Sgoifo A, De Boer S F, Buwalda B, Korte-Bouws G, Tuma J, Bohus B, Zaagsma J, Koolhaas J M
Department of Animal Physiology, Institute for Behavioral and Cognitive Neurosciences, University of Groningen, 9750 AA Haren, The Netherlands.
Am J Physiol. 1998 Aug;275(2):H460-6. doi: 10.1152/ajpheart.1998.275.2.H460.
An increased activity of the sympathetic nervous system is an important factor in the genesis of ventricular arrhythmias. Changes in average R-R interval, R-R interval variability (indirect measure of sympathovagal balance), occurrence of arrhythmias, and plasma norepinephrine concentrations were measured during a social stress episode (defeat) in two strains of rats, Wistar and wild type, which were supposed to differ in their autonomic stress responsiveness. Electrocardiograms were telemetrically recorded, and blood samples were withdrawn through jugular vein catheters from healthy, freely moving animals. R-R interval variability was estimated by the following time-domain parameters: the standard deviation of the mean R-R interval, the coefficient of variance, and the root mean square of successive differences in R-R interval. Average R-R interval and R-R interval variability measures, as well as plasma norepinephrine concentrations, indicated a higher sympathetic tone, a larger sympathetic responsiveness, and a lower parasympathetic antagonism after sympathetic activation in wild-type animals, which also showed a much higher incidence of arrhythmias (ventricular premature beats), compared with Wistar rats. These two strains might represent a valuable experimental model for studying the mechanisms (cellular/electrophysiological) responsible for the susceptibility to arrhythmias in healthy individuals exposed to stressful situations.
交感神经系统活性增加是室性心律失常发生的一个重要因素。在社会应激事件（失败）期间，对Wistar大鼠和野生型大鼠这两种自主神经应激反应性可能存在差异的大鼠品系，测量平均R-R间期、R-R间期变异性（交感迷走神经平衡的间接指标）、心律失常的发生情况以及血浆去甲肾上腺素浓度。通过遥测记录心电图，并从健康、自由活动的动物经颈静脉导管采集血样。R-R间期变异性通过以下时域参数进行估计：平均R-R间期的标准差、变异系数以及R-R间期连续差值的均方根。平均R-R间期和R-R间期变异性测量值以及血浆去甲肾上腺素浓度表明，与Wistar大鼠相比，野生型动物在交感激活后具有更高的交感神经张力、更大的交感反应性以及更低的副交感拮抗作用，其心律失常（室性早搏）的发生率也高得多。这两个品系可能是研究在应激情况下健康个体心律失常易感性的机制（细胞/电生理）的有价值的实验模型。
