Science Articles

Deadly Cone Snails (Conus) Harbour Painkillers of the Future

Wed, 8th Dec 2004

Barry Gibb

"I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me." Sir Isaac Newton (1642-1727) Snails. Yes, I know, it's hard to get excited. You think snail, you think, slime. You think slow, squidgy, meandering ball of wibbly-gloop. With eyes on stalks. Then again, you might just think of garlic. Snails are pathetic English garden munchers!

Or are they? Not all snails are born equal. Some snails are born with heightened killer instincts, roaming beneath the ocean's sConus_snail_harbours_nerve_toxinsurface, waiting, hunting for that one precious meal. And we're not talking limp lettuce - some snails are content with nothing less than bagging an entire fish! And should you, my friend, be unlucky enough to disturb one of these molluscs whilst out having a leisurely paddle, you could be well on your way to the great paddling pool in the sky.

Great White sharks are passé, welcome to the world of the genus, Conus

Collecting beautifully patterned Conus snails off the north east coast of Australia might sound like hard work, but it's not all boats, sun, fresh air and sea. Dr Bruce Livett of Melbourne University takes it all in his stride, though. For nearly a decade, he and his team of enthusiastic colleagues, students and friends have sought and studied these spectacular snails.

But why is a neuroscientist interested in these animals? Because, apart from their spectacularly patterned shells, these molluscs have a secret weapon - one that may revolutionise the treatment of pain. A typical poisonous snake might unleash a couple of different nerve toxins on its furry victim; but what the Conus lacks in speed, it more than makes up for in poison. These snails are positively brimming with nasties, often shoving around 50 individual toxic mini-proteins into their victim.

Your brain, under normal circumstances, is a finely honed thinking machine. The reason being that all of its nerves are able to function correctly, sending messages, receiving messages, processing the information and giving a pretty good output. If the brain is like an organic computer, then being stung by a Conus is a bit like pouring a pint of ale on a laptop. Fizz, bang, splutter, dead.

The reason is that each of the tiny proteins that make up the toxic cocktail are targeted at different parts of the nervous system: these snails don't just 'blow the bloody doors off' your brain, they terminate it from every conceivable angle!

Conus toxins are currently undergoing clinical trials to test their safety and efficacy in the relief of pain. (Image courtesy of the National Cancer Institute).But not all the components in the venom are deadly. Some turn out to be good for you. As they say "no pain, no gain". So what about the future of pain? Painkiller research can be riddled with problems: side-effects, dependency, efficacy. What about a painkiller that is as effective as morphine but has no apparent side-effects? The relatively few humans who have witnessed a death-by-snail have noted the absence of pain. And Bruce Livett and his team now know why.

One of the toxins in the sting of the Conus victoriae species, is a string of just 16 amino acids (the Lego units that make proteins). This tiny protein, ACV1, binds to bits of the brain that would normally allow us to feel pain, and shuts them down. What we potentially have here is a powerful new generation of analgesics. This new 'drug' has done very well in pre-clinical trials and is now undergoing toxicity tests prior to entering clinical trials, the rights for development into a drug having been bought by a company called Metabolic Pharmaceuticals.

So, spare a thought for our British, plant bound relatives. Maybe they deserve a little more respect. After all, with relatives like the Conus, you don't need to be pretty.

"It is perhaps a more fortunate destiny to have a taste for collecting shells than to be born a millionaire." Robert Louis Stevenson (1850-1894)

Subscribe Free

Related Content

Not working please enable javascript
Wellcome Trust
EPSRC
Powered by UKfast
STFC
Genetics Society
ipDTL