Tuesday, June 1, 2010
From today's Wall Street Journal:
The compound adenosine is key to acupuncture's effectiveness, according to a study in Nature Neuroscience. Despite acupuncture's 4,000-year history, little is known about the biological pathways that enable carefully placed needles to relieve pain in many patients. Researchers mimicked acupuncture in mice by placing and gradually rotating a needle at a point just below the knee, for 30 minutes. Levels of adenosine, a neurotransmitter, rose 24-fold in the tissue fluid surrounding the needle. Mice injected with an inflammatory substance in their paws and given acupuncture displayed fewer pain symptoms than mice that didn't get acupuncture. But mice genetically engineered to lack a certain adenosine receptor didn't benefit from the acupuncture session at all—further evidence of adenosine's role. Blocking enzymes that break down adenosine made the acupuncture much more effective, tripling the level of adenosine near the needle and extending pain relief from about one hour to about three hours.
Caveat: As with any animal study, it's far from certain that these findings can be replicated in humans.