Zweig A, Siegel M I, Egan R W, Clark M A, Shorr R G, West R E
Department of Allergy and Immunology, Schering-Plough Research Institute, Bloomfield, New Jersey 07003.
J Neurochem. 1992 Nov;59(5):1661-6. doi: 10.1111/j.1471-4159.1992.tb10996.x.
The H3 receptor is a high-affinity histamine receptor that inhibits release of several neurotransmitters, including histamine. We have characterized H3 receptor binding in bovine brain and developed conditions for its solubilization. Particulate [3H]histamine binding showed an apparently single class of sites (KD = 4.6 nM; Bmax = 78 fmol/mg of protein). Of the detergents tested, digitonin at a detergent/protein ratio of 1:1 (wt/wt) yielded the greatest amount of solubilized receptors, typically 15-30% of particulate binding. Neither equilibrium binding of [3H]histamine to receptors (KD = 6.1 nM; Bmax = 92 fmol/mg of protein) nor the inhibitor profile was substantially altered by digitonin solubilization. However, solubilization did increase the rate of [3H]histamine association with and dissociation from the receptor. Size-exclusion chromatography indicated an apparent molecular weight of 220,000 for the solubilized receptor, and peak binding from this column retained its guanine nucleotide sensitivity. These last two observations are consistent with the solubilized receptor occurring in complex with a guanine nucleotide-binding protein.
H3受体是一种高亲和力的组胺受体，可抑制包括组胺在内的多种神经递质的释放。我们已对牛脑中的H3受体结合进行了表征，并开发了其增溶条件。微粒体[3H]组胺结合显示出明显单一的位点类别（解离常数KD = 4.6 nM；最大结合量Bmax = 78 fmol/mg蛋白质）。在所测试的去污剂中，去污剂与蛋白质比例为1:1（重量/重量）的洋地黄皂苷产生的增溶受体量最大，通常为微粒体结合量的15%至30%。洋地黄皂苷增溶对[3H]组胺与受体的平衡结合（KD = 6.1 nM；Bmax = 92 fmol/mg蛋白质）和抑制剂谱均无实质性改变。然而，增溶确实增加了[3H]组胺与受体结合和解离的速率。尺寸排阻色谱法表明增溶受体的表观分子量为220,000，该柱的峰值结合保留了其对鸟嘌呤核苷酸的敏感性。最后这两个观察结果与增溶受体与鸟嘌呤核苷酸结合蛋白形成复合物的情况一致。
