Macdonald A A, Llanos A J, Heymann M A, Rudolph A M
Pflugers Arch. 1981 Jun;390(3):262-4. doi: 10.1007/BF00658273.
We studied the development of responsiveness to pharmacological blockade of parasympathetic, alpha-adrenergic and beta-adrenergic control of the circulation of the pig fetus during the last 30 days of gestation (term is 114 days). Heart rate increased following administration of atropine, the increase in fetuses aged 85-90 days gestation being significantly smaller then at term. Infusion of phentolamine decreased fetal blood pressure, the fall in pressure seen in younger fetuses being less than that observed in fetuses near term. However, when expressed in relation to control pressures, the percentage change was the same at all ages. Propranolol slowed the heart rate of all fetuses with no significant differences between stages of gestation. We conclude that vagal control over the circulation continues to increase during the last month of gestation and that the substantial sympathetic activity seen at the earlier ages studied appeared to show no further development prior to term.
我们研究了妊娠最后30天（足月为114天）猪胎儿循环系统对副交感神经、α-肾上腺素能和β-肾上腺素能控制的药理学阻断反应性的发育情况。给予阿托品后心率增加，妊娠85 - 90天的胎儿心率增加幅度明显小于足月胎儿。静脉输注酚妥拉明可降低胎儿血压，较年轻胎儿的血压下降幅度小于足月胎儿。然而，相对于对照血压而言，各年龄段的百分比变化是相同的。普萘洛尔使所有胎儿的心率减慢，不同妊娠阶段之间无显著差异。我们得出结论，迷走神经对循环系统的控制在妊娠最后一个月持续增强，且在研究的早期阶段所观察到的大量交感神经活动在足月前似乎没有进一步发展。
