SODIUM PUMP ISOFORMS AND CARDIAC FUNCTION

描述（改编自申请人摘要）：申请人提出 研究α 3 Na，K-ATP酶亚型在心脏中的作用，重点是 检验α 3 Na，K-ATP酶同工型是 适应于在压力条件下发挥作用，因为它具有较低的Na 亲和力高于α 1和α 2同种型。 具体目标是：1） 为了研究α 3的强制过表达如何影响离子稳态， 在基因操作的小鼠心脏细胞和灌注的收缩性 2）确定防止Na，K-ATP酶亚型的作用 30日龄心脏中通过强制α 3过表达进行转换 3）开发抑制新生儿中α 3泵的方法 大鼠心脏细胞，并确定这种功能的后果， 镇压 方法：结构-功能关系将通过 研究转基因小鼠和培养的大鼠心脏细胞， 其中α 3/α 1同种型表达比率已经通过以下方式进行操纵： 反义技术 生活中细胞内阳离子水平和通量 将用荧光光谱法研究细胞。 那么， 将比较哇巴因对正常和转基因心脏收缩力的影响 使用视频显微镜和隔离心脏灌注。

DESCRIPTION (adapted from the applicant's abstract): The applicant proposes to study the role of the alpha3 Na,K-ATPase isoform in the heart focusing on testing the overall hypothesis that the alpha3 Na,K-ATPase isoform is adapted to function under conditions of stress since it has a lower Na affinity than alpha1 and alpha2 isoforms. The specific objectives are: 1) To examine how forced overexpression of alpha3 affects ionic homeostasis and contractility in genetically manipulated mouse heart cells and perfused hearts; 2) To determine the effect of preventing the Na,K-ATPase isoform switch by forcing overexpression of alpha3 in hearts of 30-day-old transgenic mice; 3) To develop methods to suppress alpha3 pumps in neonatal rat heart cells and determine the functional consequences of such suppression. Methods: Structure-function relationships will be probed by studying both heart cells from transgenic mice, and cultured rat heart cells in which the alpha3/alpha1 isoform expression ratio has been manipulated via antisense technology. Intracellular cation levels and fluxes in living cells will be studied with fluorescence spectroscopy. Then the effects of ouabain on contractility in normal and transgenic hearts will be compared using videomicroscopy and isolated heart perfusion.