Koizumi T, Saita Y, Miyake A, Nishida A, Yazawa H, Honda K
Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Ibaraki, Japan.
Jpn J Pharmacol. 1996 Aug;71(4):307-13. doi: 10.1254/jjp.71.307.
We recently isolated a cDNA clone for the human cholecystokinin (CCK)B/gastrin receptor and permanently expressed this receptor cDNA in NIH-3T3 cells. [125I]CCK-8 specifically bound to the membrane of the transfectant, and this binding was displaced by unlabeled CCK-8 with an IC50 of 0.32 nM. Treatment of these cells with CCK-8 increased the intracellular Ca2+ concentration with an EC50 of 0.30 nM. Using these cells expressing functional human CCKB/gastrin receptors, we investigated the pharmacological properties of (R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1, 4-benzodiazepin-3-yl]-3-(3-methylphenyl) urea (YM022), a potent and selective CCKB/gastrin receptor antagonist in rats. YM022 potently inhibited [125I]CCK-8 binding to the membrane with an IC50 of 55 pM and CCK-8-induced Ca2+ mobilization with that of 7.4 nM. On the other hand, its racemate and enantiomer more weakly inhibited this binding (IC50 of 110 pM and 11 nM, respectively) and Ca2+ mobilization (IC50 of 18 nM and 94 nM, respectively). These results indicate that YM022 stereoselectively recognizes the human CCKB/gastrin receptor as a potent antagonist and that the established transfectant is useful for characterization of human CCKB/gastrin-receptor ligands.
我们最近分离出了人胆囊收缩素（CCK）B/胃泌素受体的cDNA克隆，并在NIH-3T3细胞中永久表达了该受体cDNA。[125I]CCK-8特异性结合转染细胞的膜，且这种结合可被未标记的CCK-8取代，其IC50为0.32 nM。用CCK-8处理这些细胞可使细胞内Ca2+浓度升高，其EC50为0.30 nM。利用这些表达功能性人CCK B/胃泌素受体的细胞，我们研究了（R）-1-[2,3-二氢-1-（2'-甲基苯甲酰）-2-氧代-5-苯基-1H-1,4-苯并二氮杂卓-3-基]-3-（3-甲基苯基）脲（YM022）的药理学特性，它是大鼠中一种强效且选择性的CCK B/胃泌素受体拮抗剂。YM022能有效抑制[125I]CCK-8与膜的结合，IC50为55 pM，同时抑制CCK-8诱导的Ca2+动员，IC50为7.4 nM。另一方面，其外消旋体和对映体对这种结合（分别为110 pM和11 nM的IC50）和Ca2+动员（分别为18 nM和94 nM的IC50）的抑制作用较弱。这些结果表明，YM022作为一种强效拮抗剂对人CCK B/胃泌素受体具有立体选择性识别，且所建立的转染细胞可用于鉴定人CCK B/胃泌素受体配体。
