Effects of 5-Cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4-ylamine (BAY 41-2272) on Smooth Muscle Tone, Soluble Guanylyl Cyclase Activity, and NADPH Oxidase Activity/Expression in Corpus Cavernosum from Wild-Type, Neuronal, and Endothelial Nitric-Oxide Synthase Null Mice

Abstract

We aimed to characterize the relaxation induced by the soluble guanylyl cyclase (sGC) stimulator 5-cyclopropyl-2-[1-(2-fluorobenzyl)-1H-pyrazolo [3,4-b]pyridine-3-yl]pyrimidin-4-ylamine (BAY 41-2272) and its pharmacological interactions with nitric oxide (NO) in the corpus cavernosum (CC) from wild-type (WT), endothelial nitric-oxide synthase (eNOS), and neuronal (n)NOS Ϫ/Ϫ mice. The effect of BAY 41-2272 on superoxide formation and NADPH oxidase expression was also investigated. Tissues were mounted in myographs for isometric force recording. Enzyme immunoassay kits were used for cGMP determination. sGC activity was determined in the supernatant fractions of the cavernosal samples by the conversion of GTP to cGMP. Superoxide formation and expression of NADPH oxidase subunits were studied using the reduction of ferricytochrome c and Western blot analysis, respectively. Penile erection is the end result of corpus cavernosum (CC) smooth muscle relaxation initiated by nitric oxide (NO). This process is mediated in part by nitrergic nerves expressing neuronal NO synthase (nNOS), because sexual stimulation results in the peripheral release of NO. The neurally derived NO induces the initial dilation of the helicine resistance arterioles as well as the trabecular smooth muscle, resulting in an increased arterial blood inflow that further activates the endothelial NOS (eNOS), releasing an additional amount of NO down into the smooth muscle layers. Through the activation of soluble guanylyl cyclase (sGC), NO induces the enzymatic conversion of GTP to cGMP. In turn, cGMP acts as This study was supported by National Institutes of Health Grants HL-71138 and HL-74167.1 Deceased July 1, 2007. Article, publication date, and citation information can be found at

Beneficial Effect of the Nitric Oxide Donor Compound 3-(1,3-Dioxoisoindolin-2-yl)Benzyl Nitrate on Dysregulated Phosphodiesterase 5, NADPH Oxidase, and Nitrosative Stress in the Sickle Cell Mouse Penis: Implication for Priapism Treatment

“…In our study, elevated gp91 phox and 3-nitrotyrosine protein expressions in penile tissues from SCD and dNOS 2/2 were detected, which is consistent with previous studies Bivalacqua et al, 2013). In mouse erectile tissue, the soluble guanylyl cyclase stimulator BAY 41-2272 reduces superoxide anion formation through inhibition of NADPH oxidase activity and reduction of NADPH oxidase subunit gp91 phox expression, an effect mediated by a cGMP-dependent mechanism (Teixeira et al, 2007;Nunes et al, 2015). Likewise, the PDE5 inhibitor sildenafil inhibits p47 phox NADPH oxidase subunit expression and superoxide anion formation in cavernosal smooth muscle cells (Koupparis et al, 2005).…”

Beneficial Effect of the Soluble Guanylyl Cyclase Stimulator BAY 41-2272 on Impaired Penile Erection in db/db−/− Type II Diabetic and Obese Mice

“…Considering that decreased NO availability is a common factor in diabetes-related ED, prolonged cavernosal relaxation in an in vivo situation would be extremely beneficial, leading to or improving the quality of an erection. In addition, this result supports the concept that BAY 41-2272 interacts with endogenous NO (Teixeira et al, 2006c(Teixeira et al, , 2007.…”

“…Figure 2B shows that BAY 41-2272 potentiates SNPinduced relaxation in diabetic db/db 2/2 mice. Corroborating this result, in wild-type mice the endothelium-independent relaxation response curves of CC induced by SNP were shifted to the left as a function of increasing concentrations of BAY 41-2272 (Teixeira et al, 2007).…”

“…These findings are consistent with a previous report that NADPH oxidase-dependent superoxide generation is significantly increased after incubating mouse CC with U46619, a stimulator of superoxide formation. This increase in superoxide production was reversed by BAY 41-2272 via decreased protein expression of NADPH oxidase subunits (Teixeira et al, 2007).…”

“…In a NO-deficient rat model, longterm oral treatment with BAY 41-2272 improved the impaired cavernosal relaxation (Claudino et al, 2011). In a previous investigation of the effects of BAY 41-2272 in mice CC, our group showed that this compound reverses the increased NADPH oxidase-dependent superoxide generation by decreasing protein expression of its subunits gp91 phox and p22 phox (Teixeira et al, 2007). The NADPH oxidase enzyme complex is composed of a membrane-bound cytochrome, which includes subunits gp91 phox and p22 phox , and a cytosolic component composed of five subunits, including p47…”