Viagra (sildenafil) works by inhibiting an enzyme called phosphodiesterase-5 (PDE5). This enzyme breaks down cyclic guanosine monophosphate (cGMP), a crucial molecule for achieving and maintaining an erection.
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Increased cGMP Levels
By blocking PDE5, Viagra increases cGMP levels in the smooth muscle cells of the penis. Higher cGMP levels relax these muscles, allowing increased blood flow into the corpora cavernosa – the erectile tissue within the penis.
The Result: Improved Erection
This increased blood flow leads to an erection. The process requires sexual stimulation; Viagra doesn’t cause erections spontaneously.
Specifics of the Process
| 1. Sexual Stimulation | Triggers the release of nitric oxide (NO). |
| 2. Nitric Oxide Action | NO activates an enzyme called guanylate cyclase. |
| 3. cGMP Production | Guanylate cyclase produces cGMP. |
| 4. Muscle Relaxation | Increased cGMP relaxes smooth muscle in the penis. |
| 5. Blood Flow Increase | Relaxed muscles allow increased blood flow into the corpora cavernosa. |
| 6. Erection | Increased blood flow produces an erection. |
Factors Affecting Viagra’s Action
Individual factors, such as age and overall health, can influence how effectively Viagra works. Always consult your doctor before using Viagra or any medication.
