The pain eliminating effects of electroacupuncture have long been known however the analgesic mechanism involved has yet to be clarified. Recently with the discovery of endogenous analgesic peptids called endorphins much attention has been called to the relationship of these endorphins and the acupuncture analgesic effect. We examined to determine how electroacupuncture influences lumbar CSF endorphins and the so-called pain transmitting substance, Substance P.
In order to establish continuous lumbar anesthesia using tetracaine for 8 patients with gynecological lower abdominal diseases, a Tuohy needle was inserted from the lumbar area and a catheter inserted into the subarachnoidal space. In each case at the time of the insertion of the catheter 5ml. CSF was tapped. As pre-medication 0.01mg/kg. atropine sulfate, 2mg/kg secobarbiturate were administered. To maintain the analgesic effect hyperbaric or hypobaric tetracaine was administered according to individaul needs. For hypotension during the operations a plasma expander and when necessary ephedrine were administered by intramuscular or intravenous injection.
Immediately following the start of surgery acupuncture needles were inserted at right and left LI-4 and electrical stimulation at 3c/s, 1.0mA was administered for 50-120 minutes using the acupuncture therapy apparatus “TOKKI”. when the operation was finished, after 5ml. of CSF was again tapped through the catheter, the catheter was withdrawn as far as the subdural space and 20-40ml. physiological saline injected to combat the headache due to spinal fluid leakage. The test substance was immediately transferred to a siliconized test tube and cooled to a temperature of-80°C.
The RIA methods were used for the measurement of both endorphins and substance P. The crossover reaction between the β-endorphin and the βLPH was 50%. (Using the β-endorphin measuring kit manufactured by NEN).
The results in 7 of 8 examples showed a significant increase in CSF endorphins after electroacupuncture. It also became clear that there was a tendency for substance P levels to decrease due to electroacupuncture.