Spencer Karen A, Evans Neil P, Monaghan Patricia
Division of Environmental and Evolutionary Biology, University of Glasgow, Glasgow, United Kingdom.
Endocrinology. 2009 Apr;150(4):1931-4. doi: 10.1210/en.2008-1471. Epub 2008 Dec 18.
There is growing international interest in how environmental conditions experienced during development can shape adult phenotypes and the extent to which such induced changes are adaptive. One physiological system that links an individual to changes in environmental circumstances during development is the hypothalamic-pituitary-adrenal axis. Mammalian studies have linked early postnatal stress to later changes in the hypothalamic-pituitary-adrenal axis; however, the physiological link [lactational corticosterone (CORT) transfer] between mother and offspring during postnatal development constrains the ability to determine the direct effects of such stressors on subsequent physiology and behavior. Here we present a novel model using an avian species, the zebra finch (Taeniopygia guttata), in which maternal hormonal transfer during postnatal development is likely to be absent. Postnatal exposure of chicks to the stress hormone CORT was manipulated for a 16-d period up until nutritional independence (28 d), and the long-term effects on the physiological response to stress determined. CORT doses were scaled to mimic the physiological response of juvenile birds to a capture-handling-restraint protocol. CORT-fed birds showed exaggerated and prolonged responses to acute stress at 60 d of age. Our results clearly demonstrate that postnatal stress has significant long-term effects on the physiological stress response in birds and provides a potential mechanism underlying long-term behavioural responses to developmental conditions. This study represents the first direct evidence for postnatal glucocorticoid programming of the stress response using this novel model for postnatal stress. This model therefore provides an important tool with which to investigate the role of glucocorticoids in shaping adult phenotypes.
发育过程中所经历的环境条件如何塑造成年后的表型，以及这种诱导变化在多大程度上具有适应性，这一问题在国际上引起了越来越多的关注。下丘脑-垂体-肾上腺轴是一个在发育过程中将个体与环境变化联系起来的生理系统。哺乳动物研究已将出生后早期应激与下丘脑-垂体-肾上腺轴的后期变化联系起来；然而，出生后发育过程中母体与后代之间的生理联系[哺乳期皮质酮（CORT）传递]限制了确定此类应激源对后续生理和行为直接影响的能力。在此，我们提出了一种使用鸟类物种斑胸草雀（Taeniopygia guttata）的新模型，在该模型中出生后发育过程中母体激素传递可能不存在。将雏鸟在出生后暴露于应激激素CORT中16天，直至营养独立（28天），并确定其对压力生理反应的长期影响。CORT剂量按比例调整以模拟幼鸟对捕捉-处理-束缚方案的生理反应。喂食CORT的鸟类在60日龄时对急性应激表现出夸张和延长的反应。我们的结果清楚地表明，出生后应激对鸟类的生理应激反应具有显著的长期影响，并为发育条件的长期行为反应提供了潜在机制。这项研究代表了使用这种出生后应激新模型进行出生后糖皮质激素对应激反应编程的首个直接证据。因此，该模型提供了一个重要工具，用以研究糖皮质激素在塑造成年表型中的作用。
