Consider the phototransduction cascade. Viagra (sildenafil) is a drug that inhibits phosphodiesterases. What might you expect would be a side effect of Viagra related to visual function?

Question

Quizplus · Accepted Answer

Viagra inhibits phosphodiesterases, which are responsible for breaking down cGMP. In the phototransduction cascade, high levels of cGMP keep ion channels open, allowing for the influx of positive ions and depolarization of the photoreceptor cells. By inhibiting phosphodiesterases, Viagra would impair the ability to degrade cGMP, thus potentially affecting the cell's ability to hyperpolarize in response to light, leading to prolonged depolarization and affecting visual function.

Consider the Phototransduction Cascade