Public Release: 

Snail venom heralds new era of pain treatment

University of Melbourne

Australian scientists have taken out a full patent on a novel compound from a toxic marine snail that could be a godsend to sufferers of chronic pain.

The compound from a species of cone shell, a beautiful, but often deadly type of mollusc found on the Great Barrier Reef, could hold the key to a new era of powerful drugs to treat chronic pain common in diseases such as cancer, AIDS and arthritis. In laboratory studies the drug, known as ACV1, is more powerful and longer lasting than morphine. And, unlike morphine, it is not addictive and lacks the side-effects of morphine, namely constipation and respiratory depression.

The team from the University of Melbourne, made ACV1 from the venom of a cone shell for biological testing. They will make further information available this week at the International Society for Toxinology congress being held in Cairns (8-12 July), and formally announce the discovery the following week at the Venoms to Drugs conference on Heron Island (14-19 July).

"We have advanced the research to a stage where we now seek a commercial partner to take this novel compound to human trials and develop it as a treatment for chronic pain," says Associate Professor Bruce Livett, team leader and Reader in The Department of Biochemistry and Molecular Biology at the University of Melbourne.

"More than 60 percent of the community will suffer from chronic pain sometime in their life. The global market for drugs to treat for this form of pain is in excess of $1 billion and the medical profession is crying out for alternative drug treatments," he says.

"There are potential wider applications for this compound, including pain relief from sports injury and infection, for example shingles. In tests on rats it has also been found to accelerate wound healing where nerve damage has occurred."

ACV1 treats pain by blocking the transmission of pain along our peripheral nervous system - the nervous system that runs throughout our body and transmits the pain you feel if, for example, you cut yourself, break a bone or suffer internal injuries.

Cone shells are found in reefs around the world. They are the hunters of their realm, using a modified mouth-part to harpoon their prey and inject into them a paralyzing toxin. About 30 humans have died from their sting.

Despite this potential deadly characteristic, shell collectors have been known to pay more than $1,000 for a good specimen.

"Not all species will kill a human. The venom of some species obviously has useful properties. There are a number of research groups around the world, including ourselves, going through the exacting process of assaying venom components from each species to find those that may have useful pharmacological properties," says Livett.

"One company already has a drug from a coneshell toxin (conotoxin) that has reached the final stages of human trials, but when administered to some patients it has given unwanted side-effects that include raised blood pressure," he says.

"ACV1 acts on a different class of pain receptors to these drugs and is unlikely to exhibit the same side-effects.

"ACV1 is also a tiny molecule compared to the competing conotoxin drugs making it easier and cheaper to synthesize. Competing drugs also need to be injected into the spinal column. ACV1 can be injected into the muscle or fat layer of patients making it available to a wider group of patients and an advantage when recruiting patients for clinical trials.

"Cone shells provide a largely untapped source of novel compounds that are being used to develop human pharmaceuticals for everything from pain to epilepsy," he says.

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Website: http://grimwade.biochem.unimelb.edu.au/cone/index1.html

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