Ikezono K, Zerkowski H R, Beckeringh J J, Michel M C, Brodde O E
J Pharmacol Exp Ther. 1987 Apr;241(1):294-9.
On isolated strips of human saphenous vein, pretreated with 5 microM phenoxybenzamine and contracted with 10 mM KCl, the beta adrenoceptor mediating the relaxant effects of isoproterenol, procaterol and norepinephrine was characterized using the selective beta-1 adrenoceptor antagonist, bisoprolol, and the selective beta-2 adrenoceptor antagonist, ICI 118,551. All three agonists produced concentration-dependent relaxations of the isolated saphenous vein with an order of potency: procaterol (pD2 value, 7.69) greater than isoproterenol (pD2 value, 7.41) much greater than norepinephrine (pD2 value, 5.30). ICI 118,551 (3 X 10(-10) to 3 X 10(-9) M) was nearly 100 times more potent than bisoprolol (10(-7) to 10(-6) M) in antagonizing the relaxant effects of isoproterenol and procaterol. The slopes of the Schild plots for the antagonistic effects of ICI 118,551 and bisoprolol against isoproterenol- and procaterol-induced relaxations were not significantly different from unity indicating interaction with a homogeneous population of beta adrenoceptors. The pA2 value for ICI 118,551 amounted to 9.11 to 9.20 and for bisoprolol to 6.50 to 6.63. In addition, the concentration-response curve for the relaxant effect of norepinephrine was significantly shifted to the right by 10(-9) M ICI 118,551, but not affected by 10(-7) M bisoprolol. These results indicate that on the isolated strips of the human saphenous vein the beta adrenoceptor mediating relaxation is of the beta-2 subtype.
在用人隐静脉分离条带进行的实验中，先使用5微摩尔酚苄明预处理，再用10毫摩尔氯化钾使其收缩，然后使用选择性β-1肾上腺素能受体拮抗剂比索洛尔和选择性β-2肾上腺素能受体拮抗剂ICI 118,551来鉴定介导异丙肾上腺素、丙卡特罗和去甲肾上腺素舒张作用的β肾上腺素能受体。所有这三种激动剂均使分离的隐静脉产生浓度依赖性舒张，其效价顺序为：丙卡特罗（pD2值，7.69）大于异丙肾上腺素（pD2值，7.41）远大于去甲肾上腺素（pD2值，5.30）。在拮抗异丙肾上腺素和丙卡特罗的舒张作用方面，ICI 118,551（3×10⁻¹⁰至3×10⁻⁹摩尔/升）的效力比索洛尔（10⁻⁷至10⁻⁶摩尔/升）强近100倍。ICI 118,551和比索洛尔对异丙肾上腺素和丙卡特罗诱导的舒张作用的拮抗作用的Schild图斜率与1无显著差异，表明与β肾上腺素能受体的同质群体相互作用。ICI 118,551的pA2值为9.11至9.20，比索洛尔的pA2值为6.50至6.63。此外，去甲肾上腺素舒张作用的浓度-反应曲线被10⁻⁹摩尔/升的ICI 118,551显著右移，但不受10⁻⁷摩尔/升比索洛尔的影响。这些结果表明，在人隐静脉分离条带上介导舒张的β肾上腺素能受体是β-2亚型。
