非诺多泮对兔肺动脉和肠动脉cAMP产生系统影响的研究

目的 :对比分析多巴胺 1受体激动剂非诺多泮对兔肺动脉和肠系膜动脉的影响。方法 :采用cAMP含量放射免疫测定法测定DA1受体激动剂非诺多泮对肾动脉和肠系膜动脉cAMP的影响。结果 :非诺多泮可剂量依赖性增加肠、肺动脉cAMP的生成量 ,然而 ,肠动脉cAMP的生成量显著高于肺动脉cAMP的生成量。选择性多巴胺(DA1)受体阻断剂SCH2 3 3 90能够阻断非诺多泮所引起的肺动脉和肠动脉cAMP生成量增加 ,多巴胺 2 (DA2 )受体阻断剂Domperidone则不影响非诺多泮的作用。结论 :在兔肺和肠动脉均存在有刺激AC活性的DA1受体。但肺动脉DA1受体的位点数明显少于肠动脉DA1受体位点数 ,从而提示肺动脉DA1受体的生理作用弱于肠动脉。

Comparison of the effects of fenoldopam on the cAMP generating system in rabbit mesenteric and pulmonary arteries

Objective: To evaluate and compare the effects of DA1 receptor agonist,fenoldopam,rabbit pulmonary and mesen-teric arteries. Methods: Using radioimmunoassay determined effects of fenoldopam on the cAMP generating system in rabbitmeaenteric and pulmonary arteries. Results: The selective DA1-receptors agonist, fenoldopam, induced a dose-related increasescAMP formation in mesenteric and pulmonary arteries; however, them agnitude of increase in the mesenteric artery was re-markably greater than that in the pulmonary artery. The selective DA1-receptors antagonist,SCH23390,blocked fenoldopam-in-duced cAMP production, while the selective DA2-receptors antagonist, domperidone, was without effect on the increase of cAMPelicited by fenoldopam. Conclusion: The presence of DA1-receptors associated with stimulation of AC activity in both mesen-teric and pulmonary arteries. However, there are much fewer receptor sites in the pulmonary artery than in mesenteric artery,suggesting less physioloieal importace of such recePtors in the pulmonary artery than in the mesenteric artery.