Asano T, Yamada Y, Ogasawara N
J Neurochem. 1983 Jan;40(1):209-14. doi: 10.1111/j.1471-4159.1983.tb12672.x.
GABA and benzodiazepine receptors were solubilized from bovine cerebral cortex, cerebellum, and hippocampus and then partially purified by gel filtration and characterized. The apparent molecular weights of all these receptors were determined to be 600,000-650,000 by gel filtration, the sedimentation coefficients being 11.0-11.3 S by sucrose density gradient centrifugation. [3H]Muscimol was bound to two classes of sites in fractions from all three regions, and [3H]flunitrazepam bound to one class of sites. A comparison of the ratios of Bmax for flunitrazepam binding to Bmax for muscimol binding revealed that the fractions from the hippocampus exhibited a much higher ratio of benzodiazepine binding sites than were detected in fractions from the cortex and cerebellum. GABA agonist and antagonist inhibited [3H]muscimol binding to the fractions from these regions, at similar concentrations. Benzodiazepine agonists and antagonists also inhibited [3H]flunitrazepam binding in these three fractions, with similar potency. CL 218,872, however, inhibited [3H]flunitrazepam binding in the cerebellar fraction with the lowest IC50 value and that in th hippocampal fraction with the highest IC50 value. Hill coefficients for CL 218,872 inhibition were 0.98, 0.64, and 0.58 for cerebellum, cortex, and hippocampus, respectively.
从牛大脑皮层、小脑和海马体中提取γ-氨基丁酸（GABA）和苯二氮䓬受体，然后通过凝胶过滤进行部分纯化并加以表征。通过凝胶过滤测定所有这些受体的表观分子量为600,000 - 650,000，通过蔗糖密度梯度离心法测定沉降系数为11.0 - 11.3 S。[³H]蝇蕈醇与来自所有三个区域的组分中的两类位点结合，[³H]氟硝西泮与一类位点结合。比较氟硝西泮结合的最大结合量（Bmax）与蝇蕈醇结合的Bmax的比值发现，海马体的组分中苯二氮䓬结合位点的比例远高于在皮层和小脑的组分中检测到的比例。GABA激动剂和拮抗剂在相似浓度下抑制[³H]蝇蕈醇与这些区域的组分结合。苯二氮䓬激动剂和拮抗剂也以相似的效力抑制这三个组分中的[³H]氟硝西泮结合。然而，CL 218,872以最低的半数抑制浓度（IC50）值抑制小脑组分中的[³H]氟硝西泮结合，以最高的IC50值抑制海马体组分中的[³H]氟硝西泮结合。CL 218,872抑制的希尔系数在小脑、皮层和海马体中分别为0.98、0.64和0.58。
