Oxidative stress increases 6‐nitronorepinephrine and 6‐nitroepinephrine concentrations in rat brain

Abstract

6-Nitronorepinephrine (nitroNE) and 6-nitroepinephrine (nitroE) are reaction products of nitric oxide and norepinephrine and epinephrine, respectively. The authors have previously reported a method for determination of nitroNE and nitroE in rat brain using high-performance liquid chromatography-peroxyoxalate chemiluminescence reaction detection. In this study, the effect of oxidative stress on nitroNE and nitroE concentrations in rat brain was examined using this method. After kainic acid administration in rats for 2 days, the concentrations of both nitroNE and nitroE in rat brains were found to have increased by 400-600%, which was partly suppressed by the co-administration of a superoxide dismutase mimetic. This indicates that oxidative stress might increase nitroNE and nitroE concentrations in rat brains.

Circular Dichroism Spectroscopy Identifies the β-Adrenoceptor Agonist Salbutamol As a Direct Inhibitor of Tau Filament Formation in Vitro

“…However, due to the impaired antioxidant defense system and the increase in reactive oxygen species in neurodegenerative diseases, alternative pathways are triggered, resulting in the production of o -semiquinone, o -quinone, and subsequently nitronorepinephrine species . The latter impedes catechol- o -methyl transferase activity and the neuronal update of norepinephrine, further promoting neurodegeneration . In the absence of the catechol moiety, salbutamol does not undergo the same catalyzed oxidation to o -semiquinone or o -quinone species.…”

“…69 The latter impedes catechol-o-methyl transferase activity and the neuronal update of norepinephrine, further promoting neurodegeneration. 70 In the absence of the catechol moiety, salbutamol does not undergo the same catalyzed oxidation to o-semiquinone or o-quinone species. β 2 -adrenoceptor agonists, such as salbutamol, are primarily metabolized in the airways and gastrointestinal tract by stereoselective sulfate conjugation, leading to an accumulation of the inactive S-enantiomer.…”

Simultaneous determination of dopamine and 3,4-dihydroxyphenylacetic acid in mouse striatum using mixed-mode reversed-phase and cation-exchange high-performance liquid chromatography

“…Since the composition of the mobile phase was changed from that of the previous reports for catecholamines [7,8,16] and nitrocatecholamines [17,18], the conditions of the fluorescence derivatization reaction were re-investigated to obtain the optimum condition. The length of the reaction coil in the flow system at 80 • C was first examined.…”

Chemiluminescence detection with separation techniques for bioanalytical applications

“…As this review specifically focuses on the bioanalytical applications of HPLC-POCL detection, it is worth mentioning that the aforementioned methods significantly contributed to the study of the role of catecholamines [50] and their metabolites [51][52][53] in blood pressure regulation. Nitrocatecholamines, which are obtained from catecholamines in the presence of nitric oxide, in rat brain were determined by HPLC-POCL detection [54,55]. Since nitrocatecholamines have a strong electron-withdrawing nitro group attached to the catechol moiety and nitro aromatic compounds are known to exhibit weak luminescence, reduction of nitrocatecholamines was carried out on a reducing column, the use of which increased the sensitivity of detection by 45-172%.…”