四氢小檗碱对外周血管多巴胺DA_1和DA_2受体亚型的作用

Effects of Tetrahydroberberine on Peripheral Vascular Dopamine DA_1 and DA_2 Receptor Subtypes

目的 :研究四氢小檗碱 (THB)对外周血管DA1和DA2 受体亚型的作用。方法 :采用家兔离体血管环方法。结果 :THB使DA1受体激动剂FODA诱发的肾、肺和肠动脉以及DA2 受体激动剂PBDA诱发的肠和股动脉舒张反应的量效曲线非平行右移 ,最大反应 (Emax)降低 ,均呈非竞争性拮抗。结论 :THB为外周血管DA1和DA2 受体的混合性阻滞剂作用特性 ,其作用与左旋千金藤定碱 (l SPD)相似 ,但弱于l SPD。

Objective:To study the effect of tetrahydroberberine(THB) on the peripheral vascular dopamine DA 1 and DA 2 receeptors.Method:Using isolated vascular rings method.Result:THB(0.1～10 μmol·L -1 )shifted the dose response curves to the right in a nonparallel fashion and decreased the maximal response(E max )of both the fenoldopam(FODA,a selective DA 1 agonist) induced and the propyl butyl dopamine(PBDA,a selective DA 2 agonist) induced vasorelaxation, showing a non competitive antagonistic action.The pD'2 values of THB for FODA in the renal,pulmonary and mesenteric arteries were 5.29,5.37 and 5.46,respectively, while for PBDA in the mesenteric and femoral arteries were 5.53 and 5.48,respectively.The potencies of this antagonistic action were weaker than those of SCH23390,a selective DA 1 antagonist,domperidone,a selective DA 2 antagonist and l SPD,a mixed DA 1/DA 2 antagonist, domperidone, a selective DA 2 antagonist and l SPD, a mixed DA 1/DA 2 antagonist.Conclusion:THB is a mixed peripheral DA, and DA 2 receptor antagonist similar to l SPD.