DHEA--A NEUROSTEROID MODULATING AGGRESSION

在人类和其他哺乳动物的大脑中合成的神经类固醇正在研究用于一系列人类健康状况（例如，焦虑、记忆、免疫功能、与衰老相关的问题）。 这些化合物之一，脱氢表雄酮（DHEA），是一个强大的抑制剂的攻击小鼠模型时，给予十五天，并可能是有用的管理不当的人类侵略。 虽然已经描述了DHEA的生物合成和代谢，但是关于这种抗攻击作用的机制存在显著的差距。 我们知道，15天的DHEA治疗降低了全脑硫酸双烯醇酮（PREG-S）的水平，这是一种直接在膜水平起作用的GABAA受体拮抗剂，我们最近发现DHEA还上调了边缘系统中的雄激素受体（AR），表明了基因组效应。 这两种事件都有助于增强GABA活性，这是一种抑制性神经递质，可以减少攻击性。 因此，所提出的研究的主要目标将是鉴定和/或定量延长的DHEA治疗的代谢、膜水平和基因组效应，然后确定每种对这种神经类固醇的攻击抑制效应的贡献。 将进行实验以定位DHEA治疗导致PREG-S显著下降的特定脑区域，表征在DHEA暴露过程中发生的GABAA受体结合的区域变化，确定DHEA的雄激素代谢物对AR调节的影响，其可能与这种神经类固醇的抗攻击作用有关，最后，进行功能性生物行为和体内微输注研究，包括药理学操作，以开始定义潜在的神经调节机制。其结果应实现两个目标。 其中之一是DHEA抑制攻击的关键机制和作用部位将被定义，推进这种行为的神经生物学模型。 另一个是，随着与DHEA的抗侵袭作用相关的膜水平和基因组作用的表征，将建立与延长的神经类固醇治疗相关的“串扰”细胞信号传导系统。 这一发现将显着促进我们对DHEA作用机制的理解，这是考虑到拟议临床用途的一个重要考虑因素。

Neurosteroids, which are synthesized in the brains of humans and other mammals, are under investigation for use in a range of human health conditions (e.g., anxiety, memory, immune function, problems associated with aging). One of these compounds, dehydroepiandrosterone (DHEA), is a powerful inhibitor of aggression in murine models when given for fifteen days and potentially may be useful in the management of inappropriate human aggression. Although the biosynthesis and metabolism of DHEA have been described, a significant gap exists concerning the mechanism(s) of this anti-aggressive effect. We know that 15 days of DHEA treatment reduces whole brain levels of pregnenolone sulfate (PREG-S), a GABAA receptor antagonist that works directly at the membrane level, and we recently discovered that DHEA also up-regulates androgen receptor (AR) in the limbic system, demonstrating a genomic effect. Both events can contribute to enhanced GABA activity, an inhibitory neurotransmitter known to reduce aggression. The major goal of the proposed research, therefore, will be to identify and/or quantitate the metabolic, membrane level, and genomic effects of extended DHEA treatment and then determine the contributions of each to the aggression- inhibiting effect of this neurosteroid. Experiments will be undertaken to localize the specific brain regions where DHEA treatment causes a significant decline in PREG-S, characterize the regional changes in GABAA receptor binding that occur over the course of DHEA exposure, define effects of the androgenic metabolites of DHEA on AR regulation that may be linked to the anti-aggressive action of this neurosteroid and, finally, perform functional biobehavioral and in vivo microinfusion studies involving pharmacological manipulations to begin defining underlying neural regulatory mechanisms. The results should achieve two objectives. One is that critical mechanisms and sites of action for the inhibition of aggression by DHEA will be defined, advancing models of the neurobiology of this behavior. The other is that with the characterization of both membrane-level and genomic actions linked to the anti- aggressive effect of DHEA, a "cross-talk" cellular signaling system associated with extended neurosteroid treatment would be established. This finding would significantly advance our understanding of the mechanism of action of DHEA, an important consideration given proposed clinical uses.