目的：比较不同浓度三种阿片受体激动剂对突触传递的抑制作用．方法：用细胞内记录和细胞外微电泳技术，于大鼠伏核脑片制备上记录神经元的兴奋性突触后电位和谷氨酸钠所致细胞膜去极化．结果：（ＤＡｌａ２，ＮＭｅＰｈｅ４，Ｇｌｙｏｌ）ｅｎｋｅｐｈａｌｉｎ（ＤＡＧＯ），（ＤＰｅｎ２，５）ｅｎｋｅｐｈａｌｉｎ（ＤＰＥＮ），ａｎｄｔｒａｎｓ（±）３，４ｄｉｃｈｌｏｒｏＮｍｅｔｈｙｌＮ［２（１ｐｙｒｏｌｉｄｉｎｙｌ）ｃｙｃｌｏｈｅｘｙｌ］ｂｅｎｚｅｎｅａｃｅｔａｍｉｄｅｍｅｔｈａｎｅｓｕｌｆｏｎａｔｅ（Ｕ５０４８８Ｈ）（１μｍｏｌ·Ｌ－１）均降低突触传递，尤以ＤＡＧＯ抑制作用最著．结论：三种阿片受体激动剂对突触传递的抑制作用均具有浓度依赖性，其作用机制与谷氨酸介导的突触传递受抑制有关． OBJECTIVE: To compare the inhibitory effects of three opioid receptor agonists at different concentrations on synaptic transmission. Methods: The excitatory postsynaptic potential of neurons and the depolarization of cell membrane induced by sodium glutamate were recorded on the preparation of nucleus accumbens in rats by intracellular recording and extracellular micro-electrophoresis. Results: (DAla2, NMePhe4, Glyol) enkephalin (DPen2,5) enkephalin (DPEN), andtrans (±) 3,4dichloroN methylN  21pyrolidinyl cyclohexyl benzeneacetamidemethanesulonate (U50488H) (1μmol·L1) all reduced the synaptic transmission, especially in DAGO. CONCLUSION: All three opioid receptor agonists inhibit the synaptic transmission in a concentration-dependent manner, and its mechanism is related to the inhibition of glutamate-mediated synaptic transmission.