Developmental changes in cardiac contractility in fetal and postnatal sheep: in vitro and in vivo.
Developmental changes in cardiac contractility in fetal and postnatal sheep: in vitro and in vivo.
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胎儿和产后绵羊心肌收缩力的发育变化：体外和体内。
DOI：
10.1152/ajpheart.1984.247.3.h371
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
CrenshawJr,C
中科院分区：
文献类型：
--
作者：
Anderson,PA;Glick,KL;Manring,A;CrenshawJr,C
通过使用期外收缩后增强和力、压力和室壁运动测量，在胎儿和出生后绵羊心脏中寻求收缩力的发育变化。使用两种不同的制备方法，离体心肌和慢性仪器羔羊。在孤立的肌肉，以下随年龄的增长显着增加：收缩力，力的最大上升率，和postextrasystolic增强。在出生前的完整心脏中[研究期间，20 +/- 4（SD）天]，心率（HR）显著下降，以下指标显著增加：期外收缩后增强[用左心室（LV）压力（Pmax）的最大上升速率测量]、LV峰值收缩压（LVP）、舒张末期内径（EDD）、收缩末期内径（ESD）和主动脉舒张压。出生后LVP、Pmax、HR、LVEDP、EDD和ESD增加，期外收缩后增强下降。后一种下降在体外没有发现，可能表明与激素或神经刺激有关的收缩性的短暂变化。在随后的出生后几天（6-122天），HR下降，而增强，EDD和ESD显着增加。无论是在体外还是在体内，期外收缩后增强的总体增加都表明收缩力的类似长期变化。这种变化与轻度肥大诱导的变化相似，表明发育和轻度肥大通过共同的机制改变心肌收缩力。
Developmental changes in contractility were sought in the fetal and postnatal sheep heart by using postextrasystolic potentiation and force, pressure, and wall-motion measures. Two different preparations were used, isolated myocardium and the chronically instrumented lamb. In the isolated muscle, the following increased significantly with age: force of contraction, the maximum rate of rise of force, and postextrasystolic potentiation. In the intact heart prior to birth [period of study, 20 +/- 4 (SD) days] heart rate (HR) fell significantly, and the following increased significantly: postextrasystolic potentiation [measured with the maximum rate of rise of left ventricular (LV) pressure (Pmax)], LV peak systolic pressure (LVP), end-diastolic dimension (EDD), end-systolic dimension (ESD), and aortic diastolic pressure. After birth, LVP, Pmax, HR, LVEDP, EDD, and ESD increased and postextrasystolic potentiation fell. The latter fall was not found in vitro and probably demonstrates a transient change in contractility, related to hormonal or neural stimulation. Over the subsequent postnatal days (6-122 days), HR fell while potentiation, EDD, and ESD increased significantly. Both in vitro and in vivo, the overall increase in postextrasystolic potentiation demonstrates a similar long-term change in contractility. The similarity of this change to that induced by mild hypertrophy suggests that development and mild hypertrophy alter myocardial contractility through a common mechanism.