Theophylline effects on normal uveal melanocytes in culture: an ultrastructural study

Theophylline enhances maturation and differentiation of uveal melanocytes. By electron microscopy, we showed that theophylline changes small, dendritic melanocytes into large, platelike cells; it also enhances DOPA reaction as evidenced by increased deposition of DOPA reaction products in dilated cisternae and vesicles around the Golgi region. The effect is partially reversible in choroidal melanocytes but irreversible in iridial cells. It appears that theophylline, in addition to inducing tyrosine activity, accelerates the maturation and/or aging that normally occurs in cultured melanocytes when incubation is prolonged.