Review article

Phosphodiesterase Type 5 and Sildenafil

Branimir Šincek

Abstract

Numerous physiological cellular processes
are regulated by intracellular signal pathways. Cyclic
nucleotide monophosphates, whose levels determine
intracellular processes, are incorporated into a high number
of signal cascades. Phosphodiesterases are the enzymes of
unique structure whose role is to maintain the physiological
cellular levels of cyclic nucleotides. Cyclic guanosine
monophosphate (cGMP) plays an important role in the
regulation of vascular smooth muscle tone. Sildenafi l is
the fi rst oral selective inhibitor of phosphodiesterase type
5 (PDE5). It increases the cGMP levels and thus indirectly
reduces the quantity of calcium ions in smooth muscle
cells, which results in muscle relaxation. This property
of sildenafi l is employed in the treatment of pathological
conditions or diseases such as erectile dysfunction and
hypoxia-induced pulmonary hypertension, which result from
reduced cellular cGMP levels due to the increased PDE5
activity.

Keywords

cyclic guanosine monophosphate; phosphodiesterase type 5; sildenafi l; erectile dysfunction; hypoxiainduced pulmonary hypertension

Hrčak ID:

19005

URI

https://hrcak.srce.hr/19005

Publication date:

15.11.2004.

Article data in other languages: croatian

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