Puffer fish, poison from

Other Lethal Agents. There are a number of substances, many found in nature, which are known to be more toxic than nerve agents (6). None has been weaponized. Examples of these toxic natural products include shellfish poison, isolated from toxic clams puffer fish poison, isolated from the viscera of the puffer fish the active principle of curare "heart poisons" of the digitaUs type the active principle of the sea cucumber active principles of snake venom and the protein ricin, obtained from castor beans (See Castor oil). 

Kanchanapongkul, J. and Tantraphon, W., Pelagic paralysis from puffer fish poisoning, J. Med. Assoc. Thai., 76, 5, 285, 1993. 

CDC (1996) Tetrodotoxin poisoning associated with eating puffer fish transported from Japan-Cali-fornia. Morbidity and Mortality Weekly Report 45 389-391. 

No reliable incidence data exist for tetrodotoxin poisoning. The most extensive data on tetrodo-toxin poisoning comes from Japan where 6386 cases of puffer fish poisoning were reported during the 78-year-period 1886-1963 (59.4% were fatal) [134, 135]. If the average population during this time is assumed to have been approximately 60,000,000, this implies a minimum incidence of... 

The puffer fish is probably the best known neurotoxic fish. Several related species of fish, as well as other marine life, such as some frogs, starfish, octopus, and others, contain tetrodotoxin. Many people consider this fish a delicacy despite the occasional death from poor preparation. Tetrodotoxin is heat stable but water soluble, so careful preparation is necessary to limit neurological effects. Symptoms of poisoning include a rapid onset of numbness in the lips and mouth, which then extends to the fingers and toes, followed by general weakness, dizziness, and respiratory failure, leading to death. The mechanism of action is similar to that of saxitoxin and affects sodium channel permeability. 

The neurotoxin, tetrodotoxin, a highly potent poison from the puffer fish, blocks the conduction of nerve impulses along axons and so leads to respiratory paralysis by binding very tightly to the Na+ channel and blocking its action. 

Tetrodotoxin, a complex natural product containing several six-membered rings joined together, is a poison isolated from the ovaries and liver of the puffer fish, so named because the fish inflates itself into a ball when alarmed. Eating fish tainted with trace amounts of this potent toxin results in weakness, paralysis, and eventually death. One step in the synthesis of tetrodotoxin involves forming a six-membered ring by a Diels-Alder reaction. 

Like the acetylcholine receptor channel, the sodium channel also was purified on the basis of its ability to bind a specific neurotoxin. Tetrodotoxin, an organic compound isolated from the puffer fish, binds to sodium channels with great avidity (K nM). The lethal dose of this poison for an adult human being is about 10 ng. The sodium channel was first purified from the electric organ of electric eel, which is a rich source of the protein forming this channel. The isolated protein is a single chain of 260 kd. 

That nature is not benign, indeed that it can be extremely deadly, is another lesson to take away from this section. While chemists have been successful in creating some highly lethal agents, none of these quite matches the likes of botulinum toxin, cobra venom or the poison in puffer fish (tetrodotoxin). 

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