八肽胆囊收缩素(CCK-8)是一种典型的脑肠肽。在哺乳动物大脑皮层

丘脑和下丘脑某些区域内含有高浓度的 CCK-8。有人报道

将 CCK-8注入皮下大鼠对热板刺激的敏感程度下降

表明 CCK-8本身具有镇痛作用。也有人证明

给大鼠脊髓蛛网膜下腔和腹腔注射 CCK-8则The glass microelectrodes were introduced into nucleus parafascicularis(N.Pf)of thalamus in rats to record the discharges of pain-inhibition neurons(PIN) and pain-excitation neurons (PEN).The influences on discharges of PIN and PEN were observed after injection of chol(?)cystokinin octapeptide (CCK-8)

morphine or morphine and CCK-8.The results showed that: 1.CCK-8 per se produced no significant influence on the electric activities of PIN and PEN in N.Pf. 2.Morphine resulted in an excitation of the evoked response of PIN as well as an inhibition of the evoked response of PEN. 3.CCK-8 could anlagonize the electric activities of PIN and PEN caused by morphine. The results suggest that CCK-8 per se has no the analgesia.But CCK-8 could antagonize the effect of morphine analgesia.