EDRF AND THE JUXTAGLOMERULAR APPARATUS

肾小球旁结构(JGA)是肾小球内的一种解剖结构。 哺乳动物的肾脏，它连接着肾小球血管极和肾脏 远端小管的黄斑致密细胞。有证据表明这一点 结构对肾素分泌和肾脏血液的调节很重要 流。这项研究的目的是了解 构成肾小球旁器的细胞类型。以前的工作 已经证实致密黄斑的生理性增加 浓度可引起局部肾小球前血管收缩和抑制 肾素分泌。 建议的研究集中在EDRF或一氧化氮在信号中的作用 肾小球旁结构的传递。最近的证据表明 确定存在一种结构性的钙激活的一氧化氮合酶 在致密黄斑或与动物的状态，和那个黄斑 Densa NO可能影响肾素分泌和/或肾小球血管 语气。在特定的目标1中，我们建议评估异构体的表达 一氧化氮合酶和可溶性鸟苷酸环化酶在JGA的 蛋白质水平。我们建议用来研究它们的细胞定位 原位杂交和免疫组织化学技术及其应用 用定量聚合酶链式反应进行盐分平衡调节。《特定目标2》 3.我们提出了一系列关于NO对血管紧张素转换酶的影响的功能研究 肾素和血管张力。在具体目标4中，我们建议直接 测量致密黄斑无代次。拟议的研究使用 完整的动物研究、体外分离系统和细胞研究的结合 培养方法。 这些研究的长期目标是更好地定义基础细胞 局部控制肾素分泌的机制，肾素 合成和肾小球血管紧张度。我们预计，由此产生的 洞察力将有助于理解以下疾病状态 这些调节事件可能是紊乱的，例如充血的心脏 衰竭、某些形式的高血压和进行性肾功能不全。

The juxtaglomerular apparatus (JGA) is an anatomic structure in the mammalian kidney which links the glomerular vascular pole with the macular densa cells of the distal tubule. There is evidence that this structure is important for regulation of renin secretion and renal blood flow. Research is aimed at understanding the interactions between the cell types which make up the juxtaglomerular apparatus. Previous work has established that physiological increases in macula densa NaC1 concentration produce local preglomerular vasoconstriction and inhibition of renin secretion. The proposed studies focus on the role of EDRF or nitric oxide in signal transmission in the juxtaglomerular apparatus. Recent evidence has established that a constitutive, calcium-activated NO synthase is present in the macula densa or with the state of the animal, and that macula densa NO may act to influence renin secretion and/or glomerular vascular tone. In specific aim 1, we propose to assess expression of the isoforms of NOS and the soluble guanylyl cyclases in the JGA at the mRNA and protein level. We propose to examine their cellular localization using in situ hybridization and immunohistochemical techniques and their regulation by salt balance using quantitative PCR. In specific aims 2 and 3, we propose a series of functional studies on the effects of NO on renin and vascular tone. In specific aim 4, we propose direct measurements of macula densa NO generation. Proposed studies use a combination of intact animal studies, isolated in vitro systems, and cell culture methods. The long term aim of these studies is to better define the basic cellular mechanisms that underlie local control of renin secretion, renin synthesis and glomerular vascular tone. We expect that the resultant insights will contribute to the understanding of disease states in which these regulatory events may be disordered, such as congestive heart failure, some forms of hypertension and progressive renal insufficiency.