METABOLIC AND HORMONAL CONTROL OF CARDIAC CONTRACTION

心脏收缩的代谢和激素控制

• 批准号: 3340147
• 负责人: Gary Brooker
• 金额: $ 28.86万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1981
• 资助国家: 美国
• 起止时间: 1981-09-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3340147
• 关键词: acetylcholine; action potentials; adenylate cyclase; antiadrenergic agents; cardiovascular agents; cyclic AMP; cyclic GMP; cyclic nucleoside monophosphate; digitalis; drug metabolism; guanosine monophosphate; heart contraction; heart pharmacology; hormone regulation /control mechanism; insulin; ion exchange chromatography; isoproterenol; microelectrodes; myocardium; phosphodiesterase inhibitors; phosphorylation; radioimmunoassay; radiotracer

During the last three years of this grant we discovered that the inotropic action of Beta-adrenergic agonists consists of separate and dissociable functional alterations of sarcolemmal calcium flux and sarcoplasmic reticulum calcium sequestration. Zero sodium solutions eliminate the positive inotropic action of isoproterenol, the stimulation of the slow inward calcium current and markedly reduce the rise in intracellular cyclic AMP without altering the relaxant effect of isoproterenol which decreases the time for peak tension development. Our recent success in the development of low background, high affinity reversible and irreversible probes for the Beta-adrenergic receptor and projected additional high molecular weight, electron dense and fluorescent probes should facilitate the functional and anatomical localization of Beta-adrenergic receptors and sites of cyclic AMP generation in the myocardium. The original observation by this laboratory that RNA and protein synthesis inhibitors prevent catecholamine refractoriness will be a focus for studies of the mechanism of catecholamine refractoriness. There is widespread confirmation that RNA and protein synthesis are involved in refractoriness in a wide variety of cell types and hormones. While cyclase can be isolated which shows some refractoriness, the quantitative aspects reflect only a fraction of the dramatic rise in isoproterenol stimulated cyclic AMP accumulation and subsequent refractoriness observed in whole cells. Because of this, acute cell fusion experiments have been initiated and have already demonstrated the ability to acutely transfer altered responsiveness from one cell to the next. This technique will be used to identify and isolate the factor(s) which impart refractoriness. Additional experiments are proposed in this supplemental application to further evaluate our recent finding that long term treatment of cultured cells with isoproterenol or cholera toxin results in a cyclic AMP mediated loss of Beta-adrenergic receptor binding sites. The mechanism of cyclic AMP mediated receptor loss will be investigated to determine if cyclic AMP reduces receptor synthesis or modifies receptor binding by some covalent modification of the receptor.

在这笔资助的最后三年中，我们发现正性肌力 β-肾上腺素能激动剂的作用包括单独的和可解离的 肌膜钙通量和肌浆的功能改变 网状钙螯合。 零钠溶液消除了 异丙肾上腺素的正性肌力作用，缓慢的刺激 内向钙电流并显着降低细胞内循环的升高 AMP 不会改变异丙肾上腺素的松弛作用，从而降低 峰值张力发展的时间。 我们最近在 低背景、高亲和力、可逆和不可逆的发展 β-肾上腺素能受体探针并预计额外高 分子量、电子密度和荧光探针应有助于 β-肾上腺素能受体的功能和解剖定位 心肌中环磷酸腺苷的生成位点。 最初的观察 通过该实验室，RNA 和蛋白质合成抑制剂可以防止 儿茶酚胺难治性将成为机理研究的重点 儿茶酚胺难治性。 广泛证实 RNA 和蛋白质合成与多种疾病的不应期有关 细胞类型和激素。 虽然可以分离环化酶，这表明一些 耐火度，定量方面仅反映了一小部分 异丙肾上腺素的急剧增加刺激了环磷酸腺苷的积累 随后在全细胞中观察到不应性。 正因为如此，急性 细胞融合实验已经启动并已经证明 将改变的反应性从一个细胞敏锐地转移到另一个细胞的能力 下一个。 该技术将用于识别和隔离因素 赋予耐火性。 本文提出了额外的实验 补充申请进一步评估我们最近的发现 用异丙肾上腺素或霍乱毒素对培养细胞进行长期治疗 导致环 AMP 介导的 β-肾上腺素能受体结合丧失 网站。 环AMP介导的受体丢失的机制是 研究以确定环 AMP 是否会减少受体合成或 通过受体的一些共价修饰来修饰受体结合。