CYCS and ischemia: Borutaite et al9 proposed that mPTP opening might be responsible, but our data do not support this.8 Thus, the deoxyglucose entrapment technique did not detect mPTP opening in situ at the end of ischemia, and this is consistent with the inhibition of mPTP opening at the low pH values occurring in ischemia.10 Furthermore, unlike Borutaite et al, we were unable to prevent the release of cytochrome c when mPTP opening was inhibited with CsA.