Ouabain and Aqueous Humor Dynamics in the Rabbit Eye.

This study was supported in part by Research Crane B-621 from the National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Md. all experiments. Ouabain was given intravenously in doses of 100 to 250 meg. per kilogram or by injection into the vitreous of one eye (0.1 meg. ouabain in 10 to 20 meg. of distilled water), lntravitreal injections were performed with a No. 705 Hamilton Microliter Syringe by methods previously described. Tonography was carried out with an electronic tonometer connected to a Leeds and Northrup recorder. Values were interpreted from the tables of Wistrand. All tonography was performed with the animals under topical tetracaine 0.5 per cent anesthesia without the use of general anesthetic agents. The rate of aqueous flow was estimated from F = C (Po P») where F equals rate ot aqueous flow (jul/min.), C equals outflow facility (/ul/min./mm. Hg), Po equals intraocular pressure (mm. Hg), and Pv equals episcleral venous pressure (mm. Hg). Blood was obtained by cardiac puncture with a heparinized syringe. Posterior and anterior chamber fluids were drawn from proptosed eyes into calibrated pipettes. Total carbon dioxide content was determined by the method of Van Slyke. Ascorbic acid was titrated in 4 per cent metaphosphoric acid with dichlorphenol-indophenol. In order to obtain an elevated and reasonably stable blood level of ascorbate of approximately 10 mg. per cent, rabbits were injected subcutaneously with 200 mg. per kilogram sodium ascorbate 16 hours prior to the posterior and