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Wassel MA, Makabe-Kobayashi Y, Iqbal MM, Takatani T, Sakakura Y, Hamasaki K. The impact of tetrodotoxin (TTX) on the gut microbiome in juvenile tiger pufferfish, Takifugu rubripes. Sci Rep 2024; 14:16684. [PMID: 39085277 PMCID: PMC11291987 DOI: 10.1038/s41598-024-66112-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 06/27/2024] [Indexed: 08/02/2024] Open
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin that accumulates in Takifugu rubripes, commonly known as pufferfish, through the ingestion of TTX-bearing organisms as part of their food chain. Although researchers believe that pufferfish use TTX to relieve stress, data are not currently available on how TTX affects the gut microbiota of pufferfish. To address this gap, our study aimed to investigate whether administering TTX to fish could alter their gut microbiota and overall health under various salinity conditions, including 30.0 ppt, 8.5 ppt, and 1.7 ppt salinity, which represent full-strength, isosmotic, and low-salinity stress, respectively. We analyzed the effect of TTX ingestion on the community structure, core microbiome, and metabolic capabilities of the gut microbiome using high-throughput sequencing technologies. The predominant bacterial taxa within the gut microbiome were Firmicutes (21-85%), Campilobacterota (2.8-67%), Spirochaetota (0.5-14%), and Proteobacteria (0.7-9.8%), with Mycoplasma, uncultured Arcobacteraceae, Brevinema, Vibrio, Rubritalea, and uncultured Pirellulaceae as core genera. Our findings indicated that the impact of TTX on high-abundance genera at 30.0 ppt and 8.5 ppt salinity levels was negligible, indicating their stability and resilience to TTX ingestion. However, at 1.7 ppt, TTX-fed fish showed a significant increase in uncultured Arcobacteraceae. Furthermore, our analysis of TTX-fed fish revealed taxonomic alterations in low-abundance taxa, which altered the predicted functions of the gut microbiota at all salinity levels. These results suggest that TTX administration could cause subtle effects on the metabolic functions of gut microbial communities. Overall, our study provides insights into the complex relationship between a TTX-accumulating animal, T. rubripes, and its gut microbiota.
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Affiliation(s)
- Mai A Wassel
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
- Genetics and Genetic Engineering Research Group, National Institute of Oceanography and Fisheries, NIOF, Cairo, Egypt.
| | - Yoko Makabe-Kobayashi
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
| | - Md Mehedi Iqbal
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
| | - Tomohiro Takatani
- Graduate School of Integrated Science and Technology, Nagasaki University, 1‑14 Bunkyo, Nagasaki, 852‑8521, Japan
| | - Yoshitaka Sakakura
- Graduate School of Integrated Science and Technology, Nagasaki University, 1‑14 Bunkyo, Nagasaki, 852‑8521, Japan
| | - Koji Hamasaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan.
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2
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Pukkanasut P, Jaskula-Sztul R, Gomora JC, Velu SE. Therapeutic targeting of voltage-gated sodium channel Na V1.7 for cancer metastasis. Front Pharmacol 2024; 15:1416705. [PMID: 39045054 PMCID: PMC11263763 DOI: 10.3389/fphar.2024.1416705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 06/12/2024] [Indexed: 07/25/2024] Open
Abstract
This review focuses on the expression and function of voltage-gated sodium channel subtype NaV1.7 in various cancers and explores its impact on the metastasis driving cell functions such as proliferation, migration, and invasiveness. An overview of its structural characteristics, drug binding sites, inhibitors and their likely mechanisms of action are presented. Despite the lack of clarity on the precise mechanism by which NaV1.7 contributes to cancer progression and metastasis; many studies have suggested a connection between NaV1.7 and proteins involved in multiple signaling pathways such as PKA and EGF/EGFR-ERK1/2. Moreover, the functional activity of NaV1.7 appears to elevate the expression levels of MACC1 and NHE-1, which are controlled by p38 MAPK activity, HGF/c-MET signaling and c-Jun activity. This cascade potentially enhances the secretion of extracellular matrix proteases, such as MMPs which play critical roles in cell migration and invasion activities. Furthermore, the NaV1.7 activity may indirectly upregulate Rho GTPases Rac activity, which is critical for cytoskeleton reorganization, cell adhesion, and actin polymerization. The relationship between NaV1.7 and cancer progression has prompted researchers to investigate the therapeutic potential of targeting NaV1.7 using inhibitors. The positive outcome of such studies resulted in the discovery of several inhibitors with the ability to reduce cancer cell migration, invasion, and tumor growth underscoring the significance of NaV1.7 as a promising pharmacological target for attenuating cancer cell proliferation and metastasis. The research findings summarized in this review suggest that the regulation of NaV1.7 expression and function by small molecules and/or by genetic engineering is a viable approach to discover novel therapeutics for the prevention and treatment of metastasis of cancers with elevated NaV1.7 expression.
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Affiliation(s)
- Piyasuda Pukkanasut
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Renata Jaskula-Sztul
- Department of Surgery, The University of Alabama at Birmingham, Birmingham, AL, United States
- O’Neal Comprehensive Cancer Center, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Juan Carlos Gomora
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Sadanandan E. Velu
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, AL, United States
- O’Neal Comprehensive Cancer Center, The University of Alabama at Birmingham, Birmingham, AL, United States
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Rao R, Mohammed C, Alschuler L, Pomeranz Krummel DA, Sengupta S. Phytochemical Modulation of Ion Channels in Oncologic Symptomatology and Treatment. Cancers (Basel) 2024; 16:1786. [PMID: 38730738 PMCID: PMC11083444 DOI: 10.3390/cancers16091786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/24/2024] [Accepted: 05/04/2024] [Indexed: 05/13/2024] Open
Abstract
Modern chemotherapies offer a broad approach to cancer treatment but eliminate both cancer and non-cancer cells indiscriminately and, thus, are associated with a host of side effects. Advances in precision oncology have brought about new targeted therapeutics, albeit mostly limited to a subset of patients with an actionable mutation. They too come with side effects and, ultimately, 'self-resistance' to the treatment. There is recent interest in the modulation of ion channels, transmembrane proteins that regulate the flow of electrically charged molecules in and out of cells, as an approach to aid treatment of cancer. Phytochemicals have been shown to act on ion channels with high specificity regardless of the tumor's genetic profile. This paper explores the use of phytochemicals in cancer symptom management and treatment.
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Affiliation(s)
- Rohan Rao
- Department of Neurology & Rehabilitation Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Caroline Mohammed
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Lise Alschuler
- Andrew Weil Center for Integrative Medicine, University of Arizona College of Medicine, Tucson, AZ 85719, USA
| | - Daniel A. Pomeranz Krummel
- Department of Neurosurgery, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Soma Sengupta
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
- Department of Neurosurgery, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
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Wang Y, Javeed A, Jian C, Zeng Q, Han B. Precautions for seafood consumers: An updated review of toxicity, bioaccumulation, and rapid detection methods of marine biotoxins. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 274:116201. [PMID: 38489901 DOI: 10.1016/j.ecoenv.2024.116201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 03/03/2024] [Accepted: 03/08/2024] [Indexed: 03/17/2024]
Abstract
Seafood products are globally consumed, and there is an increasing demand for the quality and safety of these products among consumers. Some seafoods are easily contaminated by marine biotoxins in natural environments or cultured farming processes. When humans ingest different toxins accumulated in seafood, they may exhibit different poisoning symptoms. According to the investigations, marine toxins produced by harmful algal blooms and various other marine organisms mainly accumulate in the body organs such as liver and digestive tract of seafood animals. Several regions around the world have reported incidents of seafood poisoning by biotoxins, posing a threat to human health. Thus, most countries have legislated to specify the permissible levels of these biotoxins in seafood. Therefore, it is necessary for seafood producers and suppliers to conduct necessary testing of toxins in seafood before and after harvesting to prohibit excessive toxins containing seafood from entering the market, which therefore can reduce the occurrence of seafood poisoning incidents. In recent years, some technologies which can quickly, conveniently, and sensitively detect biological toxins in seafood, have been developed and validated, these technologies have the potential to help seafood producers, suppliers and regulatory authorities. This article reviews the seafood toxins sources and types, mechanism of action and bioaccumulation of marine toxins, as well as legislation and rapid detection technologies for biotoxins in seafood for official and fishermen supervision.
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Affiliation(s)
- Yifan Wang
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Ansar Javeed
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Cuiqin Jian
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Qiuyu Zeng
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Bingnan Han
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China.
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Pérez R, Figueredo C, Burgos V, Cabrera-Pardo JR, Schmidt B, Heydenreich M, Koch A, Deuis JR, Vetter I, Paz C. Natural Compounds Purified from the Leaves of Aristotelia chilensis: Makomakinol, a New Alkaloid and the Effect of Aristoteline and Hobartine on Na V Channels. Int J Mol Sci 2023; 24:15504. [PMID: 37958488 PMCID: PMC10650464 DOI: 10.3390/ijms242115504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 11/15/2023] Open
Abstract
Aristotelia chilensis or "maqui" is a tree native to Chile used in the folk medicine of the Mapuche people as an anti-inflammatory agent for the treatment of digestive ailments, fever, and skin lesions. Maqui fruits are black berries which are considered a "superfruit" with notable potential health benefits, promoted to be an antioxidant, cardioprotective, and anti-inflammatory. Maqui leaves contain non-iridoid monoterpene indole alkaloids which have previously been shown to act on nicotinic acetylcholine receptors, potassium channels, and calcium channels. Here, we isolated a new alkaloid from maqui leaves, now called makomakinol, together with the known alkaloids aristoteline, hobartine, and 3-formylindole. Moreover, the polyphenols quercetine, ethyl caffeate, and the terpenes, dihydro-β-ionone and terpin hydrate, were also obtained. In light of the reported analgesic and anti-nociceptive properties of A. chilensis, in particular a crude mixture of alkaloids containing aristoteline and hobartinol (PMID 21585384), we therefore evaluated the activity of aristoteline and hobartine on NaV1.8, a key NaV isoform involved in nociception, using automated whole-cell patch-clamp electrophysiology. Aristoteline and hobartine both inhibited Nav1.8 with an IC50 of 68 ± 3 µM and 54 ± 1 µM, respectively. Hobartine caused a hyperpolarizing shift of the voltage-dependence of the activation, whereas aristoteline did not change the voltage-dependence of the activation or inactivation. The inhibitory activity of these alkaloids on NaV channels may contribute to the reported analgesic properties of Aristotelia chilensis used by the Mapuche people.
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Affiliation(s)
- Rebeca Pérez
- Laboratory of Natural Products & Drug Discovery, Center CEBIM, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco 4780000, Chile; (R.P.); (C.F.)
| | - Claudia Figueredo
- Laboratory of Natural Products & Drug Discovery, Center CEBIM, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco 4780000, Chile; (R.P.); (C.F.)
| | - Viviana Burgos
- Departamento de Ciencias Biológicas y Químicas, Facultad de Recursos Naturales, Universidad Católica de Temuco, Rudecindo Ortega 02950, Temuco 4780000, Chile;
| | - Jaime R. Cabrera-Pardo
- Laboratorio de Química Aplicada y Sustentable (LabQAS), Departamento de Química, Facultad de Ciencias, Universidad del Bío-Bío, Concepción 4081112, Chile;
| | - Bernd Schmidt
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; (B.S.); (A.K.)
| | - Matthias Heydenreich
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; (B.S.); (A.K.)
| | - Andreas Koch
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; (B.S.); (A.K.)
| | - Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; (J.R.D.); (I.V.)
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; (J.R.D.); (I.V.)
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Cristian Paz
- Laboratory of Natural Products & Drug Discovery, Center CEBIM, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco 4780000, Chile; (R.P.); (C.F.)
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Voltage-Gated Sodium Channels: A Prominent Target of Marine Toxins. Mar Drugs 2021; 19:md19100562. [PMID: 34677461 PMCID: PMC8537899 DOI: 10.3390/md19100562] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/29/2021] [Accepted: 10/02/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are considered to be one of the most important ion channels given their remarkable physiological role. VGSCs constitute a family of large transmembrane proteins that allow transmission, generation, and propagation of action potentials. This occurs by conducting Na+ ions through the membrane, supporting cell excitability and communication signals in various systems. As a result, a wide range of coordination and physiological functions, from locomotion to cognition, can be accomplished. Drugs that target and alter the molecular mechanism of VGSCs’ function have highly contributed to the discovery and perception of the function and the structure of this channel. Among those drugs are various marine toxins produced by harmful microorganisms or venomous animals. These toxins have played a key role in understanding the mode of action of VGSCs and in mapping their various allosteric binding sites. Furthermore, marine toxins appear to be an emerging source of therapeutic tools that can relieve pain or treat VGSC-related human channelopathies. Several studies documented the effect of marine toxins on VGSCs as well as their pharmaceutical applications, but none of them underlined the principal marine toxins and their effect on VGSCs. Therefore, this review aims to highlight the neurotoxins produced by marine animals such as pufferfish, shellfish, sea anemone, and cone snail that are active on VGSCs and discuss their pharmaceutical values.
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Delivery of local anaesthetics by a self-assembled supramolecular system mimicking their interactions with a sodium channel. Nat Biomed Eng 2021; 5:1099-1109. [PMID: 34518656 DOI: 10.1038/s41551-021-00793-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 08/09/2021] [Indexed: 01/04/2023]
Abstract
Site-1 sodium channel blockers (S1SCBs) act as potent local anaesthetics, but they can cause severe systemic toxicity. Delivery systems can be used to reduce the toxicity, but the hydrophilicity of S1SCBs makes their encapsulation challenging. Here, we report a self-assembling delivery system for S1SCBs whose design is inspired by the specific interactions of S1SCBs with two peptide sequences on the sodium channel. Specifically, the peptides were modified with hydrophobic domains so that they could assemble into nanofibres that facilitated specific binding with the S1SCBs tetrodotoxin, saxitoxin and dicarbamoyl saxitoxin. Injection of S1SCB-carrying nanofibres at the sciatic nerves of rats led to prolonged nerve blockade and to reduced systemic toxicity, with benign local-tissue reaction. The strategy of mimicking a molecular binding site via supramolecular interactions may be applicable more broadly to the design of drug delivery systems for receptor-mediated drugs.
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Activation of voltage-gated sodium channels by BmK NT1 augments NMDA receptor function through Src family kinase signaling pathway in primary cerebellar granule cell cultures. Neuropharmacology 2020; 180:108291. [PMID: 32931812 DOI: 10.1016/j.neuropharm.2020.108291] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 08/23/2020] [Accepted: 08/26/2020] [Indexed: 12/29/2022]
Abstract
Voltage-gated sodium channels (VGSCs) are responsible for the generation and propagation of action potentials in excitable cells and are the molecular targets of an array of neurotoxins. BmK NT1, an α-scorpion toxin obtained from the scorpion Buthus martensii Karsch (BmK), produces neurotoxicity that is associated with extracellular Ca2+ influx through Na+-Ca2+ exchangers, N-methyl-d-aspartic acid (NMDA) receptors, and L-type Ca2+ channels in cultured cerebellar granule cells (CGCs). In the present study, we demonstrated that BmK NT1 triggered concentration-dependent release of excitatory neurotransmitters, glutamate and aspartate; both effects were eliminated by VGSC blocker, tetrodotoxin. More importantly, we demonstrated that a threshold concentration of BmK NT1 that produced marginal Ca2+ influx and neuronal death augmented glutamate-induced Ca2+ elevation and neuronal death in CGCs. BmK NT1-augmented glutamate-induced Ca2+ influx and neuronal death were suppressed by tetrodotoxin and MK-801 suggesting that the augmentation was through activation of VGSCs and NMDA receptors. Consistently, BmK NT1 also enhanced NMDA-induced Ca2+ influx. Further mechanistic investigations demonstrated that BmK NT1 increased the expression level of NMDA receptors on the plasma membrane and increased the phosphorylation level of NR2B at Tyr1472. Src family kinase inhibitor, 1-tert-butyl-3-(4-chlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl]amine (PP2), but not the inactive analogue, 4-amino-1-phenylpyrazolo[3,4-d]pyrimidine (PP3), eliminated BmK NT1-triggered NR2B phosphorylation, NMDA receptor trafficking, as well as BmK NT1-augmented NMDA Ca2+ response and neuronal death. Considered together, these data demonstrated that both presynaptic (excitatory amino acid release) and postsynaptic mechanisms (augmentation of NMDA receptor function) are critical for VGSC activation-induced neurotoxicity in primary CGC cultures.
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Chen W, Zhang Y, Fang H, Chen H, He J, Yi R, Hong Z. Development and validation of a specific and sensitive liquid chromatography tandem mass spectrometry method for determination of tetrodotoxin in human urine and its pharmacokinetic study. Biomed Chromatogr 2020; 34:e4900. [PMID: 32428255 DOI: 10.1002/bmc.4900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 11/12/2022]
Abstract
Tetrodotoxin (TTX) exhibits the therapeutic potential in blocking pain and in low doses can safely relieve severe pain. The urinary excretion profiles of TTX in humans have not been reported due to the extremely low lethal dose. In this study, a rapid and specific method based on protein precipitation coupled to liquid chromatography tandem mass spectrometry was developed to determine the level of TTX in human urine samples. 11-Deoxytetrodotoxin was used as an internal standard (IS). Multiple reaction monitoring mode was used for quantification using target fragment ions m/z 320.0 → 162.1 for TTX and m/z 304.0 → 176.0 for 11-deoxyTTX. The separation of analytes was achieved on a hydrophilic interaction liquid chromatography column (250 × 4.6 mm, 5.0 μm). The mobile phase consisted of 5 mM ammonium formate in water (pH = 4.50) and 5 mM ammonium formate in acetonitrile (pH = 4.50). The flow rate was set at 0.80 mL/min in a gradient condition. Calibration plots were linear throughout the range 0.986-98.6 ng/mL of TTX in human urine. The intra-assay accuracies and precisions were within the acceptable range. The method was successfully applied to a urinary excretion study after intravenous administration of TTX to healthy volunteers. The developed method will be helpful for future pharmacological studies of TTX.
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Affiliation(s)
- Weizhu Chen
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
| | - Yiping Zhang
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
| | - Hua Fang
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
| | - Hui Chen
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
| | - Jianlin He
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
| | - Ruizao Yi
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
| | - Zhuan Hong
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, China.,Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Ministry of Natural Resource, Xiamen, China.,Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological, Xiamen, China
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10
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Using Toxins in Brain Slice Recordings. Methods Mol Biol 2019. [PMID: 31576533 DOI: 10.1007/978-1-4939-9845-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Use of biological toxins from different kinds is widely accepted in electrophysiological experiments. In particular, electrophysiological recordings from brain tissue slices are usually conducted with toxins to manipulate on different receptors or ion channels. Here we describe usage of toxins in electrophysiological experiments in acute brain slices.
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11
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Xu L, Ding X, Wang T, Mou S, Sun H, Hou T. Voltage-gated sodium channels: structures, functions, and molecular modeling. Drug Discov Today 2019; 24:1389-1397. [PMID: 31129313 DOI: 10.1016/j.drudis.2019.05.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/02/2019] [Accepted: 05/17/2019] [Indexed: 10/26/2022]
Abstract
Voltage-gated sodium channels (VGSCs), formed by 24 transmembrane segments arranged into four domains, have a key role in the initiation and propagation of electrical signaling in excitable cells. VGSCs are involved in a variety of diseases, including epilepsy, cardiac arrhythmias, and neuropathic pain, and therefore have been regarded as appealing therapeutic targets for the development of anticonvulsant, antiarrhythmic, and local anesthetic drugs. In this review, we discuss recent advances in understanding the structures and biological functions of VGSCs. In addition, we systematically summarize eight pharmacologically distinct ligand-binding sites in VGSCs and representative isoform-selective VGSC modulators in clinical trials. Finally, we review studies on molecular modeling and computer-aided drug design (CADD) for VGSCs to help understanding of biological processes involving VGSCs.
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Affiliation(s)
- Lei Xu
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Xiaoqin Ding
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China
| | - Tianhu Wang
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Shanzhi Mou
- School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China
| | - Huiyong Sun
- Department of Medicinal Chemistry, School of Pharmacy, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China.
| | - Tingjun Hou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
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Zhao F, Tang Q, Xu J, Wang S, Li S, Zou X, Cao Z. Dehydrocrenatidine Inhibits Voltage-Gated Sodium Channels and Ameliorates Mechanic Allodia in a Rat Model of Neuropathic Pain. Toxins (Basel) 2019; 11:E229. [PMID: 31003411 PMCID: PMC6521113 DOI: 10.3390/toxins11040229] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 12/27/2022] Open
Abstract
Picrasma quassioides (D. Don) Benn, a medical plant, is used in clinic to treat inflammation, pain, sore throat, and eczema. The alkaloids are the main active components in P. quassioides. In this study, we examined the analgesic effect of dehydrocrenatidine (DHCT), a β-carboline alkaloid abundantly found in P. quassioides in a neuropathic pain rat model of a sciatic nerve chronic constriction injury. DHCT dose-dependently attenuated the mechanic allodynia. In acutely isolated dorsal root ganglion, DHCT completely suppressed the action potential firing. Further electrophysiological characterization demonstrated that DHCT suppressed both tetrodotoxin-resistant (TTX-R) and sensitive (TTX-S) voltage-gated sodium channel (VGSC) currents with IC50 values of 12.36 μM and 4.87 µM, respectively. DHCT shifted half-maximal voltage (V1/2) of inactivation to hyperpolarizing direction by ~16.7 mV in TTX-S VGSCs. In TTX-R VGSCs, DHCT shifted V1/2 of inactivation voltage to hyperpolarizing direction and V1/2 of activation voltage to more depolarizing potential by ~23.9 mV and ~12.2 mV, respectively. DHCT preferred to interact with an inactivated state of VGSCs and prolonged the repriming time in both TTX-S and TTX-R VGSCs, transiting the channels into a slow inactivated state from a fast inactivated state. Considered together, these data demonstrated that the analgesic effect of DHCT was likely though the inhibition of neuronal excitability.
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Affiliation(s)
- Fang Zhao
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Qinglian Tang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Jian Xu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Shuangyan Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Shaoheng Li
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Xiaohan Zou
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Zhengyu Cao
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
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13
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Anand A, Chi CH, Banerjee S, Chou MY, Tseng FG, Pan CY, Chen YT. The Extracellular Zn 2+ Concentration Surrounding Excited Neurons Is High Enough to Bind Amyloid-β Revealed by a Nanowire Transistor. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1704439. [PMID: 29770576 DOI: 10.1002/smll.201704439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/07/2018] [Indexed: 06/08/2023]
Abstract
The Zn2+ stored in the secretory vesicles of glutamatergic neurons is coreleased with glutamate upon stimulation, resulting in the elevation of extracellular Zn2+ concentration (CZn2+ex). This elevation of CZn2+ex regulates the neurotransmission and facilitates the fibrilization of amyloid-β (Aβ). However, the exact CZn2+ex surrounding neurons under (patho)physiological conditions is not clear and the connection between CZn2+ex and the Aβ fibrilization remains obscure. Here, a silicon nanowire field-effect transistor (SiNW-FET) with the Zn2+ -sensitive fluorophore, FluoZin-3 (FZ-3), to quantify the CZn2+ex in real time is modified. This FZ-3/SiNW-FET device has a dissociation constant of ≈12 × 10-9 m against Zn2+ . By placing a coverslip seeded with cultured embryonic cortical neurons atop an FZ-3/SiNW-FET, the CZn2+ex elevated to ≈110 × 10-9 m upon stimulation with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). Blockers against the AMPA receptor or exocytosis greatly suppress this elevation, indicating that the Zn2+ stored in the synaptic vesicles is the major source responsible for this elevation of CZn2+ex. In addition, a SiNW-FET modified with Aβ could bind Zn2+ with a dissociation constant of ≈633 × 10-9 m and respond to the Zn2+ released from AMPA-stimulated neurons. Therefore, the CZn2+ex can reach a level high enough to bind Aβ and the Zn2+ homeostasis can be a therapeutic strategy to prevent neurodegeneration.
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Affiliation(s)
- Ankur Anand
- Department of Engineering and System Science, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Nanoscience and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei, 115, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106, Taiwan
| | - Chih-Hung Chi
- Department of Life Science, National Taiwan University, Taipei, 106, Taiwan
| | - Subhasree Banerjee
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106, Taiwan
- Department of Life Science, National Taiwan University, Taipei, 106, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
| | - Ming-Yi Chou
- Department of Life Science, National Taiwan University, Taipei, 106, Taiwan
| | - Fan-Gang Tseng
- Department of Engineering and System Science, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, 115, Taiwan
| | - Chien-Yuan Pan
- Department of Life Science, National Taiwan University, Taipei, 106, Taiwan
| | - Yit-Tsong Chen
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 106, Taiwan
- Department of Chemistry, National Taiwan University, Taipei, 106, Taiwan
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14
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Cardoso FC, Lewis RJ. Sodium channels and pain: from toxins to therapies. Br J Pharmacol 2018; 175:2138-2157. [PMID: 28749537 PMCID: PMC5980290 DOI: 10.1111/bph.13962] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/11/2017] [Accepted: 07/17/2017] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium channels (NaV channels) are essential for the initiation and propagation of action potentials that critically influence our ability to respond to a diverse range of stimuli. Physiological and pharmacological studies have linked abnormal function of NaV channels to many human disorders, including chronic neuropathic pain. These findings, along with the description of the functional properties and expression pattern of NaV channel subtypes, are helping to uncover subtype specific roles in acute and chronic pain and revealing potential opportunities to target these with selective inhibitors. High-throughput screens and automated electrophysiology platforms have identified natural toxins as a promising group of molecules for the development of target-specific analgesics. In this review, the role of toxins in defining the contribution of NaV channels in acute and chronic pain states and their potential to be used as analgesic therapies are discussed. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
- Fernanda C Cardoso
- Department of Chemistry and Structural Biology, Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLDAustralia
| | - Richard J Lewis
- Department of Chemistry and Structural Biology, Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLDAustralia
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15
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Xu L, Li D, Ding J, Pan L, Ding X. Insight into tetrodotoxin blockade and resistance mechanisms of Na v 1.2 sodium channel by theoretical approaches. Chem Biol Drug Des 2018; 92:1445-1457. [PMID: 29673065 DOI: 10.1111/cbdd.13310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/08/2018] [Accepted: 03/17/2018] [Indexed: 11/30/2022]
Abstract
Nav 1.2, a member of voltage-gated sodium channels (Nav s) that are responsible for the generation and propagation of action potentials along the cell membrane, and play a vital role in the process of information transmission within the nervous system and muscle contraction, is preferentially expressed in the central nervous system. As a potent and selective blocker of Nav s, tetrodotoxin (TTX) has been extensively studied in biological and chemical sciences, whereas the detailed mechanism by which it blocks nine Nav 1 channel subtypes remain elusive. Despite the high structural similarity, the TTX metabolite 4,9-anhydro-TTX is 161 times less effective toward the mammalian Nav 1.2, which puzzled us to ask a question why such a subtle structural variation results in the largely binding affinity difference. In the current work, an integrated computational strategy, including homology modeling, induced fit docking, explicit-solvent MD simulations, and free energy calculations, was employed to investigate the binding mechanism and conformational determinants of TTX analogs. Based on the computational results, the H-bond interactions between C4-OH and C9-OH of TTX and the outer ring carboxylates of the selectivity-filter residues, and the cation-π interaction between the primary amine of guanidinium of TTX and Phe385 determine the difference of their binding affinities. Moreover, the computationally simulations were carried out for the D384N and E945K mutants of hNav 1.2-TTX, and the rank of the predicted binding free energies is in accordance with the experimental data. These observations provide a valuable model to design potent and selective neurotoxins of Nav 1.2 and shed light on the blocking mechanism of TTX to sodium channels.
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Affiliation(s)
- Lei Xu
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou, China
| | - Dayu Li
- Beijing Institute of Pharmaceutical Chemistry, Beijing, China
| | - Junjie Ding
- Beijing Institute of Pharmaceutical Chemistry, Beijing, China
| | - Li Pan
- Beijing Institute of Pharmaceutical Chemistry, Beijing, China
| | - Xiaoqin Ding
- Beijing Institute of Pharmaceutical Chemistry, Beijing, China
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16
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Yin X, Kiriake A, Ohta A, Kitani Y, Ishizaki S, Nagashima Y. A novel function of vitellogenin subdomain, vWF type D, as a toxin-binding protein in the pufferfish Takifugu pardalis ovary. Toxicon 2017; 136:56-66. [PMID: 28651990 DOI: 10.1016/j.toxicon.2017.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/25/2017] [Accepted: 06/10/2017] [Indexed: 10/19/2022]
Abstract
Marine pufferfish of the Tetraodontidae family contain high levels of tetrodotoxin (TTX) in the liver and ovary. TTX is suggested to transfer from the liver to the ovary in female pufferfish during maturation. TTX in pufferfish eggs may act as a repellent against predators and as a sexual pheromone to attract male pufferfish. The toxification mechanism of the pufferfish ovary is poorly understood. Here we evaluated the chemical form of TTX and its related substances in the ovary of the panther pufferfish Takifugu pardalis by LC-ESI/MS. TTX and its analogs 4-epi-TTX, 4, 9-anhydroTTX, deoxyTTX, dideoxyTTX, and trideoxyTTX were detected in a low molecular weight fraction by Sephacryl S-400 column chromatography. The finding of an unknown TTX-related substance in a high molecular weight fraction from the Sephacryl S-400 column suggested the occurrence of toxin-binding protein in the ovary. The toxin-binding protein in the ovary was purified by ion-exchange HPLC, gel filtration HPLC, and SDS-PAGE. Amino acid sequencing and cDNA cloning revealed that the toxin-binding protein, TPOBP-10 (Takifugu pardalis ovary toxin-binding protein with a molecular mass of 10 kDa) was homologous with the predicted vitellogenin-1-like protein [Takifugu rubripes] subdomain, a von Willebrand factor type D domain. TPOBP-10 mRNA was highly expressed in the ovary and liver and less in other organs of female individuals based on RT-PCR. These findings reveal a novel function of the vitellogenin subdomain as binding with TTX-related substances, and its involvement in the toxification of the pufferfish ovary.
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Affiliation(s)
- Xianzhe Yin
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan
| | - Aya Kiriake
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan
| | - Akira Ohta
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan
| | - Yoichiro Kitani
- Faculty of Biosciences and Aquaculture, NORD University, Bodø 8049, Norway
| | - Shoichiro Ishizaki
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan
| | - Yuji Nagashima
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan.
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17
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Tetrodotoxin-Producing Bacteria: Detection, Distribution and Migration of the Toxin in Aquatic Systems. Toxins (Basel) 2017; 9:toxins9050166. [PMID: 28513564 PMCID: PMC5450714 DOI: 10.3390/toxins9050166] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/12/2017] [Accepted: 05/12/2017] [Indexed: 01/18/2023] Open
Abstract
This review is devoted to the marine bacterial producers of tetrodotoxin (TTX), a potent non-protein neuroparalytic toxin. In addition to the issues of the ecology and distribution of TTX-producing bacteria, this review examines issues relating to toxin migration from bacteria to TTX-bearing animals. It is shown that the mechanism of TTX extraction from toxin-producing bacteria to the environment occur through cell death, passive/active toxin excretion, or spore germination of spore-forming bacteria. Data on TTX microdistribution in toxic organs of TTX-bearing animals indicate toxin migration from the digestive system to target organs through the transport system of the organism. The role of symbiotic microflora in animal toxicity is also discussed: despite low toxin production by bacterial strains in laboratory conditions, even minimal amounts of TTX produced by intestinal microflora of an animal can contribute to its toxicity. Special attention is paid to methods of TTX detection applicable to bacteria. Due to the complexity of toxin detection in TTX-producing bacteria, it is necessary to use several methods based on different methodological approaches. Issues crucial for further progress in detecting natural sources of TTX investigation are also considered.
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18
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Hoogenboom LR, Nebbia CS, Oswald IP, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Arnich N, Benford D, Botana L, Viviani B, Arcella D, Binaglia M, Horvath Z, Steinkellner H, van Manen M, Petersen A. Risks for public health related to the presence of tetrodotoxin (TTX) and TTX analogues in marine bivalves and gastropods. EFSA J 2017; 15:e04752. [PMID: 32625458 PMCID: PMC7010203 DOI: 10.2903/j.efsa.2017.4752] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Tetrodotoxin (TTX) and its analogues are produced by marine bacteria and have been detected in marine bivalves and gastropods from European waters. The European Commission asked EFSA for a scientific opinion on the risks to public health related to the presence of TTX and TTX analogues in marine bivalves and gastropods. The Panel on Contaminants in the Food Chain reviewed the available literature but did not find support for the minimum lethal dose for humans of 2 mg, mentioned in various reviews. Some human case reports describe serious effects at a dose of 0.2 mg, corresponding to 4 μg/kg body weight (bw). However, the uncertainties on the actual exposure in the studies preclude their use for derivation of an acute reference dose (ARfD). Instead, a group ARfD of 0.25 μg/kg bw, applying to TTX and its analogues, was derived based on a TTX dose of 25 μg/kg bw at which no apathy was observed in an acute oral study with mice, applying a standard uncertainty factor of 100. Estimated relative potencies for analogues are lower than that of TTX but are associated with a high degree of uncertainty. Based on the occurrence data submitted to EFSA and reported consumption days only, average and P95 exposures of 0.00-0.09 and 0.00-0.03 μg/kg bw, respectively, were calculated. Using a large portion size of 400 g bivalves and P95 occurrence levels of TTX, with exception of oysters, the exposure was below the group ARfD in all consumer groups. A concentration below 44 μg TTX equivalents/kg shellfish meat, based on a large portion size of 400 g, was considered not to result in adverse effects in humans. Liquid chromatography with tandem mass spectroscopy (LC-MS/MS) methods are the most suitable for identification and quantification of TTX and its analogues, with LOQs between 1 and 25 μg/kg.
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19
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20
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Bane V, Brosnan B, Barnes P, Lehane M, Furey A. High-resolution mass spectrometry analysis of tetrodotoxin (TTX) and its analogues in puffer fish and shellfish. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2016; 33:1468-89. [DOI: 10.1080/19440049.2016.1218070] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Vaishali Bane
- Mass Spectrometry Research Centre (MSRC), Department of Physical Sciences, Cork Institute of Technology, Cork, Ireland
| | - Brid Brosnan
- Mass Spectrometry Research Centre (MSRC), Department of Physical Sciences, Cork Institute of Technology, Cork, Ireland
| | - Paul Barnes
- Agri-food and Biosciences Institute, Belfast, UK
| | - Mary Lehane
- Mass Spectrometry Research Centre (MSRC), Department of Physical Sciences, Cork Institute of Technology, Cork, Ireland
| | - Ambrose Furey
- Mass Spectrometry Research Centre (MSRC), Department of Physical Sciences, Cork Institute of Technology, Cork, Ireland
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21
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Patel D, Mahdavi S, Kuyucak S. Computational Study of Binding of μ-Conotoxin GIIIA to Bacterial Sodium Channels NaVAb and NaVRh. Biochemistry 2016; 55:1929-38. [PMID: 26959170 DOI: 10.1021/acs.biochem.5b01324] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Structures of several voltage-gated sodium (NaV) channels from bacteria have been determined recently, but the same feat might not be achieved for the mammalian counterparts in the near future. Thus, at present, computational studies of the mammalian NaV channels have to be performed using homology models based on the bacterial crystal structures. A successful homology model for the mammalian NaV1.4 channel was recently constructed using the extensive mutation data for binding of μ-conotoxin GIIIA to NaV1.4, which was further validated through studies of binding of other μ-conotoxins and ion permeation. Understanding the similarities and differences between the bacterial and mammalian NaV channels is an important issue, and the NaV1.4-GIIIA system provides a good opportunity for such a comparison. To this end, we study the binding of GIIIA to the bacterial channels NaVAb and NaVRh. The complex structures are obtained using docking and molecular dynamics simulations, and the dissociation of GIIIA is studied through umbrella sampling simulations. The results are compared to those obtained from the NaV1.4-GIIIA system, and the differences in the binding modes arising from the changes in the selectivity filters are highlighted.
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Affiliation(s)
- Dharmeshkumar Patel
- School of Physics, University of Sydney , Sydney, New South Wales 2006, Australia
| | - Somayeh Mahdavi
- School of Physics, University of Sydney , Sydney, New South Wales 2006, Australia
| | - Serdar Kuyucak
- School of Physics, University of Sydney , Sydney, New South Wales 2006, Australia
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22
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Zhorov B, Tikhonov D. Computational Structural Pharmacology and Toxicology of Voltage-Gated Sodium Channels. NA CHANNELS FROM PHYLA TO FUNCTION 2016; 78:117-44. [DOI: 10.1016/bs.ctm.2015.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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23
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Guodong F, Mingming G, Qi L, Hongyu M, Guanghua L, Qiang M, Qiang F, Yanfu H, Zhiguang S. One-pot synthesis and application of novel amino-functionalized silica nanoparticles using guanidine as amino group. NEW J CHEM 2016. [DOI: 10.1039/c6nj02094a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The preparation of modified silica nanoparticles with guanidine was developed and used to catalyze the Henry reaction and fix quantum dots.
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Affiliation(s)
- Feng Guodong
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Guan Mingming
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Lai Qi
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Mi Hongyu
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Li Guanghua
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry
- College of Chemistry
- Jilin University
- Changchun 130021
- China
| | - Ma Qiang
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Fei Qiang
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Huan Yanfu
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
| | - Song Zhiguang
- College of Chemistry
- Jilin University
- Changchun 130021
- P. R. China
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24
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Frolov RV, Weckström M. Harnessing the Flow of Excitation: TRP, Voltage-Gated Na(+), and Voltage-Gated Ca(2+) Channels in Contemporary Medicine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:25-95. [PMID: 26920687 DOI: 10.1016/bs.apcsb.2015.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular signaling in both excitable and nonexcitable cells involves several classes of ion channels. Some of them are of minor importance, with very specialized roles in physiology, but here we concentrate on three major channel classes: TRP (transient receptor potential channels), voltage-gated sodium channels (Nav), and voltage-gated calcium channels (Cav). Here, we first propose a conceptual framework binding together all three classes of ion channels, a "flow-of-excitation model" that takes into account the inputs mediated by TRP and other similar channels, the outputs invariably provided by Cav channels, and the regenerative transmission of signals in the neural networks, for which Nav channels are responsible. We use this framework to examine the function, structure, and pharmacology of these channel classes both at cellular and also at whole-body physiological level. Building on that basis we go through the pathologies arising from the direct or indirect malfunction of the channels, utilizing ion channel defects, the channelopathies. The pharmacological interventions affecting these channels are numerous. Part of those are well-established treatments, like treatment of hypertension or some forms of epilepsy, but many other are deeply problematic due to poor drug specificity, ion channel diversity, and widespread expression of the channels in tissues other than those actually targeted.
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Affiliation(s)
- Roman V Frolov
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland.
| | - Matti Weckström
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland
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25
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Computational approaches for designing potent and selective analogs of peptide toxins as novel therapeutics. Future Med Chem 2015; 6:1645-58. [PMID: 25406005 DOI: 10.4155/fmc.14.98] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Peptide toxins provide valuable therapeutic leads for many diseases. As they bind to their targets with high affinity, potency is usually ensured. However, toxins also bind to off-target receptors, causing potential side effects. Thus, a major challenge in generating drugs from peptide toxins is ensuring their specificity for their intended targets. Computational methods can play an important role in solving such design problems through construction of accurate models of receptor-toxin complexes and calculation of binding free energies. Here we review the computational methods used for this purpose and their application to toxins targeting ion channels. We describe ShK and HsTX1 toxins, high-affinity blockers of the voltage-gated potassium channel Kv1.3, which could be developed as therapeutic agents for autoimmune diseases.
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26
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Gintant G. Cardiac Sodium Current (Na v1.5). METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2015. [DOI: 10.1002/9783527673643.ch12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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27
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de Lera Ruiz M, Kraus RL. Voltage-Gated Sodium Channels: Structure, Function, Pharmacology, and Clinical Indications. J Med Chem 2015; 58:7093-118. [PMID: 25927480 DOI: 10.1021/jm501981g] [Citation(s) in RCA: 322] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The tremendous therapeutic potential of voltage-gated sodium channels (Na(v)s) has been the subject of many studies in the past and is of intense interest today. Na(v)1.7 channels in particular have received much attention recently because of strong genetic validation of their involvement in nociception. Here we summarize the current status of research in the Na(v) field and present the most relevant recent developments with respect to the molecular structure, general physiology, and pharmacology of distinct Na(v) channel subtypes. We discuss Na(v) channel ligands such as small molecules, toxins isolated from animal venoms, and the recently identified Na(v)1.7-selective antibody. Furthermore, we review eight characterized ligand binding sites on the Na(v) channel α subunit. Finally, we examine possible therapeutic applications of Na(v) ligands and provide an update on current clinical studies.
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Affiliation(s)
- Manuel de Lera Ruiz
- Merck Research Laboratories , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Richard L Kraus
- Merck Research Laboratories , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
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28
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Li Y, Gong H. Theoretical and simulation studies on voltage-gated sodium channels. Protein Cell 2015; 6:413-22. [PMID: 25894089 PMCID: PMC4444806 DOI: 10.1007/s13238-015-0152-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/05/2015] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are indispensable membrane elements for the generation and propagation of electric signals in excitable cells. The successes in the crystallographic studies on prokaryotic Nav channels in recent years greatly promote the mechanistic investigation of these proteins and their eukaryotic counterparts. In this paper, we mainly review the progress in computational studies, especially the simulation studies, on these proteins in the past years.
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Affiliation(s)
- Yang Li
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Haipeng Gong
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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29
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Zimmer T, Haufe V, Blechschmidt S. Voltage-gated sodium channels in the mammalian heart. Glob Cardiol Sci Pract 2014; 2014:449-63. [PMID: 25780798 PMCID: PMC4355518 DOI: 10.5339/gcsp.2014.58] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/11/2014] [Indexed: 12/19/2022] Open
Abstract
Mammalian species express nine functional voltage-gated Na(+) channels. Three of them, the cardiac-specific isoform Nav1.5 and the neuronal isoforms Nav1.8 and Nav1.9, are relatively resistant to the neurotoxin tetrodotoxin (TTX; IC50 ≥ 1 μM). The other six isoforms are highly sensitive to TTX with IC50 values in the nanomolar range. These isoforms are expressed in the central nervous system (Nav1.1, Nav1.2, Nav1.3, Nav1.6), in the skeletal muscle (Nav1.4), and in the peripheral nervous system (Nav1.6, Nav1.7). The isoform Nav1.5, encoded by the SCN5A gene, is responsible for the upstroke of the action potential in the heart. Mutations in SCN5A are associated with a variety of life-threatening arrhythmias, like long QT syndrome type 3 (LQT3), Brugada syndrome (BrS) or cardiac conduction disease (CCD). Previous immunohistochemical and electrophysiological assays demonstrated the cardiac expression of neuronal and skeletal muscle Na(+) channels in the heart of various mammals, which led to far-reaching speculations on their function. However, when comparing the Na(+) channel mRNA patterns in the heart of various mammalian species, only minute quantities of transcripts for TTX-sensitive Na(+) channels were detectable in whole pig and human hearts, suggesting that these channels are not involved in cardiac excitation phenomena in higher mammals. This conclusion is strongly supported by the fact that mutations in TTX-sensitive Na(+) channels were associated with epilepsy or skeletal muscle diseases, rather than with a pathological cardiac phenotype. Moreover, previous data from TTX-intoxicated animals and from cases of human tetrodotoxication showed that low TTX dosages caused at most little alterations of both the cardiac output and the electrocardiogram. Recently, genome-wide association studies identified SCN10A, the gene encoding Nav1.8, as a determinant of cardiac conduction parameters, and mutations in SCN10A have been associated with BrS. These novel findings opened a fascinating new research area in the cardiac ion channel field, and the on-going debate on how SCN10A/Nav1.8 affects cardiac conduction is very exciting.
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Affiliation(s)
- Thomas Zimmer
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Kollegiengasse 9, 07743 Jena, Germany
| | | | - Steve Blechschmidt
- Institute of Physiology II, University Hospital Jena, Friedrich Schiller University, Kollegiengasse 9, 07743 Jena, Germany
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Systematic study of binding of μ-conotoxins to the sodium channel NaV1.4. Toxins (Basel) 2014; 6:3454-70. [PMID: 25529306 PMCID: PMC4280544 DOI: 10.3390/toxins6123454] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/01/2014] [Accepted: 12/10/2014] [Indexed: 01/25/2023] Open
Abstract
Voltage-gated sodium channels (NaV) are fundamental components of the nervous system. Their dysfunction is implicated in a number of neurological disorders, such as chronic pain, making them potential targets for the treatment of such disorders. The prominence of the NaV channels in the nervous system has been exploited by venomous animals for preying purposes, which have developed toxins that can block the NaV channels, thereby disabling their function. Because of their potency, such toxins could provide drug leads for the treatment of neurological disorders associated with NaV channels. However, most toxins lack selectivity for a given target NaV channel, and improving their selectivity profile among the NaV1 isoforms is essential for their development as drug leads. Computational methods will be very useful in the solution of such design problems, provided accurate models of the protein-ligand complex can be constructed. Using docking and molecular dynamics simulations, we have recently constructed a model for the NaV1.4-μ-conotoxin-GIIIA complex and validated it with the ample mutational data available for this complex. Here, we use the validated NaV1.4 model in a systematic study of binding other μ-conotoxins (PIIIA, KIIIA and BuIIIB) to NaV1.4. The binding mode obtained for each complex is shown to be consistent with the available mutation data and binding constants. We compare the binding modes of PIIIA, KIIIA and BuIIIB to that of GIIIA and point out the similarities and differences among them. The detailed information about NaV1.4-μ-conotoxin interactions provided here will be useful in the design of new NaV channel blocking peptides.
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Payandeh J, Minor DL. Bacterial voltage-gated sodium channels (BacNa(V)s) from the soil, sea, and salt lakes enlighten molecular mechanisms of electrical signaling and pharmacology in the brain and heart. J Mol Biol 2014; 427:3-30. [PMID: 25158094 DOI: 10.1016/j.jmb.2014.08.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/11/2014] [Accepted: 08/18/2014] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels (Na(V)s) provide the initial electrical signal that drives action potential generation in many excitable cells of the brain, heart, and nervous system. For more than 60years, functional studies of Na(V)s have occupied a central place in physiological and biophysical investigation of the molecular basis of excitability. Recently, structural studies of members of a large family of bacterial voltage-gated sodium channels (BacNa(V)s) prevalent in soil, marine, and salt lake environments that bear many of the core features of eukaryotic Na(V)s have reframed ideas for voltage-gated channel function, ion selectivity, and pharmacology. Here, we analyze the recent advances, unanswered questions, and potential of BacNa(V)s as templates for drug development efforts.
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Affiliation(s)
- Jian Payandeh
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA 94080, USA.
| | - Daniel L Minor
- Cardiovascular Research Institute, Departments of Biochemistry and Biophysics and Cellular and Molecular Pharmacology, California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA 93858-2330, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Attili S, Hughes SM. Anaesthetic tricaine acts preferentially on neural voltage-gated sodium channels and fails to block directly evoked muscle contraction. PLoS One 2014; 9:e103751. [PMID: 25090007 PMCID: PMC4121177 DOI: 10.1371/journal.pone.0103751] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 06/30/2014] [Indexed: 12/15/2022] Open
Abstract
Movements in animals arise through concerted action of neurons and skeletal muscle. General anaesthetics prevent movement and cause loss of consciousness by blocking neural function. Anaesthetics of the amino amide-class are thought to act by blockade of voltage-gated sodium channels. In fish, the commonly used anaesthetic tricaine methanesulphonate, also known as 3-aminobenzoic acid ethyl ester, metacaine or MS-222, causes loss of consciousness. However, its role in blocking action potentials in distinct excitable cells is unclear, raising the possibility that tricaine could act as a neuromuscular blocking agent directly causing paralysis. Here we use evoked electrical stimulation to show that tricaine efficiently blocks neural action potentials, but does not prevent directly evoked muscle contraction. Nifedipine-sensitive L-type Cav channels affecting movement are also primarily neural, suggesting that muscle Nav channels are relatively insensitive to tricaine. These findings show that tricaine used at standard concentrations in zebrafish larvae does not paralyse muscle, thereby diminishing concern that a direct action on muscle could mask a lack of general anaesthesia.
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Affiliation(s)
- Seetharamaiah Attili
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London, United Kingdom
| | - Simon M. Hughes
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London, United Kingdom
- * E-mail:
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