Beta adrenergic effects on ciliary epithelial permeability, aqueous humor formation and pseudofacility in the normal and sympathectomized rabbit eye

Abstract

Relatively selective beta 1- and beta 2-adrenergic agonists (tazolol and terbutaline) and antagonists (metoprolol and butoxamine) were topically applied to albino rabbit eyes and to isolated ciliary epithelium. The beta 2-agonist, terbutaline, was the most effective agent in reducing intraocular pressure although all compounds induced changes in aqueous humor formation rate and pseudofacility. The effects on the isolated ciliary epithelium were determined on tissues derived from both normal and superior cervical ganglionectomized eyes. The beta 1- and beta 2-agonists as well as the beta 1-antagonist induced large permeability increases while the beta 2-antagonist induced a small permeability increase in normal tissues. In ganglionectomized tissues the beta 1-antagonist effect was decreased and the beta 2-antagonist effect enhanced while the agonist effects were almost unchanged. The results show that both beta 1- and beta 2-receptors exist in the ciliary epithelium and that stimulation of either receptor leads to an increase in fluid permeability and alterations in aqueous dynamics.