Localisation of prostaglandin F(2α) and E₂ binding sites in the human eye

Prostaglandin F(2α) reduces intraocular pressure possibly by increasing uveoscleral outflow. To further understand the mechanism of its action binding sites for prostaglandin F(2α) and, for comparison, prostaglandin E₂ were localised in sections of human cadaveric eyes using an in vitro ligand-binding technique and autoradiography. Specific binding sites for both prostaglandin F(2α) and E₂ were co-localised at a high level in the areas of the ciliary muscles and iris sphincter muscles, and at a lower level in the iris epithelium and the retina. The results suggest that prostaglandin F(2α) and also prostaglandin E₂, could modulate uveoscleral outflow by binding to their receptors located on the ciliary muscles and inducing their relaxation.