Orphanin FQ(OFQ

also named "nociceptin")

a new member of the opioid peptides f amily

was discovered in 1995. The relationship between OFQ and pain modulation or acupuncture analgesia was investigated in our research group. It was found t hat icv injection of OFQ could attenuate opioid analgesia and acupuncture analge sia

but OFQ in spinal cord produced significant analgesia

and had synergic eff ect with endomorphin induced analgesia. OFQ in the brain could inhibit the activ ities of opioid system

including release of the peptides and expression of the peptides and their receptors. But in the spinal cord OFQ would increase the rele ase of endomorphin. Electroacupuncture could increase the activities of OFQ syst em in the brain

which might be one of mechanisms of incomplete analgesia by acu puncture. So the effect of acupuncture analgesia would be enhanced through the i nhibition of OFQ system in the brain. In the present studies

it was also found that some OFQ like immunoreactive neurons in the brain and the spinal cord coul d express OFQ receptor (self receptor)

and NC NH 2

one kind of new antagoni st of OFQ receptor

might be indicated an agonist. According to these above results

it is suggested that OFQ is a new importan t factor involving acupuncture analgesia.