[Effect of anti-opioid peptide sera on oxytocin-induced enhancement of electroacupuncture analgesia].

The effects of intracerebroventricular injection of Anti-opioid peptide sera on oxytocin-induced enhancement of electroacupuncture (EA) analgesia were observed in this study. It was found that injection of anti-beta-endorphin serum (AEPS) alone could attenuate EA analgesia in rats. Injection of AEPS prior to intraventricular injection of oxytocin could not block the enhancement of EA analgesia by oxytocin. The antidynorphin A1-13 serum (ADYNS) alone could also reduce the EA analgesia, whereas injection of ADYNS prior to injection of oxytocin could potentiate the enhancement of EA analgesia by oxytocin. However, neither the anti-methionine enkephalin serum nor the anti-leucine enkephalin exerted any effect on the enhancement of EA analgesia by oxytocin. The above results showed that the dynorphin attenuate oxytocin-induced enhancement of EA analgesia, but Beta-endorphin and enkephalin do not affect this role of oxytocin. These data suggest the enhancement of EA analgesia by oxytocin is not dependent upon the endogenous pioid peptides in brain.