Stress Resilience and the Dynamic Regulation of Glucocorticoids
Stress Resilience and the Dynamic Regulation of Glucocorticoids
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应激恢复与糖皮质激素的动态调节
DOI：
10.1093/icb/icz087
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发表时间：
2019
影响因子：
2.6
通讯作者：
Zimmer, Cedric
中科院分区：
文献类型：
--
作者：
Vitousek, Maren N.;Taff, Conor C.;Ryan, Thomas A.;Zimmer, Cedric
脊椎动物通过快速升高糖皮质激素（GC）水平来应对各种压力源。这种反应引发的生理和行为变化对于应对各种挑战至关重要。然而，同样的过程在应对直接威胁方面非常有价值，但随着时间的推移，也可能造成巨大的损害。除了长期暴露于应激激素的病理影响之外，即使相对短暂的升高也会损害对健康至关重要的各种行为和生理过程的表达，包括性行为、父母行为和免疫功能。因此，快速有效地终止对压力的短期反应的能力可能是动态环境中生存和繁殖的基础。在这里，我们回顾了通过负反馈终止压力反应的能力的变化是压力应对能力的重要组成部分的证据。我们认为，应对能力也可能受到 GC 动态调节变化的影响，特别是快速开启和关闭压力反应的能力。迄今为止，大多数对这些性状的适应性影响的测试都集中在经历严重或长期压力源的生物体上。在这里，我们使用从树燕 (Tachycineta bicolor) 的长期研究中收集的数据来测试负反馈的变化或 GC 调节的其他措施是否可以预测非长期压力种群的健康组成部分。我们发现不同健身成分与负反馈强度之间的关系相对一致，但通常较弱。具有强烈应激反应和强烈负反馈的个体的繁殖成功率最高。我们没有看到负反馈与成体或雏鸟生存之间关系的一致证据：负反馈保留在雏鸟和成体生存的最佳支持模型中，但在三项生存相关分析中的两项中，仅拦截模型仅获得稍少的支持。负反馈和压力引起的 GC 水平（但不是基线 GC）都是单独可重复的。这些 GC 活性的测量在不同年龄和生命史阶段之间并不一致，表明它们是独立调节的。总体而言，这里看到的模式与预测一致，即负反馈和 GC 的动态调节是压力应对能力的重要组成部分，但在生殖期具有强烈负反馈的健康益处可能主要体现在暴露于慢性或重复压力源的个体中。
Vertebrates respond to a diversity of stressors by rapidly elevating glucocorticoid (GC) levels. The changes in physiology and behavior triggered by this response can be crucial for surviving a variety of challenges. Yet the same process that is invaluable in coping with immediate threats can also impose substantial damage over time. In addition to the pathological effects of long-term exposure to stress hormones, even relatively brief elevations can impair the expression of a variety of behaviors and physiological processes central to fitness, including sexual behavior, parental behavior, and immune function. Therefore, the ability to rapidly and effectively terminate the short-term response to stress may be fundamental to surviving and reproducing in dynamic environments. Here we review the evidence that variation in the ability to terminate the stress response through negative feedback is an important component of stress coping capacity. We suggest that coping capacity may also be influenced by variation in the dynamic regulation of GCs—specifically, the ability to rapidly turn on and off the stress response. Most tests of the fitness effects of these traits to date have focused on organisms experiencing severe or prolonged stressors. Here we use data collected from a long-term study of tree swallows (Tachycineta bicolor) to test whether variation in negative feedback, or other measures of GC regulation, predict components of fitness in non-chronically stressed populations. We find relatively consistent, but generally weak relationships between different fitness components and the strength of negative feedback. Reproductive success was highest in individuals that both mounted a robust stress response and had strong negative feedback. We did not see consistent evidence of a relationship between negative feedback and adult or nestling survival: negative feedback was retained in the best supported models of nestling and adult survival, but in two of three survival-related analyses the intercept-only model received only slightly less support. Both negative feedback and stress-induced GC levels—but not baseline GCs—were individually repeatable. These measures of GC activity did not consistently covary across ages and life history stages, indicating that they are independently regulated. Overall, the patterns seen here are consistent with the predictions that negative feedback—and the dynamic regulation of GCs—are important components of stress coping capacity, but that the fitness benefits of having strong negative feedback during the reproductive period are likely to manifest primarily in individuals exposed to chronic or repeated stressors.