293 cells, our results suggest that editing at the I/M site in α3 has functional consequences on receptor expression. We demonstrate that I/M editing reduces the cell surface and the total number of α3 subunits. The reduction in cell surface levels is independent of the subunit combination as it is observed for α3 in combination with either the β2 or the β3 subunit. Further, an amino acid substitution at the corresponding I/M site in the α1 subunit has a similar effect on cell surface presentation, indicating the importance of this site for receptor trafficking. We show that the I/M editing during brain development is inversely related to the α3 protein abundance. Our results suggest that editing controls trafficking of α3-containing receptors and may therefore facilitate the switch of subunit compositions during development as well as the subcellular distribution of α subunits in the adult brain. PMID:21030585

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

    OpenAIRE

    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 GluA1-dependent synaptic plasticity for short-term memory of recently visited places, but not for the ability to form long-term associations betwee...

  12. Domoic Acid-Induced Neurotoxicity Is Mainly Mediated by the AMPA/KA Receptor: Comparison between Immature and Mature Primary Cultures of Neurons and Glial Cells from Rat Cerebellum

    Directory of Open Access Journals (Sweden)

    Helena T. Hogberg

    2011-01-01

    Full Text Available Domoic acid (DomA is a naturally occurring shellfish toxin that can induce brain damage in mammalians. Neonates have shown increased sensitivity to DomA-induced toxicity, and prenatal exposure has been associated with e.g. decreased brain GABA levels, and increased glutamate levels. Here, we evaluated DomA-induced toxicity in immature and mature primary cultures of neurons and glial cells from rat cerebellum by measuring the mRNA levels of selected genes. Moreover, we assessed if the induced toxicity was mediated by the activation of the AMPA/KA and/or the NMDA receptor. The expression of all studied neuronal markers was affected after DomA exposure in both immature and mature cultures. However, the mature cultures seemed to be more sensitive to the treatment, as the effects were observed at lower concentrations and at earlier time points than for the immature cultures. The DomA effects were completely prevented by the antagonist of the AMPA/KA receptor (NBQX, while the antagonist of the NMDA receptor (APV partly blocked the DomA-induced effects. Interestingly, the DomA-induced effect was also partly prevented by the neurotransmitter GABA. DomA exposure also affected the mRNA levels of the astrocytic markers in mature cultures. These DomA-induced effects were reduced by the addition of NBQX, APV, and GABA.

  13. 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

    -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...... 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...

  14. Human Trafficking

    Science.gov (United States)

    ... TRAFFICKING (English) Listen HUMAN TRAFFICKING (English) Published: August 2, 2012 Topics: Public ... organizations that protect and serve trafficking victims. National Human Trafficking Resource Center at 1.888.373.7888 ...

  15. 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.

  16. 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.

  17. 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.

  18. Differential modulation by AMPA of signals from red- and green-sensitive cones in carp retinal luminosity-type hori-zontal cells

    Institute of Scientific and Technical Information of China (English)

    杨如; 杨雄里

    2001-01-01

    Intracellular recordings were made from luminosity-type horizontal cells (LHCs) in the isolated superfused carp retina and the effect of AMPA (a-amino-3-hydroxy-5-methylisoxazole-4-propionic acid), a glutamate receptor agonist, on these cells was studied. AMPA suppressed the responses of LHCs driven by red-sensitive (R-) cones whereas it potentiated the responses driven by green-sensitive (G-) cones. The AMPA effect could be completely blocked by GYKI 53655, a specific AMPA receptor antagonist, indicating the exclusive involvement of AMPA-preferring receptors. The AMPA effect persisted in the presence of picrotoxin (PTX) or dihydrokainic acid (DHK), suggesting that the feedback from LHCs onto cones and glutamate transporters on cones may not be involved. It is suggested that there may exist different AMPA receptor subtypes with distinct characteristics on LHCs, which mediate signal transfer from R- and G-cones to LHCs, respectively.

  19. 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

    variants (CFP and YFP, respectively) of green fluorescent protein at various positions in the GluA2 AMPAR subunit to enable measurements of intra- receptor conformational changes using Fo¨ rster Resonance Energy Transfer (FRET) in live cells. We identify dual CFP/YFP-tagged GluA2 subunit con- structs 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...

  20. AMPA/NMDA cooperativity and integration during a single synaptic event.

    Science.gov (United States)

    Di Maio, Vito; Ventriglia, Francesco; Santillo, Silvia

    2016-10-01

    Coexistence of AMPA and NMDA receptors in glutamatergic synapses leads to a cooperative effect that can be very complex. This effect is dependent on many parameters including the relative and absolute number of the two types of receptors and biophysical parameters that can vary among synapses of the same cell. Herein we simulate the AMPA/NMDA cooperativity by using different number of the two types of receptors and considering the effect of the spine resistance on the EPSC production. Our results show that the relative number of NMDA with respect to AMPA produces a different degree of cooperation which depends also on the spine resistance. PMID:27299885

  1. Positive modulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors reverses subcronic PCP-induced deficits in the novel object recognition task in rats

    DEFF Research Database (Denmark)

    Nielsen, Trine Damgaard; Larsen, Dorrit Bjerg; Hansen, Suzanne Lisbet;

    2010-01-01

    Cognitive deficits are a major clinical unmet need in schizophrenia. The psychotomimetic drug phencyclicline (PCP) is widely applied in rodents to mimic symptoms of schizophrenia, including cognitive deficits. Precious studies have shown that sub-chronic PCP induces an enduring episodic memory...... deficit in female Lister hooded rats in teh novel object recognition (NOR) task. Here we show that positive modulation of AMPA receptor (AMPAR) mediated glutamate transmission alleviates cognitive deficits induced by sub-chronic PCP treatment. Female Lister hooded rats were treated sub......-cbronic PCP treatment induced a significant decrease in the discrimination index (DI) and both ampakines CX546 and CX516 were able to reverse this diruption of object memory in rats in the novel object recognition task. These data suggest that positive AMPAR modulation may represent a mechanism for treatment...

  2. Endocytic Trafficking towards the Vacuole Plays a Key Role in the Auxin Receptor SCFTIR-Independent Mechanism of Lateral Root Formation in A.thaliana

    Institute of Scientific and Technical Information of China (English)

    Patricio Pérez-Henríquez; Natasha V.Raikhel; Lorena Norambuena

    2012-01-01

    Plants' developmental plasticity plays a pivotal role in responding to environmental conditions.One of the most plastic plant organs is the root system.Different environmental stimuli such as nutrients and water deficiency may induce lateral root formation to compensate for a low level of water and/or nutrients.It has been shown that the hormone auxin tunes lateral root development and components for its signaling pathway have been identified.Using chemical biology,we discovered an Arabidopsis thaliana lateral root formation mechanism that is independent of the auxin receptor SCFTIR.The bioactive compound Sortin2 increased lateral root occurrence by acting upstream from the morphological marker of lateral root primordium formation,the mitotic activity.The compound did not display auxin activity.At the cellular level,Sortin2 accelerated endosomal trafficking,resulting in increased trafficking of plasma membrane recycling proteins to the vacuole.Sortin2 affected Late endosome/PVC/MVB trafficking and morphology.Combining Sortin2 with well-known drugs showed that endocytic trafficking of Late E/PVC/MVB towards the vacuole is pivotal for Sortin2induced SCFTIR-independent lateral root initiation.Our results revealed a distinctive role for endosomal trafficking in the promotion of lateral root formation via a process that does not rely on the auxin receptor complex SCFTIR.

  3. Endolysosomal trafficking of viral G protein-coupled receptor functions in innate immunity and control of viral oncogenesis.

    Science.gov (United States)

    Dong, Xiaonan; Cheng, Adam; Zou, Zhongju; Yang, Yih-Sheng; Sumpter, Rhea M; Huang, Chou-Long; Bhagat, Govind; Virgin, Herbert W; Lira, Sergio A; Levine, Beth

    2016-03-15

    The ubiquitin-proteasome system degrades viral oncoproteins and other microbial virulence factors; however, the role of endolysosomal degradation pathways in these processes is unclear. Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma, and a constitutively active viral G protein-coupled receptor (vGPCR) contributes to the pathogenesis of KSHV-induced tumors. We report that a recently discovered autophagy-related protein, Beclin 2, interacts with KSHV GPCR, facilitates its endolysosomal degradation, and inhibits vGPCR-driven oncogenic signaling. Furthermore, monoallelic loss of Becn2 in mice accelerates the progression of vGPCR-induced lesions that resemble human Kaposi's sarcoma. Taken together, these findings indicate that Beclin 2 is a host antiviral molecule that protects against the pathogenic effects of KSHV GPCR by facilitating its endolysosomal degradation. More broadly, our data suggest a role for host endolysosomal trafficking pathways in regulating viral pathogenesis and oncogenic signaling. PMID:26929373

  4. Role of Hippocampal 5-HT1A Receptor and Its Modulation to NMDA Receptor and AMPA Receptor in Depression Induced by Chronic Unpredictable Mild Stress%应激性抑郁样行为发生中海马5-羟色胺1A受体的作用及其对NMDA受体和AMPA受体的调节

    Institute of Scientific and Technical Information of China (English)

    问黎敏; 安书成; 刘慧

    2012-01-01

    为探讨慢性不可预见性温和应激(chronic unpredictable mild stress,CUMS)诱发抑郁样行为发生中海马5-羟色胺1A受体(5-hydroxytryptamine receptor 1A,5-HT1AR)表达与作用,及其对谷氨酸N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid,NMDA)受体和α-氨基羟甲基异恶唑丙酸(α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid,AMPA)受体的影响.通过建立CUMS动物模型,给应激抑郁模型大鼠海马微量注射5-HT1A受体激动剂、给正常大鼠海马微量注射5-HT1A受体拮抗剂,测量大鼠体重变化率,并采用糖水偏爱测试、旷场实验和悬尾实验等方法对大鼠进行行为学检测,运用Western blot和ELISA方法检测大鼠海马组织中5-HT1AR和NMDAR和AMPAR的关键亚基的表达以及磷酸化水平.结果显示,与对照组相比,CUMS组大鼠表现出抑郁样行为,海马5-HT1AR、AMPA受体的GluR2/3亚基表达及磷酸化明显降低,NMDA受体的NR1和NR2B亚基表达及磷酸化显著增加;正常大鼠海马微量注射5-HT1A受体拮抗剂WAY100635,动物行为学表现及AMPA受体、NMDA受体表达及磷酸化水平均与CUMS组相同;注射5-HT1A受体激动剂8-OH-DPAT能逆转应激诱导的上述改变.以上结果表明,CUMS诱发抑郁榉行为与海马5-HT1AR表达下降,AMPAR表达量及磷酸化水平降低,NMDAR表达量及磷酸化水平升高有关.5-HT通过5-HT1AR产生抗抑郁作用.5-HT1AR激动剂抗抑郁作用与降低NMDAR表达量及磷酸化水平,提高AMPAR表达量及磷酸化水平密切相关.%Stressors markedly influence central neurochemical and hormonal processes and thus play a pivotal role in the occurrence of depressive illnesses. As the center for stress response and the potential target for stressfulprovocation, the hippocampus is becoming a focus in depression research. Although a large number of behavioral paradigms have been proposed as animal models of depression, only a few are considered potentially useful research tools with

  5. Importance of constitutive activity and arrestin-independent mechanisms for intracellular trafficking of the ghrelin receptor

    DEFF Research Database (Denmark)

    Holliday, Nicholas D; Holst, Birgitte; Rodionova, Elena A;

    2007-01-01

    . Furthermore the interaction between phosphorylated receptors and beta-arrestin adaptor proteins has been examined. Replacement of the FLAG-tagged GhrelinR C tail with the equivalent GPR39 domain (GhR-39 chimera) preserved G(q) signaling. However in contrast to the GhrelinR, GhR-39 receptors exhibited no basal...

  6. Real-time trafficking and signaling of the glucagon-like peptide-1 receptor

    DEFF Research Database (Denmark)

    Roed, Sarah Noerklit; Wismann, Pernille; Underwood, Christina Rye;

    2014-01-01

    The glucagon-like peptide-1 incretin receptor (GLP-1R) of family B G protein-coupled receptors (GPCRs) is a major drug target in type-2-diabetes due to its regulatory effect on post-prandial blood-glucose levels. The mechanism(s) controlling GLP-1R mediated signaling are far from fully understood...

  7. Regulation of Epidermal Growth Factor Receptor Trafficking by Lysine Deacetylase HDAC6

    DEFF Research Database (Denmark)

    Lissanu Deribe, Yonathan; Wild, Philipp; Chandrashaker, Akhila;

    2009-01-01

    Binding of epidermal growth factor (EGF) to its receptor leads to receptor dimerization, assembly of protein complexes, and activation of signaling networks that control key cellular responses. Despite their fundamental role in cell biology, little is known about protein complexes associated...

  8. Phosphorylation of threonine 333 regulates trafficking of the human sst5 somatostatin receptor.

    Science.gov (United States)

    Petrich, Aline; Mann, Anika; Kliewer, Andrea; Nagel, Falko; Strigli, Anne; Märtens, Jan Carlo; Pöll, Florian; Schulz, Stefan

    2013-04-01

    The frequent overexpression of the somatostatin receptors sst2 and sst5 in neuroendocrine tumors provides the molecular basis for therapeutic application of novel multireceptor somatostatin analogs. Although the phosphorylation of the carboxyl-terminal region of the sst2 receptor has been studied in detail, little is known about the agonist-induced regulation of the human sst5 receptor. Here, we have generated phosphosite-specific antibodies for the carboxyl-terminal threonines 333 (T333) and 347 (T347), which enabled us to selectively detect either the T333-phosphorylated or the T347-phosphorylated form of sst5. We show that agonist-mediated phosphorylation occurs at T333, whereas T347 is constitutively phosphorylated in the absence of agonist. We further demonstrate that the multireceptor somatostatin analog pasireotide and the sst5-selective ligand L-817,818 but not octreotide or KE108 were able to promote a detectable T333 phosphorylation. Interestingly, BIM-23268 was the only sst5 agonist that was able to stimulate T333 phosphorylation to the same extent as natural somatostatin. Agonist-induced T333 phosphorylation was dose-dependent and selectively mediated by G protein-coupled receptor kinase 2. Similar to that observed for the sst2 receptor, phosphorylation of sst5 occurred within seconds. However, unlike that seen for the sst2 receptor, dephosphorylation and recycling of sst5 were rapidly completed within minutes. We also identify protein phosphatase 1γ as G protein-coupled receptor phosphatase for the sst5 receptor. Together, we provide direct evidence for agonist-selective phosphorylation of carboxyl-terminal T333. In addition, we identify G protein-coupled receptor kinase 2-mediated phosphorylation and protein phosphatase 1γ-mediated dephosphorylation of T333 as key regulators of rapid internalization and recycling of the human sst5 receptor.

  9. AMPA experimental communications systems

    Science.gov (United States)

    Beckerman, D.; Fass, S.; Keon, T.; Sielman, P.

    1982-01-01

    The program was conducted to demonstrate the satellite communication advantages of Adaptive Phased Array Technology. A laboratory based experiment was designed and implemented to demonstrate a low earth orbit satellite communications system. Using a 32 element, L-band phased array augmented with 4 sets of weights (2 for reception and 2 for transmission) a high speed digital processing system and operating against multiple user terminals and interferers, the AMPA system demonstrated: communications with austere user terminals, frequency reuse, communications in the face of interference, and geolocation. The program and experiment objectives are described, the system hardware and software/firmware are defined, and the test performed and the resultant test data are presented.

  10. UNC50 prompts G1/S transition and proliferation in HCC by regulation of epidermal growth factor receptor trafficking.

    Directory of Open Access Journals (Sweden)

    Zhou Fang

    Full Text Available UNC50 has long been recognized as a Golgi apparatus protein in yeast, and is involved in nicotinic receptor trafficking in Caenorhabditis elegans, but little is known about UNC50 gene function in human biology despite it being conserved from yeast to high eukaryotes.We investigated the relation between UNC50 and human hepatocellular carcinoma (HCC and the potential mechanisms underlying HCC development.UNC50 mRNA expression patterns in 12 HCC and adjacent non-cancerous tissues determined using northern blotting were confirmed by real-time PCR in another 44 paired tissues. Microarray experiments were used to screen for global effects of UNC50 knockdown in the Hep3B cell line, and were confirmed by real-time PCR, western blotting, flow cytometry, and tetrazolium assay in both UNC50 overexpression and knockdown Hep3B cells.UNC50 expression levels were upregulated in HCC tissues in comparison with the adjacent non-cancerous tissues. UNC50 knockdown reduced mRNA levels of the downstream targets of the epidermal growth factor receptor (EGFR pathway: cyclin D1 (CCND1, EGF, matrix metalloproteinase-7 (MMP7, aldose reductase-like 1 (AKR1B10, cell surface-associated mucin 1 (MUC1, and gastrin (GAST. Moreover, UNC50 influenced EGF, inducing cell cycle entry by affecting cell surface EGFR amounts.UNC50 may plays some roles in HCC progression by affecting the EGFR pathway.

  11. Synthesis and biological evaluation of analogues of 7-chloro-4,5-dihydro-4- oxo-8-(1,2,4-triazol-4-yl)-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylic acid (TQX-173) as novel selective AMPA receptor antagonists.

    Science.gov (United States)

    Catarzi, Daniela; Colotta, Vittoria; Varano, Flavia; Calabri, Francesca Romana; Filacchioni, Guido; Galli, Alessandro; Costagli, Chiara; Carlà, Vincenzo

    2004-01-01

    In recent papers (Catarzi, D.; et al. J. Med. Chem. 2000, 43, 3824-3826; 2001, 44, 3157-3165) we reported chemical and biological studies on 4,5-dihydro-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylates (TQXs) bearing different nitrogen-containing heterocycles at position-8. In particular, from these studies it emerged that both the 7-chloro-4,5-dihydro-4-oxo-8-(1,2,4-triazol-4-yl)-1,2,4-triazolo[1,5-a] quinoxaline-2-carboxylic acid TQX-173 (compound B) and its corresponding ethyl ester (compound A) were the most active and selective compounds of this series. In pursuing our investigation on the structure-activity relationships of these TQX derivatives, different electron-withdrawing groups (CF(3), NO(2)) were introduced at position 7 on the TQX ring system, replacing the 7-chloro substituent of B and of other selected 8-heteroaryltriazoloquinoxaline-2-carboxylates previously described. All the newly synthesized compounds were biologically evaluated for their binding at the Gly/NMDA, AMPA, and KA high-affinity receptors. Gly/NMDA binding assays were performed to assess the selectivity of the reported compounds toward the AMPA receptor. Compounds endowed with micromolar binding affinity for the KA high-affinity binding site were also evaluated for their binding at the KA low-affinity receptor. Some selected compounds were also tested for their functional antagonist activity at the AMPA and NMDA receptor-ion channel complex. The results obtained in this study have pointed out that 4,5-dihydro-7-nitro-4-oxo-8-(3-carboxypyrrol-1-yl)-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylic acid (9b) and its corresponding ethyl ester (9a) are the most potent and selective AMPA receptor antagonists reported to date among the TQX series.

  12. 鞘内注射NMDA和AMPA受体激动剂或拮抗剂对异丙酚抗伤害作用的影响%Effects of intrathecal NMDA and AMPA receptors agonists or antagonists on antinociception of propofol

    Institute of Scientific and Technical Information of China (English)

    许爱军; 段世明; 曾因明

    2004-01-01

    AIM: To study the effects of intrathecal (it) agonists and antagonists of N-methyl-D-aspartate (NMDA) and alphaamino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors and NMDAR1 antisenseoligodeoxynucleotides (AS ODN) on the antinociception of propofol. METHODS: Hot-plate test (HPPT) and acetic acid-induced writhing test were used to measure the nociceptive thresholds in mice. The effects of intrathecal NMDA, AMPA, MK-801, NBQX, or NMDAR1 AS ODN on the antinociception of propofol were observed.RESULTS: Propofol (25, 50 mg/kg, ip) displayed an appreciable antinociceptive effect in hot-plate test and acetic acid-induced writhing test. NMDA (12.5, 25 ng, it) or AMPA (1.25, 2.5 ng, it) exhibited no effects on the behavior but decreased HPPT significantly compared with basal HPPT and aCSF group (P<0.05, P<0.01). No effects on behavior and HPPT were obtained in NMDA (6.25 ng, it) or AMPA (0.625 ng, it) groups. NMDA (6.25, 12.5, and 25 ng, it) dose-dependently decreased the HPPT in propofol-treated group. AMPA (1.25, 2.5 ng, it) also decreased HPPT significantly. MK-801 (0.25, 0.5 μg, it) or NBQX (0.25, 0.5 μg, it) groups had no behavioral changes, two antagonists 0.5 μg but not 0.25 μg increased HPPT in conscious or propofol-treated mice. AS ODN (5, 10, and 20 μg, it) groups exhibited dose-dependent increased in HPPT in propofol-treated groups compared with aCSF group (P<0.05, P<0.01). CONCLUSION: Both agonists NMDA and AMPA reversed the antinociception of propofol.MK-801, NBQX, and NMDAR1 AS ODN potentiated the antinociceptive effects of propofol. Propofol produced antinociception through an interaction with spinal NMDA and AMPA receptors in mice.

  13. Differential regulation of δ-opioid receptor trafficking after internalization by TIPP and DPDPE

    Institute of Scientific and Technical Information of China (English)

    Min-huaHONG; Yi-minTAO; Xue-junXU; Zhi-qiangCHI; Jing-genLIU

    2004-01-01

    AIM: To explore the mechanisms underlying the difference between TIPP and DPDPE in desensitization of the δ-opioidreceptors. METHODS: GH3 cells stably expressing HA-tagged δ-opioid receptors were treated with TIPP, DPDPE (1 μmol/L)or morphine (10 μmol/L) for different periods of time in the presence or absence of 50 μmol/L monensin or 10 nmol/L OA.Internalization of δ-opioid receptor was assessed using confocal

  14. Fluorescently labeled adrenomedullin allows real-time monitoring of adrenomedullin receptor trafficking in living cells.

    Science.gov (United States)

    Schönauer, Ria; Kaiser, Anette; Holze, Cathleen; Babilon, Stefanie; Köbberling, Johannes; Riedl, Bernd; Beck-Sickinger, Annette G

    2015-12-01

    The human adrenomedullin (ADM) is a 52 amino acid peptide hormone belonging to the calcitonin family of peptides, which plays a major role in the development and regulation of cardiovascular and lymphatic systems. For potential use in clinical applications, we aimed to investigate the fate of the peptide ligand after binding and activation of the adrenomedullin receptor (AM1), a heterodimer consisting of the calcitonin receptor-like receptor (CLR), a G protein-coupled receptor, associated with the receptor activity-modifying protein 2 (RAMP2). Full length and N-terminally shortened ADM peptides were synthesized using Fmoc/tBu solid phase peptide synthesis and site-specifically labeled with the fluorophore carboxytetramethylrhodamine (Tam) either by amide bond formation or copper(I)-catalyzed azide alkyne cycloaddition. For the first time, Tam-labeled ligands allowed the observation of co-internalization of the whole ligand-receptor complex in living cells co-transfected with fluorescent fusion proteins of CLR and RAMP2. Application of a fluorescent probe to track lysosomal compartments revealed that ADM together with the CLR/RAMP2-complex is routed to the degradative pathway. Moreover, we found that the N-terminus of ADM is not a crucial component of the peptide sequence in terms of AM1 internalization behavior. PMID:26767744

  15. CHILD TRAFFICKING

    OpenAIRE

    Pallavi Chincholkar

    2016-01-01

    Human trafficking is the third biggest beneficial industry on the planet. Child trafficking unlike many other issues is found in both developed and developing nations. NGOs evaluate that 12,000 - 50,000 ladies and kids are trafficked into the nation every year from neighboring states for the sex exchange.

  16. Functional Proteomics Defines the Molecular Switch Underlying FGF Receptor Trafficking and Cellular Outputs

    DEFF Research Database (Denmark)

    Francavilla, Chiara; Rigbolt, Kristoffer T.G.; Emdal, Kristina B;

    2013-01-01

    The stimulation of fibroblast growth factor receptors (FGFRs) with distinct FGF ligands generates specific cellular responses. However, the mechanisms underlying this paradigm have remained elusive. Here, we show that FGF-7 stimulation leads to FGFR2b degradation and, ultimately, cell proliferation...... recruitment. This complex is crucial for FGFR2b recycling and responses, given that FGF-10 stimulation of either FGFR2b_Y734F mutant- or SH3BP4-depleted cells switches the receptor endocytic route to degradation, resulting in decreased breast cancer cell migration and the inhibition of epithelial branching...

  17. Effect of C-Terminal S-Palmitoylation on D2 Dopamine Receptor Trafficking and Stability.

    Directory of Open Access Journals (Sweden)

    Brittany Ebersole

    Full Text Available We have used bioorthogonal click chemistry (BCC, a sensitive non-isotopic labeling method, to analyze the palmitoylation status of the D2 dopamine receptor (D2R, a G protein-coupled receptor (GPCR crucial for regulation of processes such as mood, reward, and motor control. By analyzing a series of D2R constructs containing mutations in cysteine residues, we found that palmitoylation of the D2R most likely occurs on the C-terminal cysteine residue (C443 of the polypeptide. D2Rs in which C443 was deleted showed significantly reduced palmitoylation levels, plasma membrane expression, and protein stability compared to wild-type D2Rs. Rather, the C443 deletion mutant appeared to accumulate in the Golgi, indicating that palmitoylation of the D2R is important for cell surface expression of the receptor. Using the full-length D2R as bait in a membrane yeast two-hybrid (MYTH screen, we identified the palmitoyl acyltransferase (PAT zDHHC4 as a D2R interacting protein. Co-immunoprecipitation analysis revealed that several other PATs, including zDHHC3 and zDHHC8, also interacted with the D2R and that each of the three PATs was capable of affecting the palmitoylation status of the D2R. Finally, biochemical analyses using D2R mutants and the palmitoylation blocker, 2-bromopalmitate indicate that palmitoylation of the receptor plays a role in stability of the D2R.

  18. New hyperekplexia mutations provide insight into glycine receptor assembly, trafficking, and activation mechanisms

    DEFF Research Database (Denmark)

    Bode, Anna; Wood, Sian-Elin; Mullins, Jonathan G L;

    2013-01-01

    to hyperekplexia. Most hyperekplexia cases are caused by mutations in the α1 subunit of the human glycine receptor (hGlyR) gene (GLRA1). Here we analyzed 68 new unrelated hyperekplexia probands for GLRA1 mutations and identified 19 mutations, of which 9 were novel. Electrophysiological analysis demonstrated...

  19. Analysis of GPCR Localization and Trafficking

    Science.gov (United States)

    Hislop, James N.; von Zastrow, Mark

    2016-01-01

    Localization and trafficking of G protein-coupled receptors (GPCRs) is increasingly recognized to play a fundamental role in receptor-mediated signaling and its regulation. Individual receptors, including closely homologous subtypes with otherwise similar functional properties, can differ considerably in their membrane trafficking properties. In this chapter, we describe several approaches for experimentally assessing the subcellular localization and trafficking of selected GPCRs. Firstly, we describe a flexible method for receptor localization using fluorescence microscopy. We then describe two complementary approaches, using fluorescence flow cytometry and surface biotinylation, for examining receptor internalization and trafficking in the endocytic pathway. PMID:21607873

  20. Antidepressant Effects of AMPA and Ketamine Combination: Role of Hippocampal BDNF, Synapsin, and mTOR

    Science.gov (United States)

    Akinfiresoye, Luli; Tizabi, Yousef

    2013-01-01

    Rationale A number of preclinical and clinical studies suggest ketamine, a glutamate NMDA (N-methyl-D-aspartate) receptor antagonist, has a rapid and lasting antidepressant effect when administered either acutely or chronically. It has been postulated that this effect is due to stimulation of AMPA (alpha-amino-3-hydroxy-5-methyl–4-isoxazolepropionic acid) receptors. Objective In this study, we tested whether AMPA alone has an antidepressant effect and if the combination of AMPA and ketamine provides added benefit in Wistar-Kyoto (WKY) rats, a putative animal model of depression. Results Chronic AMPA treatment resulted in a dose dependent antidepressant effect in both the forced swim test (FST) and sucrose preference test. Moreover, chronic administration (10–11d) of combinations of AMPA and ketamine, at doses that were ineffective on their own, resulted in a significant antidepressant effect. The behavioral effects were associated with increases in hippocampal brain derived neurotrophic factor (BDNF), synapsin, and mammalian target of rapamycin (mTOR). Conclusion These findings are the first to provide evidence for an antidepressant effect of AMPA, and suggest the usefulness of AMPA-ketamine combination in treatment of depression. Furthermore, these effects appear to be associated with increases in markers of hippocampal neurogenesis and synaptogenesis, suggesting a mechanism of their action. PMID:23732839

  1. DISC1 Protein Regulates γ-Aminobutyric Acid, Type A (GABAA) Receptor Trafficking and Inhibitory Synaptic Transmission in Cortical Neurons.

    Science.gov (United States)

    Wei, Jing; Graziane, Nicholas M; Gu, Zhenglin; Yan, Zhen

    2015-11-13

    Association studies have suggested that Disrupted-in-Schizophrenia 1 (DISC1) confers a genetic risk at the level of endophenotypes that underlies many major mental disorders. Despite the progress in understanding the significance of DISC1 at neural development, the mechanisms underlying DISC1 regulation of synaptic functions remain elusive. Because alterations in the cortical GABA system have been strongly linked to the pathophysiology of schizophrenia, one potential target of DISC1 that is critically involved in the regulation of cognition and emotion is the GABAA receptor (GABAAR). We found that cellular knockdown of DISC1 significantly reduced GABAAR-mediated synaptic and whole-cell current, whereas overexpression of wild-type DISC1, but not the C-terminal-truncated DISC1 (a schizophrenia-related mutant), significantly increased GABAAR currents in pyramidal neurons of the prefrontal cortex. These effects were accompanied by DISC1-induced changes in surface GABAAR expression. Moreover, the regulation of GABAARs by DISC1 knockdown or overexpression depends on the microtubule motor protein kinesin 1 (KIF5). Our results suggest that DISC1 exerts an important effect on GABAergic inhibitory transmission by regulating KIF5/microtubule-based GABAAR trafficking in the cortex. The knowledge gained from this study would shed light on how DISC1 and the GABA system are linked mechanistically and how their interactions are critical for maintaining a normal mental state. PMID:26424793

  2. Trafficking of α1B-adrenergic receptor mediated by inverse agonist in living cells

    Institute of Scientific and Technical Information of China (English)

    MingXU; Ying-huaGUAN; NingXU; Zhang-yiLIANG; Shu-yiWang; YaoSONG; Chi-deHAN; Xin-shengZHAO; You-yiZHANG

    2005-01-01

    AIM The project is aimed at understanding the action of inverse agonist at single molecule level and capturing the real time picture of molecular behavior of α1B-adrenergic receptor (AR) mediated by inverse agonist in living cells by single molecule detection (SMD). METHODS The location and distribution of α1B-AR was detected by laser confocal and whole cell 3H-prazosin binding assay. Dynamic imaging of BODIPY-FL-labeled prazosin (Praz), specific antagonist of (1-AR, was observed in α1B-AR stably expressed human embryonic kidney 293 (HEK293) living cells. The detection of real-time dynamic behaviors of AR was achieved by using fluorescence-labeled AR and its ligand combined with SMD techniques. RESULTS α1B-AR was predominantly distributed on the cell surface and 8.2% of the total receptors were located in cytosol.

  3. A role of Rab29 in the integrity of the trans-Golgi network and retrograde trafficking of mannose-6-phosphate receptor.

    Directory of Open Access Journals (Sweden)

    Shicong Wang

    Full Text Available Rab29 (also referred as Rab7L1 is a novel Rab protein, and is recently demonstrated to regulate phagocytosis and traffic from the Golgi to the lysosome. However, its roles in membrane trafficking have not been investigated extensively. Our results in this study revealed that Rab29 is associated with the trans-Golgi network (TGN, and is essential for maintaining the integrity of the TGN, because inhibition of the activity of Rab29 or depletion of Rab29 resulted in fragmentation of the TGN marked by TGN46. Expression of the dominant negative form Rab29T21N or shRNA-Rab29 also altered the distribution of mannose-6-phosphate receptor (M6PR, and interrupted the retrograde trafficking of M6PR through monitoring the endocytosis of CD8-tagged calcium dependent M6PR (cdM6PR or calcium independent M6PR (ciM6PR, but without significant effects on the anterograde trafficking of vesicular stomatitis virus G protein (VSV-G. Our results suggest that Rab29 is essential for the integrity of the TGN and participates in the retrograde trafficking of M6PRs.

  4. A Role of Rab29 in the Integrity of the Trans-Golgi Network and Retrograde Trafficking of Mannose-6-Phosphate Receptor

    Science.gov (United States)

    Wang, Shicong; Ma, Zexu; Xu, Xiaohui; Wang, Zhen; Sun, Lixiang; Zhou, Yunhe; Lin, Xiaosi; Hong, Wanjin; Wang, Tuanlao

    2014-01-01

    Rab29 (also referred as Rab7L1) is a novel Rab protein, and is recently demonstrated to regulate phagocytosis and traffic from the Golgi to the lysosome. However, its roles in membrane trafficking have not been investigated extensively. Our results in this study revealed that Rab29 is associated with the trans-Golgi network (TGN), and is essential for maintaining the integrity of the TGN, because inhibition of the activity of Rab29 or depletion of Rab29 resulted in fragmentation of the TGN marked by TGN46. Expression of the dominant negative form Rab29T21N or shRNA-Rab29 also altered the distribution of mannose-6-phosphate receptor (M6PR), and interrupted the retrograde trafficking of M6PR through monitoring the endocytosis of CD8-tagged calcium dependent M6PR (cdM6PR) or calcium independent M6PR (ciM6PR), but without significant effects on the anterograde trafficking of vesicular stomatitis virus G protein (VSV-G). Our results suggest that Rab29 is essential for the integrity of the TGN and participates in the retrograde trafficking of M6PRs. PMID:24788816

  5. Poliovirus trafficking toward central nervous system via human poliovirus receptor-dependent and -independent pathway.

    Directory of Open Access Journals (Sweden)

    Seii eOHKA

    2012-04-01

    Full Text Available In humans, paralytic poliomyelitis results from the invasion of the central nervous system by circulating poliovirus (PV via the blood-brain barrier (BBB. After the virus enters the central nervous system (CNS, it replicates in neurons, especially in motor neurons (MNs, inducing the cell death that causes paralytic poliomyelitis. Along with this route of dissemination, neural pathway has been reported in humans, monkeys, and PV-sensitive human PV receptor (hPVR/CD155-transgenic (Tg mice. We demonstrated that a fast retrograde axonal transport process is required for PV dissemination through the sciatic nerve of hPVR-Tg mice and that intramuscularly inoculated PV causes paralysis in a hPVR-dependent manner. We also showed that hPVR-independent axonal transport of PV exists in hPVR-Tg and non-Tg mice, indicating that several different pathways for PV axonal transport exist in these mice. Circulating PV after intravenous inoculation in mice cross the BBB at a high rate in a hPVR-independent manner. Recently, we identified transferrin receptor 1 (TfR1 of mouse brain capillary endothelial cells as a binding protein to PV, implicating that TfR1 is a possible receptor for PV to permeate the BBB.

  6. 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

  7. Role of hippocampal AMPA receptors in antidepressant effect of ketamine in rats%海马AMPA受体在氯胺酮对大鼠抗抑郁效应中的作用

    Institute of Scientific and Technical Information of China (English)

    杨春; 高志勤; 杨春; 周志强; 杨建军; 徐建国

    2012-01-01

    Objective To evaluate the role of hippocampal AMPA receptors in the antidepressant effect of ketamine in rats.Methods Thirty male Wistar rats aged 2 months weighing 180-220 g were randomly divided into 3 groups (n =10 each):control group (group C); ketamine group (group K) and AMPA receptor antagonist NBQX group (group N).The animals were forced to swim for 15 min on the 1st day.On the 2nd day,NBQX 10 mg/kg was injected intrapefitoneally in group N; 30 min later,normal saline was injected intraperitoneally in group C,while ketamine 10 mg/kg was injected intraperitoneally in groups K and N.The forced swimming test was performed again for 5 min at 30 min after administration and the immobility time of the rats was recorded.Then the animals were sacrificed and the hippocampus was removed for determination of the expression of phosphorylated rapamycin (p-mTOR) and phosphorylated glutamate receptor 1 (p-GluR1).Results Compared with group C,the immobility time was significantly shortened and the expression of p-mTOR and p-GluR1 up-regulated in group K,and the immobility time was significantly shortened,the expression of p-mTOR up-regulated and the expression of p-GluR1 down-regulated in group N (P < 0.05).Compared with group K,the immobility time was significantly prolonged and the expression of p-mTOR and p-GluR1 down-regulated in group N (P < 0.05 ).Conclusion AMPA receptors in hippocampus are involved in the antidepressant effect of ketamine in rats and the inhibition of mTOR and GluR1 activities may be involved in the mechanism.%目的 评价海马α-氨基-3-羟基-5-甲基-4-异恶唑基丙酸(AMPA)受体在氯胺酮对大鼠抗抑郁效应中的作用.方法 雄性Wistar大鼠30只,2月龄,体重180~220 g,采用随机数字表法,将其随机均分为3组(n=10):对照组(C组)、氯胺酮组(K组)和AMPA受体拮抗剂NBQX组(N组).行强迫游泳实验15 min建立大鼠抑郁模型.于第2天N组腹腔注射NBQX 10 mg/kg;30 min

  8. Alterations in Hippocampal Oxidative Stress, Expression of AMPA Receptor GluR2 Subunit and Associated Spatial Memory Loss by Bacopa monnieri Extract (CDRI-08 in Streptozotocin-Induced Diabetes Mellitus Type 2 Mice.

    Directory of Open Access Journals (Sweden)

    Surya P Pandey

    Full Text Available Bacopa monnieri extract has been implicated in the recovery of memory impairments due to various neurological disorders in animal models and humans. However, the precise molecular mechanism of the role of CDRI-08, a well characterized fraction of Bacopa monnieri extract, in recovery of the diabetes mellitus-induced memory impairments is not known. Here, we demonstrate that DM2 mice treated orally with lower dose of CDRI-08 (50- or 100 mg/kg BW is able to significantly enhance spatial memory in STZ-DM2 mice and this is correlated with a significant decline in oxidative stress and up regulation of the AMPA receptor GluR2 subunit gene expression in the hippocampus. Treatment of DM2 mice with its higher dose (150 mg/kg BW or above shows anti-diabetic effect in addition to its ability to recover the spatial memory impairment by reversing the DM2-induced elevated oxidative stress and decreased GluR2 subunit expression near to their values in normal and CDRI-08 treated control mice. Our results provide evidences towards molecular basis of the memory enhancing and anti diabetic role of the Bacopa monnieri extract in STZ-induced DM2 mice, which may have therapeutic implications.

  9. Radiosynthesis and preliminary PET evaluation of (18)F-labeled 2-(1-(3-fluorophenyl)-2-oxo-5-(pyrimidin-2-yl)-1,2-dihydropyridin-3-yl)benzonitrile for imaging AMPA receptors.

    Science.gov (United States)

    Yuan, Gengyang; Jones, Graham B; Vasdev, Neil; Liang, Steven H

    2016-10-01

    To prompt the development of (18)F-labeled positron emission tomography (PET) tracers for the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, we have prepared (18)F-labeled 2-(1-(3-fluorophenyl)-2-oxo-5-(pyrimidin-2-yl)-1,2-dihydropyridin-3-yl)benzonitrile ([(18)F]8). The radiosynthesis was achieved by a one-pot two-step method that utilized a spirocyclic hypervalent iodine(III) mediated radiofluorination to prepare the (18)F-labeled 1-bromo-3-fluorobenzene ([(18)F]15) intermediate with K(18)F. A subsequent copper(I) iodide mediated coupling reaction was carried out with 2-(2-oxo-5-(pyrimidin-2-yl)-1,2-dihydropyridin-3-yl)benzonitrile (10) to [(18)F]8 in 10±2% uncorrected radiochemical yield relative to starting (18)F-fluoride with >99% radiochemical purity and 29.6±7.4Gbq/μmol specific activity at the time of injection. PET imaging studies with the title radiotracer in normal mice demonstrated good brain uptake (peak standardized uptake value (SUV)=2.3±0.1) and warrants further in vivo validation.

  10. The CD20 homologue MS4A4 directs trafficking of KIT toward clathrin-independent endocytosis pathways and thus regulates receptor signaling and recycling.

    Science.gov (United States)

    Cruse, Glenn; Beaven, Michael A; Music, Stephen C; Bradding, Peter; Gilfillan, Alasdair M; Metcalfe, Dean D

    2015-05-01

    MS4A family members differentially regulate the cell cycle, and aberrant, or loss of, expression of MS4A family proteins has been observed in colon and lung cancer. However, the precise functions of MS4A family proteins and their mechanistic interactions remain unsolved. Here we report that MS4A4 facilitates trafficking of the receptor tyrosine kinase KIT through endocytic recycling rather than degradation pathways by a mechanism that involves recruitment of KIT to caveolin-1-enriched microdomains. Silencing of MS4A4 in human mast cells altered ligand-induced KIT endocytosis pathways and reduced receptor recycling to the cell surface, thus promoting KIT signaling in the endosomes while reducing that in the plasma membrane, as exemplified by Akt and PLCγ1 phosphorylation, respectively. The altered endocytic trafficking of KIT also resulted in an increase in SCF-induced mast cell proliferation and migration, which may reflect altered signaling in these cells. Our data reveal a novel function for MS4A family proteins in regulating trafficking and signaling, which could have implications in both proliferative and immunological diseases. PMID:25717186

  11. Protease-Activated Receptor 4 Variant p.Tyr157Cys Reduces Platelet Functional Responses and Alters Receptor Trafficking

    OpenAIRE

    Norman, Jane E; Cunningham, Margaret R; Jones, Matthew L.; Walker, Mary E; Westbury, Sarah K; Sessions, Richard B.; Mundell, Stuart J.; Mumford, Andrew D.

    2016-01-01

    OBJECTIVE: Protease-activated receptor 4 (PAR4) is a key regulator of platelet reactivity and is encoded by F2RL3, which has abundant rare missense variants. We aimed to provide proof of principle that rare F2LR3 variants potentially affect platelet reactivity and responsiveness to PAR1 antagonist drugs and to explore underlying molecular mechanisms.APPROACH AND RESULTS: We identified 6 rare F2RL3 missense variants in 236 cardiac patients, of which the variant causing a tyrosine 157 to cystei...

  12. Protease-activated Receptor-4 Signaling and Trafficking Is Regulated by the Clathrin Adaptor Protein Complex-2 Independent of β-Arrestins.

    Science.gov (United States)

    Smith, Thomas H; Coronel, Luisa J; Li, Julia G; Dores, Michael R; Nieman, Marvin T; Trejo, JoAnn

    2016-08-26

    Protease-activated receptor-4 (PAR4) is a G protein-coupled receptor (GPCR) for thrombin and is proteolytically activated, similar to the prototypical PAR1. Due to the irreversible activation of PAR1, receptor trafficking is intimately linked to signal regulation. However, unlike PAR1, the mechanisms that control PAR4 trafficking are not known. Here, we sought to define the mechanisms that control PAR4 trafficking and signaling. In HeLa cells depleted of clathrin by siRNA, activated PAR4 failed to internalize. Consistent with clathrin-mediated endocytosis, expression of a dynamin dominant-negative K44A mutant also blocked activated PAR4 internalization. However, unlike most GPCRs, PAR4 internalization occurred independently of β-arrestins and the receptor's C-tail domain. Rather, we discovered a highly conserved tyrosine-based motif in the third intracellular loop of PAR4 and found that the clathrin adaptor protein complex-2 (AP-2) is important for internalization. Depletion of AP-2 inhibited PAR4 internalization induced by agonist. In addition, mutation of the critical residues of the tyrosine-based motif disrupted agonist-induced PAR4 internalization. Using Dami megakaryocytic cells, we confirmed that AP-2 is required for agonist-induced internalization of endogenous PAR4. Moreover, inhibition of activated PAR4 internalization enhanced ERK1/2 signaling, whereas Akt signaling was markedly diminished. These findings indicate that activated PAR4 internalization requires AP-2 and a tyrosine-based motif and occurs independent of β-arrestins, unlike most classical GPCRs. Moreover, these findings are the first to show that internalization of activated PAR4 is linked to proper ERK1/2 and Akt activation. PMID:27402844

  13. Differential expression of postsynaptic NMDA and AMPA receptor subunits in the hippocampus and prefrontal cortex of the Flinders Sensitive Line rat model of depression

    DEFF Research Database (Denmark)

    Treccani, Giulia; du Jardin, Kristian Gaarn; Wegener, Gregers;

    2016-01-01

    "Using a subcellular fractionation approach for purification of the Triton-Insoluble postsynaptic Fraction (TIF), the authors show altered expression of NMDA receptor subunits in the hippocampus of the Flinders Sensitive Line rat model of depression. Altered composition of NMDA receptors may...... represent a critical component of the depressive-like behaviors observed in this model. " This article is protected by copyright. All rights reserved....

  14. Human Trafficking

    Science.gov (United States)

    Wilson, David McKay

    2011-01-01

    The shadowy, criminal nature of human trafficking makes evaluating its nature and scope difficult. The U.S. State Department and anti-trafficking groups estimate that worldwide some 27 million people are caught in a form of forced servitude today. Public awareness of modern-day slavery is gaining momentum thanks to new abolitionist efforts. Among…

  15. The CD20 homologue MS4A4 directs trafficking of KIT toward clathrin-independent endocytosis pathways and thus regulates receptor signaling and recycling

    OpenAIRE

    Cruse, Glenn; Beaven, Michael A.; Music, Stephen C.; Bradding, Peter; Gilfillan, Alasdair M.; Dean D. Metcalfe

    2015-01-01

    MS4A family members differentially regulate the cell cycle, and aberrant, or loss of, expression of MS4A family proteins has been observed in colon and lung cancer. However, the precise functions of MS4A family proteins and their mechanistic interactions remain unsolved. Here we report that MS4A4 facilitates trafficking of the receptor tyrosine kinase KIT through endocytic recycling rather than degradation pathways by a mechanism that involves recruitment of KIT to caveolin-1–enriched microdo...

  16. Synaptically Released Matrix Metalloproteinase Activity in Control of Structural Plasticity and the Cell Surface Distribution of GluA1-AMPA Receptors

    OpenAIRE

    Zsuzsanna Szepesi; Eric Hosy; Blazej Ruszczycki; Monika Bijata; Marta Pyskaty; Arthur Bikbaev; Martin Heine; Daniel Choquet; Leszek Kaczmarek; Jakub Wlodarczyk

    2014-01-01

    Synapses are particularly prone to dynamic alterations and thus play a major role in neuronal plasticity. Dynamic excitatory synapses are located at the membranous neuronal protrusions called dendritic spines. The ability to change synaptic connections involves both alterations at the morphological level and changes in postsynaptic receptor composition. We report that endogenous matrix metalloproteinase (MMP) activity promotes the structural and functional plasticity of local synapses by its ...

  17. 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...... of PhTX-343 were replaced by methylenes, was more potent than PhTX-343 (IC(50)=0.93 microM at -100 mV). Truncated analogues of PhTX-343 were less potent. Inhibition by all analogues was voltage-dependent. PhTX-343 (IC(50)=2.01 microM at -80 mV) was the most potent inhibitor of NMDAR. At AMPAR, most...... analogues were equipotent with PhTX-343 (IC(50)=0.46 microM at -80 mV), apart from PhTX-83, which was more potent (IC(50)=0.032 microM at -80 mV), and PhTX-(12) and 4,9-dioxa-PhTX-(12), which were less potent (IC(50)s>300 microM at -80 mV). These studies show that PhTX-(12) is a selective nAChR inhibitor...

  18. Human Trafficking

    Science.gov (United States)

    ... women and children, are exploited for purposes of prostitution and pornography. However, trafficking also takes place in ... service industry jobs overseas, but be forced into prostitution once they arrive at their destination. Coercion can ...

  19. Involvement of β3A Subunit of Adaptor Protein-3 in Intracellular Trafficking of Receptor-like Protein Tyrosine Phosphatase PCP-2

    Institute of Scientific and Technical Information of China (English)

    Hui DONG; Hong YUAN; Weirong JIN; Yan SHEN; Xiaojing XU; Hongyang WANG

    2007-01-01

    PCP-2 is a human receptor-like protein tyrosine phosphatase and a member of the MAM domain family cloned in human pancreatic adenocarcinoma cells. Previous studies showed that PCP-2 directly interacted with β-catenin through the juxtamembrane domain, dephosphorylated β-catenin and played an important role in the regulation of cell adhesion. Recent study showed that PCP-2 was also involved in the repression of β-catenin-induced transcriptional activity. Here we describe the interactions of PCP-2 with the β3A subunit of adaptor protein (AP)-3 and sorting nexin (SNX) 3. These protein complexes were detected using the yeast two-hybrid assay with the juxtamembrane and membrane-proximal catalytic domain of PCP-2 as "bait". Both AP-3 and SNX3 are molecules involved in intracellular trafficking of membrane receptors. The association between the β3A subunit of AP-3 and PCP-2 was further confirmed in mammalian cells. Our results suggested a possible mechanism of intracellular trafficking of PCP-2 mediated by AP-3 and SNX3 which might participate in the regulation of PCP-2 functions.

  20. AP1S3 mutations are associated with pustular psoriasis and impaired Toll-like receptor 3 trafficking

    NARCIS (Netherlands)

    Setta-Kaffetzi, N.; Simpson, M.A.; Navarini, A.A.; Patel, V.M.; Lu, H.C.; Allen, M.H.; Duckworth, M.; Bachelez, H.; Burden, A.D.; Choon, S.E.; Griffiths, C.E.; Kirby, B.; Kolios, A.; Seyger, M.M.B.; Prins, C.; Smahi, A.; Trembath, R.C.; Fraternali, F.; Smith, C.H.; Barker, J.N.; Capon, F.

    2014-01-01

    Adaptor protein complex 1 (AP-1) is an evolutionary conserved heterotetramer that promotes vesicular trafficking between the trans-Golgi network and the endosomes. The knockout of most murine AP-1 complex subunits is embryonically lethal, so the identification of human disease-associated alleles has

  1. The AMPA receptor subunit GluR-B in its Q/R site-unedited form is not essential for brain development and function

    OpenAIRE

    Kask, Kalev; Zamanillo, Daniel; Rozov, Andrei; Burnashev, Nail; Sprengel, Rolf; Seeburg, Peter H.

    1998-01-01

    Calcium permeability of l-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) in excitatory neurons of the mammalian brain is prevented by coassembly of the GluR-B subunit, which carries an arginine (R) residue at a critical site of the channel pore. The codon for this arginine is created by site-selective adenosine deamination of an exonic glutamine (Q) codon at the pre-mRNA level. Thus, central neurons can potentially control the calcium permeability of AMPARs by the level o...

  2. How Ca2+-permeable AMPA receptors, the kinase PKA, and the phosphatase PP2B are intertwined in synaptic LTP and LTD.

    Science.gov (United States)

    Hell, Johannes W

    2016-04-26

    Both synaptic long-term potentiation (LTP) and long-term depression (LTD) are thought to be critical for memory formation. Dell'Acqua and co-workers now demonstrate that transient postsynaptic incorporation of Ca(2+)-permeable (CP) α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) is required for LTD in the exemplary hippocampal CA1 region in 2-week-old mice. Mechanistically, LTD depends on AKAP150-anchored protein kinase A (PKA) to promote the initial functional recruitment of CP-AMPARs during LTD induction and on AKAP150-anchored protein phosphatase 2B (PP2B) to trigger their subsequent removal as part of the lasting depression of synaptic transmission.

  3. Nuclear respiratory factor 1 co-regulates AMPA glutamate receptor subunit 2 and cytochrome c oxidase: tight coupling of glutamatergic transmission and energy metabolism in neurons.

    Science.gov (United States)

    Dhar, Shilpa S; Liang, Huan Ling; Wong-Riley, Margaret T T

    2009-03-01

    Neuronal activity, especially of the excitatory glutamatergic type, is highly dependent on energy from the oxidative pathway. We hypothesized that the coupling existed at the transcriptional level by having the same transcription factor to regulate a marker of energy metabolism, cytochrome c oxidase (COX) and an important subunit of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors, GluR2 (Gria2). Nuclear respiratory factor 1 (NRF-1) was a viable candidate because it regulates all COX subunits and potentially activates Gria2. By means of in silico analysis, electrophoretic mobility shift and supershift, chromatin immunoprecipitation, and promoter mutational assays, we found that NRF-1 functionally bound to Gria2 promoter. Silencing of NRF-1 with small interference RNA prevented the depolarization-stimulated up-regulation of Gria2 and COX, and over-expression of NRF-1 rescued neurons from tetrodotoxin-induced down-regulation of Gria2 and COX transcripts. Thus, neuronal activity and energy metabolism are tightly coupled at the molecular level, and NRF-1 is a critical agent in this process.

  4. Persistent inflammation-induced up-regulation of brain-derived neurotrophic factor (BDNF) promotes synaptic delivery of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor GluA1 subunits in descending pain modulatory circuits.

    Science.gov (United States)

    Tao, Wenjuan; Chen, Quan; Zhou, Wenjie; Wang, Yunping; Wang, Lu; Zhang, Zhi

    2014-08-01

    The enhanced AMPA receptor phosphorylation at GluA1 serine 831 sites in the central pain-modulating system plays a pivotal role in descending pain facilitation after inflammation, but the underlying mechanisms remain unclear. We show here that, in the rat brain stem, in the nucleus raphe magnus, which is a critical relay in the descending pain-modulating system of the brain, persistent inflammatory pain induced by complete Freund adjuvant (CFA) can enhance AMPA receptor-mediated excitatory postsynaptic currents and the GluA2-lacking AMPA receptor-mediated rectification index. Western blot analysis showed an increase in GluA1 phosphorylation at Ser-831 but not at Ser-845. This was accompanied by an increase in distribution of the synaptic GluA1 subunit. In parallel, the level of histone H3 acetylation at bdnf gene promoter regions was reduced significantly 3 days after CFA injection, as indicated by ChIP assays. This was correlated with an increase in BDNF mRNA levels and BDNF protein levels. Sequestering endogenous extracellular BDNF with TrkB-IgG in the nucleus raphe magnus decreased AMPA receptor-mediated synaptic transmission and GluA1 phosphorylation at Ser-831 3 days after CFA injection. Under the same conditions, blockade of TrkB receptor functions, phospholipase C, or PKC impaired GluA1 phosphorylation at Ser-831 and decreased excitatory postsynaptic currents mediated by GluA2-lacking AMPA receptors. Taken together, these results suggest that epigenetic up-regulation of BDNF by peripheral inflammation induces GluR1 phosphorylation at Ser-831 sites through activation of the phospholipase C-PKC signaling cascade, leading to the trafficking of GluA1 to pain-modulating neuronal synapses.

  5. The Viral G Protein-Coupled Receptor ORF74 Hijacks β-Arrestins for Endocytic Trafficking in Response to Human Chemokines.

    Science.gov (United States)

    de Munnik, Sabrina M; Kooistra, Albert J; van Offenbeek, Jody; Nijmeijer, Saskia; de Graaf, Chris; Smit, Martine J; Leurs, Rob; Vischer, Henry F

    2015-01-01

    Kaposi's sarcoma-associated herpesvirus-infected cells express the virally encoded G protein-coupled receptor ORF74. Although ORF74 is constitutively active, it binds human CXC chemokines that modulate this basal activity. ORF74-induced signaling has been demonstrated to underlie the development of the angioproliferative tumor Kaposi's sarcoma. Whereas G protein-dependent signaling of ORF74 has been the subject of several studies, the interaction of this viral GPCR with β-arrestins has hitherto not been investigated. Bioluminescence resonance energy transfer experiments demonstrate that ORF74 recruits β-arrestins and subsequently internalizes in response to human CXCL1 and CXCL8, but not CXCL10. Internalized ORF74 traffics via early endosomes to recycling and late endosomes. Site-directed mutagenesis and homology modeling identified four serine and threonine residues at the distal end of the intracellular carboxyl-terminal of ORF74 that are required for β-arrestin recruitment and subsequent endocytic trafficking. Hijacking of the human endocytic trafficking machinery is a previously unrecognized action of ORF74.

  6. TIM-1 glycoprotein binds the adhesion receptor P-selectin and mediates T cell trafficking during inflammation and autoimmunity.

    Science.gov (United States)

    Angiari, Stefano; Donnarumma, Tiziano; Rossi, Barbara; Dusi, Silvia; Pietronigro, Enrica; Zenaro, Elena; Della Bianca, Vittorina; Toffali, Lara; Piacentino, Gennj; Budui, Simona; Rennert, Paul; Xiao, Sheng; Laudanna, Carlo; Casasnovas, Jose M; Kuchroo, Vijay K; Constantin, Gabriela

    2014-04-17

    Selectins play a central role in leukocyte trafficking by mediating tethering and rolling on vascular surfaces. Here we have reported that T cell immunoglobulin and mucin domain 1 (TIM-1) is a P-selectin ligand. We have shown that human and murine TIM-1 binds to P-selectin, and that TIM-1 mediates tethering and rolling of T helper 1 (Th1) and Th17, but not Th2 and regulatory T cells on P-selectin. Th1 and Th17 cells lacking the TIM-1 mucin domain showed reduced rolling in thrombin-activated mesenteric venules and inflamed brain microcirculation. Inhibition of TIM-1 had no effect on naive T cell homing, but it reduced T cell recruitment in a skin hypersensitivity model and blocked experimental autoimmune encephalomyelitis. Uniquely, the TIM-1 immunoglobulin variable domain was also required for P-selectin binding. Our data demonstrate that TIM-1 is a major P-selectin ligand with a specialized role in T cell trafficking during inflammatory responses and the induction of autoimmune disease.

  7. Synapse geometry and receptor dynamics modulate synaptic strength.

    Directory of Open Access Journals (Sweden)

    Dominik Freche

    Full Text Available Synaptic transmission relies on several processes, such as the location of a released vesicle, the number and type of receptors, trafficking between the postsynaptic density (PSD and extrasynaptic compartment, as well as the synapse organization. To study the impact of these parameters on excitatory synaptic transmission, we present a computational model for the fast AMPA-receptor mediated synaptic current. We show that in addition to the vesicular release probability, due to variations in their release locations and the AMPAR distribution, the postsynaptic current amplitude has a large variance, making a synapse an intrinsic unreliable device. We use our model to examine our experimental data recorded from CA1 mice hippocampal slices to study the differences between mEPSC and evoked EPSC variance. The synaptic current but not the coefficient of variation is maximal when the active zone where vesicles are released is apposed to the PSD. Moreover, we find that for certain type of synapses, receptor trafficking can affect the magnitude of synaptic depression. Finally, we demonstrate that perisynaptic microdomains located outside the PSD impacts synaptic transmission by regulating the number of desensitized receptors and their trafficking to the PSD. We conclude that geometrical modifications, reorganization of the PSD or perisynaptic microdomains modulate synaptic strength, as the mechanisms underlying long-term plasticity.

  8. 7-Chloro-5-(furan-3-yl)-3-methyl-4H-benzo[e][1,2,4]thiadiazine 1,1-Dioxide as Positive Allosteric Modulator of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptor. The End of the Unsaturated-Inactive Paradigm?

    Science.gov (United States)

    Citti, Cinzia; Battisti, Umberto M; Cannazza, Giuseppe; Jozwiak, Krzysztof; Stasiak, Natalia; Puja, Giulia; Ravazzini, Federica; Ciccarella, Giuseppe; Braghiroli, Daniela; Parenti, Carlo; Troisi, Luigino; Zoli, Michele

    2016-02-17

    5-Arylbenzothiadiazine type compounds acting as positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-PAMs) have received particular attention in the past decade for their nootropic activity and lack of the excitotoxic side effects of direct agonists. Recently, our research group has published the synthesis and biological activity of 7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (1), one of the most active benzothiadiazine-derived AMPA-PAMs in vitro to date. However, 1 exists as two stereolabile enantiomers, which rapidly racemize in physiological conditions, and only one isomer is responsible for the pharmacological activity. In the present work, experiments carried out with rat liver microsomes show that 1 is converted by hepatic cytochrome P450 to the corresponding unsaturated derivative 2 and to the corresponding pharmacologically inactive benzenesulfonamide 3. Surprisingly, patch-clamp experiments reveal that 2 displays an activity comparable to that of the parent compound. Molecular modeling studies were performed to rationalize these results. Furthermore, mice cerebral microdialysis studies suggest that 2 is able to cross the blood-brain barrier and increases acetylcholine and serotonin levels in the hippocampus. The experimental data disclose that the achiral hepatic metabolite 2 possesses the same pharmacological activity of its parent compound 1 but with an enhanced chemical and stereochemical stability, as well as an improved pharmacokinetic profile compared with 1. PMID:26580317

  9. Plectin regulates the signaling and trafficking of the HIV-1 co-receptor CXCR4 and plays a role in HIV-1 infection

    International Nuclear Information System (INIS)

    The CXC chemokine CXCL12 and its cognate receptor CXCR4 play an important role in inflammation, human immunodeficiency virus (HIV) infection and cancer metastasis. The signal transduction and intracellular trafficking of CXCR4 are involved in these functions, but the underlying mechanisms remain incompletely understood. In the present study, we demonstrated that the CXCR4 formed a complex with the cytolinker protein plectin in a ligand-dependent manner in HEK293 cells stably expressing CXCR4. The glutathione-S-transferase (GST)-CXCR4 C-terminal fusion proteins co-precipitated with the full-length and the N-terminal fragments of plectin isoform 1 but not with the N-terminal deletion mutants of plectin isoform 1, thereby suggesting an interaction between the N-terminus of plectin and the C-terminus of CXCR4. This interaction was confirmed by confocal microscopic reconstructions showing co-distribution of these two proteins in the internal vesicles after ligand-induced internalization of CXCR4 in HEK293 cells stably expressing CXCR4. Knockdown of plectin with RNA interference (RNAi) significantly inhibited ligand-dependent CXCR4 internalization and attenuated CXCR4-mediated intracellular calcium mobilization and activation of extracellular signal regulated kinase 1/2 (ERK1/2). CXCL12-induced chemotaxis of HEK293 cells stably expressing CXCR4 and of Jurkat T cells was inhibited by the plectin RNAi. Moreover, CXCR4 tropic HIV-1 infection in MAGI (HeLa-CD4-LTR-Gal) cells was inhibited by the RNAi of plectin. Thus, plectin appears to interact with CXCR4 and plays an important role in CXCR4 signaling and trafficking and HIV-1 infection

  10. 高半胱氨酸对慢性应激性抑郁大鼠海马谷氨酸及其受体的调节%Modulation of hippocampal glutamate and NMDA/AMPA receptor by homocysteine in chronic unpredictable mild stress-induced rat depression

    Institute of Scientific and Technical Information of China (English)

    刘慧; 问黎敏; 乔卉; 安书成

    2013-01-01

    The study was to investigate the role of homocysteine (Hey) which was released by hippocampal glial cells and its relationship with NMDA receptor and AMPA receptor in depression induced by chronic unpredictable mild stress (CUMS), and explore the mechanism of changes of Glu/Glu receptor in glial cells and neurons. CUMS-induced depression model was established. The body weight of rats was weighed on the 1st, 7th, 14th, and 21st days during the experiment. The behavioral performances were observed by means of sucrose consumption test, open field test and tail suspension test. Intrahippocampal microinjection of Hcy, NMDA receptor antagonist MK-801 and AMPA receptor antagonist NBQX was performed under stereotaxic guide cannula. The concentration of Glu and the expression of its receptors' subunits were detected respectively by high performance liquid chromatography (HPLC) and Western blot. The Hey content and the levels of phosphorylation of NMDA receptor and AMPA receptor in hippocampus were separately determined by enzyme linked immunosorbent assay (ELISA). The results showed that CUMS significantly induced the depression-like behaviors in rats, and the content of Glu and Hcy, the expression of NMDA receptors' subunits NR1/NR2B and the level of phosphorylation of NMDA receptor (p-NMDAR) in hippocampus increased significantly, while the expression of AMPA receptors' subunits GluR2/3 and the level of phosphorylation of AMPA receptor (p-AMPAR) decreased significantly. Microinjection of Hcy into hippocampus resulted in similar animal depression-like behaviors and increased Glu content compared to the CON/SAL group, the expression of NRl/NR2B/GluR2/3 and the level of p-NMDAR increased significantly, but the level of p-AMPAR reduced observably. Intrahippocampal injections of MK-801 effectively improved the depression-like behaviors induced by CUMS and Hcy, and attenuated the elevation of Glu content induced by Hcy in hippocampus, whereas NBQX could not improve the

  11. Ly6h regulates trafficking of alpha7 nicotinic acetylcholine receptors and nicotine-induced potentiation of glutamatergic signaling.

    Science.gov (United States)

    Puddifoot, Clare A; Wu, Meilin; Sung, Rou-Jia; Joiner, William J

    2015-02-25

    α7 nAChRs are expressed widely throughout the brain, where they are important for synaptic signaling, gene transcription, and plastic changes that regulate sensory processing, cognition, and neural responses to chronic nicotine exposure. However, the mechanisms by which α7 nAChRs are regulated are poorly understood. Here we show that trafficking of α7-subunits is controlled by endogenous membrane-associated prototoxins in the Ly6 family. In particular, we find that Ly6h reduces cell-surface expression and calcium signaling by α7 nAChRs. We detect Ly6h in several rat brain regions, including the hippocampus, where we find it is both necessary and sufficient to limit the magnitude of α7-mediated currents. Consistent with such a regulatory function, knockdown of Ly6h in rat hippocampal pyramidal neurons enhances nicotine-induced potentiation of glutamatergic mEPSC amplitude, which is known to be mediated by α7 signaling. Collectively our data suggest a novel cellular role for Ly6 proteins in regulating nAChRs, which may be relevant to plastic changes in the nervous system including rewiring of glutamatergic circuitry during nicotine addiction. PMID:25716842

  12. Economics of human trafficking.

    Science.gov (United States)

    Wheaton, Elizabeth M; Schauer, Edward J; Galli, Thomas V

    2010-01-01

    Because freedom of choice and economic gain are at the heart of productivity, human trafficking impedes national and international economic growth. Within the next 10 years, crime experts expect human trafficking to surpass drug and arms trafficking in its incidence, cost to human well-being, and profitability to criminals (Schauer and Wheaton, 2006: 164-165). The loss of agency from human trafficking as well as from modern slavery is the result of human vulnerability (Bales, 2000: 15). As people become vulnerable to exploitation and businesses continually seek the lowest-cost labour sources, trafficking human beings generates profit and a market for human trafficking is created. This paper presents an economic model of human trafficking that encompasses all known economic factors that affect human trafficking both across and within national borders. We envision human trafficking as a monopolistically competitive industry in which traffickers act as intermediaries between vulnerable individuals and employers by supplying differentiated products to employers. In the human trafficking market, the consumers are employers of trafficked labour and the products are human beings. Using a rational-choice framework of human trafficking we explain the social situations that shape relocation and working decisions of vulnerable populations leading to human trafficking, the impetus for being a trafficker, and the decisions by employers of trafficked individuals. The goal of this paper is to provide a common ground upon which policymakers and researchers can collaborate to decrease the incidence of trafficking in humans.

  13. Deletion of the NMDA-NR1 receptor subunit gene in the mouse nucleus accumbens attenuates apomorphine-induced dopamine D1 receptor trafficking and acoustic startle behavior

    OpenAIRE

    Glass, Michael J.; Robinson, Danielle C.; Waters, Elizabeth; Pickel, Virginia M.

    2013-01-01

    The nucleus accumbens (Acb) contains subpopulations of neurons defined by their receptor content and potential involvement in sensorimotor gating and other behaviors that are dysfunctional in schizophrenia. In Acb neurons, the NMDA NR1 (NR1) subunit is co-expressed not only with the dopamine D1 receptor (D1R), but also with the μ-opioid receptor (μ-OR), which mediates certain behaviors that are adversely impacted by schizophrenia. The NMDA-NR1 subunit has been suggested to play a role in the ...

  14. 钩藤碱对甲基苯丙胺条件性位置偏爱大鼠AMPA受体蛋白改变的影响%The effect of rhynchophylline on AMPA receptors expression in methamphetamine dependent rats

    Institute of Scientific and Technical Information of China (English)

    林晓亮; 汤伟; 陈文倩; 翁建霖; 莫志贤

    2010-01-01

    Objective To study changes of AMPA receptors expression in nucleus accumbens and hypothalamus of methamphetamine dependent rats,and the therapeutical effect of rhynchophylline.Methods SPF male rata were randomly divided into normal control group,model group of methamphetamine,low dose of rhynchophylline group and high dose of rhynchophylline group(n=8 in each group).Experiment of conditioned place preference(CPP)was used to build the model of methamphetamine dependent rata.Western blotting was used to examine the changes of GluR2/3 subunits expression.The time of staying in drug-paired compartment of rats was used independent-samples t test to gather statistics,and the photodensity of proteinum strap was used One-Way ANOVA to gather statistics.Results Compare with rats in normal control group(the time of staying in drug-paired compartment of rats was(383.00±38.20)s),the rats produced CPP after treated with methamphetamine(the time of staying in drug-paired compartment of rats was(536.20±57.49)s),and low(30mg/kg) and high (60 ms/kg)dose of rhynchophylline(the time of staying in drug-paired compartment of rats were(299.80±15.96)s and(189.40±59.02)s)both could eliminate CPP effect.Compare with rats in normal control group (the ratio of value of average gray scale were(0.54±0.04)INT·mm~2 and (0.70±0.04)INT·mm~2),GluR2/3 subunits expression in nucleus aecumbens increased significantly in model group(the ratio of value of average gray seale was(0.89±0.03)INT·mm~2)and low dose of rhynchophylline group(the ratio of value of average gray seale was (0.93±0.03)INT·mm~2,P0.05).Conclusion GluR2/3 subunits expression of methamphetamine-induced CPP rats increased in nucleus accumbens but decreased in hypothalamus.High dose of rhynchophylline can reverse such changes and rebound the expression to normal level.%目的 观察甲基苯丙胺成瘾大鼠伏隔核及下丘脑中AMPA受体表达的改变及钩藤碱对其的干预作用.方法 SPF级雄性SD大鼠分为空

  15. Palmitoylation regulates intracellular trafficking of β2 adrenergic receptor/arrestin/phosphodiesterase 4D complexes in cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Ruijie Liu

    Full Text Available β(2 adrenergic receptor (β(2AR is a prototypical G-protein coupled receptor that stimulates the classic cAMP-protein kinase A (PKA signaling pathway. Recent studies indicate that the cAMP-PKA activities are spatiotemporally regulated in part due to dynamic association of β(2AR with phosphodiesterase 4D (PDE4D, a group of cAMP degradation enzymes. Here, we demonstrate that in cardiomyocytes, palmitoylation of β(2AR, the covalent acylation of cysteine residue 341, plays a critical role in shaping subcellular cAMP-PKA activities in cardiomyocytes via regulating β(2AR association with arrestin/PDE4D. Replacing cysteine 341 on β(2AR with alanine (C341A leads to an impaired binding to β arrestin 2. Surprisingly, the C341A mutant is able to internalize via an arrestin-independent pathway at saturated concentration of agonist stimulation; the internalization becomes caveolae-dependent and requires dynamin GTPase. However, the impaired binding to β arrestin 2 also leads to an impaired recruitment of PDE4D to the C341A mutant. Thus, the mutant C341A β(2AR is transported alone from the plasma membrane to the endosome without recruiting PDE4D. This alteration leads to an enhanced cytoplasmic cAMP signal for PKA activation under β(2AR stimulation. Functionally, Mutation of the C341 residue or inhibition of palmitoylation modification of β(2AR enhances the receptor-induced PKA activities in the cytoplasm and increases in myocyte contraction rate. Our data reveal a novel function of palmitoylation in shaping subcellular cAMP-PKA signaling in cardiomyocytes via modulating the recruitment of β arrestin 2-PDE4D complexes to the agonist-stimulated β(2AR.

  16. Prolonged adenosine A1 receptor activation in hypoxia and pial vessel disruption focal cortical ischemia facilitates clathrin-mediated AMPA receptor endocytosis and long-lasting synaptic inhibition in rat hippocampal CA3-CA1 synapses: differential regulation of GluA2 and GluA1 subunits by p38 MAPK and JNK.

    Science.gov (United States)

    Chen, Zhicheng; Xiong, Cherry; Pancyr, Cassandra; Stockwell, Jocelyn; Walz, Wolfgang; Cayabyab, Francisco S

    2014-07-16

    Activation of presynaptic adenosine A1 receptors (A1Rs) causes substantial synaptic depression during hypoxia/cerebral ischemia, but postsynaptic actions of A1Rs are less clear. We found that A1Rs and GluA2-containing AMPA receptors (AMPARs) form stable protein complexes from hippocampal brain homogenates and cultured hippocampal neurons from Sprague Dawley rats. In contrast, adenosine A2A receptors (A2ARs) did not coprecipitate or colocalize with GluA2-containing AMPARs. Prolonged stimulation of A1Rs with the agonist N(6)-cyclopentyladenosine (CPA) caused adenosine-induced persistent synaptic depression (APSD) in hippocampal brain slices, and APSD levels were blunted by inhibiting clathrin-mediated endocytosis of GluA2 subunits with the Tat-GluA2-3Y peptide. Using biotinylation and membrane fractionation assays, prolonged CPA incubation showed significant depletion of GluA2/GluA1 surface expression from hippocampal brain slices and cultured neurons. Tat-GluA2-3Y peptide or dynamin inhibitor Dynasore prevented CPA-induced GluA2/GluA1 internalization. Confocal imaging analysis confirmed that functional A1Rs, but not A2ARs, are required for clathrin-mediated AMPAR endocytosis in hippocampal neurons. Pharmacological inhibitors or shRNA knockdown of p38 MAPK and JNK prevented A1R-mediated internalization of GluA2 but not GluA1 subunits. Tat-GluA2-3Y peptide or A1R antagonist 8-cyclopentyl-1,3-dipropylxanthine also prevented hypoxia-mediated GluA2/GluA1 internalization. Finally, in a pial vessel disruption cortical stroke model, a unilateral cortical lesion compared with sham surgery reduced hippocampal GluA2, GluA1, and A1R surface expression and also caused synaptic depression in hippocampal slices that was consistent with AMPAR downregulation and decreased probability of transmitter release. Together, these results indicate a previously unknown mechanism for A1R-induced persistent synaptic depression involving clathrin-mediated GluA2 and GluA1 internalization that

  17. Mechanisms Underlying Activation of α1-Adrenergic Receptor-Induced Trafficking of AQP5 in Rat Parotid Acinar Cells under Isotonic or Hypotonic Conditions

    Science.gov (United States)

    Bragiel, Aneta M.; Wang, Di; Pieczonka, Tomasz D.; Shono, Masayuki; Ishikawa, Yasuko

    2016-01-01

    Defective cellular trafficking of aquaporin-5 (AQP5) to the apical plasma membrane (APM) in salivary glands is associated with the loss of salivary fluid secretion. To examine mechanisms of α1-adrenoceptor (AR)-induced trafficking of AQP5, immunoconfocal microscopy and Western blot analysis were used to analyze AQP5 localization in parotid tissues stimulated with phenylephrine under different osmolality. Phenylephrine-induced trafficking of AQP5 to the APM and lateral plasma membrane (LPM) was mediated via the α1A-AR subtype, but not the α1B- and α1D-AR subtypes. Phenylephrine-induced trafficking of AQP5 was inhibited by ODQ and KT5823, inhibitors of nitric oxide (NO)-stimulated guanylcyclase (GC) and protein kinase (PK) G, respectively, indicating the involvement of the NO/ soluble (c) GC/PKG signaling pathway. Under isotonic conditions, phenylephrine-induced trafficking was inhibited by La3+, implying the participation of store-operated Ca2+ channel. Under hypotonic conditions, phenylephrine-induced trafficking of AQP5 to the APM was higher than that under isotonic conditions. Under non-stimulated conditions, hypotonicity-induced trafficking of AQP5 to the APM was inhibited by ruthenium red and La3+, suggesting the involvement of extracellular Ca2+ entry. Thus, α1A-AR activation induced the trafficking of AQP5 to the APM and LPM via the Ca2+/ cyclic guanosine monophosphate (cGMP)/PKG signaling pathway, which is associated with store-operated Ca2+ entry. PMID:27367668

  18. 短时重复游泳调节SAM8鼠AMPA受体GluR1亚单位的磷酸化%A transient, but repeated swimming regulating the GluR1 phosphorylation of AMPA receptor in SAM8 mice

    Institute of Scientific and Technical Information of China (English)

    吕媛媛; 赵丽; 王德刚

    2012-01-01

    目的 观察短时重复游泳训练对SAM鼠AMPA受体GluR1亚单位磷酸化的影响,探讨运动改善脑功能的可能机制.方法 选取3月龄SAMP8(prone/8)亚系为研究对象,运动模型采用2w游泳方案:2次/d,每次6min的游泳,结束后给予浴巾擦干放回鼠笼;对照组则在相同时间每天给予两次相同的浴巾安抚刺激.采用Western印迹方法,检测SAM8鼠海马和皮层AMPA受体GluR1亚单位Ser831和Ser845位点的磷酸化水平的变化.结果 SAMP8海马、皮层中AMPA受体GluR1亚单位Ser831和Ser845磷酸化水平与对照组相比均增加(P<0.05).结论 2w的短时间重复游泳运动作为一种应激诱导剂促进了AMPA受体的活化,这可能是运动改善脑功能的机制之一.%Objective To investigate the effects of a transient, but repeated swimming on the GluRl phosphorylation of AMPA receptor in SAM8 mice, and explore the possible molecular mechanisms for exercise improving brain function. Methods 16 male SAM8 mice were equally randomized into normal and swimming groups. Swimming protocol was conducted twice a day for 6 min, each for a total of 14 days. After swimming, the mice were dried with a towel and placed back into their original cage. A control group of animals was handled for 6 s, wrapped in a towel twice a day for 14 days to simulate the handle after swimming. The phosphorylation of GluRl at Ser831 and Ser845 were measured by Western blot. Results Compared with normal group, both in cortex and in hippocampus, the phosphorylation degree of GluRl at Ser831 and Ser845 were significantly increased (all P <0. 01). Conclusions 2-week swimming protocol may be a stress inducer which lead to the activation of AMPA receptor, and that may be the one of mechanisms of exercise benefiting brain function.

  19. Trafficking in Greece

    OpenAIRE

    Lymouris, Nikolaos

    2007-01-01

    Trafficking in human beings has taken on great proportions worldwide over the last twenty years. “Traditional” slave trade and slavery have evolved into a “modern” business, especially under the forms of compulsory labour and sexual exploitation. It is estimated that trafficking in human beings constitutes the third largest “criminal business” after illicit trafficking of narcotics and arms.

  20. Hook-up of GluA2, GRIP and liprin-α for cholinergic muscarinic receptor-dependent LTD in the hippocampus

    Directory of Open Access Journals (Sweden)

    Wu Long-Jun

    2009-06-01

    Full Text Available Abstract The molecular mechanism underlying muscarinic acetylcholine receptor-dependent LTD (mAChR-LTD in the hippocampus is less studied. In a recent study, a novel mechanism is described. The induction of mAChR-LTD required the activation of protein tyrosine phosphatase (PTP, and the expression was mediated by AMPA receptor endocytosis via interactions between GluA2, GRIP and liprin-α. The hook-up of these proteins may result in the recruitment of leukocyte common antigen-related receptor (LAR, a PTP that is known to be involved in AMPA receptor trafficking. Interestingly, the similar molecular interaction cannot be applied to mGluR-LTD, despite the fact that the same G-protein involved in LTD is activated by both mAChR and mGluR. This discovery provides key molecular insights for cholinergic dependent cognitive function, and mAChR-LTD can serve as a useful cellular model for studying the roles of cholinergic mechanism in learning and memory.

  1. Molecular nuclear imaging for targeting and trafficking

    International Nuclear Information System (INIS)

    Progress of molecular biology, genetic engineering, and polymer chemistry provide various tools to target molecules and cells in vivo. In this paper, recent achievements in targeting receptors for hepatocyte or inflammatory cells and in trafficking bacterial, immune, and stem cells using molecular nuclear imaging techniques are introduced

  2. Smuggled or trafficked?

    Directory of Open Access Journals (Sweden)

    Jacqueline Bhabha

    2006-05-01

    Full Text Available The UN Convention Against Transnational Organized Crime (TNC and its two Protocols on Trafficking and Smuggling, adopted in 2000, seek to distinguish between trafficking and smuggling. In reality these distinctions are often blurred. A more nuanced approach is needed to ensure protection for all those at risk.

  3. Excitotoxic effects of non-NMDA receptor agonists in organotypic corticostriatal slice cultures

    DEFF Research Database (Denmark)

    Kristensen, B W; Noraberg, J; Jakobsen, B;

    1999-01-01

    The excitotoxic effects of the glutamate receptor agonists kainic acid (KA) and 2-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and the corresponding neuroprotective effects of the AMPA/KA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX) were examined...

  4. Human trafficking and regulating prostitution

    OpenAIRE

    Lee, Samuel; Persson, Petra

    2013-01-01

    We study sex trafficking in a marriage market model of prostitution. When traffickers can coerce women to sell sex, trafficked prostitutes constitute a non-zero share of supply in any unregulated market for sex. We ask if regulation can eradicate trafficking and restore the equilibrium that would arise in an unregulated market without traffickers. While all existing approaches – criminalization of prostitutes (“the traditional model”), licensed prostitution (“the Dutch model”), and criminaliz...

  5. 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

    .1+/-2.9. The pharmacological profiles of these receptors resembled that of native rat brain AMPA receptors: AMPA analogues > L-glutamate > quinoxaline-2,3-diones > kainate. In the Xenopus oocyte expression system we had previously shown that the agonist (R,S)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionate (ACPA...

  6. LRP-1 and LRP-2 receptors function in the membrane neuron. Trafficking mechanisms and proteolytic processing in Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Carlos eSpuch

    2012-07-01

    Full Text Available Low density lipoprotein receptor-related protein (LRP belongs to the low-density lipoprotein receptor family, generally recognized as cell surface endocytic receptors, which bind and internalize extracellular ligands for degradation in lysosomes. Neurons require cholesterol to function and keep the membrane rafts stable. Cholesterol uptake into the neuron is carried out by ApoE via LRPs receptors on the cell surface. In neurons the most important are LRP-1 and LRP-2, even it is thought that a causal factor in Alzheimer’s disease (AD is the malfunction of this process which cause impairment intracellular signalling as well as storage and/or release of nutrients and toxic compounds. Both receptors are multifunctional cell surface receptors that are widely expressed in several tissues including neurons and astrocytes. LRPs are constituted by an intracellular (ICD and extracellular domain (ECD. Through its ECD, LRPs bind at least 40 different ligands ranging from lipoprotein and protease inhibitor complex to growth factors and extracellular matrix proteins. These receptors has also been shown to interact with scaffolding and signalling proteins via its ICD in a phosphorylation-dependent manner and to function as a co-receptor partnering with other cell surface or integral membrane proteins. Thus, LRPs are implicated in two major physiological processes: endocytosis and regulation of signalling pathways, which are both involved in diverse biological roles including lipid metabolism, cell growth processes, degradation of proteases, and tissue invasion. Interestingly, LRPs were also localized in neurons in different stages, suggesting that both receptors could be implicated in signal transduction during embryonic development, neuronal outgrowth or in the pathogenesis of AD

  7. Cell Signaling and Trafficking of Human Melanocortin Receptors in Real Time Using Two-photon Fluorescence and Confocal Laser Microscopy: Differentiation of Agonists and Antagonists

    OpenAIRE

    Cai, Minying; Varga, Eva V.; Stankova, Magda; Mayorov, Alexander; Perry, Joseph W.; Yamamura, Henry I.; Trivedi, Dev; Victor J. Hruby

    2006-01-01

    Melanocortin hormones and neurotransmitters regulate a vast array of physiologic processes by interacting with five G-protein-coupled melanocortin receptor types. In the present study, we have systematically studied the regulation of individual human melanocortin receptor wild subtypes using a synthetic rhodamine-labeled human melanotropin agonist and antagonist, arrestins fused to green fluorescent protein in conjunction with two-photon fluorescence laser scanning microscopy and confocal mic...

  8. Protein trafficking during plant innate immunity

    Institute of Scientific and Technical Information of China (English)

    Wen-Ming Wang; Peng-Qiang Liu; Yong-Ju Xu; Shunyuan Xiao

    2016-01-01

    Plants have evolved a sophisticated immune system to fight against pathogenic microbes. Upon detection of pathogen invasion by immune receptors, the immune system is turned on, resulting in production of antimicrobial molecules including pathogenesis-related (PR) proteins. Conceivably, an efficient immune response depends on the capacity of the plant cell’s protein/membrane trafficking network to deploy the right defense-associated molecules in the right place at the right time. Recent research in this area shows that while the abundance of cell surface immune receptors is regulated by endocytosis, many intracellular immune receptors, when activated, are partitioned between the cytoplasm and the nucleus for induction of defense genes and activation of programmed cell death, respectively. Vesicle transport is an essential process for secretion of PR proteins to the apoplastic space and targeting of defense-related proteins to the plasma membrane or other endomembrane compartments. In this review, we discuss the various aspects of protein trafficking during plant immunity, with a focus on the immunity proteins on the move and the major compo-nents of the trafficking machineries engaged.

  9. Protein trafficking during plant innate immunity.

    Science.gov (United States)

    Wang, Wen-Ming; Liu, Peng-Qiang; Xu, Yong-Ju; Xiao, Shunyuan

    2016-04-01

    Plants have evolved a sophisticated immune system to fight against pathogenic microbes. Upon detection of pathogen invasion by immune receptors, the immune system is turned on, resulting in production of antimicrobial molecules including pathogenesis-related (PR) proteins. Conceivably, an efficient immune response depends on the capacity of the plant cell's protein/membrane trafficking network to deploy the right defense-associated molecules in the right place at the right time. Recent research in this area shows that while the abundance of cell surface immune receptors is regulated by endocytosis, many intracellular immune receptors, when activated, are partitioned between the cytoplasm and the nucleus for induction of defense genes and activation of programmed cell death, respectively. Vesicle transport is an essential process for secretion of PR proteins to the apoplastic space and targeting of defense-related proteins to the plasma membrane or other endomembrane compartments. In this review, we discuss the various aspects of protein trafficking during plant immunity, with a focus on the immunity proteins on the move and the major components of the trafficking machineries engaged. PMID:26345282

  10. Scavenger receptor class B type I (SR-BI) in pig enterocytes: trafficking from the brush border to lipid droplets during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte W; Immerdal, Lissi;

    2003-01-01

    BACKGROUND: Scavenger receptor class B type I (SR-BI) is known to mediate cellular uptake of cholesterol from high density lipoprotein particles and is particularly abundant in liver and steroidogenic tissues. In addition, SR-BI expression in the enterocyte brush border has also been reported but...... fat, SR-BI is endocytosed from the enterocyte brush border and accumulates in cytoplasmic lipid droplets. Internalisation of the receptor occurs mainly by clathrin coated pits rather than by a caveolae/lipid raft based mechanism....... fractionation. RESULTS: In the fasting state, SR-BI was mainly localised in the microvillar membrane and in apical invaginations/pits between adjacent microvilli. In addition, a subapical compartment and small cytoplasmic lipid droplets were distinctly labelled. During lipid absorption, the receptor was found...... in clathrin positive apical coated pits and vesicles. In addition, cytoplasmic lipid droplets that greatly increased in size and number were strongly labelled by the SR-BI antibody whereas apolipoprotein A-1 positive chylomicrons were largely devoid of the receptor. CONCLUSION: During absorption of dietary...

  11. Effects of Paclitaxel on EGFR Endocytic Trafficking Revealed Using Quantum Dot Tracking in Single Cells

    OpenAIRE

    Li, Hui; Duan, Zhao-Wen; Xie, Ping; Liu, Yu-Ru; Wang, Wei-Chi; Dou, Shuo-Xing; Wang, Peng-Ye

    2012-01-01

    Paclitaxel (PTX), a chemotherapeutic drug, affects microtubule dynamics and influences endocytic trafficking. However, the mechanism and the dynamics of altered endocytic trafficking by paclitaxel treatment in single living cells still remain elusive. By labeling quantum dots (QDs) to the epidermal growth factor (EGF), we continuously tracked the endocytosis and post-endocytic trafficking of EGF receptors (EGFRs) in A549 cells for a long time interval. A single-cell analysis method was introd...

  12. Human Trafficking in Nepal

    DEFF Research Database (Denmark)

    Gyawali, Bishal; Keeling, June; Kallestrup, Per

    2016-01-01

    As Nepal mourns the 1-year commemoration of the April 2015 earthquake and its aftershocks that killed more than 8500 people and left thousands injured and displaced, other more hidden repercussions of the resultant chaotic environment need attention: the increased risk of human trafficking...

  13. A novel mechanism of hippocampal LTD involving muscarinic receptor-triggered interactions between AMPARs, GRIP and liprin-α

    Directory of Open Access Journals (Sweden)

    Dickinson Bryony A

    2009-06-01

    Full Text Available Abstract Background Long-term depression (LTD in the hippocampus can be induced by activation of different types of G-protein coupled receptors, in particular metabotropic glutamate receptors (mGluRs and muscarinic acethycholine receptors (mAChRs. Since mGluRs and mAChRs activate the same G-proteins and isoforms of phospholipase C (PLC, it would be expected that these two forms of LTD utilise the same molecular mechanisms. However, we find a distinct mechanism of LTD involving GRIP and liprin-α. Results Whilst both forms of LTD require activation of tyrosine phosphatases and involve internalisation of AMPARs, they use different molecular interactions. Specifically, mAChR-LTD, but not mGluR-LTD, is blocked by peptides that inhibit the binding of GRIP to the AMPA receptor subunit GluA2 and the binding of GRIP to liprin-α. Thus, different receptors that utilise the same G-proteins can regulate AMPAR trafficking and synaptic efficacy via distinct molecular mechanisms. Conclusion Our results suggest that mAChR-LTD selectively involves interactions between GRIP and liprin-α. These data indicate a novel mechanism of synaptic plasticity in which activation of M1 receptors results in AMPAR endocytosis, via a mechanism involving interactions between GluA2, GRIP and liprin-α.

  14. Regulation of integrin trafficking, cell adhesion and cell migration by WASH and the Arp2/3 Complex

    OpenAIRE

    Duleh, Steve N.; Welch, Matthew D.

    2012-01-01

    WASH is a nucleation-promoting factor for the Arp2/3 complex that is implicated in multiple endocytic trafficking pathways including receptor recycling, cargo degradation, and retromer-mediated receptor retrieval. We sought to examine whether WASH plays an important role in trafficking of specialized cargo molecules such as integrins, for which trafficking is highly regulated during cell migration. We observed that subdomains of early/sorting endosomes associated with dynamic WASH and filamen...

  15. The relationship between the IL-1 receptor structure and its trafficking function%I型IL-1受体的结构与其转运功能相关的研究

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM:To analyze the relationship between structure and traffickingfunction of IL-1 receptor.METHODS: Wild type and mutant (W514A) IL-1 receptor cDNA containing mouse extracellular domain and human intracellular domain, IL-1 receptor cDNA only containing mouse extracellular domain, were inserted into pEGFP-N2 C-terminal protein fusion vector, respectively. All constructs were transfected respectively into human fibroblasts using calcium phosphate precipitation method. The location of expressing fusion protein at single cell level and translocation after binding with IL-1 were determined under confocal microscopy. RESULTS: The wild type IL-1 receptor located in cell membrane, extended processes and accumulated in areas suggestive of sites of focal adhesions. Further, the fusion proteins moved into cytoplasm and finally concentrate in nuclear after IL-1 stimulation. In contrast, mutant and extracellular domain IL-1 receptors did not translocate to sites of cell adhesion and were unaffected by IL-1 stimulation. CONCLUSION: Fibronectin can increase the expression of IL-1 receptor. The trafficking of IL-1 receptor is dependant on structurally intact, specific structure (tryptophan at 514) of C-terminal end of the cytoplasmic tail of the receptor is necessary.%目的:为进一步了解IL-1受体的结构与IL-1受体在细胞内表达后的转运的关系,以及该结构改变对IL-1受体功能的影响。方法:将重组型、突变型和仅含细胞外段的I型IL-1受体(IL-1RI)的质粒构建入含有绿色荧光蛋白的表达载体中,用磷酸钙沉淀法转染入成纤维细胞中,通过激光扫描共聚焦显微镜,观察其表达的融合蛋白在单个活细胞中的定位,以及与IL-1结合后的运动变化。结果:重组型IL-1RI的融合蛋白表达后主要位于细胞膜和细胞伸出的突起与细胞基质相接触的焦点附着斑处,加入IL-1后,逐渐从细胞膜上移至细胞质内,最后聚集

  16. Neuronal Early Endosomes Require EHD1 for L1/NgCAM Trafficking

    NARCIS (Netherlands)

    Lasiecka, Zofia M.; Yap, Chan Choo; Caplan, Steven; Winckler, Bettina

    2010-01-01

    In neurons, the endosomal system is essential for membrane receptor trafficking to dendrites and axons and thereby participates in various neuronal functions, such as neurite outgrowth and synaptic plasticity. A multitude of regulators coordinates trafficking through endosomes, but most of them have

  17. Theanine Depressed the Food Intake and Gastric Emptying in Female Mice via Lateral Hypothalamic AMPA and NMDA Receptor%茶氨酸经下丘脑腹外侧核抑制雌性小鼠摄食与胃排空作用研究

    Institute of Scientific and Technical Information of China (English)

    虞希冲; 杨伟; 吴波拉

    2013-01-01

    采用比色法观察脑室、核团内微注射和腹腔注射茶氨酸对外周胃排空的影响。结果表明,腹腔给予茶氨酸3~30 mg/kg后显著抑制摄食量和胃排空;脑室给药3~100 ng后,对胃排空的影响表现出V型曲线,3~30 ng茶氨酸剂量依赖性抑制胃排空,50、100 ng茶氨酸使胃排空恢复到正常水平。然而,腹腔注射同样量的茶氨酸并无抑制作用。在下丘脑外侧核内注射同量茶氨酸,出现与脑室内类似的抑制胃排空作用,在弓状核、下丘脑腹内侧核内注射却无明显的改变。在下丘脑外侧核内注射NMDA和AMPA后均能诱导摄食和胃排空的增加,而茶氨酸10、30、100 ng能抑制两者诱导的胃排空及 NMDA诱导的摄食,茶氨酸3~100 ng能抑制 AMPA诱导的摄食。上述结果表明茶氨酸抑制摄食和胃排空作用可能与抑制下丘脑外侧核的NMDA受体和AMPA受体有关。%In the present study, the food intake and gastric emptying of female mice were evaluated after theanine microinjection in cerebral ventrile, lateral hypothalamus, arcurate nuleius and ventromedial hypothalamic nucleus. Results showed that theanine 3~30 mg/kg intraperitoneal injection decreased food intake and gastric emptying;theanine 3~100 ng microinjection into cerebral ventrile induced “V” style effects on gastric, theanine 3~30 ng decreased gastric emptying dose-dependently while theanine 50 and 100 ng recovered gastric emptying. Theanine microinjection in lateral hypothalamus displayed similar effects on gastic emptying as theanine i.c.v while microinjection in arcurate nucleus and ventromedial hypothalamic nucleus did not alert gastric emptying. Theanine decreased food intake and gastric emptying induced by NMDA and AMPA microinjection in lateral hypothalamus. It was concluded that theanine depressed the food intake and gastric emptying after microinjection in lateral hypothalamus via NMDA and AMP receptor, partly.

  18. Vesicle trafficking in plant immune responses.

    Science.gov (United States)

    Robatzek, Silke

    2007-01-01

    In plants, perception of pathogen-associated molecular patterns at the surface is the first line of defence in cellular immunity. This review summarizes recent evidence of the involvement of vesicle trafficking in the plant's immune response against pathogens. I first discuss aspects of ligand-stimulated receptor endocytosis. The best-characterized pattern-recognition receptor (PRR), FLS2, is a transmembrane leucine-rich repeat receptor kinase that recognizes bacterial flagellin. FLS2 was recently shown to undergo internalization upon activation with its cognate ligand. An animal PRR, TLR4 that mediates perception of bacterial-derived lipopolysaccharides, similarly exhibits ligand-stimulated endocytosis. The second focus is N-ethylmaleimide-sensitive factor adaptor protein receptor (SNARE)-mediated immunity involving syntaxins and their cognate partners. One of the genes involved in basal immunity in Arabidopsis, PEN1, encodes a syntaxin that focally accumulates at fungal penetration sites, raising the possibility that induced exocytosis is important for active defence. Pathogen-triggered endocytic and exocytic processes have to be balanced to ensure host cell homeostasis. Thus, understanding how phytopathogens have evolved strategies to exploit host cell vesicle trafficking to manipulate immune responses is currently an area of intense study. PMID:17081192

  19. Effect of brain-derived neurotrophic factor on activity-regulated cytoskeleton-associated protein gene expression in primary frontal cortical neurons. Comparison with NMDA and AMPA.

    Science.gov (United States)

    El-Sayed, Mona; Hofman-Bang, Jacob; Mikkelsen, Jens D

    2011-06-25

    The effect of brain-derived neurotrophic factor (BDNF) on activity-regulated cytoskeleton-associated protein (Arc) mRNA levels in primary neuronal cultures of rat frontal cortex was characterized pharmacologically and compared to the effect on expression of c-fos, bdnf, neuritin, cox-2 as examples of other immediate early genes. BDNF induced a very strong increase (around 100 fold) in Arc mRNA and the maximal effect seen at 25 ng/ml. The effect was dose-dependent with EC50 around 1.6 ng/ml. The time profile revealed a significant effect after 25 min. BDNF also increased levels of c-Fos, neuritin and BDNF mRNA, but not COX-2 mRNA. The pharmacological profile of NMDA and AMPA-induced arc gene expression in frontal cortical neurons was compared to BDNF. NMDA and AMPA increased Arc mRNA but their maximal effect did not exceed 20-fold. The effect of AMPA was completely blocked by the NMDA receptor antagonist MK-801. Further, the relative amount of Arc mRNA compared to c-Fos mRNA was higher for BDNF, equal for NMDA and lower for AMPA. These results demonstrate BDNF to be a highly potent and efficient inducer of arc gene expression in vitro, emphasizing the role of this growth factor in synaptic plasticity in the frontal cortex. PMID:21515256

  20. Trafficking in human organs

    Directory of Open Access Journals (Sweden)

    Stevković Ljiljana

    2009-01-01

    Full Text Available Trafficking in human organs is a contemporary international problem that engages the attention of media more so than researchers and representatives of medical and legislative institutions. The purpose of this paper is to point out the main characteristics of this segment of organized crime, and to try to underline its seriousness and the necessity of more active prevention and suppression. This paper is divided into four thematic parts. After the introduction and terminological determination, the author gives a brief analysis of regional dimensions of trafficking in human organs. In continuation, a brief turn over of international medical and legal regulation, with concluding consideration in the final part of the paper is given.

  1. International aspects of human trafficking – Especially trafficking with minors

    OpenAIRE

    Ivanova, Elena

    2011-01-01

    Liberalization of understanding and relations, the liberation of sexuality from the constrains of primitivism and tradition, leads to rapid growth of prostitution as a socio-pathological phenomenon, which necessarily stimulate the emergence of crime - trafficking with human beings. Particularly worrying is the emergence of a new dimension of human trafficking - trafficking in minors. Children, in addition to women, in international documents, often receive the status of “spe...

  2. Combinations of physiologic estrogens with xenoestrogens alter calcium and kinase responses, prolactin release, and membrane estrogen receptor trafficking in rat pituitary cells

    Directory of Open Access Journals (Sweden)

    Watson Cheryl S

    2010-10-01

    Full Text Available Abstract Background Xenoestrogens such as alkylphenols and the structurally related plastic byproduct bisphenol A have recently been shown to act potently via nongenomic signaling pathways and the membrane version of estrogen receptor-α. Though the responses to these compounds are typically measured individually, they usually contaminate organisms that already have endogenous estrogens present. Therefore, we used quantitative medium-throughput screening assays to measure the effects of physiologic estrogens in combination with these xenoestrogens. Methods We studied the effects of low concentrations of endogenous estrogens (estradiol, estriol, and estrone at 10 pM (representing pre-development levels, and 1 nM (representing higher cycle-dependent and pregnancy levels in combinations with the same levels of xenoestrogens in GH3/B6/F10 pituitary cells. These levels of xenoestrogens represent extremely low contamination levels. We monitored calcium entry into cells using Fura-2 fluorescence imaging of single cells. Prolactin release was measured by radio-immunoassay. Extracellular-regulated kinase (1 and 2 phospho-activations and the levels of three estrogen receptors in the cell membrane (ERα, ERβ, and GPER were measured using a quantitative plate immunoassay of fixed cells either permeabilized or nonpermeabilized (respectively. Results All xenoestrogens caused responses at these concentrations, and had disruptive effects on the actions of physiologic estrogens. Xenoestrogens reduced the % of cells that responded to estradiol via calcium channel opening. They also inhibited the activation (phosphorylation of extracellular-regulated kinases at some concentrations. They either inhibited or enhanced rapid prolactin release, depending upon concentration. These latter two dose-responses were nonmonotonic, a characteristic of nongenomic estrogenic responses. Conclusions Responses mediated by endogenous estrogens representing different life stages are

  3. Health implications of human trafficking.

    Science.gov (United States)

    Richards, Tiffany A

    2014-01-01

    Freedom is arguably the most cherished right in the United States. But each year, approximately 14,500 to 17,500 women, men and children are trafficked into the United States for the purposes of forced labor or sexual exploitation. Human trafficking has significant effects on both physical and mental health. This article describes the features of human trafficking, its physical and mental health effects and the vital role nurses can play in providing care to this vulnerable population.

  4. 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

  5. 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

  6. Nigeria: human trafficking and migration

    Directory of Open Access Journals (Sweden)

    Victoria Ijeoma Nwogu

    2006-05-01

    Full Text Available Readmission agreements between Nigeria and migrant destination countries fail to comply with international standards for the protection of migrants’ and trafficked persons’ rights.

  7. Human Trafficking and National Morality

    Directory of Open Access Journals (Sweden)

    William R. DI PIETRO

    2015-12-01

    Full Text Available The paper proposes that national morality is an important variable for explaining national anti-trafficking policy. It uses cross country regression analysis to see whether or not empirically national morality is a determinant of anti-trafficking policy. The findings of the paper are consistent with the notion that improved levels of national morality lead to better national anti-trafficking policy. National morality is found to be statistically relevant for national anti-trafficking policy when controlling for the extent of democracy, the share of the private sector in the economy, and the degree of globalization.

  8. Autophagy and proteins involved in vesicular trafficking.

    Science.gov (United States)

    Amaya, Celina; Fader, Claudio Marcelo; Colombo, María Isabel

    2015-11-14

    Autophagy is an intracellular degradation system that, as a basic mechanism it delivers cytoplasmic components to the lysosomes in order to maintain adequate energy levels and cellular homeostasis. This complex cellular process is activated by low cellular nutrient levels and other stress situations such as low ATP levels, the accumulation of damaged proteins or organelles, or pathogen invasion. Autophagy as a multistep process involves vesicular transport events leading to tethering and fusion of autophagic vesicles with several intracellular compartments. This review summarizes our current understanding of the autophagic pathway with emphasis in the trafficking machinery (i.e. Rabs GTPases and SNAP receptors (SNAREs)) involved in specific steps of the pathway.

  9. Trafficking in persons: a health concern?

    OpenAIRE

    Cathy Zimmerman; Ligia Kiss; Mazeda Hossain; Charlotte Watts

    2009-01-01

    Human trafficking is a phenomenon that has now been documented in most regions in the world. Although trafficking of women and girls for sexual exploitation is the most commonly recognised form of trafficking, it is widely acknowledged that human trafficking also involves men, women and children who are trafficked for various forms of labour exploitation and into other abusive circumstances. Despite the violence and harm inherent in most trafficking situations, there remains extremely little ...

  10. Lymphatic Regulation of Cellular Trafficking

    Science.gov (United States)

    Jackson, David G.

    2016-01-01

    Lymphatic vessels play vital roles in immune surveillance and immune regulation by conveying antigen loaded dendritic cells, memory T cells, macrophages and neutrophils from the peripheral tissues to draining lymph nodes where they initiate as well as modify immune responses. Until relatively recently however, there was little understanding of how entry and migration through lymphatic vessels is organized or the specific molecular mechanisms that might be involved. Within the last decade, the situation has been transformed by an explosion of knowledge generated largely through the application of microscopic imaging, transgenic animals, specific markers and function blocking mAbs that is beginning to provide a rational conceptual framework. This article provides a critical review of the recent literature, highlighting seminal discoveries that have revealed the fascinating ultrastructure of leucocyte entry sites in lymphatic vessels, as well as generating controversies over the involvement of integrin adhesion, chemotactic and haptotactic mechanisms in DC entry under normal and inflamed conditions. It also discusses the major changes in lymphatic architecture that occur during inflammation and the different modes of leucocyte entry and trafficking within inflamed lymphatic vessels, as well as presenting a timely update on the likely role of hyaluronan and the major lymphatic endothelial hyaluronan receptor LYVE-1 in leucocyte transit.

  11. Behavioural and neuronal activation after microinjections of AMPA and NMDA into the perifornical lateral hypothalamus in rats.

    Science.gov (United States)

    Li, Frederick W; Deurveilher, Samuel; Semba, Kazue

    2011-10-31

    The perifornical lateral hypothalamic area (PeFLH), which houses orexin/hypocretin (OX) neurons, is thought to play an important role in arousal, feeding, and locomotor activity. The present study examined behavioural effects of activating PeFLH neurons with microinjections of ionotropic glutamate receptor agonists. Three separate unilateral microinjections of either (1) AMPA (1 and 2mM in 0.1 μL artificial cerebrospinal fluid, ACSF) and ACSF, or (2) NMDA (1 and 10mM in 0.1 μL ACSF), and ACSF were made into the PeFLH of adult male rats. Following each injection, the rats were placed into an open field for behavioural scoring for 45 min. Rats were perfused after the third injection for immunohistochemistry for c-Fos and OX to assess the level of activation of OX neurons. Behavioural analyses showed that, as compared to ACSF conditions, AMPA injections produced a dose-dependent increase in locomotion and rearing that persisted throughout the 45 min recording period, and an increase in drinking. Injection of NMDA at 10mM, but not 1mM, induced a transient increase in locomotion and an increase in feeding. Histological analyses showed that while both agonists increased the number of neurons immunoreactive for c-Fos in the PeFLH, only AMPA increased the number of neurons immunoreactive for both c-Fos and OX. There were positive correlations between the number of c-Fos/OX-immunoreactive neurons and the amounts of locomotion, rearing, and drinking. These results support the role of ionotropic glutamate receptors on OX and other neurons in the PeFLH in the regulation of locomotor and ingestive behaviours.

  12. Human Trafficking : A Brief Overview

    OpenAIRE

    Makisaka, Megumi

    2009-01-01

    Millions of men, women and children are victims of human trafficking for sexual, forced labor and other forms of exploitation worldwide. The human and economic costs of this take an immense toll on individuals and communities. By conservative estimates, the cost of trafficking in terms of underpayment of wages and recruiting fees is over $20 billion. The costs to human capital are probably...

  13. L-Glutamate and its Ionotropic Receptors in the Nervous System of Cephalopods

    OpenAIRE

    Di Cosmo, A; Di Cristo, C; Messenger, JB

    2006-01-01

    In several species of cephalopod molluscs there is good evidence for the presence of L-glutamate in the central and peripheral nervous system and evidence for both classes of ionotropic receptor, AMPA/kainate and NMDA.

  14. Toxicity of AMPA to the earthworm Eisenia andrei Bouché, 1972 in tropical artificial soil

    OpenAIRE

    Anahí Domínguez; George Gardner Brown; Klaus Dieter Sautter; Cintia Mara Ribas de Oliveira; Eliane Carvalho Vasconcelos; Cintia Carla Niva; Marie Luise Carolina Bartz; José Camilo Bedano

    2016-01-01

    Aminomethylphosphonic acid (AMPA) - one of glyphosate’s main metabolites - has been classified as persistent in soils, raising concern regarding the widespread use of glyphosate in agriculture and forestry. Glyphosate may have negative or neutral effects on soil biota, but no information is available on the toxicity of AMPA to soil invertebrates. Therefore our aim was to study the effect of AMPA on mortality and reproduction of the earthworm species Eisenia andrei using standard soil ecotoxic...

  15. 丙泊酚对大鼠胶质瘤细胞侵袭和迁移能力的影响及ADAR2-AMPA受体GluR2通路在其中的作用%Effects of propofol on invasion and migration of glioma cells in rats and the role of ADAR2-AMPA receptor GluR2 pathway

    Institute of Scientific and Technical Information of China (English)

    王欣悦; 王海云; 王国林; 杨卓; 张涛

    2016-01-01

    目的 评价丙泊酚对大鼠胶质瘤细胞侵袭和迁移能力的影响及腺苷脱氨酶(ADAR2)-α-氨基-3-羟基-5-甲基-4-异恶唑丙酸(AMPA)受体GluR2通路在其中的作用.方法 传代培养大鼠C6胶质瘤细胞,采用随机数字表法分为4组(n=24):对照组(C组)、丙泊酚组(P组)、阴性siRNA转染+丙泊酚组(NP组)和ADAR2-siRNA转染+丙泊酚组(AP组).C组正常培养;NP组和AP组分别将阴性siRNA或ADAR2-siRNA转染至细胞内,48 h后处理同P组;P组加入丙泊酚,终浓度1.2 μg/ml,孵育6h后换为正常培养液,继续培养18h.采用MTT比色分析法检测细胞活力,Transwell侵袭实验测定侵袭细胞数,细胞划痕实验测定迁移率,Western blot法检测胞核ADAR2和胞膜GluR2的表达.结果 与C组比较,P组和NP组细胞活力、侵袭细胞数和迁移率降低,胞核A-DAR2及胞膜GluR2表达上调(P<0.05);与P组比较,AP组细胞活力、侵袭细胞数和迁移率升高,胞核ADAR2及胞膜GluR2表达下调(P<0.05);与NP组比较,AP组细胞活力、侵袭细胞数和迁移率升高,胞核ADAR2及胞膜GluR2表达下调(P<0.05).结论 丙泊酚可抑制大鼠胶质瘤细胞的侵袭和迁移能力,其机制与激活ADAR2-AMPA受体GluR2通路有关.%Objective To evaluate the effects of propofol on the invasion and migration of glioma cells in the rats and the role of adenosine deaminase acting on RNA 2 (ADAR2)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subunit glutamate 2 (GluR2) pathway.Methods C6 glioma cells were subcuhured and randomly divided into 4 groups (n =24 each) using a random number table:control group (group C);propofol group (group P);negative siRNA transfection + propofol group (group NP);ADAR2-siRNA transfection + propofol group (group AP).The cells were cultured in the common culture medium in group C.In NP and AP groups,negative siRNA and ADAR2-siRNA were transfected into the cells,respectively,and 48 h later the other procedures were similar

  16. A new pyrrolyl-quinoxalinedione series of non-NMDA glutamate receptor antagonists: pharmacological characterization and comparison with NBQX and valproate in the kindling model of epilepsy.

    Science.gov (United States)

    Löscher, W; Lehmann, H; Behl, B; Seemann, D; Teschendorf, H J; Hofmann, H P; Lubisch, W; Höger, T; Lemaire, H G; Gross, G

    1999-01-01

    Antagonists at the ionotropic non-NMDA [AMPA (amino-methyl proprionic acid)/kainate] type of glutamate receptors have been suggested to possess several advantages compared to NMDA (N-methyl-D-aspartate) receptor antagonists, particularly in terms of risk/benefit ratio, but the non-NMDA receptor antagonists available so far have not fulfilled this promise. From a large series of pyrrolyl-quinoxalinedione derivatives, we selected six new competitive non-NMDA receptor antagonists. The basis of selection was high potency and selectivity for AMPA and/or kainate receptors, high in vivo potency after systemic administration, and an acceptable ratio between neuroprotective or anticonvulsant effects and adverse effects. Pharmacological characteristics of these novel compounds are described in this study with special emphasis on their effects in the kindling model of temporal lobe epilepsy, the most common type of epilepsy in humans. In most experiments, NBQX and the major antiepileptic drug valproate were used for comparison with the novel compounds. The novel non-NMDA receptor antagonists markedly differed in their AMPA and kainate receptor affinities from NBQX. Thus, while NBQX essentially did not bind to kainate receptors at relevant concentrations, several of the novel compounds exhibited affinity to rat brain kainate receptors or recombinant kainate receptor subtypes in addition to AMPA receptors. One compound, LU 97175, bound to native high affinity kainate receptors and rat GluR5-GluR7 subunits, i.e. low affinity kainate binding sites, with much higher affinities than to AMPA receptors. All compounds potently blocked AMPA-induced cell death in vitro and, except LU 97175, AMPA-induced convulsions in vivo. In the kindling model, compounds with a high affinity for GluR7 (LU 97175) or compounds (LU 115455, LU 136541) which potently bind to AMPA receptors and low affinity kainate receptor subunits were potent anticonvulsants in the kindling model, whereas the AMPA

  17. The threat of illicit trafficking

    International Nuclear Information System (INIS)

    Intelligence services, the army, the navy, the air force and the police together work to avoid illicit trafficking around the world by taking actions as follows: examining the risks and threats of illicit trafficking of radioactive material by terrorists or criminals; gaining a better understanding of current and future patterns and trends in the illicit trafficking of radioactive material; determining progress on efforts to establish detection capabilities at borders and to exchange information on developments in detection technology and response methodologies through installation of radiation detection equipment; strengthening existing networks and cooperation for sharing information on illicit trafficking reports on incidents involving smuggling, theft, loss and illegal disposal, illegal possession and transfer, and attempted illegal sales of the material; examining how an enhanced export/import regime can assist in combating illicit trafficking control through unauthorized movement of radioactive material; sharing information on activities intended to implement international obligations, recommendations and guidance relevant to nuclear security; suggest actions by which the international effort, through the IAEA, would be strengthened. This paper examines the threat and context of illicit nuclear trafficking of radioactive material, what is being done to combat such trafficking and highlights where more needs to be done

  18. 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...

  19. INTERNATIONAL COOPERATION AGAINST HUMAN TRAFFICKING

    OpenAIRE

    Ionita COCHINTU; Laura TUTUNARU; Narcisa Mihaela STOICU; Daniela Cristina VALEA

    2011-01-01

    Trafficking in human beings, a phenomenon with global dimensions constitutes a serious violation of human rights, dignity and freedom, a social phenomenon with negative consequences for the entire society. Countries have been concerned over the time to find the most effective policy measures to combat and prevent human trafficking, and in this regard the United Nations, the European Union and the Council of Europe have developed a series of international documents which established an interna...

  20. Illicit Trafficking of Natural Radionuclides

    Science.gov (United States)

    Friedrich, Steinhäusler; Lyudmila, Zaitseva

    2008-08-01

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  1. Integrin Trafficking and Tumor Progression

    Directory of Open Access Journals (Sweden)

    Sejeong Shin

    2012-01-01

    Full Text Available Integrins are major mediators of cancer cell adhesion to extracellular matrix. Through this interaction, integrins play critical roles in cell migration, invasion, metastasis, and resistance to apoptosis during tumor progression. Recent studies highlight the importance of integrin trafficking, endocytosis and recycling, for the functions of integrins in cancer cells. Understanding the molecular mechanisms of integrin trafficking is pivotal for understanding tumor progression and for the development of anticancer drugs.

  2. Illicit Trafficking of Natural Radionuclides

    International Nuclear Information System (INIS)

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces

  3. 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...... and AMPA (and NMDA) in hippocampal slice cultures, and --b) KA and AMPA in corticostriatal slice cocultures, with demonstration of differentiated neuroprotective effects of NBQX in relation to cortex and striatum and KA and AMPA. A second set of studies include modulation of hippocampal KA......-induced excitotoxicity and KA-glutamate receptor subunit mRNA expression after long-term exposure to low, non-toxic doses of KA and NBQX. We conclude that organotypic brain slice cultures, combined with standardized procedures for quantitation of cell damage and receptor subunit changes is of great potential use...

  4. Sex trafficking in South Asia.

    Science.gov (United States)

    Huda, S

    2006-09-01

    Economic and social inequalities and political conflicts have led to the movement of persons within each country and across the borders in South Asia. Globalization has encouraged free mobility of capital, technology, experts and sex tourism. Illiteracy, dependency, violence, social stigma, cultural stereotypes, gender disparity and endemic poverty, among other factors, place women and children in powerless, non-negotiable situations that have contributed to the emergence and breeding of the cavernous problem of sex trafficking in the entire region. This alarming spread of sex trafficking has fuelled the spread of HIV infection in South Asia, posing a unique and serious threat to community health, poverty alleviation and other crucial aspects of human development. Although the SAARC (South Asian Association for Regional Cooperation) Convention on Trafficking in Women and Children has been an important breakthrough, most of the countries in the region do not have anti-trafficking legislation or means to protect the victims. Countries of the region should make a concerted effort to treat trafficking victims as "victims" of human rights violations in all anti-trafficking strategies and actions.

  5. Pengaruh Ampas Tebu sebagai Adsorbent pada Proses Pretreatment Minyak Jelantah terhadap Karakteristik Biodiesel

    Directory of Open Access Journals (Sweden)

    Ratno Ratno

    2013-09-01

    Full Text Available Telah dilakukan penelitian mengenai pengaruh ampas tebu pada proses pretreatment minyak jelantah terhadap karakteristik biodiesel. Proses pretreatment dilakukan sebelum minyak jelantah diolah menjadi biodiesel, yakni ampas tebu dengan ukuran partikel dan massa yang bervariasi direndam pada minyak tersebut selama 2 jam. Ukuran partikel ampas tebu yang digunakan adalah 80, 115, 170, dan 200 mesh, sedangkan massa ampas tebu divariasi untuk tiap ukuran partikel yaitu 25 gram, 37,5 gram, dan 50 gram. Penggunaan ampas tebu sebagai adsorbent dinilai cukup efektif menurunkan kadar asam lemak bebas (FFA minyak jelantah dengan penurunan terbesar 57,3% terjadi pada minyak jelantah yang telah mengalami pretreatment ampas tebu berukuran partikel 200 mesh sebanyak 50 gram. Biodiesel dibuat dengan mereaksikan minyak jelantah yang telah mengalami pretreatment ampas tebu dengan lauratan Methanol dan Kalium Hidroksida (KOH selama 1 jam pada suhu 55oC. Hasil karakterisasi  menunjukkan bahwa massa jenis, titik nyala, titik kabut, dan titik tuang biodiesel telah memenuhi standar SNI-04-7182-2006 kecuali sampel yang mengalami pretreatment dengan ampas tebu 80 mesh sebanyak 25 gram. Sedangkan viskositas kinematik terdapat 5 sampel yang memenuhi untuk standar yang sama.

  6. To discuss illicit nuclear trafficking

    Energy Technology Data Exchange (ETDEWEB)

    Balatsky, Galya I [Los Alamos National Laboratory; Severe, William R [Los Alamos National Laboratory; Wallace, Richard K [Los Alamos National Laboratory

    2010-01-01

    The Illicit nuclear trafficking panel was conducted at the 4th Annual INMM workshop on Reducing the Risk from Radioactive and Nuclear Materials on February 2-3, 2010 in Washington DC. While the workshop occurred prior to the Nuclear Security Summit, April 12-13 2010 in Washington DC, some of the summit issues were raised during the workshop. The Communique of the Washington Nuclear Security Summit stated that 'Nuclear terrorism is one of the most challenging threats to international security, and strong nuclear security measures are the most effective means to prevent terrorists, criminals, or other unauthorized actors from acquiring nuclear materials.' The Illicit Trafficking panel is one means to strengthen nuclear security and cooperation at bilateral, regional and multilateral levels. Such a panel promotes nuclear security culture through technology development, human resources development, education and training. It is a tool which stresses the importance of international cooperation and coordination of assistance to improve efforts to prevent and respond to incidents of illicit nuclear trafficking. Illicit trafficking panel included representatives from US government, an international organization (IAEA), private industry and a non-governmental organization to discuss illicit nuclear trafficking issues. The focus of discussions was on best practices and challenges for addressing illicit nuclear trafficking. Terrorism connection. Workshop discussions pointed out the identification of terrorist connections with several trafficking incidents. Several trafficking cases involved real buyers (as opposed to undercover law enforcement agents) and there have been reports identifying individuals associated with terrorist organizations as prospective plutonium buyers. Some specific groups have been identified that consistently search for materials to buy on the black market, but no criminal groups were identified that specialize in nuclear materials or isotope

  7. Water quality of the main tributaries of the Paraná Basin: glyphosate and AMPA in surface water and bottom sediments.

    Science.gov (United States)

    Ronco, A E; Marino, D J G; Abelando, M; Almada, P; Apartin, C D

    2016-08-01

    The Paraná River, the sixth largest in the world, is the receptor of pollution loads from tributaries traversing urban and industrialized areas plus agricultural expanses, particularly so in the river's middle and lower reaches along the Argentine sector. In the present study, we analyzed and discussed the main water quality parameters, sediment compositions, and content of the herbicide glyphosate plus its metabolite aminomethylphosphonic acid (AMPA) in water and sediments. Samples were obtained from distal positions in the principal tributaries of the Paraná and the main watercourse during surveys conducted in 2011 and 2012 to monitor the basin. Only 15 % of the water samples contained detectable concentrations of glyphosate at an average concentration of 0.60 μg/L, while no detectable levels of AMPA were observed. The herbicide and metabolite were primarily present in sediments of the middle and lower stretch's tributaries, there occurring at a respective average of 37 and 17 % in samples. The mean detectable concentrations measured were 742 and 521 μg/kg at mean, maximum, and minimum glyphosate/AMPA ratios of 2.76, 7.80, and 0.06, respectively. The detection of both compounds was correlated with the presence of sulfides and copper in the sediment matrix. PMID:27395359

  8. Effect of brain-derived neurotrophic factor on activity-regulated cytoskeleton-associated protein gene expression in primary frontal cortical neurons. Comparison with NMDA and AMPA

    DEFF Research Database (Denmark)

    El-Sayed, Mona; Hofman-Bang, Jacob; Mikkelsen, Jens D

    2011-01-01

    The effect of brain-derived neurotrophic factor (BDNF) on activity-regulated cytoskeleton-associated protein (Arc) mRNA levels in primary neuronal cultures of rat frontal cortex was characterized pharmacologically and compared to the effect on expression of c-fos, bdnf, neuritin, cox-2 as examples...... of other immediate early genes. BDNF induced a very strong increase (around 100 fold) in Arc mRNA and the maximal effect seen at 25 ng/ml. The effect was dose-dependent with EC50 around 1.6 ng/ml. The time profile revealed a significant effect after 25 min. BDNF also increased levels of c-Fos, neuritin...... and BDNF mRNA, but not COX-2 mRNA. The pharmacological profile of NMDA and AMPA-induced arc gene expression in frontal cortical neurons was compared to BDNF. NMDA and AMPA increased Arc mRNA but their maximal effect did not exceed 20-fold. The effect of AMPA was completely blocked by the NMDA receptor...

  9. A preliminary experimental study on the cardiac toxicity of glutamate and the role of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor in rats

    Institute of Scientific and Technical Information of China (English)

    LIU Yan; ZHOU Lan; XU Hai-fei; YAN Li; DING Fan; HAO Wei; CAO Ji-min

    2013-01-01

    Background Monosodium L-glutamate (MSG) is a food flavour enhancer and its potential harmfulness to the heart remains controversial.We investigated whether MSG could induce cardiac arrhythmias and apoptosis via the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor.Methods Myocardial infarction (MI) was created by ligating the coronary artery and ventricular arrhythmias were monitored by electrocardiogram in the rat in vivo.Neonatal rat cardiomyocytes were isolated and cultured.Cell viability was estimated by 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-di-phenytetrazoliumromide (MTT) assay.Calcium mobilization was monitored by confocal microscopy.Cardiomyocyte apoptosis was evaluated by acridine orange staining,flow cytometry,DNA laddering,reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Results MSG (i.v.) decreased the heart rate at 0.5 g/kg and serious bradycardia at 1.5 g/kg,but could not induce ventricular tachyarrhythmias in normal rats in vivo.In rats with acute MI in vivo,however,MSG (1.5 g/kg,i.v.) induced ventricular tachyarrhythmias and these arrhythmias could be prevented by blocking the AMPA and N-methyl-d-aspartate (NMDA) receptors.Selectively activating the AMPA or NMDA receptor induced ventricular tachyarrhythmias in MI rats.At the cellular level,AMPA induced calcium mobilization,oxidative stress,mitochondrial dysfunction and apoptosis in cultured cardiomyocytes,especially when the AMPA receptor desensitization were blocked by cyclothiazide.The above toxic cellular effects of AMPA were abolished by AMPA receptor blockade or by H2O2 scavengers.Conclusions MSG induces bradycardia in normal rats,but triggers lethal tachyarrhythmias in myocardial infarcted rats probably by hindering AMPA receptors.AMPA receptor overstimulation also induces cardiomyocyte apoptosis,which may facilitate arrhythmia.

  10. Trafficking: a perspective from Asia.

    Science.gov (United States)

    Skeldon, R

    2000-01-01

    The main theme of this article is market development and trafficking as a business. It touches upon most of the aspects of the phenomenon, which have been encountered elsewhere, and translates them into the relatively unfamiliar context of many of the Asian and South-East Asian economies. Equally, the literature cited is also probably unfamiliar. Themes touched upon include democratization, inter-state relations, human rights, and scale and perspectives, together with the problems of definitions, theory, and the reliability of data. The directions and characteristics of trafficking flows together with routes and border control are also considered. Coordinated official responses to criminality and criminal organizations, as well as to trafficked individuals, are beginning to emerge. There is a note of caution sounded that contextual and cultural perspectives, particularly on sex workers, must be viewed somewhat differently to those in Western societies. The article concludes that as long as countries in Asia maintain their policies of restrictive immigration, trafficking can be expected to continue and almost certainly increase. This is because accelerating development creates demand for labor at various skill levels and because even in times of recession migrants and brokers will seek to side-step attempts to expel immigrants and restrict access to labor markets. The elimination of trafficking is unlikely to be realistically achieved through legislation and declarations of intent but by improvements in the socioeconomic status of the population.

  11. Pharmacological characterisation of murine α4β1δ GABAA receptors expressed in Xenopus oocytes

    DEFF Research Database (Denmark)

    Villumsen, Inge S; Wellendorph, Petrine; Smart, Trevor G

    2015-01-01

    BACKGROUND: GABAA receptor subunit composition has a profound effect on the receptor's physiological and pharmacological properties. The receptor β subunit is widely recognised for its importance in receptor assembly, trafficking and post-translational modifications, but its influence on...

  12. Trafficking in persons: a health concern?

    Science.gov (United States)

    Zimmerman, Cathy; Kiss, Ligia; Houssain, Mazeda; Watts, Charlotte

    2009-01-01

    Human trafficking is a phenomenon that has now been documented in most regions in the world. Although trafficking of women and girls for sexual exploitation is the most commonly recognised form of trafficking, it is widely acknowledged that human trafficking also involves men, women and children who are trafficked for various forms of labour exploitation and into other abusive circumstances. Despite the violence and harm inherent in most trafficking situations, there remains extremely little evidence on the individual and public health implications of any form of human trafficking. The Brazilian government has recently launched a national plan to combat human trafficking. However, because the health risks associated with human trafficking have not been well-recognised or documented, there is extremely limited reliable data on the health needs of trafficked persons to inform policy and practices.. Brazilian policy-makers and service providers should be encouraged to learn about the likely range of health impacts of trafficking, and incorporate this into anti-trafficking protection and response strategies. As well as prevention activities, the government, international and local organisations should work together with the public health research community to study the health needs of trafficked persons and explore opportunities to provide safe and appropriate services to victims in need of care. PMID:19721944

  13. Trafficking in persons: a health concern?

    Directory of Open Access Journals (Sweden)

    Cathy Zimmerman

    2009-08-01

    Full Text Available Human trafficking is a phenomenon that has now been documented in most regions in the world. Although trafficking of women and girls for sexual exploitation is the most commonly recognised form of trafficking, it is widely acknowledged that human trafficking also involves men, women and children who are trafficked for various forms of labour exploitation and into other abusive circumstances. Despite the violence and harm inherent in most trafficking situations, there remains extremely little evidence on the individual and public health implications of any form of human trafficking. The Brazilian government has recently launched a national plan to combat human trafficking. However, because the health risks associated with human trafficking have not been well-recognised or documented, there is extremely limited reliable data on the health needs of trafficked persons to inform policy and practices.. Brazilian policy-makers and service providers should be encouraged to learn about the likely range of health impacts of trafficking, and incorporate this into anti-trafficking protection and response strategies. As well as prevention activities, the government, international and local organisations should work together with the public health research community to study the health needs of trafficked persons and explore opportunities to provide safe and appropriate services to victims in need of care.

  14. Molecular nuclear imaging for targeting and trafficking

    International Nuclear Information System (INIS)

    Noninvasive molecular targeting in living subjects is highly demanded for better understanding of such diverse topics as the efficient delivery of drugs, genes, or radionuclides for the diagnosis or treatment of diseases. Progress in molecular biology, genetic engineering and polymer chemistry provides various tools to target molecules and cells in vivo. We used chitosan as a polymer, and 99mTc as a radionuclide. We developed 99mTc-galactosylated chitosan to target asialoglycoprotein receptors for nuclear imaging. We also developed 99mTc-HYNIC-chitosan-transferrin to target inflammatory cells, which was more effective than 67Ga-citrate for imaging inflammatory lesions. For an effective delivery of molecules, a longer circulation time is needed. We found that around 10% PEGylation was most effective to prolong the circulation time of liposomes for nuclear imaging of 99mTc-HMPAO-labeled liposomes in rats. Using various characteristics of molecules, we can deliver drugs into targets more effectively. We found that 99mTc-labeled biodegradable pullulan-derivatives are retained in tumor tissue in response to extracellular ion-strength. For the trafficking of various cells or bacteria in an intact animal, we used optical imaging techniques or radiolabeled cells. We monitored tumor-targeting bacteria by bioluminescent imaging techniques, dentritic cells by radiolabeling and neuronal stem cells by sodium-iodide symporter reporter gene imaging. In summary, we introduced recent achievements of molecular nuclear imaging technologies in targeting receptors for hepatocyte or inflammatory cells and in trafficking bacterial, immune and stem cells using molecular nuclear imaging techniques

  15. 78 FR 40619 - Combating Wildlife Trafficking

    Science.gov (United States)

    2013-07-05

    ... ``wildlife trafficking'') represent an international crisis that continues to escalate. Poaching operations..., rhinos, great apes, tigers, sharks, tuna, and turtles has beneficial economic, social, and environmental... develop and implement a National Strategy for Combating Wildlife Trafficking in accordance with...

  16. Understanding human trafficking in the United States.

    Science.gov (United States)

    Logan, T K; Walker, Robert; Hunt, Gretchen

    2009-01-01

    The topic of modern-day slavery or human trafficking has received increased media and national attention. However, to date there has been limited research on the nature and scope of human trafficking in the United States. This article describes and synthesizes nine reports that assess the U.S. service organizations' legal representative knowledge of, and experience with, human trafficking cases, as well as information from actual cases and media reports. This article has five main goals: (a) to define what human trafficking is, and is not; (b) to describe factors identified as contributing to vulnerability to being trafficked and keeping a person entrapped in the situation; (c) to examine how the crime of human trafficking differs from other kinds of crimes in the United States; (d) to explore how human trafficking victims are identified; and, (e) to provide recommendations to better address human trafficking in the United States.

  17. Does legalized prostitution increase human trafficking?

    OpenAIRE

    Cho, Seo-Young; Dreher, Axel; Neumayer, Eric

    2013-01-01

    This paper investigates the impact of legalized prostitution on human trafficking inflows. According to economic theory, there are two opposing effects of unknown magnitude. The scale effect of legalized prostitution leads to an expansion of the prostitution market, increasing human trafficking, while the substitution effect reduces demand for trafficked women as legal prostitutes are favored over trafficked ones. Our empirical analysis for a cross-section of up to 150 countries shows that th...

  18. Barriers to combating human trafficking in Colombia

    OpenAIRE

    Wilcox, Daniel Joseph

    2015-01-01

    Approved for public release; distribution is unlimited Despite international and domestic policies and programs intended to combat human trafficking, Colombia remains one of the countries with the highest instances of human trafficking in the Western Hemisphere. Factors contributing to human trafficking in Colombia, such as internal violence and displacement, drug trafficking, a weak central government, and widespread corruption, have overpowered what energies the government marshaled agai...

  19. TRAFFICKING OF CHILDREN IN ROMANI COMMUNITIES

    OpenAIRE

    Daniela Vacaretu

    2011-01-01

    The paper intends to emphasize the graveness of human trafficking in Romani communities since in most of the cases it involves children. Human trafficking as a global issue is welcome but there is a danger of sensationalizing the issue, particularly when it comes to Roma. One must not make the mistake and consider any act of migration of Roma as trafficking, though, must not explain and consider trafficking as an act of voluntary migrations. Indeed, this makes it even more difficult for natio...

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

    DEFF Research Database (Denmark)

    de Turco, Elena B; Diemer, Nils Henrik; Bazan, Nicolas G;

    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]A...

  1. L-(TH)glutamate binds to kainate-, NMDA- and AMPA-sensitive binding sites: an autoradiographic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Monaghan, D.T.; Yao, D.; Cotman, C.W.

    1985-08-12

    The anatomical distribution of L-(TH)glutamate binding sites was determined in the presence of various glutamate analogues using quantitative autoradiography. The binding of L-(TH)glutamate is accounted for by the presence of 3 distinct binding sites when measured in the absence of CaS , Cl and Na ions. The anatomical distribution and pharmacological specificity of these binding sites correspond to that reported for the 3 excitatory amino acid binding sites selectively labelled by D-(TH)2-amino-5-phosphonopentanoate (D-(TH)AP5), (TH)kainate ((TH)KA) and (TH) -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ((TH)AMPA) which are thought to be selective ligands for the N-methyl-D-aspartate (NMDA), KA and quisqualate (QA) receptors, respectively. (Auth.). 29 refs.; 1 figure; 1 table.

  2. Cellular membrane trafficking of mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Fang, I-Ju [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine

  3. Human trafficking in domestic legislature

    Directory of Open Access Journals (Sweden)

    Skakavac Zdravko

    2008-01-01

    Full Text Available Human trafficking is an occurrence that, even in our time, is present in alarming proportions, in its actuality and consequences. It is a phenomenon with a long history and has been qualified as a serious international problem and is the object of interest for a large number of international subjects. However, the key international document that defines this phenomenon is the Convention against Transnational Organized Crime from Palermo 2000; specifically its Protocol to Prevent, Suppress and Punish Trafficking in Persons, especially Women and Children. After its adoption, intensive actions were undertaken to regulate the phenomenon on the level of national legislature. It's done so in the local legislature too. According to the criminal law of the republic of Serbia, besides the concrete law against human trafficking, a number of other crimes are connected to human trafficking. This paper deals with the most important ones. The purpose of this paper is to review the legislature on the phenomenon in the domestic law, then the accordance of incrimination with international standards, as well as to indicate the need for further changes in domestic legislature.

  4. Leukocyte Trafficking to the Small Intestine and Colon.

    Science.gov (United States)

    Habtezion, Aida; Nguyen, Linh P; Hadeiba, Husein; Butcher, Eugene C

    2016-02-01

    Leukocyte trafficking to the small and large intestines is tightly controlled to maintain intestinal immune homeostasis, mediate immune responses, and regulate inflammation. A wide array of chemoattractants, chemoattractant receptors, and adhesion molecules expressed by leukocytes, mucosal endothelium, epithelium, and stromal cells controls leukocyte recruitment and microenvironmental localization in intestine and in the gut-associated lymphoid tissues (GALTs). Naive lymphocytes traffic to the gut-draining mesenteric lymph nodes where they undergo antigen-induced activation and priming; these processes determine their memory/effector phenotypes and imprint them with the capacity to migrate via the lymph and blood to the intestines. Mechanisms of T-cell recruitment to GALT and of T cells and plasmablasts to the small intestine are well described. Recent advances include the discovery of an unexpected role for lectin CD22 as a B-cell homing receptor GALT, and identification of the orphan G-protein-coupled receptor 15 (GPR15) as a T-cell chemoattractant/trafficking receptor for the colon. GPR15 decorates distinct subsets of T cells in mice and humans, a difference in species that could affect translation of the results of mouse colitis models to humans. Clinical studies with antibodies to integrin α4β7 and its vascular ligand mucosal vascular addressin cell adhesion molecule 1 are proving the value of lymphocyte trafficking mechanisms as therapeutic targets for inflammatory bowel diseases. In contrast to lymphocytes, cells of the innate immune system express adhesion and chemoattractant receptors that allow them to migrate directly to effector tissue sites during inflammation. We review the mechanisms for innate and adaptive leukocyte localization to the intestinal tract and GALT, and discuss their relevance to human intestinal homeostasis and inflammation.

  5. 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...

  6. Glyphosate and AMPA in the estuaries of the Baltic Sea method optimization and field study.

    Science.gov (United States)

    Skeff, Wael; Neumann, Christine; Schulz-Bull, Detlef E

    2015-11-15

    Water samples from ten German Baltic estuaries were collected in 2012 in order to study the presence of the herbicide glyphosate, its primary metabolite AMPA and their potential transport to the marine environment. For the analyses an LC-MS/MS based analytical method after derivatization with FMOC-Cl was optimized and validated for marine water samples. All investigated estuarine stations were contaminated with AMPA and nine of them also with glyphosate. Concentration ranges observed were 28 to 1690ng/L and 45 to 4156ng/L for glyphosate and AMPA, respectively with strong spatial and temporal fluctuations. Both contaminants were found at inbound sampling sites in the stream Muehlenfliess and concentrations decreased along the salinity gradient to the estuaries of the Baltic Sea. The data obtained in this study clearly depict the transport of glyphosate and AMPA to the Baltic Sea. Hence, detailed fate and risk assessment for both contaminants in marine environments are required.

  7. Human trafficking and the healthcare professional.

    Science.gov (United States)

    Barrows, Jeffrey; Finger, Reginald

    2008-05-01

    Despite the legislation passed in the 19th century outlawing human slavery, it is more widespread today than at the conclusion of the civil war. Modern human slavery, termed human trafficking, comes in several forms. The most common type of human trafficking is sex trafficking, the sale of women and children into prostitution. Labor trafficking is the sale of men, women, and children into hard labor for which they receive little or no compensation. Other forms of trafficking include child soldiering, war brides, and organ removal. Healthcare professionals play a critical role in both finding victims of human trafficking while they are still in captivity, as well as caring for their mental and physical needs upon release. Those working in the healthcare profession need to be educated regarding how a trafficking victim may present, as well as their unique healthcare needs.

  8. Basic fibroblast growth factor increases the number of endogenous neural stem cells and inhibits the expression of amino methyl isoxazole propionic acid receptors in amyotrophic lateral sclerosis mice

    Institute of Scientific and Technical Information of China (English)

    Weihui Huang; Dawei Zang; Yi Lu; Ping Jiang

    2012-01-01

    This study aimed to investigate the number of amino methyl isoxazole propionic acid (AMPA) re-ceptors and production of endogenous neural stem cells in the SOD1G93AG1H transgenic mouse model of amyotrophic lateral sclerosis, at postnatal day 60 following administration of basic fibroblast growth factor (FGF-2). A radioligand binding assay and immunohistochemistry were used to estimate the number of AMPA receptors and endogenous neural stem cells respectively. Results showed that the number of AMPA receptors and endogenous neural stem cells in the brain stem and sensorimotor cortex were significantly increased, while motor function was significantly decreased at postnatal days 90 and 120. After administration of FGF-2 into mice, numbers of endogenous neural stem cells increased, while expression of AMPA receptors decreased, whilst motor functions were recovered. At postnatal day 120, the number of AMPA receptors was negatively correlated with the number of endogenous neural stem cells in model mice and FGF-2-treated mice. Our experimental findings indicate that FGF-2 can inhibit AMPA receptors and increase the number of endogenous neural stem cells, thus repairing neural injury in amyotrophic lateral sclerosis mice.

  9. EXPRESSION OF AMPA RECEPTORS AND RELATED PROTEIN IN IMMOBILIZATION STRESSED RATS AND EFFECT OF XIAOYAOSAN%AMPA受体和相关蛋白在束缚应激大鼠相关脑区的表达变化及逍遥散对其影响

    Institute of Scientific and Technical Information of China (English)

    岳广欣; 王竹风; 张巧丽; 赵歆; 岳利峰; 丁杰; 陈家旭

    2008-01-01

    目的:观察海马及杏仁核α-氨基羟甲基恶唑丙酸(AMPA)受体亚基和相关调节蛋白在束缚应激状态下蛋白表达变化及逍遥散的调节作用.方法:使用每天捆绑3 h的方法制作慢性束缚应激动物模型,并用逍遥散进行干预,分别于7 d后和21 d后用western blot方法检测各组大鼠海马CA1区、CA3区、齿状回(DG)和杏仁核的AMPA受体亚基GluR2/3及N-乙基顺丁烯二酰亚胺敏感性的融合蛋白(NSF)、PKC作用蛋白1(PICK1)蛋白表达的情况.结果:7 d应激可使DG和杏仁核的GluR2/3、NSF表达显著降低(P均<0.1315),使PICK1在CA1区的表达量显著增多(P<0.05),逍遥散对PICK1变化显示出一定调节作用.21 d应激可使CA1区的GluR2/3、NSF表达升高,其中GluR2/3有显著性差异(P<0.01),而在杏仁核表达有降低趋势,逍遥散对其均有显著调节作用(均为P<0.05),21 d应激使杏仁核PICK1表达量出现升高趋势,逍遥散可显著降低其表达(P<0.05).结论:AMPA受体在短期重复应激和慢性应激状态下反应不同,海马和杏仁核反应相反,逍遥散对慢性应激状态下AMPA受体表达的调节作用较短期重复应激强.

  10. 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. PMID:27155486

  11. 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.

  12. Toxicity of AMPA to the earthworm Eisenia andrei Bouché, 1972 in tropical artificial soil.

    Science.gov (United States)

    Domínguez, Anahí; Brown, George Gardner; Sautter, Klaus Dieter; de Oliveira, Cintia Mara Ribas; de Vasconcelos, Eliane Carvalho; Niva, Cintia Carla; Bartz, Marie Luise Carolina; Bedano, José Camilo

    2016-01-01

    Aminomethylphosphonic acid (AMPA) - one of glyphosate's main metabolites - has been classified as persistent in soils, raising concern regarding the widespread use of glyphosate in agriculture and forestry. Glyphosate may have negative or neutral effects on soil biota, but no information is available on the toxicity of AMPA to soil invertebrates. Therefore our aim was to study the effect of AMPA on mortality and reproduction of the earthworm species Eisenia andrei using standard soil ecotoxicological methods (ISO). Field-relevant concentrations of AMPA had no significant effects on mortality in acute or chronic assays. Except at the highest concentration tested, a significant biomass loss was observed compared to controls in the chronic assay. The number of juveniles and cocoons increased with higher concentrations of AMPA applied, but their mean weights decreased. This mass loss indicates higher sensitivity of juveniles than adults to AMPA. Our results suggest that earthworms coming from parents grown in contaminated soils may have reduced growth, limiting their beneficial roles in key soil ecosystem functions. Nevertheless, further research is needed to better understand the mechanisms underlying the sublethal effects observed here. PMID:26792548

  13. Ceftriaxone attenuates cocaine relapse after abstinence through modulation of nucleus accumbens AMPA subunit expression.

    Science.gov (United States)

    LaCrosse, Amber L; Hill, Kristine; Knackstedt, Lori A

    2016-02-01

    Using the extinction-reinstatement model of cocaine relapse, we and others have demonstrated that the antibiotic ceftriaxone attenuates cue- and cocaine-primed reinstatement of cocaine-seeking. Reinstatement is contingent on the release of glutamate in the nucleus accumbens core (NAc) and manipulations that reduce glutamate efflux or block post-synaptic glutamate receptors attenuate reinstatement. We have demonstrated that the mechanism of action by which ceftriaxone attenuates reinstatement involves increased NAc GLT-1 expression and a reduction in NAc glutamate efflux during reinstatement. Here we investigated the effects of ceftriaxone (100 and 200 mg/kg) on context-primed relapse following abstinence without extinction training and examined the effects of ceftriaxone on GluA1, GluA2 and GLT-1 expression. We conducted microdialysis during relapse to determine if an increase in NAc glutamate accompanies relapse after abstinence and whether ceftriaxone blunts glutamate efflux. We found that both doses of ceftriaxone attenuated relapse. While relapse was accompanied by an increase in NAc glutamate, ceftriaxone (200 mg/kg) was unable to significantly reduce NAc glutamate efflux during relapse despite its ability to upregulate GLT-1. GluA1 was reduced in the NAc by both doses of ceftriaxone while GluA2 expression was unchanged, indicating that ceftriaxone altered AMPA subunit composition following cocaine. Finally, GLT-1 was not altered in the PFC by ceftriaxone. These results indicate that it is possible to attenuate context-primed relapse to cocaine-seeking through modification of post-synaptic receptor properties without attenuating glutamate efflux during relapse. Furthermore, increasing NAc GLT-1 protein expression is not sufficient to attenuate glutamate efflux.

  14. Ceftriaxone attenuates cocaine relapse after abstinence through modulation of nucleus accumbens AMPA subunit expression.

    Science.gov (United States)

    LaCrosse, Amber L; Hill, Kristine; Knackstedt, Lori A

    2016-02-01

    Using the extinction-reinstatement model of cocaine relapse, we and others have demonstrated that the antibiotic ceftriaxone attenuates cue- and cocaine-primed reinstatement of cocaine-seeking. Reinstatement is contingent on the release of glutamate in the nucleus accumbens core (NAc) and manipulations that reduce glutamate efflux or block post-synaptic glutamate receptors attenuate reinstatement. We have demonstrated that the mechanism of action by which ceftriaxone attenuates reinstatement involves increased NAc GLT-1 expression and a reduction in NAc glutamate efflux during reinstatement. Here we investigated the effects of ceftriaxone (100 and 200 mg/kg) on context-primed relapse following abstinence without extinction training and examined the effects of ceftriaxone on GluA1, GluA2 and GLT-1 expression. We conducted microdialysis during relapse to determine if an increase in NAc glutamate accompanies relapse after abstinence and whether ceftriaxone blunts glutamate efflux. We found that both doses of ceftriaxone attenuated relapse. While relapse was accompanied by an increase in NAc glutamate, ceftriaxone (200 mg/kg) was unable to significantly reduce NAc glutamate efflux during relapse despite its ability to upregulate GLT-1. GluA1 was reduced in the NAc by both doses of ceftriaxone while GluA2 expression was unchanged, indicating that ceftriaxone altered AMPA subunit composition following cocaine. Finally, GLT-1 was not altered in the PFC by ceftriaxone. These results indicate that it is possible to attenuate context-primed relapse to cocaine-seeking through modification of post-synaptic receptor properties without attenuating glutamate efflux during relapse. Furthermore, increasing NAc GLT-1 protein expression is not sufficient to attenuate glutamate efflux. PMID:26706696

  15. HUMAN TRAFFICKING. TRAFFICKING IN CHILDREN. PRACTICAL ASPECTS REGARDING CHILDREN EXPLOITATION

    OpenAIRE

    Raluca-Ioana Rosu

    2010-01-01

    900 thousand children are working in their own households and 70 thousand were victims of worst forms of child labor, including sexual exploitation, forced work, trafficking in children, involvement in criminal activities and risk exposure. Also, approximately 3 thousand street children were involved in: products selling in the street, beggary or windshields washing. In Roma communities, the work of young children (even of 5 years old) is still a frequent practice. Isolated cases of girls inv...

  16. 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. PMID:27092715

  17. 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.

  18. Regulation of the Ionotropic Glutamate Receptor Trafficking by Protein Palmitoylation%蛋白质棕榈酰化对离子型谷氨酸受体运输的调节作用

    Institute of Scientific and Technical Information of China (English)

    冯晨; 冯磊

    2010-01-01

    棕榈酰化是一种可逆的翻译后修饰,其对蛋白质的定位和功能具有重要的调节意义.离子型谷氨酸受体有N-甲基-D-天冬氨酸(NMDA)受体、α-氨基羟甲基恶唑丙酸(AMPA)受体和人海藻酸受体.近期研究发现,它们的棕榈酰化修饰对其膜表面分布和内化均具有重要的意义.其中NMDA受体在其C末端有2个不同的棕榈酰化位点.1个位于C末端近膜区(Cys cluster Ⅰ),它的棕榈酰化可以增高酪氨酸的磷酸化水平,增加受体膜表面分布,影响神经元中NMDA受体的组构性内化;另1个位于C末端中部(Cys clusterⅡ),它受到蛋白质酰基转移酶GODZ的调节,使得受体在高尔基体大量积聚,从而影响受体的膜表面分布.与NMDA受体相似,AMPA受体也存在2个棕榈酰化位点.1个位于在第2跨膜域,受蛋白质酰基转移酶GODZ的调节,能导致AMPA受体在高尔基体的积聚.另1个位点在受体C末端近膜区,它的棕榈酰化能降低AMPA受体和4.1 N蛋白的相互作用,并调节受体的内化.这两种离子型谷氨酸受体在棕榈酰化机制上虽然存在差异,但均对受体的运输、膜表面分布和内化具有十分重要的作用.

  19. 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

  20. Human organ trafficking in the cyber space

    OpenAIRE

    Vuletić Dejan

    2009-01-01

    The accelerated growth of the information-communication technology use brought about cyber crime as a new form of crime connected with the misuse of computer network. Human trafficking and human organ trafficking are changing in line with the state-of-art technological achievements i.e. becoming more and more characteristic of cyber space. Passing appropriate regulations at both national and international levels presents an important step in solving the problem of human organ trafficking thro...

  1. Psychological characteristics of victims of trafficking

    OpenAIRE

    Larin A.N.

    2015-01-01

    The article describes the main causes of falling into slavery, forms of slave labour, as well as moral-psychological properties and characteristics of potential victims of trafficking. Noted risk factors leading to victimization of the person and increase the possibility of becoming an object for criminal groups specializing in this kind of crime. The number of victims of international trafficking ranges from 600 to 800 thousand people a year, and when you consider human trafficking within th...

  2. Human organ trafficking in the cyber space

    Directory of Open Access Journals (Sweden)

    Vuletić Dejan

    2009-01-01

    Full Text Available The accelerated growth of the information-communication technology use brought about cyber crime as a new form of crime connected with the misuse of computer network. Human trafficking and human organ trafficking are changing in line with the state-of-art technological achievements i.e. becoming more and more characteristic of cyber space. Passing appropriate regulations at both national and international levels presents an important step in solving the problem of human organ trafficking through Internet.

  3. Human Trafficking in the Emergency Department

    OpenAIRE

    Ahn, Roy; Burke, Thomas; Patel, Ronak B.

    2010-01-01

    Human trafficking continues to persist, affecting up to 200 million people worldwide. As clinicians in emergency departments commonly encounter victims of intimate partner violence, some of these encounters will be with trafficking victims. These encounters provide a rare opportunity for healthcare providers to intervene and help. This case report of a human trafficking patient from a teaching hospital illustrates the complexity in identifying these victims. Clinicians can better identify pot...

  4. Networked trafficking: reflections on technology and the anti-trafficking movement

    OpenAIRE

    boyd, danah; Thakor, Mitali Nitish

    2013-01-01

    In this essay, we offer field notes from our ongoing ethnographic research on sex trafficking in the United States. Recent efforts to regulate websites such as Craigslist and Backpage have illuminated activist concerns regarding the role of networked technologies in the trafficking of persons and images for the purposes of sexual exploitation. We frame our understanding of trafficking and technology through a network studies approach, by describing anti-trafficking as a counter-network to the...

  5. Clinical forensic medicine examination of trafficked victims

    Directory of Open Access Journals (Sweden)

    Alempijević Đorđe M.

    2004-01-01

    Full Text Available In this paper certain explanations of health related aspects of human trafficking are discussed together with responsibilities of health care providers to the victims of trafficking. Clinical forensic medicine is outlined, and its role in obtaining of medical evidence has been discussed. Special remarks are made on the application of clinical forensic medicine skills in assessment of victims of human trafficking. Protocol for clinical forensic examination of the victims of human trafficking, which has been developed in the Institute of Forensic Medicine in Belgrade, has been discussed in details.

  6. Phosphorylation-dependent Trafficking of Plasma Membrane Proteins in Animal and Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Remko Offringa; and Fang Huang

    2013-01-01

    In both unicellular and multicellular organisms, transmembrane (TM) proteins are sorted to and retained at specific membrane domains by endomembrane trafficking mechanisms that recognize sorting signals in the these proteins. The trafficking and distribution of plasma membrane (PM)-localized TM proteins (PM proteins), especially of those PM proteins that show an asymmetric distribution over the PM, has received much attention, as their proper PM localization is crucial for elementary signaling and transport processes, and defects in their localization often lead to severe disease symptoms or developmental defects. The subcellular localization of PM proteins is dynamically regulated by post-translational modifications, such as phosphorylation and ubiquitination. These modificaitons mostly occur on sorting signals that are located in the larger cytosolic domains of the cargo proteins. Here we review the effects of phosphorylation of PM proteins on their trafficking, and present the key examples from the animal field that have been subject to studies for already several decades, such as that of aquaporin 2 and the epidermal growth factor receptor. Our knowledge on cargo trafficking in plants is largely based on studies of the family of PIN FORMED (PIN) carriers that mediate the efflux of the plant hormone auxin. We will review what is known on the subcellular distribution and trafficking of PIN proteins, with a focus on how this is modulated by phosphorylation, and identify and discuss analogies and differences in trafficking with the well-studied animal examples.

  7. The effects of AMPA blockade on the spectral profile of human early visual cortex recordings studied with non-invasive MEG.

    Science.gov (United States)

    Muthukumaraswamy, Suresh D; Routley, Bethany; Droog, Wouter; Singh, Krish D; Hamandi, Khalid

    2016-08-01

    The generation of gamma-band (>30 Hz) cortical activity is thought to depend on the reciprocal connections of excitatory glutamatergic principal cells with inhibitory GABAergic interneurons. Both in vitro and in vivo animal studies have shown that blockade of glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors reduces the amplitude of gamma-band activity. In this registered report, we hypothesised that similar effects would be observed in humans following administration of perampanel, a first in class AMPA antagonist, used in the treatment of epilepsy. In a single-blind placebo-controlled crossover study, 20 healthy male participants completed two study days. On one day participants were given a 6 mg dose of perampanel and on the other an inactive placebo. magnetoencephalography (MEG) recordings of brain activity were taken before and two hours after drug administration, with activity in the visual cortex probed using a stimulation protocol known to induce gamma-band activity in the primary visual cortex. As hypothesised, our results indicated a decrease in gamma-band amplitudes following perampanel administration. The decreases in gamma-band amplitudes observed were temporally restricted to the early time-period of stimulus presentation (up to 400 msec) with no significant effects observed on early evoked responses or alpha rhythms. This suggests that the early time-window of induced visual gamma-band activity, thought to reflect input to the visual cortex from the lateral geniculate nucleus, is most sensitive to AMPA blocking drugs. PMID:27209006

  8. Scavenging ROS dramatically increase NMDA receptor whole-cell currents in painted turtle cortical neurons.

    Science.gov (United States)

    Dukoff, David James; Hogg, David William; Hawrysh, Peter John; Buck, Leslie Thomas

    2014-09-15

    Oxygen deprivation triggers excitotoxic cell death in mammal neurons through excessive calcium loading via over-activation of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. This does not occur in the western painted turtle, which overwinters for months without oxygen. Neurological damage is avoided through anoxia-mediated decreases in NMDA and AMPA receptor currents that are dependent upon a modest rise in intracellular Ca(2+) concentrations ([Ca(2+)]i) originating from mitochondria. Anoxia also blocks mitochondrial reactive oxygen species (ROS) generation, which is another potential signaling mechanism to regulate glutamate receptors. To assess the effects of decreased intracellular [ROS] on NMDA and AMPA receptor currents, we scavenged ROS with N-2-mercaptopropionylglycine (MPG) or N-acetylcysteine (NAC). Unlike anoxia, ROS scavengers increased NMDA receptor whole-cell currents by 100%, while hydrogen peroxide decreased currents. AMPA receptor currents and [Ca(2+)]i concentrations were unaffected by ROS manipulation. Because decreases in [ROS] increased NMDA receptor currents, we next asked whether mitochondrial Ca(2+) release prevents receptor potentiation during anoxia. Normoxic activation of mitochondrial ATP-sensitive potassium (mKATP) channels with diazoxide decreased NMDA receptor currents and was unaffected by subsequent ROS scavenging. Diazoxide application following ROS scavenging did not rescue scavenger-mediated increases in NMDA receptor currents. Fluorescent measurement of [Ca(2+)]i and ROS levels demonstrated that [Ca(2+)]i increases before ROS decreases. We conclude that decreases in ROS concentration are not linked to anoxia-mediated decreases in NMDA/AMPA receptor currents but are rather associated with an increase in NMDA receptor currents that is prevented during anoxia by mitochondrial Ca(2+) release.

  9. 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.

  10. Comparison on the Reception Property of Gunn Mounted ASRA and AMPA

    Directory of Open Access Journals (Sweden)

    Somnath Chatterjee

    2013-08-01

    Full Text Available A Gunn mounted active microstrip patch antenna (AMPA and active microstrip slot antenna (ASRA has been investigated for the reception of FM microwave signal. Current well/valley phenomenon has been successfully utilized to demodulate the modulation information. Reception poperty of the both antennas are studied in multi-channel environment. Because of its simple circuit configuration and similarity in transmitter and receiver architecture, active patch antenna as demonstrated is well suited for commercial and military application as a two-way microwave communication system. A comparative study on the role of AMPA and ASRA as a receiver shows that ASRA do better performances than AMPA. In case of ASRA the modulating signal are demodulated without any distortion. ASRA also has large locking range (29 MHz compare to AMPA (5 MHz. So the ASRA has broad band tuning capabilities than AMPA. With ASRA configuration demodulation bandwidth in excess of 14 MHz is realizable which can successfully accommodate a large number of voice or data channels.

  11. HUMAN TRAFFICKING: THE BAHRAIN EXPERIENCE

    OpenAIRE

    Ali Al JABAL

    2010-01-01

    Drug smuggling may top the list of the world’s most profitable and headline-grabbing illegal activities, but second to that —in a close tie with the illegal arms trade — is human trafficking, the recruitment or coercion of people who are held captive as laborers in everything from the sex industry to domestic servitude. More than 12 million people worldwide are currently victims, according to the United Nations' International Labor Organization. The $9 billion industry is the 21st century’s f...

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

    International Nuclear Information System (INIS)

    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

  13. Preliminary Validation of the Sex Trafficking Attitudes Scale.

    Science.gov (United States)

    Houston-Kolnik, Jaclyn D; Todd, Nathan R; Wilson, Midge

    2016-09-01

    This study presents the Sex Trafficking Attitudes Scale (STAS), assessing cognitive, behavioral, and affective attitudes toward the sex trafficking of women and girls. Across two studies, exploratory and confirmatory factor analyses revealed and confirmed six subscales: (a) Knowledge About Sex Trafficking, (b) Awareness of Sex Trafficking, (c) Attitudes Toward Ability to Leave Sex Trafficking, (d) Attitudes Toward Helping Survivors, (e) Empathic Reactions Toward Sex Trafficking, and (f) Efficacy to Reduce Sex Trafficking. Results showed support for convergent validity as the subscales were associated with related measures. The STAS holds promise to expand research and inform efforts to support trafficking survivors.

  14. A Proteomics Approach to Membrane Trafficking

    NARCIS (Netherlands)

    Groen, A.J.; Vries, de S.C.; Lilley, K.S.

    2008-01-01

    Membrane trafficking, including that of integral membrane proteins as well as peripherally associated proteins, appears to be a vital process common to all eukaryotes. An important element of membrane trafficking is to determine the protein composition of the various endomembrane compartments. A maj

  15. 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...

  16. Functional Insights from Glutamate Receptor Ion Channel Structures

    Science.gov (United States)

    Kumar, Janesh; Mayer, Mark L.

    2014-01-01

    X-ray crystal structures for the soluble amino terminal and ligand binding domains of glutamate receptor ion channels, combined with a 3.6 Å resolution structure of the full length AMPA receptor GluA2 homotetramer, provide unique insights into the mechanisms of iGluR assembly and function. Increasingly sophisticated biochemical, computational and electrophysiological experiments are beginning to reveal the mechanism of action of partial agonists, and yield new models for the mechanism of action of allosteric modulators. Newly identified NMDA receptor ligands acting at novel sites offer hope for development of subtype selective modulators. Many issues remain unsolved, including the role of the ATD in AMPA receptor signaling, and the mechanisms by which auxiliary proteins regulate receptor activity. The structural basis for ion permeation and ion channel block also remain areas of uncertainty, and despite substantial progress, molecular dynamics simulations have yet to reveal how binding of glutamate opens the ion channel pore. PMID:22974439

  17. Examining the Risk of Nuclear Trafficking

    Energy Technology Data Exchange (ETDEWEB)

    Balatsky, Galya [Los Alamos National Laboratory; Severe, William R [Los Alamos National Laboratory; Schoeneck, Jeffery [DHS

    2009-01-01

    The need to stop illicit trafficking of nuclear and radioactive materials around the world is undeniable and urgent. This issue is particularly evident due to the highly dangerous consequences of the risks involved, the known interest of terrorist groups in acquiring such materials and the vulnerability of theft and diversion of such materials. Yet the phenomenon of nuclear trafficking remains a subject where the unknown dominates what is known on the subject. The trafficking panel at the Institute for Nuclear Materials Management (INMM) Workshop on Reducing the Risk of Radioactive and Nuclear Materials that took place in Albuquerque, New Mexico, March 10-11, 2009, dealt with some of the issues associated with nuclear trafficking. Different points of view on how to better address trafficking and thwart perpetrator efforts were discussed. This paper presents some of these views and addresses practical measures that should be considered to improve the situation.

  18. 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)

  19. Tracking Traffickers. The IAEA Incident and Trafficking Database

    International Nuclear Information System (INIS)

    Radioactive material is missing from a hospital. Contaminated metal is found in a scrap yard. Smugglers try to peddle nuclear- weapon-usable material. These different scenarios illustrate the risks that these materials can pose to human safety and security. To assess those risks and to develop strategies to reduce them, States must understand the implications and the scope of such incidents that are occurring around the world. To better understand and respond to these events, the IAEA maintains an Incident and Trafficking Database (ITDB) which collects information from 122 participating States and some select international organizations. They are asked to share data on a voluntary basis about incidents in which nuclear and other radioactive material has fallen ''out of regulatory control.'' This could mean reporting cases of material that has gone missing, or discoveries of material where none was expected. The cases range from the innocent misplacement of industrial radioactive sources to criminal smuggling efforts which could aid terrorist acts. This information is shared among ITDB participants, and IAEA analysts try to identify trends and characteristics that could help prevent the misuse of these potentially dangerous materials. ''The ITDB has become an internationally recognized tool for States to study the extent and nature of these incidents,'' said John Hilliard, head of the Information Management and Coordination Section that administers the database. ''We've learned a lot by studying them, and we hope the information helps us prevent accidents or crimes in the future.'' The IAEA established the database in 1995 after States became alarmed by a growing number of trafficking incidents in the early 1990s. The service was originally operated by the Department of Safeguards, but later moved to the Department of Nuclear Safety and Security, where the Office of Nuclear Security now administers all the data collection and analysis

  20. Mitochondrial superoxide production and MnSOD activity following exposure to an agonist and antagonists of ionotropic receptors in rat brain

    Directory of Open Access Journals (Sweden)

    Radenović Lidija Lj.

    2005-01-01

    Full Text Available The involvement of NMDA and AMPA/kainate receptors in the induction of superoxide production in the rat brain was examined after intrahippocampal injection of kainate, a non-NMDA receptor agonist; kainate plus CNQX, a selective AMPA/kainate receptor antagonist; or kainate plus APV, a selective NMDA receptor antagonist. The measurements took place at different times in the ipsi- and contralateral hippocampus, forebrain cortex, striatum, and cerebellum homogenates. The used glutamate antagonists both ensured sufficient neuroprotection in the sense of lowering superoxide production and raising MnSOD levels, but in the mechanisms and time dynamics of their effects were different. Our findings suggest that NMDA and AMPA/kainate receptors are differentially involved in superoxide production. UDC 612.815 612.82.

  1. Pharmacological analysis of ionotropic glutamate receptor function in neuronal circuits of the zebrafish olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Rico Tabor

    Full Text Available Although synaptic functions of ionotropic glutamate receptors in the olfactory bulb have been studied in vitro, their roles in pattern processing in the intact system remain controversial. We therefore examined the functions of ionotropic glutamate receptors during odor processing in the intact olfactory bulb of zebrafish using pharmacological manipulations. Odor responses of mitral cells and interneurons were recorded by electrophysiology and 2-photon Ca(2+ imaging. The combined blockade of AMPA/kainate and NMDA receptors abolished odor-evoked excitation of mitral cells. The blockade of AMPA/kainate receptors alone, in contrast, increased the mean response of mitral cells and decreased the mean response of interneurons. The blockade of NMDA receptors caused little or no change in the mean responses of mitral cells and interneurons. However, antagonists of both receptor types had diverse effects on the magnitude and time course of individual mitral cell and interneuron responses and, thus, changed spatio-temporal activity patterns across neuronal populations. Oscillatory synchronization was abolished or reduced by AMPA/kainate and NMDA receptor antagonists, respectively. These results indicate that (1 interneuron responses depend mainly on AMPA/kainate receptor input during an odor response, (2 interactions among mitral cells and interneurons regulate the total olfactory bulb output activity, (3 AMPA/kainate receptors participate in the synchronization of odor-dependent neuronal ensembles, and (4 ionotropic glutamate receptor-containing synaptic circuits shape odor-specific patterns of olfactory bulb output activity. These mechanisms are likely to be important for the processing of odor-encoding activity patterns in the olfactory bulb.

  2. Nuclear trafficking latest statistics released

    International Nuclear Information System (INIS)

    Full text: Countries reported 121 incidents to the IAEA in 2004 of illicit trafficking and other unauthorized activities involving nuclear and other radioactive materials, newly released statistics from the Agency's Illicit Trafficking Database (ITDB) show. The ITDB report also shows that one incident was reported since 2003 that involved fissile material - highly enriched uranium (HEU) or plutonium - that is needed to make a nuclear weapon. It occurred in June 2003 when an individual was arrested in possession of 170 grams of HEU, attempting to illegally transport it across the border. During the two-year period 2003-2004, the number of incidents reported by States substantially increased compared with previous years. 'Improved reporting may in part account for it,' the report said. 'The majority of the incidents reported in 2003-2004 showed no evidence of criminal activity.' The Past Twelve Years: 1993 - 2004 Nuclear Weapons Grade Material. Since the database started in 1993, there have been eighteen confirmed incidents involving trafficking in HEU and plutonium. A few of these incidents involved seizures of kilogram quantities of weapons-usable nuclear material but most involved very small quantities. In some of the cases the seized material was allegedly a sample of larger quantities available for illegal sale or at risk of theft. More than two dozens incidents involved trace amounts of plutonium sources. Table can be viewed: Incidents involving HEU and Pu confirmed to the ITDB (1993-2004). Nuclear Materials. In the past twelve years, 220 incidents involved nuclear materials. The majority of confirmed cases with nuclear materials involved low-grade nuclear materials, mostly in the form of reactor fuel pellets, and natural uranium, depleted uranium and thorium. While the quantities of these materials have been rather small to be significant for nuclear proliferation or use in a terrorist nuclear explosive device, these cases are indicative of gaps in the control

  3. 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”.

  4. Do Public Events Affect Sex Trafficking Activity?

    OpenAIRE

    MILLER, KYLE; Kennedy, Emily; Dubrawski, Artur

    2016-01-01

    For several years the pervasive belief that the Super Bowl is the single biggest day for human trafficking in the United States each year has been perpetuated in popular press despite a lack of evidentiary support. The practice of relying on hearsay and popular belief for decision-making may result in misappropriation of resources in anti-trafficking efforts. We propose a data-driven approach to analyzing sex trafficking, especially as it is carried on during--and perhaps in response to--larg...

  5. 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

    The excitotoxic profiles of (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propionic acid (ATPA), (RS)-2-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), kainic acid (KA) and N-methyl-D-aspartate (NMDA) were evaluated using cellular uptake of propidium iodide (PI) as a measure for...

  6. Female sex trafficking: conceptual issues, current debates, and future directions.

    Science.gov (United States)

    Meshkovska, Biljana; Siegel, Melissa; Stutterheim, Sarah E; Bos, Arjan E R

    2015-01-01

    Female sex trafficking is a pressing concern. In this article, we provide a comprehensive overview of relevant issues regarding the concept of female sex trafficking and research in the field of human trafficking, drawing on a variety of disciplines, including economics, gender and sexuality studies, psychology, sociology, law, and social work. We discuss the debates surrounding the definition of human trafficking, compare and contrast it with human smuggling, and outline connections between female sex trafficking and the issue of sex work and prostitution. We further discuss the history and current estimations of female sex trafficking. We then outline the main actors in female sex trafficking, including trafficked persons, traffickers, clients, and service providers, and we overview the trafficking process from recruitment to identification, recovery, and (re)integration. Finally, we conclude with recommendations for future research that tie together the concepts of vulnerability, exploitation, and long-term recovery and (re)integration. PMID:25897567

  7. Transnational trafficking, law enforcement and victim protection: A middleman trafficker's perspective

    OpenAIRE

    Akee, Randall K. Q.; Bedi, Arjun S.; Basu, Arnab K.; Chau, Nancy

    2011-01-01

    We explore three hitherto poorly understood characteristics of the human trafficking market – the cross-border ease of mobility of traffickers, the relative bargaining strength of traffickers and final buyers, and the elasticity of buyers' demand. In a model of two-way bargaining, the exact configuration of these characteristics is shown to determine whether domestic and foreign crackdowns on illicit employment mutually reinforce or counteract one another in efforts to stem the tide of traffi...

  8. Human trafficking in Asia: a heinous crime against humanities

    OpenAIRE

    Mohajan, Haradhan

    2012-01-01

    This paper discusses the human trafficking especially women and children trafficking in Asia. Human trafficking is not only a local problem but also a global concern. It is performed for various purposes such as labor, prostitution, organ transplant, drug couriers, and arm smuggling and affects virtually every country in the world. Recently trafficking of human being increased alarmingly due to globalization and liberalization. In Bangladesh and Nepal trafficking becomes an important issue re...

  9. European penal law - an instrument to fight against human trafficking

    OpenAIRE

    Ada-Iuliana POPESCU

    2009-01-01

    Human trafficking has become one of the most versatile and hard to combat social phenomenon. Coordination of national action plans and legislative harmonization are vital for preventing traffick-ing, punishing traffickers and protecting victims. Even though national legal rules concerning human trafficking are similar, regional circumstances have to be taken into account, adapting these rules ac-cordingly. Uniform criminal rules could be one solution to prevent and successfully combat transna...

  10. Intracellular calcium release modulates polycystin-2 trafficking

    Directory of Open Access Journals (Sweden)

    Miyakawa Ayako

    2013-02-01

    Full Text Available Abstract Background Polycystin-2 (PC2, encoded by the gene that is mutated in autosomal dominant polycystic kidney disease (ADPKD, functions as a calcium (Ca2+ permeable ion channel. Considerable controversy remains regarding the subcellular localization and signaling function of PC2 in kidney cells. Methods We investigated the subcellular PC2 localization by immunocytochemistry and confocal microscopy in primary cultures of human and rat proximal tubule cells after stimulating cytosolic Ca2+ signaling. Plasma membrane (PM Ca2+ permeability was evaluated by Fura-2 manganese quenching using time-lapse fluorescence microscopy. Results We demonstrated that PC2 exhibits a dynamic subcellular localization pattern. In unstimulated human or rat proximal tubule cells, PC2 exhibited a cytosolic/reticular distribution. Treatments with agents that in various ways affect the Ca2+ signaling machinery, those being ATP, bradykinin, ionomycin, CPA or thapsigargin, resulted in increased PC2 immunostaining in the PM. Exposing cells to the steroid hormone ouabain, known to trigger Ca2+ oscillations in kidney cells, caused increased PC2 in the PM and increased PM Ca2+ permeability. Intracellular Ca2+ buffering with BAPTA, inositol 1,4,5-trisphosphate receptor (InsP3R inhibition with 2-aminoethoxydiphenyl borate (2-APB or Ca2+/Calmodulin-dependent kinase inhibition with KN-93 completely abolished ouabain-stimulated PC2 translocation to the PM. Conclusions These novel findings demonstrate intracellular Ca2+-dependent PC2 trafficking in human and rat kidney cells, which may provide new insight into cyst formations in ADPKD.

  11. Human trafficking law and social structures.

    Science.gov (United States)

    Wooditch, Alese

    2012-08-01

    Human trafficking has only recently emerged at the forefront of policy reform, even in developed nations. Yet, heightened awareness of the issue has not translated into effective policy as the majority of nations have ineffective antitrafficking practices; many countries have failed to criminalize human trafficking, whereas others do not actively enforce statutes in place. By applying Black's theory of law, this study offers a preliminary understanding into the variation of global prosecutorial efforts in human trafficking and adequacy of antitrafficking law. To isolate this relationship, the effects of trafficking markets are controlled. As with prior research, the study finds limited support for the theory. The article concludes with a discussion on the implications of the quantity of antitrafficking law and morphology association for policy development.

  12. Committee opinion no. 507: human trafficking.

    Science.gov (United States)

    2011-09-01

    Human trafficking is a widespread problem with estimates ranging from 14,000 to 50,000 individuals trafficked into the United States annually. This hidden population involves the commercial sex industry, agriculture, factories, hotel and restaurant businesses, domestic workers, marriage brokers, and some adoption firms. Because 80% of trafficked individuals are women and girls, women’s health care providers may better serve their diverse patient population by increasing their awareness of this problem. The exploitation of people of any race, gender, sexual orientation, or ethnicity is unacceptable at any time, in any place. The members of the American College of Obstetricians and Gynecologists should be aware of this problem and strive to recognize and assist their patients who are victims or who have been victims of human trafficking. PMID:21860320

  13. Sex trafficking of women and girls.

    Science.gov (United States)

    Deshpande, Neha A; Nour, Nawal M

    2013-01-01

    Sex trafficking involves some form of forced or coerced sexual exploitation that is not limited to prostitution, and has become a significant and growing problem in both the United States and the larger global community. The costs to society include the degradation of human and women's rights, poor public health, disrupted communities, and diminished social development. Victims of sex trafficking acquire adverse physical and psychological health conditions and social disadvantages. Thus, sex trafficking is a critical health issue with broader social implications that requires both medical and legal attention. Healthcare professionals can work to improve the screening, identification, and assistance of victims of sex trafficking in a clinical setting and help these women and girls access legal and social services. PMID:23687554

  14. Ovarian Cystadenoma in a Trafficked Patient.

    Science.gov (United States)

    Titchen, Kanani E; Katz, Douglas; Martinez, Kidian; White, Krishna

    2016-05-01

    The topic of child sex trafficking is receiving increased attention both in the lay press and in research articles. Recently, a number of physician organizations have issued policy statements calling for the education and involvement of physicians in combating this form of "modern-day slavery." Primary care and emergency medicine physicians have led these efforts, but a number of these victims may present to surgeons. Surgeons are in a unique position to identify trafficked patients; during the process of undraping, intubation, and surgical preparation, signs of trafficking such as tattoos, scars, dental injuries, and bruising may be evident. In addition, these patients may have specific needs in terms of anesthesia and postoperative care due to substance abuse. Here, we report the case of an 18-year-old girl with a history of sexual exploitation who presents for cystadenoma excision. To our knowledge, this is the first report of a sex-trafficked pediatric patient presenting for surgery. PMID:27244785

  15. Modeling for Determinants of Human Trafficking

    OpenAIRE

    Cho, Seo-Young

    2012-01-01

    This study aims to identify robust push and pull factors of human trafficking. I test for the robustness of 78 push and 67 pull factors suggested in the literature. By employing an extreme bound analysis, running more than two million regressions with all possible combinations of variables for up to 180 countries during the period of 1995-2010, I show that crime prevalence robustly explains human trafficking prevalence both in destination and origin countries. My finding also implies that a l...

  16. Liberal coercion? Prostitution, human trafficking and policy

    OpenAIRE

    Cho, Seo-Young

    2013-01-01

    Liberal prostitution policy aims at improving labour conditions for prostitutes and protecting victims of forced prostitution. Its policy orientation predicts that the policy choice of liberalizing prostitution is positively associated with better protection policy for trafficking victims and enhanced anti-trafficking measures. In this paper, I investigate empirically whether the legalization of prostitution improves protection policy for victims, as it is presumed. The results of my analysis...

  17. Human Trafficking: The Shameful Face of Migration

    OpenAIRE

    2011-01-01

    In the June editorial, the PLoS Medicine Editors highlight the global importance, impact, and health implications of trafficking in persons. This editorial is part of the PLoS Medicine Series on Migration and Health (http://www.ploscollections.org/migrationhealth). The editors argue that despite internationally agreed policies outlining states' responsibilities to protect those affected by trafficking, many countries lack the political will to establish those protections.

  18. Organ trading, tourism, and trafficking within Europe.

    OpenAIRE

    Pattinson, Shaun D.

    2008-01-01

    This article argues for a regulatory and institutional response towards organ trading, tourism and trafficking that differs from extant approaches. European countries have hitherto adopted blanket prohibitions on organ trading (i.e. the buying or selling of human organs). This article advances the view that policy makers have thereby overreacted to legitimate public health concerns and the evils of organ trafficking (i.e. organ trad-ing and tourism involving coercion or deception). It argues ...

  19. Critically Analyzing Issues in Human Trafficking

    OpenAIRE

    Price, Alani

    2008-01-01

    Like me, many people may at first glance gloss over the popular images and rhetoric of human trafficking as an “easy” moral judgment. Upon examination, however, issues of globalization, immigration, law enforcement, gender roles, and controversial legal definitions make human trafficking an extremely complex tragedy-one that defies generalization and, within the political reality of international and national laws, is often conflated with otherinterests such as state control of immigration or...

  20. Illegal immigration, human trafficking, and organized crime

    OpenAIRE

    Väyrynen, Raimo

    2003-01-01

    It is important to make a careful distinction between illegal immigration, human smuggling, and human trafficking which are nested, but yet different concepts. This distinction is relevant because these different categories of the illegal movement of people across borders have quite different legal and political consequences. Human smuggling and trafficking have become a world-wide industry that ‘employs’ every year millions of people and leads to the annual turnover of billions of dollars. M...

  1. Trafficking Networks and the Mexican Drug War

    OpenAIRE

    Melissa

    2015-01-01

    Drug trade-related violence has escalated dramatically in Mexico since 2007, and recent years have also witnessed large-scale efforts to combat trafficking, spearheaded by Mexico's conservative PAN party. This study examines the direct and spillover effects of Mexican policy toward the drug trade. Regression discontinuity estimates show that drug-related violence increases substantially after close elections of PAN mayors. Empirical evidence suggests that the violence reflects rival trafficke...

  2. Trafficking of Dopamine Transporters in Psychostimulant Actions

    OpenAIRE

    Zahniser, Nancy R.; Sorkin, Alexander

    2009-01-01

    Brain dopamine (DA) plays a pivotal role in drug addiction. Since the plasma membrane DA transporter (DAT) is critical for terminating DA neurotransmission, it is important to understand how DATs are regulated and this regulation impacts drug addiction. The number of cell surface DATs is controlled by constitutive and regulated endocytic trafficking. Psychostimulants impact this trafficking. Amphetamines, DAT substrates, cause rapid up-regulation and slower down-regulation of DAT whereas coca...

  3. Exploring the GluR2 ligand-binding core in complex with the bicyclical AMPA analogue (S)-4-AHCP

    DEFF Research Database (Denmark)

    Nielsen, Bettina B; Pickering, Darryl S; Greenwood, Jeremy R;

    2005-01-01

    The X-ray structure of the ionotropic GluR2 ligand-binding core (GluR2-S1S2J) in complex with the bicyclical AMPA analogue (S)-2-amino-3-(3-hydroxy-7,8-dihydro-6H-cyclohepta[d]-4-isoxazolyl)propionic acid [(S)-4-AHCP] has been determined, as well as the binding pharmacology of this construct...... and of the full-length GluR2 receptor. (S)-4-AHCP binds with a glutamate-like binding mode and the ligand adopts two different conformations. The K(i) of (S)-4-AHCP at GluR2-S1S2J was determined to be 185 +/- 29 nM and at full-length GluR2(R)o it was 175 +/- 8 nM. (S)-4-AHCP appears to elicit partial agonism...... at GluR2 by inducing an intermediate degree of domain closure (17 degrees). Also, functionally (S)-4-AHCP has an efficacy of 0.38 at GluR2(Q)i, relative to (S)-glutamate. The proximity of bound (S)-4-AHCP to domain D2 prevents full D1-D2 domain closure, which is limited by steric repulsion, especially...

  4. RNA trafficking in parasitic plant systems

    Directory of Open Access Journals (Sweden)

    Megan L LeBlanc

    2012-08-01

    Full Text Available RNA trafficking in plants contributes to local and long-distance coordination of plant development and response to the environment. However, investigations of mobile RNA identity and function are hindered by the inherent difficulty of tracing a given molecule of RNA from its cell of origin to its destination. Several methods have been used to address this problem, but all are limited to some extent by constraints associated with accurately sampling phloem sap or detecting trafficked RNA. Certain parasitic plant species form symplastic connections to their hosts and thereby provide an additional system for studying RNA trafficking. The haustorial connections of Cuscuta and Phelipanche species are similar to graft junctions in that they are able to transmit mRNAs, viral RNAs, siRNAs and proteins from the host plants to the parasite. In contrast to other graft systems, these parasites form connections with host species that span a wide phylogenetic range, such that a high degree of nucleotide sequence divergence may exist between host and parasites and allow confident identification of most host RNAs in the parasite system. The ability to identify host RNAs in parasites, and vice versa, will facilitate genomics approaches to understanding RNA trafficking. This review discusses the nature of host parasite connections and the potential significance of host RNAs for the parasite. Additional research on host-parasite interactions is needed to interpret results of RNA trafficking studies, but parasitic plants may provide a fascinating new perspective on RNA trafficking.

  5. The hidden crime: human trafficking.

    Science.gov (United States)

    Clause, Kristen J; Lawler, Kate Byrnes

    2013-01-01

    As the primary contact in the health care system, nurses can play a role in combating this crime and assisting the victims. Assessment for abuse, neglect, trauma, recurrent sexually transmitted infections (STIs) and fear of a controlling partner is critical. Following up on "red flags" and understanding methods of safe questioning can make the difference between slavery and recovery for victims. Nurses must also know the professional referrals in their areas once a potential victim has been identified. This may be a very dangerous undertaking and must be handled by experienced personnel. Referrals to forensic nurses or physicians, domestic violence professionals or law enforcement may be indicated. Initially, a nurse may want to consult with the agency social worker for guidance. Human trafficking is a human rights crime. Unfortunately, it is more prevalent in all types of communities than most people suspect. Nurses can be heroes to the victims through understanding of this crime and vigilance in the assessment and care of all people they encounter in their practices.

  6. Metabotropic glutamate receptors depress vagal and aortic baroreceptor signal transmission in the NTS.

    Science.gov (United States)

    Liu, Z; Chen, C Y; Bonham, A C

    1998-11-01

    We sought to determine whether metabotropic glutamate receptors contribute to frequency-dependent depression of vagal and aortic baroreceptor signal transmission in the nucleus of the solitary tract (NTS) in vivo. In alpha-chloralose-anesthetized rabbits, we determined the number of extracellular action potentials synaptically evoked by low (1 Hz)- or high-frequency vagal (3-20 Hz) or aortic depressor nerve (ADN) (6-80 Hz) stimulation and postsynaptically evoked by the ionotropic glutamate receptor agonist alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). The metabotropic glutamate receptor agonist (2S,1'S, 2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I) attenuated NTS responses monosynaptically evoked by 1-Hz vagus stimulation by 34% (n = 25; P = 0.011), while augmenting AMPA-evoked responses by 64% (n = 17; P = 0.026). The metabotropic glutamate receptor antagonist alpha-methyl-4-phosphonophenylglycine (MPPG) did not affect NTS responses to low-frequency vagal stimulation (n = 11) or AMPA (n = 10) but augmented responses to high-frequency stimulation by 50% (n = 25; P = 0.0001). MPPG also augmented NTS responses to high-frequency ADN stimulation by 35% (n = 9; P = 0.048) but did not affect responses to low-frequency stimulation (n = 9) or AMPA (n = 7). The results suggest that metabotropic glutamate receptors, presumably at presynaptic sites, contribute to frequency-dependent depression of vagal and aortic baroreceptor signal transmission in NTS. PMID:9815076

  7. A High-Dimensional Atlas of Human T Cell Diversity Reveals Tissue-Specific Trafficking and Cytokine Signatures.

    Science.gov (United States)

    Wong, Michael Thomas; Ong, David Eng Hui; Lim, Frances Sheau Huei; Teng, Karen Wei Weng; McGovern, Naomi; Narayanan, Sriram; Ho, Wen Qi; Cerny, Daniela; Tan, Henry Kun Kiaang; Anicete, Rosslyn; Tan, Bien Keem; Lim, Tony Kiat Hon; Chan, Chung Yip; Cheow, Peng Chung; Lee, Ser Yee; Takano, Angela; Tan, Eng-Huat; Tam, John Kit Chung; Tan, Ern Yu; Chan, Jerry Kok Yen; Fink, Katja; Bertoletti, Antonio; Ginhoux, Florent; Curotto de Lafaille, Maria Alicia; Newell, Evan William

    2016-08-16

    Depending on the tissue microenvironment, T cells can differentiate into highly diverse subsets expressing unique trafficking receptors and cytokines. Studies of human lymphocytes have primarily focused on a limited number of parameters in blood, representing an incomplete view of the human immune system. Here, we have utilized mass cytometry to simultaneously analyze T cell trafficking and functional markers across eight different human tissues, including blood, lymphoid, and non-lymphoid tissues. These data have revealed that combinatorial expression of trafficking receptors and cytokines better defines tissue specificity. Notably, we identified numerous T helper cell subsets with overlapping cytokine expression, but only specific cytokine combinations are secreted regardless of tissue type. This indicates that T cell lineages defined in mouse models cannot be clearly distinguished in humans. Overall, our data uncover a plethora of tissue immune signatures and provide a systemic map of how T cell phenotypes are altered throughout the human body. PMID:27521270

  8. A High-Dimensional Atlas of Human T Cell Diversity Reveals Tissue-Specific Trafficking and Cytokine Signatures.

    Science.gov (United States)

    Wong, Michael Thomas; Ong, David Eng Hui; Lim, Frances Sheau Huei; Teng, Karen Wei Weng; McGovern, Naomi; Narayanan, Sriram; Ho, Wen Qi; Cerny, Daniela; Tan, Henry Kun Kiaang; Anicete, Rosslyn; Tan, Bien Keem; Lim, Tony Kiat Hon; Chan, Chung Yip; Cheow, Peng Chung; Lee, Ser Yee; Takano, Angela; Tan, Eng-Huat; Tam, John Kit Chung; Tan, Ern Yu; Chan, Jerry Kok Yen; Fink, Katja; Bertoletti, Antonio; Ginhoux, Florent; Curotto de Lafaille, Maria Alicia; Newell, Evan William

    2016-08-16

    Depending on the tissue microenvironment, T cells can differentiate into highly diverse subsets expressing unique trafficking receptors and cytokines. Studies of human lymphocytes have primarily focused on a limited number of parameters in blood, representing an incomplete view of the human immune system. Here, we have utilized mass cytometry to simultaneously analyze T cell trafficking and functional markers across eight different human tissues, including blood, lymphoid, and non-lymphoid tissues. These data have revealed that combinatorial expression of trafficking receptors and cytokines better defines tissue specificity. Notably, we identified numerous T helper cell subsets with overlapping cytokine expression, but only specific cytokine combinations are secreted regardless of tissue type. This indicates that T cell lineages defined in mouse models cannot be clearly distinguished in humans. Overall, our data uncover a plethora of tissue immune signatures and provide a systemic map of how T cell phenotypes are altered throughout the human body.

  9. Aestivation and hypoxia-related events share common silent neuron trafficking processes

    Directory of Open Access Journals (Sweden)

    Giusi Giuseppina

    2012-04-01

    Full Text Available Abstract Background The availability of oxygen is a limiting factor for neuronal survival since low levels account not only for the impairment of physiological activities such as sleep-wake cycle, but above all for ischemic-like neurodegenerative disorders. In an attempt to improve our knowledge concerning the type of molecular mechanisms operating during stressful states like those of hypoxic conditions, attention was focused on eventual transcriptional alterations of some key AMPAergic silent neuronal receptor subtypes (GluR1 and GluR2 along with HSPs and HIF-1α during either a normoxic or a hypoxic aestivation of a typical aquatic aestivator, i.e. the lungfish (Protopterus annectens. Results The identification of partial nucleotide fragments codifying for both AMPA receptor subtypes in Protopterus annectens displayed a putative high degree of similarity to that of not only fish but also to those of amphibians, birds and mammals. qPCR and in situ hybridization supplied a very high (p p  Conclusions The distinct transcriptional variations of silent neurons expressing GluR1/2 and HSPs tend to corroborate these factors as determining elements for the physiological success of normoxic and hypoxic aestivation. A distinct switching among these AMPA receptor subtypes during aestivation highlights new potential adaptive strategies operating in key brain regions of the lungfish in relation to oxygen availability. This functional relationship might have therapeutic bearings for hypoxia-related dysfunctions, above all in view of recently identified silent neuron-dependent motor activity ameliorations in mammals.

  10. 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...

  11. 'Effective inefficiency': cellular control of protein trafficking as a mechanism of post-translational regulation.

    Science.gov (United States)

    Conn, P Michael; Janovick, Jo Ann; Brothers, Shaun P; Knollman, Paul E

    2006-07-01

    The great writer and polyglot, W Somerset Maugham said, 'I'll give you my opinion of the human race in a nutshell...their heart's in the right place, but their head is a thoroughly inefficient organ.' If his words are applied to trafficking of the human pituitary gonadotropin-releasing hormone receptor, it turns out that he was more right than he knew. Paradoxically, the inefficiency of receptor trafficking to the plasma membrane can bring regulatory advantages to cells. Understanding the mechanism by which cells recognize correctly folded proteins in health and disease opens doors to new therapeutic approaches and provides a more accurate view of mechanisms of normal cell function than is presently available. PMID:16837606

  12. Checking the STEP-Associated Trafficking and Internalization of Glutamate Receptors for Reduced Cognitive Deficits: A Machine Learning Approach-Based Cheminformatics Study and Its Application for Drug Repurposing.

    Directory of Open Access Journals (Sweden)

    Salma Jamal

    Full Text Available Alzheimer's disease, a lethal neurodegenerative disorder that leads to progressive memory loss, is the most common form of dementia. Owing to the complexity of the disease, its root cause still remains unclear. The existing anti-Alzheimer's drugs are unable to cure the disease while the current therapeutic options have provided only limited help in restoring moderate memory and remain ineffective at restricting the disease's progression. The striatal-enriched protein tyrosine phosphatase (STEP has been shown to be involved in the internalization of the receptor, N-methyl D-aspartate (NMDR and thus is associated with the disease. The present study was performed using machine learning algorithms, docking protocol and molecular dynamics (MD simulations to develop STEP inhibitors, which could be novel anti-Alzheimer's molecules.The present study deals with the generation of computational predictive models based on chemical descriptors of compounds using machine learning approaches followed by substructure fragment analysis. To perform this analysis, the 2D molecular descriptors were generated and machine learning algorithms (Naïve Bayes, Random Forest and Sequential Minimization Optimization were utilized. The binding mechanisms and the molecular interactions between the predicted active compounds and the target protein were modelled using docking methods. Further, the stability of the protein-ligand complex was evaluated using MD simulation studies. The substructure fragment analysis was performed using Substructure fingerprint (SubFp, which was further explored using a predefined dictionary.The present study demonstrates that the computational methodology used can be employed to examine the biological activities of small molecules and prioritize them for experimental screening. Large unscreened chemical libraries can be screened to identify potential novel hits and accelerate the drug discovery process. Additionally, the chemical libraries can be

  13. FERMENTASI CAIR AMPAS KELAPA SAWIT DAN KAPANG RHIZOPUS OLIGOSPORUS UNTUK MENGHASILKAN ASAM LEMAK OMEGA-3

    Directory of Open Access Journals (Sweden)

    Erwin Affandi

    2012-11-01

    :1, linoleic acid (18:2 and linolenic (18:3 increased. However, all fatty acid in low-carbon treatment decreased, except the linolenic-acid. The conclusion: The fermentation of palm-oil waste with Rhizopus oligosporus mold could increase the content of fat and produce fatty acid omega-3.   In addition, the high-carbon substrat could increase the production of unsaturated-fatty acid.  Submit : 19-12-2011  Review : 08-03-2012 Review : 12 -03-2012 revisi : 17–4-2012 56 Keywords: liquefied-fermentation, waste product of palm oil, R.oligosporus, fatty acid 0mega-3 Abstrak Latar belakang: Pemanfaatan kapang Rhizopus. oligosporus untuk menghasilkan asam lemak omega-3 pada substrat cair telah banyak dilakukan. Kandungan lemak ampas kelapa sawit 5,56 gram/100 gram masih berpotensi untuk menghasilkan asam lemak omega-3. Fermentasi padat pada substrat ampas tahu dan ampas kelapa sawit dengan kapang Rhizopus. oligosporus dapat meningkatkan kadar lemak: ampas tahu 34,4%, sedangkan pada substrat ampas kelapa sawit dengan formula tinggi karbon, kadar lemak meningkat 61,57%. Metoda: Sampel ampas sawit diambil dari pabrik industri minyak sawit. Pada penelitian ini ampas sawit dipakai sebagai substrat fermentasi dan kapang yang digunakan adalah R.oligosporus. Untuk bahan suplemen digunakan urea dan sukrosa Kontrol adalah ampas-sawit tanpa suplemen, sedangkan perlakuan ampas sawit ditambahkan urea sebagai sumber Nitrogen(N dan ampas sawit ditambah sukrosa sebagai sumber Karbon(C. Penambahan sumber N sebagai substrat rendah karbon dan sumber C sebagai substrat tinggi karbon. Fermentasi dilakukan selama 7 hari diatas shaker pada suhu ruang.  Produk hasil fermentasi dilakukan analisis: kadar air; abu, lemak, dan asam lemak omega-3. Hasil penelitian: Hasil menunjukkan bahwa kadar air  produk hasil fermentasi menurun pada kontrol dan semua perlakuan. Kadar abu meningkat untuk semua perlakuan. Kandungan lemak pada ampas kontrol dan ampas-sukrosa  meningkat 6,43% dan 31,67%, sedang substrat

  14. 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

    -sulphamoylbenzo-[f]-quinoxaline-2,3-dione (NBQX) was able to prevent all staining at 5 and 8 DIV and most of the staining at 12 DIV, indicating that the non-NMDA ionotropic glutamate receptors are involved in cobalt uptake into the neurons. The AMPA receptor-selective antagonist GYKI 53655 was used...

  15. Human Trafficking in Indonesia: Law Enforcement Problems

    Directory of Open Access Journals (Sweden)

    Nathalina Naibaho

    2011-01-01

    Full Text Available Human trafficking is considered as a crime against humanity. To conduct the due process of law towards cases related with human trafficking, the law enforcement officers cannot work by themselves. They really need assistance from many parties – such as active report from the society – as a valuable information to disclose such cases. Law enforcement conducted towards woman and child trafficking is still ineffective. It is proven by many existing cases, that low number of processed cases before the court and minimum sanction convicted to the perpetrators is clearly evident. Factors which are deemed to have correlation with low attempt of law enforcement towards legal case on this case, among others are: Lack of the Government’s commitment to fight against the crime of human trafficking, in the event that the ineffectiveness in utilization of prevailing laws and regulation; Lack of capacity of professionalism of law enforcement agency (and relevant parties in handling women and child trafficking at the field. This may be caused by lack of knowledge on infringed regulation. For that matter, those law enforcement agency shall be given socialization and an SOP (standardized operational procedure, so that there will be no inconsistency in handling the existing cases.

  16. Glyphosate and AMPA contents in sediments produced by wind erosion of agricultural soils in Argentina

    Science.gov (United States)

    Aparicio, Virginia; Aimar, Silvia; De Gerónimo, Eduardo; Buschiazzo, Daniel; Mendez, Mariano; Costa, José Luis

    2014-05-01

    Wind erosion of soils is an important event in arid and semiarid regions of Argentina. The magnitude of wind erosion occurring under different management practices is relatively well known in this region but less information is available on the quality of the eroded material. Considering that the intensification of agriculture may increase the concentrations of substances in the eroded material, producing potential negative effects on the environment, we analyzed the amount of glyphosate and AMPA in sediments produced by wind erosion of agricultural soils of Argentina. Wind eroded materials were collected by means of BSNE samplers in two loess sites of the semiarid region of Argentina: Chaco and La Pampa. Samples were collected from 1 ha square fields at 13.5, 50 and 150 cm height. Results showed that at higher heights the concentrations of glyphosate and AMPA were mostly higher. The glyphosate concentration was more variable and higher in Chaco (0.66 to 313 µg kg-1) than in La Pampa (4.17 to 114 µg kg-1). These results may be due to the higher use of herbicides in Chaco, where the predominant crops are soybeans and corn, produced under no-tillage. Under these conditions the use of glyphosate for weeds control is a common practice. Conversely, AMPA concentrations were higher in La Pampa (13.1 to 101.3 µg kg-1) than in Chaco (1.3 to 83 µg kg-1). These preliminary results show high concentrations of glyphosate and AMPA in wind eroded materials of agricultural soils of Argentina. More research is needed to confirm these high concentrations in other conditions in order to detect the temporal and spatial distribution patterns of the herbicide.

  17. Recognizing the trafficking in human beings victimization

    Directory of Open Access Journals (Sweden)

    Simeunović-Patić Biljana

    2008-01-01

    Full Text Available In spite of relative prevalence of trafficking in human beings issues in the expert and general public discourse in recent years, recognition of victimization by various specialists that may come across with victims still is being estimated as unsatisfactory. Stereotypes about victims of trafficking in human beings are just one factor that imperils correct and prompt recognition of victims, i.e. victims' identification, as principal prerequisite of their protection and support. Today, there are various efforts to overcome that problem - primarily through the training of professionals and creating the identification guidelines, i.e. lists of indicators of trafficking in human beings victimization; however, these resolves only one part of the problem and reveal some new challenges at the same time.

  18. Trafficking vesicles: pro or contra pathogens?

    Science.gov (United States)

    Frei dit Frey, Nicolas; Robatzek, Silke

    2009-08-01

    Membrane compartmentalization and trafficking are pivotal for eukaryotic life and demand a higher order of coordination. Even in their resting state, most plant cells exhibit a polarized localization of membrane compartments, which is redirected when plant cells are attacked by microbes. Repositioning of organelles at pathogen penetration sites has been reported since more than a decade; however, only recently has targeted vesicle trafficking upon biotic stress emerged. It has become evident that vesicle secretion and endocytic pathways are engaged in the plant's immune system to actively defend against potential pathogens. By contrast, invasive pathogens have evolved means to utilize these trafficking pathways for the suppression of plant defenses and to the benefit of microbial proliferation. This review summarizes recent findings of host intracellular endomembrane adaptations in response to pathogens and how pathogens exploit them. PMID:19608452

  19. Public Perceptions of Human Trafficking in Moldova

    Directory of Open Access Journals (Sweden)

    Jill Robinson

    2011-11-01

    Full Text Available Human trafficking is a widely studied phenomenon. Comparing public perceptions of trafficking to institutional (i.e. the academy, governmental and non-governmental organizations perceptions gives a richer understanding of the problem. The data for this study were collected in and around Chisinau, Moldova in the summer of 2004. Public discourse provides a more intimate "portraiture" of the issue, but the public also demonstrated a complex level of understanding of this social problem in this study. Its view is juxtaposed against an institutional view of human trafficking as explored through a literature review. Combining institutional and public perceptions and knowledge of a social problem is helpful in not only establishing a more thorough understanding of the social problem and guiding policy decisions, but in exploring the experiences victims may face at the community level.

  20. Chloride in vesicular trafficking and function.

    Science.gov (United States)

    Stauber, Tobias; Jentsch, Thomas J

    2013-01-01

    Luminal acidification is of pivotal importance for the physiology of the secretory and endocytic pathways and its diverse trafficking events. Acidification by the proton-pumping V-ATPase requires charge compensation by counterion currents that are commonly attributed to chloride. The molecular identification of intracellular chloride transporters and the improvement of methodologies for measuring intraorganellar pH and chloride have facilitated the investigation of the physiology of vesicular chloride transport. New data question the requirement of chloride for pH regulation of various organelles and furthermore ascribe functions to chloride that are beyond merely electrically shunting the proton pump. This review surveys the currently established and proposed intracellular chloride transporters and gives an overview of membrane-trafficking steps that are affected by the perturbation of chloride transport. Finally, potential mechanisms of membrane-trafficking modulation by chloride are discussed and put into the context of organellar ion homeostasis in general. PMID:23092411

  1. The adhesion modulation protein, AmpA localizes to an endocytic compartment and influences substrate adhesion, actin polymerization and endocytosis in vegetative Dictyostelium cells

    Directory of Open Access Journals (Sweden)

    Noratel Elizabeth F

    2012-11-01

    Full Text Available Abstract Background AmpA is a secreted 24Kd protein that has pleiotropic effects on Dictyostelium development. Null mutants delay development at the mound stage with cells adhering too tightly to the substrate. Prestalk cells initially specify as prespore cells and are delayed in their migration to the mound apex. Extracellular AmpA can rescue these defects, but AmpA is also necessary in a cell autonomous manner for anterior like cells (ALCs to migrate to the upper cup. The ALCs are only 10% of the developing cell population making it difficult to study the cell autonomous effect of AmpA on the migration of these cells. AmpA is also expressed in growing cells, but, while it contains a hydrophobic leader sequence that is cleaved, it is not secreted from growing cells. This makes growing cells an attractive system for studying the cell autonomous function of AmpA. Results In growing cells AmpA plays an environment dependent role in cell migration. Excess AmpA facilitates migration on soft, adhesive surfaces but hinders migration on less adhesive surfaces. AmpA also effects the level of actin polymerization. Knockout cells polymerize less actin while over expressing cells polymerize more actin than wild type. Overexpression of AmpA also causes an increase in endocytosis that is traced to repeated formation of multiple endocytic cups at the same site on the membrane. Immunofluorescence analysis shows that AmpA is found in the Golgi and colocalizes with calnexin and the slow endosomal recycling compartment marker, p25, in a perinuclear compartment. AmpA is found on the cell periphery and is endocytically recycled to the perinuclear compartment. Conclusion AmpA is processed through the secretory pathway and traffics to the cell periphery where it is endocytosed and localizes to what has been defined as a slow endosomal recycling compartment. AmpA plays a role in actin polymerization and cell substrate adhesion. Additionally AmpA influences cell

  2. Quantifying the effects of co-expressing EGFR and HER2 on HER activation and trafficking

    Energy Technology Data Exchange (ETDEWEB)

    Shankaran, Harish; Zhang, Yi; Opresko, Lee; Resat, Haluk

    2008-06-27

    The integration of experimental measurements and computational predictions is a powerful means to understand the molecular mechanisms of complex biological systems. The human epidermal growth factor receptor (HER) system is an intricately regulated system that plays critical roles in development and tumorigenesis. Here, we apply integrated experimentation and modeling to analyze HER receptor activation in a panel of cell lines expressing different levels of HER1 and HER2. A mathematical model that includes the fundamental biochemical/biophysical processes involved in receptor activation was used to fit the experimental data, and 19 independent parameters including receptor dimerization affinities, trafficking rates and relative phosphorylation levels were estimated. The parameter values quantitatively support existing ideas on the effect of HER2 on HER1 phosphorylation dynamics, and enable us to predict receptor dimerization patterns in the cell lines. The integrated approach described here can be applied to obtain a predictive understanding of other biomolecular systems.

  3. THE TRAFFICKING OF MOLDOVAN MINORS IN ITALY

    Directory of Open Access Journals (Sweden)

    Maria Cristina GIANNINI

    2011-12-01

    Full Text Available The research analyzes the phenomenon of trafficking of moldavan minors for sexual exploitation in Italy and in the European context trying to measure the quantitative and qualitative incidencef the criminal problem. Through a questionnaire submitted to the responsibles of the Italian centers of assistance (according Italian legislation recovering moldovian minors for the period 2000 – 2008, it has been possible to evaluate all the variables concerning the victims and the traffickers and to reach specific conclusions regarding the adoption of preventive measures in the short and long term. The study suggests the integration of two convergent approaches in a transnational dynamic perspective.

  4. Human Trafficking as Lever for Feminist Voices?

    DEFF Research Database (Denmark)

    Spanger, Marlene

    2011-01-01

    In Denmark, human trafficking has emerged as a central issue within the policy field of prostitution during the last decade. Taking a Foucauldian approach from a historical perspective, understanding the policy field of prostitution as a discursive terrain, the article analyses the thinking...... that lies behind policies on prostitution by identifying ruptures and discursive struggles which lead to transformations of the policy field. In particular, this article investigates how the problematisation of human trafficking has created space for a feminist discourse breakthrough within the policy field...

  5. Human telomerase: biogenesis, trafficking, recruitment, and activation.

    Science.gov (United States)

    Schmidt, Jens C; Cech, Thomas R

    2015-06-01

    Telomerase is the ribonucleoprotein enzyme that catalyzes the extension of telomeric DNA in eukaryotes. Recent work has begun to reveal key aspects of the assembly of the human telomerase complex, its intracellular trafficking involving Cajal bodies, and its recruitment to telomeres. Once telomerase has been recruited to the telomere, it appears to undergo a separate activation step, which may include an increase in its repeat addition processivity. This review covers human telomerase biogenesis, trafficking, and activation, comparing key aspects with the analogous events in other species.

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

    OpenAIRE

    Knafo, Shira; Sánchez-Puelles, Cristina; Franco, A; Esteban, José A.

    2012-01-01

    Cell adhesion molecules and downstream growth factor-dependent signaling are critical for brain development and synaptic plasticity, and they have been linked to cognitive function in adult animals. We have previously developed a mimetic peptide (FGL) from the neural cell adhesion molecule (NCAM) 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...

  7. Role of the Ventral Tegmental Area in Methamphetamine Extinction: AMPA Receptor-Mediated Neuroplasticity

    Science.gov (United States)

    Chen Han-Ting; Chen, Jin-Chung

    2015-01-01

    The molecular mechanisms underlying drug extinction remain largely unknown, although a role for medial prefrontal cortex (mPFC) glutamate neurons has been suggested. Considering that the mPFC sends glutamate efferents to the ventral tegmental area (VTA), we tested whether the VTA is involved in methamphetamine (METH) extinction via conditioned…

  8. 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 resti

  9. 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...... swim (FST) and tail suspension tests (TST), and anxiety-related behaviour using the elevated zero maze (EZM), marble burying (MB) and novelty-induced hypophagia (NIH) tests. The serotonin-selective antidepressant citalopram was included for comparison. Due to the importance of AMPARs in learning......-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...

  10. 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

    Cell adhesion molecules and downstream growth factor-dependent signaling are critical for brain development and synaptic plasticity, and they have been linked to cognitive function in adult animals. We have previously developed a mimetic peptide (FGL) from the neural cell adhesion molecule (NCAM)...

  11. 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).…

  12. Pathologies of Security Governance: Efforts Against Human Trafficking in Europe

    OpenAIRE

    Friesendorf, Cornelius

    2007-01-01

    The trafficking of women and girls for the purpose of sexual exploitation has reportedly been booming in Europe since the 1990s. Governments, international organizations, and private actors have addressed the causes and consequences of sex trafficking in various ways. This article shows that the concept of security governance helps to understand efforts against human trafficking and their shortcomings. The anti-trafficking security governance system consists of five approaches: legal measure...

  13. Human trafficking: fighting the illicit economy with the legitimate economy

    OpenAIRE

    Louise Shelley; Christina Bain

    2015-01-01

    Since the beginning of research on human trafficking, there has been attention paid to the challenges surrounding the illicit economy. In creating new strategies and initiatives on combatting human trafficking, there needs to be more discussion surrounding the legitimate economy and how the business sector can make an impact in the fight against trafficking. Currently, there is a growing movement of businesses that are looking to address human trafficking through training, education, and lead...

  14. Human Trafficking: The Role of the Health Care Provider

    OpenAIRE

    Dovydaitis, Tiffany

    2010-01-01

    Human trafficking is a major public health problem, both domestically and internationally. Health care providers are often the only professionals to interact with trafficking victims who are still in captivity. The expert assessment and interview skills of providers contribute to their readiness to identify victims of trafficking. The purpose of this article is to provide clinicians with knowledge on trafficking and give specific tools that they may use to assist victims in the clinical setti...

  15. Endocytic Trafficking of Membrane-Bound Cargo: A Flotillin Point of View

    Directory of Open Access Journals (Sweden)

    Melanie Meister

    2014-07-01

    Full Text Available The ubiquitous and highly conserved flotillin proteins, flotillin-1 and flotillin-2, have been shown to be involved in various cellular processes such as cell adhesion, signal transduction through receptor tyrosine kinases as well as in cellular trafficking pathways. Due to the fact that flotillins are acylated and form hetero-oligomers, they constitutively associate with cholesterol-enriched lipid microdomains. In recent years, such microdomains have been appreciated as platforms that participate in endocytosis and other cellular trafficking steps. This review summarizes the current findings on the role of flotillins in membrane-bound cargo endocytosis and endosomal trafficking events. We will discuss the proposed function of flotillins in endocytosis in the light of recent findings that point towards a role for flotillins in a step that precedes the actual endocytic uptake of cargo molecules. Recent findings have also revealed that flotillins may be important for endosomal sorting and recycling of specific cargo molecules. In addition to these aspects, the cellular trafficking pathway of flotillins themselves as potential cargo in the context of growth factor signaling will be discussed.

  16. Child organ trafficking: global reality and inadequate international response.

    Science.gov (United States)

    Bagheri, Alireza

    2016-06-01

    In organ transplantation, the demand for human organs has grown far faster than the supply of organs. This has opened the door for illegal organ trade and trafficking including from children. Organized crime groups and individual organ brokers exploit the situation and, as a result, black markets are becoming more numerous and organized organ trafficking is expanding worldwide. While underprivileged and vulnerable men and women in developing countries are a major source of trafficked organs, and may themselves be trafficked for the purpose of illegal organ removal and trade, children are at especial risk of exploitation. With the confirmed cases of children being trafficked for their organs, child organ trafficking, which once called a "modern urban legend", is a sad reality in today's world. By presenting a global picture of child organ trafficking, this paper emphasizes that child organ trafficking is no longer a myth but a reality which has to be addressed. It argues that the international efforts against organ trafficking and trafficking in human beings for organ removal have failed to address child organ trafficking adequately. This chapter suggests that more orchestrated international collaboration as well as development of preventive measure and legally binding documents are needed to fight child organ trafficking and to support its victims. PMID:26612382

  17. Human Trafficking: A Review for Mental Health Professionals

    Science.gov (United States)

    Yakushko, Oksana

    2009-01-01

    This article provides a review of current research on human trafficking for mental health practitioners and scholars. In addition to an overview of definitions, causes and processes of trafficking, the article highlights mental health consequences of trafficking along with suggestions for treatment of survivors. Directions for counseling services,…

  18. Trafficking of Children in Albania: Patterns of Recruitment and Reintegration

    Science.gov (United States)

    Gjermeni, Eglantina; Van Hook, Mary P.; Gjipali, Saemira; Xhillari, Lindita; Lungu, Fatjon; Hazizi, Anila

    2008-01-01

    Problem: Many children in Albania and other countries of Eastern Europe are being trafficked as part of the global business of human trafficking. Objectives: The study sought to identify the patterns of child trafficking involving Albanian children, and especially children's views of the role of family issues and the nature of the trafficking…

  19. Child organ trafficking: global reality and inadequate international response.

    Science.gov (United States)

    Bagheri, Alireza

    2016-06-01

    In organ transplantation, the demand for human organs has grown far faster than the supply of organs. This has opened the door for illegal organ trade and trafficking including from children. Organized crime groups and individual organ brokers exploit the situation and, as a result, black markets are becoming more numerous and organized organ trafficking is expanding worldwide. While underprivileged and vulnerable men and women in developing countries are a major source of trafficked organs, and may themselves be trafficked for the purpose of illegal organ removal and trade, children are at especial risk of exploitation. With the confirmed cases of children being trafficked for their organs, child organ trafficking, which once called a "modern urban legend", is a sad reality in today's world. By presenting a global picture of child organ trafficking, this paper emphasizes that child organ trafficking is no longer a myth but a reality which has to be addressed. It argues that the international efforts against organ trafficking and trafficking in human beings for organ removal have failed to address child organ trafficking adequately. This chapter suggests that more orchestrated international collaboration as well as development of preventive measure and legally binding documents are needed to fight child organ trafficking and to support its victims.

  20. 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.

  1. Cav1.3 L-type Ca2+ channels mediate long-term adaptation in dopamine D2L-mediated GluA1 trafficking in the dorsal striatum following cocaine exposure

    OpenAIRE

    Schierberl, Kathryn; Giordano, Thomas; Satpute, Shirish; HAO, JIN; Kaur, Gagandeep; Hofmann, Franz; Moosmang, Sven; Striessnig, Joerg; Rajadhyaksha, Anjali

    2012-01-01

    AMPA receptor (AMPAR) plasticity at glutamatergic synapses in the mesostriatal dopaminergic pathway has been implicated in persistent cocaine-induced behavioral responses; however, the precise mechanism underlying these changes remains unknown. Utilizing cocaine psychomotor sensitization in mice we find that repeated cocaine results in a basal reduction of Ser 845 GluA1 and cell surface GluA1 levels in the dorsal striatum (dStr) following a protracted withdrawal period, an adaptation that is ...

  2. South Africa - safe haven for human traffickers? Employing the arsenal of existing law to combat human trafficking

    OpenAIRE

    H. Oosthuizen; HB Kruger

    2012-01-01

    aving ratified the Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children, South Africa is obliged to adopt legislative measures that criminalise human trafficking and comply with other standards laid down in this international instrument. However, by mid-2011, South Africa had not enacted the required comprehensive counter-trafficking legislation. The question that now arises is if the absence of such anti-trafficking legislation poses an insurmountabl...

  3. Separating the Innocents from the Illegals: visual representation of the victims of sex trafficking in anti-trafficking campaigns

    OpenAIRE

    Stolic, Tijana

    2014-01-01

    This thesis critically explores the discursive formations around the visual representation of the victims of sex trafficking in six anti-trafficking campaigns totalling 18 photographs. Critical discourse analysis is utilised as a methodological approach, while semiotics and iconography are used as methods of visual analysis. Picking up on the previous studies of the discourses of trafficking, the study aims to place the dominant discourses of trafficking into the context of humanitarian appea...

  4. Sources and Input Pathways of Glyphosate and its Degradation Product AMPA

    Science.gov (United States)

    Bischofberger, S.; Hanke, I.; Wittmer, I.; Singer, H.; Stamm, C.

    2009-04-01

    Despite being the pesticide used in the largest quantities worldwide, the environmental relevance of glyphosate has been considered low for many years. Reasons for this assessment were the observations that glyphosate degrades quickly into its degradation product AMPA and that it sorbs strongly to soil particles. Hence, little losses to water bodies had been expected. Research during the last few years however contradicts this expectation. Although glyphosate is a dominant pesticide used in agriculture, recent studies on other pesticides revealed that urban sources may play a significant role for water quality. Therefore this study compares glyphosate input into streams from agricultural and urban sources. For that purpose, a catchment of an area of 25 km2 was selected. It has by about 12'000 inhabitants and about 15 % of the area is used as arable land. Four sampling sites were selected in the river system in order to reflect different urban and agricultural sources. Additionally, we sampled a combined sewer overflow, a rain sewer and the outflow of a waste water treatment plant. At each site discharge was measured continuously from March to November 2007. During 16 rain events samples were taken by automatic devices at a high temporal resolution. To analyze the concentration of glyphosate and its degradation product AMPA, the samples were derivatized with FMOC-Cl at low pH conditions and then filtrated. The solid phase extraction was conducted with Strata-X sorbent cartridge. Glyphosate and AMPA were detected with API 4000 after the chromatography with X bridge column C18. To assure the data quality, interne standards of Glyphosate and AMPA were added to every sample. The limit of detection and quantification for glyphosate and AMPA are bellow 1ng/l. We analyzed two rain events at a high resolution for all stations and several events at the outlet of the catchment. We measured high glyphosate concentration in urban and agriculture dominated catchments with up to

  5. Global recycling - waste trafficking in disguise?

    DEFF Research Database (Denmark)

    Kamuk, Bettina; Hansen, Jens Aage

    2007-01-01

    Recycling is used as cover for illegal exporting of hazardous wastes (waste trafficking). This happens in spite of international conventions and codes of good conduct. Additional rules and recommendations are suggested to initiatiate local and national action and compliance with international...

  6. Reflections on initiatives to address human trafficking

    Directory of Open Access Journals (Sweden)

    Bandana Pattanaik

    2006-05-01

    Full Text Available Many organisations, politicians and celebrities have joined the fight against human trafficking but have they stopped to consider the causes of the phenomenon and the human rights of those affected by it and/or by ill-judged actions to suppress it?

  7. Psychological characteristics of victims of trafficking

    Directory of Open Access Journals (Sweden)

    Larin A.N.

    2015-11-01

    Full Text Available The article describes the main causes of falling into slavery, forms of slave labour, as well as moral-psychological properties and characteristics of potential victims of trafficking. Noted risk factors leading to victimization of the person and increase the possibility of becoming an object for criminal groups specializing in this kind of crime. The number of victims of international trafficking ranges from 600 to 800 thousand people a year, and when you consider human trafficking within the individual countries, the total number of victims ranges from 2 to 4 million people. 80% of trafficked people are women and children, of which 70% are sold to other countries for sexual exploitation. According to the International organization for migration (International Organization of Migration annually only in the European markets of prostitution sold is not less than 500 thousand women. Among the personal factors that affect the increase in the number of such crimes, it is necessary to indicate family trouble, which manifests itself, primarily, to neglect, loss of relationships with family and parents, or in the absence of moral and material support from existing family and friends.

  8. LEGAL FRAMEWORKS ON TRAFFICKING IN PERSONS

    Directory of Open Access Journals (Sweden)

    Fabio PAOLINI

    2012-11-01

    Full Text Available Always in order to realize the best prevention and contrast of the trafficking of minors, the research underlines the necessity of armonization all the national legislations (up to now well 27 differet approaches pertaining to each EU member states according the numerous directives formulated and reproposed by the European authorities.

  9. Neuronal trafficking: basic mechanisms and ALS pathology

    NARCIS (Netherlands)

    Kuijpers, M.

    2014-01-01

    A cell is divided into different compartments and organelles, which enables the cell to create specialized environments for specific functions. To perform these functions, organelles need a unique composition of proteins and lipids. By actively controlling the trafficking of proteins and membrane li

  10. Human Trafficking, Globalisation and Transnational Feminist Responses

    NARCIS (Netherlands)

    T-D. Truong (Thanh-Dam)

    2014-01-01

    textabstractThis paper presents a historical overview of feminist frameworks for analysis and advocacy on human trafficking. It traces the major differences and similarities in the forms of knowledge produced since the Anti-White Slavery campaigns nearly two centuries ago. It highlights how institut

  11. Sinai Trafficking: Origin and Definition of a New Form of Human Trafficking

    Directory of Open Access Journals (Sweden)

    Mirjam van Reisen

    2015-02-01

    Full Text Available The phenomenon that is coined “Sinai Trafficking” started in 2009 in the Sinai desert. It involves the abduction, extortion, sale, torture, sexual violation and killing of men, women and children. Migrants, of whom the vast majority are from Eritrean descent, are abducted and brought to the Sinai desert, where they are sold and resold, extorted for very high ransoms collected by mobile phone, while being brutally and “functionally” tortured to support the extortion. Many of them die in Sinai. Over the last five years broadcasting stations, human rights organisations and academics have reported on the practices in the Sinai and some of these reports have resulted in some confusion on the modus operandi. Based on empirical research by the authors and the analysis of data gathered in more than 200 recorded interviews with Sinai hostages and survivors on the practices, this article provides a definition of Sinai Trafficking. It argues that the term Sinai Trafficking can be used to differentiate a particular new set of criminal practices that have first been reported in the Sinai Peninsula. The article further examines how the new phenomenon of Sinai Trafficking can be framed into the legal human trafficking definition. The interconnectedness of Sinai Trafficking with slavery, torture, ransom collection, extortion, sexual violence and other severe crimes is presented to substantiate the use of the trafficking framework. The plight of Sinai survivors in Israel and Egypt is explained to illustrate the cyclical process of the trafficking practices especially endured by Eritreans, introduced as the Human Trafficking Cycle. The article concludes by setting out areas for further research.

  12. Child trafficking in Tanzania: Experiences of Trafficked Girls in Dar es Salaam

    OpenAIRE

    Kavishe, Angela

    2011-01-01

    This study focuses on the experiences of trafficked children in Tanzania. Trafficking of children deprives them of human rights and freedoms; it may also pose a public health risk. Migration of children who are fostered by extended family is a long-standing customary practice in Tanzania, but while the circumstances of fostering have changed, given increasing rural poverty and the impact of the HIV/AIDS, this has not been recognized in Tanzanian society. The government enacted the Anti-Traffi...

  13. Heterogeneous intracellular trafficking dynamics of brain-derived neurotrophic factor complexes in the neuronal soma revealed by single quantum dot tracking.

    Directory of Open Access Journals (Sweden)

    Anke Vermehren-Schmaedick

    Full Text Available Accumulating evidence underscores the importance of ligand-receptor dynamics in shaping cellular signaling. In the nervous system, growth factor-activated Trk receptor trafficking serves to convey biochemical signaling that underlies fundamental neural functions. Focus has been placed on axonal trafficking but little is known about growth factor-activated Trk dynamics in the neuronal soma, particularly at the molecular scale, due in large part to technical hurdles in observing individual growth factor-Trk complexes for long periods of time inside live cells. Quantum dots (QDs are intensely fluorescent nanoparticles that have been used to study the dynamics of ligand-receptor complexes at the plasma membrane but the value of QDs for investigating ligand-receptor intracellular dynamics has not been well exploited. The current study establishes that QD conjugated brain-derived neurotrophic factor (QD-BDNF binds to TrkB receptors with high specificity, activates TrkB downstream signaling, and allows single QD tracking capability for long recording durations deep within the soma of live neurons. QD-BDNF complexes undergo internalization, recycling, and intracellular trafficking in the neuronal soma. These trafficking events exhibit little time-synchrony and diverse heterogeneity in underlying dynamics that include phases of sustained rapid motor transport without pause as well as immobility of surprisingly long-lasting duration (several minutes. Moreover, the trajectories formed by dynamic individual BDNF complexes show no apparent end destination; BDNF complexes can be found meandering over long distances of several microns throughout the expanse of the neuronal soma in a circuitous fashion. The complex, heterogeneous nature of neuronal soma trafficking dynamics contrasts the reported linear nature of axonal transport data and calls for models that surpass our generally limited notions of nuclear-directed transport in the soma. QD-ligand probes are

  14. Domestic minor sex trafficking: what the PNP needs to know.

    Science.gov (United States)

    Hornor, Gail

    2015-01-01

    Human trafficking is a major global public health problem and represents a substantial human rights violation. Human trafficking has been receiving attention in both the lay media and professional literature. Human trafficking can include commercial sex, forced labor, child soldiers, and stealing of human organs. One form of human trafficking represents a significant American pediatric health problem: domestic minor sex trafficking (DMST). DMST is the commercial sexual abuse of children by selling, buying, or trading their sexual service. This continuing education article will define DMST and discuss it in terms of prevalence, risk factors, and practice implications for the pediatric nurse practitioner. PMID:25497135

  15. Domestic minor sex trafficking: what the PNP needs to know.

    Science.gov (United States)

    Hornor, Gail

    2015-01-01

    Human trafficking is a major global public health problem and represents a substantial human rights violation. Human trafficking has been receiving attention in both the lay media and professional literature. Human trafficking can include commercial sex, forced labor, child soldiers, and stealing of human organs. One form of human trafficking represents a significant American pediatric health problem: domestic minor sex trafficking (DMST). DMST is the commercial sexual abuse of children by selling, buying, or trading their sexual service. This continuing education article will define DMST and discuss it in terms of prevalence, risk factors, and practice implications for the pediatric nurse practitioner.

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

    International Nuclear Information System (INIS)

    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

  17. Kainate receptors mediate signaling in both transient and sustained OFF bipolar cell pathways in mouse retina.

    Science.gov (United States)

    Borghuis, Bart G; Looger, Loren L; Tomita, Susumu; Demb, Jonathan B

    2014-04-30

    A fundamental question in sensory neuroscience is how parallel processing is implemented at the level of molecular and circuit mechanisms. In the retina, it has been proposed that distinct OFF cone bipolar cell types generate fast/transient and slow/sustained pathways by the differential expression of AMPA- and kainate-type glutamate receptors, respectively. However, the functional significance of these receptors in the intact circuit during light stimulation remains unclear. Here, we measured glutamate release from mouse bipolar cells by two-photon imaging of a glutamate sensor (iGluSnFR) expressed on postsynaptic amacrine and ganglion cell dendrites. In both transient and sustained OFF layers, cone-driven glutamate release from bipolar cells was blocked by antagonists to kainate receptors but not AMPA receptors. Electrophysiological recordings from bipolar and ganglion cells confirmed the essential role of kainate receptors for signaling in both transient and sustained OFF pathways. Kainate receptors mediated responses to contrast modulation up to 20 Hz. Light-evoked responses in all mouse OFF bipolar pathways depend on kainate, not AMPA, receptors.

  18. Drug Trafficking into Macrophages via the Endocytotic Receptor CD163

    OpenAIRE

    Jonas Heilskov Graversen; Søren Kragh Moestrup

    2015-01-01

    In inflammatory diseases, macrophages are a main producer of a range of cytokines regulating the inflammatory state. This also includes inflammation induced by tumor growth, which recruits so-called tumor-associated macrophages supporting tumor growth. Macrophages are therefore relevant targets for cytotoxic or phenotype-modulating drugs in the treatment of inflammatory and cancerous diseases. Such targeting of macrophages has been tried using the natural propensity of macrophages to non-spe...

  19. Drug Trafficking into Macrophages via the Endocytotic Receptor CD163

    DEFF Research Database (Denmark)

    Graversen, Jonas Heilskov; Moestrup, Søren Kragh

    2015-01-01

    for cytotoxic or phenotype-modulating drugs in the treatment of inflammatory and cancerous diseases. Such targeting of macrophages has been tried using the natural propensity of macrophages to non-specifically phagocytose circulating foreign particulate material. In addition, the specific targeting...

  20. Multilayered proteomics reveals molecular switches dictating ligand-dependent EGFR trafficking

    DEFF Research Database (Denmark)

    Francavilla, Chiara; Papetti, Moreno; Rigbolt, Kristoffer T G;

    2016-01-01

    A fascinating conundrum in cell signaling is how stimulation of the same receptor tyrosine kinase with distinct ligands generates specific outcomes. To decipher the functional selectivity of EGF and TGF-α, which induce epidermal growth factor receptor (EGFR) degradation and recycling, respectively...... identified RAB7 phosphorylation and RCP recruitment to EGFR as switches for EGF and TGF-α outputs, controlling receptor trafficking, signaling duration, proliferation, and migration. By manipulating RCP levels or phosphorylation of RAB7 in EGFR-positive cancer cells, we were able to switch a TGF......, we devised an integrated multilayered proteomics approach (IMPA). We analyzed dynamic changes in the receptor interactome, ubiquitinome, phosphoproteome, and late proteome in response to both ligands in human cells by quantitative MS and identified 67 proteins regulated at multiple levels. We...

  1. Abrin immunotoxin: targeted cytotoxicity and intracellular trafficking pathway.

    Directory of Open Access Journals (Sweden)

    Sudarshan Gadadhar

    Full Text Available BACKGROUND: Immunotherapy is fast emerging as one of the leading modes of treatment of cancer, in combination with chemotherapy and radiation. Use of immunotoxins, proteins bearing a cell-surface receptor-specific antibody conjugated to a toxin, enhances the efficacy of cancer treatment. The toxin Abrin, isolated from the Abrus precatorius plant, is a type II ribosome inactivating protein, has a catalytic efficiency higher than any other toxin belonging to this class of proteins but has not been exploited much for use in targeted therapy. METHODS: Protein synthesis assay using (3[H] L-leucine incorporation; construction and purification of immunotoxin; study of cell death using flow cytometry; confocal scanning microscopy and sub-cellular fractionation with immunoblot analysis of localization of proteins. RESULTS: We used the recombinant A chain of abrin to conjugate to antibodies raised against the human gonadotropin releasing hormone receptor. The conjugate inhibited protein synthesis and also induced cell death specifically in cells expressing the receptor. The conjugate exhibited differences in the kinetics of inhibition of protein synthesis, in comparison to abrin, and this was attributed to differences in internalization and trafficking of the conjugate within the cells. Moreover, observations of sequestration of the A chain into the nucleus of cells treated with abrin but not in cells treated with the conjugate reveal a novel pathway for the movement of the conjugate in the cells. CONCLUSIONS: This is one of the first reports on nuclear localization of abrin, a type II RIP. The immunotoxin mAb F1G4-rABRa-A, generated in our laboratory, inhibits protein synthesis specifically on cells expressing the gonadotropin releasing hormone receptor and the pathway of internalization of the protein is distinct from that seen for abrin.

  2. Important relationships between Rab and MICAL proteins in endocytic trafficking

    Institute of Scientific and Technical Information of China (English)

    Juliati; Rahajeng; Sai; Srinivas; Panapakkam; Giridharan; Naava; Naslavsky; Steve; Caplan

    2010-01-01

    The internalization of essential nutrients,lipids and receptors is a crucial process for all eukaryotic cells.Accordingly,endocytosis is highly conserved across cell types and species.Once internalized,small cargocontaining vesicles fuse with early endosomes(also known as sorting endosomes),where they undergo segregation to distinct membrane regions and are sorted and transported on through the endocytic pathway.Although the mechanisms that regulate this sorting are still poorly understood,some receptors are directed to late endosomes and lysosomes for degradation,whereas other receptors are recycled back to the plasma membrane;either directly or through recycling endosomes.The Rab family of small GTP-binding proteins plays crucial roles in regulating these trafficking pathways.Rabs cycle from inactive GDP-bound cytoplasmic proteins to active GTP-bound membraneassociated proteins,as a consequence of the activity of multiple specific GTPase-activating proteins(GAPs) and GTP exchange factors(GEFs).Once bound to GTP,Rabs interact with a multitude of effector proteins that carry out Rab-specific functions.Recent studies have shown that some of these effectors are also interaction partners for the C-terminal Eps15 homology(EHD) proteins,which are also intimately involved in endocytic regulation.A particularly interesting example of common Rab-EHD interaction partners is the MICALlike protein,MICAL-L1.MICAL-L1 and its homolog,MICAL-L2,belong to the larger MICAL family of proteins,and both have been directly implicated in regulating endocytic recycling of cell surface receptors and junctional proteins,as well as controlling cytoskeletal rearrangement and neurite outgrowth.In this review,we summarize the functional roles of MICAL and Rab proteins,and focus on the significance of their interactions and the implications for endocytic transport.

  3. South Africa – Safe Haven for Human Traffickers? Employing the Arsenal of Existing Law to Combat Human Trafficking

    Directory of Open Access Journals (Sweden)

    H Oosthuizen

    2012-03-01

    Full Text Available aving ratified the Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children, South Africa is obliged to adopt legislative measures that criminalise human trafficking and comply with other standards laid down in this international instrument. However, by mid-2011, South Africa had not enacted the required comprehensive counter-trafficking legislation. The question that now arises is if the absence of such anti-trafficking legislation poses an insurmountable obstacle to the prosecution of traffickers for trafficking-related activities. In asking this question the article examines the utilisation of existing crimes in order to prosecute and punish criminal activities committed during the human trafficking process. Firstly, a selection of existing common law and statutory crimes that may often be applicable to trafficking related activities is mapped out. Secondly, transitional trafficking provisions in the Children's Act 38 of 2005 and the Criminal Law (Sexual Offences and Related Matters Amendment Act 32 of 2007 are discussed. Finally, since the Prevention and Combating of Trafficking in Persons Bill B7 of 2010 will in all probability be enacted in the near future, the use of other criminal law provisions in human trafficking prosecutions, even after the passing of this bill into law, is reflected upon.

  4. Excess sphingomyelin disturbs ATG9A trafficking and autophagosome closure.

    Science.gov (United States)

    Corcelle-Termeau, Elisabeth; Vindeløv, Signe Diness; Hämälistö, Saara; Mograbi, Baharia; Keldsbo, Anne; Bräsen, Jan Hinrich; Favaro, Elena; Adam, Dieter; Szyniarowski, Piotr; Hofman, Paul; Krautwald, Stefan; Farkas, Thomas; Petersen, Nikolaj H T; Rohde, Mikkel; Linkermann, Andreas; Jäättelä, Marja

    2016-05-01

    Sphingomyelin is an essential cellular lipid that traffics between plasma membrane and intracellular organelles until directed to lysosomes for SMPD1 (sphingomyelin phosphodiesterase 1)-mediated degradation. Inactivating mutations in the SMPD1 gene result in Niemann-Pick diseases type A and B characterized by sphingomyelin accumulation and severely disturbed tissue homeostasis. Here, we report that sphingomyelin overload disturbs the maturation and closure of autophagic membranes. Niemann-Pick type A patient fibroblasts and SMPD1-depleted cancer cells accumulate elongated and unclosed autophagic membranes as well as abnormally swollen autophagosomes in the absence of normal autophagosomes and autolysosomes. The immature autophagic membranes are rich in WIPI2, ATG16L1 and MAP1LC3B but display reduced association with ATG9A. Contrary to its normal trafficking between plasma membrane, intracellular organelles and autophagic membranes, ATG9A concentrates in transferrin receptor-positive juxtanuclear recycling endosomes in SMPD1-deficient cells. Supporting a causative role for ATG9A mistrafficking in the autophagy defect observed in SMPD1-deficient cells, ectopic ATG9A effectively reverts this phenotype. Exogenous C12-sphingomyelin induces a similar juxtanuclear accumulation of ATG9A and subsequent defect in the maturation of autophagic membranes in healthy cells while the main sphingomyelin metabolite, ceramide, fails to revert the autophagy defective phenotype in SMPD1-deficient cells. Juxtanuclear accumulation of ATG9A and defective autophagy are also evident in tissues of smpd1-deficient mice with a subsequent inability to cope with kidney ischemia-reperfusion stress. These data reveal sphingomyelin as an important regulator of ATG9A trafficking and maturation of early autophagic membranes. PMID:27070082

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

    Science.gov (United States)

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

    2015-09-01

    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.

  6. GABAB receptors modulate NMDA receptor calcium signals in dendritic spines.

    Science.gov (United States)

    Chalifoux, Jason R; Carter, Adam G

    2010-04-15

    Metabotropic GABA(B) receptors play a fundamental role in modulating the excitability of neurons and circuits throughout the brain. These receptors influence synaptic transmission by inhibiting presynaptic release or activating postsynaptic potassium channels. However, their ability to directly influence different types of postsynaptic glutamate receptors remains unresolved. Here we examine GABA(B) receptor modulation in layer 2/3 pyramidal neurons from the mouse prefrontal cortex. We use two-photon laser-scanning microscopy to study synaptic modulation at individual dendritic spines. Using two-photon optical quantal analysis, we first demonstrate robust presynaptic modulation of multivesicular release at single synapses. Using two-photon glutamate uncaging, we then reveal that GABA(B) receptors strongly inhibit NMDA receptor calcium signals. This postsynaptic modulation occurs via the PKA pathway and does not affect synaptic currents mediated by AMPA or NMDA receptors. This form of GABA(B) receptor modulation has widespread implications for the control of calcium-dependent neuronal function.

  7. Plasma membrane protein trafficking in plant-microbe interactions: a plant cell point of view

    Directory of Open Access Journals (Sweden)

    Nathalie eLeborgne-Castel

    2014-12-01

    Full Text Available In order to ensure their physiological and cellular functions, plasma membrane (PM proteins must be properly conveyed from their site of synthesis, i.e. the endoplasmic reticulum, to their final destination, the PM, through the secretory pathway. PM protein homeostasis also relies on recycling and/or degradation, two processes that are initiated by endocytosis. Vesicular membrane trafficking events to and from the PM have been shown to be altered when plant cells are exposed to mutualistic or pathogenic microbes. In this review, we will describe the fine-tune regulation of such alterations, and their consequence in PM protein activity. We will consider the formation of intracellular perimicrobial compartments, the PM protein trafficking machinery of the host, and the delivery or retrieval of signaling and transport proteins such as pattern-recognition receptors, producers of reactive oxygen species, and sugar transporters.

  8. Depth distribution of glyphosate and AMPA under diferent tillage system and soils in long-term experiments

    Science.gov (United States)

    Aparicio, Virginia; Costa, Jose Luis; De Geronimo, Eduardo

    2016-04-01

    Glyphosate (N-(phosphonomethyl glycine) is a post-emergence, non-selective, foliar herbicide. Around 200 million liters of this herbicide are applied every year in Argentina, where the main agricultural practice is no-till (NT), accounting for 78 % of the cultivated land. In this work, we studied the depth distribution of glyphosate in long-term experiments (more than 15 years) at different locations under NT and conventional tillage (CT). Samples from 0-2, 2-5, 5-10, 10-15, and 15-20 cm depth with four replication and two treatments NT CT at three locations: Balcarce (BA) a loam soil, Bordenave (BO) a sandy loam soil y Marcos Juarez a silty loam soil (MJ). The glyphosate concentration in the first 2 cm of soil was, on the average, 70% greater than in the next 2-5 cm. The mass of glyphosate in CT was higher at 2 to 10 cm depth. The depth concentration of AMPA follows the same trend than glyphosate, although its average concentration at 0-2 cm depth is 28 times higher than the glyphosate concentration at 2-5 cm (glyphosate = 147 ppb and AMPA = 4100 ppb). Beside the AMPA concentration at 0-2 cm depth is greater in NT than in CT, the mass of AMPA is higher in CT only for the Balcarce location. To our knowledge, this study is the first dealing with the depth distribution of glyphosate concentration in soils under different soil managements. In the present study, it was demonstrated that glyphosate and AMPA are present in soils under agricultural activity with maximum concentration in the first two cm of soil and the AMPA concentration at this depth is greater in NT than in CT.

  9. PI3K-C2α: One enzyme for two products coupling vesicle trafficking and signal transduction.

    Science.gov (United States)

    Campa, Carlo C; Franco, Irene; Hirsch, Emilio

    2015-06-22

    The spatial restriction of phosphorylated phosphoinositides generated downstream activated membrane receptors is critical for proper cell response to environmental cues. The α isoform of class II PI3Ks, PI3K-C2α, has emerged as a modulator of receptor localization, acting both in the control of receptor endocytosis and resensitization. This unexpectedly versatile enzyme was found to differentially produce two distinct 3-phosphorylated phosphoinositides and to selectively control distinct steps of vesicular traffic such as endocytosis and recycling. This review focuses on the latest discoveries regarding PI3K-C2α function in vesicle trafficking and its impact on cell biology and mammalian embryonic development.

  10. Incunabular immunological events in prion trafficking.

    Science.gov (United States)

    Michel, Brady; Meyerett-Reid, Crystal; Johnson, Theodore; Ferguson, Adam; Wyckoff, Christy; Pulford, Bruce; Bender, Heather; Avery, Anne; Telling, Glenn; Dow, Steven; Zabel, Mark D

    2012-01-01

    While prions probably interact with the innate immune system immediately following infection, little is known about this initial confrontation. Here we investigated incunabular events in lymphotropic and intranodal prion trafficking by following highly enriched, fluorescent prions from infection sites to draining lymph nodes. We detected biphasic lymphotropic transport of prions from the initial entry site upon peripheral prion inoculation. Prions arrived in draining lymph nodes cell autonomously within two hours of intraperitoneal administration. Monocytes and dendritic cells (DCs) required Complement for optimal prion delivery to lymph nodes hours later in a second wave of prion trafficking. B cells constituted the majority of prion-bearing cells in the mediastinal lymph node by six hours, indicating intranodal prion reception from resident DCs or subcapsulary sinus macrophages or directly from follicular conduits. These data reveal novel, cell autonomous prion lymphotropism, and a prominent role for B cells in intranodal prion movement. PMID:22679554

  11. Sex Trafficking: Policies, Programs, and Services.

    Science.gov (United States)

    Orme, Julie; Ross-Sheriff, Fariyal

    2015-10-01

    Sex trafficking (ST), a contemporary form of female slavery, is a human rights issue of critical concern to social work. The global response to ST has been substantial, and 166 countries have adopted anti-ST legislation. Despite considerable efforts to combat ST, the magnitude is increasing. To date, the majority of anti-ST efforts have focused on criminalization policies that target traffickers or purchasers of sexual services, who are predominantly male; prevention programming and services for predominantly female victims have received less support. Therapeutic services to assist pornography addicts and purchasers of sexual services are also necessary. In this article, authors examine current anti-ST policies, programs, and services, both domestically and globally, and present an innovative paradigm that addresses social inequities and emphasizes prevention programming. They conclude with a discussion of the paradigm's implications for social work policies, practices, and services. PMID:26489349

  12. Sex Trafficking: Policies, Programs, and Services.

    Science.gov (United States)

    Orme, Julie; Ross-Sheriff, Fariyal

    2015-10-01

    Sex trafficking (ST), a contemporary form of female slavery, is a human rights issue of critical concern to social work. The global response to ST has been substantial, and 166 countries have adopted anti-ST legislation. Despite considerable efforts to combat ST, the magnitude is increasing. To date, the majority of anti-ST efforts have focused on criminalization policies that target traffickers or purchasers of sexual services, who are predominantly male; prevention programming and services for predominantly female victims have received less support. Therapeutic services to assist pornography addicts and purchasers of sexual services are also necessary. In this article, authors examine current anti-ST policies, programs, and services, both domestically and globally, and present an innovative paradigm that addresses social inequities and emphasizes prevention programming. They conclude with a discussion of the paradigm's implications for social work policies, practices, and services.

  13. Incunabular Immunological Events in Prion Trafficking

    OpenAIRE

    Michel, Brady; Meyerett-Reid, Crystal; Johnson, Theodore; Ferguson, Adam; Wyckoff, Christy; Pulford, Bruce; Bender, Heather; Avery, Anne; Telling, Glenn; Dow, Steven; Zabel, Mark D.

    2012-01-01

    While prions probably interact with the innate immune system immediately following infection, little is known about this initial confrontation. Here we investigated incunabular events in lymphotropic and intranodal prion trafficking by following highly enriched, fluorescent prions from infection sites to draining lymph nodes. We detected biphasic lymphotropic transport of prions from the initial entry site upon peripheral prion inoculation. Prions arrived in draining lymph nodes cell autonomo...

  14. How globalization facilitates trafficking in persons?

    Directory of Open Access Journals (Sweden)

    Nazafarin Nazemi

    2012-12-01

    Full Text Available Globalization occurs all around us and it has resulted in profound developments in allaspects of human lives. Nevertheless, one should not ignoreits negative contributions also.Unfortunately facilities provided by globalization can be used by good people as well as criminals.One of the dark sides of globalization is exacerbating the illicit trade of people and their parts. Thisarticle reviews some of the issues regarding these two concepts and reveals that how globalization canfacilitate trafficking in human beings.

  15. THE PROBLEM OF INTERNATIONAL DRUG TRAFFICKING

    OpenAIRE

    Kuzmina, V. M.

    2015-01-01

    The illegal drug trade is a global black market dedicated to the cultivation, manufacture, distribution and sale of drugs that are subjected to drug prohibition laws. Most jurisdictions prohibit trade, except under license of many types of drugs through the use of drug prohibition laws. Today, drug trafficking is a very profitable business and at the same time it requires great ingenuity during its transit.

  16. Trafficking in migrants: a european perspective

    OpenAIRE

    Di Nicola, Andrea

    2000-01-01

    This essay, first of all, seeks to answer questions related to the problem of the traffic of migrants in Europe: are there organised criminal groups active in the continent who concern themselves with human trafficking and if so which groups? How do they organise their traffic? Which routes are most widely used in order to perform this criminal activity? These questions will be dealt with under a particular light: while answering them, the author will try to give a framework, though very gene...

  17. Leukocyte trafficking in alveoli and airway passages

    OpenAIRE

    Doerschuk Claire M

    2000-01-01

    Abstract Many pulmonary diseases preferentially affect the large airways or the alveoli. Although the mechanisms are often particular to each disease process, site-specific differences in leukocyte trafficking and the regulation of inflammation also occur. Differences in the process of margination, sequestration, adhesion, and migration occur that can be attributed to differences in anatomy, hemodynamics, and the expression of proteins. The large airways are nourished by the bronchial circula...

  18. Chemokine Receptors and Transplantation

    Institute of Scientific and Technical Information of China (English)

    Jinquan Tan; Gang Zhou

    2005-01-01

    A complex process including both the innate and acquired immune responses results in allograft rejection. Some chemokine receptors and their ligands play essential roles not only for leukocyte migration into the graft but also in facilitating dendritic and T cell trafficking between lymph nodes and the transplant in the early and late stage of the allogeneic response. This review focuses on the impact of these chemoattractant proteins on transplant outcome and novel diagnostic and therapeutic approaches for antirejection therapy based on targeting of chemokine receptors and/or their ligands. Cellular & Molecular Immunology.

  19. [Autoimmune mechanisms of modulation of the activity of glutamate receptors in children with epilepsy and craniocerebral injury].

    Science.gov (United States)

    Pinelis, V G; Sorokina, E G

    2008-01-01

    The role of glutamate receptors and their hyperstimulation in the development of autoimmune processes is discussed with reference to brain pathology associated with hypoxia and ischemia. Epilepsy, paroxismal condition, and craniocerebral injury (CCI) in children are shown to be accompanied by a rise in the levels of antibodies against AMPA and NMDA receptors of glutamate and nitric oxide markers (cGMP, nitrates + nitrites). Also enhanced in epilepsy and paroxismal condition are the levels of cGMP and antibodies against AMPA(GluR1) receptors of glutamate. Acute CCI period is characterized by a marked change in the levels of NO metabolites and antibodies to two subtypes of glutamate receptor, AMPA and NMDA. The levels of antibodies to NMDA(NR2A) receptors are significantly different within 1 day after CCI depending on its outcome. Unfavourable outcome of CCI is associated with the lowest level of antibodies and high NO metabolite content. Relationship between the levels of NO and antibodies against glutamate receptors is discussed with the use of experimental data. It is concluded that antibodies to glutamate receptors and receptor hyperstimulation play an important role in pathogenesis of hypoxia. PMID:19189459

  20. Pharmacological and structural characterization of conformationally restricted (S)-glutamate analogues at ionotropic glutamate receptors

    DEFF Research Database (Denmark)

    Juknaite, Lina; Venskutonyte, Raminta; Assaf, Zeinab;

    2012-01-01

    at NMDA receptors, where the introduction of the carbocyclic ring is expected to lead to a steric clash with binding site residues. CBG-IV was demonstrated to be an agonist at both GluA2 and the kainate receptor GluK1. CBG-IV showed high affinity binding to GluK1 compared to GluA2, GluK2 and GluK3, which......Conformationally restricted glutamate analogues have been pharmacologically characterized at AMPA and kainate receptors and the crystal structures have been solved of the ligand (2S,1'R,2'S)-2-(2'-carboxycyclobutyl)glycine (CBG-IV) in complex with the ligand binding domains of the AMPA receptor Glu......A2 and the kainate receptor GluK3. These structures show that CBG-IV interacts with the binding pocket in the same way as (S)-glutamate. The binding affinities reveal that CBG-IV has high affinity at the AMPA and kainate receptor subtypes. Appreciable binding affinity of CBG-IV was not observed...

  1. Nuclear Trafficking During Plant Innate Immunity

    Institute of Scientific and Technical Information of China (English)

    Jun Liu; Gitta Coaker

    2008-01-01

    Land plants possess innate immune systems that can control resistance against pathogen infection. Conceptually, there are two branches of the plant innate immune system. One branch recognizes conserved features of microbial pathogens, while a second branch specifically detects the presence of pathogen effector proteins by plant resistance (R) genes. Innate immunity controlled by plant R genes is called effector-triggered immunity. Although R genes can recognize all classes of plant pathogens, the majority can be grouped into one large family, encoding proteins with a nucleotide binding site and C-terminal leucine rich repeat domains. Despite the importance and number of R genes present in plants, we are just beginning to decipher the signaling events required to initiate defense responses. Recent exciting discoveries have implicated dynamic nuclear trafficking of plant R proteins to achieve effector-triggered immunity. Furthermore, there are several additional lines of evidence implicating nucleo-cyctoplasmic trafficking in plant disease resistance, as mutations in nucleoporins and importins can compromise resistance signaling. Taken together, these data illustrate the importance of nuclear trafficking in the manifestation of disease resistance mediated by R genes.

  2. P2X receptors.

    Science.gov (United States)

    North, R Alan

    2016-08-01

    Extracellular adenosine 5'-triphosphate (ATP) activates cell surface P2X and P2Y receptors. P2X receptors are membrane ion channels preferably permeable to sodium, potassium and calcium that open within milliseconds of the binding of ATP. In molecular architecture, they form a unique structural family. The receptor is a trimer, the binding of ATP between subunits causes them to flex together within the ectodomain and separate in the membrane-spanning region so as to open a central channel. P2X receptors have a widespread tissue distribution. On some smooth muscle cells, P2X receptors mediate the fast excitatory junction potential that leads to depolarization and contraction. In the central nervous system, activation of P2X receptors allows calcium to enter neurons and this can evoke slower neuromodulatory responses such as the trafficking of receptors for the neurotransmitter glutamate. In primary afferent nerves, P2X receptors are critical for the initiation of action potentials when they respond to ATP released from sensory cells such as taste buds, chemoreceptors or urothelium. In immune cells, activation of P2X receptors triggers the release of pro-inflammatory cytokines such as interleukin 1β. The development of selective blockers of different P2X receptors has led to clinical trials of their effectiveness in the management of cough, pain, inflammation and certain neurodegenerative diseases.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'. PMID:27377721

  3. PREVENTION OF HUMAN TRAFFICKING CONDUCTED AT SECONDARY SCHOOLS

    OpenAIRE

    Králová, Martina

    2009-01-01

    Even though 79% of the surveyed students claim they have heard the term ``human trafficking{\\crq}q, only 14% can define this term accurately. On the basis of the information obtained, a conclusion was arrived at that the level of information about human trafficking among students at Kolín-district secondary schools is inadequate. The students themselves said in their opinions that they did not have enough information about human trafficking, thus confirming this fact. The benefit and sense of...

  4. Conventional capital, criminal capital, and criminal careers in drug trafficking

    OpenAIRE

    Wang, Wei

    2013-01-01

    Although the criminal career paradigm has explored various crime types, little effort has been conducted to systematically examine the pattern of drug trafficking careers. Ethnographic studies on drug trafficking have proposed that different forms of capital have an impact on the patterns of drug trafficking careers. The effects of conventional and criminal capital, however, have been the subject of much less empirical attention. Drawing from information on the criminal careers of 182 incarce...

  5. Prohibiting Sex Purchasing and Ending Trafficking : The Swedish Prostitution Law

    OpenAIRE

    Waltman, Max

    2011-01-01

    The Swedish prostitution law from 1999, now followed by Norway and Iceland, criminalized the purchaser and decriminalized the prostituted person. This is analyzed as a cogent state response under international trafficking law, particularly to the obligations set forth in the United Nation’s Trafficking Protocol from 2000. The Protocol states that a person is regarded a trafficking victim when, e.g., someone abuses her “position of vulnerability” in order to exploit her. International jurispru...

  6. The Governance Institutions of a Drug Trafficking Organization

    OpenAIRE

    Kostelnik, James; Skarbek, David

    2013-01-01

    How do drug trafficking organizations organize? Drug trafficking organizations continue to operate effectively despite incentives for members to defect, pressure from damaged communities, and government interdiction efforts. This paper identifies the problem of defection in this context and applies insights from the literatures on club goods and extralegal governance institutions to explain the puzzling organization and activities of one of Mexico’s most dangerous drug trafficking organizatio...

  7. Accountability and the Use of Raids to Fight Trafficking

    Directory of Open Access Journals (Sweden)

    Melissa Ditmore

    2012-09-01

    Full Text Available Accountability in anti-trafficking efforts is a crucial but often overlooked aspect of deciding whether such efforts are truly rooted in a human rights framework. In a rush to help, and inspired by sensationalised views of what human trafficking is, many campaigns actually harm the very people they are supposed to assist. Law enforcement raids are one such effort, as they do not take into account the very different power dynamics between the actor engaging in the raid, and the person who is subject to the raid. Data from the United States suggests that raids conducted by local law enforcement agencies are an ineffective means of locating and identifying trafficked persons. Research also reveals that raids are all too frequently accompanied by violations of the human rights of trafficked persons and sex workers alike, and can therefore be counterproductive to the underlying goals of anti-trafficking initiatives. Findings suggest that a rights-based and “survivor-centred” approach to trafficking in persons requires the development and promotion of alternative methods of identifying and protecting the rights of trafficked persons which prioritise the needs, agency, and self-determination of trafficking survivors. They also indicate that preventative approaches, which address the circumstances that facilitate trafficking in persons, should be pursued over law enforcement based responses.

  8. Trafficking in Human Beings in the European Union

    Directory of Open Access Journals (Sweden)

    Donna M. Hughes

    2014-10-01

    Full Text Available In this article, the intersection of gender, trafficking for sexual exploitation, and use of digital communication technologies are analyzed based on data from the European Union (EU. Over the past two decades, an increase in trafficking in human beings in the EU has been accompanied by an increase in the development and availability of digital communication technologies. The first statistical analysis of trafficking in human beings (2008-2010 carried out by the European Commission found 23,632 victims of human trafficking in the reporting member states. Eighty percent of victims were women and girls; 20% were men and boys. The majority of the victims (62% were trafficked for sexual exploitation. Digital communication technologies are widely used for trafficking for sexual exploitation, and more rarely for trafficking for forced labor. This article concludes that the combination of gender, trafficking for sexual exploitation, and use of digital communication technologies has created a nexus of victimization for women and girls. Based on this analysis and other sources of information, the European region is the world’s leading region for trafficking for sexual exploitation.

  9. Human Trafficking and Commercialization of Surrogacy in India

    Directory of Open Access Journals (Sweden)

    Pyali Chatterjee

    2014-10-01

    Full Text Available The Supreme Court of India, In Baby Manji Yamada versus Union of India & Anr. [2008] INSC 1656, popularly known as Manji Case, declared that Commercial Surrogacy is legal in India. As we know that, India is a developing country and here, most of the peoples are very poor and illiterate. Recently, human trafficking was increase with an uncontrollable rate in the entire world. In addition, making Commercialization of Surrogacy legal had already give birth to a new form of trafficking. Where, illiterate women from poor section is trafficked to run the reproductive industry of the Surrogacy. As we know that the traffickers, they used to trafficked girls/women for prostitution but now after the legalization of Commercial Surrogacy, they will trafficked girl/women for the reproductive industry as a raw material. The Immoral Trafficking Prevention Act (ITPA, 1956 and Sections 366(A and 372 of the Indian Penal Code, 1860 are the existing laws of India, which deals with human trafficking. However, none of these provisions contains any solution, to deal with this new serious issue of trafficking of women/girls for the purpose of Commercial Surrogacy in reproductive industries. These existing laws as well as the pending draft bill of Assisted Reproductive Technologies (ART Regulation Bill, 2010 needs an amendment to check this crime against women once again to protect the rights and health of the women.

  10. Structural mechanism of glutamate receptor activation and desensitization.

    Science.gov (United States)

    Meyerson, Joel R; Kumar, Janesh; Chittori, Sagar; Rao, Prashant; Pierson, Jason; Bartesaghi, Alberto; Mayer, Mark L; Subramaniam, Sriram

    2014-10-16

    Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the vertebrate brain. To gain a better understanding of how structural changes gate ion flux across the membrane, we trapped rat AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) and kainate receptor subtypes in their major functional states and analysed the resulting structures using cryo-electron microscopy. We show that transition to the active state involves a 'corkscrew' motion of the receptor assembly, driven by closure of the ligand-binding domain. Desensitization is accompanied by disruption of the amino-terminal domain tetramer in AMPA, but not kainate, receptors with a two-fold to four-fold symmetry transition in the ligand-binding domains in both subtypes. The 7.6 Å structure of a desensitized kainate receptor shows how these changes accommodate channel closing. These findings integrate previous physiological, biochemical and structural analyses of glutamate receptors and provide a molecular explanation for key steps in receptor gating. PMID:25119039

  11. Modelling fate and transport of glyphosate and AMPA in the Meuse catchment to assess the contribution of different pollution sources

    Science.gov (United States)

    Desmet, Nele; Seuntjens, Piet

    2013-04-01

    Large river basins have multiple sources of pesticides and usually the pollution sources are spread over the entire catchment. The cumulative effect of pesticides entering the river system in upstream areas and the formation of persistent degradation products can compromise downstream water use e.g. raw water quality for drinking water abstractions. For assessments at catchment scale pesticide fluxes coming from different sources and sub basins need to be taken into account. To improve management strategies, a sound understanding of the sources, emission routes, transport, environmental fate and conversion of pesticides is needed. In the Netherlands, the Meuse river basin is an important source for drinking water production. The river suffers from elevated concentrations of glyphosate and aminomethylphosphonic acid (AMPA). For AMPA it is rather unclear to what extent the pollution is related to glyphosate degradation and what is the contribution of other sources, especial phosphonates in domestic and industrial waste water. Based on the available monitoring data only it is difficult to distinguish between AMPA sources in such a large river basin. This hampers interpretation and decision making for water quality management in the Meuse catchment. Here, application of water quality models is very useful to obtain complementary information and insights. Modelling allows accounting for temporal and spatial variability in discharge and concentrations as well as distinguishing the contribution from conversion processes. In this study, a model for the river Meuse was developed and applied to assess the contribution of tributary and transnational influxes, glyphosate degradation and other sources to the AMPA pollution.

  12. Glyphosate-resistant and conventional canola (Brassica napus L.)responses to glyphosate and Aminomethylphosphonic Acid (AMPA) treatment

    Science.gov (United States)

    Glyphosate-resistant (GR) canola expresses two transgenes: 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-enolpyruvylshiki...

  13. Acoustic trauma slows AMPA receptor‐mediated EPSCs in the auditory brainstem, reducing GluA4 subunit expression as a mechanism to rescue binaural function

    Science.gov (United States)

    Pilati, Nadia; Linley, Deborah M.; Selvaskandan, Haresh; Uchitel, Osvaldo; Hennig, Matthias H.; Kopp‐Scheinpflug, Cornelia

    2016-01-01

    Key points Lateral superior olive (LSO) principal neurons receive AMPA receptor (AMPAR) ‐ and NMDA receptor (NMDAR)‐mediated EPSCs and glycinergic IPSCs.Both EPSCs and IPSCs have slow kinetics in prehearing animals, which during developmental maturation accelerate to sub‐millisecond decay time‐constants. This correlates with a change in glutamate and glycine receptor subunit composition quantified via mRNA levels.The NMDAR‐EPSCs accelerate over development to achieve decay time‐constants of 2.5 ms. This is the fastest NMDAR‐mediated EPSC reported.Acoustic trauma (AT, loud sounds) slow AMPAR‐EPSC decay times, increasing GluA1 and decreasing GluA4 mRNA.Modelling of interaural intensity difference suggests that the increased EPSC duration after AT shifts interaural level difference to the right and compensates for hearing loss.Two months after AT the EPSC decay times recovered to control values.Synaptic transmission in the LSO matures by postnatal day 20, with EPSCs and IPSCs having fast kinetics. AT changes the AMPAR subunits expressed and slows the EPSC time‐course at synapses in the central auditory system. Abstract Damaging levels of sound (acoustic trauma, AT) diminish peripheral synapses, but what is the impact on the central auditory pathway? Developmental maturation of synaptic function and hearing were characterized in the mouse lateral superior olive (LSO) from postnatal day 7 (P7) to P96 using voltage‐clamp and auditory brainstem responses. IPSCs and EPSCs show rapid acceleration during development, so that decay kinetics converge to similar sub‐millisecond time‐constants (τ, 0.87 ± 0.11 and 0.77 ± 0.08 ms, respectively) in adult mice. This correlated with LSO mRNA levels for glycinergic and glutamatergic ionotropic receptor subunits, confirming a switch from Glyα2 to Glyα1 for IPSCs and increased expression of GluA3 and GluA4 subunits for EPSCs. The NMDA receptor (NMDAR)‐EPSC decay τ accelerated from >40 ms in

  14. South Asia in Action: Preventing and responding to child trafficking. Analysis of anti-trafficking initiatives in the region

    OpenAIRE

    UNICEF Innocenti Research Centre

    2009-01-01

    This publication provides a regional analysis of anti-trafficking measures relevant to children in the countries of South Asia. It assesses national legal and policy frameworks and provides a list of recommended actions for the application of a rights-based approach to child trafficking. Emphasis is placed on the indivisibility of human rights and the influence that trafficking, exploitation and abuse have on children’s enjoyment of rights and fundamental freedoms.The study is based on the un...

  15. INDIVIDUAL EMPOWERMENT EXPERIENCES OF TRAFFICKED RETURNEES : Post Integration Lives of Sex Trafficked Returnees in Mid-Western Nepal

    OpenAIRE

    Limbu, Lekh Nath; Shahi, Hari Jung

    2014-01-01

    Lekh Nath Limbu and Hari Jung Shahi. Individual Empowerment Experiences of Trafficked Returnees: Post Integration Lives of Sex Trafficked Returnees in Mid-Western Nepal. Diak South, Helsinki, Finland. Autumn 2014. 71 Pages. 1 Appendix. Language: English. Diaconia University of Applied Sciences. Degree programme in Social Services and Community Development. Degree: Bachelor of Social Services. This study discusses the empowerment experiences of sex trafficked returnees. By doing so, th...

  16. The rab11 effector protein FIP1 regulates adiponectin trafficking and secretion.

    Directory of Open Access Journals (Sweden)

    Brian P Carson

    Full Text Available Adiponectin is an adipokine secreted by white adipocytes involved in regulating insulin sensitivity in peripheral tissues. Secretion of adiponectin in adipocytes relies on the endosomal system, however, the intracellular machinery involved in mediating adiponectin release is unknown. We have previously reported that intracellular adiponectin partially compartmentalizes with rab 5 and rab11, markers for the early/sorting and recycling compartments respectively. Here we have examined the role of several rab11 downstream effector proteins (rab11 FIPs in regulating adiponectin trafficking and secretion. Overexpression of wild type rab11 FIP1, FIP3 and FIP5 decreased the amount of secreted adiponectin expressed in HEK293 cells, whereas overexpression of rab11 FIP2 or FIP4 had no effect. Furthermore shRNA-mediated depletion of FIP1 enhanced adiponectin release whereas knock down of FIP5 decreased adiponectin secretion. Knock down of FIP3 had no effect. In 3T3L1 adipocytes, endogenous FIP1 co-distributed intracellularly with endogenous adiponectin and FIP1 depletion enhanced adiponectin release without altering insulin-mediated trafficking of the glucose transporter Glut4. While adiponectin receptors internalized with transferrin receptors, there were no differences in transferrin receptor recycling between wild type and FIP1 depleted adipocytes. Consistent with its inhibitory role, FIP1 expression was decreased during adipocyte differentiation, by treatment with thiazolidinediones, and with increased BMI in humans. In contrast, FIP1 expression increased upon exposure of adipocytes to TNFα. In all, our findings identify FIP1 as a novel protein involved in the regulation of adiponectin trafficking and release.

  17. Endocytic trafficking of laminin is controlled by dystroglycan and is disrupted in cancers.

    Science.gov (United States)

    Leonoudakis, Dmitri; Huang, Ge; Akhavan, Armin; Fata, Jimmie E; Singh, Manisha; Gray, Joe W; Muschler, John L

    2014-11-15

    The dynamic interactions between cells and basement membranes serve as essential regulators of tissue architecture and function in metazoans, and perturbation of these interactions contributes to the progression of a wide range of human diseases, including cancers. Here, we reveal the pathway and mechanism for the endocytic trafficking of a prominent basement membrane protein, laminin-111 (referred to here as laminin), and their disruption in disease. Live-cell imaging of epithelial cells revealed pronounced internalization of laminin into endocytic vesicles. Laminin internalization was receptor mediated and dynamin dependent, and laminin proceeded to the lysosome through the late endosome. Manipulation of laminin receptor expression revealed that the dominant regulator of laminin internalization is dystroglycan, a laminin receptor that is functionally perturbed in muscular dystrophies and in many cancers. Correspondingly, laminin internalization was found to be deficient in aggressive cancer cells displaying non-functional dystroglycan, and restoration of dystroglycan function strongly enhanced the endocytosis of laminin in both breast cancer and glioblastoma cells. These results establish previously unrecognized mechanisms for the modulation of cell-basement-membrane communication in normal cells and identify a profound disruption of endocytic laminin trafficking in aggressive cancer subtypes. PMID:25217627

  18. An oligodeoxynucleotide with CCT repeats restrains CpG ODN-induced TLR9 trafficking.

    Science.gov (United States)

    Zhang, Xiaoling; Sun, Wei; Wu, Xiuli; Wang, Hua; Yan, Youyou; Guo, Sheng; Song, Dandan; Li, Hainan; Gao, Shuang; Wang, Luowei; Yu, Yongli; Wang, Liying

    2014-01-01

    Toll-like receptor 9 (TLR9) can sense pathogen DNA and CpG ODN or even self-DNA by trafficking assisted by Unc93B1, an endoplasmic reticulum (ER) transmembrane protein, from ER to endolysosomes or cell surface. In previous study, we found that an oligodeoxynucleotide with CCT repeats (SAT05f) could selectively inhibit TLR7/9 activation. However, the mechanism for the inhibitory activity of SAT05f is still unknown. In present research, it was found that SAT05f could inhibit CpG ODN-induced the intracellular trafficking of TLR9 and Unc93B1 with feedback the responses of decreased surface TLR9 and enhanced TLR9 mRNA expression but not influence TLR9 protein level by using human plasmacytoid dendritic cell line CAL-1 cells, suggesting that SAT05f inhibits TLR9 activation by restraining TLR9 trafficking. Since the mitochondrial DNA released from injured tissue can cause systemic inflammatory response syndrome (SIRS), this study may provide valuable data for prevention and treatment of SIRS and rescue severe trauma patients. PMID:25374030

  19. LRP1 controls biosynthetic and endocytic trafficking of neuronal prion protein

    DEFF Research Database (Denmark)

    Parkyn, Celia J; Vermeulen, Esmeralda G M; Mootoosamy, Roy C;

    2008-01-01

    The trafficking of normal cellular prion protein (PrP(C)) is believed to control its conversion to the altered conformation (designated PrP(Sc)) associated with prion disease. Although anchored to the membrane by means of glycosylphosphatidylinositol (GPI), PrP(C) on neurons is rapidly and consti......The trafficking of normal cellular prion protein (PrP(C)) is believed to control its conversion to the altered conformation (designated PrP(Sc)) associated with prion disease. Although anchored to the membrane by means of glycosylphosphatidylinositol (GPI), PrP(C) on neurons is rapidly...... required for this process. Moreover, sustained inhibition of LRP1 levels by siRNA leads to the accumulation of PrP(C) in biosynthetic compartments, with a concomitant lowering of surface PrP(C), suggesting that LRP1 expedites the trafficking of PrP(C) to the neuronal surface. PrP(C) and LRP1 can be co......-immunoprecipitated from the endoplasmic reticulum in normal neurons. The N-terminal domain of PrP(C) binds to purified human LRP1 with nanomolar affinity, even in the presence of 1 microM of the LRP-specific chaperone, receptor-associated protein (RAP). Taken together, these data argue that LRP1 controls both the surface...

  20. Globalization and the illicit market for human trafficking : an empirical analysis of supply and demand

    OpenAIRE

    Danailova-Trainor, Gergana; Belser, Patrick

    2006-01-01

    Using the ILO's database constructed for the purpose of its global estimate on trafficking and forced labour, examines the determinants of one specific form of human trafficking, namely trafficking for forced sexual exploitation.