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Gambierol, a toxin produced by the dinoflagellate Gambierdiscus toxicus, is a potent blocker of voltage-gated potassium channels
Cuypers, E.; Abdel-Mottaleb, Y.; Kopljar, I.; Rainier, J.; Raes, A.L.; Snyders, D.J.; Tytgat, J. (2008). Gambierol, a toxin produced by the dinoflagellate Gambierdiscus toxicus, is a potent blocker of voltage-gated potassium channels. Toxicon 51(6): 974-983. dx.doi.org/10.1016/j.toxicon.2008.01.004
In: Toxicon. Elsevier: Oxford. ISSN 0041-0101, more
Peer reviewed article  

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Keyword
    Marine
Author keywords
    gambierol; ciguatera fish poisoning; voltage-gated potassium channels;voltage-gated sodium channels

Authors  Top 
  • Cuypers, E., more
  • Abdel-Mottaleb, Y., more
  • Kopljar, I., more
  • Rainier, J.

Abstract
    In this study, we pharmacologically characterized gambierol, a marine polycyclic ether toxin which is produced by the dinoflagellate Gambierdiscus toxicus. Besides several other polycyclic ether toxins like ciguatoxins, this scarcely studied toxin is one of the compounds that may be responsible for ciguatera fish poisoning (CFP). Unfortunately, the biological target(s) that underlies CFP is still partly unknown. Today, ciguatoxins are described to specifically activate voltage-gated sodium channels by interacting with their receptor site 5. But some dispute about the role of gambierol in the CFP story shows up: some describe voltage-gated sodium channels as the target, while others pinpoint voltage-gated potassium channels as targets. Since gambierol was never tested on isolated ion channels before, it was subjected in this work to extensive screening on a panel of 17 ion channels: nine cloned voltage-gated ion channels (mammalian Nav1.1–Nav1.8 and insect Para) and eight cloned voltage-gated potassium channels (mammalian Kv1.1–Kv1.6, hERG and insect ShakerIR) expressed in Xenopus laevis oocytes using two-electrode voltage-clamp technique. All tested sodium channel subtypes are insensitive to gambierol concentrations up to 10 µM. In contrast, Kv1.2 is the most sensitive voltage-gated potassium channel subtype with almost full block (>97%) and an half maximal inhibitory concentration (IC50) of 34.5 nM. To the best of our knowledge, this is the first study where the selectivity of gambierol is tested on isolated voltage-gated ion channels. Therefore, these results lead to a better understanding of gambierol and its possible role in CFP and they may also be useful in the development of more effective treatments.

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