Research in acupuncture at Samueli Center investigates mechanisms that underlie the effect of acupuncture on blood pressure. Dr. John Longhurst's laboratory is defining areas in the brain the process nerve signal input received during electroacupuncture.
During needle stimulation, we have shown that sensory nerves located beneath acupoints send information to several regions in the brain that receive input from many other acupoints, as well as from visceral organs such as the stomach and gallbladder. For example, a balloon is distended in the stomach or an inflammatory chemical is applied to the gallbladder to simulate food ingestion or inflammation. During stimulation of these visceral organs, blood pressure is elevated. Nerves located under acupuncture points on the arm or leg that are stimulated by the acpuncture suppress the increased pressure, in part, because they cause the local release of endorphins and enkephalins, part of the brain's opioid system.
These studies employ anatomical, pharmacological and physiological techniques to monitor activity in neurons in several areas of the brain and to dissect the neurotransmitter chemical signals, like opioids, that are responsible for the acupuncture-cardiovascular effect. We now know that these endorphins and enkephalins reduce the increased activity that is generated during stimulation of the visceral organ. Thus, these studies provide new information about how acupuncture works to lower blood pressure.