Kadowitz P J, Hyman A L
Circ Res. 1977 Mar;40(3):282-7. doi: 10.1161/01.res.40.3.282.
We evaluated the effects of an analogue of the prostaglandin endoperoxide, PGH2, in the canine pulmonary vascular bed. The analogue increased pulmonary arterial pressure whereas cardiac output and left atrial pressure were unchanged. Although pulmonary vascular resistance was increased markedly, only small increases in systemic vascular resistance were observed. In experiments in which blood flow to a lobe was maintained constant, the analogue produced dose-related increases in lobar arterial and small vein pressure but little change in left atrial pressure. These data suggest that the analogue increased resistance to flow by constricting intrapulmonary veins and upstream vessels presumed to be small arteries. The increase in resistance was similar when the lung was perfused with dextran or with blood. In addition, the analogue increased inflation pressure; however, similar increments in vascular resistance were obtained in ventilated and nonventilated lung lobes. Indomethacin, in doses which abolished responses to arachidonic acid, did not attenuate the response to the analogue. These results suggest that interaction with formed elements, increases in airway tone, or stimulation of prostaglandin synthesis contribute little if anything to the pressor response to the analogue. These data show that the analogue is far more potent than the bisenoic prostaglandins in the pulmonary vascular bed and suggest that endoperoxides may represent an active form of the prostaglandins in the lung.
我们评估了前列腺素内过氧化物PGH2的类似物对犬肺血管床的影响。该类似物可使肺动脉压升高，而心输出量和左心房压未发生变化。尽管肺血管阻力显著增加，但全身血管阻力仅出现小幅升高。在维持肺叶血流量恒定的实验中，该类似物使肺叶动脉压和小静脉压呈剂量依赖性升高，但左心房压变化不大。这些数据表明，该类似物通过收缩肺内静脉和推测为小动脉的上游血管来增加血流阻力。用右旋糖酐或血液灌注肺时，阻力增加情况相似。此外，该类似物可使充气压力升高；然而，在通气和未通气的肺叶中，血管阻力的增加幅度相似。吲哚美辛剂量可消除对花生四烯酸的反应，但并未减弱对该类似物的反应。这些结果表明，与血细胞成分相互作用、气道张力增加或前列腺素合成刺激对该类似物的升压反应几乎没有贡献。这些数据表明，该类似物在肺血管床中的作用比双烯前列腺素强得多，提示内过氧化物可能代表肺中前列腺素的一种活性形式。
