Role of Sympatho-vagal Regulation on Ventricular Arterial Coupling

由于心脏在整个生命周期中持续泵血，因此支持心脏所需的能量变得巨大。虽然许多研究者证明心室与动脉系统的耦合是能量有效的，但自主神经系统在心室动脉耦合中的作用尚不清楚。本研究的目的是阐明交感神经系统和迷走神经系统影响室-动脉耦联的机制。在麻醉、切断迷走神经的狗中，我们分离颈动脉窦并随机改变窦内压（csp），同时测量收缩末期心室弹性（Ees）和有效动脉弹性（Ea）。我们估计了从CSP到Ees和Ea的传递函数。从CSP到Ees的传递函数与从CSP到Ea的传递函数非常相似。这意味着无论何时压力感受性反射 ...更多信息 激活后，Ees和Ea都以类似的时间过程变化。因此，决定心室射血效率的Ea/Ees的比值，无论CSP的变化如何，都不会发生变化。由于Ea/Ees被设定在效率最佳的点，这一观察结果表明，压力感受性反射在维持心室射血效率的同时调节血压。第二年，我们研究了迷走神经系统如何影响心室动脉耦合。在麻醉，交感神经切除兔子，我们电刺激心脏迷走神经，同时测量Ees和Ea。然后，我们估计了从迷走神经刺激到Ees和Ea的传递函数。从迷走神经刺激到Ees的传递函数与从迷走神经刺激到Ea的传递函数非常相似。这意味着迷走神经的调节并没有改变心室与动脉系统的有效耦合，我们的结论是，心室动脉耦合的自主调节发生，使有效的心室射血维持。少

Since the heart continues to pump blood throughout the life time, the amount of energy required to support the heart becomes enormous. Although many investigators demonstrated that ventricular coupling with the arterial system is energeticaly efficient, it is not known the role of the autonomic nervous system in the ventricullar arterial coupling. The purpose of this investigation was to elucidate the mcchanism by which the sympathetic system and vagal system affect the ventricular arterial coupling.In the first year, we investigated how the sympathetic system affects ventricular-arterial coupling. In anesthetized, vagotomized dogs, we isolated the carotid sinuses and altered intrasinus pressurc (csp) randomly while measuring end-systolic ventricular elastance (Ees) and effective arterial elastance (Ea). We estimated transfer functions from CSP to Ees and Ea. The transfer function from CSP to Ees was remarkably similar to that from CSP to Ea. This implies that whenever the baroreflex i … More s activated, both Ees and Ea change with a similar time course. Thus, the ratio of Ea/Ees, that is the determinant of efficiency of ventricular ejection, will remain unaltered irrespective of changes in CSP.Since Ea/Ees is set to a point where the efficiency is fairly optimum, this observation indicated that baroreflex adjusts blood pressure while maintaining efficiency of ventricular ejection.In the second year, we investigated how the vagal system affected ventricular arterial coupling. In anesthetized, sympathectomized rabbits, we electrically stimulated the cardiac vagal nerve while measuring Ees and Ea. We then estimated the transfer functions from vagal stimulation to Ees and to Ea. The transfer function from the vagal stimulation to Ees strikingly resembled that from the vagal stimulation to Ea. This implied that the vagal regulation did not alter efficient coupling of the ventricle with the arterial system.We conclude that the autonomic regulation of ventricular arterial coupling takes place so that efficient ventricular ejection is maintained. Less