Experimental design.

Control group (CTRL) cardiomyocytes were superfused/reperfused with Tyrode standard solution for 25 min. Ischemic/reperfused group (I/R): superfusion with Tyrode standard for 5 min, ischemic buffer (IB) for 15 min, and Tyrode standard (reperfusion) for 5 min. Ischemic + Cst group (Cst): superfusion with Tyrode standard + 5 nM Cst for 5 min, IB + 5 nM Cst for 15 min, and Tyrode standard alone for 5 min (reperfusion). Wortmannin (Cst + Wm), L-NMMA (Cst + L-NMMA) and ODQ (Cst + ODQ) groups: cardiomyocytes were treated as Cst group, in the presence of 100 nM Wm, 1 mM L-NMMA or 100 μM ODQ together with 5 nM Cst.