A University of Michigan study provides evidence that acupuncture affects the brain’s long-term ability to regulate pain.

As reported in the Journal of NeuroImage, researchers at the UM Chronic Pain and Fatigue Research Center demonstrated that acupuncture increased the binding availability of mu-opoid receptors (MOR) in regions of the brain (amygdala, thalamus, cingulate, and insula) that process and dampen pain signals.

Current thinking is that Opioid painkillers, such as morphine, codeine and other medications work by binding to these opioid receptors in the brain and spinal cord.

Richard E. Harris, Ph.D., one of the researchers reports,  “The increased binding availability of these receptors was associated with reductions in pain. One implication of this research is that patients with chronic pain treated with acupuncture might be more responsive to opioid medications since the receptors seem to have more binding availability

The study participants included 20 women who had been diagnosed with fibromyalgia, a chronic pain condition, for at least a year, and experienced pain at least 50 percent of the time. During the study they agreed not to take any new medications for their fibromyalgia pain.

Patients had position emission tomography, or PET, scans of the brain during the first treatment and then repeated a month later after the eighth treatment.

Harris RE, Zubieta JK, Scott DJ, Napadow V, Gracely RH, and Clauw DJ.  Traditional Chinese Acupuncture and Placebo (Sham) Acupuncture Are Differentiated by Their Effects on µ-Opioid Receptors (MORs). (2009) in press Neuroimage.