Bradley L M, Goldstein R E, Feuerstein G, Czaja J F
Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799.
Am J Physiol. 1989 Jan;256(1 Pt 2):H205-12. doi: 10.1152/ajpheart.1989.256.1.H205.
Platelet-activating factor (PAF-acether) is a lipid mediator that can exhibit potent vasoconstrictor influence in the pulmonary vessels. Therefore, the release of PAF-acether during inflammatory conditions in newborns might cause deleterious increases in pulmonary vascular tone. Thirty-four anesthetized open-chest newborn piglets were given 0.01-1 nmol PAF-acether iv. In separate experiments, animals were untreated or treated with either indomethacin (a cyclooxygenase inhibitor), SQ 29548 (a thromboxane receptor blocker), or LY 171883 (a leukotriene receptor blocker). The primary hemodynamic change was a 67 to 1,537% increase in the pulmonary vascular resistance index (PVRI) (P less than 0.01): mean pulmonary artery pressure (PAP) rose significantly at all doses tested, whereas only the largest dose consistently decreased cardiac index. Treatment with indomethacin or SQ 29548 prevented the decrease in cardiac index and attenuated the PAF-acether-induced rises in PAP and PVRI. Vehicle and LY 171883 had no effect. The inhibitory influence of indomethacin and SQ 29548 suggests that an important component of PAF-acether's pulmonary vasoconstrictor action is mediated (at least in the newborn piglet) by cyclooxygenase products, most likely thromboxane.
血小板活化因子（PAF - 乙酰醚）是一种脂质介质，可对肺血管产生强烈的血管收缩作用。因此，新生儿在炎症状态下释放PAF - 乙酰醚可能会导致肺血管张力有害性增加。给34只麻醉开胸的新生仔猪静脉注射0.01 - 1 nmol的PAF - 乙酰醚。在单独的实验中，动物未接受治疗或用吲哚美辛（一种环氧化酶抑制剂）、SQ 29548（一种血栓素受体阻滞剂）或LY 171883（一种白三烯受体阻滞剂）进行治疗。主要的血流动力学变化是肺血管阻力指数（PVRI）增加67%至1537%（P < 0.01）：在所有测试剂量下，平均肺动脉压（PAP）均显著升高，而只有最大剂量持续降低心脏指数。用吲哚美辛或SQ 29548治疗可防止心脏指数下降，并减弱PAF - 乙酰醚诱导的PAP和PVRI升高。溶媒和LY 171883无作用。吲哚美辛和SQ 29548的抑制作用表明，PAF - 乙酰醚肺血管收缩作用的一个重要组成部分（至少在新生仔猪中）是由环氧化酶产物介导的，很可能是血栓素。
