Abstract
The involvement of the dopaminergic system in acupuncture and morphine analgesia, measured by tail-flick test in rats has been investigated by observing the changes in acupuncture analgesia after treatment of a dopaminergic blocker, pimozide.
Acupuncture analgesia was completely antagonized by pimozide (4 mg/kg), while pimozide had no influence on the threshold of pain. Antagonistic action of pimozide on acupuncture analgesia was dose dependence.
Morphine analgesia was also completely antagonized by pimozide, and pimozide antagonized stimulation-produced analgesia caused by stimulation of acupuncture afferent pathways such as the dorsal periaqueductal central gray (PAG), the lateral septum and the anterior hypothalamus.
Pimozide did not antagonize the analgesia produced by stimulation of the ventral PAG which is one of the origins of acupuncture efferent pathways.
These data indicate that the dopaminergic system is involved in acupuncture afferent pathways.
