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Office of Neuroscience Research > WUSTL Neuroscience News > Non-opioid drug relieves pain in mice, targets immune cells

Non-opioid drug relieves pain in mice, targets immune cells



From the WashU School of Medicine News

Faced with the epidemic of opioid addiction, researchers have been charged with finding other strategies to treat pain. Their efforts largely have focused on nerve cells that transmit pain signals to the spinal cord and brain. But new research, led by scientists at Washington University School of Medicine in St. Louis, shows that targeting receptors on immune cells may be more effective, particularly for chronic pain.

Recently, a non-opioid, investigational drug called EMA401 has shown promise as a treatment for lingering nerve pain following shingles infection. While trying to understand how that drug helped control pain, the Washington University research team was surprised to find that it doesn’t hit nerve cells; rather, it targets a receptor on immune cells.

Their findings are published July 2 in The Journal of Neuroscience.

“We are in dire need of good pain-killing drugs, particularly non-opioid drugs,” said principal investigator D.P. Mohapatra, PhD, an associate professor in anesthesiology. “Generally, scientists have the understanding that targets for treating pain must be within the nervous system. It turns out that the target here is not on nerve cells, but on immune cells called macrophages.”

The investigational drug inhibits the angiotensin II type 2 receptor that is targeted by medications that lower blood pressure. Angiotensin is a hormone that causes blood vessels to constrict, increasing blood pressure.

This drug was thought to work by interacting with the type 2 receptor on nerve cells — the same cells that carry pain signals. But when Mohapatra and his colleagues at the Washington University Pain Center looked more closely, they found that theory was wrong.

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