pH REGULATION IN HEART CELLS

这个项目的总体长期目标是更好地了解控制 细胞内和细胞内pH，以及细胞外和细胞内pH对心肌细胞的影响 钙处理。这些结果将具有相当基本的生理重要性，并且具有很高的相关性。 心脏的病理生理状况。实验将在心房和浦肯野肌细胞上进行 利用共聚焦成像和荧光技术测量细胞内pH、钙和钠 (仅限荧光)在单个细胞中。笼子质子的闪光光解将被用来产生区域 细胞内[H]增加。荧光测量将与电流钳位和电压相结合- 钳制记录动作电位和全细胞膜离子电流。具体的 目标包括： 1.研究心房和浦肯野细胞的细胞内pH调节。详细的功能描述 肌膜pH控制转运蛋白将被执行。结果将被用来构建计算 细胞内pH调节的模型。 2.电刺激NBC对心房和浦肯野细胞的电效应两国之间的关系 将确定NBC电流和动作电位复极及其受内部pH的调节。 3.研究心房和浦肯野细胞内和细胞间质子扩散的特征。两国之间的关系 将确定细胞内pH和细胞内质子迁移率，以及它们之间的关系 心肌细胞对的细胞内pH和连接质子渗透性/通量。结果将产生新的见解 关于这些细胞类型中pH的空间控制。 4.研究酸中毒对心房和浦肯野细胞钙离子转运的影响。整体的影响- 细胞内外酸中毒对钙瞬变、钙电流和肌浆钙处理的影响将被确定。 心脏产生电信号和收缩的能力受到心脏酸碱度的强烈影响 单个细胞内外的液体。这项研究旨在更好地了解其后果 过度积累的酸和碱对心脏细胞功能的影响，并确定细胞如何能够 调节它们体内的PH值。

The overall long-term objective of this project is to better understand the cellular mechanisms that control nter- and intracellular pH and to determine the effects of pH (extra- and intracellular) on cardiac myocyte calcium handling. The results will have considerable basic physiological importance and are highly relevant to cardiac pathophysiological conditions. Experiments will be performed on atrial and Purkinje myocytes using confocal imaging and epifluorescence techniques to measure intracellular pH, calcium and sodium (epifluorescence only) in individual cells. Flash-photolysis of caged protons will be used to generate regional ncreases in intracellular [H]. Fluorescence measurements will be coupled with current-clamp and voltage- clamp recordings of action potentials and whole cell membrane ionic currents, respectively. The specific aims include: 1. Characterize intracellular pH regulation in atrial and Purkinje cells. A detailed functional characterization of sarcolemmal pH control transporters will be performed. The results will be used to construct computational models of intracellular pH regulation. 2. Characterize electrical effects of electrogenic NBC in atrial and Purkinje cells. The relationship between NBC current and action potential repolarization and its modulation by internal pH will be determined. 3. Characterize intra- and intercellular proton diffusion in atrial and Purkinje cells. The relationship between intracellular pH and intracellular proton mobility will be determined, as well as the relationship between intracellular pH and junctional proton permeability/flux in myocyte pairs. The results will yield new insight concerning spatial control of pH in these cell types. 4. Characterize the effect of acidosis on calcium handling in atrial and Purkinje cells. The effects of whole- cell extra- and intracellular acidosis on the Ca transient, Ca current and SR Ca handling will be determined. The ability of the heart to generate electrical signals and contract is strongly influenced by the pH of the fluids inside and outside of individual cells. This research is designed to better understand the consequences of excessive accumulation of acid and base on heart cell function and to determine how the cells are able to regulate their internal pH.