野罂粟总生物碱镇痛作用与前列腺素及阿片受体的关系

目的研究野罂粟总生物碱(TAPN)的镇痛作用与前列腺素(PG s)、阿片受体的关系。方法采用小鼠热板法、扭体法、电刺激法3种致痛模型;测定3种不同致痛物乙酰胆碱(A ch)、醋酸(AA)和硫酸镁(M gSO4)致小鼠扭体反应后腹腔液中前列腺素E2(PGE2)水平及采用纳洛酮拮抗实验的方法,分析TAPN镇痛作用与前列腺素及阿片受体的关系,初步探讨TAPN的镇痛作用机制。结果TAPN对A ch、AA诱导的小鼠扭体反应的抑制作用明显强于对M gSO4的作用,且TAPN能明显降低小鼠AA致扭体后腹腔液中PGE2水平;在纳洛酮拮抗实验中,ip或侧脑室给药(icv)阿片受体拮抗剂纳洛酮均不能对抗TAPN的镇痛作用。结论TAPN抑制PG s的合成,可能是其发挥外周镇痛作用的主要机制;其中枢镇痛作用与阿片受体无关。

Relationship between analgesic effect of total alkaloids inPapaver nudicauleand prostaglandins with opium receptors

Objective To study the relationship between analgesic effect of total alkaloids in Papaver nudicaule(TAPN) and prostaglandins(PGs) with opium receptors.Methods The analgesic effect of TAPN was studied by hot-plate, writhing,electric-evoked methods of mice.The analgesic mechanisms of TAPN and PGs with opium receptors were studied by the writhing numbers induced by different substances(Ach,AA,MgSO_4),the PGE_2 level in celiac fluid in mice after treated by AA writhing test and the antagonistic experiment of Naloxone.Results The inhibitory effect of TAPN on the writhing induced by Ach and AA in mice was stronger than that induced by MgSO_4.TAPN could also lower the PGE_2 level in celiac fluid.In the antagonistic experiment of Naloxone,no antagonism to the analgesic effect of TAPN had been found by ip or icv Naloxone.Conclusion It may be the mainly peripheral analgesic mechanism that TAPN could lower the PGE_2 level in celiac fluid.Its central analgesic mechanisms are not related to opium receptors.