Brooks W W, Verrier R L, Lown B
Cardiovasc Res. 1981 Feb;15(2):92-7. doi: 10.1093/cvr/15.2.92.
The effect of sympathetic and parasympathetic stimulation on the vulnerable period threshold and the protective zone was studied in chloralose-anaesthetised dogs. Sympathetic stimulation substantially decreased the repetitive extrasystole threshold and shifted the timing of the protective zone earlier into diastole. Vagus nerve excitation exerted the opposite effect on both electrophysiological properties. During concurrent sympathetic nerve stimulation, the changes produced by vagal activation were accentuated. These findings suggest that parasympathetic influences on the protective zone are due, in part, to an antagonism of adrenergic effects on ventricular electrical properties.
在水合氯醛麻醉的犬中研究了交感神经和副交感神经刺激对易损期阈值和保护区的影响。交感神经刺激显著降低了重复性期前收缩阈值，并将保护区的时间提前至舒张期。迷走神经兴奋对这两种电生理特性产生相反的影响。在交感神经同时刺激期间，迷走神经激活所产生的变化会加剧。这些发现表明，副交感神经对保护区的影响部分归因于对肾上腺素能对心室电特性的作用的拮抗。
