Acupuncture seems so mysterious. How can sticking needles into the body cause physical changes, such as pain or nausea relief or an enhanced immune system?

Researchers working on mice say they have a clue. They have identified a molecule, called adenosine, that seems to be involved in generating the physical effects seen in acupuncture. Adenosine is a natural substance known for helping to regulate sleep and for its anti-inflammatory properties. It also acts as a natural painkiller, developing in the body after an injury to stop nerve signals that are screaming “pain!” But scientists at the University of Rochester Medical Center found that the substance is also active in deeper tissues in the body that are affected by acupuncture.

In the experiment, researchers performed acupuncture on mice that had discomfort in one paw. The mice received a 30-minute acupuncture treatment at a point near the knee. The study showed that in mice with normal functioning levels of adenosine, acupuncture reduced pain by about two-thirds. During and after the treatment, the level of adenosine in the tissues near the needles was 24 times greater than before the treatment. But  the treatment had no effect on mice that lacked the adenosine receptor.

The researchers also tested the effects of a cancer drug called deoxycoformycin that makes it harder for the tissue to remove adenosine. Adding this drug significantly boosted the effects of the acupuncture.

“Acupuncture has been a mainstay of medical treatment in certain parts of the world for 4,000 years, but because it has not been understood completely, many people have remained skeptical,” the lead author of the study, Maiken Nedergaard, a neuroscientist, said in a news release. “In this work, we provide information about one physical mechanism through which acupuncture reduces pain in the body.”

The study was published online this week in the journal Nature Neuroscience.

— Shari Roan

Photo credit: Advanced Cell Technology Inc.