Interactions among heart rate, autonomic activity, and arterial pressure upon the multiple repetitive extrasystole threshold in the dog.
Interactions among heart rate, autonomic activity, and arterial pressure upon the multiple repetitive extrasystole threshold in the dog.
复制标题
心率、自主活动和动脉压之间的相互作用对狗多次重复性期前收缩阈值的影响。
DOI：
10.1016/0002-8703(83)90660-9
复制
发表时间：
1983
影响因子：
4.8
通讯作者：
Levy,MN
中科院分区：
文献类型：
--
作者：
Furey3rd,SA;Levy,MN
The effects of heart rate, autonomic stimulation, and arterial blood pressure upon the multiple repetitive extrasystole threshold (MRET) were studied after coronary occlusion in anesthetized dogs. The MRET was unaffected by changes in heart rate. Sympathetic stimulation alone reduced the MRET from 52.4 ± 3.7 (mean ± SEM) to 41.3 ± 2.7 mA. Vagal stimulation alone was without effect. During simultaneous sympathetic and vagal stimulation the threshold was 48.7 ± 3.0 mA. This supports the contention that vagal activity serves mainly to oppose the tendency for sympathetic activity to lower the MRET. Reduction of blood pressure significantly decreased the average MRET from 38.6 ± 2.5 to 34.4 ± 1.8 mA. The presence of a post junctional site for the observed sympathetic-vagal interaction was investigated using isoproterenol infusion and vagal stimulatin. Infusion of isoproterenol lowered the MRET. Vagal stimulation in this situation raised the MRET; the effect varied directly with the rate of isoproterenol infusion. This suggests that part of the vagal effect is exerted postjunctionally; that is, directly upon the myocardial cell and not merely by inhibition of adrenergic transmitter release at sympathetic nerve endings.
