The Reaction of Uveal Pigment in vitro with Polycyclic Compounds

¹ Section of Ophthalmology, Department of Surgery, the University of Chicago, Chicago, Ill.

It was previously found that phenothiazine drugs accumulate in the uveal tract of pigmented experimental animals and not in albino animals. The present work demonstrates that even higher concentrations of phenothiazines can he taken up by uveal pigment granules in vitro. Further, this property is shared by a number of polycyclic aromatic compounds, particularly those which have coplanar fused rings. Uptake is shown by pigment granules from the choroid, iris, ciliary body, and retinal pigment epithelium. In addition, synthetic melanin made by the oxidation of dihydroxyphenylalanine is highly active in removing polycyclic compounds from aqueous solution. This phenomenon is believed to be a type of adsorption in which the forces may well be due to charge transfer reaction--the melanin being the electron acceptor. The reaction may have considerable significance in the mechanism of action of retinotoxic and choroidotoxic substances.