Quote:
Evidence for Endorphins in Acupuncture Analgesia (Pages 16-17)
The other early naloxone* study was by Pomeranz and Chiu(1) In awake mice; they used the mouse squeak latency paradigm and gave EA [Electro-Acupuncture] at LI.4. Numerous control groups were used in this latter experiment in an attempt to pick out some of the possible artifacts. Each group received one of the following treatments: EA alone, EA plus saline, EA plus i.v. naloxone, Sham EA in a non-acupuncture point, naloxone alone, saline alone, or no treatment at all (just handling, restraint, and repeated pain testing.) The results were unequivocal; naloxone completely blocked AA; sham EA produced no effect; and naloxone alone produced very little hyperalgesia (not enough to explain reduction of AA by subtraction.) Moreover, the results in mice and in humans indicated, first, that AA was not a psychological effect and secondly, that AA was truly blocked by naloxone. In a later study, Cheng and Pomeranz(2) produced a dose-response curve for naloxone and found that increasing doses produced increasing blockade.
*Naloxone is an endorphin antagonist. Researchers were able to identify endorphin production as one of the mechanisms for acupuncture analgesia by showing that naloxone blocks AA. Furthermore, it was discovered that Naloxone only prevents AA from initiating, and does not negate AA that has already been administered.