BAY 41-2272 [5-Cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4-ylamine]-Induced Dilation in Ovine Pulmonary Artery: Role of Sodium Pump

Abstract

The mechanisms of relaxation to nitric oxide (NO)-independent soluble guanylyl cyclase (sGC) activator BAY 41-2272 [5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo [3,4-b]pyridine-3-yl]pyrimidin-4-ylamine] were investigated in isolated ovine pulmonary artery. BAY 41-2272 (1 nM-10 M) produced concentration-dependent relaxation of endothelium-denuded pulmonary artery rings (pD 2 ϭ 6.82 Ϯ 0.16; E max ϭ 92.30 Ϯ 2.31%; n ϭ 8), precontracted with 1 M 5-hydroxytryptamine (serotonin). 1-H-[1,2,4]Oxadiazole[4,3-a]quinoxalin-1-one (ODQ; 10 M), an inhibitor of sGC, partially inhibited (E max ϭ 57.10 Ϯ 3.10%; n ϭ 6) the relaxation response of BAY 41-2272. In comparison with ODQ, sodium pump inhibitor ouabain (1 M) produced a greater decrease in the vasodilator response of BAY 41-2272 (E max ϭ 20.17 Ϯ 4.55%; n ϭ 6). K ϩ -free solution also attenuated (E max ϭ 39.97 Ϯ 3.52%; n ϭ 6) BAY 41-2272-induced relaxation. ODQ (10 M) plus 1 M ouabain abolished the relaxant response of BAY 41-2272 (E max ϭ 12.09 Ϯ 3.76%, n ϭ 6 versus vehicle control dimethyl sulfoxide; E max ϭ 15.83 Ϯ 1.72%, n ϭ 6). 2,2Ј,pyrrolo [3,4-I] [1,6]benzodiazocine-10-carboxylic acid methyl ester (2 M), a specific inhibitor of protein kinase G had no effect on 10 M ODQ-insensitive relaxation evoked by BAY 41-2272. BAY 41-2272 (10 M) inhibited Ca 2ϩ -induced contractions in K ϩ -depolarized preparations. BAY 41-2272 (10 M) caused about a 14-fold increase in the intracellular cGMP over the basal level, which was completely inhibited by 10 M ODQ. BAY 41-2272 (0.1, 1.0, and 10 M) significantly (P Ͻ 0.05) increased ouabain-sensitive 86 Rb uptake in a concentration-dependent manner. BAY 41-2272 (10 M) also stimulated sarcolemmal Na ϩ -K ϩ -ATPase activity. However, 10 M ODQ had no significant effect on either basal or BAY 41-2272-stimulated 86 Rb uptake/Na ϩ -K ϩ -ATPase activities. In conclusion, this study provides the first evidence of sodium pump stimulation by BAY 41-2272 independent of cGMP as an additional mechanism to sGC activation in relaxation of ovine pulmonary artery.Endogenous nitric oxide (NO), derived from vascular endothelium is an important regulator of vascular functions. Thus, endothelial dysfunction is associated with several vascular disorders, such as atherosclerosis, systemic and pulmonary hypertension, and angina pectoris (Ignarro et al., 1999). Nitrovasodilators have been clinically used for the therapeutic management of NO deficiency-related conditions, such as angina pectoris and pulmonary hypertension (Sperling and Creager, 1999). However, there are certain disadvantages with NO donor-based therapy, which include development of tolerance after prolonged use (Parker, 1989), peroxinitrite formation that may lead to protein S-nitrosylation (Stamler, 1994), tyrosine nitration (Beckman et al., 1994), and the absence of clinically significant antiplatelet activity as with organic nitrates (Parker, 1989). Therefore, there has been search in the recent past for NO-independent sGC activators that could be used clinically for the treatment ...

Phosphodiesterases Regulate BAY 41-2272-Induced VASP Phosphorylation in Vascular Smooth Muscle Cells

“…Based on the recent findings for BAY in terms of its mechanism of action and dependence on sGC and cGMP (Stasch et al, 2001; Bawankule et al, 2005; Teixeira et al, 2006), we sought to determine if BAY-induced increases in cGMP are via direct stimulation of sGC. Primary VSMCs were incubated with two chemically dissimilar inhibitors of sGC: NS 2028 (NS, 1 μM) or ODQ (10 μM), prior to stimulation with BAY (10 μM; Garthwaite et al, 1995; Morbidelli et al, 2010).…”

“…One other possible explanation is that BAY activates some other unidentified kinase in this cell that can phosphorylate VASP. BAY has also been shown to have effects apart from NO such as inhibition of Ca 2+ influx, stimulation of the sodium pump, or inhibition of PDE5 (Mullershausen et al, 2004; Bawankule et al, 2005; Teixeira et al, 2006). The latter is one possible explanation for this finding because an inhibition of PDE5 would increase cGMP and thus lead to phosphorylation of VASP.…”

Light-induced vs. bradykinin-induced relaxation of coronary arteries: do S-nitrosothiols act as endothelium-derived hyperpolarizing factors?

“…Combined with the lack of S-nitrosothiol-induced cGMP generation, these data indicate that S-nitrosothiols either activate Na þ /K þ -ATPase directly or via guanylyl cyclase without cGMP acting as intermediate. Evidence favoring the latter concept comes from studies with the guanylyl cyclase activator BAY 41-2272 in ovine pulmonary arteries [37]. In these vessels, BAY 41-2272 activated Na þ /K þ -ATPase in a cGMP-independent manner.…”

Docking Studies, Synthesis, and Evaluation of Antioxidant Activities of N-Alkylated, 1,2,4-Triazole, 1,3,4-Oxa-, and Thiadiazole Containing the Aminopyrazolopyridine Derivatives

“…1H-Pyrazolo [3,4-b]pyridines comprise a very interesting class of compounds because of their significant and versatile biological and pharmacological activities, such as antimalarial [1] antiproliferative [2] antimicrobial [3][4][5] inhibition of cyclin-dependent kinases [6] and cardiovascular [7][8][9] antiviral [10][11][12] and antileishmanial [13] activities. Pyrazole fused pyridines and pyrimidines are known to possess a wide range of biological activity.…”