Description_x000D_ Application_x000D_ Sildenafil citrate salt has been used:_x000D_ • as an inhibitor of cGMP phosphodiesterase 5 (PDE5) in mice and drosophila_x000D_ • as a reference standard in evaluating the aphrodisiac activity of Cydonia oblonga extracts_x000D_ • as a reference standard in phosphodiesterase 5 (PDE 5) inhibition assay_x000D_ Packaging_x000D_ 5, 25 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ Sildenafil is a potent, selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5). Sildenafil is used to treat erectile dysfunction and pulmonary arterial hypertension. NO activates guanylate cyclase, which results in increased levels of cGMP, producing smooth muscle relaxation. Sildenafil enhances the effect of NO by inhibiting PDE5, which is responsible for degradation of cGMP._x000D_ Features and Benefits_x000D_ This compound is a featured product for Cyclic Nucleotide research. Click here to discover more featured Cyclic Nucleotide products. Learn more about bioactive small molecules for other areas of research at sigma.com/discover-bsm._x000D_ This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more._x000D_ This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®Pfizer), a collection of 90 Pfizer-developed drugs and research tools. Click here to learn more._x000D_ This compound is featured on the Phosphodiesterases page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here._x000D_ Other Notes_x000D_ This compound was developed by Pfizer for Cyclic Nucleotides research. To learn more about Sigma′s partnership with Pfizer and view other authentic, high-quality Pfizer compounds, visit sigma.com/bsm-pfizer._x000D_ To browse the list of other pharma-developed compounds and Approved Drugs/Drug Candidates, click here._x000D_ Legal Information_x000D_ Sold for research purposes under agreement from Pfizer Inc._x000D_ LOPAC is a registered trademark of Sigma-Aldrich Co. LLC_x000D_ Pfizer is a registered trademark of Pfizer, Inc.