Cat Heart Muscle in Vitro
Cat Heart Muscle in Vitro
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体外猫心脏肌肉
DOI：
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发表时间：
1964
期刊：
影响因子：
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通讯作者：
R. Bernstein
中科院分区：
文献类型：
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作者：
E. Page;R. Bernstein
对于蔗糖、SO4和Na的扩散，实验点符合平面片扩散方程的整个时间进程。胞外扩散通道的曲折因子λ对蔗糖为1.4 4±0.0 5(平均值±扫描电子显微镜)，对SO4和Na相近。在稳态扩散过程中，根据λ和线性渐近线的斜率计算出的胞外扩散的可用面积，对于无意义的物种(蔗糖、硫酸、钠)和有意的物种(水、尿素、甘油)来说，都是0.17-0.23。意思是分子表现出接近稳定状态的特征延长，在水的曲线上有一个无法解释的“驼峰”。用Fatt等人提出的模型解释了观测到的分子扩散的时间过程。用于在含有死端孔隙体积的线性多孔介质中扩散。大分子如菊粉和透析后的葡聚糖(直径150到180安)在薄片中扩散。这些分子可能具有反射系数σ>；0。蔗糖扩散通道所占肌肉水分的比例明显小于3小时。甘露醇、蔗糖和菊粉空隙。
The rate of transfer of labeled molecules across a sheet of quiescent cat right ventricle separating two chambers containing chemically identical solutions was followed at 23°C. For the diffusion of sucrose, SO4, and Na the experimental points fit the entire time course of the plot of the diffusion equation for a plane sheet. The tortuosity factor of the extracellular diffusion channel, λ was 1.44 ± 0.05 (mean ± SEM) for sucrose and similar for SO4 and Na. The fractional area available for extracellular diffusion, calculated from λ and the slope of the linear asymptote approached during steady state diffusion, was 0.17–0.23 for both impermeant species (sucrose, SO4, Na) and permeant species (water, urea, glycerol). Permeant molecules showed a characteristic prolongation of the approach to the steady state, with an unexplained "hump" in the curve for water. The observed time courses for diffusion of permeant molecules are interpreted in terms of a model proposed by Fatt et al. for diffusion through linear porous media containing dead-end pore volume. Large molecules like inulin and dialyzed dextran (diameter 150 to 180 A) diffuse through the sheet. These molecules may have a reflection coefficient σ > 0. The fraction of muscle water occupied by the sucrose diffusion channel is significantly smaller than the 3 hr. mannitol, sucrose, and inulin spaces.