左旋咪唑与咪唑啉2受体的放射性受体配基实验观察

Observation of Levamisole on Imidazoline I_2 Receptors Binding Assay in Brain of Rats

目的:观察左旋咪唑(LMS)在体外实验中能否与正常大鼠脑组织咪唑啉2受体(I_2R)结合;LMS在体内长期处理能否引起大鼠脑内I_2R的变化。方法:通过正常大鼠脑组织I_2R与放射性配基的竞争结合实验,测定其平衡解离常数(K_i)及50%的放射性配基结合被取代所需的竞争剂浓度(IC_(50)),观察LMS与I_2R在体外的结合能力。通过LMS长期体内处理大鼠脑组织I_2R饱和结合实验,测定LMS长期处理大鼠和对照组大鼠脑组织I_2R密度和亲和力的变化。结果:体外实验发现,LMS能与[~3H]-2BFI竞争结合大鼠脑组织的I_2R,且具有浓度依赖性。IC_(50)值为1.292×10^(-5)mol·L^(-1),K_i值为9.796×10^(-6)mol·L^(-1)。大鼠体内长期LMS处理,其脑组织I_2R密度明显上调(P<0.05),而亲和力两组相比差异无统计学意义。结论:左旋咪唑在体外能与脑组织I_2R直接结合,可能是I_2R的配基。左旋咪唑长期作用于体内能引起脑组织I_2R密度的上调。

Objective：To investigate whether LMS could bind to I_2 R in vitro and the changes of I_2 R sites in brain of chronic treatments rats.Method;Ki and IC_（50） were measured by using competition binding studies.The changes of I_2R sites in brain of chronic treatments rats were observed by using saturation binding studies.Result：Levamisole inhibited the binding of[~3 H]2-BFI to I_2R and the inhibition is concentration dependent.The IC_（50） was 1.292×10^（-5）mol· L^（-1） and the K_i was 9.796×10^（-6） mol？ L^（-1）;The receptor＇ s density of I_2 R significandy up-regulated in LMS group.（n=6,P0.05）.No significant difference was observed in affinity.Conclusion： Levamisole can bind to imidazoline I_2R in vitro.Chronic treatment with LMS up-regulated I_2R-bingding sites in rat brain.