There have been a number of scientific studies that have researched the effects of acupuncture analgesia.  Some studies have found that chemical mediators were involved in this kind of acupuncture.

In Japan, there was animal experimentation conducted to find various results.  It was suggested that there is a possible role of the centromedian nucleus of the thalamus in analgesic acupuncture.

Some of the analgesic effects of acupuncture include the actions of endogenous pain inhibitory mechanisms including the endogenous opioids, diffuse noxious inhibitory controls, and receptors and afferent pathways for acupuncture stimulation.

The effects of acupuncture anesthesia and analgesics have been well clarified by experimental studies.  The overall participation of opioids and their receptors have been widely accepted.  However, this is inadequate for explaining the acupuncture action on patients suffering pain.

The reason for this is because the stimulus conditions in animal experiments in Japan are much stronger than those that are used in clinical situations.  There is much more research needed to see the true effect that analgesic acupuncture has on pain suffered by humans before anything can be clarified.  The nature and development of acupoints remain as an issue that needs to be resolved by further acupuncture research over the next few years.