Permeability Properties of the Ciliary Epithelium in Response to Prostaglandins

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Abstract

The effects of prostaglandins E₁, E₂, and F_2a were studied on both transport and flow conductivity in isolated rabbit ciliary body. All prostaglandins caused an increase in active transport and flow conductivity; the dose-dependency of these responses differed greatly, since transport was unaffected until concentrations of E₁ and E₂ were 10 µg per milliliter, whereas flow conductivity was increased at concentrations of 0.1 µg per milliliter; F_2a increased flow conductivity at a concentration of 1.0 µg per milliliter and transport at 10 µg per milliliter. The descending order of potency in their ability to increase transport and flow conductivity was E₁ ≃ E₂ > F_2a. Prior treatment of the tissues with polyphloretin phosphate prevented any prostaglandin response, but did not block the response once initiated. The results suggest that the increased permeability of the ciliary epithelium is the major factor in causing an increase in intraocular pressure seen after prostaglandin.