RECEPTORS, G PROTEINS, AND CARDIAC TRANSPLANTATION

受体、G 蛋白和心脏移植

• 批准号: 3087776
• 负责人: EVAN LOH
• 金额: $ 7.7万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3087776
• 关键词: G protein; adenylate cyclase; adrenergic receptor; affinity chromatography; autonomic disorder; autonomic reflex; autoradiography; denervation; densitometry; drug adverse effect; enzyme mechanism; gel electrophoresis; heart innervation; heart transplantation; human subject; immunosuppressive; laboratory rat; messenger RNA; mixed tissue /cell culture; muscarinic receptor; nuclear runoff assay; nucleic acid hybridization; parasympathetic nervous system; receptor coupling; sympathetic nervous system; western blottings

The transplanted human heart demonstrates abnormalities in autonomic responsiveness, the mechanism of which remains unknown. The long-term objectives of these studies are to understand the mechanisms by which sympathetic and parasympathetic innervation affect the regulation of autonomic responses of the human myocardium. Adrenergic and muscarinic responses of mammalian myocardium are coupled to intracellular functions via guanine nucleotide binding proteins. Recent studies in chick,, rat and human myocardium have suggested that innervation of the heart may play a role in regulating the responsiveness of the heart to autonomic stimuli via changes in receptors and G-protein-effector interactions. We plan to utilize three model systems to investigate the role of innervation and drug therapy in regulating autonomic balance in the transplanted myocardium. Endomyocardial biopsy specimens from human hearts following orthotopic cardiac transplantation, will be used to test the hypotheses that denervation leads to alteration in autonomic response by inducing changes in levels of adrenergic and muscarinic receptors,, changes in levels of G-proteins and their coupling to adenylate cyclase activity and that these alterations are associated with changes in the levels of the messenger RNA (mRNA) coding for these receptors and G-proteins. Since it will be impossible to evaluate the role of immunosuppressive agents in mediating the changes in autonomic responsiveness seen in the transplanted human myocardium, we will use a model of heterotopic cardiac transplantation in the Lewis rat to investigate the effects of denervation, with and without immunosuppressive agents on autonomic receptor-effector coupling. In order to determine the role of innervation in modulating the autonomic responsiveness of the heart, we will utilize a co-culture system of neonatal rat myocytes and sympathetic ganglia. We will conduct these studies to determine if innervation alters the levels of receptors and their coupling via G-proteins to adenylate cyclase activity and whether these changes represent a reversal of the effects observed in denervated myocardium. These studies should enhance our understanding of the basis of autonomic responsiveness of the heart, and the role that innervation and denervation may play in regulating autonomic balance of the heart.

移植的人类心脏显示自主神经异常 反应性，其机制尚不清楚。 长期来看 这些研究的目的是了解其机制 交感神经和副交感神经支配影响调节 人类心肌的自主反应。 肾上腺素和毒蕈碱 哺乳动物心肌的反应与细胞内功能耦合 通过鸟嘌呤核苷酸结合蛋白。 最近对鸡、大鼠和 人类心肌表明，心脏的神经支配可能发挥着重要作用 通过调节心脏对自主神经刺激的反应性的作用 受体和 G 蛋白效应子相互作用的变化。 我们计划利用三个模型系统来研究 神经支配和药物治疗调节自主神经平衡 移植的心肌。 人类心脏的心内膜心肌活检标本 原位心脏移植后，将用于测试 假设去神经支配通过以下方式导致自主反应的改变 诱导肾上腺素能和毒蕈碱受体水平的变化 G 蛋白水平及其与腺苷酸环化酶活性的耦合 并且这些变化与 编码这些受体和 G 蛋白的信使 RNA (mRNA)。 自从它 无法评估免疫抑制剂的作用 调节移植物中自主反应的变化 人类心肌，我们将使用异位心脏模型 移植到Lewis大鼠中以研究去神经支配的影响， 自主神经受体效应器上有或没有免疫抑制剂 耦合。 为了确定神经支配在调节中的作用 心脏的自主反应，我们将利用共培养系统 新生大鼠肌细胞和交感神经节。 我们将进行这些 研究以确定神经支配是否改变受体的水平 它们通过 G 蛋白与腺苷酸环化酶活性偶联，以及是否 这些变化代表了在去神经支配中观察到的效果的逆转 心肌。 这些研究应该增强我们对基础的理解 心脏的自主反应性，以及神经支配和 去神经可能有助于调节心脏的自主神经平衡。