DEVELOPMENT OF PEPTIDERGIC PROJECTIONS FROM ARCUATE NUCLEUS OF HYPOTHALAMUS

下丘脑弓状核肽能投射的发育

• 批准号: 6597591
• 负责人: RICHARD B SIMERLY
• 金额: $ 17.24万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-03 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6597591
• 关键词: adrenocorticotropic hormone; appetite regulatory center; central neural pathway /tract; developmental neurobiology; endogenous opioid; endorphins; fluorescent dye /probe; hormone receptor; hormone regulation /control mechanism; hypothalamus; immunocytochemistry; in situ hybridization; laboratory mouse; melanocyte stimulating hormone; mixed tissue /cell culture; neuroendocrine system; neuronal transport; neuroregulation; opioid receptor; paraventricular nucleus

The long range goal of this line of research is to clarify the organization and development of peptidergic neural pathways from the arcuate nucleus of the hypothalamus (ARH) to hypothalamic regions known to mediate neuroendocrine regulation of mammalian homeostasis have evolved to integrate the neural system that control gonadotropin secretion and ingestive behavior. The ARH represents a key neuroanatomical interface between such systems, and its importance for gonadotropin secretion and feeding behavior is well documented. However, the detailed neurological mechanisms underlying these essential functions remain unclear, and little is known about the nuclei of the hypothalamus play key roles in mediating gonadotropin section and feeding behavior and share strong connections with the ARH, as well as with the paraventricular nucleus of the hypothalamus (PVH), which may represent the final common pathway for hypothalamic regulation of energy balance. In addition, each of the these nuclei express receptors for melanocortin and opiatergic peptides, which have been implicated in the regulation of both ingestive behavior and neural development. The overall hypothesis of this proposal is that melanocortin and opiatergic peptides are expressed in projections from the RH to the AVPV, PVH, and DMH, and that these peptides directly influence the development of connections between these nuclei. Anterograde axonal transport and histochemical methods will be used, together with both in vivo and in vitro model systems, to address the following specific aims. Specific Aim 1. Anterograde axonal transport of the tracer PHA-L will be used together with immunohistochemistry to demonstrate the presence of beta- endorphin (betaEND) and alpha melanocyte stimulating hormone (alphaMSH) in projections from the ARH to the AVPV and DMH in adult mice (C57Bl/6J). Specific Aim 2. The fluorescent racer DiI will be used to demonstrate the development of projects from the ARH to the AVPV, PVH and DMH in neonatal male and female mice. Specific Im 3. In situ hybridization will be used to correlate the expression of MC4 and mu or delta opiate receptors in the AVPV, PVH and DMH of neonatal animals with the arrival of inputs to these nuclei from the ARH. Specific Aim 4. DiI will also be used to study the development of neural projections from the RH to the AVPV, PVH and DMH in transgenic mice that lack functional receptors for beta-endorphin or MC4. Specific Aim 5. Axonal transport and immunohistochemistry in transgenic mice that lack functional receptors for beta-endorphin and alpha MSH containing projections from the ARH to the AVPV, PVH or DMH in organotypic hypothalamic explant co-cultures maintained in vitro under defined conditions. These studies will provide novel insights into cellular mechanisms underling the development of hypothalamic neural systems regulating homeostasis, and may also provide clues about the ontogeny of neurological defects related to infertility and obesity.

这一系列研究的长期目标是阐明从下丘脑弓状核(ARH)到下丘脑的肽能神经通路的组织和发展。已知的调节哺乳动物神经内分泌调节的区域已经进化到整合控制促性腺激素分泌和摄食行为的神经系统。ARH代表了这类系统之间的关键神经解剖学接口，它对促性腺激素分泌和摄食行为的重要性已经得到了很好的证明。然而，这些基本功能的具体神经机制尚不清楚，下丘脑核团在调节促性腺激素分泌和摄食行为中发挥关键作用，并与ARH以及下丘脑室旁核(PVH)有着密切的联系，这可能是下丘脑能量平衡调节的最终共同途径。此外，这些核团中的每一个都表达黑素皮质素和阿片肽的受体，这两种受体都参与了对摄食行为和神经发育的调节。这一设想的总体假设是，黑素皮质素和阿片肽在RH向AVPV、PVH和DMH的投射中表达，这些肽直接影响这些核团之间联系的发展。将使用顺行轴突运输和组织化学方法，以及体内和体外模型系统，以解决以下特定目标。具体目的1.用顺行轴突运输示踪剂PHA-L结合免疫组织化学方法，观察成年小鼠(C57BL/6J)ARH向AVPV和DMH的投射中存在β-内啡肽(β-END)和α-黑素细胞刺激素(α-MSH)。具体目的2.荧光示踪剂DiI将用于演示新生雄性和雌性小鼠从ARH到AVPV、PVH和DMH的投射的发展。用原位杂交法研究新生动物AVPV、PVH和DMH中MC4和Mu或Delta阿片受体的表达与ARH传入这些核团的关系。具体目的4.DII还将用于研究缺乏β-内啡肽或MC4功能性受体的转基因小鼠从RH到AVPV、PVH和DMH的神经投射的发育。具体目的5.缺乏β-内啡肽和α-MSH功能性受体的转基因小鼠的轴突运输和免疫组织化学在体外维持的器官型下丘脑外植体共培养中包含从ARH到AVPV、PVH或DMH的投射。这些研究将为下丘脑调节内稳态的神经系统发育的细胞机制提供新的见解，并可能为与不孕症和肥胖症相关的神经缺陷的个体发生提供线索。