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实验观察了选择性多巴胺 (DA)DA1受体激动剂fenoldopam与DA2 受体激动剂propy1 butyl dopamine (PB DA)对兔肾动脉 ,肺、肠系膜动脉和股动脉环磷酸腺苷 (cAMP)产生系统的影响。结果表明 :(1)除股动脉外 ,fenoldopam均可浓度依赖性地增加肺动脉、肾动脉和肠系膜动脉cAMP的生成量。选择性DA1受体阻断剂SCH2 3390可以显著阻断fenoldopam的效应 ,而DA2 受体阻断剂domperidone则对fenoldopam的这一效应不产生任何影响。 (2 )PBDA可浓度依赖性地降低股动脉的cAMP生成量 ,又可浓度依赖性地激活肠系膜动脉、肺动脉和肾动脉的腺苷酸环化酶 (AC)活性 ,增加cAMP的生成量。 (3)domperidone可明显减小PBDA对股动脉AC活性的抑制效应 ,并可使PBDA对肠系膜动脉AC活性效应增强 ,但不改变PBDA对肾动脉和肺动脉的AC活性效应。 (4)SCH2 3390不影响PBDA对股动脉AC活性的抑制效应 ,可显著降低PBDA对肾动脉、肺动脉和肠系膜动脉激活AC活性的效应 ,cAMP的含量显著减小。以上结果提示 ,在肺动脉、肾动脉和肠系膜动脉上存在DA1受体介导的cAMP产生系统 ,而在股动脉仅有DA2 受体介导的cAMP产生系统。在肠系膜动脉既存在DA2 受体介导的cAMP产生系统 ,又存在DA1受体介导的cAMP产生系统。PBDA既有通过刺激DA2 受体抑制AC活性的作用 ,又?
The effects of selective dopamine DA1 receptor agonist fenoldopam and DA2 receptor agonist propy1 butyl dopamine (PB DA) on the production of cAMP in rabbit renal, pulmonary, mesenteric and femoral arteries were systematically investigated influences. The results showed that: (1) except the femoral artery, fenoldopam could increase the cAMP production in pulmonary artery, renal artery and mesenteric artery in a concentration-dependent manner. The selective DA1 receptor blocker SCH2 3390 significantly blocked the effect of fenoldopam, whereas the DA2 receptor blocker domperidone did not have any effect on this effect of fenoldopam. PBDA can decrease cAMP production in femoral artery in a concentration-dependent manner, and also activate adenylyl cyclase (AC) activity of mesenteric artery, pulmonary artery and renal artery in a concentration-dependent manner and increase cAMP production. (3) Domperidone can significantly reduce the inhibitory effect of PBDA on the AC activity of the femoral artery, and can make the effect of PBDA on the AC activity of the mesenteric artery enhanced, but does not change the AC activity effect of PBDA on the renal arteries and pulmonary arteries. (4) SCH2 3390 did not affect the inhibitory effect of PBDA on the AC activity of the femoral artery, and could significantly reduce the effect of PBDA on the activation of AC in renal artery, pulmonary artery and mesenteric artery, and the content of cAMP was significantly reduced. These results suggest that there is a DA1 receptor-mediated cAMP production system in the pulmonary arteries, renal arteries and mesenteric arteries whereas only the DA2 receptor-mediated cAMP production system in the femoral artery. In the mesenteric artery, there are both the DA2 receptor-mediated cAMP production system and the DA1 receptor-mediated cAMP production system. PBDA both through the stimulation of DA2 receptor inhibition of AC activity, and?