U.S. researchers say they’ve identified a protein in nerve cells that acts as a kind of gatekeeper for chronic pain.

This enzyme, called protein kinase G (PKG), is turned on and activated in response to injury or inflammation. Once activated, PKG triggers other processes that generate pain messages that are sent to the brain. As long as PKG is switched on, pain persists. Turning PKG off relieves pain.
"We’re very optimistic that this discovery and our continued research will ultimately lead to a novel approach to pain relief for the millions suffering from chronic pain," researcher Richard Ambron, professor of cell biology at Columbia University Medical Center in New York City, said in a prepared statement.
The study was published online in the journal Neuroscience and was expected to be in the August print issue.
Ambron and his colleague Ying-Ju Sung, an assistant professor of cell biology, have applied for a patent for the pathway that turns on PKG, as well as several molecules that inhibit it. They hope to develop a new class of drugs that target PKG in order to treat chronic pain.