Multiple sodium channel isoforms mediate the pathological effects of Pacific ciguatoxin-1

Marco C. Inserra, Mathilde R. Israel, Ashlee Caldwell, Joel Castro, Jennifer R. Deuis, Andrea M. Harrington, Angelo Keramidas, Sonia Garcia-Caraballo, Jessica Maddern, Andelain Erickson, Luke Grundy, Grigori Y. Rychkov, Katharina Zimmermann, Richard J. Lewis, Stuart M. Brierley, Irina Vetter

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42 Citations (Scopus)

Abstract

Human intoxication with the seafood poison ciguatoxin, a dinoflagellate polyether that activates voltage-gated sodium channels (Na V), causes ciguatera, a disease characterised by gastrointestinal and neurological disturbances. We assessed the activity of the most potent congener, Pacific ciguatoxin-1 (P-CTX-1), on Na V 1.1-1.9 using imaging and electrophysiological approaches. Although P-CTX-1 is essentially a non-selective Na V toxin and shifted the voltage-dependence of activation to more hyperpolarising potentials at all Na V subtypes, an increase in the inactivation time constant was observed only at Na V 1.8, while the slope factor of the conductance-voltage curves was significantly increased for Na V 1.7 and peak current was significantly increased for Na V 1.6. Accordingly, P-CTX-1-induced visceral and cutaneous pain behaviours were significantly decreased after pharmacological inhibition of Na V 1.8 and the tetrodotoxin-sensitive isoforms Na V 1.7 and Na V 1.6, respectively. The contribution of these isoforms to excitability of peripheral C- and A-fibre sensory neurons, confirmed using murine skin and visceral single-fibre recordings, reflects the expression pattern of Na V isoforms in peripheral sensory neurons and their contribution to membrane depolarisation, action potential initiation and propagation.

Original languageEnglish
Article number42810
JournalScientific reports
Volume7
DOIs
Publication statusPublished or Issued - 22 Feb 2017

ASJC Scopus subject areas

  • General

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