Sildenafil alters retinal function in mouse carriers of Retinitis Pigmentosa

Abstract

Sildenafil, the active ingredient in Viagra®, has been reported to cause transient visual disturbance from inhibition of phosphodiesterase 6 (PDE6), a key enzyme in the visual phototransduction pathway. This study investigated the effects of sildenafil on the rd1+/- mouse, a model for carriers of Retinitis Pigmentosa which exhibit normal vision but may have a lower threshold for cellular stress caused by sildenafil due to a heterozygous mutation in PDE6. Sildenafil caused a dose-dependent decrease in electroretinogram (ERG) responses of normal mice which mostly recovered two days post administration. In contrast, rd1+/- mice exhibited a significantly reduced photoreceptor and a supernormal b..