Lancet. 1983 Dec; 2(8364): 1394-6.
Acupuncture relief of chronic pain syndrome correlates with increased plasma met-enkephalin concentrations.
In twenty patients with chronic pain syndrome, acupuncture treatment resulted in significant improvement of both pain and psychiatric symptoms and higher plasma concentrations of metenkephalin. Plasma beta-endorphin concentrations were unchanged. The degree of symptom relief was correlated with the increase in plasma met-enkephalin.