Differential effects of AMP-activated protein kinase in isolated rat atria subjected to simulated ischemia-reperfusion depending on the energetic substrates available.

AMP-activated protein kinase (AMPK) is a serine-threonine kinase that functions primarily as a metabolic sensor to coordinate anabolic and catabolic processes in the cell, via phosphorylation of multiple proteins involved in metabolic pathways, aimed to re-establish energy homeostasis at a cell-autonomous level. Myocardial ischemia and reperfusion represents a metabolic stress situation for myocytes. Whether AMPK plays a critical role in the metabolic and functional responses involved in these conditions remains uncertain.

Effects of wortmannin on cardioprotection exerted by ischemic preconditioning in rat hearts subjected to ischemia-reperfusion.

Ischemic preconditioning (IPC) is one of the most powerful interventions to reduce ischemia-reperfusion injury. The aim of the present study was to investigate the involvement of the phosphatidylinositol-3-kinases (PI3Ks) family in cardioprotection exerted by IPC and the relationship between preservation of mitochondrial morphology and ATP synthesis capacity. In this regard, macroautophagy (autophagy) is considered a dynamic process involved in the replacement of aged or defective organelles under physiological conditions.

Effects of 3-methyladenine on isolated left atria subjected to simulated ischaemia-reperfusion.

Although autophagy is a prominent feature of myocardial ischaemia and reperfusion, its functional significance is unclear and controversial. In order to gain a deeper insight into the role of autophagy in myocardial ischaemia-reperfusion, we explored the effects of the pharmacological inhibitor of autophagy 3-methyladenine (3-MA). Isolated rat atria subjected to simulated 75-min ischaemia/75-min reperfusion (Is-Rs) in the presence or absence of 3-MA were used.