CASP3 and ischemia: By analysing the caspase-3 substrate PARP, which is cleaved in a consequence of apoptotic cascade activation, we could distinguish an increase of cleaved-PARP in ischemic HL-1 cardiomyocytes eight hours after ischemia induction (5-fold) indicating that apoptosis plays a crucial role in ischemia, although revitalization leads to a decrease of cleaved-PARP in ischemic HL-1 cardiomyocytes.