U. scientists find new painkiller target

Researchers from the University of Utah have discovered a new target for painkillers, opening new ways to treat persistent nerve pain.

J. Michael McIntosh, and colleagues from the U. and Wake Forest University, North Carolina, published a study in the online edition of "Proceedings of the National Academy of Sciences" outlining the discovery. McIntosh has been involved in discoveries of new painkiller medicines derived from poisons in marine cone snails.

McIntosh is a research professor of biology and research director as well as a professor in the U.'s Department of Psychiatry.

The new discovery is important for several reasons, including finding a previously unsuspected molecular target for painkillers. The molecule that is the target goes by a mouthful: "alpha9alpha10 nicotinic acetylcholine receptors."

McIntosh told the Deseret Morning News that humans experience pain in complex ways. Although a number of painkillers are available, "many of them work by the same mechanism."

"The problem is that pain is often incompletely treated by existing medications," he added. Researchers want to find more medicines to fully treat pain.

"We have the good fortune of working with our collaborators, the cone snails, who produce a rich variety of (poisonous) compounds," he said. The marine snails use venom to paralyze prey.

One of the compounds that the U. team studied recently "worked on not only a new target, but was also an analgesic as well," he said. Analgesics are painkillers.

The painkiller locks into a nicotine receptor, although it is not a receptor that was previously known as being involved in pain, he said.

All that was previously known about the molecule is that it helped in hearing. But it is also active elsewhere in the body, and is now shown to play a role involving pain.

The pain involved is called neuropathic pain. "That's pain that develops as a result of injury to a nerve," he said.

It is a fairly common type of discomfort that often develops because of injury to the nerve from causes like diabetes or trauma. Shingles, resulting from earlier cases of chicken pox, involves nerve injury too.

People with cancer also may experience this type of pain, either from the cancer itself or chemotherapy, he said.