Integration and independence of neuroendocrine mechanisms of behavior

描述（由申请人提供）：本提案中描述的研究的总体目标是表征个体之间和性别之间从基因/蛋白质到激素到行为的多个生物组织水平的神经内分泌行为机制的整合程度。这项拟议中的研究将探讨这些组织水平之间的共同变化，重点是攻击性和性类固醇激素。以前的研究提供了对类固醇作用的坚定理解，但对于这些组织水平如何在个体内相互作用，导致特定的行为结果，留下了很大的不确定性。特别是，令人惊讶的是，几乎没有人知道大脑中类固醇结合分子的表达是否预测了个体水平上的行为变化。同样不清楚的是，导致性别内行为个体差异的机制是否在性别之间共享，即男性和女性使用相似或不同机制产生外表相似行为的程度。拟议的研究物种是一种鸣禽，黑眼junco（Junco hyemalis），这是理想的，由于广泛的现有知识的睾丸激素（T）对个体之间和性别之间的行为变化的影响。该研究将采用实验和观察方法，通过量化类固醇敏感性神经靶点（雄激素受体，AR;雌激素受体，ER;和芳香酶，ARO，将T转化为雌二醇，E2）的蛋白质和mRNA，跨越多种行为相关的神经位点。总的来说，神经系统方法用于解决两个具体目标：（1）识别个体的攻击性程度、其循环T和E2水平以及其AR、ER和ARO的神经表达之间的共变模式。这一目标是通过分析自由生活的受试者的攻击性，并将其行为与循环激素水平和神经类固醇靶点的mRNA进行比较来实现的。(2)比较男性和女性是否使用类似的类固醇介导的攻击机制。这一目标是通过使用第一项研究的数据来对比男性和女性之间的目标行为关系来实现的。第二项研究更深入，使用免疫细胞化学来确定特定神经回路中的性别差异，其中一个类固醇靶点（ARO）介导了攻击性。通过在攻击试验后将ARO与立即早期基因产物Fos共定位来量化ARO介导的攻击。这项研究将解决行为神经内分泌学中一个重要的未知因素（个体差异），然后将这种新方法扩展到性别比较。通过填补这些关键的知识空白，这项研究将阐明行为的基本神经内分泌机制。因此，它将有助于为未来研究影响类固醇介导的健康问题的神经内分泌因素奠定基础，包括具有高水平暴力/攻击性的行为障碍倾向的性别和个体差异（例如ADHD，行为障碍等），或改善相关神经缺陷的治疗方法。 公共卫生相关性：通过确定在个体水平上显性攻击变异的遗传和细胞因素，并比较男性和女性之间的神经内分泌机制，这项研究填补了有关基本生物行为机制的未解决的知识空白。因此，这些研究奠定了基础，为未来的进展，个性化治疗和预防的一些类固醇介导的行为障碍，影响儿童和成人的所有年龄。同样，识别差异性促进男性和女性攻击的因素将增加对神经生物学和行为中基本性别差异的理解，并可应用于未来关于攻击倾向或男性和女性其他由性别介导的健康问题中已知性别差异的原因/治疗的工作。

DESCRIPTION (provided by applicant): The overarching goal of the research described in this proposal is to characterize the degree of integration of neuroendocrine mechanisms of behavior at multiple levels of biological organization, from gene/protein to hormone to behavior, among individuals and between sexes. The proposed research will probe co-variation among these levels of organization, with a focus on aggression and sex steroid hormones. Previous research provides a firm understanding of steroid action, but leaves significant uncertainty about how these levels of organization interact with one another within an individual, leading to a specific behavioral outcome. In particular, surprisingly little is known as to whether the expression of steroid hormone-binding molecules in the brain predicts variation in behavior at the level of individuals. Also not clear is whether the mechanisms that lead to individual variability in behavior within a sex are shared between the sexes, i.e. the degree to which males and females use similar or different mechanisms to produce outwardly similar behaviors. The proposed study species is a songbird, the dark-eyed junco (Junco hyemalis), which is ideal owing to extensive existing knowledge of the effects of testosterone (T) on behavioral variation among individuals and between sexes. The research will employ both experimental and observational approaches by quantifying both protein and mRNA for steroid-sensitive neural targets (androgen receptor, AR; estrogen receptor, ER; and the enzyme aromatase, ARO, which converts T to estradiol, E2) across a diversity of behaviorally relevant neural loci. Collectively, a neural systems approach is used to address two specific aims: (1) To identify patterns of co-variation between an individual's degree of aggressiveness, its level of circulating T and E2 and its neural expression of AR, ER and ARO. This aim is achieved by assaying aggression in free-living subjects and comparing their behavior to circulating hormone levels and to mRNA for neural steroid targets, using quantitative PCR. (2) To compare whether males and females use similar steroid-mediated mechanisms of aggression. This aim is achieved by using data from the first study to contrast target-behavior relationships between males and females. A second study dives deeper, using immunocytochemistry to identify sex differences in the specific neural circuitry in which one steroid target (ARO) mediates aggression. ARO-mediated aggression will be quantified by co- localizing ARO with the immediate early gene product Fos following an aggression trial. The proposed research will address a significant unknown in behavioral neuroendocrinology (individual variation), and then extend this novel approach to sex comparisons. By filling these key knowledge gaps, this research will illuminate fundamental neuroendocrine mechanisms of behavior. It will thus contribute to a foundation of basic knowledge needed for future research on neuroendocrine factors affecting steroid-mediated health issues, including sex and individual differences in the propensity for behavioral disorders with high levels of violence/ aggression (e.g. ADHD, conduct disorder, etc.), or improved treatments of related neural deficiencies. PUBLIC HEALTH RELEVANCE: By identifying the genetic and cellular factors that underlie variability in overt aggression at the individual level and comparing these neuroendocrine mechanisms between males and females, this research fills unresolved knowledge gaps about basic biobehavioral mechanisms. These studies thus lay the groundwork for future advances in the individualized treatment and prevention of a number of steroid-mediated behavioral disorders affecting children and adults of all ages. Likewise, the identification of factors that differentially promote aggression in males and females will increase understanding of fundamental sex differences in neurobiology and behavior, and could be applied to future work on the causes/treatment of known sex differences in aggressive tendencies or other hormone-mediated health issues in men and women.