The researchers then measured blood hormone levels secreted by the hypothalamus pituitary adrenal (HPA) axis, which includes the hypothalamus, the pituitary gland and the adrenal gland. The interactions among these organs control reactions to stress and regulate digestion, the immune system, mood and emotions, sexuality and energy storage and expenditure.
They also measured levels of NPY, a peptide secreted by the sympathetic nervous system in rodents and humans. This system is involved in the "flight or fight" response to acute stress, resulting in constriction of blood flow to all parts of the body except the heart, lungs and brain (the organs most needed to react to danger). Chronic stress, however, can cause elevated blood pressure and cardiac disease.
"We found that electronic acupuncture blocks the chronic, stress-induced elevations of the HPA axis hormones and the sympathetic NPY pathway," Eshkevari says. She adds that the rats receiving the sham electronic acupuncture had elevation of the hormones similar to that of the stress-only animals.
Eshkevari says this research complements her earlier reported work that focused only on NPY. In that study, Eshkevari and her team found that NPY levels were reduced in the experimental group almost to the level of the control group, while the rats that were stressed and not treated with Zusanli acupuncture had high levels of NPY (Experimental Biology and Medicine Dec. 2011).
"Our growing body of evidence points to acupuncture's protective effect against the stress response," she continues. Eshkevari says additional research is needed to examine if acupuncture would be effective in reducing hormone levels after the animals are exposed to the stress of cold temperatures, and whether a similar observation can be made in humans.
|Contact: Karen Mallet|
Georgetown University Medical Center