By GREG LAVINE
Tuesday, November 21, 2006
The cone snails are at it again.
University of Utah researchers have harvested yet another substance from cone snail venom that holds promise in treating pain in humans. The findings appeared in Tuesday's edition of the journal Proceedings of the National Academy of Sciences.
The new substance could one day be found in pharmacies next to other cone snail-inspired compounds, such as Prialt, a pain relief treatment for terminal cancer patients.
J. Michael McIntosh, a U. researcher and study author, said the ongoing research into the various cone snail venoms has yielded a potential drug target for those suffering from nerve damage that may come as a result of diabetes and other problems. About 8 percent of people around the world suffer from what is known as neuropathic pain.
"Our hope is that by identifying new mechanisms for treating pain," said McIntosh, who was involved in the early work that led to Prialt, "we'll have another weapon in the arsenal to be able to treat pain."
In this case, a U. team isolated part of the venom of the worm-hunting Conus regius snail, found in waters ranging from coastal Georgia to Brazil. This particular compound seems to work in similar ways to another compound from a different cone snail that is now in clinical trials in Australia, he said.
For the Australian compound, researchers were unsure how the drug relieves pain. The new paper involving Conus regius suggests how previously known compounds and the U.'s compound work.
Neuropathic pain involves damage to the nervous system, which in turn triggers an immune response, such as inflammation, that only complicates the problem, he said. Part of the pain may result from the body's response to the immune cells.
The substance from Conus regius _ known as RgIA _ binds with a molecular target that is a nicotinic receptor, which is related to receptors that are activated by nicotine found in cigarette smoking. The receptor, once bound with the cone snail substance, seems to act to reduce pain. The specific receptors, called alpha9alpha10 nicotinic receptors, were not previously known to be involved in pain pathways.
To test the idea, the U. worked with researchers from the Wake Forest University School of Medicine, Winston-Salem, N.C. Michelle Vincler, a researcher at Wake Forest, tested the compound on mice with injuries similar to neuropathic pain.
When the substance was administered, the lab animals appeared to experience less pain, she said.
It could be about 10 years before any drugs related to this finding reach the market, McIntosh said. Like other such drugs, the manufacturer would create a synthetic compound to mimic the desired portion of the venom. Using the straight venom as a treatment from some cone snails could be deadly to humans.
Vincler, another study author, said this line of research also could benefit patients experiencing "phantom" pain from limbs that no longer exist, a growing problem with wounded soldiers coming back from Iraq. Even though the limb may be gone, there are associated intact nerves elsewhere in the body that are still active that create pain for the patient.
(Reach Greg Lavine at glavine(at)sltrib.com )
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