Acupuncture had no effect in either group of mice if the needles were not rotated, suggesting that the tissues had to be physically damaged to release adenosine.
Nedergaard said that twisting the needles seems to cause enough damage to make cells release the painkilling chemical. This is then picked up by adenosine receptors on nearby nerves, which react by damping down pain. Further tests on the mice revealed that levels of adenosine surged 24-fold in the tissues around the acupuncture needles during and immediately after each session.
One of the longstanding mysteries surrounding acupuncture is why the technique only seems to alleviate pain if needles are inserted at specific points. Nedergaard believes that most of these acupuncture points are along major nerve tracks, and as such are parts of the body that have plenty of adenosine receptors.
‘GROWING UNDERSTANDING’
In a final experiment, Nedergaard’s team injected mice with a cancer drug that made it harder to remove adenosine from their tissues. The drug, called deoxycoformycin, boosted the effects of acupuncture dramatically, more than tripling how long the pain relief lasted.
“There is an attitude among some researchers that studying alternative medicine is unfashionable,” said Nedergaard. “Because it has not been understood completely, many people have remained skeptical.”
Although the study explains how acupuncture can alleviate pain, it sheds no light on the other health benefits that some practitioners believe the procedure can achieve.
Josephine Briggs, the director of the national center for complementary and alternative medicine at the US National Institutes of Health, said: “It’s clear that acupuncture may activate a number of different mechanisms ... It’s an interesting contribution to our growing understanding of the complex intervention which is acupuncture.”
RSS