Farahbakhsh N A, Fain G L
Invest Ophthalmol Vis Sci. 1987 Jun;28(6):934-44.
We describe a new method for investigating ion and water transport in ciliary epithelium. A single ciliary process from the rabbit is isolated, placed in a chamber, and rapidly perfused with physiological Ringer. If this process is then viewed at its edge with a light microscope using Hoffman modulation contrast optics, it is possible to record the image of a single layer of non-pigmented epithelial cells. When these cells are exposed to hypotonic Ringer, they swell and then reduce their volume by extruding salt and water. We have used the rate of swelling to calculate the hydraulic conductivity of the non-pigmented cells. These measurements show that the aqueous humor could be secreted by the generation of a modest osmotic gradient across the non-pigmented cell basal membrane. We have also used this preparation to investigate the mechanism of the decrease in cell volume after swelling in hypotonic medium. This volume regulatory decrease can occur at a rate as large as the rate of normal fluid transport during the secretion of the aqueous. It appears to be caused in part by active Na extrusion, since it is partially inhibited by exposure to ouabain. In addition, there appears also to be a contribution to the regulatory response from a swelling-induced K efflux, since the rate of volume regulation can be altered by perfusion with Ba2+ and by changing the extracellular K concentration.
我们描述了一种研究睫状体上皮中离子和水转运的新方法。从兔子身上分离出单个睫状突，将其置于一个腔室中，并用生理林格液快速灌注。如果随后使用霍夫曼调制对比光学显微镜在其边缘观察这个睫状突，就有可能记录单层无色素上皮细胞的图像。当这些细胞暴露于低渗林格液时，它们会肿胀，然后通过排出盐分和水分来减小体积。我们利用肿胀速率来计算无色素细胞的水导率。这些测量结果表明，房水可能是通过在无色素细胞基底膜上产生适度的渗透梯度而分泌的。我们还利用这种制备方法来研究低渗介质中细胞肿胀后体积减小的机制。这种体积调节性减小的速率可能与房水分泌过程中正常液体转运的速率一样大。它似乎部分是由主动钠排出引起的，因为暴露于哇巴因会部分抑制它。此外，肿胀诱导的钾外流似乎也对调节反应有贡献，因为通过用 Ba2+ 灌注和改变细胞外钾浓度可以改变体积调节的速率。
