THE CONSERVATION OF MITOCHONDRIAL-FUNCTION BY ISCHEMIA - THE ISCHEMIAPARADOX

The aim of this study was to compare oxidative phosphorylation of rat heart mitochondria, isolated. (i) immediately after excision of the he art: (ii) after 60 min of low flow normoxic perfusion; (iii) after 60 min oi high flow normoxic perfusion, (iv) after 30 min of no-flow isch aemia and (v) after 30 min ischaemia followed by 20 min reperfusion. T he results, using a retrogradely perfused rat hart as a model. show th at mitochondrial oxidative phosphorylation after 30 min of no-flow isc haemia showed no difference from oxidative phosphorylation measured on mitochondria isolated directly after excision of the heart. However, alter 30 min no-flow ischaemia followed by 20 min of reperfusion oxida tive phosphorylation deteriorated in comparison with oxidative phospho rylation alter 30 min of ischaemia only. Furthermore. oxidative phosph orylation after 60 min of non-ischaemic high flow perfusion (thus high coronary flow). compared better with oxidative phosphorylation after ischaemia-reperfusion than with oxidative phosphorylation after ischae mia alone.