Autonomic and Antihypertensive Actions of Neuronal CGRP/RAMP1 Receptors

神经元 CGRP/RAMP1 受体的自主神经和抗高血压作用

• 批准号: 8698301
• 负责人: MARK W CHAPLEAU
• 金额: --
• 依托单位: IOWA CITY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8698301
• 关键词: Adenoviruses; Afferent Neurons; Aging; Angiotensin II; Angiotensin II Receptor; Animals; Antihypertensive Agents; Antioxidants; Anxiety; Arrhythmia; Arteries; Attenuated; Baroreflex; Binding; Blood Pressure; Blood Vessels; Brain; Brain Stem; Brain region; Buffers; Calcitonin Gene-Related Peptide; Calcitonin-Gene Related Peptide Receptor; Cardiovascular system; Cell Nucleus; Conscious; Data; Development; Diabetes Mellitus; Dysautonomias; Electric Stimulation; Electrocardiogram; Employee Strikes; Endothelium; Exhibits; Female; Gene Expression; General Population; Healthcare Systems; Heart Rate; Heart failure; Hormones; Human; Hypertension; Implant; Incidence; Infusion procedures; Injection of therapeutic agent; Knockout Mice; Measurement; Measures; Mediating; Migraine; Motor Activity; Mus; Muscle; Myocardial Infarction; NADPH Oxidase; Nerve; Nervous system structure; Neural Pathways; Neuraxis; Neurogenic Inflammation; Neuromodulator; Neurons; Nociception; Oxidative Stress; Patients; Peripheral; Phenotype; Phenylephrine; Pressoreceptors; Process; Proteins; Protocols documentation; RAMP1; Reactive Oxygen Species; Reflex action; Regulation; Reporting; Research; Resistance; Role; Sensory; Sensory Ganglia; Sensory Nerve Endings; Site; Source; Stroke; Subfornical Organ; Telemetry; Testing; Tissues; Transgenic Mice; Vascular Diseases; Vasodilation; Vasodilator Agents; Veterans; Viral Vector; afferent nerve; autocrine; blood pressure regulation; cell type; cost; heart rate variability; improved; indexing; male; nestin protein; neuromechanism; neuroregulation; novel; osmotic minipump; overexpression; paracrine; paraventricular nucleus; prevent; promoter; receptor; receptor expression; receptor-activity-modifying protein; recombinase; relating to nervous system; release factor; research study; response; telemetering; tempol; therapeutic target; therapy design; trafficking; vascular contributions

DESCRIPTION (provided by applicant): Calcitonin gene-related peptide (CGRP) functions as an autocrine/paracrine factor, hormone and neuro- modulator. While best known for its potent vasodilator activity, CGRP is involved in many neural processes including nociception, neurogenic inflammation, migraine and anxiety. The CGRP receptor has an obligatory requirement for a subunit called Receptor Activity-Modifying Protein 1 (RAMP1). RAMP1 enhances CGRP binding to the receptor and receptor trafficking. While the role of vascular CGRP receptors is well recognized, the role of nervous system CGRP receptors in blood pressure regulation remains unclear. T he proposed studies will test the hypothesis that nervous system CGRP/RAMP1 receptors are powerful modulators of baroreflex sensitivity and autonomic activity capable of preventing or reversing hypertension. The specific aims of the proposed research are to: (1) Determine whether selective overexpression of RAMP1 in the nervous system improves autonomic regulation and attenuates angiotensin II (Ang-II) and phenylephrine-induced hypertension, and conversely if deletion of nervous system RAMP1 impairs auto- nomic regulation and enhances hypertension; (2) Identify nervous system sites of CGRP/RAMP1 receptor expression responsible for autonomic and blood pressure phenotypes in the nervous system-targeted RAMP1 transgenic and knockout mice; and (3) Test the hypothesis that activation of nervous system CGRP/ RAMP1 receptors abrogates Ang-II induced dysautonomia and hypertension by reducing oxidative stress. Our preliminary data indicate that just a 1.5-fold overexpression of RAMP1 in the nervous system improves autonomic regulation and nearly abolishes Ang-II hypertension. We will measure autonomic and cardiovascular phenotypes in male and female RAMP1 transgenic and knockout mice using the nervous system-specific nestin Cre-recombinase to globally target the nervous system and local injections of viral vectors expressing Cre-recombinase to target specific brain regions including brainstem, subfornical organ and paraventricular nucleus. Blood pressure, heart rate, locomotor activity and an array of autonomic indices will be measured in conscious mice implanted with blood pressure and ECG telemeters, both under basal conditions and during hypertension induced by 4-week infusions of Ang-II and phenylephrine delivered by osmotic minipump. To separate effects on sensory vs. central com- ponents of the baroreflex, complementary experiments will be performed in anesthetized mice that include measurements of baroreceptor afferent nerve activity from aortic depressor nerve and reflex changes in heart rate and blood pressure during graded electrical stimulation of baroreceptor afferents. Systemic and central infusions of the antioxidant tempol and central injections of viral vectors encoding siRNAs targeted to NADPH oxidase subunits will be used to determine the role of oxidative stress in mediating autonomic dysregulation and hypertension. Gene expression of CGRP, CGRP receptor subunits, Ang-II receptors, and pro- and anti- oxidant molecules will be measured in the relevant brain regions, sensory ganglia, and peripheral arteries. The significance of identifying nervous system CGRP/RAMP1 receptors as positive modulators of autonomic control relates to their potential as therapeutic targets for treatment of dysautonomia in hyperten- sion, and other pathological states such as heart failure and diabetes. Inhibition of Ang II-mediated effects by activation of CGRP/RAMP1 receptors has widespread implications in hypertension and heart failure.

描述（由申请人提供）： 降钙素基因相关肽（CGRP）充当自分泌/旁分泌因子，激素和神经调节剂。 CGRP虽然以其有效的血管扩张剂活性而闻名，但涉及许多神经过程，包括伤害感受，神经源性炎症，偏头痛和焦虑。 CGRP受体对称为受体活性调节蛋白1（RAMP1）的亚基具有强制性要求。 RAMP1增强了CGRP与受体和受体运输的结合。尽管众所周知，血管CGRP受体的作用尚不清楚，但神经系统CGRP受体在血压调节中的作用尚不清楚。拟议的研究将检验以下假设：神经系统CGRP/RAMP1受体是可预防或逆转高血压的压力反射灵敏度和自主活动的强大调节剂。 拟议研究的具体目的是：（1）确定神经系统中RAMP1的选择性过度表达是否可以改善自主神经调节，并减轻血管紧张素II（ANG-II）和苯肾上腺素诱导的高血压，而相反，如果对神经系统RAMP1的删除会损害自动ramp1 ramp 1会损害自动调节调节和增强hypertensuper hypertensuper hypertensuper hypertemense; （2）鉴定CGRP/RAMP1受体表达的神经系统位点，负责在神经系统靶向的RAMP1转基因和敲除小鼠中负责自主和血压表型； （3）检验以下假设：神经系统CGRP/ RAMP1受体的激活通过减少氧化应激，消除了ANG-II诱导的动作障碍和高血压。我们的初步数据表明，在神经系统中，RAMP1的过度表达仅1.5倍，可以改善自主神经调节，几乎消除了ANG-II高血压。 我们将使用神经系统特异性的Nestin Cre-cobiminase在雄性和女性RAMP1转基因和敲除小鼠中测量自主和心血管表型，以全球范围针对神经系统的神经系统和局部注射病毒载体，表达Cre-cobsinase对靶向特定的脑干区域，包括脑干，亚叶部器官和paravecormularemuls。血压，心率，运动活性和一系列自主指数将在植入血压和ECG遥测者的有意识的小鼠中，无论是在基础条件下以及在4周的Ang-II诱导的高血压下以及由OSMotic Minipump提供的4周输注。为了分开对压力反射的感官与中央组合的影响，将在麻醉的小鼠中进行互补实验，其中包括测量了主动脉抑制神经中的压力感受器传入神经活动，以及在渐变刺激中，主动脉抑制剂神经和反射性变化在渐变性的刺激中，对气压和血压的反射变化。抗氧化剂节奏的全身和中央输注和中央注射靶向NADPH氧化酶亚基的siRNA的病毒载体的中央注射将用于确定氧化应激在介导自主神经失调和高血压中的作用。 CGRP，CGRP受体亚基，ANG-II受体以及促氧化剂分子的基因表达将在相关的大脑区域，感觉神经节和外周动脉中进行测量。 鉴定神经系统CGRP/RAMP1受体作为自主控制的正调节剂的重要性与它们作为治疗高血压治疗功能障碍的治疗靶点的潜力，以及其他病理状态，例如心力衰竭和糖尿病。通过激活CGRP/RAMP1受体抑制ANG II介导的作用对高血压和心力衰竭具有广泛的影响。