ARTICLE

STUDIES ON THE CORNEA

Gordon I. Kaye Ph.D.¹ and George D. Pappas Ph.D.¹

¹ From the Department of Anatomy, College of Physicians and Surgeons, Columbia University New York

Physiological studies have demonstrated that ions, as well as large molecules such as hemoglobin or fluorescein, can diffuse across and within the cornea. Most of the substrates for corneal metabolism are obtained from aqueous humor filling the anterior chamber. In order to receive its nutrients and in order to maintain its normal conditions of hydration, the avascular cornea must transport relatively large amounts of solute and solvent across the cellular layers which cover this structure. It has been suggested in the past that there may be a morphological basis for the transport of large amounts of solvents and solutes by cells by the mechanism of pinocytosis. The use of electron-opaque markers to study fluid movements at the electron microscope magnification level was described by Wissig (29). The present study describes the fine structure of the normal rabbit cornea and the pathways of transport of colloidal particles by the cornea in vivo. Rabbit corneas were exposed in vivo to suspensions of saccharated iron oxide, thorium dioxide, or ferritin by injection of the material into the anterior chamber. In other experiments thorium dioxide or saccharated iron oxide was injected into the corneal stroma, producing a small bleb. Particles presented at the aqueous humor surface of the rabbit corneal endothelium are first attached to the cell surface and then pinocytosed. It appears that the particles are carried around the terminal bar by an intracellular pathway involving the pinocytosis of the particles and their subsequent transport in vesicles to the lateral cell margin basal to the terminal bar. Particles introduced at the basal surface of the endothelium (via blebs in the corneal stroma) are apparently carried through the endothelial cells in membrane-bounded vesicles without appearing in the intercellular space. There appears to be free diffusion of these particles through Descemet's membrane and the corneal stroma. The stromal cells take up large quantities of the particles when blebs are injected into the stroma.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

• Castro-Munozledo, F (1994). Development of a spontaneous permanent cell line of rabbit corneal epithelial cells that undergoes sequential stages of differentiation in cell culture. J. Cell Sci. 107: 2343-2351 [Abstract]  
• Harris, J. E. (1967). Current Thoughts on the Maintenance of Corneal Hydration in Vivo. Arch Ophthalmol 78: 126-132 [Abstract]  
• DONN, A. (1966). Cornea and Sclera. Arch Ophthalmol 75: 261-288  
• Kaye, G. I., Cole, J. D., Donn, A. (1965). Electron Microscopy: Sodium Localization in Normal and Ouabain-Treated Transporting Cells. Science 150: 1167-1168 [Abstract]  
• DOHLMAN, C. H. (1963). Cornea and Sclera. Arch Ophthalmol 69: 257-278  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents