Monheit A G, VanVunakis H, Key T C, Resnik R
Am J Obstet Gynecol. 1983 Feb 1;145(3):290-6. doi: 10.1016/0002-9378(83)90713-5.
The effects of nicotine on uterine and umbilical hemodynamics were studied in seven pregnant ewes equipped with electromagnetic flow probes around the main uterine and common umbilical arteries, and with polyvinyl catheters inserted into the fetal aorta and maternal femoral vessels. Maternal systemic infusions of 1.0 to 1.5 mg/min significantly decreased uterine blood flow by 42% (p less than 0.001) and 32% (p less than 0.05), respectively. However, nicotine infusion rates of 0.5 mg/min, resulting in mean peak maternal nicotine concentrations of 130 +/- 5.0 ng/ml (SE), a value substantially higher than that reported in smoking humans, did not significantly alter uterine or umbilical vascular hemodynamics. Furthermore, at this lower nicotine dose, no alterations were observed in maternal or fetal plasma norepinephrine and epinephrine. The findings suggest either a species difference between sheep and humans in the threshold of catecholamine release to nicotine exposure or the need for repetitive nicotine infusions throughout the day to stimulate the human smoking experience.
在七只怀孕母羊身上研究了尼古丁对子宫和脐血流动力学的影响。这些母羊的主要子宫动脉和脐总动脉周围均安装了电磁流量探头，且在胎儿主动脉和母体股血管中插入了聚乙烯导管。母体以1.0至1.5毫克/分钟的速率进行全身输注时，子宫血流量分别显著降低了42%（p<0.001）和32%（p<0.05）。然而，以0.5毫克/分钟的速率输注尼古丁，导致母体尼古丁平均峰值浓度达到130±5.0纳克/毫升（标准误），该值远高于吸烟人群报告的值，但并未显著改变子宫或脐血管的血流动力学。此外，在这个较低的尼古丁剂量下，母体或胎儿血浆中的去甲肾上腺素和肾上腺素未出现变化。这些发现表明，在对尼古丁暴露的儿茶酚胺释放阈值方面，绵羊和人类之间存在物种差异，或者提示需要在一天中反复输注尼古丁以模拟人类吸烟体验。
