Production of a Purified Marine Neurotoxin and Demonstration of its Binding Affinity to Ion Channel Receptors

Ciguatera is a tropical fish-borne disease in which both a lipid soluble (ciguatoxin) and water soluble (maitotoxin) toxin have been implicated. The determination of toxin structure, cell binding characteristics, and sensitive assays are all dependent on an increased supply of toxins. In order to increase our production of toxin we developed a mass culture technique using a Gambierdiscus toxicus dinoflagellate strain. The mode of action of many of the marine neurotoxin such as ciguatoxin and brevetoxin have been reported to involve a common binding site on sodium channels. An in vitro binding study using a rat brain synaptosome preparation demonstrated that brevetoxin binds with a high affinity and specificity, our results demonstrate that ciguatoxin does affect the binding of brevetoxin to synaptosomes. Therefore, our results lend further support to the conclusion that maitotoxin and ciguatoxin possess different pharmacological modes of action. Keywords: neurotoxins; Marine toxins; Binding sites.