Henning R J, Khalil I
Division of Investigative Medicine, Mt. Sinai Medical Center, Cleveland, OH 44106.
J Auton Nerv Syst. 1989 Oct;28(1):15-25. doi: 10.1016/0165-1838(89)90003-9.
We studied the effects of stimulation of the vagal and also the sympathetic efferent cardiac nerves on left ventricular (LV) relaxation and contraction in 11 anesthetized, open-chest dogs. In each dog, we paced the ventricles at a fixed rate of 120 beats.min-1 and kept the systemic arterial pressure constant. The maximum rate of LV pressure decline, (dP/dt)min, and the time constant of LV isovolumic pressure decline, tau, were used as our indexes of LV relaxation. The maximum rate of LV pressure rise, (dP/dt)max, was used as our measure of LV contractility. Vagal stimulation decreased (dP/dt)min more than (dP/dt)max (P less than 0.01) when examined at frequencies that ranged from 2 to 12 Hz. Vagal stimulation at 12 Hz reduced (dP/dt)min by 26% (P less than 0.001) and increased tau by 57% (P less than 0.0001) but decreased (dP/dt)max by only 20%. Sympathetic stimulation, at frequencies that ranged from 2 to 12 Hz, increased (dP/dt)min more than (dP/dt)max (P less than 0.001). Sympathetic stimulation at 12 Hz increased (dP/dt)min by 130% (P less than 0.0001) whereas it increased (dP/dt)max by 60% (P less than 0.0001). Sympathetic stimulation at 12 Hz decreased tau by 74% (P less than 0.0001). Our studies suggest that cardiac autonomic nerve stimulation affects left ventricular relaxation more than left ventricular contraction.
我们研究了刺激迷走神经以及交感传出心脏神经对11只麻醉开胸犬左心室舒张和收缩的影响。在每只犬中，我们以固定频率120次/分钟对心室进行起搏，并保持体循环动脉压恒定。左心室压力下降的最大速率（dP/dt）min和左心室等容压力下降的时间常数tau作为左心室舒张的指标。左心室压力上升的最大速率（dP/dt）max作为左心室收缩力的指标。当在2至12Hz的频率范围内进行检查时，迷走神经刺激使（dP/dt）min降低的幅度大于（dP/dt）max（P<0.01）。12Hz的迷走神经刺激使（dP/dt）min降低26%（P<0.001），使tau增加57%（P<0.0001），但仅使（dP/dt）max降低20%。交感神经刺激在2至12Hz的频率范围内，使（dP/dt）min增加的幅度大于（dP/dt）max（P<0.001）。12Hz的交感神经刺激使（dP/dt）min增加130%（P<0.0001），而使（dP/dt）max增加60%（P<0.0001）。12Hz的交感神经刺激使tau降低74%（P<0.0001）。我们的研究表明，心脏自主神经刺激对左心室舒张的影响大于对左心室收缩的影响。
