Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA.
Sci Rep. 2019 Jul 18;9(1):10407. doi: 10.1038/s41598-019-46845-x.
Individual physiological variation may underlie individual differences in behaviour in response to stressors. This study tested the hypothesis that individual variation in dopamine and corticosteroid physiology in wild house sparrows (Passer domesticus, n = 15) would significantly predict behaviour and weight loss in response to a long-term stressor, captivity. We found that individuals that coped better with captivity (fewer anxiety-related behaviours, more time spent feeding, higher body mass) had lower baseline and higher stress-induced corticosteroid titres at capture. Birds with higher striatal D receptor binding (examined using positron emission tomography (PET) with C-raclopride 24 h post-capture) spent more time feeding in captivity, but weighed less, than birds with lower D receptor binding. In the subset of individuals imaged a second time, D receptor binding decreased in captivity in moulting birds, and larger D decreases were associated with increased anxiety behaviours 2 and 4 weeks post-capture. This suggests changes in dopaminergic systems could be one physiological mechanism underlying negative behavioural effects of chronic stress. Non-invasive technologies like PET have the potential to transform our understanding of links between individual variation in physiology and behaviour and elucidate which neuroendocrine phenotypes predict stress resilience, a question with important implications for both humans and wildlife.
个体生理差异可能是个体对压力源反应行为差异的基础。本研究检验了这样一个假设，即在野外家麻雀（Passer domesticus，n=15）中多巴胺和皮质甾醇生理学的个体差异将显著预测对长期压力源——囚禁的行为和体重减轻的反应。我们发现，那些在囚禁中应对能力更好的个体（焦虑相关行为较少，进食时间更多，体重更高）在捕获时基线皮质甾醇水平较低，应激诱导的皮质甾醇水平较高。在捕获后 24 小时使用 C-raclopride 进行正电子发射断层扫描（PET）检查时，纹状体 D 受体结合较高的鸟类在囚禁中花更多的时间进食，但体重比 D 受体结合较低的鸟类低。在对部分个体进行第二次成像的亚组中，在换羽的鸟类中，D 受体结合在囚禁中减少，并且 D 减少越大，与捕获后 2 周和 4 周时焦虑行为增加相关。这表明多巴胺能系统的变化可能是慢性应激对负面行为影响的一种生理机制。像 PET 这样的非侵入性技术有可能改变我们对个体生理学和行为差异之间联系的理解，并阐明哪些神经内分泌表型可以预测应激弹性，这对于人类和野生动物都具有重要意义。
