“…When the reperfusion injury salvage kinase (RISK) family members PKA, PKB/Akt, PKC, and MEK-ERK are activated by pre-or post-conditioning, a common downstream protein, GSK-3b, is phosphorylated at Ser9, resulting in GSK-3b inhibition (both events occurring within 20 min of the end of conditioning), leading to the inhibition of mPTPs and the salvaging of 20-50% live myocardium. 4,5,[13][14][15][16] A potent GSK-3 inhibitor, SB216763 (SB21), 4,13 had a relatively weak protective effect against H 2 O 2 -, ONOO À -induced myocyte death (Supplementary Figure S2c), but gave better protection against 10 mM Zn 2 þ -induced cell toxicity at 4 h (Figure 2d (TUNEL test) were performed as follows: after ischemia for 40 min, followed by reperfusion for 4 h, myocytes were returned to normal medium without inhibitors for 24 h, then were examined for apoptotic markers. Compared with I/R alone ('I/R', Figure 4b), the presence of 15 mM TPEN at the start of reperfusion for only B20 min ('TPEN (20 min)') markedly inhibited I/R injury at 24 h after TPEN removal, suggesting that the reperfusion-induced initial Zn 2 þ i release (Figure 3b) is important in I/R injury.…”