[Genipin--uncoupling protein inhibitor--reduces the protective effect of ischemic preconditioning]

The functional significance of uncoupling proteins UCP2 and UCP3 in the cell and the organism remains unknown. There have been reports about their involvement in cellular protection mechanisms underlying the phenomenon of ischemic preconditioning. The purpose of this study was to elucidate the role of uncoupling proteins UCP2 and UCP3 in the formation of cardioprotective effect of ischemic preconditioning. In experiments on isolated rat hearts we show here an increase in the level of UCP2 and UCP3 gene expression in the heart tissue under the influence of ischemic preconditioning with three episodes of 5 min stopping the flow perfusion. Similar effects were induced by a prolonged ischemia-reperfusion of myocardium. The blockade of the UCP2 activity by genipin (Wako Inc., USA, 10(-5) mol/L, isolated heart perfusion for 15 minutes) abolished the protective effect of adaptation to ischemia. It was concluded that uncoupling proteins take part in the cardioprotective effect ofischemic preconditioning.