Resnik R, Conover W B, Key T C, Van Vunakis H
Am J Obstet Gynecol. 1985 Apr 1;151(7):885-91. doi: 10.1016/0002-9378(85)90666-0.
In order to simulate human smoking, experiments were designed to determine what dose of nicotine in the pregnant sheep would produce those plasma nicotine concentrations observed in human smokers and to measure uterine blood flow and plasma catecholamines in response to repetitive exposure (every 30 minutes) to that nicotine dose. Utilizing seven chronically catheterized pregnant sheep equipped with electromagnetic flow probes around both uterine arteries, we observed that a nicotine dose of 0.2 mg/min for 5 minutes results in mean plasma nicotine concentrations of 23.1 +/- 1.1 ng/ml SEM (n = 17) immediately following infusion. This dose of nicotine was then infused every 30 minutes for 4 hours, and aliquots of blood were drawn immediately before and after nicotine infusion for determination of plasma catecholamines. No significant alterations in plasma epinephrine and norepinephrine were observed throughout the experiments (n = 8), and no significant changes in uterine blood flow occurred at any time during the experiment (n = 30). We conclude that there is a species difference between sheep and man with respect to the nicotinic threshold for catecholamine release.
为了模拟人类吸烟，设计了实验来确定给怀孕绵羊注射何种剂量的尼古丁会产生在人类吸烟者中观察到的血浆尼古丁浓度，并测量反复暴露于该尼古丁剂量（每30分钟一次）时的子宫血流量和血浆儿茶酚胺。利用七只长期插管的怀孕绵羊，在其两条子宫动脉周围均安装了电磁流量探头，我们观察到，以0.2毫克/分钟的剂量注射尼古丁5分钟后，输注结束时血浆尼古丁平均浓度为23.1±1.1纳克/毫升标准误（n = 17）。然后每30分钟输注该剂量的尼古丁，持续4小时，在每次尼古丁输注前后立即采集血样以测定血浆儿茶酚胺。在整个实验过程中未观察到血浆肾上腺素和去甲肾上腺素的显著变化（n = 8），并且在实验期间的任何时间子宫血流量均未发生显著变化（n = 30）。我们得出结论，绵羊和人类在儿茶酚胺释放的烟碱阈值方面存在物种差异。
