大鼠蛛网膜下腔联合注射kappa受体激动剂和NMDA受体拮抗剂协同镇痛

以大鼠热辐射甩尾潜伏期为测痛指标，蛛网膜下腔（ｉｔ）联合注射非镇痛剂量的ｋａｐｐａ阿片受体激动剂强啡肽（ｄｙｎｏｒｐｈｉｎ，Ｄｙｎ）Ａ－（１－１３）５ｎｍｏｌ或Ｕ５０４８８Ｈ（ｔｒａｎｓ－（±）－３，４－ｄｉｃｈｌｏｒｏ－Ｎ－ｍｅｔｈｙｌ－［２－（１－ｐｙｒｒｏｌｉｄｉｎｙｌ）－ｃｙｃｌｏｈｅｘｙｌ］－ｂｅｎｚｅｎｅａｃｅｔａｍｉｄｅ）１００ｎｍｏｌ和Ｎ－ｍｅｔｈｙｌ－Ｄ－ａｓｐａｒｔａｔｅ（ＮＭＤＡ）受体拮抗剂ＤＬ－２－ａｍｉｎｏ－５－ｐｈｏｓｐｈｏｎｏｖａｌｅｒｉｃａｃｉｄ（ＡＰｖ）１０ｎｍｏｌ或ｋｙｎｕｒｅｎｉｃａｃｉｄ（ＫＹＮ）５０ｎｍｏｌ有显著的协同镇痛效应，其效应与ＮＭＤＡ受体拮抗剂呈一定量效关系。Ｋａｐｐａ阿片受体特异性拮抗剂ｎｏｒ－ｂｉｎａｌｔｏｒｐｈｉ－ｍｉｎｅ（ｎｏｒ－ＢＮＩ）１５ｎｍｏｌｉｔ可完全翻转ＤｙｎＡ－（１－１３）５ｎｍｏｌ和ＡＰｖ１０ｎｍｏｌ及Ｕ５０４８８Ｈ１００ｎｍｏｌ和ＫＹＮ５０ｎｍｏｌ的协同镇痛。说明协同作用是通过ｋａｐｐａ受体和谷氨酸能神经元之间的相互作用实现的。

INTRATHECAL CO-ADMINISTRATION OF KAPPA OPIOID RECEPTOR AGONISTS AND NMDA RECEPTOR ANTAGONISTS INDUCES SYNERGISTIC ANALGESIA IN RATS

It is reported that intrathecal(it)injection of low dose of dynorphin(Dyn)induces no analgesia while high dose of Dyn induces analgesia and might lead to hindlimb paralysis andloss of reflex via NMDA receptor.We hypothesized that NMDA receptor antagonists may reveal kappaanalgesic-potential of subliminal dose of Dyn. Twenty-four hours after intrathecal cannulation,tailflick latency was measured before and after it of drugs. Combination of Dyn A-(1-13)5 nmol orU50488H 100 nmol,a kappa receptor agonist with either DL-2-amino-5-phosphonovaleric acid(5 and10 nmol)or kynurenic acid(25 and 50 nmol)it induced synergistic analgesia,which was reversed bynor-binaltorphimine 15 nmol,a kappa receptor antagonist.It is concluded that kappa opioid receptoragonists and NMDA receptor antagonists synergistically induce analgesia via interaction with theirreceptors.