Regulation of cell-volume and cytoplasmic content of solutes by CFTR Cl Channel in cardiac cells

CFTR Cl 通道对心脏细胞中细胞体积和细胞质溶质含量的调节

• 批准号: 11670046
• 负责人: EHARA Tsuguhisa
• 金额: $ 2.3万
• 依托单位: Saga Medical School
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670046/
• 关键词: chloride channel; CFTR; cardiac cell; cell-volume regulation; furosemide; Na-K-2Cl cotransporter; bumetanide; K-Cl cotransporter; アドレナリン; cyclic AMP

1. Role of CFTR Cl current in volume regulation in cardiac cellsThe effects of activation of cyclic AMP-dependent Cl^- current (I_<Cl, cAMP>) on cell volume were studied at various [K^+]_O under isosmotic conditions in guinea-pig ventricular myocytes. The area of the cell image obtained with videomicroscopy was used as an index of cell volume. I_<Cl, cAMP> was activated by adrenaline (5.5 μM). At 5.4 mM [K^+]_O with low [Cl^-]_O, where V_m was negative to the predicted equilibrium potential of Cl^- (E_<Cl>), adrenaline decreased the cell area sizably. At high [K^+]_O with normal [Cl^-]_O, where V_m was positive to E_<Cl>, adrenaline increased the cell area ; at 145.4 mM [K^+]_O the cell area was increased to about 110% of control. Addition of BaCl_2 (1mM), a blocker of K^+ channels, attenuated the adrenaline-dependent cell swelling, supporting the view that Cl^- fluxes must be accompanied by co-fluxes of K^+ ions, to affect the cell volume. The results show that activation of I_<Cl, cA … More MP> can shrink or inflate the cardiac cells under isosmotic conditions, depending on V_m and E_<Cl>2. Role of Na-K-2Cl and K-Cl cotransporters in volume regulation in cardiac cellsApplication of Na-deficient or Cl-deficient solution to the cell induced a decrease in cell volume. A similar cell-shrinkage was induced also by application of bumetanide (10μM) or furosemide (2mM), and in the presence of these diuretics, Na-removal was without effect on cell volume. These results are consistent with the view that Na-K-2Cl cotransporter (NKCC), that is sensitive to the diuretics, plays a role in cell-volume regulation in cardiac cells. However, Cl-removal in the presence of bumetanide (10μM) induced a cell shrinkage. This bumetanide-insensitive, Cl-dependent cell shrinkage was found to be K-dependent, Na-independent, and furosemide-sensitive. These findings can be explained by assuming that K-Cl cotransporter (KCC) activates in low-Cl or low-K solution, thereby affecting the cell volume, that 10μM bumetanide does not inhibit KCC, and that 2 mM furosemide does inhibit it. Our results show that both NKCC and KCC play a role in cell-volume regulation in cardiac cells. Less

1.CFTRCl电流在心肌细胞容量调节中的作用研究在不同[K~+]_O等渗条件下，激活依赖于cAMP的cAMP氯电流(I_&lt；Cl，cAMP&gt_1)对心肌细胞容量的影响。用视频显微镜获得的细胞图像的面积作为细胞体积的指标。肾上腺素(5.5μM)可激活I&lt；Cl，cAMP&gt；当[K^+]O浓度为5.4 mM时，当[Cl^-]O较低时，Vm与预测的平衡电位(E&lt；Cl&gt；)呈负值时，肾上腺素使细胞面积显著减小。在高[K^+]_O和正常[C l^-]_O时，肾上腺素增加了细胞面积，当[K^+]_O为145.4 mM时，细胞面积增加到对照的110%左右。加入K~(+)通道阻断剂BaCl2(1 MM)可减轻肾上腺素依赖的细胞肿胀，支持氯离子通量必须伴随K~(++)离子共通量才能影响细胞体积的观点。结果表明，I&lt；Cl，CA…的活化在等渗条件下，更多的MP&gt；可使心肌细胞收缩或膨胀，这取决于V_m和E&lt；Cl&gt；2.Na-K-2Cl和K-Cl共转运体在心肌细胞容量调节中的作用缺钠或缺氯溶液可引起细胞体积的减少。应用布美他尼(10μM)或速尿(2 MM)也可引起类似的细胞收缩，在这些利尿剂存在的情况下，去钠对细胞体积没有影响。这些结果与对利尿剂敏感的Na-K-2Cl协转运体(NKCC)在心肌细胞容量调节中的作用的观点一致。然而，在布美他尼(10μM)存在的情况下，除氯导致细胞收缩。这种布美他尼不敏感，氯依赖的细胞收缩被发现是K依赖的，Na不依赖的，速尿敏感的。这些发现可以通过假设K-Cl协同转运体(Kcc)在低氯或低K溶液中被激活从而影响细胞体积，10μM布美塔尼不抑制Kcc，以及2 mM速尿抑制Kcc来解释。我们的结果表明，NKCC和KCC都在心肌细胞的细胞体积调节中发挥作用。较少

项目成果

Yamamoto,S.: "Changes in cell volume induced by activation of the cyclic AMP-dependent channel in guinea-pig cardiac myocytes"Jpn.J.Physiol.. 51. 31-41 (2001)

Yamamoto,S.：“豚鼠心肌细胞中循环 AMP 依赖性通道的激活引起的细胞体积变化”Jpn.J.Physiol.. 51. 31-41 (2001)

Yamamoto,S.: "Image analysis revealed that a movement of K^+ and Cl^- through ion channels change the cell volume of single cells"Jpn.J.Physiol.. 49(Suppl) (in press). (1999)

Yamamoto,S.：“图像分析表明 K^ 和 Cl^- 通过离子通道的运动会改变单个细胞的细胞体积”Jpn.J.Physiol.. 49（增刊）（印刷中）。