Carotid Sinus Baroreceptor Reflex Effects upon Myocardial Contractility
Carotid Sinus Baroreceptor Reflex Effects upon Myocardial Contractility
复制标题
颈动脉窦压力感受器反射对心肌收缩力的影响
作者：
H. De Geest;M. N. Levy;H. Zieske
刺激颈动脉窦压力感受器对左心房和心室性能的反射效应已在张力不足和等容左心制剂中进行了研究，该制剂受神经支配，但在液压上完全隔离。心率、动脉阻抗、静脉回流和循环儿茶酚胺水平的反射变化被阻止影响心脏功能。在生长张力准备中，刺激颈动脉窦压力感受器会降低主动脉压、心输出量和左心室外部做功。同时，平均左心房压力明显升高。在等容制备中，观察到左心室收缩峰值压降低。心房和心室动力学的这些变化主要归因于交感神经系统介导的直接作用于心房和心室心肌的反射性负性肌力作用。未观察到等容左心室扩张性的明确变化，尽管在生长张力准备中不能排除这种情况。冠状血管床的主要变化不被认为是观察到的心房和心室动力学变化的原因。
The reflex effects of stimulation of the carotid sinus baroreceptors on left atrial and ventricular performance have been studied in an auxotonic and an isovolumetric left heart preparation, which was innervated, though completely isolated hydraulically. Reflex changes of heart rate, arterial impedance, venous return, and level of circulating catecholamines were prevented from influencing cardiac performance. In the auxotonic preparation, stimulation of the carotid sinus baroreceptors decreased aortic pressure, cardiac output, and external left ventricular work. Simultaneously, mean left atrial pressure rose definitely. In the isovolumetric preparation, a decrease of the left ventricular peak systolic pressure was observed. These changes in atrial and ventricular dynamics were attributed primarily to a reflex negative inotropic effect directly upon the atrial and ventricular mycardium, mediated by the sympathetic nervous system. No definite changes in distensibility of the isovolumetric left ventricle were observed, although this could not be excluded in the auxotonic preparation. Primary changes in the coronary vascular bed were not considered to be responsible for the observed changes in atrial and ventricular dynamics.