BRAIN ANGIOTENSIN II RECEPTOR IN HYPERTENSION

高血压脑血管紧张素 II 受体

• 批准号: 2223046
• 负责人: KATHLEEN HELEN BERECEK
• 金额: $ 21.5万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2223046
• 关键词: angiotensin /renin /aldosterone hypertension; angiotensin II; antihypertensive agents; captopril; chemical binding; disease /disorder model; genetic models; hormone receptor; hormone regulation /control mechanism; hypothalamus; laboratory rat; neurochemistry; norepinephrine; tissue /cell culture; vascular smooth muscle

The long-term goals of this proposal are to study angiotensin II (AII) receptor regulation in primary neuronal enriched (PNC) and vascular smooth muscle cell (VSMC) cultures from SHR, WKY and Sprague-Dawley (SD) rats, to examine the effects of captopril and other converting enzyme inhibitors (CEI) on AII receptor regulation in these rats and to determine whether the anti-hypertensive effect of CEI in SHR is related to a down-regulation of brain AII receptors. We will utilize PNC and VSMC cultures from neonates to compare AII receptor regulation in SHR vs normotensive rats and to determine the effects of CEI on central and peripheral AII receptors. This project is divided into two specific aims. Specific Aim 1: To test the hypothesis that brain AII receptors are biochemically and functionally different in SHR vs normotensive rat strains and that brain AII receptors in SHR are regulated differently from those of WKY and SD rats. We will utilize radioligand binding techniques to characterize AII receptor number and affinity in PNC (hypothalamus/brain stem co-cultures) from SHR, WKY and SD pups and compare these to AII receptors in VSMC cultured from the same pups. Binding studies will be performed in intact cells and in membranes prepared from these cells. We will incubate cells with agents known to stimulate or decrease AII binding and determine whether there are differences in the responses of AII receptors in SHR vs WKY and in PNC vs VSMC cultures. We will functionally assess AII receptors in PNC and VSMC from SHR as compared to WKY and SD by monitoring 45 Ca2+ efflux, cytosolic [Ca2+], phosphoinositide turnover and AII stimulated release of vasopressin (VP). We propose that a major signal pathway mediating AII action in neuronal tissue is the inositol phosphate/Ca2+ pathway. Specific Aim 2: To test the hypothesis that administration of CEI to SHR is associated with down regulation of brain AII receptors. We will a) compare AII receptor number and affinity in PNC and VSMC from SHR, WKY and SD pups subjected to in utero treatment with CEI, b) we will determine the effects of short-term incubation of PNC and VSMC cultures with CEI of different chemical structures on AII binding kinetics. We will study the effects of these agents on the Kd and Bmax and the association and dissociation constants. We will also study the effect of these agents on AII receptor internalization and the coupling of the AII receptor to its second messenger. In order to determine the specificity of the effect of CEI on the AII receptor we will simultaneously monitor the effect of CEI on norepinephrine (NE) and VP binding. Results from the proposed study should increase our understanding of brain AII receptors and the regulation and how these receptors are altered in a genetic model of hypertension.

该提案的长期目标是研究血管紧张素II（AII） 原代神经元富集 (PNC) 和血管平滑肌中的受体调节 来自 SHR、WKY 和 Sprague-Dawley (SD) 大鼠的肌细胞 (VSMC) 培养物， 检查卡托普利和其他转化酶抑制剂的作用 (CEI) 对这些大鼠中 AII 受体的调节，并确定是否 CEI 在 SHR 中的抗高血压作用与下调 大脑AII受体。 我们将利用新生儿的 PNC 和 VSMC 培养物 比较 SHR 与正常血压大鼠的 AII 受体调节 确定 CEI 对中枢和外周 AII 受体的影响。 这 项目分为两个具体目标。 具体目标 1：测试 假设大脑 AII 受体在生化和功能上 SHR 与正常血压大鼠品系的差异以及大脑 AII 受体 SHR 中的调节与 WKY 和 SD 大鼠不同。 我们将 利用放射性配体结合技术来表征 AII 受体数量 和来自 SHR、WKY 和 PNC（下丘脑/脑干共培养物）的亲和力 SD 幼崽并将其与从相同培养物中培养的 VSMC 中的 AII 受体进行比较 小狗。 结合研究将在完整细胞和膜中进行 由这些细胞制备。 我们将用已知的试剂孵化细胞 刺激或减少 AII 结合并确定是否存在 SHR 与 WKY 以及 PNC 与 PNC 中 AII 受体反应的差异 VSMC 文化。 我们将对 PNC 和 VSMC 中的 AII 受体进行功能评估 通过监测 45 Ca2+ 流出、胞质，将 SHR 与 WKY 和 SD 进行比较 [Ca2+]、磷酸肌醇周转和 AII 刺激加压素释放 （副总裁）。 我们提出介导 AII 作用的主要信号通路 神经元组织是磷酸肌醇/Ca2+途径。 具体目标2： 检验 SHR 施用 CEI 与以下因素相关的假设： 大脑AII受体的下调。 我们将 a) 比较 AII 受体 来自 SHR、WKY 和 SD 幼崽的 PNC 和 VSMC 的数量和亲和力 使用 CEI 进行宫内治疗，b) 我们将确定短期治疗的效果 PNC 和 VSMC 培养物与不同化学物质的 CEI 一起孵育 AII 结合动力学的结构。 我们将研究这些的影响 试剂对 Kd 和 Bmax 以及结合和解离常数的影响。 我们还将研究这些药物对 AII 受体的影响 AII 受体的内化和与其第二个受体的偶联 信使。 为了确定 CEI 对 AII 受体，我们将同时监测 CEI 对 AII 受体的影响 去甲肾上腺素 (NE) 和 VP 结合。 拟议研究的结果应 增加我们对大脑 AII 受体及其调节和 这些受体在高血压遗传模型中如何改变。