Miller V M, Vanhoutte P M
Am J Physiol. 1985 Apr;248(4 Pt 2):H432-7. doi: 10.1152/ajpheart.1985.248.4.H432.
Arachidonic acid produces endothelium-dependent relaxation in canine arteries and endothelium-dependent contraction in veins. In canine femoral arteries, the relaxation is prevented by inhibitors of cyclooxygenase. To determine the role of cyclooxygenase in the contraction evoked by arachidonic acid in the veins, rings of canine femoral and intrapulmonary veins, with and without endothelium, were suspended in organ chambers and set at their optimum length for isometric tension measurements. In rings of femoral and pulmonary vein contracted with norepinephrine, arachidonic acid produced a concentration-dependent increase in tension that was eliminated by removal of the endothelium or by treatment with the inhibitors of cyclooxygenase (indomethacin, meclofenamate, or acetylsalicyclic acid). The contractions were not prevented by inhibitors of thromboxane synthetase or prostacyclin synthetase or lipoxygenase. Pulmonary and femoral veins with or without endothelium relaxed to low, but contracted to high concentrations of prostacyclin and prostaglandin E2. Prostaglandin F2 alpha caused endothelium-independent contractions in both blood vessels. The present study suggests that the endothelium-dependent contractions to arachidonic acid observed in canine veins are mediated by prostanoids other than thromboxane and prostacyclin.
花生四烯酸在犬类动脉中产生内皮依赖性舒张，而在静脉中产生内皮依赖性收缩。在犬类股动脉中，环氧化酶抑制剂可阻止这种舒张。为了确定环氧化酶在花生四烯酸引起的静脉收缩中的作用，将有内皮和无内皮的犬类股静脉及肺内静脉环悬挂于器官浴槽中，并将其设定在等长张力测量的最佳长度。在用去甲肾上腺素收缩的股静脉和肺静脉环中，花生四烯酸使张力呈浓度依赖性增加，去除内皮或用环氧化酶抑制剂（吲哚美辛、甲氯芬那酸或乙酰水杨酸）处理可消除这种增加。血栓素合成酶抑制剂、前列环素合成酶抑制剂或脂氧合酶均不能阻止这种收缩。有内皮和无内皮的肺静脉和股静脉对低浓度的前列环素和前列腺素E2舒张，但对高浓度则收缩。前列腺素F2α在两种血管中均引起非内皮依赖性收缩。本研究提示，在犬类静脉中观察到的对花生四烯酸的内皮依赖性收缩是由血栓素和前列环素以外的前列腺素介导的。
