The cyclic nucleotide second messenger guanosine 3’5’-cyclic monophosphate (cGMP) is an important mediator of signal transduction and hence a wide range of cellular processes. It can be generated by soluble guanylyl cyclase in response to binding of nitric oxide and degraded via members of the phosphodiesterase (PDE) protein family. Zaprinast, the compound from which sildenafil (Viagra™) was developed, is a cGMP-specific phosphodiesterase inhibitor. It moderately inhibits PDE5 and PDE6 with IC50 values of 0.5-0.76 and 0.15 μM, respectively, and weakly inhibits PDE9, PDE10, and PDE11 with IC50 values of 35, 22, and 11-33 μM, respectively. Zaprinast therefore enhances the vasodilatory effects of nitric oxide in a range of vascular tissues by prolonging the cGMP-mediated activation of cGMP-dependent protein kinase. Zaprinast also activates both the rat and human G protein-coupled receptor, GPR35 with EC50 values of 16 nM and 0.84 μM, respectively.
Zaprinast is Yellow-Orange Crystalline Powder
Zaprinast is a selective inhibitor of cyclic-GMP phosphodiesterase (PDE V, calmodulin insensitive). Since cGMP mediates the vasorelaxant action of nitric oxide, as well as the natriuretic and diuretic effect of at rial natriuretic factor (ANF) through the activation of PKG (cGMP dependent protein kinase), such inhibitors may display vasodilating, relaxant, and diuretic effects. These compounds may prove useful in treating hypertension and congestive heart failure.
cGMP phosphodiesterase inhibitor
Zaprinast has been used to determine its inhibitory effect on the meiosis of oocytes by germinal vesicle breakdown (GVBD) assay and to test the inhibitory effect of it on the retinal cells by immunohistochemistry.
ChEBI: 5-(2-propoxyphenyl)-2,3-dihydrotriazolo[4,5-d]pyrimidin-7-one is a member of triazolopyrimidines.
Phosphodiesterase inhibitor, selective for PDE6, 5, 11 and 9 (IC 50 values are 0.15, 0.76, 12.0 and 29.0 μ M respectively).
Zaprinast insubstantially inhibits phosphodiesterase 10 and 11 (PDE10 and PDE11). It also exhibits vasodilating effects.
zaprinast is a pde5 and pde6 inhibitor with inhibiting pde9 at moderately high concentrations (29 mm) [1]. indeed, it showed that inhibition of cgmp hydrolysis by infusion of zaprinast increases the effect of anp on natriuresis with no causing deleterious drops in blood pressure. because it was known that anp receptors is localized within the glomerulus and inner medullary collecting ducts, to determine the cellular localization of pde9 enzyme in kidney will be interesting. [2]. the enzyme displayed a high specificity for cgmp with binding sites for cgmp, and a sensitivity to zaprinast similar to smooth muscle pde5, resulting in both enzymes were named cgmp-pde. however, retinal cgmp-pde was first distinguished as photoreceptor cgmp-pde with being specifically distributed in the retina and having a higher vmax and km values than other cgmp-pdes and being modulated by g protein. [3].
0.15, 0.76, 12.0 and 29.0 μm for pde6, 5, 11 and 9 respectively.
[1] christensen and torphy (1994) isozyme-selective phosphodiesterase inhibitors as antiasthmatic agents. annu.rep.med.chem. 29 185.
[2] soderling sh, bayuga sj, beavo ja. identification and characterization of a novel family of cyclic nucleotide phosphodiesterases. j biol chem. 1998 jun 19; 273(25):15553-8.
[3]. lugnier c. cyclic nucleotide phosphodiesterase (pde) superfamily: a new target for the development of specific therapeutic agents. pharmacol ther. 2006 mar; 109 (3):366-98. epub 2005 aug 15.
