Cone Snail
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The cone snails (Conidae) are marine snails found in coral reefs.
They can grow up to 23 cm and are found in tropical waters. There are about 500 different types of cone snails. All cone snails have characteristic sharp fangs that act like harpoons. The venom can be strong enough to kill a human being; 30 deaths have been recorded. The harpoon-like stinger of the cone snail can penetrate gloves or even wetsuits, so people should avoid handling them. Indeed, the venom of the most dangerous species is so toxic that they are known as "Cigarette Snails," because the victim will have only enough time to smoke a cigarette before perishing.
The venom of cone snails varies widely from one species of cone snail to another. The toxins in these various venoms are called conotoxins. These are various peptides, targeting each a specific nerve channel or receptor. This venom also contains a pain-reducing component, first pacifying the victim, before immobilising and then killing it.
Conus-geographicus.jpg
The venom of some cone snails, like the magician cone snail, show much promise for a non-addictive pain relief 1000 times as powerful as, and a possible replacement for morphine. Cone snails are the only known animals that produce D isomer amino acids. This opens the prospect for a number of potent pharmaceuticals, such as AVC1, isolated from the Australian cone shell Conus victoriae. This has proved very effective in treating post-surgical and neuropathic pain, even accelerating recovery from nerve injury. The first painkiller, derived from cone snail toxins, was approved by the U.S. Food and Drug Administration in December 2004. Other drugs are in clinical and preclinical trials.
Some cone snail venom contains tetrodotoxin, which is the same paralytic neurotoxin as that of the pufferfish and the blue-ringed octopus.
Symptoms of a cone snail sting include intense pain, swelling, numbness and tingling. Symptoms can start immediately or can be delayed in onset for days. Severe cases involved muscle paralysis, changes in vision and respiratory failure that can lead to death.
There is even more to come. Some compound of the cone snail's toxin may be used in the treatment of a number of illnesses such as Alzheimer's disease, Parkinson's disease and epilepsy.
External links
- Cone snail and conotoxins page (http://grimwade.biochem.unimelb.edu.au/cone/index1.html)
- One slip, and you’re dead... (http://www.nature.com/nsu/040621/040621-6.html) (Nature news article)