A 55 year old man comes to his primary care clinician of erectile dysfunction. He is given a prescription for sildenafil, and on follow-up, repos that his ability to sustainn an erection has been improved markedly by this treatment. The action of which of the following vasoactive mediators would primarily be prolonged in this patient
High-Yield Explanation
The action of Nitric Oxide would primarily be prolonged in this patient. Sildenafil: It is used for the treatment of erectile dysfunction, which inhibits cGMP-specific phosphodiesterase-5 (PDE-5), an enzyme that degrades cGMP , thereby effectively prolonging the action of NO. Penile erection is produced by release of Nitric Oxide (NO), with consequent vasodilation and engorgement of the corpora cavernosa. Ref: Ganong&;s Review of medical physiology 26th edition PGno: 415