Mechanosensitive Calcium Entry and Mobilization in Renal A6 Cells
Mechanosensitive Calcium Entry and Mobilization in Renal A6 Cells
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DOI：
10.1007/s002329900495
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发表时间：
1999-03
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影响因子：
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通讯作者：
V. Urbach;I. Leguen;I. O'kelly;B. Harvey
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文献类型：
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作者：
V. Urbach;I. Leguen;I. O'kelly;B. Harvey
利用fura-2负载肾A6细胞的荧光成像，我们研究了渗透休克和局部膜拉伸时胞质Ca2+信号的产生。在低渗暴露下，细胞在短暂的[Ca2+]增加之前开始肿胀，并且在[Ca2+]恢复到基础水平后细胞仍然肿胀。暴露于2/3强度的林格下，细胞体积在3分钟内增加，随后缓慢的调节体积减少（RVD）。低渗刺激在延迟22秒后也产生了[Ca2+]的短暂增加。RVD和[Ca2+]对低渗的反应在无Ca2+的沐浴液和拉伸激活通道抑制剂钆（10 μm）中都被抑制。通过在细胞附着的贴片移液器内施加大气压（- 2kpa）拉伸膜，诱导低渗休克后[Ca2+]离子的类似全局增加。在无Ca2+的洗浴液中也观察到拉伸敏感的[Ca2+]增加，前提是贴片移液管含有Ca2+。机械敏感性[Ca2+]反应是通过钆（10 μm）或无Ca2+的移液管溶液，即使在Ca2+(2mm)存在于浴液中。用thapsigargin对细胞进行长期（bb0 ~ 10min）预处理可抑制[Ca2+]i对低渗的反应。这些结果提供了细胞肿胀或机械刺激可以激活与细胞内Ca2+释放机制相关的强大放大系统的证据。
Using spectrofluorescence imaging of fura-2 loaded renal A6 cells, we have investigated the generation of the cytosolic Ca2+signal in response to osmotic shock and localized membrane stretch. Upon hypotonic exposure, the cells began to swell prior to a transient increase in [Ca2+]iand the cells remained swollen after [Ca2+]ihad returned towards basal levels. Exposure to 2/3rd strength Ringer produced a cell volume increase within 3 min, followed by a slow regulatory volume decrease (RVD). The hypotonic challenge also produced a transient increase in [Ca2+] after a delay of 22 sec. Both the RVD and [Ca2+]iresponse to hypotonicity were inhibited in a Ca2+-free bathing solution and by gadolinium (10 μm), an inhibitor of stretch-activated channels. Stretching the membrane by application of subatmospheric pressure (-2 kPa) inside a cell-attached patch-pipette induced a similar global increase in [Ca2+]ias occurred after hypotonic shock. A stretch-sensitive [Ca2+]iincrease was also observed in a Ca2+-free bathing solution, provided the patch-pipette contained Ca2+. The mechanosensitive [Ca2+]iresponse was by gadolinium (10 μm) or Ca2+-free pipette solutions, even when Ca2+(2 mm) was present in the bath. Long-term (>10 min) pretreatment of the cells with thapsigargin inhibited the [Ca2+]iresponse to hypotonicity. These results provide evidence that cell swelling or mechanical stimulation can activate a powerful amplification system linked to intracellular Ca2+release mechanisms.