MECHANISMS REGULATING NUTRITIVE CEREBRAL BLOOD FLOW

调节营养血液流动对大脑来说是一种非同寻常的 提供满足基本氧化要求的底物的动态过程 中枢神经的底物，同时为代谢提供充血血流 活跃区域。脑血流调节的基本原理是 大脑微循环的自我调节能力。开始，开始 理解这一过程需要对蜂窝和 毛细血管前小动脉感知的分子机制 环境条件和启动适当的信号转导 激活或抑制微血管收缩的事件和顺畅 肌肉。定义旨在调节营养物质的体内平衡机制 在综合功能水平上满足脑血流量(CBF) 生理需求超出了任何一个实验室的范围。大卫博士 哈德将指导这一计划，并领导项目1。项目中的研究 1将重点介绍分子、细胞和信号转导。 在波动中调节营养性CBF的自动调节 动脉压。我们最近对细胞色素P450(P450)进行了测序 分离的毛细血管前小动脉肌内的omega羟基酶基因 编码催化20-HETE形成的酶的细胞 花生四烯酸(AA)。抑制20-HETE的形成取消了 激光多普勒血流的正常、近乎完美的自动调节 大鼠顶叶皮质动脉压升高。项目2 将由理查德·罗曼博士领导，并将定义互动 一氧化氮(NO)和P450之间产生20-HETE。在 营养CBF NO的调节似乎直接与血红素结合 部分抑制P450酶活性。罗曼博士提供了 令人信服的数据支持了cGMP独立机制的假设 NO的作用之一是抑制P450 4A omega-羟基酶的活性，并 阻断内源性20-HETE的产生，20-HETE是最有效的血管活性物质之一 特工身份尚未确定。项目3将由Raymond Koehler博士领导 (约翰霍普金斯大学医学院)，它定义了 功能性充血患者星形胶质细胞P450环氧合酶活性的研究 大脑。我们已经从星形胶质细胞中测序了一个P450 2C11基因，它对 一种产生扩张性环氧二十碳三烯酸(EETs)的蛋白质。 谷氨酸诱导EETs的释放，调节2C11基因的表达。 克勒博士和他在约翰·霍普金斯大学的合作者有必要 专门知识来定义生理意义的作用 星形胶质细胞来源的EETs在抑制压力依赖性兴奋中的作用 毛细血管前循环和介导性功能性充血。大的 多项最新技术的范围、共同主题和应用 技术需要两个医疗机构之间的项目倡议 威斯康星学院和约翰霍普金斯大学在这项研究中提出 申请。这是一次重新提交，并已进行了大量修改 沿着科学综述研究部分所建议的路线。

Regulation of nutritive blood flow the brain is an extraordinarily dynamic process providing substrate to meet essential oxidative substrate to the CNS, while providing hyperemic flow to metabolically active areas. Fundamental to brain blood flow regulation is the autoregulatory capacity of the cerebral microcirculation. To begin to understand this process requires a basic definition of the cellular and molecular mechanisms through which pre-capillary arterioles sense environmental conditions and initiate appropriate signal transduction events to activate or inhibit contraction of microvascular and smooth muscle. Defining homeostatic mechanisms designed to regulate nutritive cerebral blood flow (CBF) at an integrated functional level to meet physiologic demand is beyond the scope of any one laboratory. Dr. David Harder will Direct this Program, and lead Project 1. Studies in Project 1 will focus on the molecular, cellular and signal transduction mediating autoregulation of nutritive CBF in the face of a fluctuation arterial pressure. We have recently sequenced a cytochrome P450 (P450) omegahydroxylase gene within isolated pre-capillary arteriolar muscle cells which codes for an enzyme catalyzing formation of 20-HETE from arachidonic acid (AA). Inhibition of 20-HETE formation abolishes the normal, nearly perfect, autoregulation of laser-Doppler blood flow to elevation of arterial pressure in the rat parietal cortex. Project 2 will be lead by Dr. Richard Roman, and will define the interactions between nitric oxide (NO) and P450 generated 20-HETE formation. In the regulation of nutritive CBF NO appears to bind directly to the heme moiety of, and inhibit P450 enzyme activity. Dr. roman provides compelling data for the hypothesis that the cGMP independent mechanisms of action of NO is to inhibit P450 4A omega-hydroxylase activity and block endogenous production of 20-HETE one of the most potent vasoactive agents yet identified. Project 3 will be lead by Dr. Raymond Koehler (Johns Hopkins University School of Medicine) which defines the role of astrocytic P450 epoxygenase activity in functional hyperemia in the brain. We have sequenced a P450 2C11 cDNA from astrocytes which does for a protein generating dilatory epoxyeicositrienoic acids (EETs). Glutamate induces release of EETs and regulates 2C11 gene expression. Dr. Koehler and his collaborators at Johns Hopkins have the necessary expertise to define the physiological significance of the role of astrocyte derived EETs in dampening pressure-dependent activation of the pre-capillary circulation and mediating functional hyperemia. The large scope, common theme and application of multiple state-of-the-art techniques necessitates the programmatic initiative between the Medical College of Wisconsin and Johns Hopkins University proposed in this application. This is a resubmission and has been substantially revised along the line suggested by the scientific review study sections.