Central nicotinic receptors in hypertension

高血压中枢烟碱受体

• 批准号: 7393843
• 负责人: PALMER William TAYLOR
• 金额: $ 45.83万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7393843
• 关键词: Ablation; Age; Animals; Area; Autoradiography; Behavioral; Biological Assay; Blood Pressure; Brain; C Fiber; California; Candidate Disease Gene; Capsaicin; Cardiovascular system; Cells; Chromosomes, Human, Pair 8; Code; Complement; Confocal Microscopy; Congenic Strain; Conscious; DNA Resequencing; Disease; Dopamine; Event; Gene Cluster; Gene Transfer; Genes; Genetic Models; Genetic Polymorphism; Human; Hypertension; Immunohistochemistry; Immunoprecipitation; Inbred SHR Rats; Laboratories; Ligand Binding; Link; Localized; Maps; Measurement; Measures; Mediating; Mediator of activation protein; Microdialysis; Molecular; Monitor; Neurons; Neurotransmitter Receptor; Nicotine; Nicotinic Agonists; Nicotinic Receptors; Norway; Numbers; Pathway interactions; Phenotype; Population; Potassium Channel; Quantitative Trait Loci; Rat Strains; Rattus; Receptor Gene; Reflex action; Relative (related person); Spinal; Spinal Cord; Substance P Receptor; System; Techniques; Tobacco; Work; base; blood pressure regulation; cell type; congenic; familial hypertension; immunocytochemistry; neurotransmitter release; nociceptive response; presynaptic; progenitor; programs; receptor; response; somatosensory; spinal pathway; substance P-saporin; trait

Studies in the continuing project period will be based primarily on a critical finding, made over the last year with a congenic strain of rats derived from the Spontaneously Hypertensive Rat (SHR) and Brown Norway parentage. This strain contains a 3 lcM replacement in chromosome 8 into the SHR background, and quite fortuitously this region contains a cluster of nicotinic acetylcholine receptor genes that encode receptor subunits expressed in the CNS (alpha3, beta4 and alpha7). These animals show diminished blood pressure (systolic and diastolic) relative to their SHR counterparts. More importantly, intrathecal administration of nicotinic agonists shows markedly diminished pressor and nociceptive responses. For sometime we have felt that the SHR trait was one of enhanced excitability, and as the animal ages, blood pressure becomes one manifestation of this. If we consider more widespread excitability responses, loci of amplification evident in the presynaptic control of neurotransmitter release would be a logical starting point. Recent work has also documented that most nicotinic receptors appear to lie presynaptically in spinal and supraspinal regions. We have chosen to study the spinal system, not because we believe it to be an area that globally controls hypertension, but rather pressor responses to nicotinic agonists injected into segmental cord areas can be monitored in the conscious animal. In turn, measurements of target receptor number, their subtypes, cellular responses (ie: release of neurotransmitters detected in microdialysates), and the cellular localization of neurotransmitter and receptor subtype in various lamina and cell types in the cord have been and will be measured. Accordingly, we propose to more fully characterize the pressor response in conscious SHR and SHR-Lx rats, and then begin to localize the gene(s) responsible for the different pressor response by delimiting the region around the nicotinic receptor gene cluster. If the response remains associated with the AChR gene substitution, we then will attempt to identify which of the three genes are involved, through a characterization of the coding and critical noncoding regions. Other regions showing quantitative trait loci will also be investigated. Since the window of the response to spinal nicotinic agonists is augmented, we will characterize the localization of receptors and transmitters in this region through the use of immunocytochemistry and confocal microscopy. In addition, relatively specific cell ablation is possible in the spinal cord through the use of capsaicin and a Substance P-saporin conjuate, and by comparing altered pressor responses of treated and untreated animals, we should be able to map spinal pathways and receptor subtypes involved in the altered responses.

在持续项目期间的研究将主要基于一个关键发现，该发现是在去年以自发性高度大鼠（SHR）和棕色挪威父母的先天大鼠菌株进行的。该菌株在8号染色体中包含3 LCM替代SHR背景，并且很幸运地，该区域包含一组烟碱乙酰胆碱受体基因，这些基因编码在CNS中表达的受体亚基（alpha3，beta4和alpha7）。这些动物相对于其SHR对应物显示出血压降低（收缩压和舒张压）。更重要的是，烟碱激动剂的鞘内给药表现出明显减少的压力和伤害性反应。有一段时间，我们认为SHR性状是增强的兴奋性之一，随着动物的年龄，血压成为一种体现。如果我们考虑更广泛的兴奋性响应，那么在神经递质释放的突触前控制中明显的放大基因座将是一个逻辑上的起点。最近的工作还证明，大多数烟碱受体似乎在脊柱和脊柱上部区域偏见。我们选择研究脊柱系统，不是因为我们认为它是全球控制高血压的区域，而是在有意识的动物中可以监测注射到节段性绳索区域的烟碱激动剂对烟碱激动剂的反应。反过来，对靶受体数，亚型，细胞反应的测量（即：在微疗法中检测到的神经递质的释放）以及在绳索中各种层状和细胞中神经递质和受体亚型的细胞定位已被测量和测量。因此，我们建议在有意识的SHR和SHR-LX大鼠中更充分地表征施加反应，然后开始通过划定烟碱受体基因簇周围的区域来定位负责不同的压力反应的基因。如果响应与ACHR基因取代相关，那么我们将通过表征编码和关键的非编码区域来识别涉及的三个基因中的哪个中的哪个。还将研究显示定量性状基因座的其他区域。由于增强对脊柱烟碱激动剂的反应窗口，我们将通过使用免疫细胞化学和共聚焦显微镜来表征该区域受体和发射器的定位。此外，通过使用辣椒素和p-杀伤蛋白结合物，并通过比较处理和未经处理的动物的压力响应改变，我们应该能够映射脊柱途径和受体亚型涉及变化的反应。