Increments in the concentrations of sodium and calcium in cell compartments of stretched mouse ventricular myocytes
Increments in the concentrations of sodium and calcium in cell compartments of stretched mouse ventricular myocytes
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DOI：
10.1016/s0143-4160(03)00084-8
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发表时间：
2003-08-01
期刊：
影响因子：
4
通讯作者：
Gallitelli, MF
中科院分区：
文献类型：
--
作者：
Kondratev, D;Gallitelli, MF
增加细胞内总钠[Na]和钙浓度[Ca]，预期从非选择性阳离子电流I-SAC的拉伸激活，通过电子探针显微分析（EPMA）与16 nm的空间分辨率进行定量。电压钳位小鼠心室肌细胞通过增加贴片移液管和细胞附着的触针之间的距离20%。拉伸2分钟后，将细胞休克冷冻用于EPMA。拉伸增加[Na]从23到48 mM，中央胞质溶胶从17到29 mM，中央线粒体从10到21 mM，核膜从43到71 mM，细胞核从12到24 mM。拉伸增加总[Ca]在外周胞质溶胶从570到840 μ M，中央胞质溶胶从404到840 μ M。线粒体[Ca]无变化。牵张可使细胞核（180 ~ 300 μ M）和核膜（933 ~ 1530 μ M）的[Ca]增加，提示核膜具有钙屏障功能，用50 μ M链霉素阻断I-SAC可消除牵张引起的[Na]增加，提示I-SAC内流Na+可能是牵张引起[Na]增加的机制。链霉素消除了牵张诱导的外周而非中央胞质[Ca]增加，似乎ISAC的其他机制参与了中央[Ca]升高。(C)2003爱思唯尔科技有限公司版权所有。
Increments in total intracellular sodium [Na] and calcium concentration [Ca], expected from stretch activation of non-selective cation current I-SAC, were quantified by means of electron probe microanalysis (EPMA) with 16 nm spatial resolution.Voltage-clamped mouse ventricular myocytes were stretched by increasing the distance between patch pipette and a cell-attached stylus by 20%. After 2 min stretch, cells were shock-frozen for EPMA. Stretch incremented [Na] in peripheral cytosol from 23 to 48 mM, central cytosol from 17 to 29 mM, central mitochondria from 10 to 21 mM, nuclear envelope from 43 to 71 mM, nucleus from 12 to 24 mM. Stretch increased total [Ca] in peripheral cytosol from 570 to 840 muM, central cytosol from 404 to 840 muM. Mitochondrial [Ca] did not change. Stretch increased [Ca] in both nucleus (from 180 to 300 muM) and nuclear envelope (from 933 to 1530 muM) suggesting a calcium barrier function for the envelope.Block Of I-SAC by 50 muM streptomycin abolished stretch-induced increments in [Na] suggesting Na+ influx with I-SAC as underlying mechanism. Streptomycin abolished the stretch-induced increase in peripheral but not in central cytosolic [Ca], as if additional mechanisms to ISAC were involved in elevating central [Ca]. (C) 2003 Elsevier Science Ltd. All rights reserved.