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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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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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Mullins ME, Hoffman RS. Is mannitol the treatment of choice for patients with ciguatera fish poisoning? Clin Toxicol (Phila) 2017; 55:947-955. [DOI: 10.1080/15563650.2017.1327664] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Michael E. Mullins
- Division of Emergency Medicine, Washington University School of Medicine, Saint Louis, MO, USA
| | - Robert S. Hoffman
- Division of Medical Toxicology, Ronald O. Perelman Department of Emergency Medicine, New York University School of Medicine, New York, NY, USA
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An Updated Review of Ciguatera Fish Poisoning: Clinical, Epidemiological, Environmental, and Public Health Management. Mar Drugs 2017; 15:md15030072. [PMID: 28335428 PMCID: PMC5367029 DOI: 10.3390/md15030072] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/13/2017] [Accepted: 02/13/2017] [Indexed: 01/07/2023] Open
Abstract
Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world. It causes substantial human health, social, and economic impacts. The illness produces a complex array of gastrointestinal, neurological and neuropsychological, and cardiovascular symptoms, which may last days, weeks, or months. This paper is a general review of CFP including the human health effects of exposure to ciguatoxins (CTXs), diagnosis, human pathophysiology of CFP, treatment, detection of CTXs in fish, epidemiology of the illness, global dimensions, prevention, future directions, and recommendations for clinicians and patients. It updates and expands upon the previous review of CFP published by Friedman et al. (2008) and addresses new insights and relevant emerging global themes such as climate and environmental change, international market issues, and socioeconomic impacts of CFP. It also provides a proposed universal case definition for CFP designed to account for the variability in symptom presentation across different geographic regions. Information that is important but unchanged since the previous review has been reiterated. This article is intended for a broad audience, including resource and fishery managers, commercial and recreational fishers, public health officials, medical professionals, and other interested parties.
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Sintunawa C, Wacharapluesadee S, Saraya A, Hemachudha T. Surveillance of marine fish for ciguatera toxin at fish markets in Bangkok, Thailand. ASIAN BIOMED 2017. [DOI: 10.5372/1905-7415.0802.288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abstract
Background: Ciguatera intoxication is a form of food poisoning. It is caused by the consumption of certain warm-water fish that have accumulated ciguatera toxin (CTX) through the marine food chain. Ciguatera fish poisoning (CFP) is a global disease, which although common, has been largely ignored in Thailand. This may be attributed to lack of confirmatory tests and seemingly nonspecific clinical presentations.
Objective: We studied CTX contamination in marine fish sold at Bangkok markets.
Methods: A surveillance of CTX in fish using the Cigua-Check assay has been conducted in Bangkok, the center of seafood marketing in Thailand. Here, there are several types of fish. Some come from domestic fishing and others are imported from Indonesia, Myanmar, or India.
Results: A random survey at three fish markets in Bangkok revealed two samples possibly contaminated with ciguatera toxin from a total 227 fish samples (of 21 fish species). This is the first report of finding CTX contamination in fish meat sold in Bangkok.
Conclusion: It is possible that these CTX-positive fish were caught from other countries. Even though the positivity (0.88%) is lower when compared with studies of other endemic areas (5.0% in Hawaii and Pacific Islands), this finding should raise awareness of the possibility of facing rare CFP intoxication from fish obtained at local Thai markets.
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Affiliation(s)
- Chirapol Sintunawa
- Faculty of Environment and Resource Studies, Mahidol University, Nakorn Pathom 73170, Thailand
| | - Supaporn Wacharapluesadee
- Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, and WHO Collaborating Centre for Research and Training on Viral Zoonoses, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Abhinbhen Saraya
- Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, and WHO Collaborating Centre for Research and Training on Viral Zoonoses, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Thiravat Hemachudha
- Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, and WHO Collaborating Centre for Research and Training on Viral Zoonoses, Thai Red Cross Society, Bangkok 10330, Thailand
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Jovanovic ZD, Stanojevic MB, Nedeljkov VB. The neurotoxic effects of hydrogen peroxide and copper in Retzius nerve cells of the leech Haemopis sanguisuga. Biol Open 2016; 5:381-8. [PMID: 26935393 PMCID: PMC4890660 DOI: 10.1242/bio.014936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Oxidative stress and the generation of reactive oxygen species (ROS) play an important role in cellular damage. Electrophysiological analyses have shown that membrane transport proteins are susceptible to ROS. In the present study, oxidative stress was induced in Retzius nerve cells of the leechHaemopis sanguisugaby bath application of 1 mM of hydrogen peroxide (H2O2) and 0.02 mM of copper (Cu) for 20 min. The H2O2/Cu(II) produced considerable changes in the electrical properties of the Retzius nerve cells. Intracellular recording of the resting membrane potential revealed that the neuronal membrane was depolarized in the presence of H2O2/Cu(II). We found that the amplitude of action potentials decreased, while the duration augmented in a progressive way along the drug exposure time. The combined application of H2O2and Cu(II) caused an initial excitation followed by depression of the spontaneous electrical activity. Voltage-clamp recordings revealed a second effect of the oxidant, a powerful inhibition of the outward potassium channels responsible for the repolarization of action potentials. The neurotoxic effect of H2O2/Cu(II) on the spontaneous spike electrogenesis and outward K(+)current of Retzius nerve cells was reduced in the presence of hydroxyl radical scavengers, dimethylthiourea and dimethyl sulfoxide, but not mannitol. This study provides evidence for the oxidative modification of outward potassium channels in Retzius nerve cells. The oxidative mechanism of the H2O2/Cu(II) system action on the electrical properties of Retzius neurons proposed in this study might have a wider significance, referring not only to leeches but also to mammalian neurons.
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Affiliation(s)
- Zorica D Jovanovic
- Department of Pathological Physiology, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia
| | - Marija B Stanojevic
- Institute for Pathological Physiology, School of Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Vladimir B Nedeljkov
- Institute for Pathological Physiology, School of Medicine, University of Belgrade, 11000 Belgrade, Serbia
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Bertrand H, Kyriazis M, Reeves KD, Lyftogt J, Rabago D. Topical Mannitol Reduces Capsaicin-Induced Pain: Results of a Pilot-Level, Double-Blind, Randomized Controlled Trial. PM R 2015; 7:1111-1117. [PMID: 25978942 DOI: 10.1016/j.pmrj.2015.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 05/01/2015] [Accepted: 05/02/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Capsaicin specifically activates, and then gradually exhausts, the transient receptor potential vanilloid type 1 (TRPV1) receptor, a key receptor in neuropathic pain. Activation of the TRPV-1 receptor is accompanied by burning pain. A natural substance or medication that can reduce the burning pain resulting from capsaicin application may have therapeutic potential in neuropathic pain. OBJECTIVE To assess the pain-relieving effects of a mannitol-containing cream in a capsaicin-based pain model. DESIGN Randomized, placebo-controlled, double-blind clinical trial. SETTING Outpatient pain clinic. PARTICIPANTS Twenty-five adults with pain-free lips. METHODS Capsaicin .075% cream was applied to both halves of each participant's upper lip, inducing pain via stimulation of the transient receptor potential vanilloid 1 (TRPV1, capsaicin) receptor, then removed after 5 minutes or when participants reported a burning pain of 8/10, whichever came first. A cream containing mannitol and the same cream without mannitol (control) were then immediately applied, 1 on each side of the lip, in an allocation-masked manner. OUTCOME MEASURES Participants self-recorded a numeric rating scale (NRS, 0-10) pain score for each side of the lip per minute for 10 minutes. A t-test was performed to evaluate the pain score change from baseline between each side of the lip at each recording. Area under the curve (AUC) analysis was used to determine the overall difference between groups. RESULTS Participants reached a capsaicin-induced pain level of 7.8 ± 1.0 points in 3.3 ± 1.6 minutes that was equal on both sides of the lip. Both groups reported progressive diminution of pain over the 10-minute study period. However, participants reported significantly reduced pain scores on the mannitol cream half-lip compared to control at 3 through 10 minutes (P < .05) and in AUC analysis (P < .001). CONCLUSIONS Mannitol cream reduced self-reported pain scores in a capsaicin pain model more rapidly than a control cream, potentially via a TRPV1 receptor effect.
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Affiliation(s)
| | - Marylene Kyriazis
- University of British Columbia, Faculty of Pharmaceutical Sciences, North Vancouver, BC, Canada
| | - K Dean Reeves
- Department of Physical Medicine and Rehabilitation, University of Kansas, Kansas City, KS
| | - John Lyftogt
- Private Practice Sports Medicine, retired, Cass Bass, Lyttelton, New Zealand
| | - David Rabago
- Department of Family Medicine, University of Wisconsin, Madison, WI
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Saraya A, Sintunawa C, Wacharapluesadee S, Swangpun K, Dumrongchua S, Wilde H, Hemachudha T. Marine Fish Toxins in Thailand: Report of 6 Suspected Ciguatera Cases. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/crcm.2014.35065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Balaji SN, Trivedi V. Extracellular methemoglobin primes red blood cell aggregation in malaria: an in vitro mechanistic study. FEBS Lett 2013; 587:350-7. [PMID: 23313944 DOI: 10.1016/j.febslet.2012.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 12/02/2012] [Accepted: 12/17/2012] [Indexed: 11/28/2022]
Abstract
Toxic byproducts from infected RBC cause rheological alteration and RBC aggregation. Malaria culture supernatant has the ability to exhibit RBC aggregation. Ammonium sulfate fractionation and immunodepletion of methemoglobin from culture supernatant confirms methemoglobin as a major aggregant. In vitro treatment of RBC with methemoglobin induces irreversible high order RBC aggregates, resistant to shear stress and physical forces. Methemoglobin-mediated ROS generation in the external micro-environment to develop oxidative stress close to RBC membrane seems to be responsible for initiating and forming high order RBC aggregates through phosphatidyl-serine externalization. Removal of oxidative stress through antioxidant treatment abolishes high order RBC aggregate formation. In conclusion, we discovered a novel pathway of methemoglobin-mediated RBC aggregation and its potential role in patho-physiological effects during malaria.
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Affiliation(s)
- S N Balaji
- Malaria Research Group, Department of Biotechnology, Indian Institute of Technology-Guwahati, Guwahati 781039, Assam, India
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Kumar-Roiné S, Taiana Darius H, Matsui M, Fabre N, Haddad M, Chinain M, Pauillac S, Laurent D. A review of traditional remedies of ciguatera fish poisoning in the Pacific. Phytother Res 2012; 25:947-58. [PMID: 21287650 DOI: 10.1002/ptr.3396] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Ciguatera fish poisoning (CFP) is an illness caused by eating tropical coral fish contaminated with ciguatoxins (CTXs). The clinical management of patients with CFP is generally supportive and symptomatic in nature as no antidote exists. Of the many drugs prescribed, several have been claimed to be efficient in small, uncontrolled studies, but the outcomes of treatments with these medicines are often contradictory. In New Caledonia, traditional remedies are commonly employed in the treatment of CFP and of the 90 plant species catalogued as useful in CFP, the most popular herbal remedy by far is a decoction prepared from the leaves of Heliotropium foertherianum Diane & Hilger (Boraginaceae). Other important plants used in the treatment of CFP include Euphorbia hirta L. (Euphorbiaceae) and Vitex L. sp. (Lamiaceae). This review focuses on the evidence for efficacy of these species and pharmacological studies which support their use. Other plants used in CFP and the conventional treatment of CFP are also discussed briefly.
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Affiliation(s)
- Shilpa Kumar-Roiné
- UMR 152-Laboratoire de Pharmacochimie des Substances Naturelles et Pharmacophores Redox, Université de Toulouse, UPS, 118 Rte de Narbonne, F-31062 Toulouse Cedex 9, 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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Yamaji N, Little MJ, Nishio H, Billen B, Villegas E, Nishiuchi Y, Tytgat J, Nicholson GM, Corzo G. Synthesis, solution structure, and phylum selectivity of a spider delta-toxin that slows inactivation of specific voltage-gated sodium channel subtypes. J Biol Chem 2009; 284:24568-82. [PMID: 19592486 DOI: 10.1074/jbc.m109.030841] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Magi 4, now renamed delta-hexatoxin-Mg1a, is a 43-residue neurotoxic peptide from the venom of the hexathelid Japanese funnel-web spider (Macrothele gigas) with homology to delta-hexatoxins from Australian funnel-web spiders. It binds with high affinity to receptor site 3 on insect voltage-gated sodium (Na(V)) channels but, unlike delta-hexatoxins, does not compete for the related site 3 in rat brain despite being previously shown to be lethal by intracranial injection. To elucidate differences in Na(V) channel selectivity, we have undertaken the first characterization of a peptide toxin on a broad range of mammalian and insect Na(V) channel subtypes showing that delta-hexatoxin-Mg1a selectively slows channel inactivation of mammalian Na(V)1.1, Na(V)1.3, and Na(V)1.6 but more importantly shows higher affinity for insect Na(V)1 (para) channels. Consequently, delta-hexatoxin-Mg1a induces tonic repetitive firing of nerve impulses in insect neurons accompanied by plateau potentials. In addition, we have chemically synthesized and folded delta-hexatoxin-Mg1a, ascertained the bonding pattern of the four disulfides, and determined its three-dimensional solution structure using NMR spectroscopy. Despite modest sequence homology, we show that key residues important for the activity of scorpion alpha-toxins and delta-hexatoxins are distributed in a topologically similar manner in delta-hexatoxin-Mg1a. However, subtle differences in the toxin surfaces are important for the novel selectivity of delta-hexatoxin-Mg1a for certain mammalian and insect Na(V) channel subtypes. As such, delta-hexatoxin-Mg1a provides us with a specific tool with which to study channel structure and function and determinants for phylum- and tissue-specific activity.
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Affiliation(s)
- Nahoko Yamaji
- Suntory Institute for Bioorganic Research, Mishima-gun, Shimamoto-cho, Osaka 618-8503, Japan
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Dyavanapalli J, Rimmer K, Harper AA. The action of high K+ and aglycaemia on the electrical properties and synaptic transmission in rat intracardiac ganglion neurones in vitro. Exp Physiol 2008; 94:201-12. [PMID: 18978036 PMCID: PMC2713859 DOI: 10.1113/expphysiol.2008.044784] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have investigated the action of two elements of acute ischaemia, high potassium and aglycaemia, on the electrophysiological properties and ganglionic transmission of adult rat intracardiac ganglion (ICG) neurones. We used a whole-mount ganglion preparation of the right atrial ganglion plexus and sharp microelectrode recording techniques. Increasing extracellular K+ from its normal value of 4.7 mm to 10 mm decreased membrane potential and action potential after-hyperpolarization amplitude but otherwise had no effect on postganglionic membrane properties. It did, however, reduce the ability of synaptically evoked action potentials to follow high-frequency (100 Hz) repetitive stimulation. A further increase in K+ changed both the passive and the active membrane properties of the postganglionic neurone: time constant, membrane resistance and action potential overshoot were all decreased in high K+ (20 mm). The ICG neurones display a predominantly phasic discharge in response to prolonged depolarizing current pulses. High K+ had no impact on this behaviour but reduced the time-dependent rectification response to hyperpolarizing currents. At 20 mm, K+ practically blocked ganglionic transmission in most neurones at all frequencies tested. Aglycaemia, nominally glucose-free physiological saline solution (PSS), increased the time constant and membrane resistance of ICG neurones but otherwise had no action on their passive or active properties or ganglionic transmission. However, the combination of aglycaemia and 20 mm K+ displayed an improvement in passive properties and ganglionic transmission when compared with 20 mm K+ PSS. These data indicate that the presynaptic terminal is the primary target of high extracellular potassium and that aglycaemia may have protective actions against this challenge.
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Friedman MA, Fleming LE, Fernandez M, Bienfang P, Schrank K, Dickey R, Bottein MY, Backer L, Ayyar R, Weisman R, Watkins S, Granade R, Reich A. Ciguatera fish poisoning: treatment, prevention and management. Mar Drugs 2008; 6:456-79. [PMID: 19005579 PMCID: PMC2579736 DOI: 10.3390/md20080022] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 07/24/2008] [Accepted: 08/19/2008] [Indexed: 11/17/2022] Open
Abstract
Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world, and it causes substantial physical and functional impact. It produces a myriad of gastrointestinal, neurologic and/or cardiovascular symptoms which last days to weeks, or even months. Although there are reports of symptom amelioration with some interventions (e.g. IV mannitol), the appropriate treatment for CFP remains unclear to many physicians. We review the literature on the treatments for CFP, including randomized controlled studies and anecdotal reports. The article is intended to clarify treatment options, and provide information about management and prevention of CFP, for emergency room physicians, poison control information providers, other health care providers, and patients.
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Gunning SJ, Maggio F, Windley MJ, Valenzuela SM, King GF, Nicholson GM. The Janus-faced atracotoxins are specific blockers of invertebrate K(Ca) channels. FEBS J 2008; 275:4045-59. [PMID: 18625007 DOI: 10.1111/j.1742-4658.2008.06545.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Janus-faced atracotoxins are a unique family of excitatory peptide toxins that contain a rare vicinal disulfide bridge. Although lethal to a wide range of invertebrates, their molecular target has remained enigmatic for almost a decade. We demonstrate here that these toxins are selective, high-affinity blockers of invertebrate Ca(2+)-activated K(+) (K(Ca)) channels. Janus-faced atracotoxin (J-ACTX)-Hv1c, the prototypic member of this toxin family, selectively blocked K(Ca) channels in cockroach unpaired dorsal median neurons with an IC(50) of 2 nm, but it did not significantly affect a wide range of other voltage-activated K(+), Ca(2+) or Na(+) channel subtypes. J-ACTX-Hv1c blocked heterologously expressed cockroach large-conductance Ca(2+)-activated K(+) (pSlo) channels without a significant shift in the voltage dependence of activation. However, the block was voltage-dependent, indicating that the toxin probably acts as a pore blocker rather than a gating modifier. The molecular basis of the insect selectivity of J-ACTX-Hv1c was established by its failure to significantly inhibit mouse mSlo currents (IC(50) approximately 10 mum) and its lack of activity on rat dorsal root ganglion neuron K(Ca) channel currents. This study establishes the Janus-faced atracotoxins as valuable tools for the study of invertebrate K(Ca) channels and suggests that K(Ca) channels might be potential insecticide targets.
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Affiliation(s)
- Simon J Gunning
- Neurotoxin Research Group, Department of Medical & Molecular Biosciences, University of Technology, Sydney, NSW, Australia
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An odd pilgrim in the Holy Land. Am J Emerg Med 2008; 26:383.e3-6. [DOI: 10.1016/j.ajem.2007.05.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 05/26/2007] [Indexed: 11/18/2022] Open
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Abstract
Food poisoning is encountered throughout the world. Many of the toxins responsible for specific food poisoning syndromes are no longer limited to isolated geographic locations. With increased travel and the ease of transporting food products, it is likely that a patient may present to any emergency department with the clinical effects of food poisoning. Recognizing specific food poisoning syndromes allows emergency health care providers not only to initiate appropriate treatment rapidly but also to notify health departments early and thereby prevent further poisoning cases. This article reviews several potential food-borne poisons and describes each agent's mechanism of toxicity, expected clinical presentation, and currently accepted treatment.
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Affiliation(s)
- David T Lawrence
- Blue Ridge Poison Center, Division of Medical Toxicology, Department of Emergency Medicine, University of Virginia, Charlottesville, VA 22908-0774, USA
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