Effect of intracerebral microinjection of naloxone on acupuncture- and morphine-analgesia in the rabbit.

Although there are unequivocal evidences indicating the participation of endogenous opiate-like substances in acupuncture analgesia, their exact sites of action remain to be elucidated. From the results of localization studies by injecting minute amount of narcotic antagonist naloxone into discrete brain areas and assessing its effect on acupuncture analgesia in rabbits it is concluded that nuclei accumbens, amygdala, habenula and periaquaductal grey are the strategic sites for endogenous opioids to exert their analgesic effect. These brain areas are also of extreme importance for the realization of morphine analgesia.