Viagra, or sildenafil, primarily targets a specific enzyme called phosphodiesterase-5 (PDE5). This enzyme normally breaks down a molecule called cyclic guanosine monophosphate (cGMP). cGMP plays a crucial role in blood vessel relaxation.
Impact on Blood Flow
By inhibiting PDE5, Viagra increases cGMP levels. Higher cGMP levels cause the smooth muscles in the blood vessels of the penis to relax, allowing for increased blood flow. This increased blood flow is what facilitates an erection.
Specifics of the Process
The process begins with sexual stimulation, triggering the release of nitric oxide (NO). NO then activates an enzyme called guanylate cyclase, leading to increased cGMP production. Viagra’s action enhances and prolongs this effect, ensuring sufficient blood flow for erection maintenance.
Important Note on Timing
It’s important to understand Viagra doesn’t directly cause erections; sexual stimulation is still necessary. Viagra simply helps the body respond more effectively to that stimulation by improving blood flow to the penis. The drug’s effects typically last for several hours.
