Taylor B J, Fewell J E, Kearns G L
Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock 72205.
Pediatr Res. 1988 May;23(5):513-8. doi: 10.1203/00006450-198805000-00016.
We investigated the effect of aerosolized cromolyn sodium (CS) on the pulmonary vascular response to isocapneic alveolar hypoxia in chronically instrumented lambs aged 11-12 days. Each lamb underwent two operations: chest instrumentation for measurements of pulmonary arterial, systemic arterial, and left atrial pressures, and pulmonary blood flow; and a tracheotomy for drug administration. The animals were recovered 3 days before study. Each lamb received an aerosol of normal saline (placebo) and CS in paired experiments 24 h apart. In the first set of experiments (n = 8), placebo or CS (30 mg) was given, followed by four 15-min epochs of alveolar hypoxia (8% O2, 5% CO2, 87% N2) each separated by 30 min of alveolar normoxia (21% O2). During hypoxia after both placebo and CS, pulmonary arterial pressure and resistance increased. This response was unchanged with repeated epochs. In the second set of experiments (n = 8), normal saline or CS (30 mg) was administered three times over a 90-min period, followed by one 15-min epoch of hypoxia. Pulmonary arterial pressure and resistance increased during hypoxia after placebo, but did not change after CS. Thus, the single dose of aerosolized CS did not alter the pulmonary vascular response to alveolar hypoxia, whereas the triple dose of CS attenuated the response. Additionally, the pulmonary vascular response to hypoxia alone was not altered by repeated exposures to hypoxia. We conclude that CS interferes with the mechanism(s) responsible for hypoxic pulmonary vasoconstriction in newborn lambs.
我们研究了雾化色甘酸钠（CS）对11 - 12日龄慢性植入仪器的羔羊在等碳酸血症性肺泡缺氧时肺血管反应的影响。每只羔羊接受两次手术：胸部植入仪器以测量肺动脉、体动脉和左心房压力以及肺血流量；以及进行气管切开术用于给药。在研究前3天让动物恢复。在配对实验中，每只羔羊在间隔24小时的时间里分别接受生理盐水（安慰剂）和气溶胶化CS。在第一组实验（n = 8）中，给予安慰剂或CS（30毫克），随后进行四个15分钟的肺泡缺氧期（8%氧气、5%二氧化碳、87%氮气），每个缺氧期之间间隔30分钟的肺泡常氧期（21%氧气）。在给予安慰剂和CS后的缺氧期间，肺动脉压力和阻力均升高。重复缺氧期后这种反应没有变化。在第二组实验（n = 8）中，在90分钟内三次给予生理盐水或CS（30毫克），随后进行一个15分钟的缺氧期。给予安慰剂后缺氧期间肺动脉压力和阻力升高，但给予CS后没有变化。因此，单剂量雾化CS并未改变肺血管对肺泡缺氧的反应，而三剂量CS减弱了这种反应。此外，单独缺氧时的肺血管反应不会因重复暴露于缺氧而改变。我们得出结论，CS干扰了新生羔羊中负责低氧性肺血管收缩的机制。
