ROLE OF OPIOID-PEPTIDES OF RATS NUCLEUS-RETICULARIS PARAGIGANTOCELLULARIS LATERALIS (RPGL) IN ACUPUNCTURE ANALGESIA

The present study was to investigate the role of the RPGL and its endo genous opioid peptides in acupuncture analgesia (AA) using techniques of brain stimulation and lesion, microinjection, push-pull perfusion r adioimmunoassay (RIA). The results showed electrical stimulation of th e RPGL could increase the pain threshold and enhance the effect of AA, whereas lesion of the RPGL reduce the effect of AA. Microinjection of naloxone (5ug/0.5ul/2min) into the RPGL could partially reverse the e ffect of AA and the reversal effect of naloxone was dose-dependent. Th e release of leu-enkephalin (LEK) and B-endorphin (B-EP) from the RPGL in the electrical acupuncture (EA) group was significantly higher tha n that in the control group (P<0.05). There were positive correlations between the changes of release of LEK, B-EP and the increase of pain threshold. The results mentioned above imply that the RPGL plays an im portant role in AA. The activation of the RPGL and the endogenous opio id peptides within it produce an advantageous effect on AA.