Ocular perfusion pressure and color Doppler imaging of the external ophthalmic artery of rabbits treated with sildenafil citrate.

Ana Paula Araujo Costa,Luiz Henrique Da Silva,Naida Cristina Borges,Rosângela De Oliveira Alves Carvalho,Aline Maria Vasconcelos Lima,Andréia Vitor Couto Do Amaral

doi:10.1186/s12917-016-0778-5

Ana Paula Araujo Costa, Luiz Henrique Da Silva + Show 4 more

Open Access

https://doi.org/10.1186/s12917-016-0778-5

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Abstract

BackgroundIt has been proposed that sildenafil citrate can increase ocular blood flow, and that this property can be used to treat ocular disorders that involve reflex vasoconstriction. This study therefore proposes to ascertain the vasodilator effect of the drug on retrobulbar circulation in healthy rabbits. For this matter rabbits treated with sildenafil citrate or saline solution had their intraocular pressure (IOP), mean arterial pressure (MAP), ocular perfusion pressure (OPP) and color Doppler imaging of the external ophthalmic artery measured prior to treatment and on days one (moment M1), seven (when M2), fourteen (moment M3), twenty-one (moment M4), and thirty (moment M5) of treatment.ResultsThe MAP and OPP values of treated group were lower than those of control group at all times, and the mean values differed statistically at moments M1 (S = 71.52 mmHg, C = 84.76 mmHg, p = 0.0356) and M5 (S = 71.38 mmHg, C = 85.52 mmHg, p = 0.0252). The IOP and color Doppler values of the external ophthalmic artery did not differ between tested groups.ConclusionsThe dose of 10 mg of sildenafil citrate administered to healthy rabbits causes systemic vasodilation and consequently lower values of MAP and OPP. However, it does not induce changes in IOP and retrobulbar hemodynamics identifiable by color Doppler assessment of the external ophthalmic artery.

Highlights

It has been proposed that sildenafil citrate can increase ocular blood flow, and that this property can be used to treat ocular disorders that involve reflex vasoconstriction
Sildenafil citrate was the first phosphodiesterase type 5 (PDE-5) inhibitor to be approved for treatment of erectile dysfunction, and has become one of the world’s most widely prescribed drugs
Considering the potential of sildenafil citrate for treatment of ocular conditions with reflex vasoconstriction, the purpose of this study was to determine whether the drug has a vasodilator effect on retrobulbar circulation in healthy rabbits, based on an assessment of ocular perfusion pressure and on color Doppler imaging of the external ophthalmic artery

Summary

Introduction

It has been proposed that sildenafil citrate can increase ocular blood flow, and that this property can be used to treat ocular disorders that involve reflex vasoconstriction. Sildenafil citrate was the first phosphodiesterase type 5 (PDE-5) inhibitor to be approved for treatment of erectile dysfunction, and has become one of the world’s most widely prescribed drugs This drug inhibits PDE5, enzyme that hydrolyzes cyclic guanosine monophosphate (cGMP), regulating the circulating levels of cGMP, which in turn causes the corpus cavernosum muscles to relax and local blood flow to increase [1, 2]. The drug is widely used for treatment of erectile dysfunction, some users exhibited ocular side effects such as blurred vision and increased sensitivity to light These symptoms are associated with cross-inhibition of the drug with phosphodiesterase type 6 that is present in the retina, which participates in the regulation of the phototransduction mechanism. No consensus has yet been reached about the effects of sildenafil citrate

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