CHARACTERIZATION OF THE ELECTROGENIC SODIUM-PUMP IN CARDIAC PURKINJE-FIBERS
CHARACTERIZATION OF THE ELECTROGENIC SODIUM-PUMP IN CARDIAC PURKINJE-FIBERS
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DOI：
10.1113/jphysiol.1980.sp013298
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发表时间：
1980-01-01
影响因子：
5.5
通讯作者：
LEDERER, WJ
中科院分区：
文献类型：
--
作者：
EISNER, DA;LEDERER, WJ
采用2微电极电压钳技术对绵羊心脏浦肯野纤维中的钠泵进行了检测。在将外部K浓度[K]o降低至零2分钟或更长时间后，随后添加激活剂阳离子（已知在其他制剂中激活Na泵）会产生向外电流的瞬态增加。这种向外的瞬态电流被10-5 m的蝶蝶苷所消除。这种向外电流的瞬态增加是由于暴露于0-Ko后[Na]1升高对Na泵的瞬态刺激造成的。在0 ~ 40 mM范围内增加[Rb] 0或[Cs] 0会增加电致钠泵电流瞬态的衰减速率。用一个简单的模型，电致钠泵电流瞬态的衰减速率常数显然是衡量钠泵外部部位活化程度的一个很好的指标。在给定的激活剂阳离子浓度下，Rbo比Cso产生更大的Na泵激活。在2-40 mM范围内，钠泵的耦合比与Rbo或Cso无关。在考虑的范围内，耦合比与Na1无关。当使用Rb或Cs作为激活剂时，电致钠泵电流瞬态可以很好地测量Na泵的活性。该方法可用于完整制备中，以研究钠泵速率与其他细胞事件（如张力调节）之间的关系。
The Na pump is examined in sheep cardiac Purkinje fibers using a 2 microelectrode voltage clamp technique. After reducing the external K concentration, [K]o, to zero for 2 min or more, subsequent addition of an activator cation (known to activate the Na pump in other preparations) produces a transient increase of outward current. This outward current transient is abolished by 10-5 M-strophanthidin. This transient increase of outward current is a result of a transient stimulation of the Na pump by the raised [Na]1 following exposure to 0-Ko. Increasing [Rb]o or [Cs]o over the range of 0-40 mM increases the rate of decay of the electrogenic Na pump current transient. Using a simple model the decay rate constant of the electrogenic Na pump current transient is apparently a good measure of the degree of activation of the external site of the Na pump. At a given concentration of activator cation, Rbo produces a greater activation of the Na pump than does Cso. The coupling ratio of the Na pump is independent of Rbo or Cso over the range 2-40 mM. The coupling ratio is independent of Na1 over the range considered. The electrogenic Na pump current transient provides a good measure of the activity of the Na pump when Rb or Cs are used as activator cations. This measure can be used in the intact preparation to investigate the relationship between Na pump rate and other cellular events, such as the regulation of tension.