Facilitation of noradrenaline release by activation of adenosine A(2A) receptors triggers both phospholipase C and adenylate cyclase pathways in rat tail artery

• Tipo: Artigo em Revista Científica Internacional
• Data: 2004

Autores

Fresco, P (Autor) FFUP; Diniz, C (Autor) FFUP; Goncalves, J (Autor) FFUP

Revista

Título: Cardiovascular Research

Vol. 63

Páginas: 739-746

ISSN: 0008-6363

Editora: Oxford University Press

Indexação

ISI Web of Knowledge - 23 Citações

Scopus - 35 Citações

Classificação Científica

FOS: Ciências médicas e da saúde > Medicina clínica

Outras Informações

ID Authenticus: P-000-8N2

DOI: 10.1016/j.cardiores.2004.05.015

Abstract (EN): Objective: The present work is aimed at elucidating the signalling pathway(s) triggered by activation of A(2A) receptors involved in the facilitation of noradrenaline release in rat tail artery as an attempt to clarify their role in the cardiovascular system. Methods: Electrically evoked (5 Hz, 100 pulses, 1 ms) tritium overflow was evaluated in preparations of rat tail artery, pre-incubated with [H-3]-noradrenaline (0.1 muM), in the absence or in the presence of adenosine receptor agonists and antagonists and/or activators and inhibitors of phospholipase C (PLC)-protein kinase C (PKC) and of adenylate cyclase (AC)-cyclic adenosine-3',5'-monophosphate (cAMP)-protein kinase A (PKA) pathways. Results: Activation of A(2A) receptors by 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680; 100 nM) enhanced tritium overflow, an effect prevented by the A2A receptor antagonist 5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo-[4,3]-1,2,4-triazolo[1,5]pyrimidine (SCH 58261; 20 nM), by the protein kinase A (PKA) inhibitor N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide (H-89; 1 muM), or the PKC inhibitor 2-(8-[(dimethylamino)methyl-6,7,8,9-tetrahydropyrido[1,2]indol-3-yl]-3-(1-methylindol-3-yl)maleimide (Ro 32-0432; 1 muM). The PKC activator phorbol 12-myristate 13-acetate (PMA; 1 muM) and the PKA activator 8-bromo-cAMP (0.5 mM) also enhanced tritium overflow. The effect caused by PMA was blunted both by Ro 32-0432 and by H-89 whereas that caused by 8-bromo-cAMP was only prevented by H-89. Conclusions: In rat tail artery, the A(2A) receptor-mediated facilitation of noradrenaline release requires activation of both PKC and PKA, and PKA activation seems to occur downstream of PKC activation.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8