Smulders Tom V
Centre for Behaviour & Evolution, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK.
Neurobiol Stress. 2021 Jun 10;15:100351. doi: 10.1016/j.ynstr.2021.100351. eCollection 2021 Nov.
The hypothalamo-pituitary-adrenal (HPA) axis is one of the major output systems of the vertebrate stress response. It controls the release of cortisol or corticosterone from the adrenal gland. These hormones regulate a range of processes throughout the brain and body, with the main function of mobilizing energy reserves to improve coping with a stressful situation. This axis is regulated in response to both physical (e.g., osmotic) and psychological (e.g., social) stressors. In mammals, the telencephalon plays an important role in the regulation of the HPA axis response in particular to psychological stressors, with the amygdala and part of prefrontal cortex stimulating the stress response, and the hippocampus and another part of prefrontal cortex inhibiting the response to return it to baseline. Birds also mount HPA axis responses to psychological stressors, but much less is known about the telencephalic areas that control this response. This review summarizes which telencephalic areas in birds are connected to the HPA axis and are known to respond to stressful situations. The conclusion is that the telencephalic control of the HPA axis is probably an ancient system that dates from before the split between sauropsid and synapsid reptiles, but more research is needed into the functional relationships between the brain areas reviewed in birds if we want to understand the level of this conservation.
下丘脑-垂体-肾上腺（HPA）轴是脊椎动物应激反应的主要输出系统之一。它控制肾上腺皮质醇或皮质酮的释放。这些激素调节大脑和身体的一系列过程，主要功能是调动能量储备以更好地应对压力情况。该轴会根据身体（如渗透压）和心理（如社交）应激源做出反应。在哺乳动物中，端脑在调节HPA轴对心理应激源的反应中起重要作用，杏仁核和部分前额叶皮层刺激应激反应，而海马体和另一部分前额叶皮层抑制反应使其恢复到基线水平。鸟类也会对心理应激源产生HPA轴反应，但对于控制这种反应的端脑区域了解较少。这篇综述总结了鸟类中哪些端脑区域与HPA轴相连且已知会对压力情况做出反应。结论是，端脑对HPA轴的控制可能是一个古老的系统，可追溯到蜥形纲和合弓纲爬行动物分化之前，但如果我们想了解这种保守程度，还需要对鸟类中所综述的脑区之间的功能关系进行更多研究。
