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6-Nitrodopamine is released by human umbilical cord vessels and modulates vascular reactivity

2021; Elsevier BV; Volume: 276; Linguagem: Inglês

10.1016/j.lfs.2021.119425

1879-0631

José Britto‐Júnior, Weverton Castro Coelho Silva, Guilherme Figueiredo Murari, Charles Elliot Serpellone Nash, Fabíola Z. Mónica, Edson Antunes, Gilberto De Nucci,

Aortic Disease and Treatment Approaches

Human umbilical cord vessels (HUCV) release dopamine and nitric oxide (NO). This study aims to verify whether HUCV release nitrocatecholamines such as 6-nitrodopamine (6-ND). Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to identify 6-ND release from HUCV rings incubated in Krebs-Henseileit's solution. Vascular reactivity of HUCV rings was tested (with and without endothelium integrity) by suspension of the rings in an organ bath under isometric tension and application of 6-ND and other known mediators. LC-MS/MS revealed a basal release of 6-ND from endothelium intact from both human umbilical artery (HUA) and vein (HUV). The endothelium intact release was inhibited by the pre-treatment with NO synthesis inhibitor L-NAME (100 μM). In contrast to dopamine, noradrenaline and adrenaline, 6-ND did not contract HUCV, even in presence of L-NAME or ODQ. 6-ND (10 μM) produced a rightward shift of the concentration-response curves to dopamine (pA2: 5.96 in HUA and 5.72 in HUV). Contractions induced by noradrenaline and adrenaline were not affected by pre-incubation with 6-ND (10 μM). In U-46619 (10 nM) pre-contracted endothelium intact tissues, 6-ND and the dopamine D2-receptor antagonist haloperidol induced concentration-dependent relaxations of HUA and HUV. Incubation with the dopamine D1-receptor antagonist SCH-23390 (10 nM) abolished relaxation induced by fenoldopam but did not affect those induced by 6-ND. 6-ND is released by HUCV and acts as a selective dopamine D2-receptor antagonist in this tissue. This represents a novel mechanism by which NO may modulate vascular reactivity independently of cGMP production.