Specific activation of adenylyl cyclase V by a purinergic agonist.
The present study was designed to investigate whether and how the purinergic stimulation of rat ventricular myocytes modulates the cAMP-dependent pathway. Stimulation of cardiomyocytes with ATPgammaS in the presence of the phosphodiesterase inhibitor IBMX increases by 3-fold intracellular cAMP content. In contrast to beta-adrenergic stimulation, the purinergic stimulation of adenylyl cyclase was not inhibited by activation or enhanced by inhibition of a Gi protein. Forskolin did not potentiate the effect of extracellular ATPgammaS on intracellular cAMP content but the effect of isoproterenol did. Like isoproterenol, the purinergic agonist decreased subsequent ADP-ribosylation of a 45 kDa G(alpha s) by cholera toxin. ATPgammaS also increased cAMP content in neonatal rat cardiomyocytes, a cell type that expresses a long form of Gs protein (alpha(s), 52 kDa) in contrast to adult rat cardiomyocytes that express mostly a short form of Gs protein (alpha(s), 45 kDa). Both purinergic and beta-adrenergic agonists increased cAMP in HEK 293 cells expressing type V adenylyl cyclase while cAMP was only increased by beta-adrenergic stimulation of HEK expressing type IV or VI adenylyl cyclases. Thus, we propose that the purinergic and beta-adrenergic stimulations differentially activate adenylyl cyclase isoforms in rat cardiomyocytes and that adenylyl cyclase V is the specific target of the purinergic stimulation.
INSERM U-390, Laboratoire de Physiopathologie Cardiovasculaire, C.H.U. Arnaud de Villeneuve, Montpellier, France. puceat@u390.montp.inserm.fr
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D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D003497:Cyclic N-Oxides / Q000494:pharmacology*; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D058910:Purinergic P2 Receptor Agonists; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000378:metabolism
D000318:Adrenergic beta-Agonists; D003497:Cyclic N-Oxides; D058910:Purinergic P2 Receptor Agonists; D018048:Receptors, Purinergic P2; C096873:adenosine 5'-O-(S-acetamidoproxyl 3-thiotriphosphate); D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D007545:Isoproterenol