Clark B J, Menninger K
Circ Res. 1980 Jun;46(6 Pt 2):I59-63.
Dopamine produces dilation predominantly in renal and mesenteric vascular beds. An action on a specific receptor has been confirmed in vitro using a perfused canine mesenteric vessel preparation. Reductions in resistance produced by dopamine are selectively inhibited by methylergometrine (pA2 = 8.3) and sulpiride (pA2 = 5.6). Evidence is accumulating which suggests that vascular dopamine receptors are innervated. Periaterial nerve stimulation in anesthetized dogs produces increases in blood flow in the superior mesenteric artery which are not influenced by atropine and propranolol but are inhibited by haloperidol. Dopamine receptors are also present at sympathetic ganglia and sympathetic nerve terminals. Inhibition of noradrenaline release resulting from stimulation of these receptors may make an important contribution to the depressor effects of dopamine receptor agonists in anesthetized animals and in man. Reductions in blood pressure induced by bromocriptine and other long-acting dopamine receptor stimulants are frequently associated with reductions in heart rate, but not always with a corresponding depression of myocardial contractile force. This phenomenon may be explained by a selective distribution of prejunctional receptors in sympathetic neurons innervating the sinus node.
多巴胺主要使肾和肠系膜血管床扩张。使用灌注犬肠系膜血管制备物在体外已证实其对特定受体有作用。多巴胺产生的阻力降低被甲基麦角新碱（pA2 = 8.3）和舒必利（pA2 = 5.6）选择性抑制。越来越多的证据表明血管多巴胺受体受神经支配。麻醉犬的动脉周围神经刺激可使肠系膜上动脉血流增加，这不受阿托品和普萘洛尔影响，但受氟哌啶醇抑制。多巴胺受体也存在于交感神经节和交感神经末梢。刺激这些受体导致去甲肾上腺素释放受抑制，这可能对多巴胺受体激动剂在麻醉动物和人体中的降压作用起重要作用。溴隐亭和其他长效多巴胺受体激动剂引起的血压降低常伴有心率降低，但并非总是伴有相应的心肌收缩力抑制。这种现象可能是由于支配窦房结的交感神经元中节前受体的选择性分布所致。
