Ventricular-vascular uncoupling by acute conotruncal occlusion in the stage 21 chick embryo.
Ventricular-vascular uncoupling by acute conotruncal occlusion in the stage 21 chick embryo.
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21 期鸡胚急性圆锥干闭塞导致心室血管解偶联。
DOI：
10.1152/ajpheart.1997.273.6.h2861
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Tinney,JP
中科院分区：
文献类型：
--
作者：
Keller,BB;Yoshigi,M;Tinney,JP
对21期鸡胚胎在正常射血（耦合）和急性心室流出道阻塞（非耦合）期间的胚胎心室舒张和收缩功能进行了评价。我们同时用伺服零系统测量心室压力和用视频显微镜测量心室尺寸。实验方案包括：1)基线记录，然后进行急性conotruncal （CT）结扎（n= 15）； 2)基线记录，使用Krebs-Henseleit缓冲液（3 μl）增加预负荷，通过静脉出血减少预负荷，然后进行CT闭塞（n= 20）。心室心外膜横截面积转换为内部体积使用壁容积测量和假设椭球几何产生压力-体积环路。我们用带压力渐近线的单指数衰减函数计算了心室压力下降的时间常数。如前所述，心率不受剧烈改变前负荷或后负荷的影响。CT结扎使收缩压末升高，最大+dP/dt值升高，心室压时间常数下降，舒张末期容量指标减少。因此，胚胎心室具有显著的收缩储备，在体内被心室和动脉循环之间的动态耦合所掩盖。
Embryonic ventricular diastolic and systolic function was evaluated during normal ejection (coupled) and during acute ventricular outflow tract occlusion (uncoupled) in thestage 21chick embryo. We simultaneously measured ventricular pressure with a servo-null system and ventricular dimensions using video microscopy. Experimental protocols included1) baseline recording followed by acute conotruncal (CT) ligation (n= 15) and2) baseline recording, preload increase using Krebs-Henseleit buffer (3 μl), preload reduction via venous hemorrhage, and then CT occlusion (n= 20). Ventricular epicardial cross-sectional area was converted to internal volume using wall volume measures and assuming an ellipsoid geometry to produce pressure-volume loops. We calculated the time constant of ventricular pressure decline using a monoexponential decay function with a pressure asymptote. As previously noted, heart rate was unaffected by acutely altered preload or afterload. CT ligation increased end-systolic pressure, maximal +dP/dt, and the time constant of ventricular pressure decline and decreased stroke volume indexed for end-diastolic volume. Thus the embryonic ventricle has significant contractile reserve masked in vivo by the dynamic coupling between the ventricle and arterial circulation.