DOCSLIB.ORG

Molecular Determinants of Picrotoxin Inhibition of 5-Hydroxytryptamine Type 3 Receptors

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Molecular Determinants of Picrotoxin Inhibition of 5-Hydroxytryptamine Type 3 Receptors 0022-3565/05/3141-320–328$20.00 THE JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS Vol. 314, No. 1 Copyright © 2005 by The American Society for Pharmacology and Experimental Therapeutics 80325/3037370 JPET 314:320–328, 2005 Printed in U.S.A. Molecular Determinants of Picrotoxin Inhibition of 5-Hydroxytryptamine Type 3 Receptors Paromita Das and Glenn H. Dillon Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas Received November 6, 2004; accepted March 25, 2005 ABSTRACT Downloaded from Previously, we reported that the GABAA receptor antagonist ceptors, and also conferred distinct gating kinetics. The equiv- Ј picrotoxin also antagonizes serotonin (5-HT)3 receptors and alent mutation in the 3B subunit (i.e., 7 valine to threonine) had that its effects are subunit-dependent. Here, we sought to no impact on PTX sensitivity in 5-HT3A/3B receptors. Interest- 3 3 identify amino acids involved in picrotoxin inhibition of 5-HT3 ingly, [ H]ethynylbicycloorthobenzoate ([ H]EBOB), a high-af- receptors. Mutation of serine to alanine at the transmembrane finity ligand to the convulsant site in GABAA receptors, did not Ј domain 2 (TM2) 2 position did not affect picrotoxin (PTX) exhibit specific binding in 5-HT3A receptors. The structurally sensitivity in murine 5-HT3A receptors. However, mutation of related compound, tert-butylbicyclophosphorothionate (TBPS), jpet.aspetjournals.org Ј the 6 TM2 threonine to phenylalanine dramatically reduced which potently inhibits GABAA receptors, did not inhibit 5-HT3 PTX sensitivity. Mutation of 6Ј asparagine to threonine in the currents. Our results indicate that the TM2 6Ј residue is a 5-HT3B subunit enhanced PTX sensitivity in heteromeric common determinant of PTX inhibition of both 5-HT3 and Ј 5-HT3A/3B receptors. Introduction of serine (native to the human GABAA receptors and demonstrate a role of the 7 residue in 3B subunit) at the 6Ј position also increased PTX sensitivity, PTX inhibition. However, lack of effects of EBOB and TBPS in Ј suggesting a species-specific effect. Mutation of the 7 leucine 5-HT3A receptors suggests that the functional domains in the to threonine in 5-HT3A receptors increased PTX sensitivity two receptors are not equivalent and underscores the complex- at ASPET Journals on January 18, 2020 roughly 10-fold, comparable with that observed in GABAA re- ity of PTX modulation of LGICs. The 5-hydroxytryptamine type 3 (5-HT3) receptor is a coexpression of 5-HT3B with the 5-HT3A subunit results in a member of the cys-loop superfamily of ligand-gated ion chan- heteromeric receptor with distinct biophysical properties nels (LGICs) that includes nicotinic acetylcholine receptors, (Davies et al., 1999). Recently, three additional putative GABA , GABA , glycine receptors, and invertebrate gluta- A c 5-HT3 subunits, 5-HT3C, 3D, and 3E have been cloned (Niesler mate-gated chloride channels (Reeves et al., 2001; Karlin, et al., 2003). The pharmacological and functional properties 2002). 5-HT receptor antagonists are useful as antiemetics 3 of these novel 5-HT3-like subunits are currently unknown. in chemotherapy-induced emesis and in irritable bowel syn- Like other members of this superfamily, the 5-HT3 recep- drome. They also may have utility in treatment of neuropsy- tor is pentameric in nature, with the five subunits surround- chiatric diseases such as anxiety and drug dependence and in ing a central ion channel (Boess et al., 1995). The receptor management of pain (Costall and Naylor, 2004). shares structural features common to LGICs, such as a large The 5-HT subunit was identified initially and shown to 3A extracellular N-terminal region, four transmembrane (TM) form functional homomeric receptors (Maricq et al., 1991). A domains (TM1–TM4), and an intracellular loop between TM3 second subunit (5-HT ) was subsequently cloned and char- 3B and TM4. Evidence suggests that the agonist binding site is acterized (Davies et al., 1999). The 5-HT3B subunit is inca- pable of forming functional homomeric cell surface receptors located in the N-terminal region, whereas TM2 forms the because it is retained in the endoplasmic reticulum in the pore (Akabas et al., 1994; Ortells and Lunt, 1995; Brejc et al., absence of the 3A subunit (Boyd et al., 2003). However, 2001). The plant-derived alkaloid picrotoxin was originally shown This work was supported by National Institutes of Health Grant ES07904 to be a noncompetitive antagonist of GABAA receptors (to G.H.D.). (Takeuchi and Takeuchi, 1969). It was subsequently demon- Article, publication date, and citation information can be found at strated that picrotoxin inhibits other anion-selective ligand- http://jpet.aspetjournals.org. doi:10.1124/jpet.104.080325. gated anion channels, including glycine and GABAC recep- ABBREVIATIONS: 5-HT, 5-hydroxytryptamine; LGIC, ligand-gated ion channel; TM, transmembrane; PTX, picrotoxin; m-CPBG, meta-chloro- phenylbiguanide; EBOB, ethynylbicycloorthobenzoate; TBPS, tert-butylbicyclophosphorothionate; [3H]GR65630, [3H]3-(5-methyl-1H-imidazol-4- yl)-1-methyl-1H-indol-3-yl)-1-propanone. 320 Picrotoxin Blocks 5-HT3 Receptors at Transmembrane Domain 2 321 tors (Pribilla et al., 1992; Wang et al., 1995) and glutamate- N6ЈT,V7ЈT), mutagenic primers were designed using B-N6ЈTasthe gated ClϪ channels (Etter et al., 1999). Recently, we have template DNA. All mutations were confirmed by DNA sequencing (Texas Tech University, Lubbock, TX). Wild-type and mutant recep- shown that PTX also inhibits the cation-selective 5-HT3A receptors in a noncompetitive, use-facilitated manner (Das et tors were transfected in HEK-293 cells using the modified calcium al., 2003). Additionally, the interaction of PTX with the phosphate transfection method (Chen and Okayama, 1987). For each ␮ 5-HT receptor is subunit-dependent. Coexpression of the transfection, approximately 4 to 10 g of DNA was used. For cotrans- 3 fection of receptor subunits, a 1:1 ratio of respective cDNA was used 5-HT subunit with the 5-HT subunit results in a sub- 3B 3A (unless otherwise stated). Cells were washed twice and were used for stantial decrease in PTX sensitivity, making PTX the only recording 12 to 48 h after transfection. antagonist that displays notable selectivity between homo- Radioligand Binding Assays. Saturation experiments were car- meric and heteromeric 5-HT3 receptors (Das and Dillon, ried out using membranes harvested from a stable cell line express- 2003). ing the 5-HT3A receptor. Briefly, HEK-293 cells stably expressing the In the present report, we sought to identify the molecular 5-HT3A receptor were grown as described previously (Das et al., determinants of PTX inhibition of 5-HT3 receptors. Although 2003) and harvested using the method described by Yagle et al. the precise location of PTX binding in anion-selective chan- (2003). Membranes were suspended in sodium phosphate buffer (200 ⅐ nels is unknown, evidence indicates it acts at the cytoplasmic mM NaCl and 50 mM NaH2PO4 2H2O, pH 7.4) such that the final aspect of the highly conserved TM2 domain (Fig. 1) (Ffrench- concentration was approximately 2 mg/ml and stored at Ϫ80°C. Constant et al., 1993; Gurley et al., 1995; Buhr et al., 2001; Initial saturation experiments using tissue harvested from the sta- ble cell line suggested high Bmax values. Thus, relatively low amount Shan et al., 2001; Dibas et al., 2002). Because the mechanism Downloaded from of protein was used for subsequent assays. For experiments using of block by PTX appears comparable in anion-selective and [3H]GR65630, tissue was thawed and diluted in sodium phosphate 5-HT3 receptors and because the TM2 domain of the 5-HT3 buffer, and a fixed concentration of protein (5–12 ␮g) was added to receptor shares notable homology with the GABAA receptor varying concentrations of the radioligand (0.8–20 nM). Nonspecific (Fig. 1), we focused on this region as the probable site of binding was defined using 10 ␮M m-CPBG. Final volumes for all action of PTX in 5-HT3 receptors. In the present study, we assays were 250 ␮l. Samples were incubated in borosilicate glass Ј Ј demonstrate that the 6 and 7 positions of TM2 are major tubes for 30 min at 37°C, reaction was terminated by addition of jpet.aspetjournals.org determinants of PTX sensitivity in the 5-HT3 receptor. ice-cold sodium phosphate buffer, and bound ligand was separated from free using a Millipore 12-well manifold vacuum filtration sys- tem (Millipore Corporation, Billerica, MA). Saturation experiments Materials and Methods using [3H]EBOB were carried out using a similar protocol as de- Materials. 5-HT, m-CPBG, and PTX were purchased from Sigma- scribed above. In this case, nonspecific binding was defined using 100 ␮ Aldrich (St. Louis, MO). [3H]GR65630 (85.5 Ci/mmol) and [3H]EBOB M PTX, and samples were incubated at room temperature for 90 (38 Ci/mmol) were purchased from PerkinElmer Life and Analytical min. All assays were performed in triplicate, and a minimum of three Sciences (Boston, MA). 5-HT and m-CPBG stocks were made in experiments was carried out for each saturation assay. Radioactivity at ASPET Journals on January 18, 2020 was measured using liquid scintillation (PerkinElmer Life and An- ultrapure H2O. PTX was made in dimethylsulfoxide and diluted in extracellular saline solution so that the final dimethylsulfoxide con- alytical Sciences). Data analysis was performed using Origin 5.0 centration (v/v) was Ͻ0.3%. Primers for mutations were synthesized (Yagle et al., 2003). at IDT, Inc. (Coralville, IA). Electrophysiological Recordings. Whole-cell recordings were Cell Culture, Site-Directed Mutagenesis, and Expression of performed as described previously (Bell-Horner et al., 2000). Patch pipettes were pulled from thin-walled borosilicate glass using a 5-HT3 Receptor cDNA. Mouse 5-HT3A (GenBank accession no. horizontal micropipette puller (P-87/PC; Sutter Instrument Com- S41757) and 5-HT3B subunits (AAF73284, kindly provided by Dr.
Load more

Recommended publications
  • Downloaded from the National Database for Autism Research (NDAR)
    International Journal of Molecular Sciences Article Phenotypic Subtyping and Re-Analysis of Existing Methylation Data from Autistic Probands in Simplex Families Reveal ASD Subtype-Associated Differentially Methylated Genes and Biological Functions Elizabeth C. Lee y and Valerie W. Hu * Department of Biochemistry and Molecular Medicine, The George Washington University, School of Medicine and Health Sciences, Washington, DC 20037, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-202-994-8431 Current address: W. Harry Feinstone Department of Molecular Microbiology and Immunology, y Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA. Received: 25 August 2020; Accepted: 17 September 2020; Published: 19 September 2020 Abstract: Autism spectrum disorder (ASD) describes a group of neurodevelopmental disorders with core deficits in social communication and manifestation of restricted, repetitive, and stereotyped behaviors. Despite the core symptomatology, ASD is extremely heterogeneous with respect to the severity of symptoms and behaviors. This heterogeneity presents an inherent challenge to all large-scale genome-wide omics analyses. In the present study, we address this heterogeneity by stratifying ASD probands from simplex families according to the severity of behavioral scores on the Autism Diagnostic Interview-Revised diagnostic instrument, followed by re-analysis of existing DNA methylation data from individuals in three ASD subphenotypes in comparison to that of their respective unaffected siblings. We demonstrate that subphenotyping of cases enables the identification of over 1.6 times the number of statistically significant differentially methylated regions (DMR) and DMR-associated genes (DAGs) between cases and controls, compared to that identified when all cases are combined. Our analyses also reveal ASD-related neurological functions and comorbidities that are enriched among DAGs in each phenotypic subgroup but not in the combined case group.
    [Show full text]
  • Molecular Dissection of G-Protein Coupled Receptor Signaling and Oligomerization
    MOLECULAR DISSECTION OF G-PROTEIN COUPLED RECEPTOR SIGNALING AND OLIGOMERIZATION BY MICHAEL RIZZO A Dissertation Submitted to the Graduate Faculty of WAKE FOREST UNIVERSITY GRADUATE SCHOOL OF ARTS AND SCIENCES in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Biology December, 2019 Winston-Salem, North Carolina Approved By: Erik C. Johnson, Ph.D. Advisor Wayne E. Pratt, Ph.D. Chair Pat C. Lord, Ph.D. Gloria K. Muday, Ph.D. Ke Zhang, Ph.D. ACKNOWLEDGEMENTS I would first like to thank my advisor, Dr. Erik Johnson, for his support, expertise, and leadership during my time in his lab. Without him, the work herein would not be possible. I would also like to thank the members of my committee, Dr. Gloria Muday, Dr. Ke Zhang, Dr. Wayne Pratt, and Dr. Pat Lord, for their guidance and advice that helped improve the quality of the research presented here. I would also like to thank members of the Johnson lab, both past and present, for being valuable colleagues and friends. I would especially like to thank Dr. Jason Braco, Dr. Jon Fisher, Dr. Jake Saunders, and Becky Perry, all of whom spent a great deal of time offering me advice, proofreading grants and manuscripts, and overall supporting me through the ups and downs of the research process. Finally, I would like to thank my family, both for instilling in me a passion for knowledge and education, and for their continued support. In particular, I would like to thank my wife Emerald – I am forever indebted to you for your support throughout this process, and I will never forget the sacrifices you made to help me get to where I am today.
    [Show full text]
  • GABA Receptors
    D Reviews • BIOTREND Reviews • BIOTREND Reviews • BIOTREND Reviews • BIOTREND Reviews Review No.7 / 1-2011 GABA receptors Wolfgang Froestl , CNS & Chemistry Expert, AC Immune SA, PSE Building B - EPFL, CH-1015 Lausanne, Phone: +41 21 693 91 43, FAX: +41 21 693 91 20, E-mail: [email protected] GABA Activation of the GABA A receptor leads to an influx of chloride GABA ( -aminobutyric acid; Figure 1) is the most important and ions and to a hyperpolarization of the membrane. 16 subunits with γ most abundant inhibitory neurotransmitter in the mammalian molecular weights between 50 and 65 kD have been identified brain 1,2 , where it was first discovered in 1950 3-5 . It is a small achiral so far, 6 subunits, 3 subunits, 3 subunits, and the , , α β γ δ ε θ molecule with molecular weight of 103 g/mol and high water solu - and subunits 8,9 . π bility. At 25°C one gram of water can dissolve 1.3 grams of GABA. 2 Such a hydrophilic molecule (log P = -2.13, PSA = 63.3 Å ) cannot In the meantime all GABA A receptor binding sites have been eluci - cross the blood brain barrier. It is produced in the brain by decarb- dated in great detail. The GABA site is located at the interface oxylation of L-glutamic acid by the enzyme glutamic acid decarb- between and subunits. Benzodiazepines interact with subunit α β oxylase (GAD, EC 4.1.1.15). It is a neutral amino acid with pK = combinations ( ) ( ) , which is the most abundant combi - 1 α1 2 β2 2 γ2 4.23 and pK = 10.43.
    [Show full text]
  • A Posterior Probability of Linkage & Association Study
    A POSTERIOR PROBABILITY OF LINKAGE & ASSOCIATION STUDY OF 111 AUTISM CANDIDATE GENES B y FANG CHEN A dissertation submitted to the Graduate School – New Brunswick Rutgers, The State University of New Jersey and The Graduate School of Biomedical Sciences University of Medicine and Dentistry of New Jersey In partial fulfillment of the requirements For the degree of Doctor of Philosophy Graduate Program in Microbiology and Molecular Genetics Written under the direction of Dr. Tara C. Matise & Dr. Jay Tischfield And approved by ____________________ _____________________ ____________________ _____________________ ____________________ _____________________ New Brunswick, New Jersey May, 2009 ABSTRACT OF THE DISSERTATION A Posterior Probability of Linkage & Association Study of 111 Autism Candidate Genes B y FANG CHEN Dissertation directors: Dr. Tara C. Matise & Dr. Jay Tischfield Autism is a neurodevelopmental disorder with a complex genetic basis. In this study we investigated the possible involvement of 111 candidate genes in autism by studying 386 patient families from the Autism Genetic Resource Exchange (AGRE). These genes were selected based on their functions that relate to the neurotransmission or central developmental system. In phase 1 of the study, 1497 tagSNPs were selected to efficiently capture the haplotype information of each gene and were genotyped in 265 AGRE nuclear families. The cleaned genotype data were analyzed through the Kelvin program to compute values of Posterior Probability of Linkage (PPL) and Posterior Probability of LD given linkage (PPLD), which directly measure the probability of linkage and/or association. Consistent supportive evidence for linkage was observed for EPHB6-EPHA1 locus at the 7q34 region by two- and multi-point PPL analysis.
    [Show full text]
  • A 3-Fold Kernel Approach for Characterizing Late Onset Alzheimer’S Disease
    bioRxiv preprint doi: https://doi.org/10.1101/397760; this version posted August 22, 2018. 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-NC-ND 4.0 International license. A 3-fold kernel approach for characterizing Late Onset Alzheimer’s Disease Margherita Squillarioa,*, Federico Tomasia, Veronica Tozzoa, Annalisa Barlaa and Daniela Ubertib “for the Alzheimer’s Disease Neuroimaging Initiative**” aDIBRIS, University of Genoa, Via Dodecaneso 35, I-16146 Genova, Italy. E-mail address: {squillario, federico.tomasi, veronica.tozzo}@dibris.unige.it, [email protected] bDepartment of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy. E-mail address: [email protected] * Corresponding author and Lead Contact. Tel: +39-010-353-6707; Fax: +39-010-353- 6699. ** Data used in preparation of this article were obtained from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database (adni.loni.usc.edu). As such, the investigators within the ADNI contributed to the design and implementation of ADNI and/or provided data but did not participate in analysis or writing of this report. A complete listing of ADNI investigators can be found at: http://adni.loni.usc.edu/wp- content/uploads/how_to_apply/ADNI_Acknowledgement_List.pdf 1 bioRxiv preprint doi: https://doi.org/10.1101/397760; this version posted August 22, 2018. 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.
    [Show full text]
  • Research Article Microarray-Based Comparisons of Ion Channel Expression Patterns: Human Keratinocytes to Reprogrammed Hipscs To
    Hindawi Publishing Corporation Stem Cells International Volume 2013, Article ID 784629, 25 pages http://dx.doi.org/10.1155/2013/784629 Research Article Microarray-Based Comparisons of Ion Channel Expression Patterns: Human Keratinocytes to Reprogrammed hiPSCs to Differentiated Neuronal and Cardiac Progeny Leonhard Linta,1 Marianne Stockmann,1 Qiong Lin,2 André Lechel,3 Christian Proepper,1 Tobias M. Boeckers,1 Alexander Kleger,3 and Stefan Liebau1 1 InstituteforAnatomyCellBiology,UlmUniversity,Albert-EinsteinAllee11,89081Ulm,Germany 2 Institute for Biomedical Engineering, Department of Cell Biology, RWTH Aachen, Pauwelstrasse 30, 52074 Aachen, Germany 3 Department of Internal Medicine I, Ulm University, Albert-Einstein Allee 11, 89081 Ulm, Germany Correspondence should be addressed to Alexander Kleger; [email protected] and Stefan Liebau; [email protected] Received 31 January 2013; Accepted 6 March 2013 Academic Editor: Michael Levin Copyright © 2013 Leonhard Linta et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Ion channels are involved in a large variety of cellular processes including stem cell differentiation. Numerous families of ion channels are present in the organism which can be distinguished by means of, for example, ion selectivity, gating mechanism, composition, or cell biological function. To characterize the distinct expression of this group of ion channels we have compared the mRNA expression levels of ion channel genes between human keratinocyte-derived induced pluripotent stem cells (hiPSCs) and their somatic cell source, keratinocytes from plucked human hair. This comparison revealed that 26% of the analyzed probes showed an upregulation of ion channels in hiPSCs while just 6% were downregulated.
    [Show full text]
  • Developmental Deltamethrin: Effects on Cognition, Neurotransmitter Systems, Inflammatory Cytokines and Cell Death
    Developmental deltamethrin: Effects on cognition, neurotransmitter systems, inflammatory cytokines and cell death A dissertation submitted to the Graduate School of the University of Cincinnati In partial fulfillment of the requirements for the degree of Doctor of Philosophy In the Neuroscience Graduate Program of the College of Medicine By Emily Pitzer B.S. Westminster College April 2020 Dissertation Committee: Steve Danzer, Ph.D. Mary Beth Genter, Ph.D. Gary Gudelsky, Ph.D. Kimberly Yolton, Ph.D. Charles Vorhees, Ph.D. (Advisor) Michael Williams, Ph.D. (Chair) ABSTRACT Deltamethrin (DLM) is a Type II pyrethroid pesticide and is more widely used with the elimination of organophosphate pesticides. Epidemiological studies have linked elevated levels of pyrethroid metabolites in urine during development with neurological disorders, raising concern for the safety of children exposed to these agents. Few animal studies have explored the effects or mechanisms of DLM-induced deficits in behavior and cognition after developmental exposure. The aim of the present work is to examine the long-term effects of developmental (postnatal day (P) 3-20) DLM exposure in Sprague-Dawley rats on behavior, cognition, and cellular outcomes. First, the developmental effects of early DLM exposure on allocentric and egocentric learning and memory, locomotor activity, startle, conditioned freezing, and anxiety-like behaviors were assessed. The developmental effects of DLM on long-term potentiation (LTP) at P25-35, on adult dopamine (DA) release, monoamine levels, and mRNA levels of receptors/transporters/channels were then determined. In follow-up experiments, adult LTP, hippocampal glutamate release, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining for cell death, as well as DA and glutamate receptors, proinflammatory cytokines, and caspase-3 for protein expression were assessed.
    [Show full text]
  • Ion Channels
    UC Davis UC Davis Previously Published Works Title THE CONCISE GUIDE TO PHARMACOLOGY 2019/20: Ion channels. Permalink https://escholarship.org/uc/item/1442g5hg Journal British journal of pharmacology, 176 Suppl 1(S1) ISSN 0007-1188 Authors Alexander, Stephen PH Mathie, Alistair Peters, John A et al. Publication Date 2019-12-01 DOI 10.1111/bph.14749 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California S.P.H. Alexander et al. The Concise Guide to PHARMACOLOGY 2019/20: Ion channels. British Journal of Pharmacology (2019) 176, S142–S228 THE CONCISE GUIDE TO PHARMACOLOGY 2019/20: Ion channels Stephen PH Alexander1 , Alistair Mathie2 ,JohnAPeters3 , Emma L Veale2 , Jörg Striessnig4 , Eamonn Kelly5, Jane F Armstrong6 , Elena Faccenda6 ,SimonDHarding6 ,AdamJPawson6 , Joanna L Sharman6 , Christopher Southan6 , Jamie A Davies6 and CGTP Collaborators 1School of Life Sciences, University of Nottingham Medical School, Nottingham, NG7 2UH, UK 2Medway School of Pharmacy, The Universities of Greenwich and Kent at Medway, Anson Building, Central Avenue, Chatham Maritime, Chatham, Kent, ME4 4TB, UK 3Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK 4Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, A-6020 Innsbruck, Austria 5School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK 6Centre for Discovery Brain Science, University of Edinburgh, Edinburgh, EH8 9XD, UK Abstract The Concise Guide to PHARMACOLOGY 2019/20 is the fourth in this series of biennial publications. The Concise Guide provides concise overviews of the key properties of nearly 1800 human drug targets with an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties.
    [Show full text]
  • Cicuta Douglasii) Tubers
    Toxicon 108 (2015) 11e14 Contents lists available at ScienceDirect Toxicon journal homepage: www.elsevier.com/locate/toxicon Short communication The non-competitive blockade of GABAA receptors by an aqueous extract of water hemlock (Cicuta douglasii) tubers * Benedict T. Green a, , Camila Goulart b, 1, Kevin D. Welch a, James A. Pfister a, Isabelle McCollum a, Dale R. Gardner a a Poisonous Plant Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Logan, UT, USA b Graduate Program in Animal Science, Universidade Federal de Goias, Goiania,^ Goias, Brazil article info abstract Article history: Water hemlocks (Cicuta spp.) are acutely toxic members of the Umbellierae family; the toxicity is due to Received 22 July 2015 the presence of C17-polyacetylenes such as cicutoxin. There is only limited evidence of noncompetitive Received in revised form antagonism by C17-polyacetylenes at GABAA receptors. In this work with WSS-1 cells, we documented 9 September 2015 the noncompetitive blockade of GABA receptors by an aqueous extract of water hemlock (Cicuta dou- Accepted 14 September 2015 A glasii) and modulated the actions of the extract with a pretreatment of 10 mM midazolam. Available online 28 September 2015 Published by Elsevier Ltd. Keywords: Water hemlock Cicutoxin C17-polyacetylenes Benzodiazepines Barbiturates Midazolam Water hemlocks (Cicuta spp.) are acutely toxic members of the antagonists of the GABAA receptor by binding to the picrotoxin Umbellierae, or carrot family, that grow in wet habitats such as binding site within the chloride channel to block ion flow through streambeds or marshlands, and have been considered one of the the channel (Ratra et al., 2001; Chen et al., 2006; 2011; Olsen, most toxic plants of North America for many years (Kingsbury, 2006).
    [Show full text]
  • Structural Basis for Functional Modulation of Pentameric Ligand-Gated Ion Channels
    STRUCTURAL BASIS FOR FUNCTIONAL MODULATION OF PENTAMERIC LIGAND-GATED ION CHANNELS by YVONNE W. GICHERU Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Thesis Advisor: Sudha Chakrapani, Ph.D. Department of Physiology and Biophysics CASE WESTERN RESERVE UNIVERSITY May 2019 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of YVONNE W. GICHERU Candidate for the degree of Physiology and Biophysics* Witold Surewicz (Committee Chair) Matthias Buck Stephen Jones Vera Moiseenkova-Bell Rajesh Ramachandran Sudha Chakrapani March 27, 2019 *We also certify that written approval has been obtained for any proprietary material contained therein. Dedication To my family, friends, mentors, and all who have supported me through this process, thank you. Table of Contents List of Figures .................................................................................................... iv List of Abbreviations .......................................................................................... v Abstract .............................................................................................................. vi Chapter 1 ............................................................................................................. 1 Introduction .................................................................................................... 1 1.1 Pentameric ligand-gated ion channel (pLGIC) superfamily ...................... 2 1.2 pLGIC architecture
    [Show full text]
  • Neurochemical and Behavioral Features in Genetic Absence Epilepsy and in Acutely Induced Absence Seizures
    Hindawi Publishing Corporation ISRN Neurology Volume 2013, Article ID 875834, 48 pages http://dx.doi.org/10.1155/2013/875834 Review Article Neurochemical and Behavioral Features in Genetic Absence Epilepsy and in Acutely Induced Absence Seizures A. S. Bazyan1 and G. van Luijtelaar2 1 Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Science, Russian Federation, 5A Butlerov Street, Moscow 117485, Russia 2 Biological Psychology, Donders Centre for Cognition, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands Correspondence should be addressed to G. van Luijtelaar; [email protected] Received 21 January 2013; Accepted 6 February 2013 Academic Editors: R. L. Macdonald, Y. Wang, and E. M. Wassermann Copyright © 2013 A. S. Bazyan and G. van Luijtelaar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The absence epilepsy typical electroencephalographic pattern of sharp spikes and slow waves (SWDs) is considered to be dueto an interaction of an initiation site in the cortex and a resonant circuit in the thalamus. The hyperpolarization-activated cyclic nucleotide-gated cationic Ih pacemaker channels (HCN) play an important role in the enhanced cortical excitability. The role of thalamic HCN in SWD occurrence is less clear. Absence epilepsy in the WAG/Rij strain is accompanied by deficiency of the activity of dopaminergic system, which weakens the formation of an emotional positive state, causes depression-like symptoms, and counteracts learning and memory processes.
    [Show full text]
  • A Bioinformatics Model of Human Diseases on the Basis Of
    SUPPLEMENTARY MATERIALS A Bioinformatics Model of Human Diseases on the basis of Differentially Expressed Genes (of Domestic versus Wild Animals) That Are Orthologs of Human Genes Associated with Reproductive-Potential Changes Vasiliev1,2 G, Chadaeva2 I, Rasskazov2 D, Ponomarenko2 P, Sharypova2 E, Drachkova2 I, Bogomolov2 A, Savinkova2 L, Ponomarenko2,* M, Kolchanov2 N, Osadchuk2 A, Oshchepkov2 D, Osadchuk2 L 1 Novosibirsk State University, Novosibirsk 630090, Russia; 2 Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia; * Correspondence: [email protected]. Tel.: +7 (383) 363-4963 ext. 1311 (M.P.) Supplementary data on effects of the human gene underexpression or overexpression under this study on the reproductive potential Table S1. Effects of underexpression or overexpression of the human genes under this study on the reproductive potential according to our estimates [1-5]. ↓ ↑ Human Deficit ( ) Excess ( ) # Gene NSNP Effect on reproductive potential [Reference] ♂♀ NSNP Effect on reproductive potential [Reference] ♂♀ 1 increased risks of preeclampsia as one of the most challenging 1 ACKR1 ← increased risk of atherosclerosis and other coronary artery disease [9] ← [3] problems of modern obstetrics [8] 1 within a model of human diseases using Adcyap1-knockout mice, 3 in a model of human health using transgenic mice overexpressing 2 ADCYAP1 ← → [4] decreased fertility [10] [4] Adcyap1 within only pancreatic β-cells, ameliorated diabetes [11] 2 within a model of human diseases
    [Show full text]