Effect of diinosine polyphosphates on intraocular pressure in normotensive rabbits

The ability of diinosine polyphosphates, diinosine triphosphate (Ip3I), diinosine tetraphosphate (Ip4I) and diinosine pentaphosphate (Ip5I) to modify intraocular pressure in normotensive New Zealand white rabbits was tested. Ip5I produced increase in intraocular pressure, while Ip3I and Ip4I produced a decrease. Ip4I was the most effective reducing intraocular pressure inducing a maximal decrease of intraocular pressure to 74.2 ± 2.5% compared with the control value. Dose–response analysis demonstrated a concentration dependent pattern which presented a pD2 value of 6.19 ± 0.18, equivalent to an EC50 of 0.63 μM. Regarding the underlying mechanism used by Ip4I to reduce intraocular pressure, studies with agonists and antagonists revealed that Ip4I reduces intraocular pressure via P2Y receptors in the eye. We suggest that topical application of Ip4I to the cornea has therapeutic potential for lowering intraocular pressure, a major risk factor for glaucoma.

► Diinosine polyphosphates modify IOP in New Zealand white rabbits.
► Ip5I increased IOP, while Ip3I and Ip4I produced a decrease.
► Ip4I reduces IOP and may be used for the treatment of ocular hypertension.