Integration of Stress and Reproductive Axes by Dopamine

描述（由申请人提供）：我们的总体目标是确定应激反应系统和生殖系统如何相互作用。这一建议是基于我们的观察，多巴胺神经元在内侧不动带（MZI）对循环肾上腺类固醇水平的变化是敏感的。众所周知，这些神经元调节生殖和摄食行为，但以前没有涉及到应激反应。然而，这些神经元被认为投射到下丘脑室旁核（PVN）的促肾上腺皮质激素释放激素（CRH）神经元，从而调节下丘脑-垂体-肾上腺（HPA）轴的活性，这种活性在应激时增加。我们假设MZI多巴胺神经元的活动导致PVN释放多巴胺，同时刺激生殖行为并抑制应激反应。此外，我们假设这种活动对糖皮质激素水平敏感，在压力下糖皮质激素水平会增加。在具体目标一中，我们将确定MZI内的多巴胺系统转录本是否受糖皮质激素的调节，如果是，是哪一种。这将通过结合激光捕获显微镜（LCM）分离MZI神经元和定量实时PCR （qRT-PCR）测量肾上腺切除大鼠多巴胺转录水平来实现。在具体目标二中，我们将确定哪些多巴胺受体在PVN中表达，特别是哪些（如果有的话）在CRH神经元上表达。这也将通过PVN神经元的LCM与qRT-PCR结合，然后进行双标记原位杂交来实现。在具体目标三中，我们将向PVN注射多巴胺激动剂，并确定这种操作对HPA激活标记物的影响，即血清促肾上腺皮质激素和皮质酮的增加。在这些研究中，大鼠将被插管，以便在处理或抑制压力之前注射到PVN。这些研究对人类健康很重要，因为它们将有助于阐明多巴胺活性在PVN中的功能以及调节这种活性的因素。这是相关的，因为一些临床使用的治疗精神病、性功能障碍和帕金森病等各种疾病的药物会操纵大脑多巴胺，而这种操纵对压力和HPA活动的影响尚不清楚。

DESCRIPTION (provided by applicant): Our overall goal is to determine how the stress response system and the reproductive system interact. This proposal is based on our observation that dopamine neurons in the medial zona incerta (MZI) are sensitive to variations in circulating adrenal steroid levels. These neurons are known to regulate reproductive and feeding behavior but have not previously been implicated in the stress response. However, these neurons are believed to project to corticotropin releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) and are thus in a position to regulate hypothalamic-pituitary-adrenal (HPA) axis activity, which is increased during stress. We hypothesize that activity of MZI dopamine neurons leads to dopamine release in the PVN and that this simultaneously stimulates reproductive behavior and inhibits the stress response. Furthermore, we hypothesize that this activity is sensitive to glucocorticoid levels, which increase during stress. In specific aim one we will determine if dopamine system transcripts within the MZI are regulated by glucocorticoids and, if so, which ones. This will be accomplished by combining laser- capture microscopy (LCM), to isolate MZI neurons, with quantitative real-time PCR (qRT-PCR) to measure dopamine transcript levels in adrenalectomized rats. In specific aim two we will determine which dopamine receptors are expressed in the PVN and specifically, which, if any, are expressed on CRH neurons. This will also be accomplished by combining LCM of PVN neurons with qRT-PCR followed by double-labeled in situ hybridization. In specific aim three we will inject a dopamine agonist into the PVN and determine the effect of this manipulation on markers of HPA activation, namely, increases in serum adrenocorticotropin hormone and corticosterone. For these studies rats will be cannulated to allow injection into the PVN just prior to either handling or restraint stress. The studies are important to human health because they will help elucidate the function of dopamine activity in the PVN and the factors that regulate this activity. This is relevant because several clinically used drugs that treat conditions as varied as psychosis, sexual dysfunction and Parkinson's disease manipulate brain dopamine and the consequences of this manipulation on stress and HPA activity is not understood.