Ultrastructural modifications and phosphatidylinositol-3-kinase expression and activity in myocardial tissue deriving from rats in different experimental conditions

Oxygen supply is essential in the maintenance of the physiological cell metabolism. In fact, both lower and higher Oz concentrations induce modifications of the enzymatic activity of the cell which determine, in turn, morphological changes at nuclear and cytoplasmic level. Among the molecules involved in the maintenance of the cellular homeostasis, the signal transduction pathway PI-3-kinase/AKT-1 should be included. Here we suggest a relationship between the modulation of this pathway and the morphological modifications occurring "in vivo" in myocardial tissue upon hypoxic and hyperoxic stress. In particular, down regulation of this pathway, which when activated is known to deliver an anti-apoptotic signal, is concomitant to the maintenance of the apoptotic events occurring in these cells in response to oxidative stresses.