强啡肽(Dynorphin)是1979年Goldstain等发现的一种内源性阿片肽

它在离体豚鼠回肠标本上具有强烈的阿片样活性。近年来

对于它在体内不同中枢部位的痛觉调制作用以及在电针镇痛中所起的作用日益引起人们的兴趣。在脊髓内

已有资Previous studies have shown that 2Hz but not lOOHz eiectroacupuncture (EA) stimulation released β-endorphin in PAG of the rat to induce analgesia. The present study was underlaken to see whether dynorphin plays a rle in PAG in mediating analgesia induced by low and high frequency EA. Injection of affinity purified dynorphin antibody (1:350

000 in RIA titer) 1μl into PAG blocked 2Hz EA analgesia almost completely

and 15Hz EA analgesia partly

leaving 100Hz EA analgesia intact. This blocking effect was totally disappeared when the antibody was diluted to 1/10 of its original concentration (1:35

000).Besides

injection of dynorphin into PAG through chronically implanted cannula showed no analgesic effect. The results suggest that the blockade of 2Hz EA analgesia by high titer drnorphin antibody injected into PAG may have been the result of cross reactivity of the antibody to other opioid peptides (such as β-endorphin

enkephalin

etc) released in the PAG area. The data also stress the importance of using antibodies of proper titer and concentration to exclude false positile or false negative conclusions in adopting the antibody microinjection techniques

as was repeatedly shown in the immunohistochemical studies.