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

• Type: Article in International Scientific Journal
• Date: 2004

Authors

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

Journal

Title: Cardiovascular Research

Vol. 63

Pages: 739-746

ISSN: 0008-6363

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 23 Citations

Scopus - 35 Citations

Scientific classification

FOS: Medical and Health sciences > Clinical medicine

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8