Electrophysiological Evaluation of Pacific Oyster (Crassostrea gigas) Sensitivity to Saxitoxin and Tetrodotoxin

Type Article
Date 2021-07
Language English
Author(s) Boullot Floriane1, 2, Fabioux CarolineORCID2, Hégaret Helene4, Boudry PierreORCID3, Soudant Philippe4, Benoit EvelyneORCID1
Affiliation(s) 1 : Service d’Ingénierie Moléculaire Pour la Santé (SIMoS), Département Médicaments et Technologies Pour la Santé (DMTS), Institut des Sciences du Vivant Frédéric Joliot, Université Paris-Saclay, CEA, ERL CNRS/CEA 9004, 91191 Gif-sur-Yvette, France
2 : Laboratoire des Sciences de l’Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France
3 : Centre Ifremer Bretagne, Ifremer, UMR 6539 (LEMAR) CNRS/UBO/IRD/Ifremer, ZI de la Pointe du Diable, CS 10070, 29280 Plouzané, France
4 : Laboratoire des Sciences de l’Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France
Source Marine Drugs (1660-3397) (MDPI AG), 2021-07 , Vol. 19 , N. 7 , P. 380 (17p.)
DOI 10.3390/md19070380
Note This article belongs to the Special Issue Marine Biotoxins
Keyword(s) Crassostrea gigas, compound nerve action potential, Alexandrium minutum, paralytic shellfish toxins
Abstract

Pacific oysters (Crassostrea gigas) may bio-accumulate high levels of paralytic shellfish toxins (PST) during harmful algal blooms of the genus Alexandrium. These blooms regularly occur in coastal waters, affecting oyster health and marketability. The aim of our study was to analyse the PST-sensitivity of nerves of Pacific oysters in relation with toxin bio-accumulation. The results show that C. gigas nerves have micromolar range of saxitoxin (STX) sensitivity, thus providing intermediate STX sensitivity compared to other bivalve species. However, theses nerves were much less sensitive to tetrodotoxin. The STX-sensitivity of compound nerve action potential (CNAP) recorded from oysters experimentally fed with Alexandrium minutum (toxic-alga-exposed oysters), or Tisochrysis lutea, a non-toxic microalga (control oysters), revealed that oysters could be separated into STX-resistant and STX-sensitive categories, regardless of the diet. Moreover, the percentage of toxin-sensitive nerves was lower, and the STX concentration necessary to inhibit 50% of CNAP higher, in recently toxic-alga-exposed oysters than in control bivalves. However, no obvious correlation was observed between nerve sensitivity to STX and the STX content in oyster digestive glands. None of the nerves isolated from wild and farmed oysters was detected to be sensitive to tetrodotoxin. In conclusion, this study highlights the good potential of cerebrovisceral nerves of Pacific oysters for electrophysiological and pharmacological studies. In addition, this study shows, for the first time, that C. gigas nerves have micromolar range of STX sensitivity. The STX sensitivity decreases, at least temporary, upon recent oyster exposure to dinoflagellates producing PST under natural, but not experimental environment.

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How to cite 

Boullot Floriane, Fabioux Caroline, Hégaret Helene, Boudry Pierre, Soudant Philippe, Benoit Evelyne (2021). Electrophysiological Evaluation of Pacific Oyster (Crassostrea gigas) Sensitivity to Saxitoxin and Tetrodotoxin. Marine Drugs, 19(7), 380 (17p.). Publisher's official version : https://doi.org/10.3390/md19070380 , Open Access version : https://archimer.ifremer.fr/doc/00704/81561/