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)

Nitroprusside (NP) and nitroglycerin (NG) are potent vasodilators that are used clinically on the basis of their abilities to cause relaxation of smooth muscle. In vitro, both agents cause activation of guanylate cyclase, resulting in increased intracellular cGMP. They also have effects on arachidonate metabolism. Despite apparent similarities in their mechanisms of action, the two drugs have different therapeutic applications based in part on differences in their effectiveness on the arterial and venous systems in vivo. To understand better their target tissue preference, slices of aorta and vena cava were incubated with the agents; cGMP and the vasodilatory prostanoid, prostacyclin, were quantified. NP was more effective in increasing the cGMP content of aorta than of vena cava; it was more active than NG in both tissues. Prostaglandin formation by vascular tissue was influenced by the preliminary equilibration period. Under optimal conditions, it appeared that NG enhanced prostacyclin formation in aorta more than did NP. This in vitro model for NP and NG action may be useful in studying the mechanisms of action of these and other vasoactive agents.
 ...
PMID:Effects of nitroprusside and nitroglycerin on cGMP content and PGI2 formation in aorta and vena cava. 253 35

The objective of this study was to examine the relationship between responses of bovine intrapulmonary artery and vein to arachidonic acid and cyclic nucleotide levels in order to better understand the mechanism of relaxation elicited by arachidonic acid and acetylcholine. Arachidonic acid relaxed phenylephrine-precontracted arterial rings and elevated both cyclic GMP and cyclic AMP levels in arteries with intact endothelium. In contrast, endothelium-damaged arterial rings contracted to arachidonic acid without demonstrating significant changes in cyclic nucleotide levels. Indomethacin partially inhibited endothelium-dependent relaxation and abolished cyclic AMP accumulation whereas methylene blue, a guanylate cyclase inhibitor, partially inhibited relaxation and abolished cyclic GMP accumulation in response to arachidonic acid. All vessel responses were blocked by a combination of the two inhibitors. Prostaglandin (PG) I2 relaxed arterial rings and elevated cyclic AMP levels whereas PGE2 and PGF2 alpha caused contraction, suggesting that the indomethacin-sensitive component of arachidonic acid-elicited relaxation is due to PGI2 formation and cyclic AMP accumulation. The methylene blue-sensitive component is attributed to an endothelium-dependent but cyclooxygenase-independent generation of a substance causing cyclic GMP accumulation. Intrapulmonary veins contracted to arachidonic acid with no changes in cyclic nucleotide levels and PGI2 was without effect. Homogenates of intrapulmonary artery and vein formed 6-keto-PGF1 alpha, PGF2 alpha and PGE2 from [14C]arachidonic acid, which was inhibited by indomethacin. Thus, bovine intrapulmonary vein may not possess receptors for PGI2. The failure of endothelium-intact vein to relax to acetylcholine may be related to the lack of a relaxant effect by arachidonic acid, perhaps attributed to the absence of generation of an endothelium-derived relaxing factor.
 ...
PMID:Differences in responsiveness of intrapulmonary artery and vein to arachidonic acid: mechanism of arterial relaxation involves cyclic guanosine 3':5'-monophosphate and cyclic adenosine 3':5'-monophosphate. 298 87

Lysimachia clethroides is widely used in traditional herbal medicine for many purposes, especially for blood vessel-related diseases in Korea and East Asia. Experiments were undertaken to determine whether hydro-alcoholic extract obtained from L. clethroides (LCE) has vasorelaxant activity in the rat aorta rings and, if so, to elucidate the underlying mechanism. Rat aorta rings were suspended in organ chambers for the measurement of changes in isometric tension in the presence or absence of several inhibitors. LCE induced endothelium-dependent vasodilation (ED50 = 6.1 mug/mL) and that was abolished by nitric oxide synthase inhibitor, N-nitro-L-arginine, and guanylyl cyclase inhibitor, 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one, PI3-kinase inhibitor, wortmannin, and cell permeable superoxide dismutase. In addition, LCE decreased vessels contraction by phenylephrine. Prostaglandin synthesis inhibitor, indometacin, and inhibitors of endothelium-derived hyperpolarizing factor, charybdotoxin plus apamin, did not affect vasodilatory effect of LCE. In cultured endothelial cells, LCE-induced phosphorylation of serine 1177-endothelial nitric oxide synthase and serine 473-Akt. LCE inhibited strongly nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in smooth muscle cells and angiotensin II-induced contraction of rat aorta. Finally, increased oxidative stress in rat aorta-induced by angiotensin II is ameliorated by LCE. Taken together, LCE induces an endothelium-dependent vasodilation and might be involved, at least in part, the activation of the nitric oxide-cyclic guanosine monophosphate pathway. In addition, LCE decreases oxidative stress in aorta by inhibition of NADPH oxidase activity. The present findings indicate that LCE could be a candidate of herbal medicine for cardiovascular diseases associated with disturbed NO production and endothelial dysfunction.
 ...
PMID:Lysimachia clethroides extract promote vascular relaxation via endothelium-dependent mechanism. 2016 88