1
|
Shami PJ. Development of JS-K, a First-in-Class Arylated Diazeniumdiolate, for the Treatment of Cancer. Crit Rev Oncog 2023; 28:57-62. [PMID: 37824387 DOI: 10.1615/critrevoncog.2023048725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Affiliation(s)
- Paul J Shami
- Department of Medicine, Division of Hematology and Hematologic Malignancies, Huntsman Cancer Institute, 2000 Circle of Hope, Suite 2100, University of Utah, Salt Lake City
| |
Collapse
|
2
|
Xavier FE. Nitrergic perivascular innervation in health and diseases: Focus on vascular tone regulation. Acta Physiol (Oxf) 2020; 230:e13484. [PMID: 32336027 DOI: 10.1111/apha.13484] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
For a long time, the vascular tone was considered to be regulated exclusively by tonic innervation of vasoconstrictor adrenergic nerves. However, accumulating experimental evidence has revealed the existence of nerves mediating vasodilatation, including perivascular nitrergic nerves (PNN), in a wide variety of mammalian species. Functioning of nitrergic vasodilator nerves is evidenced in several territories, including cerebral, mesenteric, pulmonary, renal, penile, uterine and cutaneous arteries. Nitric oxide (NO) is the main neurogenic vasodilator in cerebral arteries and acts as a counter-regulatory mechanism for adrenergic vasoconstriction in other vascular territories. In the penis, NO relaxes the vascular and cavernous smooth muscles leading to penile erection. Furthermore, when interacting with other perivascular nerves, NO can act as a neuromodulator. PNN dysfunction is involved in the genesis and maintenance of vascular disorders associated with arterial and portal hypertension, diabetes, ageing, obesity, cirrhosis and hormonal changes. For example defective nitrergic function contributes to enhanced sympathetic neurotransmission, vasoconstriction and blood pressure in some animal models of hypertension. In diabetic animals and humans, dysfunctional nitrergic neurotransmission in the corpus cavernosum is associated with erectile dysfunction. However, in some vascular beds of hypertensive and diabetic animals, an increased PNN function has been described as a compensatory mechanism to the increased vascular resistance. The present review summarizes current understanding on the role of PNN in control of vascular tone, its alterations under different conditions and the associated mechanisms. The knowledge of these changes can serve to better understand the mechanisms involved in these disorders and help in planning new treatments.
Collapse
Affiliation(s)
- Fabiano E. Xavier
- Departamento de Fisiologia e Farmacologia Centro de Biociências Universidade Federal de Pernambuco Recife Brazil
| |
Collapse
|
3
|
|
4
|
Toda N, Okamura T. Recent advances in research on nitrergic nerve-mediated vasodilatation. Pflugers Arch 2014; 467:1165-78. [PMID: 25339222 DOI: 10.1007/s00424-014-1621-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 09/25/2014] [Accepted: 09/29/2014] [Indexed: 12/29/2022]
Abstract
Cerebral vascular resistance and blood flow were widely considered to be regulated solely by tonic innervation of vasoconstrictor adrenergic nerves. However, pieces of evidence suggesting that parasympathetic nitrergic nerve activation elicits vasodilatation in dog and monkey cerebral arteries were found in 1990. Nitric oxide (NO) as a neurotransmitter liberated from parasympathetic postganglionic neurons decreases cerebral vascular tone and resistance and increases cerebral blood flow, which overcome vasoconstrictor responses to norepinephrine liberated from adrenergic nerves. Functional roles of nitrergic vasodilator nerves are found also in peripheral vasculature, including pulmonary, renal, mesenteric, hepatic, ocular, uterine, nasal, skeletal muscle, and cutaneous arteries and veins; however, adrenergic nerve-induced vasoconstriction is evidently greater than nitrergic vasodilatation in these vasculatures. In coronary arteries, neurogenic NO-mediated vasodilatation is not clearly noted; however, vasodilatation is induced by norepinephrine released from adrenergic nerves that activates β1-adrenoceptors. Impaired actions of NO liberated from the endothelium and nitrergic neurons are suggested to participate in cerebral hypoperfusion, leading to brain dysfunction, like that in Alzheimer's disease. Nitrergic neural dysfunction participates in impaired circulation in peripheral organs and tissues and also in systemic blood pressure increase. NO and vasodilator peptides, as sensory neuromediators, are involved in neurogenic vasodilatation in the skin. Functioning of nitrergic vasodilator nerves is evidenced not only in a variety of mammals, including humans and monkeys, but also in non-mammals. The present review article includes recent advances in research on the functional importance of nitrergic nerves concerning the control of cerebral blood flow, as well as other regions, and vascular resistance. Although information is still insufficient, the nitrergic nerve histology and function in vasculatures of non-mammals are also summarized.
Collapse
Affiliation(s)
- Noboru Toda
- Toyama Institute for Cardiovascular Pharmacology Research, 7-13, 1-Cho-me, Azuchi-machi, Chuo-ku, Osaka, 541-0052, Japan,
| | | |
Collapse
|
5
|
Subedi H, Hassanin HA, Brasch NE. Kinetic and Mechanistic Studies on the Reaction of the Vitamin B12 Complex Aquacobalamin with the HNO Donor Angeli’s Salt: Angeli’s Salt and HNO React with Aquacobalamin. Inorg Chem 2014; 53:1570-7. [DOI: 10.1021/ic402613z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | - Hanaa A. Hassanin
- Department
of Chemistry, Ain Shams University, Abbassia Square, Cairo, 11566, Egypt
| | | |
Collapse
|
6
|
Subedi H, Brasch NE. Mechanistic Studies on the Reaction of Nitroxylcobalamin with Dioxygen: Evidence for Formation of a Peroxynitritocob(III)alamin Intermediate. Inorg Chem 2013; 52:11608-17. [DOI: 10.1021/ic401975f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Harishchandra Subedi
- Department of Chemistry and Biochemistry and ‡School of Biomedical
Sciences, Kent State University, Kent, Ohio 44242, United States
| | - Nicola E. Brasch
- Department of Chemistry and Biochemistry and ‡School of Biomedical
Sciences, Kent State University, Kent, Ohio 44242, United States
| |
Collapse
|
7
|
Walker DT, Dassanayake RS, Garcia KA, Mukherjee R, Brasch NE. Mechanistic Studies on the Reaction of Nitrocobalamin with Glutathione: Kinetic evidence for formation of an aquacobalamin intermediate. Eur J Inorg Chem 2013; 2013:10.1002/ejic.201300254. [PMID: 24415907 PMCID: PMC3885173 DOI: 10.1002/ejic.201300254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Indexed: 11/09/2022]
Abstract
The essential but also toxic gaseous signaling molecule nitric oxide is scavenged by the reduced vitamin B12 complex cob(II)alamin. The resulting complex, nitroxylcobalamin (NO--Cbl(III)), is rapidly oxidized to nitrocobalamin (NO2Cbl) in the presence of oxygen; however it is unlikely that nitrocobalamin is itself stable in biological systems. Kinetic studies on the reaction between NO2Cbl and the important intracellular antioxidant, glutathione (GSH), are reported. In this study, a reaction pathway is proposed in which the β-axial ligand of NO2Cbl is first substituted by water to give aquacobalamin (H2OCbl+), which then reacts further with GSH to form glutathionylcobalamin (GSCbl). Independent measurements of the four associated rate constants k1, k-1, k2, and k-2 support the proposed mechanism. These findings provide insight into the fundamental mechanism of ligand substitution reactions of cob(III)alamins with inorganic ligands at the β-axial site.
Collapse
Affiliation(s)
- David T. Walker
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Rohan S. Dassanayake
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Kamille A. Garcia
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Riya Mukherjee
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Nicola E. Brasch
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| |
Collapse
|
8
|
Hassanin HA, El-Shahat MF, DeBeer S, Smith CA, Brasch NE. Redetermination of the X-ray structure of nitroxylcobalamin: base-on nitroxylcobalamin exhibits a remarkably long Co-N(dimethylbenzimidazole) bond distance. Dalton Trans 2010; 39:10626-30. [PMID: 20890534 DOI: 10.1039/c0dt00628a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The X-ray structures of three new crystals of nitroxylcobalamin (NOCbl) have been determined. Unlike our earlier reported structure in which NOCbl was partially oxidized (L. Hannibal, C. A. Smith, D. W. Jacobsen and N. E. Brasch, Angew. Chem., Int. Ed. 2007, 46, 5140), the O atom of the nitroxyl ligand is located in a single position with a N=O bond distance of 1.12-1.14 Å, consistent with a double bond. The Co-N-O angle is in the 118.9-120.3 Å range. The α-axial Co-N(dimethylbenzimidazole) (Co-NB3) bond distance is a remarkable 2.32-2.35 Å in length, ~0.1 Å longer than that reported for all other cobalamin structures. The change in the Gibbs free energy for the base-on/base-off equilibrium now correlates extremely well with the Co-NB3 bond distance, as observed for other cobalamins.
Collapse
Affiliation(s)
- Hanaa A Hassanin
- Department of Chemistry, Kent State University, Kent, OH 44242, USA
| | | | | | | | | |
Collapse
|
9
|
Hassanin HA, Hannibal L, Jacobsen DW, Brown KL, Marques HM, Brasch NE. NMR spectroscopy and molecular modelling studies of nitrosylcobalamin: further evidence that the deprotonated, base-off form is important for nitrosylcobalamin in solution. Dalton Trans 2009:424-33. [PMID: 19122899 PMCID: PMC2754767 DOI: 10.1039/b810895a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structure of nitrosylcobalamin (NOCbl) in solution has been studied by NMR spectroscopy and the 1H and 13C NMR spectra have been assigned. 13C and 31P NMR chemical shifts, the UV-vis spectrum of NOCbl and the observed pKbase-off value of approximately 5.1 for NOCbl provide evidence that a significant fraction of NOCbl is present in the base-off, 5,6-dimethylbenzimidazole (DMB) deprotonated, form in solution. NOE-restrained molecular mechanics modelling of base-on NOCbl gave annealed structures with minor conformational differences in the flexible side chains and the nucleotide loop position compared with the X-ray structure. A molecular dynamics simulation at 300 K showed that DMB remains in close proximity to the alpha face of the corrin in the base-off form of NOCbl. Simulated annealing calculations produced two major conformations of base-off NOCbl. In the first, the DMB is perpendicular to the corrin and its B3 nitrogen is about 3.1 A away from and pointing directly at the metal ion; in the second the DMB is parallel to and tucked beneath the D ring of the corrin.
Collapse
Affiliation(s)
- Hanaa A. Hassanin
- Department of Chemistry, School of Biomedical Sciences, Kent State University, Kent, OH44242
| | - Luciana Hannibal
- Department of Chemistry, School of Biomedical Sciences, Kent State University, Kent, OH44242
- School of Biomedical Sciences, Kent State University, Kent, OH 44242. E-mail:
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Donald W. Jacobsen
- School of Biomedical Sciences, Kent State University, Kent, OH 44242. E-mail:
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44106
| | - Kenneth L. Brown
- Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701
| | - Helder M. Marques
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Wits, Johannesburg, 2050, South Africa. E-mail:
| | - Nicola E. Brasch
- Department of Chemistry, School of Biomedical Sciences, Kent State University, Kent, OH44242
- School of Biomedical Sciences, Kent State University, Kent, OH 44242. E-mail:
| |
Collapse
|
10
|
Gerth K, Ehring T, Braendle M, Schelling P. Nitric Oxide Scavenging by Hydroxocobalamin May Account for Its Hemodynamic Profile. Clin Toxicol (Phila) 2008; 44 Suppl 1:29-36. [PMID: 16990191 DOI: 10.1080/15563650600811805] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Antidotal doses of hydroxocobalamin are associated with transient increases in blood pressure in some animals and humans. These studies in anesthetized rabbits were undertaken to explore the possible mechanisms underlying the hemodynamic effects of hydroxocobalamin by investigating 1) possible hemodynamic effects of cyanocobalamin, which is formed on a molar-to-molar basis when hydroxocobalamin binds cyanide, and 2) the interference of hydroxocobalamin with the endothelial nitric oxide system. METHODS Study 1 investigated the hemodynamic effects of cyanocobalamin. This study included two treatment arms: 1) cyanocobalamin (75 mg/kg, IV) followed by saline (n = 7) and 2) saline followed by cyanocobalamin (n = 7). Study 2 assessed the hemodynamic effects of hydroxocobalamin (75 mg/kg, IV) in the presence and absence of the nitric oxide synthase inhibitor L-Nomega-nitro-L-arginine methyl ester (L-NAME; 30 mg/kg, IV). Nitric oxide synthase inhibition itself increases blood pressure. Thus, as part of Study 2, the hemodynamic effects of hydroxocobalamin were also investigated in the presence of an equipressor dose of angiotensin II (ANGII; 0.05 microg/kg/min, IV) in order to determine whether elevated blood pressure per se could interfere with hydroxocobalamin's hemodynamic effects. This study included six treatment arms (designated as first treatment + second treatment): saline + saline (n = 5), L-NAME + saline (n = 7), saline + hydroxocobalamin (n = 7), L-NAME + hydroxocobalamin (n = 7), ANGII + hydroxocobalamin (n = 7), and ANGII + saline (n = 7). RESULTS In Study 1, the effects of cyanocobalamin on hemodynamic parameters were indistinguishable from those of saline. In Study 2, hydroxocobalamin infusion was associated with moderate hemodynamic effects, including an increase in systemic vascular resistance, an increase in blood pressure, and a decrease in cardiac output. Administration of L-NAME abolished the effects of hydroxocobalamin on all hemodynamic parameters. ANGII at a dose producing a pressor response comparable to that of L-NAME did not influence the hydroxocobalamin-associated hemodynamic changes. CONCLUSION These studies in anesthetized rabbits demonstrate that the moderate pressor effect of hydroxocobalamin is not related to the formation of cyanocobalamin but is very likely related to the scavenging of nitric oxide by hydroxocobalamin.
Collapse
|
11
|
Hannibal L, Smith CA, Jacobsen DW, Brasch NE. Nitroxylcob(III)alamin: synthesis and X-ray structural characterization. Angew Chem Int Ed Engl 2007; 46:5140-3. [PMID: 17542034 PMCID: PMC2764306 DOI: 10.1002/anie.200701131] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luciana Hannibal
- Department of Chemistry and School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | | | | | | |
Collapse
|
12
|
Hannibal L, Smith C, Jacobsen D, Brasch N. Nitroxylcob(III)alamin: Synthesis and X-ray Structural Characterization. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701131] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
13
|
Bonaventura D, Oliveira FS, Lunardi CN, Vercesi JA, da Silva RS, Bendhack LM. Characterization of the mechanisms of action and nitric oxide species involved in the relaxation induced by the ruthenium complex. Nitric Oxide 2007; 15:387-94. [PMID: 16769232 DOI: 10.1016/j.niox.2006.04.260] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 04/12/2006] [Accepted: 04/22/2006] [Indexed: 10/24/2022]
Abstract
Nitric oxide (NO) plays an important role in the control of vascular tone. NO donors have therapeutic use and the most used NO donors, nitroglycerin and sodium nitroprusside have problems in their use. Thus, new NO donors have been synthesized to minimize these undesirable effects. Nytrosil ruthenium complexes have been studied as a new class of NO donors. trans-[RuCl([15]aneN(4))NO](2+), induces vasorelaxation only in presence of reducing agent. In this study, we characterized the mechanisms of vasorelaxation of trans-[RuCl([15]aneN(4))NO](2+) in denuded rat aorta and identified which NO forms are involved in this relaxation. We also evaluated the effect of this NO donor in decreasing the cytosolic Ca(2+) concentration ([Ca(2+)]c) of the vascular smooth muscle cells. Vasorelaxation to trans-[RuCl([15]aneN(4))NO](2+) (E(max): 101.8 +/- 2.3%, pEC(50): 5.03 +/- 0.15) was almost abolished in the presence of the NO* scavenger hydroxocobalamin (E(max): 4.0 +/- 0.4%; P < 0.001) and it was partially inhibited by the NO(-) scavenger L-cysteine (E(max): 79.9 +/- 6.9%, pEC(50): 4.41 +/- 0.06; P < 0.05). The guanylyl cyclase inhibitor ODQ reduced the E(max) (57.7 +/- 4.0%, P < 0.001) and pEC(50) (4.21 +/- 0.42, P < 0.01) and the combination of ODQ and TEA abolished the response to trans-[RuCl([15]aneN(4))NO](2+). The blockade of voltage-dependent (K(v)), ATP-sensitive (K(ATP)), and Ca(2+)-activated (K(Ca) K(+) channels reduced the vasorelaxation induced by trans-[RuCl([15]aneN(4))NO](2+). This compound significantly reduced [Ca(2+)]c (from 100% to 85.9 +/- 3.5%, n = 4). In conclusion, our data demonstrate that this NO donor induces vascular relaxation involving NO* and NO(-) species, that is associated to a decrease in [Ca(2+)]c. The mechanisms of vasorelaxation involve guanylyl cyclase activation, cGMP production and K(+) channels activation.
Collapse
Affiliation(s)
- Daniella Bonaventura
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, USP, Ribeirão Preto 14.040-903, SP, Brazil
| | | | | | | | | | | |
Collapse
|
14
|
Udupi V, Yu M, Malaviya S, Saavedra JE, Shami PJ. JS-K, a nitric oxide prodrug, induces cytochrome c release and caspase activation in HL-60 myeloid leukemia cells. Leuk Res 2006; 30:1279-83. [PMID: 16439016 DOI: 10.1016/j.leukres.2005.12.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 12/15/2005] [Accepted: 12/20/2005] [Indexed: 10/25/2022]
Abstract
Nitric oxide (NO) induces differentiation and apoptosis in acute myelogenous leukemia (AML) cells. The NO prodrug O2-(2,4-dinitrophenyl)1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate, or JS-K, has potent antileukemic activity. JS-K induces apoptosis in HL-60 cells by a caspase-dependent mechanism. The purpose of this study was to determine the pathway through which JS-K induces apoptosis. We show that JS-K alters mitochondrial membrane potential (DeltaPsim) and induces cytochrome c release from mitochondria into the cytoplasm. Treatment with JS-K resulted in activation of Caspase (Casp) 9, Casp 3 and Casp 8. JS-K constitutes a promising lead for a new class of anti-leukemic agents.
Collapse
Affiliation(s)
- Vidya Udupi
- Medical Oncology, University of Utah, Salt Lake City, UT, USA
| | | | | | | | | |
Collapse
|
15
|
Guigonis V, Frémeaux-Bacchi V, Giraudier S, Favier R, Borderie D, Massy Z, Mougenot B, Rosenblatt DS, Deschênes G. Late-onset thrombocytic microangiopathy caused by cblC disease: association with a factor H mutation. Am J Kidney Dis 2005; 45:588-95. [PMID: 15754282 DOI: 10.1053/j.ajkd.2004.12.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND cblC disease is a cause of hemolytic uremic syndrome (HUS), which has been primarily described in neonates and infants with severe renal and neurological lesions. PATIENTS Two sisters aged 6 and 8.5 years presented with a latent hemolytic process characterized by undetectable or low plasma haptoglobin, respectively, associated with renal failure and gross proteinuria. Renal biopsies performed in both patients found typical findings of thrombotic microangiopathy suggesting the diagnosis of HUS. Both patients were free of neurologic signs. RESULTS Biochemical investigations found a cobalamin processing deficiency of the cblC type. Search for additional factors susceptible to worsen endothelial damage revealed homozygosity 677C--> T mutation in the methylenetetrahydrofolate reductase gene as well as heterozygosity for a 3254T--> C mutation in factor H in the patient with the most severe clinical presentation. Long-term subcutaneous administration of hydroxocobalamin in combination with oral betaine and folic acid resulted in clinical and biological improvement in both patients. CONCLUSION cblC disease may be a cause of chronic HUS with delayed onset in childhood. Superimposed mutation of factor H gene might influence clinical severity.
Collapse
Affiliation(s)
- Vincent Guigonis
- Department of Pediatric Nephrology, Hôpital Armand-Trousseau, Paris, France
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
UV-vis stopped-flow results show that glutathionylcobalamin can react with nitric oxide at pH 7 to form nitrosylcob(II)alamin in a reaction second-order overall. From kinetic studies we suggest that nitric oxide attacks glutathionylcobalamin to form a caged transition state followed by formation of the nitrosylcob(II)alamin.
Collapse
Affiliation(s)
- Donghong Zheng
- Department of Chemistry and Center for Analysis of Structures and Interfaces (CASI), The City College of New York, and The Graduate School and University Center of The City University of New York, New York, New York 10031, USA
| | | |
Collapse
|
17
|
Ellis A, Lu H, Li CG, Rand MJ. Effects of agents that inactivate free radical NO (NO*) on nitroxyl anion-mediated relaxations, and on the detection of NO* released from the nitroxyl anion donor Angeli's salt. Br J Pharmacol 2001; 134:521-8. [PMID: 11588105 PMCID: PMC1572981 DOI: 10.1038/sj.bjp.0704287] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. The effects of agents that inactivate free radical nitric oxide (carboxy-PTIO, hydroxocobalamin and pyrogallol) were tested on relaxations produced by the nitroxyl anion (NO(-)) donor Angeli's salt in rat aortic rings and anococcygeus muscles. The amount of NO(*) generated from Angeli's salt in the presence of these agents was measured using a NO(*)-selective electrode sensor. 2. Carboxy-PTIO (100, 300 microM), hydroxocobalamin (30, 100 microM) and pyrogallol (10, 30 microM) significantly reduced relaxations produced by Angeli's salt (0.3 microM) in aortic rings but not in anococcygeus muscles. 3. NO(*) generated from Angeli's salt (0.1 - 10 microM), as detected by the sensor electrode, was less than 0.5% of the amount of Angeli's salt added. Carboxy-PTIO (100 microM) and hydroxocobalamin (30 microM), but not pyrogallol significantly increased the amount of NO(*) detected. 4. In the presence of an oxidizing agent copper [II] (as CuSO(4) 100 microM), the amount of NO(*) detected from 0.3 microM of Angeli's salt increased from an undetectable level of 142.7+/-15.7 nM (equivalent to 47.6% of Angeli's salt added). Under these conditions, carboxy-PTIO, hydroxocobalamin and pyrogallol significantly reduced the amount of NO(*) detected from Angeli's salt as well as the signal generated by an equivalent amount of authentic NO (0.33 microM). 5. The difference in effects of these agents on relaxations to Angeli's salt in the aorta and the anococcygeus muscle may be explained by the ready conversion of NO(-) to NO(*) in the aorta through an unidentified mechanism, which makes NO(-) susceptible to inactivation by these agents. Furthermore, in addition to inactivating NO(*), carboxy-PTIO and hydroxocobalamin may themselves oxidize NO(-) to NO(*), albeit slightly.
Collapse
Affiliation(s)
- Anthie Ellis
- Drug Research & Development Group, School of Medical Sciences, RMIT University, P.O. Box 71, Bundoora West, Victoria 3083, Australia
| | - Hong Lu
- Drug Research & Development Group, School of Medical Sciences, RMIT University, P.O. Box 71, Bundoora West, Victoria 3083, Australia
| | - Chun Guang Li
- Drug Research & Development Group, School of Medical Sciences, RMIT University, P.O. Box 71, Bundoora West, Victoria 3083, Australia
- Author for correspondence:
| | - Michael J Rand
- Drug Research & Development Group, School of Medical Sciences, RMIT University, P.O. Box 71, Bundoora West, Victoria 3083, Australia
| |
Collapse
|
18
|
Li CG, Rand MJ. Effects of hydroxocobalamin and carboxy-PTIO on nitrergic transmission in porcine anococcygeus and retractor penis muscles. Br J Pharmacol 1999; 127:172-6. [PMID: 10369470 PMCID: PMC1565983 DOI: 10.1038/sj.bjp.0702496] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The effects of carboxy-PTIO and hydroxocobalamin were studied on nitrergic transmission in anococcygeus and retractor penis muscles taken during post mortem examination from young male pigs. In both muscles under resting conditions, electrical field stimulation (EFS) caused contractions that were sensitive to tetrodotoxin (1 microM) and were greatly inhibited by prazosin (1 microM) and guanethidine (10-30 microM), but were not significantly affected by atropine (1 microM). In the anococcygeus muscle, but not in the retractor penis muscle, guanethidine produced a prolonged contraction. After tone was raised by guanethidine in the anococcygeus or by phenylephrine (1 microM) in the presence of guanethidine in the retractor penis, EFS caused tetrodotoxin-sensitive relaxations. The EFS-induced relaxations were abolished by the NO synthase inhibitor N(G)-L-nitro-arginine methyl ester (L-NAME; 100 microM) and its effect was partly overcome by L-arginine (1 mM), indicating it was mediated by nitrergic nerves. Carboxy-PTIO (0.1-1 mM) had no significant effect in reducing stimulation-induced nitrergic relaxations in either muscle. However, hydroxocobalamin (0.1-1 mM) caused concentration-dependent reductions of nitrergic relaxations in both muscles. Relaxations to exogenous nitric oxide (1 microM) in both muscles were abolished by carboxy-PTIO (0.3 mM) and hydroxocobalamin (0.1 mM). There were no differences in reactivity to carboxy-PTIO or hydroxocobalamin between anococcygeus and retractor penis muscles from the same species (pig). The finding also confirms earlier observations that the nitrergic transmitter is generally resistant to the NO-scavenger carboxy-PTIO.
Collapse
Affiliation(s)
- C G Li
- Pharmacology Research Unit, Department of Medical Laboratory Science, RMIT University, Victoria 3001, Australia
- Author for correspondence:
| | - M J Rand
- Pharmacology Research Unit, Department of Medical Laboratory Science, RMIT University, Victoria 3001, Australia
| |
Collapse
|