Na,K-ATPase studies on optic nerve head astrocytes

描述（由申请方提供）：拟对视神经头星形胶质细胞中的Na，K-ATP酶进行研究。星形胶质细胞在神经元微环境中调节pH、钾、钙和谷氨酸的能力与Na，K-ATP酶有关。星形胶质细胞表达两种Na，K-ATP酶亚型α 1和α 2。这两种亚型似乎有不同的功能，但我们没有完整的信息，他们各自的作用或星形胶质细胞生理学的影响。Na，K-ATP酶α 1具有重要的管家功能，调节细胞内钠的浓度。我们对Na，K-ATP酶α 2亚型特别感兴趣，因为初步研究表明它具有不同的作用。它不 似乎控制细胞范围内的钠浓度，但相反，我们认为Na，K-ATP酶α 2可能以某种方式专门化，使其对谷氨酸摄取，细胞钙平衡和可能的细胞生长产生重大影响。提出实验来研究星形胶质细胞如何具有损害细胞积累细胞外钾、转运谷氨酸和质子以及调节细胞质钙的能力的潜力。我们还提出了研究，以检查潜在的损害的Na，K-ATP酶功能的体外事件的ATP耗竭和一氧化氮暴露，并在体内细胞内压力升高。其目标是：目的1.确定Na，K-ATP酶α 2活性对谷氨酸摄取的影响;目的2.确定Na，K-ATP酶α 2活性的改变如何导致细胞质钙储备的变化以及随后星形胶质细胞行为的变化;目的3.研究Na，K-ATP酶活性异常如何影响质子转运机制;目的4.研究导致Na，K-ATP酶功能或表达异常的因素。

DESCRIPTION (provided by applicant): Studies are proposed on Na, K-ATPase in optic nerve head astrocytes. The ability of astrocytes to regulate pH, potassium, calcium and glutamate in the neuronal microenvironment is linked to Na, K-ATPase. Astrocytes express two Na,K-ATPase isoforms alpha1 and alpha2. The two isoforms appears to have different functions but we do not have complete information on their respective roles or the implications for astrocyte physiology. Na,K-ATPase alpha1 has a vital housekeeping function, regulating the cell-wide concentration of cytoplasmic sodium. We are particularly interested in the Na,K-ATPase alpha2 isoform because Preliminary Studies suggest it has a different role. It does not appear control cell-wide sodium concentration but instead we think Na,K-ATPase alpha2 may be specialized in a way that causes it to have a major influence on glutamate uptake, cell calcium balance and possibly cell growth. Experiments are proposed to study how and astrocytes has the potential to impair the ability of the cell to accumulate extracellular potassium, transport glutamate and protons and regulate cytoplasmic calcium. We also propose studies to examine the potential impairment of Na,K-ATPase function by in vitro episodes of ATP depletion and nitric oxide exposure and by elevated intracellular pressure in vivo. The aims are: (AIM 1) Determine the influence of Na, K-ATPase alpha2 activity on glutamate uptake; (AIM 2) Determine how altered Na,K-ATPase alpha2 activity leads to changes in cytoplasmic calcium stores and subsequent changes in astrocyte behavior; (AIM 3) Study how abnormal Na,K-ATPase activity could impact proton transport mechanisms; (AIM 4) Study the factors that cause abnormal Na,K-ATPase function or expression.