豚鼠肺膜LTD4受体结合特征及二苯乙烯低聚体(Gn-3)的LTD4受体拮抗作用

 目的 采用LTD₄放射受体结合实验方法,在分析LTD₄受体的有关特征的基础上,观察比较二苯乙烯低聚体(Gn-3)对LTD₄受体的拮抗作用。方法 以豚鼠肺膜为实验材料,采用³H-LTD₄为放射配体,以FPL₅₅₇₁₂作阳性对照药物,Gn-3为实验药物,进行药物竞争结合实验。采用离体器官生物检测法鉴定Gn-3对LTD₄受体的拮抗作用。结果³H-LTD₄与其相应受体呈现单一结合位点,其Kd和B_max值分别为19.9×10^-11mol·L^-1和232.9 fmol·mg^-1蛋白。Gn-3可明显取代³H-LTD₄与其受体结合,IC₅₀值为5.71×10^-7 mol·L^-1,Ki值为2.54×10^-7 mol·L^-1。生物学鉴定法证实Gn-3可抑制LTD-4引起的生物学效应。结论 豚鼠肺膜LTD₄受体为单一结合位点受体,Gn-3为高活性的LTD4受体拮抗剂。

Studies on the characteristics of LTD4receptor with radio-ligand binding assay and the effect of Gn-3

OBJECTIVE To study the effect of Gn-3 on the LTD₄receptor by using a radio-ligand binding assay of LTD₄. METHODS Lung membrane of guinea pig was used as experimental materials,3H-LTD was used as radio ligand,FPL₅₅₇₁₂was chosen as the positive control drug,Gn-3 was used as the tested drug and bioassay in vitro was used to determine the biological function of Gn-3. RESULTS The binding of 3H-LTD 4 to its receptor was specific,saturable and reversible.The Kd and B_maxvalues were 19.9×10^-11mol·L^-1and 232.9 fmol·mg^-1 protein respectively at 30℃.Gn-3 inhibited 3H-LTD₄in competing against LTD₄receptor.The IC₅₀and Ki value were 5.71×10^-7mol·L^-1and 2.54×10^-7mol·L^-1respectively.It was also determined that Gn-3 was LTD4 receptor antagonist by the bioassay in vitro. CONCLUSION The binding of 3H-LTD₄on guinea pig lung membrane showed a single binding site.Gn-3 appeared to be an effective LTD₄ receptor antagonist.