PH REGULATION IN VENTRICULAR CELLS

哺乳动物心脏的电学和力学特性 肌肉明显受到局部pH值变化的影响。这 敏感性可能是导致心肌梗死的重要原因 功能障碍伴发心肌缺血。因此，蜂窝 用于控制细胞内酸碱状态的系统 心室肌对维持心脏功能至关重要 心脏功能正常。细胞内pH(PH1)的作用机制 膜电位和激素的调节及其调控 在哺乳动物的心室肌中未被分解，是主要的 这个项目的重点。次要目标是量化 PH值与收缩的关系。为了避免这些问题 与多细胞心脏制剂有关，所有实验 将在单个心室细胞上进行。荧光染料 并将使用离子选择微电极来测量 个体细胞内H、Na、Cl、HCO3和Ca的活性 细胞。膜电位将由全细胞控制 贴片拍打技术和最近发展的快速灌流 系统将用于在内部更改外部溶液组成 7毫秒。细胞收缩将通过一种新开发的 视频运动检测器。预计结果将提供新的 洞察离子需求、荷尔蒙控制和“电压” 哺乳动物心室的pH敏感性及其调节系统 肌肉。结果还应该产生新的信息，获得 在生理现实条件下，关于PH1- 心室肌的收缩关系。

The electrical and mechanical properties of mammalian ventricular muscle are markedly affected by changes in local pH. This sensitivity may significantly contribute to the myocardial dysfunction accompanying ventricular ischemia. Hence, the cellular systems for controlling the intracellular acid-base status of ventricular muscle are critically important for maintenance of normal heart function. The mechanism of intracellular pH (pH1) regulation and its modulation by membrane potential and hormones is unresolved in mammalian ventricular muscle and is the principal focus of this project. The secondary objective is to quantify the relationship between pH and contraction. To avoid the problems associated with multicellular cardiac preparations, all experiments will be conducted on single ventricular cells. Fluorescent dyes and ion-selective-microelectrodes will be used to measure intracellular activities of H+, Na, Cl, HCO3 and Ca in individual cells. Membrane potential will be controlled using whole-cell patch clap techniques and a recently developed rapid perfusion system will be used to change external solution composition within 7 msec. Cell contraction will be monitored with a newly developed video motion detector. The results are expected to provide new insight into the ionic requirements, hormonal control and"voltage sensitivity of pH, regulatory systems in mammalian ventricular muscle. The results should also yield new information, obtained under physiologically realistic conditions, concerning the pH1- contraction relationship in ventricular muscle.