The FGF-2-triggered protection of cardiac subsarcolemmal mitochondria from calcium overload is mitochondrial connexin 43-dependent.

Aims: Fibroblast growth factor 2 (FGF-2) protects the heart from ischaemia- and reperfusion-induced cell death by a mechanism linked to protein kinase C (PKC)ε-mediated connexin 43 (Cx43) phosphorylation. Cx43 localizes predominantly to gap junctions, but has also been detected at subsarcolemmal (SSM), but not interfibrillar (IFM), mitochondria, where it is considered important for cardioprotection. We have now examined the effect of FGF-2 administration to the heart on resistance to calcium-induced permeability transition (mPTP) of isolated SSM vs.

Mitochondrial oxidative phosphorylation in hearts subjected to Ca2+ depletion and Ca2+ repletion.

Repletion of Ca2+ in the Ca2+-depleted heart has been shown to produce cardiac dysfunction, myocardial cell damage, intracellular Ca2+ overload, and defects in sarcolemmal and sarcoplasmic reticulum function (Ca2+ paradox). Although these alterations in the Ca2+-paradox heart are associated with a depression in the high-energy phosphate stores, little information regarding changes in mitochondrial oxidative phosphorylation is available. Perfusion of rat hearts with Ca2+-free medium for 5 min followed by reperfusion with a medium containing 1.

Role of oxidative stress in alterations of mitochondrial function in ischemic-reperfused hearts.

To study the mechanisms of mitochondrial dysfunction due to ischemia-reperfusion (I/R) injury, rat hearts were subjected to 20 or 30 min of global ischemia followed by 30 min of reperfusion. After recording both left ventricular developed pressure (LVDP) and end-diastolic pressure (LVEDP) to monitor the status of cardiac performance, mitochondria from these hearts were isolated to determine respiratory and oxidative phosphorylation activities. Although hearts subjected to 20 min of ischemia failed to generate LVDP and showed a marked increase in LVEDP, no changes in mitochondrial respiration and phosphorylation were observed.