大鼠和鸡大脑半球中的多个[35S]叔丁基双环硫代磷酸酯结合位点。

Multiple [35S]t-butylbicyclophosphorothionate binding sites in rat and chicken cerebral hemispheres.

作者信息

Tehrani M H, Clancey C J, Barnes E M

出版信息

J Neurochem. 1985 Oct;45(4):1311-4. doi: 10.1111/j.1471-4159.1985.tb05560.x.

DOI:10.1111/j.1471-4159.1985.tb05560.x

Abstract

Specific binding of [35S]t-butylbicyclophosphorothionate (TBPS) to membranes from cerebral hemispheres of adult rat and chicken was determined over a range of radioligand concentrations from 0.25 to 500 nM. Scatchard plots of these data were curvilinear and nonlinear regression analysis indicated binding to two sites that differ in affinity. For rat cerebrum, KD(1) = 1.15 nM, Bmax(1) = 0.085 pmol/mg; KD(2) = 232 nM, Bmax(2) = 16.9 pmol/mg. For chicken cerebrum, KD(1) = 1.39 nM, Bmax(1) = 0.111 pmol/mg; KD(2) = 166 nM, Bmax(2) = 17.6 pmol/mg. This multiplicity of [35S]TBPS binding was further confirmed when unlabeled TBPS or picrotoxinin displaced radioligand. The displacement curves were biphasic and yielded Hill coefficients from 0.65 to 0.70. These displacement curves were also resolved into two components with distinct IC50 values for unlabeled TBPS (rat, 1.55 and 271 nM; chicken, 2.40 and 224 nM). The IC50 values were similar to the dissociation constants obtained from equilibrium binding measurements.

摘要

在0.25至500 nM的一系列放射性配体浓度范围内，测定了[35S]叔丁基双环磷硫代酸盐（TBPS）与成年大鼠和鸡大脑半球膜的特异性结合。这些数据的Scatchard图呈曲线状，非线性回归分析表明其与两个亲和力不同的位点结合。对于大鼠大脑，KD(1) = 1.15 nM，Bmax(1) = 0.085 pmol/mg；KD(2) = 232 nM，Bmax(2) = 16.9 pmol/mg。对于鸡大脑，KD(1) = 1.39 nM，Bmax(1) = 0.111 pmol/mg；KD(2) = 166 nM，Bmax(2) = 17.6 pmol/mg。当未标记的TBPS或印防己毒素取代放射性配体时，[35S]TBPS结合的这种多重性得到了进一步证实。置换曲线是双相的，希尔系数为0.65至0.70。这些置换曲线也被解析为两个成分，未标记的TBPS具有不同的IC50值（大鼠，1.55和271 nM；鸡，2.40和224 nM）。IC50值与从平衡结合测量中获得的解离常数相似。