Effective protection by NHE-1 inhibition in ischemic and reperfused heart under preconditioning blockade.

We compared the protective effects of ischemic preconditioning (IPC) and the Na(+)/H(+) exchanger-1 (NHE-1) inhibitor cariporide in isolated rat hearts subjected to global ischemia (45 or 90 min) and 30-min reperfusion and determined the protective effects of cariporide under IPC blockade with the mitochondrial ATP-sensitive K(+) channel blocker 5-hydroxydecanoate (5-HD). With 45-min ischemia, both IPC and cariporide equally increased maximum recovery of left ventricular developed pressure twofold (P < 0.05), although recovery was significantly greater with cariporide for the first 15 min of reperfusion.