Jasnow Aaron M, Schulkin Jay, Pfaff Donald W
Laboratory of Neurobiology and Behavior, Box 275, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Horm Behav. 2006 Feb;49(2):197-205. doi: 10.1016/j.yhbeh.2005.06.005. Epub 2005 Aug 3.
Estrogens exert important actions on fear and anxiety-like behavior both in humans and non-human animals. Currently, the mechanisms underlying estrogenic modulation of fear are not known. However, evidence suggests that estrogens may exert their influence on fear within the amygdala. The purpose of the present study was to examine effects of estrogen on fear conditioning. Specifically, the present study examined whether long-term estrogen treatment in ovariectomized female mice via Silastic capsule implantation would facilitate both contextual and cued fear conditioning. In a separate set of experiments, we then examined whether estrogen treatment in ovariectomized female mice would modulate corticotropin-releasing hormone (CRH) gene expression within the amygdala. Long-term estrogen treatment facilitated both contextual and cued fear. Ovariectomized mice treated with estrogen froze significantly more to a context as well as to a discrete auditory cue. In addition, estrogen treatment significantly increased CRH mRNA expression within the central nucleus of the amygdala as measured by in situ hybridization and quantitative PCR. These data raise the possibility that estrogens could influence fear responses in females through their actions in the amygdala.
雌激素对人类和非人类动物的恐惧及焦虑样行为均有重要作用。目前，雌激素调节恐惧的潜在机制尚不清楚。然而，有证据表明雌激素可能在杏仁核内对恐惧产生影响。本研究的目的是检验雌激素对恐惧条件反射的作用。具体而言，本研究考察了通过硅橡胶胶囊植入对去卵巢雌性小鼠进行长期雌激素处理是否会促进情境性和线索性恐惧条件反射。在另一组实验中，我们接着考察了对去卵巢雌性小鼠进行雌激素处理是否会调节杏仁核内促肾上腺皮质激素释放激素（CRH）的基因表达。长期雌激素处理促进了情境性和线索性恐惧。用雌激素处理的去卵巢小鼠在面对情境以及离散听觉线索时显著增加了僵立行为。此外，通过原位杂交和定量PCR检测发现，雌激素处理显著增加了杏仁核中央核内CRH mRNA的表达。这些数据提示，雌激素可能通过其在杏仁核中的作用影响雌性动物的恐惧反应。
