A cellular target for the lipophilic toxins from Karenia brevisulcata

Crude lipophilic toxin from Karenia brevisulcata has been shown to be toxic to mammalian neuroblastoma (Neuro2A) cells in culture. This toxicity is partially antagonised by the addition of saxitoxin. The dose–response curves of saxitoxin acting to antagonise the action of K. brevisulcata toxin and of brevetoxin were examined and they displayed similar EC50 values. These results suggest that at least some of the effect on Neuro2A cells of the lipophilic toxicity found in K. brevisulcata results from an interaction with the mammalian voltage-dependent sodium channel.