McLaughlin M K, Westney D J
Am J Obstet Gynecol. 1985 Feb 15;151(4):479-83. doi: 10.1016/0002-9378(85)90274-1.
The hind limb vascular responses to angiotensin II and phenylephrine, an alpha-adrenergic agonist, were determined in chronically instrumented pregnant (n = 7) and castrated (n = 6) ewes. On any one day, five doses of one or the other drug were administered directly into the arterial femoral circulation while the perfusion pressure and external iliac blood flow were monitored. The steady-state resistance change (baseline resistance - the resistance calculated during the 3 to 5 minutes of drug infusion) showed a reduction in vascular response to angiotensin II in the pregnant ewes compared to the controls, with no significant differences in response to phenylephrine. When the dynamic (within 40 seconds) rather than the steady-state changes were analyzed, a hyperreactivity to phenylephrine was present in the pregnant animals. These data are an illustration of the complex interactions that are present in the whole-body pressor responses to vasoactive stimuli during pregnancy.
在长期植入仪器的怀孕母羊（n = 7）和去势母羊（n = 6）中，测定了后肢对血管紧张素II和苯肾上腺素（一种α-肾上腺素能激动剂）的血管反应。在任何一天，将五剂这两种药物中的一种直接注入股动脉循环，同时监测灌注压力和髂外血流量。稳态阻力变化（基线阻力 - 在药物输注3至5分钟期间计算出的阻力）显示，与对照组相比，怀孕母羊对血管紧张素II的血管反应降低，而对苯肾上腺素的反应无显著差异。当分析动态（40秒内）而非稳态变化时，怀孕动物对苯肾上腺素存在高反应性。这些数据说明了怀孕期间全身对血管活性刺激的升压反应中存在的复杂相互作用。
