We will investigate the effects of cyclic nucleotides and related compounds on aqueous humor dynamics in the rabbit and monkey. Experiments will include the measuring of intraocular pressure and outflow facility. We will try to demonstrate the mechanism of action by which cyclic AMP increases outflow. We will attempt to identify the site of action of catecholamines by localizing the alpha-receptors and beta-receptors in ocular tissues as well as histochemical localization of cyclic AMP. BIBLIOGRAPHIC REFERENCES: Kass, M.A., Reid, T.W., Neufeld, A.H., Bausher, L.P. and Sears, M.L.: The effect of d-isoproterenol on intraocular pressure of the rabbit, monkey, and man. Invest. Ophthal. 15:113, 1976. Neufeld, A.H.: The regulation of intraocular pressure by cyclic AMP. Acta of the IX World Conference of the European Microcirculation Society, 1976, in press.