7. The Cone Snail - Natural Morphine
Cone snails (Conus magus) live natively in the Indian and Pacific Oceans, where they feed on small fish. The little defenceless and slow-looking snail is actually a vicious predator. Their prey is often much faster than they are, so rather than go into training, they've armed themselves. The snails fire a tooth which contains the venom at prey or enemies, just like a harpoon. The snails use potent neurotoxins in their venom to immobilise and capture their meals. The smaller species of snails produce a painful sting like a bee, but larger ones can be fatal - for any human who has been stung by a cone shell, the chance of mortality is 90 percent. These little snails produce hundreds of different conotoxins, each with its own specific molecular targets, making them one of the most exciting sources of potential new drugs. A single conotoxin will only bind with a single type of nerve ion-channel. This makes the conotoxins a very precise and effective tool for research. Neuroscientists can reach into this toxic tool chest and switch on or off the precise component of the nervous system they are studying. Scientists produced a synthetic peptide called Ziconotide capable of blocking pain inspired by one the of the snails conotoxin that paralyses prey. This drug is used to relieve chronic pain, and is 100 times as effective as morphine and because it targets different receptors to opiates it is unlikely to produce the same addiction response. There are also a few other cone snail toxins that have been transformed into potential pharmaceuticals to treat pain, addiction and cancer, awaiting the results of clinical trials.