The negative chronotropic effects of (±)-propranolol and (±)-4-NO2-propranolol in the rat isolated right atrium are due to blockade of the 6-nitrodopamine receptor

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MetadadosDescriçãoIdioma
Autor(es): dc.contributorUniversidade Estadual de Campinas (UNICAMP)-
Autor(es): dc.contributorUniversity of Naples Federico II-
Autor(es): dc.contributorUniversidade Estadual Paulista (UNESP)-
Autor(es): dc.contributorUniversidade de São Paulo (USP)-
Autor(es): dc.creatorOliveira, Denis Lima-
Autor(es): dc.creatorCardoso, Vinicius Francisco-
Autor(es): dc.creatorBritto-Júnior, Jose-
Autor(es): dc.creatorFuguhara, Vivian-
Autor(es): dc.creatorFrecentese, Francesco-
Autor(es): dc.creatorSparaco, Rosa-
Autor(es): dc.creatorSantagada, Vincenzo-
Autor(es): dc.creatorCaliendo, Giuseppe-
Autor(es): dc.creatorPupo, André Sampaio-
Autor(es): dc.creatorAntunes, Edson-
Autor(es): dc.creatorDe Nucci, Gilberto-
Data de aceite: dc.date.accessioned2025-08-21T21:25:45Z-
Data de disponibilização: dc.date.available2025-08-21T21:25:45Z-
Data de envio: dc.date.issued2025-04-29-
Data de envio: dc.date.issued2023-12-31-
Fonte completa do material: dc.identifierhttp://dx.doi.org/10.1007/s00210-024-03463-3-
Fonte completa do material: dc.identifierhttps://hdl.handle.net/11449/308656-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/11449/308656-
Descrição: dc.descriptionThe positive chronotropic action induced by 6-nitrodopamine (6-ND) is selectively blocked by β1-adrenoceptor antagonists at concentrations that do not affect the positive chronotropic effect induced by dopamine, noradrenaline, and adrenaline. Here, the effects of (±)-propranolol, (±)-4-NO2-propranolol, and (±)-7-NO2-propranolol were investigated in the rat isolated right atrium. The atrium was mounted in glass chambers containing gassed (95%O2:5%CO2) and warmed (37 °C) Krebs–Henseleit’s solution, and the isometric tension registered (PowerLab system). (±)-Propranolol, (±)-4-NO2-propranolol, and (±)-7-NO2-propranolol caused concentration-dependent falls in the spontaneous atrial frequency (pIC50: 4.80 ± 0.10, 4.64 ± 0.10, and 4.95 ± 0.10, respectively). The calculated pA2 values for (±)-propranolol, (±)-4-NO2-propranolol, and (±)-7-NO2-propranol on noradrenaline-induced positive chronotropism were 8.44 ± 0.08, 6.41 ± 0.07, and 9.21 ± 0.29, respectively. The positive chronotropism induced by 6-ND (10 pM) was blocked by (±)-propranolol (1 µM) and (±)-4-NO2-propranolol (30 nM), whereas (±)-7-NO2-propranolol (1 µM) had no effect on 6-ND-induced responses. The pIC50 of (±)-propranolol, (±)-4-NO2-propranolol, and (±)-7-NO2-propranolol were significantly shifted to the right in L-NAME-treated atria. The discrepancy between pA2 values of (±)-propranolol and its respective pIC50 indicates that the falls in atrial rate induced by (±)-propranolol should not be attributed to b-adrenergic antagonism. The reduced chronotropism by (±)-propranolol was unaffected by the sodium channel inhibitors tetrodotoxin and lidocaine but that was abolished in atria pre-treated with (±)-4-NO2-propranolol. The finding that (±)-propranolol reduces spontaneous atrial rate only in concentrations that affect 6-ND-induced positive chronotropism confirms the role of this catecholamine as an endogenous modulator of heart chronotropism. (±)-4-NO2-Propranolol behaves as a selective antagonist of 6-ND in the rat isolated atrium.-
Descrição: dc.descriptionDepartment of Pharmacology Faculty of Medical Sciences State University of Campinas (UNICAMP), 126 Tessália Vieira de Camargo St, São Paulo-
Descrição: dc.descriptionDepartment of Pharmacy School of Medicine University of Naples Federico II-
Descrição: dc.descriptionDepartment of Biophysics and Pharmacology Institute of Biosciences São Paulo State University (UNESP)-
Descrição: dc.descriptionDepartment of Pharmacology Institute of Biomedical Sciences University of São Paulo (ICB-USP)-
Descrição: dc.descriptionDepartment of Biophysics and Pharmacology Institute of Biosciences São Paulo State University (UNESP)-
Idioma: dc.languageen-
Relação: dc.relationNaunyn-Schmiedeberg's Archives of Pharmacology-
???dc.source???: dc.sourceScopus-
Palavras-chave: dc.subjectBeta-blocker-
Palavras-chave: dc.subjectCatecholamines-
Palavras-chave: dc.subjectL-NAME-
Palavras-chave: dc.subjectStereoselectivity-
Título: dc.titleThe negative chronotropic effects of (±)-propranolol and (±)-4-NO2-propranolol in the rat isolated right atrium are due to blockade of the 6-nitrodopamine receptor-
Tipo de arquivo: dc.typelivro digital-
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