Hiroi Ryoko, Neumaier John F
Department of Psychology, University of Washington, Seattle, WA 98195, USA.
Behav Brain Res. 2006 Jan 6;166(1):93-100. doi: 10.1016/j.bbr.2005.07.021. Epub 2005 Sep 9.
The ovarian steroids, estrogen (E) and progesterone (P), have been shown to affect anxiety and fear in humans and animals, although with inconsistent results. These ambiguous findings may be due to differential actions of ovarian steroids on anxiety versus fear. To investigate such a role, we used the open field test (OFT) and fear-potentiated startle (FPS). We examined these behaviors between cycling female rats in proestrus (high E and rising P) or diestrus (low E and P), as well as between ovariectomized rats treated for 2 weeks with placebo, E, or E plus P (OVX, OVX/E, OVX/EP, respectively). We found no differences in anxiety-like or fear behaviors in OFT or FPS between proestrus and diestrus rats, perhaps due to the opposing effects of E and P. In contrast, we found that the OVX/E rats spent more time in the center of the OFT compared to the OVX and OVX/EP rats with no difference in overall activity level, suggesting that E reduced anxiety and this was opposed by P. With FPS, the OVX/E rats showed increased startle in the first third of the testing session, followed by a rapid decline in startle magnitude in subsequent trials. The addition of P to E treatment counteracted this effect. In conclusion, E may have differential effects on specific components of anxiety and fear; E may decrease anxiety in a naturalistic environment, but intensify both fear learning and extinction processes. P antagonizes these E effects on anxiety and fear.
卵巢甾体激素，雌激素（E）和孕激素（P），已被证明会影响人类和动物的焦虑和恐惧，尽管结果并不一致。这些不明确的发现可能是由于卵巢甾体激素对焦虑和恐惧的作用不同。为了研究这种作用，我们使用了旷场试验（OFT）和恐惧增强惊吓（FPS）。我们检查了处于动情前期（高E和上升的P）或动情间期（低E和P）的发情周期雌性大鼠之间，以及分别用安慰剂、E或E加P处理2周的去卵巢大鼠（分别为OVX、OVX/E、OVX/EP）之间的这些行为。我们发现动情前期和动情间期大鼠在OFT或FPS中的焦虑样或恐惧行为没有差异，这可能是由于E和P的相反作用。相比之下，我们发现OVX/E大鼠与OVX和OVX/EP大鼠相比，在OFT中心区域停留的时间更长，而总体活动水平没有差异，这表明E减轻了焦虑，而P则起到了相反的作用。在FPS试验中，OVX/E大鼠在测试的前三分之一时间内惊吓反应增强，随后在后续试验中惊吓幅度迅速下降。在E治疗中添加P可抵消这种效应。总之，E可能对焦虑和恐惧的特定成分有不同的影响；E可能在自然环境中降低焦虑，但会增强恐惧学习和消退过程。P拮抗E对焦虑和恐惧的这些作用。
