EFFECTS OF FLOW-RATE ON PROXIMAL TUBULE ULTRASTRUCTURE
EFFECTS OF FLOW-RATE ON PROXIMAL TUBULE ULTRASTRUCTURE
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DOI：
10.1152/ajprenal.1987.253.3.f582
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发表时间：
1987-09-01
影响因子：
--
通讯作者：
STANTON, BA
中科院分区：
文献类型：
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作者：
MAUNSBACH, AB;GIEBISCH, GH;STANTON, BA
在这项研究中，我们研究了近端小管的超微结构在流体流动的变化，以确定是否以前观察到的溶质和水重吸收的变化可能与细胞超微结构的改变。在每个肾脏，两个近端小管（S2段）同时灌注在5和45 nl/min。随后，控制和实验小管的细胞超微结构进行了检查，结合形态学的电子显微镜。流速的变化极大地改变了肾小管上皮的几何形状。增强流动增加管腔直径和降低细胞高度。每平方微米管腔上皮表面积的微绒毛数量随着流速的增加而减少，从高流速时的对照值42.5减少到35.5。然而，每毫米小管长度的微绒毛总数没有变化。因此，微绒毛之间的距离取决于流速，估计为621、741和904埃。分别在低流量、对照和高流量小管中。我们认为，流速增加，可能是通过改变跨上皮流体静压梯度，导致微绒毛之间的距离增加和细胞超微结构的其他改变，可能有助于增加溶质和水的重吸收。
In this study we investigated the ultrastructure of the proximal tubule during alterations in fluid flow to determine whether preivously observed changes in solute and water reabsorption may be related to alterations in cell ultrastructure. In each kidney, two proximal tubules (S2 segments) were perfused simultaneously at 5 and 45 nl/min. Subsequently, cell ultrastructures of control and experimental tubules was examined by electron microscopy in combination with morphometry. Changes in flow rate greatly modified the geometry of the tubule epithelium. Enhanced flow increased luminal diameter and decreased cell height. The number of microvilli per square micrometer of luminal epithelial surface area decreased with increased flow rate from a control value of 42.5 to 35.5 at high flow. However, the total number of microvilli per millimeter tubule length did not change. Thus the distance between microvilli was dependent on flow rate and was estimated to be 621, 741, and 904 .ANG. in low flow, control, and high flow tubules, respectively. We suggest that increased flow rate, perhaps by altering transepithelial hydrostatic pressure gradients, leads to an icnrease in the distance between the microvilli and to other alterations in cellular ultrastructures that may contribute to the augmentation of solute and water reabsorption.