ACTIVATION OF MITOGEN-ACTIVATED PROTEIN-KINASES (P38-MAPKS, SAPKS JNKS AND ERKS) BY ADENOSINE IN THE PERFUSED RAT-HEART/

Adenosine and mitogen-activated protein kinases (MAPKs) have been sepa rately implicated in cardiac ischaemic preconditioning. We investigate d the activation of MAPK subfamilies by adenosine in perfused rat hear ts. p38-MAPK was rapidly phosphorylated and activated (10-fold activat ion, maximal at 5 min) by 10 mM adenosine, as was the p38-MAPK substra te, MAPKAPK2 (4.5-fold). SAPKs/JNKs were activated (5-fold) and ERKs w ere phosphorylated (both maximal at 5 min), The concentration dependen ces of activation of p38-MAPK and ERKs were biphasic with a 'high affi nity' component (maximal at 10-100 mu M adenosine) and a 'low affinity ' component that had not saturated at 10 mM, SAPKs/JNKs were activated only by 10 mM adenosine, These results are consistent with MAPK invol vement in adenosine-mediated ischaemic preconditioning. (C) 1998 Feder ation of European Biochemical Societies.