The chronically instrumental ewe: a model for studying vascular reactivity to angiotensin II in pregnancy.
The chronically instrumental ewe: a model for studying vascular reactivity to angiotensin II in pregnancy.
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长期工具性母羊：研究妊娠期血管紧张素 II 血管反应性的模型。
DOI：
10.1172/jci110057
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
GantJr,NF
中科院分区：
文献类型：
--
作者：
Rosenfeld,CR;GantJr,NF
血管对血管紧张素II(AII)的全身性升压作用的抵抗力在妊娠期间正常发育。为了确定母羊是否可以提供一个合适的动物模型来研究这种反应的机制(仅限于妊娠)，我们研究了未麻醉的、长期使用器械的未怀孕和怀孕的绵羊，妊娠68-143d。在这些研究中，建立了平均动脉压和子宫血流量变化的剂量-反应曲线。连续输注AII的升压反应随AII剂量的增加而增加(P<0.001)，R分别为0.943和0.879。然而，怀孕的动物对AII的升压作用不敏感，每公斤需要0.016微克的AII才能引起平均动脉压升高20 mm HG，而未怀孕的动物需要0.009微克。在P<0.001的情况下，回归线的斜率和截距不同。在怀孕动物中，还测定了子宫血流量的剂量-反应曲线。当AII剂量低于每公斤0.016微克/分钟时，可以观察到子宫血流量的增加，而更大的剂量会导致逐渐严重的血流量下降。因此，母羊有可能作为一种适合于进一步研究AII引起的独特的妊娠修饰的全身和子宫胎盘血管反应的动物模型。
Vascular refractoriness to the systemic pressor effects of angiotension II (AII) develops normally during human pregnancy. To ascertain if the ewe might provide a suitable animal model to study the mechanisms responsible for this response (unique to pregnancy) we studied this phenomenon in unanesthetized, chronically instrumented nonpregnant and pregnant sheep, 68-143 d gestation. In these studies dose-response curves were established for changes in both mean arterial pressure and uterine blood flow. The pressor response to continuous infusions of AII increases as a function of the dose of AII in both nonpregnant and pregnant animals (P less than 0.001), R = 0.943 and 0.879, respectively. However, the pregnant animals were refractory to the pressor effects of AII, requiring 0.016 microgram of AII/min per kg to elicit a 20 mm HG rise in mean arterial pressure, in contrast to 0.009 for nonpregnant animals. The slope and intercept for the regression lines are different at P less than 0.001. In pregnant animals the dose-response curve for uterine blood flow was also determined. Increases in uterine blood flow were observed at doses of AII less than 0.016 microgram/min per kg, while larger doses resulted in a progressively greater reduction in blood flow. It appears likely that the ewe may serve as an animal model suitable for the further study of the unique pregnancy-modified systemic and uteroplacental vascular responses elicited by AII.