BACKGROUND Predatory stress as a psychological stressor can elicit the activation of the hypothalamic-pituitary-adrenal (HPA) axis, which is involved in the dialogue of the neuroimmunoendocrine network. The brain has been proven to regulate the activity of the HPA axis by way of lateralization. In the present study, we probed the pivotal elements of the HPA circuitry including CRH, GR and a multifunctional cytokine in behavior-lateralized mice to determine their changes when the animals were subjected to predator exposure. METHODS Behavior-lateralized mice were classified into left-pawed and right-pawed mice through a paw-preference test. Thereafter, mice in the acute stress group received a single 60-min cat exposure, and mice in the chronic group received daily 60-min cat exposure for 14 consecutive days. The plasma CS and TNF-α were determined by ELISA, the hypothalamic CRH mRNA and hippocampal GR mRNA were detected by real-time PCR, and the hippocampal GR protein was detected by western blot analysis. RESULTS The results revealed that the levels of plasma CS were significantly elevated after chronic predatory exposure in both right-pawed and left-pawed mice; the right-pawed mice exhibited a higher plasma CS level than the left-pawed mice. Similarly, the acute or chronic cat exposure could induce the release of plasma TNF-α, and the left-pawed mice tended to show a higher level after the acute stress. Chronic stress significantly upregulated the expression of hypothalamic CRH mRNA in both left-pawed and right-pawed mice. Normally, the left-pawed mice exhibited a higher GR expression in the hippocampus than the right-pawed mice. After the cat exposure, the expression of GR in both left-pawed and right-pawed mice was revealed to be greatly downregulated. CONCLUSION Our findings indicate that predatory stress can invoke a differential response of stressful elements in behavior-lateralized mice. Some of these responses shaped by behavioral lateralization might be helpful for facilitating adaption to various stimuli.

中文翻译：

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行为偏侧小鼠中应激元素对掠食性暴露的差异反应。

背景技术作为心理应激源的掠夺性应激可引起下丘脑-垂体-肾上腺（HPA）轴的激活，该轴参与神经免疫内分泌网络的对话。事实证明，大脑可以通过侧化作用来调节HPA轴的活动。在本研究中，我们在行为偏向小鼠中探查了HPA电路的关键要素，包括CRH，GR和多功能细胞因子，以确定当动物遭受捕食者暴露时它们的变化。方法行为偏侧小鼠通过爪偏试验分为左爪和右爪小鼠。此后，急性应激组的小鼠接受一次60分钟的猫暴露，而慢性组的小鼠则连续14天每天接受60分钟的猫暴露。ELISA法测定血浆CS和TNF-α，实时PCR检测下丘脑CRH mRNA和海马GR mRNA，Western blot法检测海马GR蛋白。结果结果表明，在长期掠食性暴露后，右爪和左爪小鼠的血浆CS水平均显着升高。右爪小鼠的血浆CS水平高于左爪小鼠。同样，急性或慢性猫暴露也会诱导血浆TNF-α的释放，并且在急性应激后，左爪小鼠倾向于表现出更高的水平。慢性应激显着上调了左爪和右爪小鼠下丘脑CRH mRNA的表达。正常情况下，左爪小鼠在海马中的GR表达高于右爪小鼠。在猫暴露后，揭示了左爪和右爪小鼠中GR的表达均被大大下调。结论我们的发现表明，掠夺性应激可以引起行为偏化小鼠中应激元素的差异反应。这些由行为偏侧化形成的反应中的某些反应可能有助于促进适应各种刺激。