Segar J L, Hajduczok G, Smith B A, Merrill D C, Robillard J E
Department of Pediatrics, University of Iowa, Iowa City 52242.
Am J Physiol. 1992 Dec;263(6 Pt 2):H1819-26. doi: 10.1152/ajpheart.1992.263.6.H1819.
The purpose of this study was to characterize the developmental changes in baroreflex function during fetal and postnatal life in sheep. Resting mean arterial blood pressure increased significantly from 55 +/- 2 mmHg in fetuses to 86 +/- 3 mmHg in newborn lambs and to 105 +/- 4 mmHg in 4- to 6-wk-old lambs. The sensitivity (gain) of the renal sympathetic nerve activity (RSNA) response to baroreceptor stimulation was greater (P < 0.05) in fetuses (-7.7 +/- 1.9%/mmHg) than in newborn (-2.9 +/- 0.1%/mmHg) and 4- to 6-wk-old lambs (-2.2 +/- 0.2%/mmHg). The threshold and saturation pressures for the baroreflex function curve were lower (P < 0.05) in fetuses (44 +/- 2 and 61 +/- 2 mmHg) than in newborn (59 +/- 4 and 106 +/- 5 mmHg) or 4- to 6-wk-old lambs (78 +/- 5 and 132 +/- 6 mmHg). Similar findings were observed when the heart rate response to baroreceptor stimulation was examined. Additional experiments were performed in newborn and 4- to 6-wk-old lambs to determine whether the rise in arterial blood pressure associated with postnatal maturation contributed to baroreflex resetting. Sustained elevation of arterial blood pressure by 15-20 mmHg for over 90 min did not reset the baroreflex function curve in either newborn or 4- to 6-wk-old lambs.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是描述绵羊胎儿期和出生后生活中压力感受性反射功能的发育变化。静息平均动脉血压从胎儿期的55±2 mmHg显著升高至新生羔羊的86±3 mmHg，以及4至6周龄羔羊的105±4 mmHg。胎儿期肾交感神经活动（RSNA）对压力感受器刺激的反应敏感性（增益）（-7.7±1.9%/mmHg）高于新生羔羊（-2.9±0.1%/mmHg）和4至6周龄羔羊（-2.2±0.2%/mmHg）（P<0.05）。压力感受性反射功能曲线的阈值和饱和压力在胎儿期（44±2和61±2 mmHg）低于新生羔羊（59±4和106±5 mmHg）或4至6周龄羔羊（78±5和132±6 mmHg）（P<0.05）。在检查心率对压力感受器刺激的反应时也观察到了类似的结果。在新生羔羊和4至6周龄羔羊中进行了额外的实验，以确定与出生后成熟相关的动脉血压升高是否有助于压力感受性反射重调定。在新生羔羊和4至6周龄羔羊中，将动脉血压持续升高15至20 mmHg超过90分钟，均未使压力感受性反射功能曲线重调定。（摘要截短于250字）
