Early Origins of Adult Health Research Group, Health and Biomedical Innovation, UniSA: Clinical and Health Sciences, University of South Australia, Adelaide, SA, Australia.
J Physiol. 2021 Feb;599(4):1307-1318. doi: 10.1113/JP280693. Epub 2020 Dec 27.
Chronic hypoxaemia is associated with intrauterine growth restriction (IUGR) and a predisposition to the development of hypertension in adult life. IUGR fetuses exhibit a greater reliance on α-adrenergic activation for blood pressure regulation. The fetal blood pressure response to post-ganglionic blockade is not different between control and IUGR fetuses. The decrease in mean arterial pressure is greater in the IUGR sheep fetus after α-adrenergic receptor blockade at the level of the vasculature and this is inversely related to fetal . The increased reliance that the IUGR fetus has on α-adrenergic activation for maintenance of mean arterial pressure is not a result of increased post-ganglionic sympathetic activation.
Intrauterine growth restriction (IUGR) is associated with an increased risk of cardiovascular disease in adult life. Placental restriction (PR) in sheep results in chronic hypoxaemia and early onset IUGR with increased circulating plasma noradrenaline concentrations. These IUGR fetuses exhibit a greater decrease in mean arterial pressure (MAP) during α-adrenergic blockade. We aimed to determine the role of post-ganglionic sympathetic activation with respect to regulating MAP in IUGR fetal sheep. PR was induced by carunclectomy surgery prior to conception. Fetal vascular catheterization was performed at 110-126 days gestational age (GA) (term, 150 days) in nine control and seven PR-IUGR fetuses. The fetal blood pressure response to both a post-ganglionic and an α-adrenergic receptor blocker was assessed at 116-120 days GA and/or 129-131 days GA. The effect of both post ganglionic and α-adrenergic blockade on fetal blood pressure was then compared between control and IUGR fetuses at both GAs. There was no difference in the effect of post-ganglionic blockade on MAP in control and IUGR fetal sheep at either 116-120 days GA or 129-131 days GA. α-adrenergic receptor blockade decreased MAP to the same extent in both control and IUGR fetuses at 116-120 days GA. At 129-131 days GA, the drop in MAP in response to α-adrenergic receptor blockade was greater in IUGR fetuses than controls. There was a significant inverse relationship between the drop in MAP in response to α-adrenergic receptor blockade at both GAs with fetal . Thus, the increased dependence on α-adrenergic activation for blood pressure regulation in the chronically hypoxaemic IUGR fetus is not a result of increased post-ganglionic sympathetic activation.
慢性低氧血症与宫内生长受限（IUGR）和成年后高血压易感性有关。IUGR 胎儿对 α-肾上腺素能激活的血压调节有更大的依赖性。在控制和 IUGR 胎儿中，节后神经阻断后胎儿血压的反应没有差异。在血管水平阻断 α-肾上腺素受体后，IUGR 绵羊胎儿的平均动脉压下降幅度更大，这与胎儿体重呈负相关。IUGR 胎儿对 α-肾上腺素能激活维持平均动脉压的依赖增加并不是由于节后交感神经激活增加所致。
宫内生长受限（IUGR）与成年后心血管疾病的风险增加有关。绵羊胎盘限制（PR）导致慢性低氧血症和早期 IUGR，循环血浆去甲肾上腺素浓度增加。这些 IUGR 胎儿在 α-肾上腺素能阻断期间平均动脉压（MAP）下降幅度更大。我们旨在确定节后交感神经激活在调节 IUGR 胎儿绵羊 MAP 中的作用。在受孕前通过 carunclectomy 手术诱导 PR。在 110-126 天妊娠龄（GA）（足月 150 天）时对 9 只对照和 7 只 PR-IUGR 胎儿进行胎儿血管导管插入术。在 116-120 天 GA 和/或 129-131 天 GA 时评估胎儿对节后和 α-肾上腺素能受体阻滞剂的血压反应。然后在两个 GA 时比较对照和 IUGR 胎儿之间节后和 α-肾上腺素能阻断对胎儿血压的影响。在 116-120 天 GA 或 129-131 天 GA 时，对照和 IUGR 胎儿的节后阻断对 MAP 的影响没有差异。在 116-120 天 GA 时，α-肾上腺素能受体阻断同样降低了对照和 IUGR 胎儿的 MAP。在 129-131 天 GA 时，IUGR 胎儿对 α-肾上腺素能受体阻断的 MAP 下降幅度大于对照。在两个 GA 时，对 α-肾上腺素能受体阻断的 MAP 下降幅度与胎儿体重呈显著负相关。因此，慢性低氧血症 IUGR 胎儿对 α-肾上腺素能激活的血压调节依赖性增加不是由于节后交感神经激活增加所致。
