DOCSLIB.ORG

Polyamine Amides Are Neuroprotective in Cerebellar Granule Cell Cultures Challenged with Excitatory Amino Acids

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Polyamine Amides Are Neuroprotective in Cerebellar Granule Cell Cultures Challenged with Excitatory Amino Acids BRAIN RESEARCH ELSEVIER Brain Research 717 (1996) 135-146 Research report Polyamine amides are neuroprotective in cerebellar granule cell cultures challenged with excitatory amino acids A.C. Green a,*, K. Nakanishi b, P.N.R. Usherwood a " Department of Life Science, UniL'ersiO, of Nottingham, Universi~ Park, Nottingham NG7 2RD, UK b Department of Chemistry, Columbia University, New York, NY 10027, USA Accepted 27 December 1995 Abstract Primary cultures of rat cerebellar granule cells have been used to assess the potential neuroprotective effects of philanthotoxins and argiotoxin-636 (ArgTX-636). These polyamine amides are potent antagonists of ionotropic L-glutamate (L-Glu) receptors. In granule cells loaded with fluo-3, ArgTX-636 and philanthotoxin-343 (PhTX-343) antagonised increases of intracellular free calcium concentration ([Ca2+]i) that were stimulated by N-methyl-D-aspartate (NMDA). The antagonism was use-dependent. Antagonism by PhTX-343 was fully reversible, but recovery following antagonism by ArgTX-636 was slow and only partial during the time-course of an experiment. Neither compound inhibited K+-induced increases in [Ca 2+ ]i" In excitotoxicity studies with cerebellar granule cells, the release of lactate dehydrogenase (LDH) and morphological observations were used to assess cell death. A 20-30 min exposure to 500 /xM NMDA, 100 /xM L-Glu or 500 /zM kainate was sufficient to kill > 90% of the cells after 18-20 h. When added 5 rain prior to, and during agonist exposure, PhTX-343 and ArgTX-636 provided total neuroprotection. ArgTX-636 was about 20-30 fold more potent than PhTX-343 against NMDA, but was approximately equipotent with PhTX-343 against a kainate challenge. Neither of the toxins showed any inherent toxicity even at 400 #M and 100 /xM respectively. Some analogues of PhTX-343 are more potent, both in terms of antagonism of NMDA-stimulated increases of [Ca2+] i and neuroprotection, than PhTX-343 and ArgTX-636. Keywords: Polyamine amide toxin; Excitotoxicity; Neuroprotection; Cerebellar granule cell; Excitatory amino acid receptor 1. Introduction [4,5,13,23,27,38,39,53,62,63]. In addition to their effects on glutamate receptors, polyamine amide toxins antagonise Polyamine amide toxins are low molecular weight com- nicotinic acetylcholine receptors [7,61] and, at higher con- pounds that have been isolated from the venoms of a wide centrations, voltage-sensitive calcium channels (VSCCs) variety of spiders (e.g. argiotoxin-636; ArgTX-636), and [40,51,64,65,67]. from the Egyptian digger wasp Philanthus triangulum Sustained agonist stimulation of the ionotropic gluta- (e.g. philanthotoxin-433; PhTX-433) [10,35,69,70]. They mate receptors of excitable cells can lead to a form degen- share a similar structural design, consisting of an aromatic eration of these cells termed excitotoxicity [18,48], i.e. the chromophore, a polyamine backbone, one or more amino agonist is excitotoxic. In humans, excitotoxic cell death acid residues and a terminal amino or guanidino group [70] may contribute to the neuronal injury that follows acute (Fig. 1). These natural products contribute to the paralysing CNS insults such as ischaemia, seizures and trauma and effects of spider and wasp venoms by non-competitively may also be involved in the development of certain chronic antagonising ionotropic glutamate receptors of prey such neurodegenerative diseases [18,48]. Data from in vitro as insects [20,42]. They are also potent, non-competitive models suggest that the entry of Ca 2+ plays a pivotal role antagonists of ionotropic glutamate receptors of mam- in the initiation of a cascade of changes that leads eventu- malian central nervous systems (CNS), where both N- ally to cell death [17,19,25,28,29,60]. Prevention of Ca 2+ methyl-D-aspartate (NMDA) and non-NMDA L-glutamate entry, particularly through channels gated by NMDA re- (L-G lu) receptors are antagonised ceptors [57,68] and VSCCs [6,71] may be an efficacious neuroprotective strategy, which might be achieved using either competitive or non-competitive antagonists of these * Corresponding author. Fax: (44) (115) 951-3251. signalling proteins. However, some subtypes of non- 0006-8993/96/$15.00 © 1996 Elsevier Science B.V. All rights reserved PI1 S0006- 8993(96)00042-X 136 A.C. Green et al. / Brain Research 717 (1996) 135-146 NMDA receptor types are also permeable to Ca 2+ [12]. 2. Materials and methods For this reason polyamine amides might be ideally suited as neuroprotectants because they antagonise both NMDA and non-NMDA classes of L-Glu receptor as well as 2.1. Granule cell culture VSCCs [40,65,67,70]. In this study, polyamine amide- mediated antagonism of NMDA receptors and VSCCs in primary cultures of rat cerebellar granule cells has been Primary cultures of cerebellar granule cells were grown examined by monitoring changes of intracellular free Ca 2+ by a modification of published procedures [49]. The cere- ([ Ca2+ ]i)- In addition, these cells undergo a marked excito- bella from 7-8 day old rats (Wistar) were pooled and toxic degeneration in response to challenge with NMDA, finely chopped. The slices were collected in a modified L-Glu or kainate [41,46,47] thus allowing polyamine Kreb's medium supplemented with trypsin and DNAse amide-mediated neuroprotection to be investigated quanti- (0.25% and 0.01% w/v, respectively). After a 15 min tatively. incubation at 25°C, the trypsin solution was removed and A -Trptophan- ~ NAI'~NH3o + -Gycine (-Trp-) ~ H (-Gly) o I N~NH3 + -Lysine tt ~l~i3 (-Lys) Diiodo- o~ ~H (Iz -) i O NIt 2 N~N.~2 -Arginine . ~i 3 I4 (-Arg) O Hexadiene- ~'v +NH2,.~-..~~'~" -343- O H2 H H 2 H 2 + Ph- N~,~N~N~.I~N~ -3343- CY' H2 O C 7- ............) O Cm- B ArgTX-636 OH h O 0 ,,NH2 N + + + 1~ q X /H H2 H2 H -~ H HO~f"~s~ u "~CONIt,2 21"13 C .~.f.on C4 -Tyr-Asn-533-Arg H O ,NH2 N + + .~+ Fig. 1. Structures of the polyamine amides used in these studies. A: structure of the wasp toxin PhTX-433, and substitutions. B: structure of the spider toxin ArgTX-636. C: structure of a hybrid philanthotoxin-argiotoxin molecule C4-Tyr-Asn-533-Arg. Note that the nmnbers in PhTX-433 and analogues and in the hybrid molecule refer to the number of methylenes between the amino groups. In ArgTX-636 they represent the molecular weight of the toxin. A.C. Green et al./ Brain Research 717 (1996) 135-146 137 replaced with culture medium (Minimum Essential Medium reproducible responses could be routinely recorded from (MEM) with Earle's salts, supplemented with 10% foetal successive stimulations of the same group of cells (see calf serum, 2 mM glutamine, 5 /xg/ml insulin, 3.5 g/1 Results). Calibration of these data using ionomycin and D-glucose, KC1 to a final concentration of 25 raM, peni- Mn 2+ quenching proved unreliable, with fuorescence in- cillin 10 IU/ml and streptomycin 10 /xg/ml) supple- creases in the presence of ionomycin/Ca 2+ being unstable mented with 0.01% DNAse. The tissue was then dissoci- and not well-maintained. Consequently, these results have ated by gentle trituration through a graded series of fire- been expressed as a change in the fluorescence intensity polished Pasteur pipettes. The dissociated cells were col- relative to baseline (i.e. AF/F where AF is the change in lected by a brief centrifugation (1000 × g max 5 min) and fluo-3 fluorescence intensity and F is the baseline fluores- resuspended in fresh culture medium. The cell suspension cence measured after subtraction of the background signal was passed through a 77 ~m steel mesh to remove undis- recorded following lysis of cells by Triton-X100). Fluo-3 sociated tissue and cell clumps and diluted to ~ 1.5 × 10 6 was used in these studies because of constraints imposed cells/ml. Cells were plated in 24-well plates (0.5 ml/well) by the available single wavelength microfluorimetry equip- coated with poly-D-lysine for toxicity studies or on to 22 ment. Subsequently however we have obtained preliminary mm square coverslips (No. 1) coated with poly-D-lysine data from granule cells loaded with the ratiometric Ca R+ and placed in 35 mm Petri dishes for Ca R+ studies. The sensitive dye fura-2. Measurements of [Ca 2+ ]i obtained cultures were incubated at 37°C in humidified 95% air/5% with a duel wavelength fluorescence imaging system and CO 2. After 18-24 h, the culture medium was replaced IonVision software (Image processing and Vision Com- with fresh medium containing 10 /xM cytosine-/3-D- pany Ltd.) have been fully supportive of the data presented arabinofuranoside to prevent the replication of non-neuro- in this report and will be the subject of future publications. nal cells. The medium was not changed again during the culture period. Cells were used after 9-14 days in vitro for 2.3. Toxicity studies Ca R+ studies and at 12-14 days for toxicity studies. Acute exposures to excitotoxic agents (500/xM NMDA, 2.2. Calcium studies 100 /xM L-Glu and 500 /xM kainate) were conducted at 22-25°C in HEPES-buffered Locke's solution. For expo- Measurements of changes of [Ca2+] i were made using sures to NMDA and L-Glu, Mg z+ was omitted. The the cae+-sensitive fluorescent dye fluo-3 essentially as cultures were washed twice in this solution before the test described by Richardson et al. [59]. The dye was intro- agents were added. Antagonists, when present, were added duced into the granule cells by a 30-40 min incubation 5 min prior to an agonist and were present throughout the with 2.5 /xM fluo-3 AM in serum-free culture medium period of exposure to agonist.
Load more

Recommended publications
  • Regulation of Extracellular Arginine Levels in the Hippocampus in Vivo
    Regulation of Extracellular Arginine Levels in the Hippocampus In Vivo by Joanne Watts B.Sc. (Hons) r Thesis submitted for the degree of Doctor of Philosophy in the Faculty of Science, University of London The School of Pharmacy University of London ProQuest Number: 10105113 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest 10105113 Published by ProQuest LLC(2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Abstract Nitric oxide (NO) has emerged as an ubiquitous signaling molecule in the central nervous system (CNS). NO is synthesised from molecular oxygen and the amino acid L-arginine (L- ARG) by the enzyme NO synthase (NOS), and the availability of L-ARG has been implicated as the limiting factor for NOS activity. Previous studies have indicated that L- ARG is localised in astrocytes in vitro and that the in vitro activation of non-N-methyl-D- aspartate (NMDA) receptors, as well as the presence of peroxynitrite (ONOO ), led to the release of L-ARG. Microdialysis was therefore used in this study to investigate whether this held true in vivo.
    [Show full text]
  • Glutamate Receptor Antagonism: Neurotoxicity, Anti-Akinetic Effects, and Psychosis
    J Neural Transm (1991) [Suppl] 34: 203-210 © by Springer-Verlag 1991 Glutamate receptor antagonism: neurotoxicity, anti-akinetic effects, and psychosis P. Riederer1, K. W. Lange1, J. Kornhuber1, and K. Jellinger2 'Clinical Neurochemistry, Department of Psychiatry, University of Wiirzburg, Federal Republic of Germany 2Ludwig Boltzmann Institute of Clinical Neurobiology, Lainz Hospital, Vienna, Austria Summary. There is evidence to suggest that glutamate and other excitatory amino acids play an important role in the regulation of neuronal excitation. Glutamate receptor stimulation leads to a non-physiological increase of intra• cellular free Ca2+. Disturbed Ca2+ homeostasis and subsequent radical formation may be decisive factors in the pathogenesis of neurodegenerative diseases. Decreased glutamatergic activity appears to contribute to paranoid hallucinatory psychosis in schizophrenia and pharmacotoxic psychosis in Parkinson's disease. It has been suggested that a loss of glutamatergic function causes dopaminergic over-activity. Imbalances of glutamatergic and dopaminer• gic systems in different brain regions may result in anti-akinetic effects or the occurrence of psychosis. The simplified hypothesis of a glutamatergic- dopaminergic (im)-balancc may lead to a better understanding of motor behaviour and psychosis. Introduction It is only recently that excitatory amino acid receptors have been dis• covered. Through the use of selective agonists and antagonists it has become evident that these receptors consist of different subtypes (for review see Watkins et al., 1990). At present the most useful classification provides the following excitatory amino acid receptor subtypes: N-methyl-D-aspartate (NMDA) receptors, kainate receptors, quisqualate receptors or a-amino-3- hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, metabotropic receptors and L-aminophosphonobutyrate (L-AP4) receptors.
    [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]
  • Excitotoxic Death of Retinal Neuronsin Vivooccurs Via a Non-Cell
    5536 • The Journal of Neuroscience, April 29, 2009 • 29(17):5536–5545 Cellular/Molecular Excitotoxic Death of Retinal Neurons In Vivo Occurs via a Non-Cell-Autonomous Mechanism Fre´de´ric Lebrun-Julien,1* Laure Duplan,1* Vincent Pernet,1 Ingrid Osswald,2 Przemyslaw Sapieha,1 Philippe Bourgeois,1 Kathleen Dickson,3 Derek Bowie,2 Philip A. Barker,3# and Adriana Di Polo1# 1Department of Pathology and Cell Biology and Groupe de Recherche sur le Syste`me Nerveux Central, Universite´ de Montre´al, Montreal, Quebec H3T 1J4, Canada, 2Department of Pharmacology and Therapeutics, and 3Centre for Neuronal Survival, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada The central hypothesis of excitotoxicity is that excessive stimulation of neuronal NMDA-sensitive glutamate receptors is harmful to neurons and contributes to a variety of neurological disorders. Glial cells have been proposed to participate in excitotoxic neuronal loss, but their precise role is defined poorly. In this in vivo study, we show that NMDA induces profound nuclear factor ␬B (NF-␬B) activation in Mu¨ller glia but not in retinal neurons. Intriguingly, NMDA-induced death of retinal neurons is effectively blocked by inhibitors of NF-␬B activity. We demonstrate that tumor necrosis factor ␣ (TNF␣) protein produced in Mu¨ller glial cells via an NMDA-induced NF-␬B-dependent pathway plays a crucial role in excitotoxic loss of retinal neurons. This cell loss occurs mainly through a TNF␣- dependent increase in Ca 2ϩ-permeable AMPA receptors on susceptible neurons. Thus, our data reveal a novel non-cell-autonomous mechanism by which glial cells can profoundly exacerbate neuronal death following excitotoxic injury.
    [Show full text]
  • Information to Users
    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. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6 " x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms international A Bell & Howell Information Company 300 North Zeeb Road. Ann Arbor. Ml 48106-1346 USA 313/761-4700 800/521-0600 Order Number 9211140 P a rt 1 . Design, synthesis, and structure-activity studies of molecules with activity at non-NMDA glutamate receptors: Hydroxyphenylalanines, quinoxalinediones and related molecules.
    [Show full text]
  • Intracellular NASPM Allows an Unambiguous Functional Measure Of
    bioRxiv preprint doi: https://doi.org/10.1101/2021.02.18.431828; this version posted February 19, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1 Intracellular NASPM allows an unambiguous functional measure of 2 GluA2-lacking calcium-permeable AMPA receptor prevalence 3 Ian D. Coombs, Cécile Bats, Craig A. Sexton, Stuart G. Cull-Candy* and 4 Mark Farrant* 5 Department of Neuroscience, Physiology, and Pharmacology, University College 6 London, London WC1E 6BT, United Kingdom 7 *Authors for correspondence: 8 Stuart G. Cull-Candy ([email protected]), Mark Farrant ([email protected]). 9 Acknowledgements: 10 This work was supported by an MRC Programme Grant (MR/T002506/1) to MF and 11 SGCC. 1 bioRxiv preprint doi: https://doi.org/10.1101/2021.02.18.431828; this version posted February 19, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 12 Abstract 13 Calcium-permeable AMPA-type glutamate receptors (CP-AMPARs) contribute to 14 many forms of synaptic plasticity and pathology. They can be distinguished from 15 GluA2-containing calcium-impermeable AMPARs by the inward rectification of their 16 currents, which reflects voltage-dependent block by intracellular spermine. However, 17 the efficacy of this weakly permeant blocker is differentially altered by the presence of 18 AMPAR auxiliary subunits – including transmembrane AMPAR regulatory proteins, 19 cornichons and GSG1L – that are widely expressed in neurons and glia.
    [Show full text]
  • Strategies for Neuroprotection and Intraocular Pressure Modulation in Experimental Models of Glaucoma
    Strategies for Neuroprotection and Intraocular Pressure Modulation in Experimental Models of Glaucoma by Elizabeth Anne Cairns Submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Dalhousie University Halifax, Nova Scotia December 2017 © Copyright by Elizabeth Anne Cairns, 2017 This thesis is dedicated in the memory of three people of whom were perhaps my biggest supporters in pursuing a PhD, and of whom would have been so excited to read the final product Prof. Owen C. Sharkey (1922 – 2014) Dr. Thompson T. Wright (1919 – 2016) Marlene A. Cairns (1958 – 2017) ii TABLE OF CONTENTS List of Tables ............................................................................................................................ vii List of Figures ......................................................................................................................... viii Abstract……. ............................................................................................................................... xi List of Abbreviations Used .................................................................................................. xii Acknowledgments ................................................................................................................ xvi Chapter 1: Introduction ....................................................................................................... 1 1.1 The Eye ........................................................................................................................................
    [Show full text]
  • Permeable AMPA Receptors at Perisynaptic Sites by Glur1-S845 Phosphorylation
    Stabilization of Ca2؉-permeable AMPA receptors at perisynaptic sites by GluR1-S845 phosphorylation Kaiwen Hea,b, Lihua Songa, Laurel W. Cummingsa, Jonathan Goldmanb, Richard L. Huganirc,1, and Hey-Kyoung Leea,b,1 aDepartment of Biology, College of Chemical and Life Sciences and bNeuroscience and Cognitive Science (NACS) Program, University of Maryland, College Park, MD 20742; and cSolomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins School of Medicine, Baltimore, MD 21210 Contributed by Richard L. Huganir, September 25, 2009 (sent for review July 23, 2009) AMPA receptor (AMPAR) channel properties and function are regulates perisynaptic AMPAR subunit composition by stabi- regulated by its subunit composition and phosphorylation. Cer- lizing GluR1 homomers, and that LTD is associated with the .tain types of neural activity can recruit Ca2؉-permeable (CP) removal of CP-AMPARs AMPARs, such as GluR1 homomers, to synapses likely via lateral diffusion from extrasynaptic sites. Here we show that GluR1- Results S845 phosphorylation can alter the subunit composition of CP-AMPARs at Perisynaptic Sites of Schaffer Collateral Inputs to CA1. perisynaptic AMPARs by providing stability to GluR1 homomers. Using the property that CP-AMPARs are sensitive to applica- Using mice specifically lacking phosphorylation of the GluR1- tion of an exogenous polyamine philanthotoxin-433 (PhTX), we S845 site (GluR1-S845A mutants), we demonstrate that this site tested the presence of these receptors at Schaffer collateral is necessary for maintaining CP-AMPARs. Specifically, in the synapses on CA1 neurons. Similar to previous reports (20, 21), GluR1-S845A mutants, CP-AMPARs were absent from perisyn- bath application of PhTX (3 ␮M) did not alter AMPAR aptic locations mainly due to lysosomal degradation.
    [Show full text]
  • 2869.Full-Text.Pdf
    The Journal of Neuroscience, May 1, 1996, 76(9):2869-2880 Structure and Pharmacological Properties of a Molluscan Glutamate-Gated Cation Channel and its Likely Role in Feeding Behavior Thor&en Stiihmer,’ Muriel Amar, 192 Robert J. Harvey,’ Isabel Bermudez,* Jan van Minnen,3 and Mark G. Darlisonl llnstitut fijr Zellbiochemie und Klinische Neurobiologie, Universittits-Krankenhaus Eppendorf, Universits t Hamburg, 20246 Hamburg, Germany, 2School of Biological and Molecular Sciences, Oxford Brookes University, Headington, Oxford OX3 OBP, United Kingdom, and 3Department of Organismic Zoology, Vr#e Universiteit, 108 7 HV Amsterdam, The Netherlands We describe the isolation of a molluscan (Lymnaea stagnalis) shown that the agonist-induced current is carried entirely by full-length complementary DNA that encodes a mature sodium and potassium ions. In situ hybridization has revealed polypeptide (which we have named Lym-eGluR2) with a pre- that the Lym-eGluR2 transcript is present in all 11 ganglia of the dicted molecular weight of 10.5 kDa that exhibits 44-48% Lymnaea CNS, including the 4-cluster motorneurons within the identity to the mammalian kainate-selective glutamate receptor paired buccal ganglia. The pharmacological properties and GluR5, GIuR6, and GluR7 subunits. Injection of in vitro- deduced location of Lym-eGluR2 are entirely consistent with it transcribed RNA from this clone into Xenopus laevis oocytes being (a component 09 the receptor, which has been identified results in the robust expression of homo-oligomeric cation previously on buccal motorneurons, that mediates the excita- channels that can be gated by L-glutamate (E& = 1.2 2 tory effects of glutamate released from neurons within the 0.3 PM) and several other glutamate receptor agonists; rank order feeding central pattern generator.
    [Show full text]
  • Synapse-Specific Compartmentalization of Signaling Cascades for Ltp Induction in Ca3 Interneurons
    Neuroscience 290 (2015) 332–345 SYNAPSE-SPECIFIC COMPARTMENTALIZATION OF SIGNALING CASCADES FOR LTP INDUCTION IN CA3 INTERNEURONS E. J. GALVA´N, a* T. PE´REZ-ROSELLO, b protein kinase C (PKC). Specifically, LTP at RC and MF G. GO´MEZ-LIRA, a E. LARA, a R. GUTIE´RREZ a AND synapses on the same SR/LM interneuron was blocked by c G. BARRIONUEVO postsynaptic injections of chelerythrine (10 lM). These data a Departamento de Farmacobiologı´a, Cinvestav Sede Sur, indicate that both forms of LTP share a common Me´xico City, Mexico mechanism involving PKC-dependent signaling modulation. Ó 2015 IBRO. Published by Elsevier Ltd. All rights reserved. b Department of Physiology, Northwestern University, Chicago, IL, USA c Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA Key words: recurrent commissural LTP and LTD, calcium impermeable AMPARs, CaMKII; PKA; PKC, CA3 interneurons, Abstract—Inhibitory interneurons with somata in strata rad- feed-forward inhibition. iatum and lacunosum-moleculare (SR/L-M) of hippocampal area CA3 receive excitatory input from pyramidal cells via the recurrent collaterals (RCs), and the dentate gyrus gran- INTRODUCTION ule cells via the mossy fibers (MFs). Here we demonstrate that Hebbian long-term potentiation (LTP) at RC synapses The majority of excitatory synapses in hippocampal area on SR/L-M interneurons requires the concomitant activation CA3 originate from the extensive recurrent collateral of calcium-impermeable AMPARs (CI-AMPARs) and (RC) axons of pyramidal cells (Amaral and Witter, 1989; N-methyl-D-aspartate receptors (NMDARs). RC LTP was pre- Ishizuka et al., 1990). The RC circuitry underlies many vented by voltage clamping the postsynaptic cell during autoassociative network models that simulate pattern high-frequency stimulation (HFS; 3 trains of 100 pulses completion, i.e.
    [Show full text]
  • Role of Reactive Gliosis and Neuroinflammation in Experimental Glaucoma
    Université de Montréal Role of Reactive Gliosis and Neuroinflammation in Experimental Glaucoma Par JORGE LUIS CUEVA VARGAS Département de pathologie et biologie cellulaire Faculté de Médecine Thèse présentée à la Faculté des études supérieures en vue de l’obtention du grade de Philosophie Doctor (Ph.D.) en pathologie et biologie cellulaire June 2015 © Jorge Luis Cueva Vargas, 2015 Université de Montréal Faculté des études supérieures et postdoctorales Cette thèse de doctorat intitulée : «Role of reactive gliosis and neuroinflammation in experimental glaucoma » Présentée par: JORGE LUIS CUEVA VARGAS a été évaluée par un jury composé de personnes suivantes: Hélène Girouard, PhD président-rapporteur Adriand Di Polo, Ph.D directrice de recherche Nathalie Arbour, PhD Membre du jury Marie-Ève Tremblay, PhD examinateur externe Graziella Di Cristo, PhD représentant du doyen de la FES ii RÉSUMÉ Le glaucome est la principale cause de cécité irréversible dans le monde. Chez les patients atteints de cette pathologie, la perte de la vue résulte de la mort sélective des cellules ganglionnaires (CGR) de la rétine ainsi que de la dégénérescence axonale. La pression intraoculaire élevée est considérée le facteur de risque majeur pour le développement de cette maladie. Les thérapies actuelles emploient des traitements pharmacologiques et/ou chirurgicaux pour diminuer la pression oculaire. Néanmoins, la perte du champ visuel continue à progresser, impliquant des mécanismes indépendants de la pression intraoculaire dans la progression de la maladie. Il a été récemment démontré que des facteurs neuroinflammatoires pourraient être impliqués dans le développement du glaucome. Cette réponse est caractérisée par une régulation positive des cytokines pro- inflammatoires, en particulier du facteur de nécrose tumorale alpha (TNFα).
    [Show full text]
  • Synthesis and Pharmacological Activity of Philanthotoxin-343 Analogs: Antagonists of Ionotropic Glutamate Receptors
    Tetrahedron, Vol. 53, No. 37, pp. 12391-12404, 1997 Pergamon © 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0040-4020/97 $17.00 + 0.00 PII: S0040-4020(97)00801-6 Synthesis and Pharmacological Activity of Philanthotoxin-343 Analogs: Antagonists of Ionotropic Glutamate Receptors Danwen Huang, Hong Jiang, Koji Nakanishi* Department of Chemistry, ColumbiaUniversity, New York, New York 10027 P. N. R. Usherwood Department of Life Science, University of Nottingham, Nottingham NG 7 2RD, UK Abstract: The synthesis of two classes of Philanthotoxin-343 analogs is described. Quantitative information on the antagonism of quisqualate-sensitive ionotropic glutamate receptors of insect muscle by these compounds is presented. © 1997 Elsevier Science Ltd. INTRODUCTION L-Glutamate, a major neurotransmitter in vertebrates 1,2 and invertebrates3, interacts at neuronal and nerve-muscle synapses with postjunctional proteins, the glutamate receptors. 4 The latter group has attracted much attention because in the mammalian brain they are implicated in several higher neural functions such as memory and learning as well as degenerative brain diseases and ischemic damage 5,6. Electrophysiological, pharmacological and molecular biological studies have resulted in the division of glutamate receptors into two groups, the ionotropic receptors that gate integral ion channels and the metabotropic receptors that are coupled to G-proteins. 4 Mammalian ionotropic glutamate receptors are divided into two classes according to their selective agonists, i.e. the N-methyl-D-aspartate receptors (NMDAR, NR1 and NR2A-D) and the ~-amino-3- hydroxy-5-methyl-4-isoxazole-propionate(AMPA) / kainate receptors (non-NMDAR, Glul-6). 1 Invertebrate ionotropic glutamate receptors are of four subtypes: (i) quisqualate receptors (qGluR) that gate cation channels; (it) ibotenate receptors that gate anion channels; (iii) kainate receptors; and (iv) NMDA receptors.
    [Show full text]