Higuchi M, Murata Y, Miyake Y, Hesser J, Tyner J, Keegan K A, Porto M
Department of Obstetrics and Gynecology, University of California-Irvine School of Medicine, Orange 92668.
Am J Obstet Gynecol. 1987 Oct;157(4 Pt 1):986-90. doi: 10.1016/s0002-9378(87)80101-1.
The influence of norepinephrine on lung fluid flow rate was studied in seven chronically catheterized fetal lambs. Lung fluid was collected through a catheter inserted into the fetal trachea. In six experiments, continuous saline solution infusion for 1 hour followed by equivolumnar norepinephrine (3.0 micrograms/min) for 1 hour via the fetal jugular vein was carried out. In three additional experiments (two fetuses), a 3.0 mg intravenous bolus of propranolol was administered before norepinephrine infusion. Saline solution infusion did not influence the lung fluid flow rate or fetal biophysical and biochemical parameters. Norepinephrine increased fetal blood pressure by 22% and decreased lung fluid flow by 45% from control values. Lung fluid flow rate recovered within 2 hours after the end of the norepinephrine infusion. Pretreatment with propranolol did not alter the results. In addition to previous reports that demonstrated beta-sympathomimetic agonist-enhanced reabsorption of lung fluid from fetal alveolar epithelial cells, our present results suggest that a reduction in fetal lung fluid secretion may be implemented as well through stimulation of alpha-sympathomimetic receptor sites in the pulmonary vasculature.
在七只长期插管的胎儿羔羊中研究了去甲肾上腺素对肺液流速的影响。通过插入胎儿气管的导管收集肺液。在六个实验中，通过胎儿颈静脉连续输注生理盐水1小时，随后等量输注去甲肾上腺素（3.0微克/分钟）1小时。在另外三个实验（两个胎儿）中，在输注去甲肾上腺素之前静脉推注3.0毫克普萘洛尔。输注生理盐水不影响肺液流速或胎儿生物物理和生化参数。去甲肾上腺素使胎儿血压比对照值升高22%，肺液流速降低45%。去甲肾上腺素输注结束后2小时内肺液流速恢复。普萘洛尔预处理不改变结果。除了先前的报告表明β-拟交感神经激动剂可增强胎儿肺泡上皮细胞对肺液的重吸收外，我们目前的结果表明，通过刺激肺血管系统中的α-拟交感神经受体位点，也可能实现胎儿肺液分泌的减少。
