Molecular mechanisms underlying the corneal endothelial pump

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• 作者：Joseph A. Bonanno ; ^{jbonanno@indiana.edu}
• 关键词：corneal endothelium ; transparency ; ion & fluid transport
• 刊名：Experimental Eye Research
• 出版年：2012
• 出版时间：February 2012
• 年：2012
• 卷：95
• 期：1
• 页码：2-7
• 全文大小：346 K

文摘

The corneal endothelium is responsible for maintaining the hydration of the cornea. This is through a ¡°Pump-Leak?mechanism where the active transport properties of the endothelium represent the ¡°Pump?and the stromal swelling pressure represents the ¡°Leak? For the ¡°Pump? Na⁺, K⁺ ATPase activity and the presence of HCO₃^{?/sup>, Cl?/sup>, and carbonic anhydrase activity are required. Several basolateral (stromal side) anion transporters, apical (facing the aqueous humor) ion channels and water channels have been identified that could support a model for ion secretion as the basis for the endothelial pump, however evidence of sustained anion fluxes, osmotic gradients or the need for water channels is lacking. This has prompted consideration of other models, such as Electro-osmosis, and consideration of metabolite flux as components of the endothelial pump. Although the conditions under which the ¡°Pump?is supported are known, a complete model of the endothelial ¡°Pump?has yet to emerge.}