Résumé
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.