PHARMACOLOGICAL ACTIONS OF THE MARINE TOXINS CIGUATOXIN AND MAITOTOXIN ISOLATED FROM POISONOUS FISH

Ciguatoxin and maitotoxin isolated from poisonous fish and toxic dinoflagellates exhibited a powerful excitatory effect on smooth and cardiac muscle. The ciguatoxin-induced excitatory action is due to an increase in Na+ permeability of tetrodotoxin sensitive Na channels, while the maitotoxin-induced excitatory effect is caused by an increased Ca2+ permeability of the cell membrane.