1. Basal release and relaxation responses to 6-nitrodopamine in swine carotid, coronary, femoral, and renal arteries.
- Author
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Campos R, Niederauer AJS, Britto-Júnior J, de Souza VB, Schenka AA, Monica FZ, Moraes MO, Moraes MEA, Antunes E, and De Nucci G
- Subjects
- Animals, Male, Swine, Femoral Artery drug effects, Femoral Artery metabolism, Femoral Artery physiology, Coronary Vessels drug effects, Coronary Vessels physiology, Coronary Vessels metabolism, Renal Artery drug effects, Renal Artery metabolism, Renal Artery physiology, Dopamine metabolism, Carotid Arteries drug effects, Carotid Arteries metabolism, Carotid Arteries physiology, Endothelium, Vascular drug effects, Endothelium, Vascular metabolism, Endothelium, Vascular physiology, Vasodilator Agents pharmacology, Vasodilation drug effects
- Abstract
Mammalian and reptilian vascular tissues present basal release of 6-nitrodopamine, which is reduced when the tissues are pre-incubated with the NO synthase inhibitor L-N
G -Nitro arginine methyl ester (L-NAME), or when the endothelium is mechanically removed. 6-Nitrodopamine induces vasorelaxation in pre-contracted vascular rings by antagonizing the dopaminergic D2-like receptor. Here it was investigated whether male swine vessels (including carotid, left descendent coronary, renal, and femoral arteries) release 6-nitrodopamine, dopamine, noradrenaline, and adrenaline, as measured by liquid chromatography coupled to tandem mass spectrometry. The in vitro vasorelaxant action of 6-nitrodopamine was evaluated in carotid, coronary, renal, and femoral arteries precontracted by U-46619 (3 nM), and compared to that induced by the dopamine D2 -receptor antagonist L-741,626. Expression of tyrosine hydroxylase and the neuromaker calretinin was investigated by immunohistochemistry. All vascular tissues presented basal release of endothelium-derived catecholamines. The relaxation induced by 6-nitrodopamine was not affected by preincubation of the tissues with either L-NAME (100 μM, 30-min preincubation) or the heme-site inhibitor of soluble guanylyl cyclase ODQ (100 μM, 30-min preincubation). Electrical field stimulation (EFS)-induced contractions were significantly potentiated by previous incubation with L-NAME, but unaffected by ODQ preincubation. The contractions induced by EFS were reduced by preincubation with either 6-nitrodopamine or L-741,626. Immunohistochemistry in all arteries revealed the presence of tyrosine hydroxylase in the endothelium, whereas immunoreactivity for calretinin was negative. Swine vessels present basal release of endothelium-derived catecholamines and expression of tyrosine hydroxylase in the endothelium. The vasodilation induced by 6-nitrodopamine is due to blockade of dopaminergic D2 -like receptors., Competing Interests: Declaration of competing interest The authors declare no competing or financial interests., (Copyright © 2024. Published by Elsevier Inc.)- Published
- 2024
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