Surface:volume relationship in cardiac myocytes studied with confocal microscopy and membrane capacitance measurements: Species-dependence and developmental effects
Surface:volume relationship in cardiac myocytes studied with confocal microscopy and membrane capacitance measurements: Species-dependence and developmental effects
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DOI：
10.1016/s0006-3495(96)79711-4
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发表时间：
1996-03-01
影响因子：
3.4
通讯作者：
Bers, DM
中科院分区：
文献类型：
--
作者：
Satoh, H;Delbridge, LMD;Bers, DM
通过膜通道的离子通量对细胞内离子浓度变化的贡献的定量分析将受益于对细胞体积的准确了解。它将允许离子电流测量与单个细胞中离子浓度的同时测量直接相关。由于常规光学显微镜的各种局限性，缺乏一种准确测定细胞体积的简单方法。我们将荧光激光扫描共聚焦显微镜的光学切片能力与全细胞膜片钳技术相结合，研究了细胞体积与膜电容的关系。用荧光染料钙黄绿素对单个心肌细胞进行光学切片，以产生一系列共聚焦图像。通过共聚焦图像的三维体积绘制，确定了三种不同哺乳动物的心肌细胞的体积。细胞体积兔(n=28)为30.4+/-7.3pl(平均+/-SD)，雪貂(n=23)为30.9+/-9.0pl，大鼠(n=21)为34.4+/-7.0pl。各种动物的膜电容与细胞体积呈线性正相关。不同物种的电容体积比有显著差异(兔为4.58+/-0.45pF/pl，雪貂为5.39+/-0.57pF/pl，大鼠为8.44+/-1.35pF/pl)。此外，电容-体积比与发育阶段有关(6月龄大鼠为8.88+/-1.14pF/pl，3月龄大鼠为6.76+/-0.62pF/pl)。这些数据表明，心肌细胞的表面积与体积的比率经历了显著的发育变化，并且在不同的哺乳动物之间存在差异。我们进一步证实，细胞膜电容或细胞长度和宽度的乘积的容易测量的参数为单个细胞的体积提供了可靠的、但依赖于物种的估计。
The quantitative analysis of the contribution of ion fluxes through membrane channels to changes of intracellular ion concentrations would benefit from the exact knowledge of the cell volume. It would allow direct correlation of ionic current measurements with simultaneous measurements of ion concentrations in individual cells. Because of various limitations of conventional light microscopy a simple method for accurate cell volume determination is lacking. We have combined the optical sectioning capabilities of fluorescence laser scanning confocal microscopy and the whole-cell patch-clamp technique to study the correlation between cell volume and membrane capacitance. Single cardiac myocytes loaded with the fluorescent dye calcein were optically sectioned to produce a series of confocal images. The volume of cardiac myocytes of three different mammalian species was determined by three-dimensional volume rendering of the confocal images. The calculated cell volumes were 30.4 +/- 7.3 pl (mean +/- SD) in rabbits (n = 28), 30.9 +/- 9.0 pl in ferrets (n = 23), and 34.4 +/- 7.0 pl in rats (n = 21), respectively. There was a positive linear correlation between membrane capacitance and cell volume in each animal species. The capacitance-volume ratios were significantly different among species (4.58 +/- 0.45 pF/pl in rabbit, 5.39 +/- 0.57 pF/pl in ferret, and 8.44 +/- 1.35 pF/pl in rat). Furthermore, the capacitance-volume ratio was dependent on the developmental stage (8.88 +/- 1.14 pF/pl in 6-month-old rats versus 6.76 +/- 0.62 pF/pl in 3-month-old rats). The data suggest that the ratio of surface area:volume of cardiac myocytes undergoes significant developmental changes and differs among mammalian species. We further established that the easily measurable parameters of cell membrane capacitance or the product of cell length and width provide reliable but species-dependent estimates for the volume of individual cells.