Lock J E, Olley P M, Coceani F
Am J Physiol. 1980 May;238(5):H631-8. doi: 10.1152/ajpheart.1980.238.5.H631.
The effects of prostaglandins PGD2, PGE1, PGE2, PGF2 alpha, and PGI2 on pulmonary vascular tone were investigated in normoxic and hypoxic unsedated newborn lambs with chronically implanted flow probes around right and left pulmonary arteries. Prostaglandins were injected into only one pulmonary artery, and direct effects of the compounds were determined by comparing the flow changes in the injected vs. the uninjected lung. PGD2 and PGF2 alpha were direct pulmonary vasoconstrictors, whereas PGE1, PGE2 and PGI2 were direct pulmonary dilators. Hypoxia augmented the vasodilation of PGE1 and PGI2 and diminished the constriction of PGD2 and PGF2 alpha; it also lowered the threshold for PGI2-induced dilation. While the E-type prostaglandins and PGI2 were both local dilators, they differed in that the systemic dilatory effects of the E-type agents exceeded their pulmonary effects, whereas the opposite occurred with PGI2. These results demonstrate that prostaglandins can act locally on pulmonary vascular smooth muscle tone in vivo and that the level of oxygenation or base-line vascular tone influences the pulmonary vascular responses to the PGs. Among the dilator prostaglandins, PGI2 appears to be more effective on the pulmonary rather than the systemic vascular bed under hypoxic conditions.
利用在未镇静的新生羔羊左右肺动脉周围长期植入流量探头的方法，研究了前列腺素PGD2、PGE1、PGE2、PGF2α和PGI2对常氧和低氧状态下肺血管张力的影响。将前列腺素仅注入一条肺动脉，并通过比较注入侧与未注入侧肺的流量变化来确定这些化合物的直接作用。PGD2和PGF2α是直接的肺血管收缩剂，而PGE1、PGE2和PGI2是直接的肺血管扩张剂。低氧增强了PGE1和PGI2的血管舒张作用，减弱了PGD2和PGF2α的血管收缩作用；低氧还降低了PGI2诱导血管舒张的阈值。虽然E型前列腺素和PGI2都是局部血管扩张剂，但它们的不同之处在于，E型药物的全身血管舒张作用超过其肺血管作用，而PGI2则相反。这些结果表明，前列腺素可在体内对肺血管平滑肌张力产生局部作用，并且氧合水平或基线血管张力会影响肺血管对前列腺素的反应。在扩张性前列腺素中，在低氧条件下，PGI2对肺血管床的作用似乎比对全身血管床的作用更有效。
