Decreases in Mineralocorticoid but not Glucocorticoid Receptor mRNA Expression During the Short Arctic Breeding Season in Free-Living Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii)
Decreases in Mineralocorticoid but not Glucocorticoid Receptor mRNA Expression During the Short Arctic Breeding Season in Free-Living Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii)
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DOI：
10.1111/jne.12237
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发表时间：
2015-01-01
影响因子：
3.2
通讯作者：
Meddle, S. L.
中科院分区：
文献类型：
--
作者：
Krause, J. S.;McGuigan, M. A.;Meddle, S. L.
脊椎动物的急性应激反应是一套高度适应性的生理和行为机制，可促进面对环境有害刺激时的生存。生理和行为的兼性变化是通过糖皮质激素（皮质酮、皮质醇）循环水平的变化及其随后与高亲和力盐皮质激素受体（MR）或低亲和力糖皮质激素受体（GR）的结合来介导的。自由生活的雄性野生甘贝尔白冠麻雀（Zonotrichia leucophrys gambelii）的应激反应表现出年度波动，并且在从亲代前到亲代阶段的过渡期间显着减弱。我们利用原位杂交研究了这种应激反应的快速减少是否是通过大脑中 MR 和 GR mRNA 表达的变化来介导的。研究发现，当雄鸟成为亲代后，海马体中 MR mRNA 的表达显着降低。此时室旁核（PVN）或视前区（POA）中GR mRNA表达没有观察到变化。皮质酮的初始捕获水平与 GR 或 MR mRNA 表达之间没有发现显着相关性。在为原位杂交收集的鸟类中，亲代前和亲代之间的皮质酮基础水平没有发现差异。应激反应数据显示，基线时没有差异，但随着鸟类成为父母，皮质酮的峰值水平有所降低。这些数据表明，MR 表达的变化可能对于调节应激反应或行为应激敏感性以促进父母照顾和投资很重要。
The acute stress response in vertebrates is a highly adaptive suite of physiological and behavioural mechanisms that promote survival in the face of deleterious stimuli from the environment. Facultative changes of physiology and behaviour are mediated through changes in circulating levels of glucocorticoids (corticosterone, cortisol) and their subsequent binding to the high-affinity mineralocorticoid receptor (MR) or the low-affinity glucocorticoid receptor (GR). Free-living male wild Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) display annual fluctuations in the stress response with marked attenuation during the transition from the pre-parental to the parental stage. We investigated whether this rapid reduction in the stress response is mediated through changes in MR and GR mRNA expression in the brain using in situ hybridisation. MR mRNA expression was found to be significantly lower in the hippocampus as the male birds became parental. No changes were observed in GR mRNA expression in the paraventricular nucleus (PVN) or preoptic area (POA) at this time. No significant correlations were found between initial capture levels of corticosterone and GR or MR mRNA expression. No differences were found in basal levels of corticosterone between pre-parental and parental in birds collected for in situ hybridisation. Stress response data revealed no difference at baseline but reductions in peak levels of corticosterone as birds became parental. These data suggest that changes in MR expression may be important for the regulation of the stress response or behavioural stress sensitivity with respect to promoting parental care and investment.