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 (500μM) and the specific type VI metabotropic glutamate receptor agonist, DL-2-amino-4-phosphonobutyric acid (25μM), respectively. Zaprinast, Sildenafil and N-desmethyl-sildenafil (1μM 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.
- DL-2-amino-4-phosphonobutyric acid
- Phosphodiesterase inhibitors
- Rat retina
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience
- Cell Biology