03 June 2010
Natural born pain killers
Venom from cone snails offers hope for people in chronic pain. Photo: Carla Gottgens.
Professor David Adams. Photo: Carla Gottgens.
For the one in five Australians of working age suffering from serious chronic pain, the options are strictly limited. There’s morphine and... well, there’s morphine.
But research using one of the most powerful toxins in the natural world - the venom of marine cone snails - offers hope for a pain-free and addiction-free future.
"The big problems with morphine are its addictiveness and the fact that, over time, people develop a tolerance to it," Professor David Adams says.
"We don’t have that problem with the peptides derived from cone snail venom. People don’t develop tolerance and they don’t get hooked.
"There’s also a wide safety margin. With morphine, there’s little room for error - you overdose, you’re likely to die. But with peptides, there’ll be some side-effects but you will survive."
Adams, the Director of the RMIT Health Innovations Research Institute, leads the University’s investigations into venom peptides, the cocktail of agents in cone snail venom that paralyses prey.
His team focuses on isolating peptides that target particular receptors in pain pathways in a bid to find new treatments for chronic and neuropathic pain.
"Pharmaceutical companies spend billions trying to synthesise small molecules but in cone snails, nature’s already done the work for us," he says.
"The peptides in cone snail venom have exquisite selectivity. The challenge we have is to understand the pathways and the targets, and put them to therapeutic use."
Worldwide, there are more than 700 species of cone snails, with about two-thirds found in the Great Barrier Reef. Each species’ venom contains between 100 and 200 unique peptides but fewer than 100 have been classified.
"There’s enormous potential in this field for discovery," Adams says. "We’re focused on the peptides that target pain pathways but there are many other possibilities, such as treatments for cardio-vascular conditions."
Backed by a $1.4 million Australian Research Council grant, Adams and his team work with one of the world’s leading cone snail experts, Professor Frank Mari at Florida Atlantic University.
The collaboration with Mari means RMIT can now broaden its investigations beyond Australian species. The team also works with researchers in the University of Calgary and a group based in Belgium, sharing their raw cone snail venom material, which is then synthesised for analysis.
While it’s been long known that cone snails are dangerous, and can even kill, the first studies of the venom in Australian species were conducted only in the late 1960s.
"In some of the old medical reports where people had been stung by cone snails, they didn’t actually feel pain - most of them died because of respiratory paralysis," Adams says.
"There was clearly a powerful toxin there but it took until the 1980s before medical researchers started to look into cone snail venom for therapeutic use.
"So far, just one peptide pain-killing drug has been approved for use in the US. But when you consider there are more than 100,000 unique peptides that we still know nothing about, the possibilities in this field are just breathtaking."