Department of Biology, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA; Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA; Department of Biology, University of South Alabama, 5871 USA Dr. N. Room 124, Mobile, AL 36688, USA; Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, Scotland, UK; The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, Scotland, UK.
Gen Comp Endocrinol. 2021 Mar 1;303:113701. doi: 10.1016/j.ygcen.2020.113701. Epub 2020 Dec 24.
Capture-restraint is often used to investigate the acute hypothalamic-pituitary-adrenal axis (HPA) response to stress in wild and captive animals through the production of glucocorticoids. Although this approach is useful for understanding changes in glucocorticoids, it overlooks potential changes in the complex regulatory systems associated with the glucocorticoid response, including genomic receptors, steroid metabolizing enzymes, carrier proteins, and downstream target proteins (e.g. gonadotropin-inhibitory hormone; GnIH). The present study in captive male white-crowned sparrows (Zonotrichia leucophrys) tests the hypothesis that corticosteroid receptors (mineralocorticoid - MR and glucocorticoid - GR), 11β-hydroxysteroid dehydrogenase 1 (11βHSD1) and 2 (11βHSD2), corticosteroid binding globulin (CBG), and GnIH undergo rapid changes in expression to mediate the glucocorticoid response to acute stress. To determine dynamic changes in gene mRNA expression in the hippocampus, hypothalamus, pituitary gland, and liver, birds were sampled within 3 min of entering the room and after 10, 30, and 60 min of capture restraint stress in a cloth bag. Restraint stress handling increased CBG and decreased GnIH mRNA expression in the liver and hypothalamus, respectively. MR, GR, 11βHSD1, and 11βHSD2 mRNA expression in the brain, pituitary gland, and liver did not change. No correlations were found between gene expression and baseline or stress-induced plasma corticosterone levels. No rapid changes of MR, GR, 11βHSD1, and 11βHSD2 mRNA expression during a standardized acute restraint protocol suggests that tissue level sensitivity may remain constant during acute stressors. However, the observed rise in CBG mRNA expression could act to facilitate transport to target tissues or buffer the rise in circulating glucocorticoids. Further studies on tissue specific sensitivity are warranted.
束缚应激通常用于通过产生糖皮质激素来研究野生和圈养动物的急性下丘脑-垂体-肾上腺轴（HPA）对应激的反应。尽管这种方法有助于了解糖皮质激素的变化，但它忽略了与糖皮质激素反应相关的复杂调节系统的潜在变化，包括基因组受体、类固醇代谢酶、载体蛋白和下游靶蛋白（例如促性腺激素抑制激素；GnIH）。本研究以圈养雄性白头鹀（Zonotrichia leucophrys）为研究对象，检验了皮质甾醇受体（盐皮质激素 - MR 和糖皮质激素 - GR）、11β-羟类固醇脱氢酶 1（11βHSD1）和 2（11βHSD2）、皮质甾醇结合球蛋白（CBG）和 GnIH 是否会迅速改变表达，以介导糖皮质激素对急性应激的反应这一假设。为了确定海马体、下丘脑、垂体和肝脏中基因 mRNA 表达的动态变化，在进入房间后 3 分钟内和在布袋中进行 10、30 和 60 分钟的捕获应激处理后，对鸟类进行采样。束缚应激处理分别增加了肝脏和下丘脑的 CBG 和 GnIH mRNA 表达。大脑、垂体和肝脏中的 MR、GR、11βHSD1 和 11βHSD2 mRNA 表达没有变化。基因表达与基础或应激诱导的血浆皮质酮水平之间没有相关性。在标准化急性束缚方案中，未发现 MR、GR、11βHSD1 和 11βHSD2 mRNA 表达的快速变化，这表明组织水平的敏感性在急性应激期间可能保持不变。然而，观察到的 CBG mRNA 表达增加可能有助于向靶组织转运或缓冲循环中糖皮质激素的增加。需要进一步研究组织特异性敏感性。
