Tahara A, Saito M, Sugimoto T, Tomura Y, Wada K, Kusayama T, Tsukada J, Ishii N, Yatsu T, Uchida W, Tanaka A
Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan.
Naunyn Schmiedebergs Arch Pharmacol. 1998 Jan;357(1):63-9. doi: 10.1007/pl00005139.
The effects of YM087 (4'-[(2-methyl-1,4,5,6-tetrahydroimidazo[4,5-d] [1]benzazepin-6-yl)-carbonyl]-2-phenylbenzanilide monohydrochloride), a novel nonpeptide vasopressin (AVP) receptor antagonist, on [3H]AVP binding to human AVP receptors (V1A, V1B and V2) cloned and transiently expressed in COS-1 cells generated from monkey renal tissue were studied. Scatchard analysis of saturation isotherms for the specific binding of [3H]AVP to membranes, prepared from COS-1 cells transfected with human V1A, V1B and V2 receptors, yielded an apparent equilibrium dissociation constant (Kd) of 0.67 nM, 0.28 nM and 2.14 nM and a maximum receptor density (Bmax) of 2180 fmol/mg protein, 369 fmol/mg protein and 2660 fmol/mg protein, respectively. YM087 showed high affinity for AVP V1A and V2 receptors with Ki values of 6.3 and 1.1 nM, respectively, but had no effect on [3H]AVP binding to AVP V1B receptors. In COS-1 cells expressing either AVP V1A or V1B receptors, AVP caused a concentration-dependent increase in intracellular Ca2+ concentration ([Ca2+]i). YM087 inhibited the AVP-induced increase in [Ca2+]i in COS-1 cells expressing AVP V1A receptors in a concentration-dependent manner with an IC50 value of 14.3 nM, but did not influence this increase in AVP V1B-receptor expressing cells. In contrast, stimulation of COS-1 cells expressing AVP V2 receptors resulted in an accumulation of cAMP. YM087 inhibited AVP-induced cAMP production in COS-1 cells expressing AVP V2 receptors in a concentration-dependent manner with an IC50 value of 1.95 nM. In all assays used, YM087 was devoid of any agonistic activity. These results suggest that YM087 is a potent nonpeptide dual human AVP V1A and V2 receptor antagonist, and that YM087 will be a powerful tool in investigation of the physiological and pathophysiological roles of AVP.
研究了新型非肽类血管加压素（AVP）受体拮抗剂YM087（4'-[(2-甲基-1,4,5,6-四氢咪唑并[4,5-d][1]苯并氮杂卓-6-基)-羰基]-2-苯基苯甲酰胺盐酸盐）对[3H]AVP与在源自猴肾组织的COS-1细胞中克隆并瞬时表达的人AVP受体（V1A、V1B和V2）结合的影响。对用人类V1A、V1B和V2受体转染的COS-1细胞制备的膜上[3H]AVP特异性结合的饱和等温线进行Scatchard分析，得到的表观平衡解离常数（Kd）分别为0.67 nM、0.28 nM和2.14 nM，最大受体密度（Bmax）分别为2180 fmol/mg蛋白、369 fmol/mg蛋白和2660 fmol/mg蛋白。YM087对AVP V1A和V2受体具有高亲和力，Ki值分别为6.3和1.1 nM，但对[3H]AVP与AVP V1B受体的结合没有影响。在表达AVP V1A或V1B受体的COS-1细胞中，AVP引起细胞内Ca2+浓度（[Ca2+]i）呈浓度依赖性增加。YM087以浓度依赖性方式抑制表达AVP V1A受体的COS-1细胞中AVP诱导的[Ca2+]i增加，IC50值为14.3 nM，但不影响表达AVP V1B受体的细胞中[Ca2+]i的增加。相反，刺激表达AVP V2受体的COS-1细胞导致cAMP积累。YM087以浓度依赖性方式抑制表达AVP V2受体的COS-1细胞中AVP诱导的cAMP产生，IC50值为1.95 nM。在所有使用的测定中，YM087没有任何激动活性。这些结果表明YM087是一种有效的非肽类双重人AVP V1A和V2受体拮抗剂，并且YM087将成为研究AVP生理和病理生理作用的有力工具。
