Goldberg M R, Kadowitz P J
Circ Res. 1978 Sep;43(3):357-64. doi: 10.1161/01.res.43.3.357.
We studied and compared the effects of 5- and 6-hydroxydopamine (5- or 6-OHDA) on venous tone and on adrenergic and nonadrenergic responses of the isolated canine saphenous vein. In the tissue bath, both 5- and 6-OHDA caused increases in tone and abolished adrenergic responses to transmural nerve stimulation. Effects of 6-OHDA were blocked by desmethylimipramine. 6-OHDA reduced norepinephrine levels of venous strips to 15% of those in control strips. Neither 5- nor 6-OHDA markedly altered peak contractile responses to norepinephrine but 6-OHDA prolonged the response to norepinephrine. Both compounds reduced responses to tyramine, with 6-OHDA producing a greater reduction than 5-OHDA. Large contractile responses to 5-OHDA were blocked only partially by treatment of strips with 6-OHDA, suggesting that contractile responses to 5-OHDA were mediated by direct and indirect actions. These results suggest differences in the actions of 5- and 6-OHDA on adrenergic terminals and smooth muscle in saphenous veins. The results of the experiments suggest that both 5- and 6-OHDA may be useful pharmacological interventions for the study of adrenergic mechanisms in isolated blood vessels.
我们研究并比较了5-羟多巴胺（5-OHDA）和6-羟多巴胺（6-OHDA）对离体犬隐静脉静脉张力以及肾上腺素能和非肾上腺素能反应的影响。在组织浴中，5-OHDA和6-OHDA均引起张力增加，并消除了对跨壁神经刺激的肾上腺素能反应。6-OHDA的作用被去甲丙咪嗪阻断。6-OHDA将静脉条带中的去甲肾上腺素水平降至对照条带的15%。5-OHDA和6-OHDA均未显著改变对去甲肾上腺素的峰值收缩反应，但6-OHDA延长了对去甲肾上腺素的反应。两种化合物均降低了对酪胺的反应，6-OHDA的降低作用比5-OHDA更大。用6-OHDA处理条带仅部分阻断了对5-OHDA的大收缩反应，这表明对5-OHDA的收缩反应是由直接和间接作用介导的。这些结果表明5-OHDA和6-OHDA对隐静脉肾上腺素能终末和平滑肌的作用存在差异。实验结果表明，5-OHDA和6-OHDA可能都是用于研究离体血管肾上腺素能机制的有用药理学干预手段。
