Characterization of Biological Membranes by Equivalent Pores
Characterization of Biological Membranes by Equivalent Pores
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通过等效孔表征生物膜
DOI：
10.1085/jgp.51.5.335
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发表时间：
1968
期刊：
影响因子：
--
通讯作者：
A. K. Solomon
中科院分区：
文献类型：
--
作者：
A. K. Solomon
根据脂不溶性和脂=溶性分子的平行途径描述生物膜的渗透性特性，其根源在于Overton（1）和Collander和Barlund（2）的研究，并已在几本书中详细介绍，如Davson和Danielli（3）和H6 ber（4）。等效孔的概念是对脂不溶性分子所走路径的描述，它源于Koefoed-Johnsen和Ussing（5）以及Pappenheimer、Renkin和Borrero（6）的处理，并被所罗门及其同事（7-11）用于表征单细胞膜，特别是红细胞膜的行为。基于不可逆热力学的更强有力的数学处理已被应用于生物系统，并且从生物系统和有机膜中获得了与等效孔概念有关的新的实验证据。因此，似乎有必要重新审视等效孔概念的理论基础和适用于单一生物膜时对其有效性的证据。由于大量的讨论将与扩散有关，因此理解这一过程的本质是很重要的，这一过程可能是爱因斯坦（12）最好的描述：“热的分子理论提供了一个。. .从这个角度来看，扩散过程可以考虑。我们认为是不规则运动的过程。.物质的内含物将以这样一种方式起作用，即液体的单个分子将以最不规则的方式改变它们的位置。溶质分子的这种游离在某种程度上是偶然的，其结果是，溶质浓度原来的不均匀分布将逐渐被均匀分布所取代。扩散可以与粘性或整体流动形成对比，在粘性或整体流动中，液体中的许多分子响应于物理力（通常是压力梯度）而一起移动。考虑到流体的相邻部分之间的吸引力。正如Prandtl和Tietjens（13）指出的那样，“在均匀流体中，单个流体粒子的行为并不特别令人感兴趣;人们只想知道每一点的运动状态及其随时间的变化。Onsager（14）非常简洁地阐述了这一问题，他说：“粘性流是液体相邻部分的相对运动。扩散是其组分的相对运动。“当溶剂通过膜只能通过膜中分子的溶解来进行时，溶剂运输仅通过扩散来进行。当压力梯度施加在直径比管道大几个数量级的管道上时，
The description of the permeability properties of biological membranes in terms of parallel pathways for lipid-insoluble and lipid=soluble molecules has its roots in the studies of Overton (1) and Collander and Barlund (2) and has been presented in detail in several books, such as those of Davson and Danielli (3) and H6ber (4). The concept of the equivalent pore as a description of the path taken by lipid-insoluble molecules grew from the treatments of Koefoed-Johnsen and Ussing (5) and Pappenheimer, Renkin, and Borrero (6) and has been used by Solomon and coworkers (7-11) to characterize the behavior of single cell membranes, particularly those of red cells. More powerful mathematical treatments based on irreversible thermodynamics have been applied to biological systems, and new experimental evidence bearing on the equivalent pore concept has been obtained both from biological systems and from organic membranes. It appears desirable, therefore, to reexamine both the theoretical basis for the equivalent pore concept and the evidence bearing on its validity when applied to single biological membranes. Since a great deal of the discussion will be concerned with diffusion, it is important to understand the nature of this process, which was perhaps best described by Einstein (12) : " the molecular theory of heat affords a . . . point of view from which the process of diffusion can be considered. The process of irregular motion which we have considered as the h e a t . . , content of a substance will operate in such a manner that the single molecules of a liquid will alter their positions in the most irregular manner thinkable. This wandering about of the molecules of the solute--fortuitous to a certain extent--will have as a result that the original non-uniform distribution of concentration of the solute will gradually give place to a uniform one." Diffusion may be contrasted with viscous or bulk flow, in which a number of molecules in a liquid move together in response to a physical force, often a pressure gradient. Account is taken of the attractive forces between neighboring portions of the fluid. As Prandtl and Tietjens (13) point out, " in homogeneous fluids the behavior of individual fluid particles is not of particular interest; one only wants to know the state of motion and its alteration with time at every point." The matter was put very succinctly by Onsager (14), who stated: "viscous flow is a relative motion of adjacent portions of a liquid. Diffusion is a relative motion of its constituents." When solvent passage through a membrane can take place only by dissolution of the molecules in the membrane, solvent transport takes place by diffusion alone. When a pressure gradient is imposed across a pipe whose diameter is greater by orders