Zhang W, Zhi J, Guo W, Zhao R, Jin G
Department of Physiology, Shanxi Medical University, Taiyuan 030001.
Yao Xue Xue Bao. 1998 Oct;33(10):721-6.
The effects of l-stepholidine(l-SPD) on peripheral vascular dopamine DA1 and DA2 receptors were studied using isolated vascular rings in rabbits. It was shown that (1) l-SPD(0.1-10 mumol.L-1) shifted the dose-response curves to the right in a nonparallel fashion and decreased the maximal response (Emax) of both the fenoldopam(FODA, a selective DA1 agonist)-induced and the propyl-buty-dopamine(PBDA, a selective DA2 agonist)-induced vasorelaxation showing a non-competitive antagonistic action. The pD2 values of l-SPD for FODA in the renal, pulmonary and mesenteric arteries were 5.43, 5.48 and 5.58, respectively. The pD2 values for PBDA in the mesenteric and femoral arteries were 5.35 and 5.89, respectively. The potencies of its antagonistic action were comparable to SCH23390, a selective DA1 antagonist, and to domperidone, a selective DA2 antagonist. (2) l-SPD(0.1-100 mumol.L-1) per se was also found to induce slight but dose-related vasorelaxations in the renal and pulmonary arteries displaying its DA1 agonistic activity. Its pD2 values were 4.98 and 5.02, respectively. However, its Emax were considerably smaller than that of FODA. These results suggest that l-SPD is a mixed peripheral DA1 and DA2 receptor antagonists and weak DA1 receptor agonist with pharmacological property of dual action.
采用兔离体血管环研究左旋千金藤啶碱（l-SPD）对外周血管多巴胺DA1和DA2受体的作用。结果表明：（1）l-SPD（0.1～10 μmol·L-1）使剂量-反应曲线呈非平行右移，降低了非诺多泮（FODA，一种选择性DA1激动剂）诱导的和丙基丁基多巴胺（PBDA，一种选择性DA2激动剂）诱导的血管舒张的最大反应（Emax），表现为非竞争性拮抗作用。l-SPD对肾动脉、肺动脉和肠系膜动脉中FODA的pD2值分别为5.43、5.48和5.58。l-SPD对肠系膜动脉和股动脉中PBDA的pD2值分别为5.35和5.89。其拮抗作用的强度与选择性DA1拮抗剂SCH23390和选择性DA2拮抗剂多潘立酮相当。（2）还发现l-SPD（0.1～100 μmol·L-1）本身可在肾动脉和肺动脉中诱导轻微但与剂量相关的血管舒张，显示其DA1激动活性。其pD2值分别为4.98和5.02。然而，其Emax明显小于FODA的Emax。这些结果表明，l-SPD是一种外周DA1和DA2受体混合型拮抗剂及弱DA1受体激动剂，具有双重药理作用特性。
