CARDIAC CELL VOLUME REGULATION IN HEALTH AND DISEASE

健康和疾病中的心肌细胞体积调节

• 批准号: 2459970
• 负责人: CLIVE M BAUMGARTEN
• 金额: $ 21.75万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-16 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2459970
• 关键词: cell morphology; cell osmotic pressure; cellular pathology; fluorescent dye /probe; heart cell; heart metabolism; ion transport; laboratory rabbit; lipid metabolism; membrane permeability; microelectrodes; myocardial ischemia /hypoxia; reperfusion; stretch receptors; video microscopy; voltage /patch clamp

DESCRIPTION (adapted from the applicant's abstract): The proposed studies focus on one aspect of myocardial injury, cardiac cell edema, and the underlying mechanisms of cell volume regulation. Lipid metabolites, including lysolipids derived from diacyl and plasmalogen species (e.g., lysophosphatidylcholine, lysoplasmenylcholine), long chain acylcarnitine, and arachidonic acid are reported to rapidly accumulate during ischemia and reflow and have been implicated in the ensuing electrophysiological disturbances. The central question to be evaluated here is: Do ischemic lipid metabolites disrupt cardiac cell volume regulation under isosmotic and anisosmotic conditions? It is postulated that lipid metabolites: (1) Cause cell swelling in the absence of an osmotic gradient by altering passive ion permeation and ion transport; (2) Exacerbate cell swelling in the presence of an osmotic gradient by increasing the permeability of cardiac cell membranes to water (i.e., hydraulic conductivity); and (3) Alter the response to swelling by modulating the function of stretch-activated channels and other ion permeation processes. The proposed experiments combine novel techniques to address the following aims: (1) The effects of lipid metabolites on cell volume under isosmotic conditions will be measured by digital video microscopy; (2) Hydraulic conductivity (water permeability) will be calculated from the kinetics of volume changes in response to osmotic stress; (3) Transport processes involved in lipid metabolite-induced volume changes will be identified by ion substitution studies and specific blockers; (4) Ion selective microelectrodes will be used to measure changes in the intracellular ion activities of K+, Na+, and Cl-; (5) The effect of metabolites on stretch- activated currents will be determined by simultaneous perforated-patch voltage clamp and cell volume measurements, and the magnitude of volume changes and currents will be related; and (6) The effects of lipid metabolites on sarcolemmal fluidity will be determined by fluorescence recovery after photobleaching (FRAP) in intact cells.

简介(改编自申请人的摘要)：建议 研究集中在心肌损伤的一个方面，即心肌细胞水肿， 以及细胞体积调节的潜在机制。脂类 代谢物，包括来自双酰基和血浆蛋白原的溶菌脂 物种(如溶血磷脂酰胆碱、溶血磷脂酰胆碱)，长链 据报道，酰基肉碱和花生四烯酸会迅速积累 在缺血和复流期间，并已牵涉到随后的 电生理障碍。要评估的中心问题 以下是：缺血性脂质代谢产物是否会破坏心肌细胞体积 等渗和非等渗条件下的调节？这是假定的 这种脂质代谢产物：(1)在没有AFP的情况下会引起细胞肿胀 通过改变被动离子渗透和离子传输的渗透梯度； (2)在渗透梯度存在的情况下通过以下方式加剧细胞肿胀 增加心肌细胞膜对水的渗透性(即， 水力传导性)；和(3)通过改变对膨胀的反应 调节牵张激活通道和其他离子的功能 渗透过程。拟议的实验结合了新的技术 解决以下目标：(1)脂类代谢物的影响 等渗条件下细胞体积的数字化测量 视频显微镜；(2)水力传导性(透水性)将 根据渗透压下体积变化的动力学进行计算 应激；(3)脂代谢产物诱导的转运过程 体积变化将通过离子替代研究和 特定阻滞剂；(4)离子选择性微电极将用于 测定细胞内K+、Na+、Cl-离子活性的变化； (5)代谢产物对牵张激活电流的影响 由同时穿孔膜片电压钳和电池决定 体积测量，以及体积变化和电流的大小 将是相关的；以及(6)脂代谢产物对 肌膜流动性将通过荧光恢复测定后 完整细胞的光漂白(FRAP)。