Stress exposure is an important risk factor for psychiatric and cardiovascular disorders. Two phenotypes related to coping with stress can be observed in rodents that experience chronic social defeat stress (SDS): susceptible, showing social avoidance and behavioral changes related to depression, and resilient, showing none of these alterations. Moreover, a strong correlation exists between depression and the development of or mortality due to cardiovascular diseases. Nevertheless, little is known about cardiovascular alterations related to SDS exposure in those phenotypes or their correlation with depressive-like behaviors. Using a chronic SDS protocol followed by the social interaction test, we identified Wistar rats as resilient or susceptible to SDS. Susceptible animals showed increased depressive-like behaviors with resting tachycardia and decreased heart rate variability (HRV) due to increased sympathetic tone in the heart and a less effective baroreflex. In contrast, resilient rats were protected from these alterations by increased vagal tone, resulting in greater HRV values. To our knowledge, our study is the first to indicate that harmful cardiovascular outcomes are related to depressive-like behaviors in susceptible rats and to suggest a mechanism by which resilient rats are protected from these changes. Also, our results suggest that enhanced HRV and vagal tone may be an important trait in resilient individuals.

压力暴露是精神和心血管疾病的重要危险因素。在经历慢性社交挫败压力（SDS）的啮齿动物中，可以观察到两种与应对压力有关的表型：易感，显示出与抑郁症相关的社交回避和行为变化；以及韧性，显示出这些变化均没有。此外，抑郁与心血管疾病的发展或死亡率之间存在很强的相关性。然而，对于那些表型中与SDS暴露相关的心血管改变或它们与抑郁样行为的相关性知之甚少。使用慢性SDS方案，然后进行社交互动测试，我们确定了Wistar大鼠是有弹性的或易患SDS。易感动物表现出与静息性心动过速有关的抑郁样行为增加，并且由于心脏交感神经增强和压力反射效率降低而导致心率变异性（HRV）降低。相反，迷走神经张力增加可保护有弹性的大鼠免受这些改变，从而导致更高的HRV值。据我们所知，我们的研究首次表明有害的心血管结局与易感大鼠的抑郁样行为有关，并提出了保护弹性大鼠免受这些变化影响的机制。同样，我们的结果表明，增强的HRV和迷走神经张力可能是韧性个体的重要特征。增强的迷走神经张力可保护有弹性的大鼠免受这些改变，从而导致更高的HRV值。据我们所知，我们的研究首次表明有害的心血管结局与易感大鼠的抑郁样行为有关，并提出了保护弹性大鼠免受这些变化影响的机制。同样，我们的结果表明，增强的HRV和迷走神经张力可能是韧性个体的重要特征。增强的迷走神经张力可保护有弹性的大鼠免受这些改变，从而导致更高的HRV值。据我们所知，我们的研究首次表明有害的心血管结局与易感大鼠的抑郁样行为有关，并提出了保护弹性大鼠免受这些变化影响的机制。同样，我们的结果表明，增强的HRV和迷走神经张力可能是韧性个体的重要特征。