PH REGULATION IN VENTRICULAR CELLS

哺乳动物心室肌的电特性和力学特性 肌肉明显受到局部pH值变化的影响。 敏感性可能显著有助于心肌 伴有心室缺血的功能障碍。 因此， 用于控制细胞内酸碱状态的系统 心室肌对于维持 心脏功能正常 细胞内pH（pH 1）的机制 膜电位和激素的调控 在哺乳动物心室肌中未得到解决， 这个项目的重点。 第二个目标是量化 pH与收缩的关系 为了避免这些问题 与多细胞心脏制备相关，所有实验 将在单个心室细胞上进行。 荧光染料 离子选择性微电极将用于测量 人细胞内H ~+、Na ~+、Cl ~-、HCO ~ 3和Ca ~（2+）活性 细胞 膜电位将使用全细胞 拍片技术和最近开发的快速灌注 系统将用于改变内部的外部溶液成分 7毫秒。 细胞收缩将通过新开发的 视频运动检测器 预计结果将提供新的 深入了解离子需求，激素控制和“电压 哺乳动物心室pH调节系统敏感性 肌肉. 结果还应产生新的信息， 在生理现实条件下，关于pH 1- 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.