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Leynse AK, Mudge EM, Turner AD, Maskrey BH, Robertson A. Gambierone and Sodium Channel Specific Bioactivity Are Associated with the Extracellular Metabolite Pool of the Marine Dinoflagellate Coolia palmyrensis. Mar Drugs 2023; 21:md21040244. [PMID: 37103383 PMCID: PMC10143066 DOI: 10.3390/md21040244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 04/28/2023] Open
Abstract
Tropical epibenthic dinoflagellate communities produce a plethora of bioactive secondary metabolites, including the toxins ciguatoxins (CTXs) and potentially gambierones, that can contaminate fishes, leading to ciguatera poisoning (CP) when consumed by humans. Many studies have assessed the cellular toxicity of causative dinoflagellate species to better understand the dynamics of CP outbreaks. However, few studies have explored extracellular toxin pools which may also enter the food web, including through alternative and unanticipated routes of exposure. Additionally, the extracellular exhibition of toxins would suggest an ecological function and may prove important to the ecology of the CP-associated dinoflagellate species. In this study, semi-purified extracts obtained from the media of a Coolia palmyrensis strain (DISL57) isolated from the U.S. Virgin Islands were assessed for bioactivity via a sodium channel specific mouse neuroblastoma cell viability assay and associated metabolites evaluated by targeted and non-targeted liquid chromatography tandem and high-resolution mass spectrometry. We found that extracts of C. palmyrensis media exhibit both veratrine enhancing bioactivity and non-specific bioactivity. LC-HR-MS analysis of the same extract fractions identified gambierone and multiple undescribed peaks with mass spectral characteristics suggestive of structural similarities to polyether compounds. These findings implicate C. palmyrensis as a potential contributor to CP and highlight extracellular toxin pools as a potentially significant source of toxins that may enter the food web through multiple exposure pathways.
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Affiliation(s)
- Alexander K Leynse
- School of Marine & Environmental Sciences, University of South Alabama, 600 Clinic Drive, Mobile, AL 36688, USA
- Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL 36528, USA
| | - Elizabeth M Mudge
- National Research Council of Canada, 1411 Oxford Street, Halifax, NS B3M3Z1, Canada
| | - Andrew D Turner
- Center for the Environment, Fisheries, and Aquaculture Science, Barrack Road, Weymouth DT4 8UB, UK
| | - Benjamin H Maskrey
- Center for the Environment, Fisheries, and Aquaculture Science, Barrack Road, Weymouth DT4 8UB, UK
| | - Alison Robertson
- School of Marine & Environmental Sciences, University of South Alabama, 600 Clinic Drive, Mobile, AL 36688, USA
- Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL 36528, USA
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2
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Raposo-Garcia S, Costas C, Louzao MC, Vale C, Botana LM. Synergistic effect of environmental food pollutants: Pesticides and marine biotoxins. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:160111. [PMID: 36370778 DOI: 10.1016/j.scitotenv.2022.160111] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/24/2022] [Accepted: 11/06/2022] [Indexed: 06/16/2023]
Abstract
Emerging marine biotoxins such as ciguatoxins and pyrethroid compounds, widely used in agriculture, are independently treated as environmental toxicants. Their maximum residue levels in food components are set without considering their possible synergistic effects as consequence of their interaction with the same cellular target. There is an absolute lack of data on the possible combined cellular effects that biological and chemical pollutants, may have. Nowadays, an increasing presence of ciguatoxins in European Coasts has been reported and these toxins can affect human health. Similarly, the increasing use of phytosanitary products for control of food plagues has raised exponentially during the last decades due to climate change. The lack of data and regulation evaluating the combined effect of environmental pollutants with the same molecular target led us to analyse their in vitro effects. In this work, the effects of ciguatoxins and pyrethroids in human sodium channels were investigated. The results presented in this study indicate that both types of compounds have a profound synergistic effect in voltage-dependent sodium channels. These food pollutants act by decreasing the maximum peak inward sodium currents and hyperpolarizing the sodium channels activation, effects that are boosted by the simultaneous presence of both compounds. A fact that highlights the need to re-evaluate their limits in feedstock as well as their potential in vivo toxicity considering that they act on the same cellular target. Moreover, this work sets the cellular basis to further apply this type of studies to other water and food pollutants that may act synergistically and thus implement the corresponding regulatory limits taking into account its presence in a healthy diet.
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Affiliation(s)
- Sandra Raposo-Garcia
- Departamento de Farmacologı́a, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Celia Costas
- Departamento de Farmacologı́a, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - M Carmen Louzao
- Departamento de Farmacologı́a, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain
| | - Carmen Vale
- Departamento de Farmacologı́a, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain.
| | - Luis M Botana
- Departamento de Farmacologı́a, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, Spain.
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3
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Loser D, Schaefer J, Danker T, Möller C, Brüll M, Suciu I, Ückert AK, Klima S, Leist M, Kraushaar U. Human neuronal signaling and communication assays to assess functional neurotoxicity. Arch Toxicol 2021; 95:229-252. [PMID: 33269408 PMCID: PMC7811517 DOI: 10.1007/s00204-020-02956-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/16/2020] [Indexed: 01/08/2023]
Abstract
Prediction of drug toxicity on the human nervous system still relies mainly on animal experiments. Here, we developed an alternative system allowing assessment of complex signaling in both individual human neurons and on the network level. The LUHMES cultures used for our approach can be cultured in 384-well plates with high reproducibility. We established here high-throughput quantification of free intracellular Ca2+ concentrations [Ca2+]i as broadly applicable surrogate of neuronal activity and verified the main processes by patch clamp recordings. Initially, we characterized the expression pattern of many neuronal signaling components and selected the purinergic receptors to demonstrate the applicability of the [Ca2+]i signals for quantitative characterization of agonist and antagonist responses on classical ionotropic neurotransmitter receptors. This included receptor sub-typing and the characterization of the anti-parasitic drug suramin as modulator of the cellular response to ATP. To exemplify potential studies on ion channels, we characterized voltage-gated sodium channels and their inhibition by tetrodotoxin, saxitoxin and lidocaine, as well as their opening by the plant alkaloid veratridine and the food-relevant marine biotoxin ciguatoxin. Even broader applicability of [Ca2+]i quantification as an end point was demonstrated by measurements of dopamine transporter activity based on the membrane potential-changing activity of this neurotransmitter carrier. The substrates dopamine or amphetamine triggered [Ca2+]i oscillations that were synchronized over the entire culture dish. We identified compounds that modified these oscillations by interfering with various ion channels. Thus, this new test system allows multiple types of neuronal signaling, within and between cells, to be assessed, quantified and characterized for their potential disturbance.
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Affiliation(s)
- Dominik Loser
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
- Life Sciences Faculty, Albstadt-Sigmaringen University, 72488, Sigmaringen, Germany
| | - Jasmin Schaefer
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, 72770, Reutlingen, Germany
- NMI TT GmbH, 72770, Reutlingen, Germany
| | | | - Clemens Möller
- Life Sciences Faculty, Albstadt-Sigmaringen University, 72488, Sigmaringen, Germany
| | - Markus Brüll
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Constance, Germany
| | - Ilinca Suciu
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Constance, Germany
| | - Anna-Katharina Ückert
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Constance, Germany
| | - Stefanie Klima
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Constance, Germany
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Universitaetsstr. 10, 78457, Constance, Germany.
| | - Udo Kraushaar
- NMI Natural and Medical Sciences Institute at the University of Tuebingen, 72770, Reutlingen, Germany
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4
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L’Herondelle K, Talagas M, Mignen O, Misery L, Le Garrec R. Neurological Disturbances of Ciguatera Poisoning: Clinical Features and Pathophysiological Basis. Cells 2020; 9:E2291. [PMID: 33066435 PMCID: PMC7602189 DOI: 10.3390/cells9102291] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/07/2020] [Accepted: 10/12/2020] [Indexed: 12/12/2022] Open
Abstract
Ciguatera fish poisoning (CFP), the most prevalent seafood poisoning worldwide, is caused by the consumption of tropical and subtropical fish contaminated with potent neurotoxins called ciguatoxins (CTXs). Ciguatera is a complex clinical syndrome in which peripheral neurological signs predominate in the acute phase of the intoxication but also persist or reoccur long afterward. Their recognition is of particular importance in establishing the diagnosis, which is clinically-based and can be a challenge for physicians unfamiliar with CFP. To date, no specific treatment exists. Physiopathologically, the primary targets of CTXs are well identified, as are the secondary events that may contribute to CFP symptomatology. This review describes the clinical features, focusing on the sensory disturbances, and then reports on the neuronal targets and effects of CTXs, as well as the neurophysiological and histological studies that have contributed to existing knowledge of CFP neuropathophysiology at the molecular, neurocellular and nerve levels.
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Affiliation(s)
- Killian L’Herondelle
- University of Brest, School of Medicine, Laboratoire Interactions Epithéliums-Neurones (Univ Brest, LIEN), F-29200 Brest, France; (K.L.); (M.T.); (L.M.)
| | - Matthieu Talagas
- University of Brest, School of Medicine, Laboratoire Interactions Epithéliums-Neurones (Univ Brest, LIEN), F-29200 Brest, France; (K.L.); (M.T.); (L.M.)
- Department of Dermatology, University Hospital of Brest, F-29200 Brest, France
| | - Olivier Mignen
- University of Brest, School of Medicine, INSERM U1227, Lymphocytes B et auto-immunité, F-29200 Brest, France;
| | - Laurent Misery
- University of Brest, School of Medicine, Laboratoire Interactions Epithéliums-Neurones (Univ Brest, LIEN), F-29200 Brest, France; (K.L.); (M.T.); (L.M.)
- Department of Dermatology, University Hospital of Brest, F-29200 Brest, France
| | - Raphaele Le Garrec
- University of Brest, School of Medicine, Laboratoire Interactions Epithéliums-Neurones (Univ Brest, LIEN), F-29200 Brest, France; (K.L.); (M.T.); (L.M.)
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5
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Murk AJ, Nicolas J, Smulders FJ, Bürk C, Gerssen A. Marine biotoxins: types of poisoning, underlying mechanisms of action and risk management programmes. CHEMICAL HAZARDS IN FOODS OF ANIMAL ORIGIN 2019. [DOI: 10.3920/978-90-8686-877-3_09] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Albertinka J. Murk
- Department of Animal Sciences, Marine Animal Ecology group, Wageningen University and Research, P.O. Box 338, 6700 AH Wageningen, the Netherlands
| | - Jonathan Nicolas
- 68300 Saint-Louis, France, formerly affiliated with Division of Toxicology, Wageningen University and Research Centre, the Netherlands
| | - Frans J.M. Smulders
- Institute of Meat Hygiene, Meat Technology and Food Science, Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria
| | - Christine Bürk
- Milchwirstschaftliche Untersuchungs- und Versuchsanstalt (MUVA) Kempten, GmbH, Ignaz-Kiechle-Straße 20-22, 87437 Kempten (Allgäu), Germany
| | - Arjen Gerssen
- RIKILT, Wageningen University & Research, P.O. Box 230, 6708 WB Wageningen, the Netherlands
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6
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Gatti CMI, Lonati D, Darius HT, Zancan A, Roué M, Schicchi A, Locatelli CA, Chinain M. Tectus niloticus (Tegulidae, Gastropod) as a Novel Vector of Ciguatera Poisoning: Clinical Characterization and Follow-Up of a Mass Poisoning Event in Nuku Hiva Island (French Polynesia). Toxins (Basel) 2018; 10:E102. [PMID: 29495579 PMCID: PMC5869390 DOI: 10.3390/toxins10030102] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/19/2018] [Accepted: 02/23/2018] [Indexed: 01/19/2023] Open
Abstract
Ciguatera fish poisoning (CFP) is the most prevalent non-bacterial food-borne form of poisoning in French Polynesia, which results from the consumption of coral reef fish naturally contaminated with ciguatoxins produced by dinoflagellates in the genus Gambierdiscus. Since the early 2000s, this French territory has also witnessed the emergence of atypical forms of ciguatera, known as ciguatera shellfish poisoning (CSP), associated with the consumption of marine invertebrates. In June 2014, nine tourists simultaneously developed a major and persistent poisoning syndrome following the consumption of the gastropod Tectus niloticus collected in Anaho, a secluded bay of Nuku Hiva Island (Marquesas Archipelago, French Polynesia). The unusual nature and severity of this event prompted a multidisciplinary investigation in order to characterize the etiology and document the short/long-term health consequences of this mass-poisoning event. This paper presents the results of clinical investigations based on hospital medical records, medical follow-up conducted six and 20 months post-poisoning, including a case description. This study is the first to describe the medical signature of T. niloticus poisoning in French Polynesia and contributed to alerting local authorities about the potential health hazards associated with the consumption of this gastropod, which is highly prized by local communities in Pacific island countries and territories.
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Affiliation(s)
- Clémence Mahana Iti Gatti
- Laboratory of Toxic Microalgae, Institut Louis Malardé (ILM)-UMR 241-EIO, P.O. box 30, 98713 Papeete, Tahiti, French Polynesia.
| | - Davide Lonati
- Poison Control Centre and National Toxicology Information Centre-Toxicology Unit, Istituti Clinici Scientifici Maugeri, IRCCS Maugeri Hospital and University of Pavia, 27100 Pavia, Italy.
| | - Hélène Taiana Darius
- Laboratory of Toxic Microalgae, Institut Louis Malardé (ILM)-UMR 241-EIO, P.O. box 30, 98713 Papeete, Tahiti, French Polynesia.
| | - Arturo Zancan
- Subacute Care Unit, Istituti Clinici Scientifici Maugeri, IRCCS Maugeri Hospital, 27100 Pavia, Italy.
| | - Mélanie Roué
- Institut de Recherche pour le Développement (IRD)-UMR 241-EIO, P.O. box 529, 98713 Papeete, Tahiti, French Polynesia.
| | - Azzurra Schicchi
- Poison Control Centre and National Toxicology Information Centre-Toxicology Unit, Istituti Clinici Scientifici Maugeri, IRCCS Maugeri Hospital and University of Pavia, 27100 Pavia, Italy.
| | - Carlo Alessandro Locatelli
- Poison Control Centre and National Toxicology Information Centre-Toxicology Unit, Istituti Clinici Scientifici Maugeri, IRCCS Maugeri Hospital and University of Pavia, 27100 Pavia, Italy.
| | - Mireille Chinain
- Laboratory of Toxic Microalgae, Institut Louis Malardé (ILM)-UMR 241-EIO, P.O. box 30, 98713 Papeete, Tahiti, French Polynesia.
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7
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Inserra MC, Israel MR, Caldwell A, Castro J, Deuis JR, Harrington AM, Keramidas A, Garcia-Caraballo S, Maddern J, Erickson A, Grundy L, Rychkov GY, Zimmermann K, Lewis RJ, Brierley SM, Vetter I. Multiple sodium channel isoforms mediate the pathological effects of Pacific ciguatoxin-1. Sci Rep 2017; 7:42810. [PMID: 28225079 PMCID: PMC5320492 DOI: 10.1038/srep42810] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/13/2017] [Indexed: 01/04/2023] Open
Abstract
Human intoxication with the seafood poison ciguatoxin, a dinoflagellate polyether that activates voltage-gated sodium channels (NaV), causes ciguatera, a disease characterised by gastrointestinal and neurological disturbances. We assessed the activity of the most potent congener, Pacific ciguatoxin-1 (P-CTX-1), on NaV1.1–1.9 using imaging and electrophysiological approaches. Although P-CTX-1 is essentially a non-selective NaV toxin and shifted the voltage-dependence of activation to more hyperpolarising potentials at all NaV subtypes, an increase in the inactivation time constant was observed only at NaV1.8, while the slope factor of the conductance-voltage curves was significantly increased for NaV1.7 and peak current was significantly increased for NaV1.6. Accordingly, P-CTX-1-induced visceral and cutaneous pain behaviours were significantly decreased after pharmacological inhibition of NaV1.8 and the tetrodotoxin-sensitive isoforms NaV1.7 and NaV1.6, respectively. The contribution of these isoforms to excitability of peripheral C- and A-fibre sensory neurons, confirmed using murine skin and visceral single-fibre recordings, reflects the expression pattern of NaV isoforms in peripheral sensory neurons and their contribution to membrane depolarisation, action potential initiation and propagation.
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Affiliation(s)
- Marco C Inserra
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd, St Lucia, Queensland 4072, Australia
| | - Mathilde R Israel
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd, St Lucia, Queensland 4072, Australia
| | - Ashlee Caldwell
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Joel Castro
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Jennifer R Deuis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd, St Lucia, Queensland 4072, Australia
| | - Andrea M Harrington
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Angelo Keramidas
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Sonia Garcia-Caraballo
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Jessica Maddern
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Andelain Erickson
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Luke Grundy
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Grigori Y Rychkov
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Katharina Zimmermann
- Klinik für Anästhesiologie am Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Richard J Lewis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd, St Lucia, Queensland 4072, Australia
| | - Stuart M Brierley
- Visceral Pain Group, South Australian Health and Medical Research Institute (SAHMRI), School of Medicine, Flinders University, Adelaide, South Australia 5000, Australia.,Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia 5000, Australia
| | - Irina Vetter
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd, St Lucia, Queensland 4072, Australia.,School of Pharmacy, The University of Queensland, 20 Cornwall St, Woolloongabba, Queensland 4102, Australia
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8
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Martín V, Vale C, Rubiolo JA, Roel M, Hirama M, Yamashita S, Vieytes MR, Botana LM. Chronic Ciguatoxin Treatment Induces Synaptic Scaling through Voltage Gated Sodium Channels in Cortical Neurons. Chem Res Toxicol 2015; 28:1109-19. [DOI: 10.1021/tx500506q] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Víctor Martín
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Carmen Vale
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Juan A. Rubiolo
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Maria Roel
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Masahiro Hirama
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Shuji Yamashita
- Department
of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Mercedes R. Vieytes
- Departamento
de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Luís M. Botana
- Departamento
de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
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9
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Martín V, Vale C, Hirama M, Yamashita S, Rubiolo JA, Vieytes MR, Botana LM. Synthetic ciguatoxin CTX 3C induces a rapid imbalance in neuronal excitability. Chem Res Toxicol 2015; 28:1095-108. [PMID: 25945403 DOI: 10.1021/tx500503d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ciguatera is a human global disease caused by the consumption of contaminated fish that have accumulated ciguatoxins (CTXs), sodium channel activator toxins. Symptoms of ciguatera include neurological alterations such as paraesthesiae, dysaesthesiae, depression, and heightened nociperception, among others. An important issue to understand these long-term neurological alterations is to establish the role that changes in activity produced by CTX 3C represent to neurons. Here, the effects of synthetic ciguatoxin CTX 3C on membrane potential, spontaneous spiking, and properties of synaptic transmission in cultured cortical neurons of 11-18 days in vitro (DIV) were evaluated using electrophysiological approaches. CTX 3C induced a large depolarization that decreased neuronal firing and caused a rapid inward tonic current that was primarily GABAergic. Moreover, the toxin enhanced the amplitude of miniature postsynaptic inhibitory currents (mIPSCs), whereas it decreased the amplitude of miniature postsynaptic excitatory currents (mEPSCs). The frequency of mIPSCs increased, whereas the frequency of mEPSCs remained unaltered. We describe, for the first time, that a rapid membrane depolarization caused by CTX 3C in cortical neurons activates mechanisms that tend to suppress electrical activity by shifting the balance between excitatory and inhibitory synaptic transmission toward inhibition. Indeed, these results suggest that the acute effects of CTX on synaptic transmission could underlie some of the neurological symptoms caused by ciguatera in humans.
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Affiliation(s)
- Victor Martín
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Carmen Vale
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Masahiro Hirama
- ‡Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Shuji Yamashita
- ‡Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Juan Andrés Rubiolo
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Mercedes R Vieytes
- §Departamento de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Luis M Botana
- †Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
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10
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Mattei C, Molgó J, Benoit E. Involvement of both sodium influx and potassium efflux in ciguatoxin-induced nodal swelling of frog myelinated axons. Neuropharmacology 2014; 85:417-26. [PMID: 24950451 DOI: 10.1016/j.neuropharm.2014.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/09/2014] [Accepted: 06/02/2014] [Indexed: 01/22/2023]
Abstract
Ciguatoxins, mainly produced by benthic dinoflagellate Gambierdiscus species, are responsible for a complex human poisoning known as ciguatera. Previous pharmacological studies revealed that these toxins activate voltage-gated Na+ channels. In frog nodes of Ranvier, ciguatoxins induce spontaneous and repetitive action potentials (APs) and increase axonal volume that may explain alterations of nerve functioning in intoxicated humans. The present study aimed determining the ionic mechanisms involved in Pacific ciguatoxin-1B (P-CTX-1B)-induced membrane hyperexcitability and subsequent volume increase in frog nodes of Ranvier, using electrophysiology and confocal microscopy. The results reveal that P-CTX-1B action is not dependent on external Cl- ions since it was not affected by substituting Cl- by methylsulfate ions. In contrast, substitution of external Na+ by Li+ ions suppressed spontaneous APs and prevented nodal swelling. This suggests that P-CTX-1B-modified Na+ channels are not selective to Li+ ions and/or are blocked by these ions, and that Na+ influx through Na+ channels opened during spontaneous APs is required for axonal swelling. The fact that the K+ channel blocker tetraethylammonium modified, but did not suppress, spontaneous APs and greatly reduced nodal swelling induced by P-CTX-1B indicates that K+ efflux might also be involved. This is supported by the fact that P-CTX-1B, when tested in the presence of both tetraethylammonium and the K+ ionophore valinomycin, produced the characteristic nodal swelling. It is concluded that, during the action of P-CTX-1B, water movements responsible for axonal swelling depend on both Na+ influx and K+ efflux. These results pave the way for further studies regarding ciguatera treatment.
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Affiliation(s)
- César Mattei
- CNRS, Institut de Neurobiologie Alfred Fessard - FRC2118, Laboratoire de Neurobiologie et Développement - UPR3294, 91198 Gif-sur-Yvette cedex, France; Laboratoire Biologie Neurovasculaire et Mitochondriale Intégrée, UMR CNRS 6214 INSERM 1083, Université d'Angers, 49045 Angers cedex 01, France.
| | - Jordi Molgó
- CNRS, Institut de Neurobiologie Alfred Fessard - FRC2118, Laboratoire de Neurobiologie et Développement - UPR3294, 91198 Gif-sur-Yvette cedex, France
| | - Evelyne Benoit
- CNRS, Institut de Neurobiologie Alfred Fessard - FRC2118, Laboratoire de Neurobiologie et Développement - UPR3294, 91198 Gif-sur-Yvette cedex, France
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Ciguatera: A public health perspective. Toxicon 2010; 56:123-36. [DOI: 10.1016/j.toxicon.2009.09.008] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Revised: 09/15/2009] [Accepted: 09/18/2009] [Indexed: 11/19/2022]
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Mattei C, Wen PJ, Nguyen-Huu TD, Alvarez M, Benoit E, Bourdelais AJ, Lewis RJ, Baden DG, Molgó J, Meunier FA. Brevenal inhibits pacific ciguatoxin-1B-induced neurosecretion from bovine chromaffin cells. PLoS One 2008; 3:e3448. [PMID: 18941627 PMCID: PMC2565126 DOI: 10.1371/journal.pone.0003448] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/19/2008] [Indexed: 11/20/2022] Open
Abstract
Ciguatoxins and brevetoxins are neurotoxic cyclic polyether compounds produced by dinoflagellates, which are responsible for ciguatera and neurotoxic shellfish poisoning (NSP) respectively. Recently, brevenal, a natural compound was found to specifically inhibit brevetoxin action and to have a beneficial effect in NSP. Considering that brevetoxin and ciguatoxin specifically activate voltage-sensitive Na+ channels through the same binding site, brevenal has therefore a good potential for the treatment of ciguatera. Pacific ciguatoxin-1B (P-CTX-1B) activates voltage-sensitive Na+ channels and promotes an increase in neurotransmitter release believed to underpin the symptoms associated with ciguatera. However, the mechanism through which slow Na+ influx promotes neurosecretion is not fully understood. In the present study, we used chromaffin cells as a model to reconstitute the sequence of events culminating in ciguatoxin-evoked neurosecretion. We show that P-CTX-1B induces a tetrodotoxin-sensitive rise in intracellular Na+, closely followed by an increase in cytosolic Ca2+ responsible for promoting SNARE-dependent catecholamine secretion. Our results reveal that brevenal and β-naphtoyl-brevetoxin prevent P-CTX-1B secretagogue activity without affecting nicotine or barium-induced catecholamine secretion. Brevenal is therefore a potent inhibitor of ciguatoxin-induced neurotoxic effect and a potential treatment for ciguatera.
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Affiliation(s)
- César Mattei
- CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie Cellulaire et Moléculaire, Gif-sur-Yvette, France
| | - Peter J. Wen
- Queensland Brain Institute and School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Truong D. Nguyen-Huu
- Queensland Brain Institute and School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Martha Alvarez
- Queensland Brain Institute and School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
- Photonics and Mathematical Optics Group, Tecnológico de Monterrey, Monterrey, México
| | - Evelyne Benoit
- CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie Cellulaire et Moléculaire, Gif-sur-Yvette, France
| | - Andrea J. Bourdelais
- Center for Marine Science, University of North Carolina at Wilmington, Wilmington, North Carolina, United States of America
| | - Richard J. Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Daniel G. Baden
- Center for Marine Science, University of North Carolina at Wilmington, Wilmington, North Carolina, United States of America
| | - Jordi Molgó
- CNRS, Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie Cellulaire et Moléculaire, Gif-sur-Yvette, France
- * E-mail: (JM); (FAM)
| | - Frédéric A. Meunier
- Queensland Brain Institute and School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
- * E-mail: (JM); (FAM)
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LePage KT, Rainier JD, Johnson HWB, Baden DG, Murray TF. Gambierol acts as a functional antagonist of neurotoxin site 5 on voltage-gated sodium channels in cerebellar granule neurons. J Pharmacol Exp Ther 2007; 323:174-9. [PMID: 17609421 DOI: 10.1124/jpet.107.124271] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The marine toxin gambierol, a polyether ladder toxin derived from the marine dinoflagellate Gambierdiscus toxicus, was evaluated for interaction with voltage-gated sodium channels (VGSCs) in cerebellar granule neuron (CGN) cultures. At concentrations ranging from 10 nM to 10 microM, gambierol alone had no effect on the intracellular Ca2+ concentration [Ca2+]i of exposed CGN cultures. Furthermore, there was no evidence of neurotoxicity in CGN cultures exposed for 2 h to gambierol (1 nM-10 microM). However, gambierol was a potent inhibitor (IC50 = 189 nM) of the elevation of [Ca2+]i that accompanies exposure of CGN cultures to the VGSC activator brevetoxin-2 (PbTx-2). To further explore the potential interaction of gambierol with VGSCs, the influence of gambierol on PbTx-2-induced neurotoxicity was assessed. Gambierol reduced the PbTx-2-induced efflux of lactate dehydrogenase in exposed CGN cultures in a concentration-dependent manner (IC50 = 471 nM). It is noteworthy that the potencies of gambierol as an inhibitor of both PbTx-2-induced Ca2+ influx and cytotoxicity were coincident. Finally, the inhibitory effects of gambierol on PbTx-2-induced elevation of [Ca2+]i were compared with those of brevenal, a natural inhibitor of the toxic effects of brevetoxin isolated from cultures of Karina brevis. Like gambierol, brevenal inhibited PbTx-2-induced elevation of [Ca2+]i in a concentration-dependent manner (IC50 = 108.6 nM). These results provide evidence for gambierol acting as a functional antagonist of neurotoxin site 5 on neuronal VGSCs.
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Affiliation(s)
- K T LePage
- Department of Biology, Xavier University of Louisiana, New Orleans, Louisiana, USA
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Abstract
Ciguatera is a global disease caused by the consumption of certain warm-water fish that have accumulated orally effective levels of sodium channel activator toxins (ciguatoxins) through the marine food chain. Symptoms of ciguatera arising from the consumption of ciguateric fish include a range of gastrointestinal, neurological and cardiovascular disturbances. This review examines progress in our understanding of ciguatera from an Australian perspective, especially the laboratory-based research into the problem that was initiated by the late "Bob" Endean at the University of Queensland.
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Affiliation(s)
- Richard J Lewis
- Institute for Molecular Biosciences, The University of Queensland, Qld. 4072, Australia.
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Louzao MC, Cagide E, Vieytes MR, Sasaki M, Fuwa H, Yasumoto T, Botana LM. The Sodium Channel of Human Excitable Cells is a Target for Gambierol. Cell Physiol Biochem 2006; 17:257-68. [PMID: 16791001 DOI: 10.1159/000094138] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Gambierol is a polycyclic ether toxin with the same biogenetic origin as ciguatoxins. Gambierol has been associated with neurological symptoms in humans even though its mechanism of action has not been fully characterized. METHODS We studied the effect of gambierol in human neuroblastoma cells by using bis-oxonol to measure membrane potential and FURA-2 to monitor intracellular calcium. RESULTS We found that this toxin: i) produced a membrane depolarization, ii) potentiated the effect of veratridine on membrane potential iii) decreased ciguatoxin-induced depolarization and iv) increased cytosolic calcium in neuroblastoma cells. CONCLUSION These results indicate that gambierol modulate ion fluxes by acting as a partial agonist of sodium channels.
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Affiliation(s)
- M Carmen Louzao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain
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Birinyi-Strachan LC, Davies MJ, Lewis RJ, Nicholson GM. Neuroprotectant effects of iso-osmolar D-mannitol to prevent Pacific ciguatoxin-1 induced alterations in neuronal excitability: a comparison with other osmotic agents and free radical scavengers. Neuropharmacology 2005; 49:669-86. [PMID: 15950247 DOI: 10.1016/j.neuropharm.2005.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Revised: 02/12/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
The basis for the neuroprotectant effect of D-mannitol in reducing the sensory neurological disturbances seen in ciguatera poisoning, is unclear. Pacific ciguatoxin-1 (P-CTX-1), at a concentration 10 nM, caused a statistically significant swelling of rat sensory dorsal root ganglia (DRG) neurons that was reversed by hyperosmolar 50 mM D-mannitol. However, using electron paramagnetic resonance (EPR) spectroscopy, it was found that P-CTX-1 failed to generate hydroxyl free radicals at concentrations of toxin that caused profound effects on neuronal excitability. Whole-cell patch-clamp recordings from DRG neurons revealed that both hyper- and iso-osmolar 50 mM D-mannitol prevented the membrane depolarisation and repetitive firing of action potentials induced by P-CTX-1. In addition, both hyper- and iso-osmolar 50 mM D-mannitol prevented the hyperpolarising shift in steady-state inactivation and the rise in leakage current through tetrodotoxin (TTX)-sensitive Na(v) channels, as well as the increased rate of recovery from inactivation of TTX-resistant Na(v) channels induced by P-CTX-1. D-Mannitol also reduced, but did not prevent, the inhibition of peak TTX-sensitive and TTX-resistant I(Na) amplitude by P-CTX-1. Additional experiments using hyper- and iso-osmolar D-sorbitol, hyperosmolar sucrose and the free radical scavenging agents Trolox and L-ascorbic acid showed that these agents, unlike D-mannitol, failed to prevent the effects of P-CTX-1 on spike electrogenesis and Na(v) channel gating. These selective actions of D-mannitol indicate that it does not act purely as an osmotic agent to reduce swelling of nerves, but involves a more complex action dependent on the Na(v) channel subtype, possibly to alter or reduce toxin association.
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Affiliation(s)
- Liesl C Birinyi-Strachan
- Neurotoxin Research Group, Department of Health Sciences, University of Technology, Sydney, Broadway, NSW, Australia
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18
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Birinyi-Strachan LC, Gunning SJ, Lewis RJ, Nicholson GM. Block of voltage-gated potassium channels by Pacific ciguatoxin-1 contributes to increased neuronal excitability in rat sensory neurons. Toxicol Appl Pharmacol 2005; 204:175-86. [PMID: 15808523 DOI: 10.1016/j.taap.2004.08.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Accepted: 08/31/2004] [Indexed: 10/26/2022]
Abstract
The present study investigated the actions of the polyether marine toxin Pacific ciguatoxin-1 (P-CTX-1) on neuronal excitability in rat dorsal root ganglion (DRG) neurons using patch-clamp recording techniques. Under current-clamp conditions, bath application of 2-20 nM P-CTX-1 caused a rapid, concentration-dependent depolarization of the resting membrane potential in neurons expressing tetrodotoxin (TTX)-sensitive voltage-gated sodium (Nav) channels. This action was completely suppressed by the addition of 200 nM TTX to the external solution, indicating that this effect was mediated through TTX-sensitive Nav channels. In addition, P-CTX-1 also prolonged action potential and afterhyperpolarization (AHP) duration. In a subpopulation of neurons, P-CTX-1 also produced tonic action potential firing, an effect that was not accompanied by significant oscillation of the resting membrane potential. Conversely, in neurons expressing TTX-resistant Nav currents, P-CTX-1 failed to alter any parameter of neuronal excitability examined in this study. Under voltage-clamp conditions in rat DRG neurons, P-CTX-1 inhibited both delayed-rectifier and 'A-type' potassium currents in a dose-dependent manner, actions that occurred in the absence of alterations to the voltage dependence of activation. These actions appear to underlie the prolongation of the action potential and AHP, and contribute to repetitive firing. These data indicate that a block of potassium channels contributes to the increase in neuronal excitability, associated with a modulation of Nav channel gating, observed clinically in response to ciguatera poisoning.
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MESH Headings
- Action Potentials/drug effects
- Action Potentials/physiology
- Animals
- Animals, Newborn
- Ciguatoxins/antagonists & inhibitors
- Ciguatoxins/pharmacology
- Dose-Response Relationship, Drug
- Eels
- Electrophysiology/methods
- Female
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/physiology
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- NAV1.5 Voltage-Gated Sodium Channel
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Patch-Clamp Techniques/methods
- Potassium Channel Blockers/adverse effects
- Potassium Channel Blockers/chemistry
- Potassium Channels, Voltage-Gated/antagonists & inhibitors
- Potassium Channels, Voltage-Gated/drug effects
- Potassium Channels, Voltage-Gated/physiology
- Rats
- Rats, Wistar
- Sodium Channels/drug effects
- Sodium Channels/physiology
- Tetrodotoxin/pharmacology
- Time Factors
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Affiliation(s)
- Liesl C Birinyi-Strachan
- Neurotoxin Research Group, Department of Health Sciences, University of Technology, Sydney, Broadway NSW, Australia
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Ghiaroni V, Sasaki M, Fuwa H, Rossini GP, Scalera G, Yasumoto T, Pietra P, Bigiani A. Inhibition of Voltage-Gated Potassium Currents by Gambierol in Mouse Taste Cells. Toxicol Sci 2005; 85:657-65. [PMID: 15689421 DOI: 10.1093/toxsci/kfi097] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ciguatera is a food poisoning caused by toxins of Gambierdiscus toxicus, a marine dinoflagellate. The neurological features of this intoxication include sensory abnormalities, such as paraesthesia, heightened nociperception, and also taste alterations. Here, we have evaluated the effect of gambierol, one of the possible ciguatera toxins, on the voltage-gated ion currents in taste cells. Taste cells are excitable cells endowed with voltage-gated Na+, K+, and Cl- currents (I(Na), I(K), and I(Cl), respectively). By applying the patch-clamp technique to single cells in isolated taste buds obtained from the mouse vallate papilla, we have recorded such currents and determined the effect of bath-applied gambierol. We found that this toxin markedly inhibited I(K) in the nanomolar range (IC50 of 1.8 nM), whereas it showed no significant effect on I(Na) or I(Cl) even at high concentration (1 microM). The block of I(K) was irreversible even after a 50-min wash. In addition to affecting the current amplitude, we found that gambierol significantly altered both the activation and inactivation processes of I(K). In conclusion, unlike other toxins involved in ciguatera, such as ciguatoxins, which affect the functioning of voltage-gated sodium channels, the preferred molecular target of gambierol is the voltage-gated potassium channel, at least in taste cells. Voltage-gated potassium currents play an important role in the generation of the firing pattern during chemotransduction. Thus, gambierol may alter action potential discharge in taste cells and this could be associated with the taste alterations reported in the clinical literature.
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Affiliation(s)
- Valeria Ghiaroni
- Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, 41100 Modena, Italy
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Yamaoka K, Inoue M, Miyahara H, Miyazaki K, Hirama M. A quantitative and comparative study of the effects of a synthetic ciguatoxin CTX3C on the kinetic properties of voltage-dependent sodium channels. Br J Pharmacol 2004; 142:879-89. [PMID: 15197105 PMCID: PMC1575065 DOI: 10.1038/sj.bjp.0705852] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Ciguatoxins (CTXs) are known to bind to receptor site 5 of the voltage-dependent Na channel, but the toxin's physiological effects are poorly understood. In this study, we investigated the effects of a ciguatoxin congener (CTX3C) on three different Na-channel isoforms, rNa(v)1.2, rNa(v)1.4, and rNa(v)1.5, which were transiently expressed in HEK293 cells. The toxin (1.0 micromol l(-1)) shifted the activation potential (V(1/2) of activation curve) in the negative direction by 4-9 mV and increased the slope factor (k) from 8 mV to between 9 and 12 mV (indicative of decreased steepness of the activation curve), thereby resulting in a hyperpolarizing shift of the threshold potential by 30 mV for all Na channel isoforms. The toxin (1.0 micromol l(-1)) significantly accelerated the time-to-peak current from 0.62 to 0.52 ms in isoform rNa(v)1.2. Higher doses of the toxin (3-10 micromol l(-1)) additionally decreased time-to-peak current in rNa(v)1.4 and rNa(v)1.5. A toxin effect on decay of I(Na) at -20 mV was either absent or marginal even at relatively high doses of CTX3C. The toxin (1 micromol l(-1)) shifted the inactivation potential (V(1/2) of inactivation curve) in the negative direction by 15-18 mV in all isoforms. I(Na) maxima of the I-V curve (at -20 mV) were suppressed by application of 1.0 micromol l(-1) CTX3C to a similar extent (80-85% of the control) in all the three isoforms. Higher doses of CTX3C up to 10 micromol l(-1) further suppressed I(Na) to 61-72% of the control. Recovery from slow inactivation induced by a depolarizing prepulse of intermediate duration (500 ms) was dramatically delayed in the presence of 1.0 micromol l(-1) CTX3C, as time constants describing the monoexponential recovery were increased from 38+/-8 to 588+/-151 ms (n=5), 53+/-6 to 338+/-85 ms (n=4), and 23+/-3 to 232+/-117 ms (n=3) in rNa(v)1.2, rNa(v)1.4, and rNa(v)1.5, respectively. CTX3C exerted multimodal effects on sodium channels, with simultaneous stimulatory and inhibitory aspects, probably due to the large molecular size (3 nm in length) and lipophilicity of this membrane-spanning toxin.
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Affiliation(s)
- Kaoru Yamaoka
- Department of Physiology, School of Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8551, Japan.
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Hidalgo J, Liberona JL, Molgó J, Jaimovich E. Pacific ciguatoxin-1b effect over Na+ and K+ currents, inositol 1,4,5-triphosphate content and intracellular Ca2+ signals in cultured rat myotubes. Br J Pharmacol 2002; 137:1055-62. [PMID: 12429578 PMCID: PMC1573594 DOI: 10.1038/sj.bjp.0704980] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. The action of the main ciguatoxin involved in ciguatera fish poisoning in the Pacific region (P-CTX-1b) was studied in myotubes originated from rat skeletal muscle cells kept in primary culture. 2. The effect of P-CTX-1b on sodium currents at short times of exposure (up to 1 min) showed a moderate increase in peak Na+ current. During prolonged exposures, P-CTX-1b decreased the peak Na+ current. This action was always accompanied by an increase of leakage currents, tail currents and outward Na+ currents, resulting in an intracellular Na+ accumulation. This effect is blocked by prior exposure to tetrodotoxin (TTX) and becomes evident only after washout of TTX. 3. Low to moderate concentrations of P-CTX-1b (2-5 nM) partially blocked potassium currents in a manner that was dependent on the membrane potential. 4. P-CTX-1b (2-12 nM) caused a small membrane depolarization (3-5 mV) and an increase in the frequency of spontaneous action potential discharges that reached in general low frequencies (0.1-0.5 Hz). 5. P-CTX-1b (10 nM) caused a transient increase of intracellular inositol 1,4,5-trisphosphate (IP(3)) mass levels, which was blocked by TTX. 6. In the presence of P-CTX-1b (10 nM) and in the absence of external Ca2+, the intracellular Ca2+ levels show a transient increase in the cytoplasm as well as in the nuclei. The time course of this effect may reflect the action of IP(3) over internal stores activated by P-CTX-1b-induced membrane depolarization.
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Affiliation(s)
- Jorge Hidalgo
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile.
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Hogg RC, Lewis RJ, Adams DJ. Ciguatoxin-induced oscillations in membrane potential and action potential firing in rat parasympathetic neurons. Eur J Neurosci 2002; 16:242-8. [PMID: 12169106 DOI: 10.1046/j.1460-9568.2002.02071.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The actions of ciguatoxins from the Pacific (P-CTX-1) and Caribbean (C-CTX-1) regions were investigated in isolated parasympathetic neurons from rat intracardiac ganglia using patch-clamp recording techniques. Under current-clamp conditions, bath application of P-CTX-1 (1-10 nm) or C-CTX-1 (10-30 nm) caused a gradual depolarization that was accompanied by oscillation of the membrane potential leading to tonic action potential firing. Membrane potential oscillations were observed between -45 and -60 mV and had an amplitude of 10-20 mV and a mean frequency of 10 Hz. Oscillation frequency was temperature-dependent with a Q10 of 2.0. Membrane oscillations were temporarily inhibited by hyperpolarizing current pulses and potentiated by weak depolarizing current pulses. The amplitude of oscillations was reduced upon lowering the external Na+ concentration and inhibited by tetrodotoxin (TTX), tetracaine or Zn2+. Tetraethylammonium, 4-aminopyridine, Cs+, Cd2+, Ba2+, 1,4,4'-diothiocyanato-2,2'-stilbenedisulphonic acid (DIDS) and ouabain had no effect on the CTX-1-induced membrane depolarization and oscillations. Brevetoxin (PbTx-3, 100 nm), in contrast to CTX-1, caused a membrane depolarization that was not associated with oscillation of the membrane potential. Under voltage-clamp conditions, P-CTX-1 inhibited the peak amplitude of the voltage-dependent Na+ current and shifted the activation curve to more negative potentials, but membrane oscillations were not seen in this configuration. These results suggest that ciguatoxins cause oscillation of the membrane potential in mammalian autonomic neurons by modifying the activation and inactivation properties of a population of TTX-sensitive Na+ channels.
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Affiliation(s)
- R C Hogg
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072 Australia
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23
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Benoit E, Gordon D. The scorpion α-like toxin Lqh III specifically alters sodium channel inactivation in frog myelinated axons. Neuroscience 2001; 104:551-9. [PMID: 11377854 DOI: 10.1016/s0306-4522(01)00073-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The effects of 1-100 nM Lqh III, an alpha-like toxin isolated from the scorpion Leiurus quinquestriatus hebraeus, were assessed on the nodal membrane potential and ionic currents of single frog myelinated axons. In current-clamped axons, Lqh III increased the duration of action potentials without markedly affecting the peak amplitude and the resting membrane potential. The toxin was less effective when the resting membrane potential of axons was increasingly more positive. The Lqh III-induced increase in action potential duration was not due to the blockade of K(+) channels, since the toxin had no significant effect upon the K(+) current. In contrast, Lqh III inhibited the inactivation of a fraction of the Na(+) current, leading to a maintained late inward Na(+) current which represented about 45% of the peak Na(+) current, as observed during long-lasting depolarisations and in steady-state Na(+) current inactivation-voltage relationships when the pre-pulse potential was more positive than about -30mV. The activation kinetics of the late Na(+) current were well described by a single exponential whose time constant was 8.53+/-0.78 ms (n=3). Finally, Lqh III slowed the time-course of the remaining peak Na(+) current inactivation by altering initial amplitudes (to time zero of depolarisation) and time constants of its fast and slow phases. No significant additional effect was detected during the action of the toxin. In conclusion, we propose that, in frog myelinated axons, the effects of Lqh III are those typically attributed to classical scorpion alpha-toxins.
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Affiliation(s)
- E Benoit
- Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie Cellulaire et Moléculaire, UPR 9040, CNRS, bât. 32, F-91198 cedex, Gif sur Yvette, France.
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Abstract
Ciguatera is a global disease caused by the consumption of certain warm-water fish (ciguateric fish) that have accumulated orally effective levels of sodium channel activator toxins (ciguatoxins) through the marine food chain. Symptoms of ciguatera include a range of gastrointestinal, neurological and cardiovascular disturbances. This review examines progress in our understanding of ciguatera from the work of Banner in the late 1950s to the present. Similarities and differences in ciguatera in the Pacific Ocean, Indian Ocean and Caribbean Sea are highlighted, and future research directions are suggested.
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Affiliation(s)
- R J Lewis
- Queensland Agricultural Biotechnology Centre (DPI), Gehrmann Laboratories, The University of Queensland, Qld 4072, Australia.
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Abstract
The authors divide biological toxins into animal, plant, and bacterial classes and discuss each within a context of demographic, clinical and research examples. Advances in our knowledge are highlighted, and the authors relate the implications of this knowledge to target-specific neurologic involvement.
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Affiliation(s)
- C G Goetz
- Department of Neurological Sciences, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Il 60612, USA
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Mattei C, Molgó J, Marquais M, Vernoux J, Benoit E. Hyperosmolar D-mannitol reverses the increased membrane excitability and the nodal swelling caused by Caribbean ciguatoxin-1 in single frog myelinated axons. Brain Res 1999; 847:50-8. [PMID: 10564735 DOI: 10.1016/s0006-8993(99)02032-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The effects of hyperosmolar D-mannitol were studied on single frog myelinated nerve fibres previously poisoned with Caribbean ciguatoxin-1 (C-CTX-1), a new toxin isolated from the pelagic fish Caranx latus inhabiting the Caribbean region. In current-clamped myelinated axons, C-CTX-1 (50-120 nM) caused spontaneous and repetitive action potential discharges after a short delay. In addition, the toxin produced a marked swelling of nodes of Ranvier of myelinated axons that reached a steady state within about 90 min, as revealed by using confocal laser scanning microscopy. The increased excitability and the nodal swelling caused by C-CTX-1 were prevented or reversed by an external hyperosmotic solution containing 100 mM D-mannitol. Moreover, the C-CTX-1-induced nodal swelling was completely prevented by the blockade of voltage-sensitive sodium channels by tetrodotoxin (TTX). It is suggested that C-CTX-1, by increasing nerve membrane excitability, enhances Na(+) entry into nodes of Ranvier through TTX-sensitive sodium channels, which directly or indirectly disturb the osmotic equilibrium between intra- and extra-axonal media resulting in an influx of water that was responsible for the long-lasting nodal swelling. The fact, that hyperosmolar D-mannitol either reversed or prevented the neurocellular actions of C-CTX-1, is of particular interest since it provides the rational basis for its use to treat the neurological symptoms of ciguatera fish poisoning in the Caribbean area.
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Affiliation(s)
- C Mattei
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, UPR 9040, CNRS, bât. 32, 1 Avenue de la Terrasse, Gif sur Yvette, France
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Le Gall F, Favreau P, Benoit E, Mattei C, Bouet F, Menou JL, Ménez A, Letourneux Y, Molgó J. A new conotoxin isolated from Conus consors venom acting selectively on axons and motor nerve terminals through a Na+-dependent mechanism. Eur J Neurosci 1999; 11:3134-42. [PMID: 10510177 DOI: 10.1046/j.1460-9568.1999.00732.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A novel conotoxin was isolated and characterized from the venom of the fish-hunting marine snail Conus consors. The peptide was identified by screening chromatography fractions of the crude venom that produced a marked contraction and extension of the caudal and dorsal fins in fish, and noticeable spontaneous contractions of isolated frog neuromuscular preparations. The peptide, named CcTX, had 30 amino acids and the following scaffold: X11CCX7CX2CXCX3C. At the frog neuromuscular junction, CcTx at nanomolar concentrations selectively increased nerve terminal excitability so that a single nerve stimulation triggered trains of repetitive or spontaneous synaptic potentials and action potentials. In contrast, CcTx had no noticeable effect on muscle excitability even at concentrations 100 x higher than those that affected motor nerve terminals, as revealed by direct muscle stimulation. In addition, CcTx increased miniature endplate potential (MEPP) frequency in a Ca2+-free medium supplemented with ethylene glycol-bis-(beta-aminoethyl ether)-N,N,N', N'-tetraacetic acid (EGTA). Blockade of voltage-dependent sodium channels with tetrodotoxin (TTX) either prevented or suppressed the increase of MEPP frequency induced by the toxin. CcTx also produced a TTX-sensitive depolarization of the nodal membrane in single myelinated axons giving rise, in some cases, to repetitive and/or spontaneous action potential discharges. In addition, CcTx increased the nodal volume of myelinated axons, as determined using confocal laser scanning microscopy. This increase was reversed by external hyperosmolar solutions and was prevented by pretreatment of axons with TTX. It is suggested that CcTx, by specifically activating neuronal voltage-gated sodium channels at the resting membrane potential, produced Na+ entry into nerve terminals and axons without directly affecting skeletal muscle fibres. CcTx belongs to a novel family of conotoxins that targets neuronal voltage-gated sodium channels.
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Affiliation(s)
- F Le Gall
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, UPR 9040, Centre National de la Recherche Scientifique, Gif sur Yvette, France
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Mattei C, Dechraoui MY, Molgó J, Meunier FA, Legrand AM, Benoit E. Neurotoxins targetting receptor site 5 of voltage-dependent sodium channels increase the nodal volume of myelinated axons. J Neurosci Res 1999; 55:666-73. [PMID: 10220108 DOI: 10.1002/(sici)1097-4547(19990315)55:6<666::aid-jnr2>3.0.co;2-h] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effects of a C57 type ciguatoxin (CTX-3C) and two types of brevetoxins (PbTx-1 and PbTx-3), known to bind to receptor site 5 of the neuronal voltage-dependent Na+ channel-protein, were studied on the morphology of living frog myelinated axons using confocal laser scanning microscopy. During the action of CTX-3C, PbTx-1, and PbTx-3 (10-50 nM), a marked swelling of nodes of Ranvier was observed without apparent modification of internodal parts of axons. In all cases, toxin-induced nodal swelling attained a steady-state within 75-100 min that was well maintained during an additional 90-115 min. The nodal swelling was reversed by an external hyperosmotic solution containing 100 mM D-mannitol and could be completely prevented by blocking voltage-dependent Na+ channels with 1 microM tetrodotoxin. It is suggested that CTX-3C, PbTx-1, and PbTx-3 by activating Na+ channels cause a continuous Na+ entry into axons, increasing internal Na+ concentration. Such an increase directly or indirectly disturbs the osmotic equilibrium between intra- and extra-axonal media, resulting in an influx of water, which is responsible for the long-lasting nodal swelling. Similar results were previously reported with two C60 type ciguatoxins (CTX-1B and CTX-4B). Thus, it is concluded that the four types of toxins targetting receptor site 5 of neuronal voltage-dependent Na+ channels, not only enhance nerve membrane excitability but also, on a long-term basis, cause a marked increase in the axonal volume.
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Affiliation(s)
- C Mattei
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, Gif sur Yvette, France
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