1-3-dihydroxy-4-4-5-5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole and peroxynitric-acid

1-3-dihydroxy-4-4-5-5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole has been researched along with peroxynitric-acid* in 6 studies

Other Studies

6 other study(ies) available for 1-3-dihydroxy-4-4-5-5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole and peroxynitric-acid

ArticleYear
Characterization of the influence of nitric oxide donors on intestinal absorption of macromolecules.
    International journal of pharmaceutics, 2004, Nov-22, Volume: 286, Issue:1-2

    To characterize the influence of nitric oxide (NO) donors on the intestinal absorption of macromolecules, the relationship between the release rate of NO from NO donors and their absorption-enhancing effects and the effects of several scavengers and generators on the absorption-enhancing effects of NO donor were investigated. The t1/2 values of the NO release rate from 3-(2-hydroxy-1-methylethyl-2-nitrosohydrazino)-1-propanamine (NOC5), 3-(2-hydroxy-1-methylethyl-2-nitrosohydrazino)-N-methyl-1-propanamine (NOC7) and N-ethyl-2-(1-ethyl-hydroxy-2-nitrosohydrazino)-ethanamine (NOC12) are 25, 5 and 100min, respectively. The absorption-enhancing effects of NO donors on the absorption of fluorescein isothiocyanate dextrans with an average molecular weight of 4400 (FD-4) are NOC5 > NOC7 > NOC12 in the colon. The lowest enhancing effect of NOC12 may be due to the slow rate of NO release. The enhancing effect of NOC7 rapidly disappeared compared with the effect of NOC5. The results raise the possibility that the difference between NOC5 and NOC7 on enhancing effect is related to the t1/2 of the NO release. The NOC7-induced enhancing effect was prevented by the co-administration of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazole-1-oxyl-3-oxide sodium salt (C-PTIO), an NO scavenger; tiron, an O2(-) scavenger; mannitol, an OH* scavenger, and deferoxamine, peroxynitrate scavenger. Pyrogallol, an O2(-) generator, potentiated the NOC7-induced enhancing effect. These results support a role for peroxynitrate, and possibly OH*, in the NO donor-induced intestinal enhancing effect.

    Topics: 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; Adenosine Triphosphate; Animals; Benzoates; Colon; Dextrans; Drug Synergism; Fluorescein-5-isothiocyanate; Free Radical Scavengers; Hydrazines; Hydroxyl Radical; Imidazoles; Intestinal Absorption; Macromolecular Substances; Male; Nitrates; Nitric Oxide; Nitric Oxide Donors; Nitroso Compounds; Rats; Rats, Wistar; Superoxides; Triazenes

2004
Neuroprotective and neurorescuing effects of isoform-specific nitric oxide synthase inhibitors, nitric oxide scavenger, and antioxidant against beta-amyloid toxicity.
    British journal of pharmacology, 2001, Volume: 133, Issue:7

    Beta amyloid (Abeta) is implicated in Alzheimer's disease (AD). Abeta(1 - 42) (5, 10, or 20 microM) was able to increase NO release and decrease cellular viability in primary rat cortical mixed cultures. L-NOARG and SMTC (both at 10 or 100 microM) - type I NOS inhibitors - reduced cellular NO release in the absence of Abeta(1 - 42). At 100 microM, both drugs decreased cell viability. L-NIL (10 or 100 microM), and 1400W (1 or 5 microM) - type II NOS inhibitors - reduced NO release and improved viability when either drug was administered up to 4 h post Abeta(1 - 42) (10 microM) treatment. L-NOARG and SMTC (both at 10 or 100 microM) were only able to decrease NO release. Carboxy-PTIO or Trolox (both at 10 or 100 microM) - a NO scavenger and an antioxidant, respectively - increased viability when administered up to 1 h post Abeta(1 - 42) treatment. Either L-NIL (50 microM) or 1400W (3 microM) and Trolox (50 microM) showed synergistic actions. Peroxynitrite (100 or 200 microM) reduced cell viability. Viabilities were improved by L-NIL (100 microM), 1400W (5 microM), carboxy-PTIO (10 or 100 microM), and Trolox (10 or 100 microM). Hence, the data show that Abeta(1 - 42) induced NO release in neurons and glial cells, and that Abeta neurotoxicity is, at least in part, mediated by NO. NO concentration modulating compounds and antioxidant may have therapeutic importance in neurological disorders where oxidative stress is likely involved such as in AD.

    Topics: Amyloid beta-Peptides; Animals; Antioxidants; Benzoates; Cell Survival; Cells, Cultured; Cerebral Cortex; Chromans; Citrulline; Dose-Response Relationship, Drug; Enzyme Inhibitors; Imidazoles; Isoenzymes; Lysine; Neuroprotective Agents; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Oxidants; Peptide Fragments; Rats; Rats, Sprague-Dawley; Thiourea; Time Factors

2001
Formation of guanidinosuccinic acid, a stable nitric oxide mimic, from argininosuccinic acid and nitric oxide-derived free radicals.
    Free radical research, 1999, Volume: 31, Issue:1

    Guanidinosuccinic acid (GSA) is noted for its nitric oxide (NO) mimicking actions such as vasodilatation and activation of the N-methyl-D-aspartate (NMDA) receptor. We have reported that GSA is the product of argininosuccinate (ASA) and some reactive oxygen species, mainly the hydroxyl radical. We tested for GSA synthesis in the presence of NO donors. ASA (1 mM) was incubated with NOR-2, NOC-7 or 3-morpholinosydomine hydrochloride (SIN-1) at 37 degrees C. GSA was determined by HPLC using a cationic resin for separation and phenanthrenequinone as an indicator. Neither NOR-2 or NOC-7 formed GSA. SIN-1, on the other hand, generates NO and the superoxide anion which, in turn, generated peroxynitrite which was then converted to the hydroxyl radical. Incubation of ASA with SIN-1 leads, via this route, to GSA. When ASA was incubated with 1 mM SIN-1, the amount of GSA produced depended on the incubation time and the concentration of ASA. Among the tested SIN-1 concentrations, from 0.5 to 5 mM, GSA synthesis was maximum at 0.5 mM and decreased with increasing concentrations of SIN-1. Carboxy-PTIO, a NO scavenger, completely inhibited GSA synthesis. SOD, a superoxide scavenger, decreased GSA synthesis by 20%, and catalase inhibited GSA synthesis only by 12%; DMSO, a hydroxyl radical scavenger completely inhibited GSA synthesis in the presence of SIN-1. These data suggest that the hydroxyl radical derived from a combination of NO and the superoxide anion generates GSA, a stable NO mimic. Meanwhile, synthesis of GSA by NO produces reactive oxygen and activates the NMDA receptor that generates NO from GSA, suggesting a positive feed back mechanism.

    Topics: Argininosuccinic Acid; Benzoates; Chromatography, High Pressure Liquid; Dimethyl Sulfoxide; Feedback; Free Radical Scavengers; Free Radicals; Guanidines; Hydrazines; Hydroxyl Radical; Imidazoles; Molsidomine; Nitrates; Nitric Oxide; Nitric Oxide Donors; Reactive Oxygen Species; Receptors, N-Methyl-D-Aspartate; Succinates; Superoxide Dismutase

1999
Interference of carboxy-PTIO with nitric oxide- and peroxynitrite-mediated reactions.
    Free radical biology & medicine, 1997, Volume: 22, Issue:5

    Carboxy-PTIO reacts rapidly with NO to yield NO2 and has been used as a scavenger to test the importance of nitric oxide (NO) in various physiological conditions. This study investigated the effects of carboxy-PTIO on several NO- and peroxynitrite-mediated reactions. The scavenger potently inhibited NO-induced accumulation of cGMP in endothelial cells but potentiated the effect of the putative peroxynitrite donor SIN-1, Carboxy-PTIO completely inhibited peroxynitrite-induced formation of 3-nitrotyrosine from free tyrosine (EC50 = 36 +/- 5 microM) as well as nitration of bovine serum albumin. Peroxynitrite-mediated nitrosation of GSH was stimulated by the drug with an EC50 of 0.12 +/- 0.03 mM, whereas S-nitrosation induced by the NO donor DEA/NO (0.1 mM) was inhibited by the scavenger with an IC50 of 0.11 +/- 0.03 mM. Oxidation of NO with carboxy-PTIO resulted in formation of nitrite without concomitant production of nitrate. Our results demonstrate that the effects of carboxy-PTIO are diverse and question its claimed specificity as NO scavenger.

    Topics: Animals; Benzoates; Cattle; Cells, Cultured; Cyclic GMP; Endothelium, Vascular; Free Radical Scavengers; Imidazoles; Kinetics; Molsidomine; Nitrates; Nitric Oxide; Nitrites; Serum Albumin, Bovine; Swine; Tyrosine

1997
Oxygen-dependent fragmentation of cellular DNA by nitric oxide.
    Free radical research, 1997, Volume: 26, Issue:3

    Although active oxygen species and related metabolites, such as nitric oxide (NO), have been postulated to play important roles in the apoptosis of various cells, a precise mechanism leading to cell death remains to be elucidated. Recently we found that the lifetime of NO depends greatly on the concentration of environmental oxygen and that NO reversibly inhibits mitochondrial respiration and ATP synthesis; the inhibitory effect is stronger at physiologically low oxygen tension than under atmospheric conditions (Arch. Biochem. Biophys. 323, 27-32, 1995). The present work describes the effects of the NO-generating agent, 1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC 18) and oxygen tension on the respiration, ATP synthesis and apoptosis of HL-60 cells. When respiration was inhibited by NOC 18, cellular ATP levels decreased significantly and DNA fragmentation was elicited. Both events were enhanced by decreasing oxygen tension and suppressed by adding NO-trapping agents, such as 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and oxyhemoglobin. The fragmentation of cellular DNA was inhibited in a dose dependent manner by herbimycin A, a tyrosine kinase inhibitor. Fragmentation of the DNA of HL-60 cells was also induced either by peroxynitrite, superoxide or hydroxyl radical by some mechanism which was diminished by lowering the oxygen tension. These results indicated that the decrease in cellular ATP and activation of tyrosine kinase might play important roles in NO-induced apoptosis particularly under physiologically low oxygen tensions.

    Topics: Adenosine Triphosphate; Apoptosis; Benzoates; Benzoquinones; DNA Fragmentation; Enzyme Inhibitors; Free Radicals; HL-60 Cells; Humans; Imidazoles; Lactams, Macrocyclic; Nitrates; Nitric Oxide; Nitrites; Nitroso Compounds; Oxygen; Quinones; Reactive Oxygen Species; Rifabutin

1997
Activation of human neutrophil procollagenase by nitrogen dioxide and peroxynitrite: a novel mechanism for procollagenase activation involving nitric oxide.
    Archives of biochemistry and biophysics, 1997, Jun-15, Volume: 342, Issue:2

    The involvement of nitric oxide (NO) and its reactive intermediates such as nitrogen dioxide (NO2) and peroxynitrite (ONOO-) in the activation of matrix metallo-proteinase was investigated. The human neutrophil procollagenase (matrix metalloproteinase-8) (M(r), 85 kDa) was purified to homogeneity from human neutrophils by using column chromatography. After incubation of human neutrophil procollagenase with various nitrogen oxide-generating systems, collagenolytic activity in each reaction system was measured. In addition, neutrophil collagenase activity was determined by assessment of proteolysis of human alpha 1-protease inhibitor. NO was formed by the propylamine NONOate, and NO2 was generated by oxidation of NO with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO). NO2, formed by NONOate and carboxy-PTIO, and the synthetic ONOO- exhibited strong activation of the procollagenase at 1-20 microM. Significant activation of the procollagenase was observed with use of authentic NO2 gas as well. Constant flux infusion of ONOO- into the procollagenase solution resulted in stronger procollagenase activation than did a bolus addition of ONOO- to the reaction mixture. However, NO showed only weak activating potential under the aerobic (ambient) condition; an NO concentration of more than 10 mM was needed for appreciable activation of the procollagenase. Of considerable importance was the fact that NO participates in activation of the neutrophil collagenase through its conversion to NO2 or ONOO- in human neutrophils. These results suggest that NO2 and ONOO- may be potent activators of human neutrophil procollagenase.

    Topics: alpha 1-Antitrypsin; Benzoates; Collagen; Collagenases; Edetic Acid; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Enzyme Precursors; Humans; Imidazoles; Leukocyte Elastase; Matrix Metalloproteinase 8; Methemoglobin; Neutrophils; Nitrates; Nitric Oxide; Nitrogen Dioxide; Oxyhemoglobins; Phenanthrolines; Tetradecanoylphorbol Acetate; Triazines

1997