Nitric Oxide Reactions Important to Biological Systems: A Survey of Some Kinetics Investigations

doi:10.1006/meth.1995.1003

Methods

Volume 7, Issue 1, February 1995, Pages 14-20

https://doi.org/10.1006/meth.1995.1003 Get rights and content

Abstract

This report will summarize some kinetic investigations of different reactions involving nitric oxide (NO) that are potentially relevant to biological chemistry. Such studies should provide a quantitative understanding of possible pathways in which NO may participate. On the basis of this information, it should be possible to determine the most significant pathways among the multitude of chemical trajectories that must be considered in interpreting biological systems. The principal focus will be on nitric oxide autoxidation, although related reactions of NO with various radicals and metal complexes will also be discussed.

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Cited by (42)

Study of a gold electrode modified by trans-[Ru(NH<inf>3</inf>) <inf>4</inf>(Ist)SO<inf>4</inf>]<sup>+</sup> to produce an electrochemical sensor for nitric oxide
2011, Electrochimica Acta
Citation Excerpt :
In addition, while the importance of investigating drugs that act as NO donors is well recognized, the NO molecule is unstable, presenting a short half-life of 0.1–6 s [7]. Furthermore, the mechanism and extent of dissociation from NO donors is not fully understood, and such compounds are sometimes unstable with respect to temperature and light [8]. As a consequence, there is considerable interest in kinetically and thermodynamically stable compounds that can, with minimal toxic effects, release or scavenge NO in vivo.
The modification of a gold electrode surface by electropolymerization of trans-[Ru(NH₃)₄(Ist)SO₄]⁺ to produce an electrochemical sensor for nitric oxide was investigated. The influence of dopamine, serotonin and nitrite as interferents for NO detection was also examined using square-wave voltammetry (SWV). The characterization of the modified electrode was carried out by cyclic voltammetry, electrochemical quartz crystal microbalance (EQCM) and SERS techniques. The gold electrode was successfully modified by the trans-[Ru(NH₃)₄(Ist)SO₄]⁺ complex ion using cyclic voltammetry. The experiments show that a monolayer of the film is achieved after ten voltammetric cycles, that NO in solution can coordinate to the metal present in the layer, that dopamine, serotonin and nitrite are interferents for the detection of NO, and that the response for the nitrite is much less significant than the responses for dopamine and serotonin. The proposed modified electrode has the potential to be applied as a sensor for NO.
Neuroprotective effect of aminoguanidine on iron-induced neurotoxicity
2008, Brain Research Bulletin
Iron is a commonly used metal to induce neuronal hyperactivity and oxidative stress. Iron levels rise in the brain in some neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. A body of evidence indicates a link between neuronal death and nitric oxide. The present study was performed to investigate whether nitric oxide produced by inducible nitric oxide synthase is involved in iron-induced neuron death. For this purpose rats were divided into four groups: control, iron, aminoguanidine and iron + aminoguanidine. Animals in iron and iron + aminoguanidine groups received intracerebroventricular FeCl₃ injection (200 mM, 2.5 μl). Rats belonging to control and aminoguanidine groups received the same amount of saline into the cerebral ventricles. All animals were kept alive for 10 days following the operation and animals in aminoguanidine and iron + aminoguanidine groups received intraperitoneal aminoguanidine injections once a day (100 mg/kg day) during this period. After 10 days, rats were perfused intracardially under deep urethane anesthesia. Removed brains were processed using the standard histological techniques. The total numbers of neurons in hippocampus of all rats were estimated with the unbiased stereological techniques. It was found that aminoguanidine decreased mean neuron loss from 43.4% to 20.3%. Results of the present study suggest that aminoguanidine may attenuate the neurotoxic effects of iron by inhibiting inducible nitric oxide synthase.
The challenge of real-time measurements of nitric oxide release in the brain
2006, Autonomic Neuroscience: Basic and Clinical
Nitric oxide (NO) acts as a signalling molecule in the brain. NO has been implicated in a variety of central functions such as learning, plasticity and neurodegeneration. It is also involved in regulation of autonomic homeostasis at different levels of neuraxis including the nucleus tractus solitarii. In spite of the ample evidence for NO-mediated signalling many aspects of its mechanism of action the brain remain unknown largely due to the difficulties of NO detection in real time coupled with its unique ability to freely cross cellular membranes. Here we give a brief overview of the currently available options for NO detection in the brain (such as electrochemistry, fluorescent indicators, electron-paramagnetic resonance) and consider some of their limitations. We conclude that it would be extremely useful to develop a highly sensitive probe for NO detection with some kind of build-in amplification which would magnify the changes triggered by NO to allow its detection within microdomains of the brain tissue in real time.
Electrochemical activation of electrodes for amperometric detection of nitric oxide
2003, Nitric Oxide - Biology and Chemistry
An open question in the literature of nitric oxide detection was investigated: does electrochemical activation account for the enhanced properties of certain presumed chemically-modified electrodes? Uniform electrodes of graphite, iridium, palladium, platinum, and ruthenium were exposed to potential cycling and then tested for amperometric response to nitric oxide to identify principles that govern electrochemical activation of nitric oxide electrodes. These electrodes were compared to similar electrodes that were not cycled. Only cycled graphite and ruthenium showed significantly increased responses. Graphite demonstrated enhanced performance after exposure to cycling potentials at which oxygen, CO₂, and soluble carbonates form, suggesting that erosion of the electrode enhanced its response by increasing the surface area accessible to nitric oxide. This may explain the performance of carbon fibers cycled to the same potentials in solutions containing metalloporphyrins. The response of ruthenium was enhanced after cycling to less extreme potentials at which soluble species do not form and at which a metallic conductive oxide, RuO₂, could lay down a stable, adherent layer on the electrode surface. Cycled ruthenium also exhibited a much greater increase in capacitance after cycling, consistent with the formation of a conductive surface layer.
In vivo effects of the controlled NO donor/scavenger ruthenium cyclam complexes on blood pressure
2002, Life Sciences
Ruthenium(II/III) complexes able to bind and release NO^• were tested in vivo, in conscious Wistar rats instrumented for continuous blood pressure (BP) measurement and administration of in bolus injections (5 to 100 nmol/Kg i.v.) of trans-[Ru^IICl(NO⁺)(cyclam)](PF₆)₂ (cyclam-NO) or sodium nitroprusside (SNP). For normotensive rats, cyclam-NO produced a sustained 10% BP reduction of basal MAP during 7 ± 0.4 to 11 ± 0.3 min. In acute hypertensive rats, cyclam-NO produced BP reduction 3-fold larger than in normotensive rats and similar to that of SNP (maximal effect: 41 ± 1.3 vs. 45 ± 2.2 mmHg, respectively). However, the duration of the effect of cyclam-NO was 13 to 21-fold longer than that of SNP. The hypotensive effect of cyclam-NO was fully blocked in presence of continuous infusion of a NO^• scavenger, carboxy-PTIO (6 mmol/Kg/min), or of the inhibitor of cGMP activation, methylene blue (83 nmol/Kg/min), or of the cyclam-NO precursor, trans-[RuCl(tfms)(cyclam)](tfms) (cyclam-tfms) (500 mmol/Kg/min). The long lasting BP reduction of cyclam-NO can be interpreted in terms of a slower rate of NO^• release (k_-NO = 2.2 × 10⁻³ s⁻¹ at 35 °C) following chemical reduction (E^0′ = 0.10 V vs NHE). In summary, cyclam-NO showed an hypotensive effect around 20 times longer than SNP in either normotensive or hypertensive rats, which was completely inhibited by methylene blue or carboxy-PTIO. Continuous infusion of cyclam-tfms completely blocked the hypotensive effect of cyclam-NO by scavenging the NO^• released by the reduced cyclam-NO.
Electrochemical detection of physiological nitric oxide: Materials and methods
2002, Methods in Enzymology
Advances in the electroanalytical technology of NO detection make it possible to detect the release of robust concentrations of NO from living systems under pathological or pharmacological conditions. However, technical improvements should enable the construction of research instruments with one or two orders of magnitude improvement in both detection limit and temporal resolution. Such instruments would be capable of revealing physiological NO production and could help quantify the correlations between NO levels and health or disease, ultimately leading to important applications in biomedical research and clinical medicine.

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Regular ArticleNitric Oxide Reactions Important to Biological Systems: A Survey of Some Kinetics Investigations

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Nitric Oxide Reactions Important to Biological Systems: A Survey of Some Kinetics Investigations