Quigley Karen S, Myers Michael M, Shair Harry N
Department of Psychiatry, UMDNJ-New Jersey Medical School, Newark, NJ 07107, and East Orange VA Medical Center, War Related Illness Center, Stop #129, 385 Tremont Ave., East Orange, NJ 07018, United States.
Auton Neurosci. 2005 Aug 31;121(1-2):26-32. doi: 10.1016/j.autneu.2005.05.003.
The baroreceptor-heart period reflex was assessed in conscious, freely behaving rat pups on postnatal days 6 and 14. The baroreceptor-heart period reflex was elicited using the alpha1-adrenergic agonist phenylephrine to increase blood pressure and the vasodilator, sodium nitroprusside, to decrease blood pressure. The autonomic effects of the baroreceptor manipulations were determined using pharmacological autonomic blockade. The data demonstrate that vasoconstriction produces a potent baroreflex-mediated bradycardia as early as postnatal day 6, which had previously been demonstrated only in anesthetized pups. In the anesthetized pup, the bradycardia is mediated by vagal activation, while we demonstrate that both vagal activation and sympathetic withdrawal occur in unanesthetized animals. In addition, the results replicate previous findings in rats demonstrating minimal cardiac sympathetic activation or vagal withdrawal following vasodilation during the first week of life, but substantial baroreflex-mediated tachycardia by the second week.
在出生后第6天和第14天对清醒、自由活动的幼鼠进行压力感受器-心动周期反射评估。使用α1肾上腺素能激动剂去氧肾上腺素升高血压以及血管扩张剂硝普钠降低血压来引发压力感受器-心动周期反射。通过药理学自主神经阻滞来确定压力感受器操作的自主神经效应。数据表明，早在出生后第6天，血管收缩就会产生由压力反射介导的强烈心动过缓，此前仅在麻醉幼鼠中得到证实。在麻醉幼鼠中，心动过缓由迷走神经激活介导，而我们证明在未麻醉动物中迷走神经激活和交感神经抑制均会发生。此外，结果重复了先前在大鼠中的发现，即在出生后第一周血管舒张后心脏交感神经激活或迷走神经抑制最小，但到第二周会出现明显的压力反射介导的心动过速。
