De Blas A L, Park D, Friedrich P
Brain Res. 1987 Jun 16;413(2):275-84. doi: 10.1016/0006-8993(87)91018-3.
The anti-benzodiazepine monoclonal antibody 21-7F9 has been used for the identification and study of endogenous benzodiazepine-like molecules in the human, rat and bovine brains. A sandwich radioimmunoassay has been designed for the quantification of the membrane-bound endogenous benzodiazepine-like molecules. The localization of these molecules is not restricted to the brain tissue. They are also present in kidney, liver and spleen as well as in the neuroblastoma X glioma NG108-15 hybrid cell line. Immunoblots show benzodiazepine-like immunoreactivity in the membrane proteins of all of these tissues. The membrane-bound benzodiazepine-like molecules are resistant to limited proteolysis of the membranes. Moreover, this treatment increases the binding of the monoclonal antibody 21-7F9 to the membranes, probably by exposing sites that normally are not accessible to the antibody. Immunocytochemistry experiments show that benzodiazepine-like molecules are also present in samples of human cerebella that have been stored in paraffin since 1940, 15 years before the first chemical synthesis of benzodiazepines. The results indicate that the cerebellar benzodiazepine-like molecules recognized by the antibody are the product of biological (not chemical) synthesis. Benzodiazepine-like immunoreactivity has also been detected in NG108-15 cells that have been cultured for 3 months in serum-free medium. These results suggest that the cells could biosynthesize benzodiazepine-like molecules.
抗苯二氮䓬单克隆抗体21-7F9已被用于鉴定和研究人、大鼠和牛脑中内源性苯二氮䓬样分子。已设计出一种夹心放射免疫分析法来定量膜结合的内源性苯二氮䓬样分子。这些分子的定位并不局限于脑组织。它们也存在于肾脏、肝脏和脾脏以及神经母细胞瘤X胶质瘤NG108-15杂交细胞系中。免疫印迹显示所有这些组织的膜蛋白中都有苯二氮䓬样免疫反应性。膜结合的苯二氮䓬样分子对膜的有限蛋白酶解具有抗性。此外，这种处理增加了单克隆抗体21-7F9与膜的结合，可能是通过暴露抗体通常无法接近的位点。免疫细胞化学实验表明，自1940年（即苯二氮䓬首次化学合成前15年）以来保存在石蜡中的人小脑样本中也存在苯二氮䓬样分子。结果表明，抗体识别的小脑苯二氮䓬样分子是生物（而非化学）合成的产物。在无血清培养基中培养3个月的NG108-15细胞中也检测到了苯二氮䓬样免疫反应性。这些结果表明，细胞可以生物合成苯二氮䓬样分子。
