Tetrodotoxin

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Fugu - Tetrodotoxin - Poster


Overview


Tetrodotoxin blocks action potentials in nerves by binding to the voltage-gated, fast sodium channels in nerve cell membranes, essentially preventing any affected nerve cells from firing by blocking the channels used in the process. The binding site of this toxin is located at the pore opening of the voltage-gated Na+ channel. Its name derives from Tetraodontiformes, the name of the order that includes the pufferfish, porcupinefish, ocean sunfish or mola, and triggerfish, several species of which carry the toxin. Although tetrodotoxin was discovered in these fish and found in several other animals (e.g., blue-ringed octopus, rough-skinned newt, and Naticidae) it is actually produced by certain symbiotic bacteria, such as Pseudoalteromonas tetraodonis, certain species of Pseudomonas and Vibrio, as well as some others that reside within these animals.

The Material Safety Data Sheet for tetrodotoxin lists the oral median lethal dose (LD50) for mice as 334 μg per kg.22 Assuming the lethal dose for humans is similar, 25 milligrams (0.000881 oz) of tetrodotoxin would be expected to kill a 75 kg (170 lb) person. The amount needed to reach a lethal dose by injection is much smaller, 8 μg per kg, or a little over one-half milligram (0.00002 oz) to kill a 75 kg (170 lb) person.


Death by Puffer fish


  • 1975 - Bando Mitsugoro VIII died after eating fugu fish Tetrodotoxin poisons after seven hours of paralysis and convulsions, was one of Japan's most revered Kabuki actors.

References


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