Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of the present study was: 1) to determine the effects of the novel selective inhibitor of guanylyl cyclase, ODQ (1H-[1,2,4]oxadiazolo[4,3,-a]quinoxaline-1-one) on basal and agonist-stimulated cyclic GMP levels in cultured porcine aortic endothelial cells and bovine pulmonary artery strips; 2) to determine its effects on agonist-induced relaxations of bovine pulmonary artery strips; and 3) to compare pulmonary artery cyclic GMP levels with vessel relaxation. ODQ (1 nM-30 microM) inhibited cyclic GMP accumulation in endothelial cells stimulated with S-nitrosoglutathione, nitroprusside and 3-morpholine-sydnonimine at IC50 values of 40 to 100 nM. Complete suppression of cyclic GMP generation was observed at approximately 10 microM. Relaxation of pulmonary artery strips induced by S-nitrosoglutathione, nitroprusside, glycerol trinitrate, nitrite (all endothelium-independent), bradykinin and the Ca++ ionophore A23187 (endothelium-dependent) were antagonized by ODQ (1-10 microM) in a concentration-dependent way. A consistent feature of the inhibitor was that maximal relaxant effects also were reduced. Basal levels and agonist-induced increases in arterial tissue cyclic GMP were inhibited in the same concentration range. However, tissue cyclic GMP production correlated poorly with pulmonary artery relaxation in that relaxations induced by S-nitrosoglutathione were only inhibited in part (50%), whereas rises in cyclic GMP were abolished completely by ODQ (10 microM). Furthermore, at 1 microM, ODQ had no effect on relaxation induced by endothelium-dependent agonists, but prevented entirely stimulation of cyclic GMP accumulation in arterial tissue. These results suggest that ODQ inhibits nitrovasodilator-induced and endothelium-dependent relaxation through inhibition of guanylyl cyclase activation, but also point to the presence of a cyclic GMP-independent component of relaxation in bovine pulmonary artery.
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PMID:Novel guanylyl cyclase inhibitor potently inhibits cyclic GMP accumulation in endothelial cells and relaxation of bovine pulmonary artery. 861 57

Soluble guanylyl cyclase (sGC), a ubiquitously expressed heme-containing receptor for nitric oxide (NO), is a key mediator of NO-dependent processes. In addition to NO, a number of synthetic compounds that target the heme-binding region of sGC and activate it in a NO-independent fashion have been described. We report here that dicyanocobinamide (CN2-Cbi), a naturally occurring intermediate of vitamin B(12) synthesis, acts as a sGC coactivator both in vitro and in intact cells. Heme depletion or heme oxidation does not affect CN2-Cbi-dependent activation. Deletion mutagenesis demonstrates that CN2-Cbi targets a new regulatory site and functions though a novel mechanism of sGC activation. Unlike all known sGC regulators that target the N-terminal regulatory regions, CN2-Cbi directly targets the catalytic domain of sGC, resembling the effect of forskolin on adenylyl cyclases. CN2-Cbi synergistically enhances sGC activation by NO-independent regulators 3-(4-amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine (BAY41-2272), 4-[((4-carboxybutyl){2-[(4-phenethylbenzyl)oxy]phenethyl}amino) methyl [benzoic]-acid (cinaciguat or BAY58-2667), and 5-chloro-2-(5-chloro-thiophene-2-sulfonylamino-N-(4-(morpholine-4-sulfonyl)-phenyl)-benzamide sodium salt (ataciguat or HMR-1766). BAY41-2272 and CN2-Cbi act reciprocally by decreasing the EC(50) values. CN2-Cbi increases intracellular cGMP levels and displays vasorelaxing activity in phenylephrine-constricted rat aortic rings in an endothelium-independent manner. Both effects are synergistically potentiated by BAY41-2272. These studies uncover a new mode of sGC regulation and provide a new tool for understanding the mechanism of sGC activation and function. CN2-Cbi also offers new possibilities for its therapeutic applications in augmenting the effect of other sGC-targeting drugs.
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PMID:Cobinamides are novel coactivators of nitric oxide receptor that target soluble guanylyl cyclase catalytic domain. 2217 Oct 90