De Mey J, Vanhoutte P M
Circ Res. 1981 Jun;48(6 Pt 1):875-84. doi: 10.1161/01.res.48.6.875.
We studied isolated canine arteries and veins to compare the pharmacological properties of their postjunctional alpha-adrenoceptors. Rings of femoral and splenic arteries and of femoral and saphenous veins were mounted for isometric tension recording in organ chambers filled with Krebs-Ringer bicarbonate solution. The four blood vessels contracted when exposed to methoxamine, norepinephrine, phenylephrine, and tramazoline; clonidine failed to induce contraction only in the splenic artery. The relative sensitivity to methoxamine was comparable in the arteries and veins, but that for phenylephrine was larger in the former. The veins, but not the arteries, were more sensitive to clonidine and tramazoline than to phenylephrine or methoxamine. Phentolamine was a competitive antagonist against norepinephrine in the arteries and the veins. Prazosin was a competitive antagonist arteries. The competitive antagonistic properties of yohimbine were more pronounced in the veins than in the arteries. Verapamil depressed to the same extent the contractile responses of saphenous veins to clonidine and norepinephrine, but reduced the contractions caused by methoxamine more than those due to norepinephrine. These results indicate the presence of both alpha 1- and alpha 2-like adrenoceptors on venous smooth muscle cells, whereas arterial smooth muscle cells contain mainly postjunctional alpha 1-adrenoceptors.
我们研究了分离的犬类动脉和静脉，以比较其节后α-肾上腺素能受体的药理学特性。将股动脉和脾动脉以及股静脉和大隐静脉的血管环安装在充满 Krebs-Ringer 碳酸氢盐溶液的器官浴槽中，用于等长张力记录。当暴露于甲氧明、去甲肾上腺素、苯肾上腺素和曲马唑啉时，这四种血管会收缩；可乐定仅在脾动脉中未能诱导收缩。动脉和静脉对甲氧明的相对敏感性相当，但对苯肾上腺素的敏感性在动脉中更大。静脉对可乐定和曲马唑啉比对苯肾上腺素或甲氧明更敏感，而动脉则不然。酚妥拉明在动脉和静脉中是去甲肾上腺素的竞争性拮抗剂。哌唑嗪是动脉的竞争性拮抗剂。育亨宾的竞争性拮抗特性在静脉中比在动脉中更明显。维拉帕米同等程度地抑制大隐静脉对可乐定和去甲肾上腺素的收缩反应，但对甲氧明引起的收缩的抑制作用比对去甲肾上腺素引起的收缩的抑制作用更大。这些结果表明静脉平滑肌细胞上同时存在α1-和α2-样肾上腺素能受体，而动脉平滑肌细胞主要含有节后α1-肾上腺素能受体。
