QUANTITATIVE VIDEO MICROSCOPY OF PATCH CLAMPED MEMBRANES STRESS, STRAIN, CAPACITANCE, AND STRETCH CHANNEL ACTIVATION
QUANTITATIVE VIDEO MICROSCOPY OF PATCH CLAMPED MEMBRANES STRESS, STRAIN, CAPACITANCE, AND STRETCH CHANNEL ACTIVATION
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DOI：
10.1016/s0006-3495(91)82285-8
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发表时间：
1991-03-01
影响因子：
3.4
通讯作者：
JING, ZQ
中科院分区：
文献类型：
--
作者：
SOKABE, M;SACHS, F;JING, ZQ
通过对移液管施加受控的吸力或压力来拉伸来自鸡骨骼肌的膜贴片。 根据贴片的图像，通过图像与几何模型的非线性回归计算贴片尺寸（面积和曲率半径）。 在没有施加压力的情况下，贴片膜几乎是平面的并且垂直于移液管的壁。 随着压力梯度的增加，斑块凸起，曲率半径减小，面积增加。 贴片电容以0.7 μ F/cm 2的速率与面积的变化成精确比例地变化。 面积的增加是由于脂质（可能含有少量可扩散蛋白质）沿着移液管壁流入贴片。 随着压力梯度的松弛，流动是可逆的。 膜的面积弹性常数约为50 dyn/cm，对细胞松弛素B不敏感，可能代表了基础血影蛋白/肌营养不良蛋白网络的弹性。 同时测量的拉伸激活（SA）离子通道活性的补丁显示，从不同的补丁通道的灵敏度，虽然不同的计算时，作为施加的压力的函数，是相同的计算时，作为张力的函数。 由于斑块脂质自由流动，因此在稳态下无应力，SA通道必须通过细胞骨架中的张力激活。
Membrane patches from chick skeletal muscle were stretched by applying controlled suction or pressure to the pipette. From images of the patch, the patch dimensions (area and radius of curvature) were computed by nonlinear regression of the images to a geometric model. With no applied pressure, patch membranes are nearly planar and normal to the wall of the pipette. With increasing pressure gradients, the patch bulges, the radius of curvature decreases, and the area increases. The patch capacitance changes in exact proportion to the change in area at a rate of 0.7-mu-F/cm2. The increase in area is due to a flow of lipid (with perhaps small amounts of diffusible protein) along the walls of the pipette into the patch. The flow is reversible with a relaxation of the pressure gradient. The area elastic constant of the membrane is approximately 50 dyn/cm, insensitive to cytochalasin B and probably represents the elasticity of the underlying spectrin/dystrophin network. Simultaneous measurements of stretch activated (SA) ion channel activity in the patch showed that the sensitivity of channels from different patches, although different when calculated as a function of applied pressure, was the same when calculated as a function of tension. Because patch lipid is free to flow, and hence stress-free in the steady state, SA channels must be activated by tension in the cytoskeleton.