Final Jeopardy
0
Viagra (sildenafil) can cause blue-tinted vision as a transient side effect, called cyanopsia, due to a disproportionate effect on short-wavelength cones. In smooth muscle, Viagra causes relaxation and vasodilation by increasing cGMP levels. In photoreceptors, Viagra would be expected to inhibit the activity of which enzyme in the phototransduction cascade?
Answer: cGMP phosphodiesterase
