Mechanisms of Acupuncture Regulation of Cardiovascular Function

Professor John Longhurst

Medicine, School of Medicine M.D., University of California, USA.

Acupuncture stimulates finely myelinated somatic sensory nerves.  We have focused on the cardiovascular consequences of acupuncture.  Manual and electroacupuncture (EA), especially low frequency EA similarly stimulate both Group III and IV somatic afferents to effectively regulate cardiovascular function.

Early studies showing that EA reverses demand-induced myocardial ischemia demonstrated that the underlying mechanism of EA was caused by decreased myocardial oxygen demand, primarily due to a reduction of elevated arterial blood pressure.  EA did not reduce blood pressure when pressure was within the normal range.  We therefore concentrated mainly on mechanisms contributing to  acupuncture’s hypotensive actions using experimental models of reflex sympathoexcitation as well as animal models and human subjects with sustained hypertension. 

EA lowers systolic and mean arterial pressure in approximately 70% of patients with mild to moderate hypertension. We found in experimental models that acupuncture effectively lowers reflex elevations in blood pressure through its actions in the hypothalamus, midbrain and medullary regions of the brainstem, especially in the rostral ventrolateral medulla. Several inhibitory neurotransmitter systems are involved, including opioids (β-endorphin and enkephalins) and gamma aminobutyric acid (GABA), among others. 

More recent data show that EA also modulates reflex-induced hypotension and bradycardia through the actions of GABA in the rostral and caudal ventrolateral medulla, two regions that regulate sympathetic outflow, and in the nucleus ambiguus through GABAergic and opioidergic mechanisms. Thus, acupuncture stimulation of somatic sensory nerves has the capacity to normalize blood pressure through the actions of a variety of neuromodulators in both pressor and depressor regions of the brain.