Tetrodotoxin (TTX)

Tetrodotoxin (TTX) is a poison that is produced by most commonly puffer fish as well as many other organisms. It is a virulent poison that acts by blocking the impulses of nerves along axon terminals. Which ultimately can lead a victim to die from paralysis. The specific channels that this toxin blocks is the sodium ion channels. TTX is larger than sodium, which is why it blocks the channels so easily. To give some perspective, sodium binds in the channels in nanoseconds whereas TTX is bound for tens of seconds in the channels.

There are a couple different ways for humans to get harmful doses of TTX one of the common ways of receiving a lethal dose of TTX is by digestion. In Japan puffer fish is a delicacy call fugu. Chefs prepare this dish with special certifications by the government so they do not prepare toxic flesh, liver, and gonads. But despite the precautions many cases of TTX poisoning are from people ingesting fugu (puffer fish).  Another way to get TTX poisoning is by coming into contact with the skin of Atelopid frogs, and certain newts, sea slugs, as well as being bitten by a certain gastropod mollusks. It has been verified that 1-2 mg of purified TTX can be lethal to a human.

Pufferfish or Tetraodontidae is a carnivore that contains the TTX toxin as mentioned above which makes the fish foul tasting and often is deadly to the predator that ate the pufferfish. To humans, pufferfish are approximately 1,200 times more poisonous than cyanide. And there is approximately enough TTX toxins in one pufferfish to kill about 30 humans. There is no known antidote for TTX poisoning only symptoms including numbing of the mouth and its surrounding areas, nausea and numbness.

I find that animals that are extremely toxic to any organisms are extremely interesting and I would like to find out more about this specific toxin and as to why they are in specific animals. In my presentation I would like to discuss more of the animal groups that the Tetrodotoxin occurs in.

http://emedicine.medscape.com/article/818763-overview

http://animals.nationalgeographic.com/animals/fish/pufferfish/

http://www.life.umd.edu/grad/mlfsc/zctsim/ionchannel.html 

http://www.thecephalopodpage.org/bluering2.php