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It has been estimated that impotence affects
140 million men worldwide. Over half of all men
with impotence are thought to have some medical
cause. The remainder are believed to have
psychogenic causes of impotence. Medical causes
of impotence include diabetes and circulatory,
neurological or urological conditions.
Penile erection is caused by the engorgement of
the penis with blood. This engorgement occurs
when the blood vessels delivering blood to the
penis increase the delivery of blood and the
blood vessels carrying blood away from the penis
decrease the removal of blood. Under normal
conditions, sexual stimulation leads to the
production and release of nitric oxide in the
penis. Nitric oxide then activates the enzyme,
guanylate cyclase, which causes the production
of cyclic guanosine monophosphate (cGMP). It is
the cGMP that is primarily responsible for the
erection by affecting the amount of blood that
the blood vessels deliver and remove from the
penis.
Viagra also reduces the pressure in the
pulmonary artery in a serious condition called
pulmonary arterial hypertension.
Viagra inhibits an enzyme called
phosphodiesterase-5 (PDE5) which destroys the
cGMP. Thus, Viagra prevents the destruction of
cGMP and allows cGMP to accumulate and persist
longer. The longer cGMP persists, the more
prolonged the engorgement of the penis.
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Levitra is the new solution
for Erectile Dysfunction.
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