Role of cyclic nucleotide phosphodiesterases in ischemic preconditioning
Date
1998
Authors
Lochner A.
Genade S.
Tromp E.
Opie L.
Moolman J.
Thomas S.
Podzuweit T.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Several signal transduction pathways have been implicated in the mechanism of protection induced by ischemic preconditioning (PC). For example, stimulation of a variety of G-protein coupled receptors results in stimulation of protein kinase C (PKC) which has been suggested to act as common denominator in eliciting protection. PC also significantly attenuated cAMP accumulation during sustained ischemia, suggesting involvement of an anti-adrenergic mechanism. The aim of this study was to evaluate the β-adrenergic signal transduction pathway (as evidenced by changes in tissue cAMP and cAMP- and cGMP-phosphodiesterase) during the PC protocol as well as during sustained ischemia. Isolated perfused rat hearts were preconditioned by 3 x 5 min global ischemia (PC1,2,3) interspersed by 5 min reperfusion, followed by 25 min global ischemia. Tissue cAMP- and cGMP-PDE activity as well as cAMP and cGMP levels were determined at different time intervals during the PC protocol and sustained ischemia. Tissue cAMP increased with each PC ischemic event and normalized upon reperfusion, while PDE activity showed the opposite, viz a reduction during ischemia and an increase during reperfusion. Except for PC1, tissue cGMP showed similar fluctuations. Throughout 25 min sustained ischemia, cAMP- and cGMP-PDE activities were higher in PC than in nonpreconditioned hearts, associated with a significantly lesser accumulation in cAMP and higher cGMP levels in the former. Fluctuations in cyclic nucleotides during preconditioning were associated with concomitant changes in PDE acitivity, while the attenuated β-adrenergic reponse of preconditioned hearts during sustained ischemia may partially be due to increased PDE activity.
Description
Keywords
cyclic amp, cyclic gmp, cyclic nucleotide phosphodiesterase, guanine nucleotide binding protein, phosphodiesterase, protein kinase c, adrenergic system, animal tissue, article, controlled study, enzyme activity, heart infarction prevention, heart muscle reperfusion, heart protection, isolated heart, nonhuman, rat, signal transduction, 3',5'-Cyclic-GMP Phosphodiesterase, 3',5'-Cyclic-Nucleotide Phosphodiesterase, Animals, Cyclic AMP, Cyclic GMP, Ischemic Preconditioning, Myocardial, Myocardial Ischemia, Myocardium, Rats, Rats, Wistar, Receptors, Adrenergic, beta, Signal Transduction, Time Factors
Citation
Molecular and Cellular Biochemistry
186
02-Jan
186
02-Jan