The influx of tritium-labeled water from the blood to the intraocular fluids

Abstract

A new experimental approach to the study of the blood-vitreous body barrier is presented. At various times after administering 3H-labeled water to the animal its eyes were excised and were divested of cornea and sclera and sectioned into slices (< 1 mm thick) cut perpendicular to the optic axis. Profile plots ( 3H/slice vs. distance along optic axis) were analyzed. Plateau regions of the profile plots suggested a distribution of 3H-labeled water in a shell at the surface of the vitreous body. Changes in shape of the plots as time of the experiments increased suggested posteriorward flow of fluid from the posterior chamber into the vitreous body. By assuming that the amount of 3H-labeled water in a slice of the plateau region of a profile plot was equivalent to the amount which crossed that segment of vitreous body surface, kinetic analysis of data from normal animals and from anesthetized and/or anoxic animals was obtained. The rate constant calculated for the net transfer of 3H-labeled water from blood to vitreous body, was 3·10 × 10 −4/sec for normal animals and 10·21 × 10 −4/sec for animals made anoxic by succinyl choline or general anesthesia. Thus, even brief periods of anoxia appears to make the blood-vitreous body barrier more permeable to water in the inward direction.