Changes in brain cell shape create residual extracellular space volume and explain tortuosity behavior during osmotic challenge

被引:111
作者
Chen, KC [1 ]
Nicholson, C [1 ]
机构
[1] NYU, Sch Med, Dept Physiol & Neurosci, New York, NY 10016 USA
关键词
diffusion; lattice; volume transmission; cell swelling and shrinkage; numerical simulation;
D O I
10.1073/pnas.150338197
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Diffusion of molecules in brain extracellular space is constrained by two macroscopic parameters, tortuosity factor lambda and volume fraction a. Recent studies in brain slices show that when osmolarity is reduced, lambda increases while alpha decreases. In contrast, with increased osmolarity. alpha increases, but lambda attains a plateau. Using homogenization theory and a variety of lattice models, we found that the plateau behavior of lambda can be explained if the shape of brain cells changes nonuniformly during the shrinking or swelling induced by osmotic challenge. The nonuniform cellular shrinkage creates residual extracellular space that temporarily traps diffusing molecules, thus impeding the macroscopic: diffusion. The paper also discusses the definition of tortuosity and its independence of the measurement frame of reference.
引用
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页码:8306 / 8311
页数:6
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