Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York 10021; Bekesy Laboratory of Neurobiology, University of Hawaii, Honolulu, Hawaii 96822; and Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
Mol Cell Neurosci. 1993 Dec;4(6):543-8. doi: 10.1006/mcne.1993.1067.
The housing of male and female rats in a visible burrow system in which a dominance hierarchy is established and interactions between animals can be monitored provides an effective method by which the behavioral and neuroendocrine effects of social stress can be examined. In this social system, subordinate male rats exhibit plasma corticosterone levels that appear to be chronically elevated relative to the dominant rats in the colonies and compared to singly housed controls. Previous studies have indicated that in the hippocampus adrenal steroids negatively regulate the expression of the mRNAs encoding the glucocorticoid receptor (GR), the mineralocorticoid receptor (MR), and the growth-associated protein GAP-43, while the preproenkephalin (ppENK) mRNA is positively regulated by glucocorticoids. This study examined the effect of social stress and the resulting sustained increase in steroid levels in the subordinate animals on gene expression in the hippocampus. The results indicated that GR, MR, and GAP-43 mRNAs were decreased in subordinate rats relative to controls, in the CA1 region of the hippocampus, while ppENK mRNA was unaffected. No statistically significant differences in mRNA expression were observed in other hippocampal subfields. These findings suggest that the social stress encountered by the subordinate rats in this burrow environment elicits changes in hippocampal gene expression that are consistent with their regulation by adrenal steroids.
雄性和雌性大鼠的住房安置在一个可见的洞穴系统中，在这个系统中建立了优势等级制度，并且可以监测动物之间的相互作用，为研究社会压力对行为和神经内分泌的影响提供了有效的方法。在这种社会系统中，处于从属地位的雄性大鼠的血浆皮质酮水平似乎相对于群体中的优势大鼠和单独饲养的对照组大鼠长期升高。先前的研究表明，在海马体中，肾上腺类固醇负调节编码糖皮质激素受体 (GR)、盐皮质激素受体 (MR) 和生长相关蛋白 GAP-43 的 mRNA 的表达，而前原脑啡肽 (ppENK) mRNA 则受糖皮质激素的正调节。本研究检查了社会压力及其导致的从属动物类固醇水平持续升高对海马体基因表达的影响。结果表明，与对照组相比，从属大鼠海马体 CA1 区的 GR、MR 和 GAP-43 mRNA 减少，而 ppENK mRNA 不受影响。在其他海马体亚区未观察到 mRNA 表达的统计学显著差异。这些发现表明，从属大鼠在这种洞穴环境中遇到的社会压力引起了海马体基因表达的变化，这与它们受肾上腺类固醇的调节一致。
