Sildenafil,N-desmethyl-sildenafil and Zaprinast enhance photoreceptor response in the isolated rat retina

    loading  Checking for direct PDF access through Ovid


Here we report that the active component of Viagra, Sildenafil and the first metabolite, N-desmethyl-sildenafil (UK-103, 320) increased the amplitude of flash-evoked electroretinogram (ERG) of dark-adapted albino rat retina. Effects of Sildenafil and N-desmethyl-sildenafil were comparable to those of the known phosphodiesterase inhibitor, Zaprinast. The photoreceptor cell response was isolated by blocking the glial K+ ion-buffering and the on-bipolar components of the ERG with the use of BaCl2 (500 μM) and the specific type VI metabotropic glutamate receptor agonist, dl-2-amino-4-phosphonobutyric acid (25 μM), respectively. Zaprinast, Sildenafil and N-desmethyl-sildenafil (1 μM each) increased the amplitude of photoreceptor cell response either. Besides, Sildenafil was significantly more effective than N-desmethyl-sildenafil. These findings suggest an increased sensitivity of photoreceptor cells in the presence of Sildenafil and it is metabolite.

    loading  Loading Related Articles