Hypotensive effect of UDP on intraocular pressure in rabbits

Nucleotides can modify intraocular pressure (IOP). We have tested the ability of uridine-5′-diphosphate, UDP, for modulating IOP in New Zealand white rabbits. Uridine 5′ diphosphate, UDP, reduced IOP by 82.9 ± 2.6% compared to control. Dose-response analysis demonstrated a concentration dependent pattern which presented a pD2 value of 7.57 ± 1.45, equivalent to an EC50 of 26.91 nM. Of all the tested P2 receptor antagonists, suramin, pyridoxalphosphate-6-azophenyl-2, 4-disulfonic acid (PPADS) and Reactive Blue 2 (RB-2), only the last two were able to reverse the action triggered by UDP. Altogether, UDP acting probably on P2Y6 receptors present on the ciliary processes, can reduce intraocular pressure, indicating that this substance may be used for the treatment of ocular hypertension and glaucoma.