Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:4.6.1.2 (guanylate cyclase)
8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, and 3-chloroperoxybenzoic acid (CPB) and 15-HPETE relaxed, in a concentration dependent manner rat aortic rings contracted with PGF2 alpha (1 X 10(-5)). Relaxation is not inhibited by either indomethacin (2 X 10(-5) M), a cyclo-oxygenase inhibitor or eicosatetraynoic acid (1 X 10(-5) M), a dual cyclo-oxygenase and lipoxygenase inhibitor. Rings with intact endothelium relaxed to a greater degree on exposure to CPB and 15-HPETE. Methylene blue, a soluble guanylate cyclase inhibitor (1 X 10(-5) M) blocked the relaxation elicited by the five peroxides, whereas both superoxide dismutase (scavenger of superoxide anion) and mannitol (scavenger of hydroxyl radical) have no effect. We conclude that relaxation of vascular smooth muscle is a general property of peroxides and that the endothelium may in some instances facilitate this effect.
...
PMID:Induction of vascular relaxation by hydroperoxides. 302 Nov 20

The effects of organic nitrates on tone and tissue cyclic nucleotide levels were studied, using canine coronary, mesenteric and renal arteries, and femoral veins. Glyceryl trinitrate (GTN) relaxed all vascular tissues examined and increased tissue cyclic GMP (cGMP) levels in a concentration-dependent manner, but GTN induced no significant changes in cyclic AMP (cAMP) levels. An increase in cGMP levels induced by 10 microM of GTN in coronary arteries was observed before the onset of relaxation. Methylene blue, an inhibitor of guanylate cyclase, inhibited the relaxant effect of GTN and decreased cGMP levels. In contrast, M & B 22,948, an inhibitor of cGMP phosphodiesterase, not only enhanced relaxation by GTN, but also increased cGMP levels. Other organic nitrates, pentaerythritol tetranitrate (PETN), nicorandil (NIC), and isosorbide dinitrate (ISDN), also relaxed coronary arteries and increased cGMP levels in a concentration-dependent manner. A significant correlation was observed between percentage increases in cGMP levels and percentage relaxation by 10 microM of GTN, PETN, NIC, and ISDN (r = 0.952, p less than 0.001). Plasma concentrations of 4 organic nitrates inversely correlated with percentage increases in cGMP levels by 10 microM of these agents in coronary arteries (r = -0.845, p less than 0.001). These results suggest that an increase in cGMP is responsible for relaxation in vascular smooth muscles by organic nitrates, and that therapeutic plasma concentrations may be estimated by the degree of increase in cGMP levels induced by their administration.
...
PMID:Role of cyclic GMP of canine vascular smooth muscle in relaxation by organic nitrates. 302 46

The role of the endothelium in modulating cyclic nucleotide levels and intrinsic smooth muscle tone was studied in isolated rings of bovine intrapulmonary artery and vein. Cyclic 3',5'-guanosine monophosphate (cGMP) levels were threefold to fourfold higher in unrubbed artery and vein than in vessels that had been denuded of endothelium. Cyclic 3',5'-adenosine monophosphate (cAMP) levels were twofold higher in unrubbed than in endothelium-denuded artery, but no differences were observed in veins. Methylene blue, an inhibitor of guanylate cyclase, decreased cGMP but not cAMP levels, and this was accompanied by increases in smooth muscle tone. M&B 22,948, an inhibitor of cGMP-phosphodiesterase, increased cGMP but not cAMP levels, and this was accompanied by decreases in smooth muscle tone. Unrubbed vessels were more sensitive than endothelium-denuded vessels to the actions of both methylene blue and M&B 22,948, and this may be attributed to endothelium-dependent increases in cGMP turnover. Moreover, unrubbed vessels were more sensitive than endothelium-denuded vessels to contractile responses to phenylephrine and potassium, and these responses were potentiated by methylene blue and attenuated by M&B 22,948. Although indomethacin lowered cAMP levels in unrubbed artery, no changes in tone or contractile responsiveness were observed. A consistent observation was that the smaller branches of unrubbed but not endothelium-denuded intrapulmonary artery and vein had higher levels of cGMP but not cAMP, were sensitive to endothelium-dependent vasodilators, were more sensitive to methylene blue, and would not maintain a steady level of submaximal tone to phenylephrine when compared with larger branches from a common vascular bed.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Endothelium-dependent modulation of cGMP levels and intrinsic smooth muscle tone in isolated bovine intrapulmonary artery and vein. 303 74

The effects of nitrates on Ca2+ increase and cyclic nucleotide content in human platelets were studied. Nitroglycerin, isosorbide dinitrate and sodium nitroprusside were found to inhibit the intracellular Ca2+ increase induced by the platelet activating factor, ADP and a stable thromboxane A2 analog--U46619. The inhibiting effect of sodium nitroprusside manifested itself at lower concentrations than those of nitroglycerin and isosorbide dinitrate. Nitroglycerin suppressed the Mn2+ entry into the cells and caused a 2-fold increase of the cGMP content which correlates with the calcium blocking activity. Methylene blue, a guanylate cyclase and glutathione reductase inhibitor, decreased the calcium blocking effect of nitroglycerin and its influence on the cyclic nucleotide content but failed to suppress the inhibitory effect of sodium nitroprusside. The data obtained suggest that the effects of nitrates on platelets are mediated by their influence on guanylate cyclase which leads to a cyclic nucleotide content increase and to a calcium blocking effect.
...
PMID:[Calcium-blocking effect of nitro compounds in human platelets: correlation with changes in the cyclic guanosine monophosphate level]. 303 39

Helical strips of human coronary arteries contracted in response to histamine concentration dependently, they relaxed with low concentrations and contracted with high concentrations. Treatment with cimetidine potentiated contraction in the strips with intact and damaged endothelium to a similar extent and attenuated relaxation. Removal of endothelium abolished relaxation and potentiated contraction in the cimetidine-treated strips. Methylene blue increased the contractile response to histamine in the strips with endothelium but did not alter the response in the damaged-endothelium strips. Histamine-induced relaxations in the intact strips were suppressed or abolished by treatment with ETYA, AA861, a lipoxygenase inhibitor, and by chlorpheniramine but were unaffected by indomethacin. Chlorpheniramine also abolished amine-induced contraction. It may be concluded that histamine-induced contraction in human coronary arteries is mediated by H1 receptors in smooth muscle, and relaxation is mediated by H2 receptors in smooth muscle and H1 receptors in endothelium. Also, stimulation of the endothelial H1 receptor liberates vasodilator substance and possibly activates smooth muscle guanylate cyclase to accumulate cellular cyclic guanosine monophosphate.
...
PMID:Mechanism of histamine actions in human coronary arteries. 311 61

1. Injection of acetylcholine (ACh, 0.0005-2 micrograms/kg) or glyceryl trinitrate (GTN, 0.01-20 micrograms/kg) into the femoral artery increased femoral artery diameter, femoral blood flow and heart rate, and reduced femoral vascular resistance and systemic arterial blood pressure in anaesthetized dogs. The intravenous (i.v.) injection of ACh (2 micrograms/kg) produced a small decrease in systemic arterial pressure and an increase in heart rate, but did not dilate the hindlimb vessels. 2. Methylene blue, a guanylate cyclase inhibitor, continuously infused into the femoral artery (10 mg/min), attenuated the increase in femoral artery diameter and femoral blood flow, and the decrease in femoral vascular resistance produced by intra-arterial injections of both ACh and GTN. 3. In addition, methylene blue potentiated the decrease in systemic arterial pressure produced by ACh (injected directly into the femoral artery or i.v.), but did not affect the depressor response to GTN. This selective potentiation of ACh-induced hypotension was not affected by autonomic ganglion blockade with hexamethonium (25 mg/kg, i.v.). 4. These results suggest that both ACh- and GTN-induced vasodilatation in vivo occurs through a mechanism involving guanylate cyclase activation in large arteries and resistance vessels in the dog hindlimb. Methylene blue inhibited the local vasodilator actions of ACh in the femoral vasculature despite potentiating the systemic depressor response to that agent.
...
PMID:Inhibition of vasodilatation by methylene blue in large and small arteries of the dog hindlimb in vivo. 315 61

Transmural electrical stimulation of isolated ring segments of the rabbit carotid artery caused frequency-dependent contractions; these were blocked by tetrodotoxin or prazosin. Mechanical or chemical removal of the endothelium markedly augmented responses to electrical stimulation. Inhibition of norepinephrine uptake and metabolism with cocaine, hydrocortisone, and pargyline increased contractions in rings with endothelium more than those without endothelium, but responses remained greater in rings denuded of endothelium. Methylene blue, an inhibitor of guanylate cyclase, enhanced responses to electrical stimulation of rings with intact endothelium only. Combined inhibition of guanylate cyclase and norepinephrine disposition increased the contractions and abolished the difference between the responses of rings with and without endothelium. In a perfusion-cascade system, the perfusate of donor segments with endothelium relaxed a bioassay ring without endothelium. Electrical stimulation of the segment caused no further relaxation of the bioassay ring. However, contractions caused by electrically stimulating the bioassay ring were depressed during superfusion with the perfusate of segments with, but not without, endothelium, indicating that vasodilators spontaneously released from the endothelium inhibit responses to nerve stimulation. These observations suggest that inhibition by the endothelium of the response to adrenergic nerve stimulation results from 1) spontaneous release of endothelium-derived vasodilators and 2) disposition of norepinephrine by the endothelial cells.
...
PMID:Endothelium inhibits responses of rabbit carotid artery to adrenergic nerve stimulation. 349 86

The vascular endothelium appears obligatory for the expression of the vasodilating property of most polypeptides. A number of polypeptides were studied on the rat aortic ring preparation which was pre-contracted with phenylephrine and only basic polypeptides containing one or more arginine residues elicited relaxation which was endothelium dependent. These peptides included melittin and poly-L-Arg. The basic polypeptide poly-L-Lys also elicited endothelium dependent relaxation, but to a lesser extent than arginine containing polypeptides. Two basic polypeptides, apamin and mastoparan do not promote endothelium dependent relaxation. The former contains arginine between disulfide bonds and in the latter arginine is absent. Basic amino acids and dipeptides which contain arginine, and also polyamines did not elicit relaxation even at high concentrations (10(-3) M). The relaxation elicited by melittin, poly-L-Arg and poly-L-Lys was inhibited by ETYA, NDGA, p-bromophenacyl bromide and not by indomethacin. Methylene blue, an inhibitor of soluble guanylate cyclase, also abolished the relaxation. We suggest that arginine containing peptides may relax vascular smooth muscle by acting directly on the vascular smooth muscle (eg: atriopeptins) and/or or by eliciting release of a relaxing factor(s) from the endothelium.
...
PMID:Endothelium dependent vascular relaxation by arginine containing polypeptides. 380 Oct 12

Relaxation by nitroglycerin, sodium nitrite, and amyl nitrite of bovine coronary arterial smooth muscle was inhibited by the oxidant methylene blue. Methylene blue also inhibited activation of bovine coronary arterial soluble guanylate cyclase by nitroglycerin, which required addition of cysteine. At concentrations less than 10 mM, sodium nitrite required the addition of one of several thiols or ascorbate to activate guanylate cyclase from bovine coronary artery. Guanylate cyclase activation by large amounts (50 microL) of saturated amyl nitrite gas did not require, but was enhanced by, the addition of thiols or ascorbate. However, similar to sodium nitrite, guanylate cyclase activation by smaller amounts (5 microL) of saturated amyl nitrite gas did require the addition of one of various thiols or ascorbate. Methylene blue markedly inhibited guanylate cyclase activation by sodium nitrite in the presence of cysteine or ascorbate and similarly inhibited enzyme activation by amyl nitrite either in the absence or presence of cysteine or ascorbate. These data support the hypothesis that nitrates and nitrites relax vascular smooth muscle by stimulating cyclic GMP formation. The results further suggest that, similar to relaxation and guanylate cyclase activation by nitroso-containing compounds, relaxation and enzyme activation by nitrates and and nitrites may involve the formation of nitric oxide or complexes of nitric oxide as active intermediates.
...
PMID:Methylene blue inhibits coronary arterial relaxation and guanylate cyclase activation by nitroglycerin, sodium nitrite, and amyl nitrite. 611 57

A brief review is first presented of findings during the past few years by the authors and by others on the nonprostaglandin endothelium-dependent relaxation of isolated arteries by a large number of vasoactive agents. Among these agents are acetylcholine (ACh); the calcium ionophore A23187; ATP and ADP; substance P; bradykinin (canine, human, and porcine arteries); histamine, acting via an H1-receptor (rat arteries); thrombin (canine arteries); serotonin (canine coronary artery); and norepinephrine, acting via an alpha2-receptor (canine coronary artery). The endothelium-derived relaxing factor (EDRF) released by ACh and other agents has not yet been identified. Our original hypothesis that arachidonic acid is the precursor of EDRF is not supported by the finding that other unsaturated fatty acids in addition to arachidonic acid, and even stearic acid, elicited nonprostaglandin endothelium-dependent relaxations. Methylene blue and hemoglobin (but not methemoglobin) rapidly inhibited relaxation of rabbit aorta by ACh or A23187, suggesting that our proposal that EDRF is a labile free radical may be correct. The endothelium-dependent relaxation by each of these agents was shown to be preceded by an endothelium-dependent increase in cyclic GMP in the smooth muscle--a finding consistent with the hypothesis that EDRF stimulates guanylate cyclase in the muscle, leading to an increase in cyclic GMP that somehow activates relaxation. Some questions relating to the potential physiological important of endothelium-dependent relaxations are discussed.
...
PMID:Endothelial cells as mediators of vasodilation of arteries. 620 42


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---