PH REGULATION IN VENTRICULAR CELLS

这项研究的长期目标是更好地理解 成年哺乳动物心脏细胞内pH的调节机制 肌肉。在这个项目中，我们主要关注三个方面：1)多肽 心肌细胞膜离子转运体在心脏相中的调控 对照，2)心肌细胞内氢扩散和3)氢扩散 在心肌细胞之间，通过缝隙连接。这些主题是密切相关的 与此相关的是离子转运体引起的PHI变化，这些离子转运体是 最初局限于肌膜下间隙，最终必须到达 细胞内部和邻近细胞充分发挥其生理功能 效果。这些多肽的研究主要集中在血管紧张素II(AngII)、内皮素 1(ET1)和心钠素(ANP)。这些毒剂发挥了广泛的作用 在正常和正常情况下对心脏功能的潜在影响范围 病理情况。我们将研究多肽对HCO3-CI的影响 交换和CI-OH交换。这些酸装载系统是至关重要的 在细胞内碱中毒中调节phi恢复的重要作用 代谢性酸中毒时phi下降。ANP研究的重点是 确定其对Na-H交换、Na-HCO3共转运、HCO3-CI的影响 交换和CI-OH交换。将进行多肽实验 从成人用酶法分离的心室肌和心房肌细胞 兔子。PHI将在单个细胞中使用荧光光谱进行测量 技术和H敏感指示器，SNARF-1。 氢扩散研究旨在描述氢扩散的特征 在不同条件下的单个心肌细胞内和之间 这可能会产生区域性的PHJ梯度。这些实验将会 在单个心肌细胞和成对的肌细胞(室肌和肌细胞对)上进行 Purkinje，兔)使用共聚焦显微镜和SNARF-1来测量PHI。 该项目的结果将产生有关以下方面的新信息 心脏PHI调节系统的激素调节及其作用 细胞内和细胞间的氢扩散以消散局部PHI 渐变。

The long-term goal of this research is to better understand the mechanisms that regulate intracellular pH (pHi) in adult mammalian heart muscle. In this project we focus on three main areas: 1) peptide modulation of sarcolemmal ion transporters involved in cardiac pHi control, 2) H+ diffusion within cardiac cells and 3) H+ diffusion between cardiac cells, through gap junctions. These topics are closely related since the pHi changes induced by the ion transporters, which are initially confined to the subsarcolemmal space, must eventually reach the cell interior and neighboring cells to exert their full physiologic effect. The peptide studies focus on angiotensin II (AngII), endothelin 1 (ET1) and atrial natriuretic peptide (ANP). These agents exert a wide range of potent effects on cardiac function under both normal and pathological conditions. We will examine peptide effects on HCO3-CI exchange and CI-OH exchange. These acid loading systems are critically important in mediating pHi recovery from intracellular alkalosis and the fall in pHi during metabolic acidosis. The ANP studies focus on identifying its effects on Na-H exchange, Na-HCO3 cotransport, HCO3-CI exchange and CI-OH exchange. The peptide experiments will be performed on ventricular and atrial myocytes, enzymatically isolated from adult rabbits. pHi will be measured in single cells using epifluoresence techniques and the H+ sensitive indicator, SNARF-1. The H+ diffusion studies are designed to characterize H+ diffusion within and between single cardiac cells under a variety of conditions which are likely to create regional pHj gradients. The experiments will be performed on both single myocytes and myocyte pairs (ventricular and Purkinje, rabbit) using confocal microscopy and SNARF-1 to measure pHi. The results of this project will yield new information concerning hormonal modulation of cardiac pHi control systems and the action of intracellular and intercellular H+ diffusion to dissipate regional pHi gradients.