Figure 1. Molecular pathway of erections (black) and location of action of medications for erectile dysfunction (red).
AC, adenylyl cyclase; ATP, adenosine triphosphate; cAMP, cyclic adenosine monophosphate; cGMP, cyclic guanosine monophosphate; GC, guanylate cyclase; GTP, guanosine triphosphate; NE, norepinephrine; NO, nitric oxide; PDE5, phosphodiesterase type 5; PDE5i, phosphodiesterase type 5 inhibitor; PDE, phosphodiesterase; PDEi, phosphodiesterase inhibitor; PGE1, prostaglandin E1.