AUTHOR=Britto-Júnior José , Furlaneto Rafael , Lima Antonio Tiago , de Oliveira Mariana Gonçalves , Severino Beatrice , Frecentese Francesco , Fiorino Ferdinando , Caliendo Giuseppe , Muscará Marcelo Nicolás , De Nucci Gilberto 

TITLE=GKT137831 and hydrogen peroxide increase the release of 6-nitrodopamine from the human umbilical artery, rat-isolated right atrium, and rat-isolated vas deferens

JOURNAL=Frontiers in Pharmacology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1348876

DOI=10.3389/fphar.2024.1348876

ISSN=1663-9812

ABSTRACT=<p><bold>Introduction:</bold> The human umbilical artery (HUA), rat-isolated right atrium, and rat-isolated vas deferens present a basal release of 6-nitrodopamine (6-ND). The basal release of 6-ND from these tissues was significantly decreased (but not abolished) when the tissues were pre-incubated with N<sup>ω</sup>-nitro-L-arginine methyl ester (L-NAME).</p><p><bold>Methods:</bold> In this study, the effect of the pharmacological modulation of the redox environment on the basal release of 6-ND was investigated. The basal release of 6-ND was measured using Liquid chromatography with tandem mass spectrometry (LC-MS/MS).</p><p><bold>Results and Discussion:</bold> Pre-incubation (30 min) of the tissues with GKT137831 (1 μM) caused a significant increase in the basal release of 6-ND from all tissues. In the HUA, pre-incubation with diphenyleneiodonium (DPI) (100 μM) also caused significant increases in the basal release of 6-ND. Preincubation of the HUA with hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) (100 μM) increased 6-ND basal release, whereas pre-incubation with catalase (1,000 U/mL) significantly decreased it. Pre-incubation of the HUA with superoxide dismutase (SOD) (250 U/mL; 30 min) also significantly increased the basal release of 6-ND. Preincubation of the HUA with either allopurinol (100 μM) or uric acid (1 mM) had no effect on the basal release of 6-ND. Pre-treatment of the HUA with L-NAME (100 μM) prevented the increase in the basal release of 6-ND induced by GKT137831, diphenyleneiodonium, and H<sub>2</sub>O<sub>2</sub>. The results obtained indicate a major role of endogenous H2O2 and peroxidases as modulators of 6- ND biosynthesis/release and a lack of peroxynitrite contribution.</p>