一氧化氮支持妊娠中期胎羊的右心室血流优势和全身氧利用。
NO supports right ventricular flow dominance and whole body O(2) utilization in midgestation fetal lambs.
作者信息
Smolich J J
机构信息
Centre for Heart and Chest Research, Department of Medicine and Institute of Reproduction and Development, Monash University, Clayton, Victoria, Australia 3168.
出版信息
Am J Physiol Regul Integr Comp Physiol. 2001 Apr;280(4):R1016-22. doi: 10.1152/ajpregu.2001.280.4.R1016.
It is unknown if nitric oxide (NO) modulates the relative levels of left (LV) and right (RV) ventricular output, fetal O2 consumption, or blood flow distribution between the body and placenta at midgestation. To address these questions, six fetal lambs were instrumented at 89-96 days gestation (term 147 days), and blood flows were measured with radioactive microspheres 3-4 days later at baseline and after inhibition of NO synthesis with 10 mg/kg (L-NNA10) and 25 mg/kg (L-NNA25) N(omega)-nitro-L-arginine. LV output fell by 74 +/- 15 ml. min(-1). kg(-1) at L-NNA10 (P < 0.005), whereas RV output decreased by 90 +/- 18 ml. min(-1). kg(-1) at L-NNA10 (P < 0.02) and by a further 80 +/- 22 ml. min(-1). kg(-1) at L-NNA25 (P < 0.05). As a result, RV output exceeded LV output at baseline (P = 0.03) and L-NNA10 (P < 0.02) but not at L-NNA25. Fetal body blood flow fell by 95 +/- 25 ml. min(-1). kg(-1) at L-NNA10 (P < 0.01), but because placental blood flow decreased by 70 +/- 22 ml. min(-1). kg(-1) at L-NNA10 (P < 0.01) and a further 71 +/- 21 ml. min(-1). kg(-1) at L-NNA25 (P < 0.01), the fetal body-to-placental blood flow ratio was near unity at baseline and L-NNA10 but rose to 1.5 +/- 0.3 at L-NNA25 (P < 0.05). In association with these flow changes, fetal O2 consumption declined by 1.4 +/- 0.3 ml. min(-1). kg(-1) at L-NNA10 (P < 0.05) and by a further 1.5 +/- 0.6 ml. min(-1). kg(-1) at L-NNA25 (P < 0.02). These findings suggest that, in midgestation fetal lambs, NO supports an RV flow dominance, whole body O2 utilization, and the maintenance of a near-equal fetoplacental blood flow distribution.
尚不清楚一氧化氮（NO）是否会调节妊娠中期左心室（LV）和右心室（RV）输出的相对水平、胎儿耗氧量或身体与胎盘之间的血流分布。为了解决这些问题，对6只妊娠89 - 96天（足月为147天）的胎羊进行了仪器植入，3 - 4天后在基线状态以及用10mg/kg（L - NNA10）和25mg/kg（L - NNA25）的N（ω）-硝基-L-精氨酸抑制NO合成后，用放射性微球测量血流。在L - NNA10时，左心室输出量下降了74±15ml·min⁻¹·kg⁻¹（P < 0.005），而在L - NNA10时右心室输出量下降了90±18ml·min⁻¹·kg⁻¹（P < 0.02），在L - NNA25时又进一步下降了80±22ml·min⁻¹·kg⁻¹（P < 0.05）。结果，在基线状态（P = 0.03）和L - NNA10时（P < 0.02）右心室输出量超过左心室输出量，但在L - NNA25时并非如此。在L - NNA10时，胎儿身体血流量下降了95±25ml·min⁻¹·kg⁻¹（P < 0.01），但由于在L - NNA10时胎盘血流量下降了70±22ml·min⁻¹·kg⁻¹（P < 0.01），在L - NNA25时又进一步下降了71±21ml·min⁻¹·kg⁻¹（P < 0.01），所以胎儿身体与胎盘的血流量比值在基线状态和L - NNA10时接近1，但在L - NNA25时升至1.5±0.3（P < 0.05）。与这些血流变化相关的是，在L - NNA10时胎儿耗氧量下降了1.4±0.3ml·min⁻¹·kg⁻¹（P < 0.05），在L - NNA25时又进一步下降了1.5±0.6ml·min⁻¹·kg⁻¹（P < 0.02）。这些发现表明，在妊娠中期的胎羊中，NO支持右心室血流优势、全身氧气利用以及维持胎儿与胎盘血流量近乎相等的分布。
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