Investigation on the positive chronotropic action of 6-nitrodopamine in the rat isolated atria
José Britto Júnior, Antonio Tiago Lima, Vivian Fuguhara, Fabiola Z. Monica, Edson Antunes, Gilberto de Nucci
ARTIGO
Inglês
Agradecimentos: JBJ thanks FAPESP for the post-doctoral fellowship (2021/14414-8). ATL and VF thank FAPESP for PhD fellowship (2021/13593-6, 2022/07737-8). EA and FM thank FAPESP (2017/15175-1). GDN thanks FAPESP (2019/16805-4) and CNPq (303839/2019-8)
Abstract: 6-Nitrodopamine (6-ND) is released from rat isolated atria being 100 times more potent than noradrenaline and adrenaline, and 10,000 times more potent than dopamine as a positive chronotropic agent. The present study aimed to investigate the interactions of 6-ND with the classical...
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Abstract: 6-Nitrodopamine (6-ND) is released from rat isolated atria being 100 times more potent than noradrenaline and adrenaline, and 10,000 times more potent than dopamine as a positive chronotropic agent. The present study aimed to investigate the interactions of 6-ND with the classical catecholamines, phosphodiesterase (PDE)-3 and PDE4, and the protein kinase A in rat isolated atria. Atrial incubation with 1 pM of dopamine, noradrenaline, or adrenaline had no effect on atrial frequency. Similar results were observed when the atria were incubated with 0.01 pM of 6-ND. However, co-incubation of 6-ND (0.01 pM) with dopamine, noradrenaline, or adrenaline (1 pM each) resulted in significant increases in atrial rate, which persisted over 30 min after washout of the agonists. The increased atrial frequency induced by co-incubation of 6-ND with the catecholamines was significantly reduced by the voltage-gated sodium channel blocker tetrodotoxin (1 µM, 30 min), indicating that the positive chronotropic effect of 6-ND is due in part to activation of nerve terminals. Pre-treatment of the animals with reserpine had no effect on the positive chronotropic effect induced by dopamine, noradrenaline, or adrenaline; however, reserpine markedly reduced the 6-ND (1 pM)-induced positive chronotropic effect. Incubation of the rat isolated atria with the protein kinase A inhibitor H-89 (1 µM, 30 min) abolished the increased atrial frequency induced by dopamine, noradrenaline, and adrenaline, but only attenuated the increases induced by 6-ND. 6-ND induces catecholamine release from adrenergic terminals and increases atrial frequency independently of PKA activation
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FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP
2017/15175-1; 2019/16805-4; 2021/14414-8; 2021/13593-6; 2022/07737-8
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ
303839/2019-8
Fechado
Lima, Vivian Fuguhara de
Autor
Antunes, Edson, 1960-
Autor
Investigation on the positive chronotropic action of 6-nitrodopamine in the rat isolated atria
José Britto Júnior, Antonio Tiago Lima, Vivian Fuguhara, Fabiola Z. Monica, Edson Antunes, Gilberto de Nucci
Investigation on the positive chronotropic action of 6-nitrodopamine in the rat isolated atria
José Britto Júnior, Antonio Tiago Lima, Vivian Fuguhara, Fabiola Z. Monica, Edson Antunes, Gilberto de Nucci
Fontes
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Naunyn-Schmiedeberg's archives of pharmacology v. 396, p. 1279-1290, 2023 |