PH REGULATION IN VENTRICULAR CELLS

心室细胞的 PH 调节

• 批准号: 2445186
• 负责人: KENNETH W SPITZER
• 金额: $ 11.46万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2445186
• 关键词: acidity /alkalinity; angiotensin II; calmodulin dependent protein kinase; endothelin; fluorescent dye /probe; guinea pigs; heart disorder; heart ventricle; human tissue; laboratory rabbit; membrane potentials; protein kinase C; sarcolemma; single cell analysis; vasoactive agent

DESCRIPTION (adapted from the applicant's abstract): The long term goal of this research is to better understand the mechanisms of intracellular pH (pHi) regulation in adult ventricular muscle. In this project the applicant will focus on two modulators of cardiac pHi control systems, vasoactive peptides (angiotensin II, endothelin 1) and chronic (4-5 days) acid-base disturbances (metabolic acidosis and alkalosis). These peptides are potent positive inotropic agents which exert a wide range of effects on the heart and are currently thought to exacerbate myocardial damage during ischemia/reperfusion. Their cardiac effects may be mediated, in part, by changes in pHi. Similarly, the effect of prolonged acidosis and alkalosis on cardiac pHi control systems may represent an important adaptive response to chronic myocardial ischemia. The applicants will test the hypothesis that both modulators alter the kinetic properties and pHi dependence of Na/H exchange, Na-HCO3 cotransport, and Na- independent Cl-HCO3 exchange. Experiments are also designed to identify the sarcolemmal receptor which mediates the pHi action of the peptides. The applicant will also investigate the intracellular signaling role of Cai, calmodulin, Ca/calmodulin-dependent protein kinase II, and protein kinase C in mediating the pHi effects of ATII and ET1. The experiments will be performed at 37oC on ventricular myocytes, enzymatically isolated from normal adult rabbits, guinea pigs, and humans (only rabbits will be used in the chronic acid-base studies). Intracellular activities of H+ and Na+ will be measured with the fluorescent indicators (SNARF-1, BCECF) and SBFI, respectively. In some experiments, measurement of pHi and Nai will be made during internal dialysis of cells with a suction pipette. A rapid solution switcher will be used for rapid (less than 3 msec) external application of the peptides.

描述（改编自申请人的摘要）：长期目标 这项研究的目的是更好地了解细胞内的机制， 成人心室肌的pH（pHi）调节。本工程 申请人将关注心脏pHi控制系统的两种调节剂， 血管活性肽（血管紧张素II，内皮素1）和慢性（4-5 天）酸碱紊乱（代谢性酸中毒和酸中毒）。这些 肽是有效的正性肌力药， 对心脏的影响，目前认为会加剧 心肌缺血/再灌注损伤。它们对心脏的影响可能 在某种程度上，是由pHi的变化所介导的。同样， 对心脏pHi控制系统的长期酸中毒和酸中毒可能 代表了对慢性心肌缺血的重要适应性反应。 申请人将检验两种调节剂均改变细胞内蛋白质的表达的假设。 Na/H交换的动力学性质和pHi依赖性，Na-HCO 3 共转运和Na-非依赖性Cl-HCO 3交换。实验也 旨在鉴定介导pHi的肌膜受体 肽的作用。申请人还将调查 Cai的细胞内信号作用，钙调蛋白，Ca/钙调蛋白依赖性 蛋白激酶II和蛋白激酶C介导的pHi效应 ATII和ET 1。实验将在37 ℃下进行， 从正常成年兔，豚鼠， 和人（慢性酸碱研究中仅使用家兔）。 H+和Na+的细胞内活性将用 荧光指示剂（SNARF-1，BCECF）和SBFI。在一些 实验中，将在内部实验期间测量pHi和Nai。 用吸管透析细胞。快速解决方案切换器将 用于快速（小于3毫秒）外部应用 缩氨酸