Wacker Douglas W, Schlinger Barney A, Wingfield John C
Graduate Program in Neurobiology and Behavior, Department of Biology, Box 351800, University of Washington, Seattle, WA 98195, USA.
Horm Behav. 2008 Jan;53(1):287-94. doi: 10.1016/j.yhbeh.2007.10.008. Epub 2007 Oct 24.
The male Song Sparrow, Melospiza melodia morphna, shows high levels of aggression in its non-breeding season, concomitant with basal levels of circulating testosterone (T) and estradiol (E(2)). However, administration of fadrozole, an aromatase inhibitor, decreases non-breeding aggression in the field. Circulating levels of dehydroepiandrosterone (DHEA), an androgen/estrogen precursor, correspond to the seasonal expression of aggression in this species, with high levels in the breeding and non-breeding seasons when aggression is also high, and lower levels during the molt when aggression is low. We test the hypothesis that circulating DHEA up-regulates non-breeding aggression via an aromatase-mediated mechanism. We also hypothesize that this up-regulation of aggression is partially mediated by changes in vasoactive intestinal polypeptide (VIP) in the lateral extent of the bed nucleus of the stria terminalis (BSTl) and lateral septum (LS). Birds were administered either DHEA, fadrozole, or both for 2 weeks and tested for aggression in a lab-based paradigm. As predicted, birds given DHEA were significantly more aggressive. However, fadrozole did not block this effect, and, when administered without DHEA, also led to increased aggression over controls. These results may be explained by the fact that the behaviors measured in field tests, which include more direct attack behaviors, may be under different hormonal regulation than the behaviors measured in the lab paradigm, which represent warning, or threat, behaviors. VIP immunoreactivity (VIP-ir) changed across multiple brain regions with this treatment regimen, most notably in the LSO/VFI subdivision of the lateral septum.
雄性歌带鹀（Melospiza melodia morphna）在非繁殖季节表现出高度攻击性，同时伴有循环睾酮（T）和雌二醇（E₂）的基础水平。然而，给予芳香化酶抑制剂法倔唑可降低野外非繁殖期的攻击性。脱氢表雄酮（DHEA）是一种雄激素/雌激素前体，其循环水平与该物种攻击性的季节性表达相对应，在繁殖和非繁殖季节水平较高，此时攻击性也较高，而在换羽期水平较低，此时攻击性较低。我们检验了循环DHEA通过芳香化酶介导的机制上调非繁殖期攻击性的假说。我们还假设这种攻击性的上调部分是由终纹床核外侧区（BSTl）和外侧隔（LS）中血管活性肠肽（VIP）的变化介导的。给鸟类连续2周给予DHEA、法倔唑或两者，并在基于实验室的范式中测试其攻击性。正如预测的那样，给予DHEA的鸟类攻击性明显更强。然而，法倔唑并未阻断这种效应，并且在未给予DHEA时给予法倔唑，与对照组相比也导致攻击性增加。这些结果可能是因为野外测试中测量的行为（包括更直接的攻击行为）可能受到与实验室范式中测量的行为（代表警告或威胁行为）不同的激素调节。VIP免疫反应性（VIP-ir）随着这种治疗方案在多个脑区发生变化，最显著的是在外侧隔的LSO/VFI亚区。
