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

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

The response to small peptides such as Arg-vasopressin, oxytocin and tachykinins was investigated in cultured porcine aortic endothelial cells. The production of endothelium-derived nitric oxide was assessed indirectly by the accumulation of cyclic GMP, a response that is due to the increased activity of soluble guanylate cyclase of the endothelial cells after release of the mediator. Arg-vasopressin, oxytocin, substance P and physalae-min (an analog of substance P, pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Gly-Leu-Met-NH2) markedly and transiently stimulated the production of cyclic GMP without affecting that of cyclic AMP. Treatment of endothelial cells with either hemoglobin or methylene blue reduced significantly both the basal and stimulated level of cyclic GMP. The production of cyclic GMP evoked by Arg-vasopressin and substance P was inhibited selectively by NG-monomethyl-L-arginine but not by its D-enantiomer. The neurohypophyseal hormones and related peptides stimulated the accumulation of cyclic GMP in a concentration-dependent manner, with the following relative order of potency: oxytocin greater than Lys-vasopressin greater than Arg-vasopressin much greater than [deamino-Cys1, D-Arg8]-vasopressin. The production of cyclic GMP evoked by oxytocin was inhibited selectively by [d(CH2)5, Tyr(OMe)2, Orn8]-vasotocin, an oxytocin antagonist. The production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin was inhibited by [beta-mercapto-beta, beta-cyclopentamethylene-propionyl1, O-Me-Tyr2, Arg8]-vasopressin, a selective V1-receptor antagonist. The moderate production of cyclic GMP evoked by [deamino-Cys1, D-Arg8]-vasopressin was inhibited significantly by the V1-receptor antagonist. The peptide antagonists affected only minimally or not at all the production of cyclic GMP evoked by a donor of nitric oxide, SIN-1 (3-Morpholino-Sydnonimine). These observations indicate that 1) neurohypophyseal hormones and tachykinins stimulate the accumulation of cyclic GMP in cultured porcine aortic endothelial cells by increasing the production of endothelial-derived nitric oxide, which in turn enhances the activity of soluble guanylate cyclase; 2) the production of cyclic GMP in response to oxytocin is due to activation of oxytocinergic receptors; and 3) the production of cyclic GMP evoked by Arg-vasopressin and Lys-vasopressin is due mostly to activation of V1-vasopressinergic receptors.
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PMID:Neurohypophyseal peptides and tachykinins stimulate the production of cyclic GMP in cultured porcine aortic endothelial cells. 217 9

The hypotensive, natriuretic, and diuretic actions of human atrial natriuretic factor-(99-126) (hANF) are accompanied by an elevation of cyclic guanosine monophosphate (cGMP) in plasma and urine. However, the oxidized hANF analogue, human [Met-O110]ANF-(99-126) (Met-O-ANF), has been reported to be unable to increase cGMP (Biochem. Biophys. Res. Commun. 128: 538-546). We employed this oxidized peptide to evaluate the relationship between its biological effects and cGMP generation, with cGMP serving as a marker of the recognized property of ANF to stimulate particulate guanylate cyclase. Met-O-ANF appeared to be a partial agonist, exhibiting a decreasing order of relative potency of hypotensive, vasorelaxant, diuretic, and natriuretic functions compared to hANF. A lower degree of cGMP increases was achieved by this analogue in cultured smooth muscle and endothelial cells. Met-O-ANF doses, which led to a significant increase in diuresis, were neither natriuretic nor accompanied by an increase of urinary cGMP. We were thus able to dissociate the diuretic and natriuretic effects of ANF. High doses of the oxidized analogue were required to elevate cGMP levels in plasma and urine. In isolated kidney fractions, Met-O-ANF's action on cGMP was significantly lower in glomeruli (fivefold less), virtually absent in the collecting duct, yet only slightly different (20% less) in thick ascending limb. Our results indicate that the diuretic and natriuretic effects are exerted at distinct sites, with only the natriuresis being related to an increase of extracellular cGMP. The variability of differential potency of biological and biochemical effects from tissue to tissue of these two forms of human ANF support the notion of the heterogeneity of the ANF effector system.
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PMID:Dissociation of natriuresis and diuresis and heterogeneity of the effector system of atrial natriuretic factor in rats. 253 99

Met-enkephalin (Met-enk) in 10(-9)-10(-7) M concentrations enhanced the extracellular cytotoxicity of polymorphonuclear leukocytes (PMNL) of young adult humans partly by stimulation of the "respiratory burst" in these cells. Meanwhile adenylate cyclase was inhibited and guanylate cyclase was stimulated. All the observed effects were abolished by 10(-5) M naloxone. On the other hand, a positive receptor coupling to adenylate cyclase was found when Met-enk was added in higher (10(-6)-10(-5) M) concentrations to PMNLs. The elevated cAMP level resulted in decreased extracellular cytotoxicity of PMNLs by a naloxone insensitive way. In PMNLs obtained from healthy aged male subjects, Met-enk induced in all of the applied concentrations an increased cAMP level and no change in cGMP level, with subsequent decrease of cytotoxicity, i.e. an impaired negative coupling of naloxone sensitive opiate receptors was detected with aging.
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PMID:Impaired coupling of naloxone sensitive opiate receptors to adenylate cyclase in PMNLs of aged male subjects. 282 49

Treatment of cultured rat vascular smooth muscle cells with human atrial natriuretic peptide (hANP) or Met(O)12hANP caused a similar and marked reduction (approximately 80%) of ANP receptor number (down-regulation). A second challenge with hANP stimulated the accumulation of intracellular cGMP in the down-regulated cells to the same extent as in control cells. These data suggest that ANP receptor sites are functionally heterogenous, the more abundant site being uncoupled from guanylate cyclase but susceptible to down-regulation.
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PMID:Down-regulation of atrial natriuretic peptide receptor and cyclic GMP response in cultured rat vascular smooth muscle cells. 303 38

Endothelial neutral endopeptidase (EC 3.4.24.11, NEP) contributes to the inactivation of vasoactive and inflammatory peptides such as f-Met-Leu-Phe, substance P, atrial natriuretic peptide, and bradykinin. The aim of the present study was to investigate the cellular regulation of NEP expression in human endothelial cells, focusing on the role of cyclic nucleotides and cellular phosphodiesterases (PDE). Activation of adenylate cyclase by forskolin or prostaglandin E1 (PGE1) induced an increase of NEP activity and NEP protein after 24 h of incubation. This effect was mimicked by two activators of protein kinase A, dibutyryl-cAMP and 8-bromo-cAMP. The nonspecific PDE inhibitor, 3-isobutyl-1-methylxanthine (200 microM), increased NEP activity up to 192%. The activator of guanylate cyclase, sodium nitroprusside (SNP), did not affect NEP activity but completely inhibited the 3-isobutyl-1-methylxanthine-mediated increase of NEP activity. The PDE-III inhibitors motapizone (100 microM) and enoximone (100 microM) enhanced NEP activity up to 188% and 213%, the PDE-IV inhibitor rolipram (3 microM) up to 162%, and the combined PDE-III/IV inhibitor zardaverine (1 microM) up to 176% of control values. The present data provide evidence for a cAMP-mediated increase of NEP activity in human endothelial cells.
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PMID:Activation of adenylate cyclase and phosphodiesterase inhibition enhance neutral endopeptidase activity in human endothelial cells. 854 50

It has previously been observed that nitric oxide (NO) and the opioids Met- and Leu-enkephalin contribute to hypoxia-induced pial artery dilation in the newborn pig. The present study was designed to investigate the relationship between NO and opioids in hypoxic pial dilation. Piglets equipped with closed cranial windows were used to measure pial artery diameter and collect cortical periarachnoid cerebrospinal fluid (CSF) for assay of opioids. Sodium nitroprusside (SNP; 10(-8) and 10(-6) M) elicited pial dilation that was blunted by the soluble guanylate cyclase inhibitor LY-83583 (10(-5) M; 10 +/- 1 and 23 +/- 1 vs. 3 +/- 1 and 7 +/- 1% for 10(-8) and 10(-6) M SNP before and after LY-83583, respectively). SNP-induced dilation was accompanied by increased CSF Met-enkephalin, and coadministration of LY-83583 with SNP blocked these increases in CSF opioid concentration (1,144 +/- 59, 2,215 +/- 165, and 3,413 +/- 168 vs. 1,023 +/- 16, 1,040 +/- 18, and 1,059 +/- 29 pg/ml for control and 10(-8) and 10(-6) M SNP before and after LY-83583, respectively). SNP-induced release of CSF Leuenkephalin was also blocked by LY-83583. Similar blunted vascular and biochemical effects of SNP were observed with coadministration of the purported guanosine 3', 5'-cyclic monophosphate (cGMP) antagonist, the phosphorothioate analogue of 8-bromo-cGMP (BrcGMP) [(R)-p-BrcGMP[S]; 10(-5) M]. The cGMP analogue, BrcGMP, elicited dilation that was also accompanied by increased CSF Met- and Leu-enkephalin. Vascular and biochemical effects of BrcGMP were blunted by (R)-p-cGMP[S] and unchanged by LY-83583. Hypoxia-induced pial artery dilation was attenuated by N omega-nitro-L-arginine (L-NNA; 10(-6) M), an NO synthase inhibitor (25 +/- 2 vs. 14 +/- 1%). Hypoxic pial dilation was accompanied by increased CSF Met-enkephalin, and these increases were attenuated by L-NNA (1,137 +/- 60 and 3,491 +/- 133 vs. 927 +/- 25 and 2,052 +/- 160 pg/ml for control and hypoxia before and after L-NNA, respectively). Hypoxia also increased CSF Leuenkephalin, and these CSF changes were similarly attenuated by L-NNA. These data show that cGMP increases CSF Met- and Leu-enkephalin. Furthermore, these data suggest that NO contributes to hypoxic dilation, at least in part, via formation of cGMP and the subsequent release of opioids.
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PMID:Relationship between nitric oxide and opioids in hypoxia-induced pial artery vasodilation. 878 Jan 80

The effects of sodium nitroprusside (SNP), a nitric oxide (NO) donor, on a methionine-enkephalin (Met-E)-induced K+ current recorded from B-cluster neurons in Aplysia cerebral ganglion were investigated with voltage-clamp and pressure ejection techniques. Bath-applied SNP (10-25 microM) reduced the Met-E-induced K+ current in the neurons without affecting the resting membrane conductance and holding current. The inhibitory effects of SNP were reversible. Pretreatment with methylene blue (10 microM), a non-specific inhibitor of guanylate cyclase, and hemoglobin (50 microM), a NO scavenger, decreased the SNP-induced inhibition of the Met-E-induced current. Intracellular injection of 1 mM guanosine 3',5'-cyclic monophosphate (cGMP) or bath-applied 3-isobutyl-1-methylxanthine (IBMX; 50 microM), a nonspecific phosphodiesterase inhibitor, inhibited the Met-E-induced current. Furthermore, 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 1 microM), a more specific inhibitor of NO-stimulated guanylate cyclase, decreased the SNP-induced inhibition of the Met-E-induced current. These results suggest that SNP induces suppression of the Met-E-induced K+ current recorded from B-cluster neurons of Aplysia cerebral ganglion via stimulation of cGMP formation.
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PMID:Inhibition of the Met-enkephalin-induced K+ current in B-cluster neurons of Aplysia by nitric oxide donor. 897 6

Animal and clinical investigations have reported that exposure to hyperbaric O(2) improved the outcome of some reperfusion injuries. Animal studies have suggested that this may be due to an inhibition of leukocyte adherence to injured endothelium. This investigation tested the hypothesis that exposure to hyperbaric O(2) would inhibit beta2-integrin-dependent adherence of human neutrophils. Subjects were exposed to O(2) at partial pressures of up to 3 atmospheres absolute (ATA; 1 ATA = 0.1 MPa) for 45 min, and neutrophil binding to nylon columns and to fibrinogen-coated surfaces was measured. Exposure to O(2) at 2.8 or 3.0 ATA inhibited beta2-integrin-dependent neutrophil adherence but had no effect on the cell-surface expression of beta2-integrins, respiratory burst in response to phorbol ester, or non-beta2-integrin-dependent adherence to plastic plates coated with a fibronectin-like protein. beta2-Integrin adherence was restored by incubating blood with 8-bromoguanosine 3',5'-cyclic monophosphate (cGMP) and hyperbaric O(2) inhibited synthesis of cGMP by neutrophils stimulated with N-formyl-Met-Leu-Phe (FMLP). In studies of cell fractions, the activity of membrane guanylate cyclase was found to be increased by incubation with FMLP as well as by atrial natriuretic peptide (ANP) plus ATP. Hyperbaric O(2) had no effect on the basal activity of soluble or membrane-bound guanylate cyclase. However, hyperbaric O(2) inhibited the function of both the extracellular binding domain of membrane guanylate cyclase as well as intracellular catalytic activity. There are approximately 7,300 membrane guanylate cyclase molecules per cell, based on binding studies with ANP, with a dissociation constant of approximately 450 pM. Hyperbaric O(2) inhibits the function of human neutrophil beta2-integrins by a process linked to impaired synthesis of cGMP.
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PMID:Inhibition of human neutrophil beta2-integrin-dependent adherence by hyperbaric O2. 912 10

This study examined the signaling mechanism involved in the generation of reactive oxygen species (ROS) in human lymphocytes activated by formyl-Met-Leu-Phenylalanine (fMLP; 200 nmol/L) or phorbol-myristate-acetate (PMA; 100 nmol/L). ROS were monitored spectrophotometrically using dichlorofluorescin diacetate. fMLP and PMA significantly increased ROS above the control levels (p<0.05 and 0.001, respectively). These increases were significantly inhibited by catalase, sodium azide, and dimethylsulfoxide but not by superoxide dismutase, suggesting that the ROS apparently included hydrogen peroxide, singlet oxygen and hydroxyl ion but not superoxide anion. PMA-induced responses were reduced by tyrphostin (p<0.01), ST-638 (p<0.05), KN-62 (p<0.001), bisindolylmaleimide (p<0.001), RO-31-8220 (p<0.001), and by LY-83583 (p<0.001), suggesting significant involvement of tyrosine kinase, calcium/calmodulin kinase II, protein kinase C and guanylyl cyclase. fMLP-induced responses were significantly reduced by only tyrphostin (p<0.001), ST-638 (p<0.05), and KN-62 (p<0.01). The results show that tyrosine kinase and calcium/calmodulin kinase II are common signalling components in the production of reactive oxygen species in activated lymphocytes.
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PMID:Tyrosine and calcium/calmodulin kinases are common signaling components in the generation of reactive oxygen species in human lymphocytes. 1057 66

Nitration of unsaturated fatty acids such as linoleate by NO-derived reactive species forms novel derivatives (including nitrolinoleate [LNO2]) that can stimulate smooth muscle relaxation and block platelet activation by either NO/cGMP or cAMP-dependent mechanisms. Here, LNO2 was observed to inhibit human neutrophil function. LNO2, but not linoleic acid or the nitrated amino acid 3-nitrotyrosine, dose-dependently (0.2 to 1 micromol/L) inhibited superoxide (O2*-) generation, Ca2+ influx, elastase release, and CD11b expression in response to either phorbol 12-myristate 13-acetate or N-formyl-Met-Leu-Phe. LNO2 did not elevate cGMP, and inhibition of guanylate cyclase by 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one did not restore neutrophil responses, ruling out a role for NO. In contrast, LNO2 caused elevations in intracellular cAMP in the presence and absence of phosphodiesterase inhibition, suggesting activation of adenylate cyclase. Compared with phorbol 12-myristate 13-acetate-activated neutrophils, N-formyl-Met-Leu-Phe-activated neutrophils were more susceptible to the inhibitory effects of LNO2, indicating that LNO2 may inhibit signaling both upstream and downstream of protein kinase C. These data suggest novel signaling actions for LNO2 in mediating its potent inhibitory actions. Thus, nitration of lipids by NO-derived reactive species yields products with antiinflammatory properties, revealing a novel mechanism by which NO-derived nitrated biomolecules can influence the progression of vascular disease.
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PMID:Nitrolinoleate inhibits superoxide generation, degranulation, and integrin expression by human neutrophils: novel antiinflammatory properties of nitric oxide-derived reactive species in vascular cells. 1221 83


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