DOCSLIB.ORG

Poster Abstracts

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Poster Abstracts POSTER ABSTRACTS Society of Toxicology (MASOT) www.masot.org Fall 2015 Scientific Meeting October 13th, 2015 Abstract 01 Tracking Inflammatory Macrophage Accumulation in the Lung during Ozone- induced Lung Injury in Mice M Francis, M Mandal, C. Sun, H Choi, JD Laskin, DL Laskin Rutgers University, Piscataway, NJ Ozone induced lung injury is associated with an accumulation of pro- and antiinflammatory macrophages (MP) in the lung which have been implicated in tissue injury and repair. In these studies, we used in vivo tracking techniques to investigate the origin of cell. Initially we generated bone marrow (BM) chimeric mice by adoptive transfer of BM cells from GFP+ mice into irradiated C57BL/6 mice. After 4 weeks, mice were exposed to air or ozone (0.8 ppm, 3 h). Macrophages were isolated from lungs 24- 72 h later, stained with fluorescent labeled antibodies, and analyzed by flow cytometry. Approximately 98% of BM cells were found to be GFP+ while only 5% were GFP+ in control lungs. Ozone exposure resulted in a marked increase in infiltrating mature GFP+CD11b+F4/80+ MP into the lung. Two populations, Ly6CHi proinflammatory and Ly6CLo antiinflammatory were identified. Proinflammatory GFP+Ly6CHi MP increased rapidly after ozone and remained elevated, increases in antiinflammatory GFP+Ly6CLo were transient. To assess potential mechanisms mediating the accumulation of these MP subpopulations in the lung, we used mice lacking Ccr2, a chemokine receptor involved in proinflammatory MP trafficking. Loss of Ccr2 resulted in decreased numbers of infiltrating CD11b+ MP in the lung. This was due to a selective reduction in proinflammatory Ly6CHi MP. Loss of Ccr2 also resulted in an increased expression of Lo the fractalkine receptor Cx3CR1; this was correlated with an increase in Ly6C anti- inflammatory MP in the lung and reduced toxicity. To further characterize these cells, GFP/+ GFP+ we used CX3CR1 mice. After ozone exposure, CX3CR1 cells infiltrated into the lung; these cells were F4/80+ and expressed CD206, a marker of antiinflammatory MP. Taken together, these results demonstrate that following ozone exposure, inflammatory cells enter the lung from the bone marrow. Additionally, while Ccr2 plays a key role in proinflammatory MP trafficking to the lung, CX3CR1 is involved in antiinflammatory MP migration. Supported by NIH Grants ES004738, CA132624, AR055073, ES007148 and ES005022. Abstract 02 Pharmacological Modulation of GRM1 Activation by Riluzole Results in a Reduction in Exosome Levels in Melanoma Allison L. Isola1,2, Yvonne Wen3, James Goydos3 and Suzie Chen1,2,3 1 Susan Lehman Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers, the State University, Piscataway, NJ, 08854; 2 Joint Graduate Program of Toxicology, Rutgers, the State University, Piscataway, NJ, 08854; 3 Rutgers, the Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ, 08903 Exosomes are naturally occurring small membrane enclosed nanovesicles generated and released constitutively by various cell types, and are more frequently released by tumor cells. The normal functions of exosomes include transporting proteins, nucleic acids and may facilitate communication between cells within the local microenvironment. Recently, several reports postulated the involvement of exosomes in tumor cell metastases including melanoma. Metabotropic glutamate receptor 1 (GRM1), a neuronal receptor, when ectopically expressed in melanocytes, is sufficient to induce melanocyte transformation in vitro and spontaneous malignant melanoma development in vivo in a transgenic mouse model. GRM1-transformed melanocytes exhibited abundant level of exosomes compared to normal melanocytes evaluated by electron microscopy, CD-63, a protein marker of exosomes, and Nanosight. Similar results were observed in GRM1-expressing human melanoma cells. Modulation of GRM1 expression levels by genetic (via silencing RNA) or pharmacological (inhibitor of GRM1-mediated glutamate signaling) means led to a reduction in cell growth in vitro and tumor progression in vivo. Furthermore, concurrent reduction in exosomal production/secretion was observed, while an increase in GRM1 expression by exogenous GRM1 cDNA resulted in parallel enhancement in exosomal production/secretion. Possible involvement of exosomes in promoting the metastatic phenotypes detected in our melanoma prone transgenic mice provides opportunities to explore this notion directly. Whether GRM1 regulates exosome production directly, via its signaling cascade, or by another route, is currently being investigated. Abstract 03 Down-Regulation of the Human Placental BCRP/ABCG2 Transporter in Response to Hypoxia Ludwik Gorczyca1,2, Jianyao Du4, Lissa Francois, Kristin Bircsak1,2, Xia Wen1, Lauren Aleksunes1,3 1Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ; 2Joint Graduate Program in Toxicology, Rutgers University, Piscataway, NJ; 3Enviornmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ; 4China Pharmaceutical University, Nanjing, Jiangsu, People’s Republic of China The Breast Cancer Resistance Protein (BCRP/ABCG2) is expressed on the apical membrane of placental syncytiotrophoblasts and serves an important role in protecting the fetus from in utero chemical and drug exposure. BCRP actively limits the passage of drugs and xenobiotics across the placenta by expelling them back into maternal circulation. Recent studies have shown conflicting data in terms of BCRP transporter expression in response to altered oxygen tension. The partial oxygen pressure in the first and second trimester human placenta is approximately 20 mmHg (~3% O2) and 60 mmHg (~8% O2), respectively, and continues to increase to 20% throughout pregnancy. To assess how hypoxia affects the expression and regulation of the BCRP/ABCG2 transporter, BeWo choriocarcinoma cells were exposed to 3%, 8%, and 20% oxygen for 24 hours. mRNA and protein expression of BCRP and potential transcription factors involved in its regulation were assessed by qPCR and western blot. Hypoxia increased the mRNA expression of two HIF-1a prototypical target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT-1), confirming the activation of this signaling pathway. Placental BeWo cells, exposed to low oxygen tension, exhibited a dose-dependent down-regulation of BCRP mRNA and protein (~25-35%) when compared to normoxic conditions (20% O2). Screening of potential regulators of BCRP mRNA during hypoxia revealed a significant down-regulation of nuclear receptors PPARg, RXRa as well as transcription factors AhR and NRF2, compared to normoxia. On the other hand, in response to 3% and 8% O2 tension the expression of the nuclear receptor ERa was induced 6 and 2 fold, respectively. Together these data suggest that placental expression of the BCRP efflux transporter is regulated by oxygen tension, and that the fetus may be at higher risk of exposure to BCRP substrates during early pregnancy. Abstract 04 Nitrogen Mustard Induces DNA Damage and Structural Changes in Mouse Skin Hair Follicles G. Composto1, S. Kim1, D. Heck2, J. Laskin1, D. Laskin1 and L. Joseph1 1Rutgers University, Piscataway, NJ and 2New York Medical College, Valhalla, NY Nitrogen mustard (NM) is a potent skin vesicant. Evidence suggests that the pilosebaceous unit in the skin is a target for NM. To assess this, we analyzed changes in hair follicles and sebaceous glands in mouse skin following NM exposure. Dorsal skin of female CD-1 mice was exposed to 77 ng NM for 6 min, and harvested 1-5 d later. Control (CTL) skin contained sebaceous glands expressing fatty acid synthase (FAS), a marker for sebum production. Proliferating cell nuclear antigen (PCNA, marker of cellular division) and keratin-10 (K-10, marker of cellular differentiation) were expressed in the hair outer root sheath (ORS) and infundibulum of CTL skin. One d post NM, FAS, PCNA and K-10 expression was decreased in sebaceous glands, ORS, and infundibulum, respectively, while phospho-H2A.X, a marker for double strand DNA breaks, was evident in the ORS and basal epidermis. By 2 d, an eschar formed; there were reduced numbers of pilosebaceous units within the eschar and this was associated with increased expression of phospho-H2A.X in hyperplastic interfollicular epidermis (IFE). Three days post-NM, low levels of FAS, PCNA, and K-10 were expressed in the pilosebaceous units at the wound edge. By 4 d, small pilosebaceous units within the neo-epidermis expressed increased levels of FAS, PCNA and K-10, while decreased levels of phospho-H2A.X were observed within the IFE. By 5 d, wound healing was evident with increased FAS and K-10 expression in the sebaceous glands and infundibulum, respectively. PCNA was also increased in the ORS, while phospho- H2A.X was decreased. These data indicate that the pilosebaceous unit is an important target contributing to NM-induced skin injury. Support: NIH AR055073. Abstract 05 Genistein Reduces Glyburide Efflux by the Human Placental BCRP Transporter: Transcriptional Regulation and Direct Inhibition Kristin M Bircsak1,2, Yixin Lin1, Lauren M Aleksunes1 1Dept of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ and 2Joint Graduate Program in Toxicology, Rutgers University, Piscataway, NJ The hypoglycemic drug glyburide is routinely used in the treatment of gestational diabetes. Fetal exposure to glyburide is typically low because the BCRP/ABCG2 transporter on placental syncytiotrophoblasts prevents its
Load more

Recommended publications
  • Synthesis of Conformationally Constrained Glutamate Analogues and Their Preliminary Evaluation As Glutamate Transport Inhibitors
    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 2002 Synthesis of conformationally constrained glutamate analogues and their preliminary evaluation as glutamate transport inhibitors Travis Taylor Denton The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Denton, Travis Taylor, "Synthesis of conformationally constrained glutamate analogues and their preliminary evaluation as glutamate transport inhibitors" (2002). Graduate Student Theses, Dissertations, & Professional Papers. 9450. https://scholarworks.umt.edu/etd/9450 This Dissertation is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.
    [Show full text]
  • The Microbiota-Produced N-Formyl Peptide Fmlf Promotes Obesity-Induced Glucose
    Page 1 of 230 Diabetes Title: The microbiota-produced N-formyl peptide fMLF promotes obesity-induced glucose intolerance Joshua Wollam1, Matthew Riopel1, Yong-Jiang Xu1,2, Andrew M. F. Johnson1, Jachelle M. Ofrecio1, Wei Ying1, Dalila El Ouarrat1, Luisa S. Chan3, Andrew W. Han3, Nadir A. Mahmood3, Caitlin N. Ryan3, Yun Sok Lee1, Jeramie D. Watrous1,2, Mahendra D. Chordia4, Dongfeng Pan4, Mohit Jain1,2, Jerrold M. Olefsky1 * Affiliations: 1 Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, La Jolla, California, USA. 2 Department of Pharmacology, University of California, San Diego, La Jolla, California, USA. 3 Second Genome, Inc., South San Francisco, California, USA. 4 Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA. * Correspondence to: 858-534-2230, [email protected] Word Count: 4749 Figures: 6 Supplemental Figures: 11 Supplemental Tables: 5 1 Diabetes Publish Ahead of Print, published online April 22, 2019 Diabetes Page 2 of 230 ABSTRACT The composition of the gastrointestinal (GI) microbiota and associated metabolites changes dramatically with diet and the development of obesity. Although many correlations have been described, specific mechanistic links between these changes and glucose homeostasis remain to be defined. Here we show that blood and intestinal levels of the microbiota-produced N-formyl peptide, formyl-methionyl-leucyl-phenylalanine (fMLF), are elevated in high fat diet (HFD)- induced obese mice. Genetic or pharmacological inhibition of the N-formyl peptide receptor Fpr1 leads to increased insulin levels and improved glucose tolerance, dependent upon glucagon- like peptide-1 (GLP-1). Obese Fpr1-knockout (Fpr1-KO) mice also display an altered microbiome, exemplifying the dynamic relationship between host metabolism and microbiota.
    [Show full text]
  • Microglial Glutathione and Glutamate: Regulation Mechanisms
    Microglial glutathione and glutamate: Regulation mechanisms Victoria Anne Honey Fry UCL Institute of Neurology A thesis submitted for the degree of Doctor of Philosophy (Ph.D.) 1 I, Victoria Fry, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. 2 Abstract Microglia, the immune cells of the central nervous system (CNS), are important in the protection of the CNS, but may be implicated in the pathogenesis of neuroinflammatory disease. Upon activation, microglia produce reactive oxygen and nitrogen species; intracellular antioxidants are therefore likely to be important in their self-defence. Here, it was confirmed that cultured microglia contain high levels of glutathione, the predominant intracellular antioxidant in mammalian cells. The activation of microglia with lipopolysaccharide (LPS) or LPS + interferon- was shown to affect their glutathione levels. GSH levels in primary microglia and those of the BV-2 cell line increased upon activation, whilst levels in N9 microglial cells decreased. - Microglial glutathione synthesis is dependent upon cystine uptake via the xc transporter, which exchanges cystine and glutamate. Glutamate is an excitatory neurotransmitter whose extracellular concentration is tightly regulated by excitatory amino acid transporters, as high levels cause toxicity to neurones and other CNS cell types through overstimulation of - glutamate receptors or by causing reversal of xc transporters. Following exposure to LPS, increased extracellular glutamate and increased levels of messenger ribonucleic acid - (mRNA) for xCT, the specific subunit of xc , were observed in BV-2 and primary microglial cells, suggesting upregulated GSH synthesis.
    [Show full text]
  • Activation of the Metabotropic Glutamate Receptor Attenuates N
    Proc. Natl. Acad. Sci. USA Vol. 88, pp. 9431-9435, November 1991 Neurobiology Activation of the metabotropic glutamate receptor attenuates N-methyl-D-aspartate neurotoxicity in cortical cultures (trans-1-aminocyclopentyl-1,3-dicarboxylic acid/carbachol/Alzheimer disease/development/neurodegeneration) JAE-YOUNG KOH, ELIZABETH PALMER, AND CARL W. COTMAN* Department of Psychobiology, University of California, Irvine, CA 92717 Communicated by James L. McGaugh, July 15, 1991 (receivedfor review April 3, 1991) ABSTRACT Excitatory amino acid receptor-mediated neu- methylisoxazole-4-propionic acid and kainate receptors) are rotoxicity (excitotoxicity) has been proposed to contribute to directly associated with the specific ligand-gated ionophores neuronal loss in a wide variety of neurodegenerative conditions. that permit influx of cations upon activation (ionotropic Although considerable evidence has accumulated implicating receptor). In contrast, the recently discovered metabotropic N-methyl-D-aspartate (NMDA), kainate, and a-amino-3- glutamate, or trans-1-aminocyclopentyl-1,3-dicarboxylic hydroxy-5-methylisoxazole4propionic acid receptors in the acid (ACPD), receptor (10-12) activates a phospholipase, via processes of excitotoxicity, relatively little research has focused a guanine nucleotide-binding regulatory protein, that hydro- on the ability of other neurotransmitter systems to influence lyzes membrane phospholipid to generate the second mes- sengers diacylglycerol (DAG) and inositol trisphosphate excitotoxic neuronal injury. In the present
    [Show full text]
  • Functional Impact of Interacting Protein on Kainate Receptors: Necab1 and Neto Proteins
    Instituto de Neurociencias de Alicante Universidad Miguel Hernandez Thesis manuscript for: PhD in Neuroscience Functional impact of interacting protein on kainate receptors: NeCaB1 and NeTo proteins. Jon Palacios Filardo Supervised by: Prof. Juan Lerma Alicante, 2014 Agradecimientos/Acknowledgments Agradecimientos/Acknowledgments Ahora que me encuentro escribiendo los agradecimientos, me doy cuenta que esta es posiblemente la única sección de la tesis que no será corregida. De manera que los escribiré tal como soy, tal vez un poco caótico. En primer lugar debo agradecer al profesor Juan Lerma, por la oportunidad que me brindó al permitirme realizar la tesis en su laboratorio. Más que un jefe ha sido un mentor en todos estos años, 6 exactamente, en los que a menudo al verme decía: “Jonny cogió su fusil”, y al final me entero que es el título de una película de cine… Pero aparte de un montón de anécdotas graciosas, lo que guardaré en la memoria es la figura de un mentor, que de ciencia todo lo sabía y le encantaba compartirlo. Sin duda uno no puede escribir un libro así (la tesis) sin un montón de gente alrededor que te enseña y ayuda. Como ya he dicho han sido 6 años conviviendo con unos maravillosos compañeros, desde julio de 2008 hasta presumiblemente 31 de junio de 2014. De cada uno de ellos he aprendido mucho; técnicamente toda la electrofisiología se la debo a Ana, con una paciencia infinita o casi infinita. La biología molecular me la enseñó Isa. La proteómica la aprendí del trío Esther-Ricado-Izabella. Joana y Ricardo me solventaron mis primeras dudas en el mundo de los kainatos.
    [Show full text]
  • Tuesday, Symposium: Cortical Sources . . . 37 Symposium 4
    Tuesday, Symposium: Cortical sources . 37 MET,BOLICPVMP~NG IN INSECT LKSCIE ,WD RESTING MEMBRXW ELECTROGENESIS Comparison of electrical activity and ionic currents in an isolated M.J. KATKOWSKA & B. GRAPEL. N. Copernicus Univ., Inst. of Biology and axon and in an isolated neuron. Environmental Protection. Dept. of Animal Physiology, To&. Poland Stankiewicz M.', Grolleau F.~,Lapied B.~,Kadziela w.', Pelhate M.~ A studj of the literature concerning the resting potential (RP) of insect muscle Inst, of Biology and Environment Protection. N.Copernicus Univ , Torun. Poland reveals a number of apparent departures from the situation found in other (I),Lab.of Neurophysiology. EREA CNRS 120. Angers, France (2). excitable cells. The Insects. adult Colorado beetle and mealworm, and mealworm The comparative approach to investigation of the axonal and larva. chosen to this study differ much in their haemolymph ionic content (e.g neuronal mechanisms underlying rythmogenesis in invertebrates has lead Colorado beetle's haemolymph contains only 2 mmol.l-' of NaC) and so they have to an important conclusion that rythm generation is the result of complex ditferent ion~c requirements for the resting membrane potential (RMP) interactions between cellular, synaptic and network properties. The aim of maintenance and the contnbution of pumps to it. The present study examines the this study is to compare the membrane properties of insect giant axon, tlme dependence of the RP In muscles of studied insects and tries to determine the which propagates action potentials and insect neurosecretory cells called role of metabolic pumping in the genesis of tlus potentla1 using of sodium pump dorsal unpaired median (DUM) neurons involved in the modulation of idubitor - ouabain and in the case of Colorado beetle, K-H pump inhibitor - SCH skeletal and/or visceral muscles via the release of octopamine.
    [Show full text]
  • Seizures and Brain Injury in Neonatal Rats Induced by 1 S,3R-ACPD, a Metabotropic Glutamate Receptor Agonist
    The Journal of Neuroscience, October 1993, 73(10): 4445-4455 Seizures and Brain Injury in Neonatal Rats Induced by 1 S,3R-ACPD, a Metabotropic Glutamate Receptor Agonist John W. McDonald,’ Andrew S. Fix,* Joseph P. Tizzano:* and Darryle D. Schoepp’ ICNS Research Division and *Toxicology Research Laboratories, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285 The role of metabotropic excitatory amino acid receptors in receptors, which are coupled to phosphoinositide hydrolysis or seizures and brain injury was examined using the selective modulation of CAMP metabolism, have beencharacterized (Sla- metabotropic agonist 1 S,3R-ACPD [( 1 S,3R)-1 -aminocyclo- deczek et al., 1985; Nicoletti et al., 1986a; Pearce et al., 1986; pentane-1-3-dicarboxylic acid] in 7-d-old neonatal rats. Sys- Sugiyama et al., 1987; Schoepp and Johnson, 1988; Schoepp et temic administration of 1 S,3R-ACPD produced dose-depen- al., 1992b). Nonselective agonistsof metabotropic receptors in- dent convulsions (ED,, = 16 mg/kg, i.p.) that were clude glutamate, ibotenate, and quisqualate (Schoepp et al., stereoselective for the active metabotropic ACPD isomer, 1990a). Recently, more selective metabotropic agonists have since lR,BS-ACPD was less potent (ED,, = 93 mg/kg, i.p.). been developed, including (+)truns-ACPD [(f )-truns- 1-ami- 1 S,3R-ACPD-induced seizures were antagonized by sys- nocyclopentane- 1,3-dicarboxylic acid (Palmer et al., 1989; De- temic administration of dantrolene, an inhibitor of intracel- sai and Conn, 1990)]. Truns-ACPD is a racemic mixture of lular calcium mobilization, but not by the ionotropic gluta- lS,3R and lR, 3S stereoisomers.
    [Show full text]
  • Transiently Selective Activation of Phosphoinositide Turnover in Layer
    The Journal of Neuroscience, December 1995, 15(12): 7916-7928 Transiently Selective Activation of Phosphoinositide Turnover in Layer V Pyramidal Neurons After Specific mGluRs Stimulation in Rat Somatosensory Cortex During Early Postnatal Development J. A. Bevilacqua,’ C. Peter Dowries,* and Pedro R. Lowensteinl ‘Laboratory of Cellular and Molecular Neurobiology, Physiology Unit, School of Molecular and Medical Biosciences, University of Wales College of Cardiff, Cardiff CFl 3US and 2Department of Biochemistry, University of Dundee, Dundee DDl 4HN, United Kingdom Biochemical analysis of muscarinic- and metabotropic-glu- that the neocortex displays a higher susceptibility to experience- tamate receptor stimulated phosphoinositide (PI) turnover induced synaptic modification during early stages of postnatal in rat cortical preparations during the first three weeks of development (Hubel and Wiesel, 1970; Van der Loos and Wool- postnatal development indicates the existence of a tran- sey, 1973; Blakemore and Van Sluyters, 1974; Woolsey and siently increased accumulation of labeled inositol poly- Wann, 1976; Cynader and Mitchell, 1980; Fox, 1992; Schlaggar phosphates during the first postnatal week (Gonzales and et al., 1993; Fox and Zahs, 1994). Studies in the rat somatosen- Crews, 1985; Dudek et al., 1989). We now report for first sory cortex have shown the existence of a narrow period during time the visualization of those neurons responding with in- early postnatal development during which the anatomical and creased PI turnover to glutamatergic or cholinergic-recep- functional structure of the neocortex is highly modifiable in re- tor stimulation in rat somatosensory cortex during early sponse to changes in the afferent input from the peripheral sen- postnatal development utilizing a recently described meth- sory organs, and after which the cortical circuitry remains rel- od (Bevilacqua et al, 1994).
    [Show full text]
  • Activation of Metabotropic Glutamate Receptors Produces Reciprocal
    The Journal of Neuroscience, April 1993, 13(4): 1636-l 641 Activation of Metabotropic Glutamate Receptors Produces Reciprocal Regulation of lonotropic Glutamate and GABA Responses in the Nucleus of the Tractus Solitarius of the Rat Steven R. Glaum and Richard J. Miller Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, Illinois 60637 Whole-cell voltage-clamp recordings were made in thin effect was found to be independent of changes in [Ca”], and transverse slices from neurons of the dorsomeclial subdi- could be mimicked by endogenous glutamate released from af- vision of the nucleus of the tractus solitarius (NTS) of the ferent projections to the NTS by high-frequency stimulation of rat. Cells were exposed to either the ionotropic glutamate the tractus solitarius (TS). Furthermore, lS,3R-ACPD reduced receptor agonist (R,S)-a-amino+hydroxy-5methylisoxa- the glutamatergic EPSC and GABAergic IPSC evoked by low- zole-4-propionate (AMPA) or the GABA, receptor agonist frequency stimulation in the region of the TS. These effects muscimol via pressure ejection directed at the cell soma. support the view that the action of glutamate at metabotropic The metabotropic glutamate receptor agonist 1 SJR-1 -ami- receptors plays a key role in synaptic transmission from baro- nocyclopentane-1,3-dicarboxylate (1 S,3/+ACPD; 2-l 00 PM) receptor afferents (Leone and Gordon, 1989; Meeley et al., 1989; reversibly depressed muscimol-evoked currents. Converse- Drewe et al., 1990; Mifflin and Felder, 1990). ly, 1 S,BR-ACPDreversiblypotentiatedAMPA-evokedcurrents. In our previous report, we suggested that the ability of lS,3R- High-frequency stimulation of the tractus solitarius in the ACPD to inhibit synaptic transmission in the NTS might be presence of 6,7-dinitroquinoxaline-2,3-dione and o-2-amino- due to a reduction in the presynaptic release of glutamate and 5phosphonopentanoic acid also produced a reversible de- GABA.
    [Show full text]
  • Glutamate Uptake System in the Presynaptic Vesicle: Glutamic Acid Analogs As Inhibitors and Alternate Substrates*
    Neurochemical Research, VoL 18, No. 1, 1993, pp. 79-85 Glutamate Uptake System in the Presynaptic Vesicle: Glutamic Acid Analogs as Inhibitors and Alternate Substrates* Harry C. Winter ~ and Tetsufumi Ueda 2,3 (accepted March 23, 1992) A variety of naturally occurring amino acids, their isomers, and synthetic analogs were tested for their ability to inhibit uptake of [3H]glutamate into presynaptic vesicles from bovine cerebral cortex. Strongest inhibition (N < lmM) was observed for trans-l-aminocyclopentane-l,3-dicarboxylic acid (t-ACPD) and erythro-4-methyl-L-glutamic acid (MGlu), while 4-methylene-L-glutamic acid (MeGlu) was only moderately inhibitory (Ki = -3mM), indicating that the synaptic vesicle glutamate transloeator has higher affinity for trans-ACPD and MGlu than for glutamate. A few other amino acids, e.g., 4-hydroxyglutamic acid, S-carboxyethyl cysteine, and 5-fluorotryptophan, were slightly inhibitory; all L- and DL-isomers of protein amino acids and longer chain acidic amino acids were without measurable inhibition. Potassium tetrathionate and S-sulfocysteine ex- hibited strong to moderate noncompetitive or irreversible inhibition. Inhibition by t-ACPD, MGlu, or MeGlu was competitive with glutamic acid. Each of these competitive inhibitors was also taken up by the vesicle preparation in an ATP-dependent manner, as indicated by their being recovered unchanged from filtered vesicles. Similar results were obtained with reconstituted vesicles, while glutamate uptake by partially purified rat synaptosomes was inhibited only by MGIu. These results indicate that the glutamate translocator of presynaptic vesicles has stringent structural requirements distinct from those of the plasma membrane translocator and the metabotropic type of postsynaptic glutamate receptor.
    [Show full text]
  • 7Th International Congress on Amino Acids and Proteins Vienna, Austria
    Amino Acids (2001) 21: 1–90 7th International Congress on Amino Acids and Proteins Vienna, Austria August 6–10, 2001 Abstracts Co-Presidents: Steve Schaffer, Mobilel, AL, U.S.A. Michael Fountoulakis, Basel, Switzerland Gert Lubec, Vienna, Austria Contents Analysis................................................................................ 3 Biology ................................................................................ 10 Proteomics . 14 Medicine . 22 Metabolism/Nutrition . 25 Neurobiology . 35 Neuroscience . 45 Plant Amino Acids . 56 Physiology/Exercise and Sport . 59 Polyamines . 63 Synthesis . 68 Taurine ................................................................................ 74 Amino Acids Transport . 79 Addendum . 86 3 Analysis Fully automated HPLC based analysis of cysteine and related used for calculation of the degree of substitution in case of compounds in plasma using on line microdialysis as sample peptide-conjugates. The results of amino acid analysis were preparation verified by the data of ES mass spectrometry method. [This study was supported by grants from Hungarian E. Bald Research Fund (OTKA) T 030838, T025834, T032425, F034886 Department of Environmental Chemistry, University of ´Lodz´, and from the Ministry of Education (FKFP/0153/2001).] Poland Low molecular weight thiols play important roles in metabolism and homeostasis. While plasma thiols, including Free and bound cysteine in homocystinuria: assessment of metabolically related cysteine, glutathione, and homocysteine, cysteine and glutathione status are being investigated as potential indicators of health status A. Briddon1, I. P. Hargreaves1, and P. J. Lee2 and disease risk, trace levels, poor stability, and the lack of 1 structural properties necessary for the production of signals Department of Clinical Biochemistry, and compatible with common detection methods have hampered 2 Metabolic Unit, The National Hospital for Neurology and their accurate assessment. The facile oxidation of sulfhydryl Neurosurgery, London, U.K.
    [Show full text]
  • Growth Factors and Vitamin E Modify Neuronal Glutamate Toxicity DAVID SCHUBERT*T, Hideo Kimura*, and PAMELA MAHER* *The Salk Institute for Biological Studies, P.O
    Proc. Natl. Acad. Sci. USA Vol. 89, pp. 8264-8267, September 1992 Neurobiology Growth factors and vitamin E modify neuronal glutamate toxicity DAVID SCHUBERT*t, HIDEo KIMuRA*, AND PAMELA MAHER* *The Salk Institute for Biological Studies, P.O. Box 85800, San Diego, CA 92186-5800; and tWhittier Institute, 9894 Genesee Avenue, La Jolla, CA 92037 Communicated by Leslie E. Orgel, June 9, 1992 (receivedfor review May 15, 1992) ABSTRACT The sympathetic nerve cell line PC-12 is killed MATERIALS AND METHODS by glutamate in a concentration-dependent manner. Although Materials. BOAA and BMAA were obtained from Re- glycine and the deletion of magnesium weakly potentiate glu- search Biochemicals (Natick, MA). trans-l-Aminocyclopen- tamate toxicity and PC-12 cells express N-methyl-D-aspartate- tyl-1,3-dicarboxylic acid (ACPD) was from Tocris (Essex, receptor mRNA, most toxicity is mediated by means of a U.K.), and bFGF was from A. Baird (Whittier Institute). All mechanism independent of typical N-methyl-D-aspartate re- other chemicals were from Sigma. Dialyzed horse and fetal ceptors. Glutamate toxicity is, however, greatly enhanced by calf sera were from GIBCO/BRL, and Dulbecco's modified prior exposure to nerve growth factor or basic flbroblast Eagle's medium (DMEM) was made according to the original growth factor. Glutamate killing is blocked by epidermal procedure (13). In some cases MgSO4 and CaCl2 were growth factor and, to a lesser extent, by vitamin E. These deleted, and the medium was resupplemented with MgCl2 or observations show that synergistic interactions between growth CaCl2 and, in all cases, with 1 mM Na2SO4.
    [Show full text]