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目的 开展N-乙酰胆碱受体(N-AChR)的动力学研究.方法 (1)选择a-BuTX作为主要工具药,进行~(125)I-a-BuTX与电鳐电器官的N-AChR饱和结合实验,用Scatfit程序拟合。125I-a-BuTX与电鳐电器官的N-AChR结合的解离动力学实验,当结合达到饱合后,向两个反应体系分别加入1000倍以上的a-BuTX或烟碱.不同时间取样、分离后,γ-计数仪计数。(2) 13日龄的鸡胚骨骼肌N-AChR及20日龄的鸡视叶的N-AChR与~(125)-I-a-BuTX饱和结合实验,用Scaifit程序拟合。另外以烟碱对125I-a-BuTX与电鳐电器官、鸡视叶、鸡胚骨骼肌N-AChR结合的竞争实验,用Logit程序计算IC_(50)值。结果(1)1251-a-BuTX与电鳐电器官的N-AChR饱和结合实验得到一条双曲线的Scatchard图,符合一配基两受体结合模型,求得高、低两个结合位点和两个B_(max)(最大结合值),两个体系的解离动力学均为二次解离曲线,分别求得两个解离常数和两个半衰期.(2)两种实验结果,均符合一配基一受体结合模型,分别求得一个结合位点和一个B_(max).烟碱对~(125)-I-a-BuTX电鳐电器官的N-AChR结合的竞争作用IG_(50)值分别为3.86×10~(-5)和1.65×10~(-6)mol.对鸡视叶的N-AChR竞争作用.IC_(50)值为6.02×10~(-7)mol,对骨骼肌竞争作用IG_(50)值为4.60×10~(-6)。结论 (1)电鳐电器官中存在~(12
Objective To investigate the kinetics of N-acetylcholine receptor (N-AChR) .Methods (1) A-BuTX was chosen as the main tool to conduct the saturation binding experiment of 125 Ia-BuTX with N-AChR , Fitted with the Scatfit program. Dissociation kinetics of 125I-a-BuTX binding to N-AChR in electrical organs. When the binding reached saturation, 1000-fold more a-BuTX or nicotine was added to the two reaction systems, respectively. After separation, γ-counter counts. (2) Saturation binding assay of N-AChR and ~ (125) -I-a-BuTX in chicken embryo skeletal muscle N-AChR at 13 days old and 20-day-old chicken visual leaf were fitted by Scaifit program. In addition, nicotine 125I-a-BuTX and electric organ, chicken chicken leaf, chick skeletal muscle N-AChR competition experiments, using Logit program to calculate IC 50 values. Results (1) A hyperbolic Scatchard plot of 1251-a-BuTX binding to N-AChR in electrical organs was obtained and fitted with a ligand-receptor binding model to obtain high and low binding sites and The two B max (maximum binding values) and the dissociation kinetics of the two systems are quadratic dissociation curves, and two dissociation constants and two half-lives are obtained respectively. (2) Both experimental results The binding activity of nicotine to N-AChR in ~ (125) -Ia-BuTX electrical organs was determined by fitting a ligand-receptor binding model with a binding site and a B max ) Were 3.86 × 10 ~ (-5) and 1.65 × 10 ~ (-6) mol, respectively.The competition of N-AChR in chicken leaf was observed.The value of IC 50 was 6.02 × 10 -7 mol / The value of IG 50 in skeletal muscle competition was 4.60 × 10 -6. Conclusions (1) There are ~ (12