Aquaporins and Water Transport in the Cornea
The eye contains specialized avascular tissues for corneal and lens transparency, secretory epithelia for regulation of aqueous fluid volume and pressure, and electrically excitable cells for retinal signal transduction. Regulated fluid transport between extravascular spaces and adjacent tissues or microvessels supports these specialized functions. The general paradigm in mammalian tissues, including the eye, is that water movement follows osmotic gradients generated by active and secondary active solute transport. Although all cell membranes have significant water permeability, AQP-type water cells are found in some cell types where they increase plasma membrane water permeability by a few up to approximately 100-fold compared to membranes without AQPs. This chapter provides a brief description of AQP structure and function, followed by evidence about the physiological role of AQPs in extraocular and ocular tissues, with focus on cornea.
Aquaporin Structure and Transport...
KeywordsWater Permeability Ocular Surface Corneal Endothelium Corneal Epithelial Cell Ciliary Epithelium
Supported by grants EY13574, HL73856, DK72517, DK35124, HL59198, and EB00415 from the National Institutes of Health, and drug discovery and research development program grants from the Cystic Fibrosis Foundation.
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