PRKG1 and ischemia: Selective PKG inhibitor KT5823 at 1 μM concentration applied together with DETA/NO before ischemia significantly decreased the ability of DETA/NO to prevent cytochrome c loss from mitochondria and its accumulation in cytosol: mitochondrial cytochrome c level was significantly reduced and cytosolic level significantly increased in DETA/NO plus KT5823 perfused ischemic hearts compared to DETA/NO perfused hearts (Fig. 3A and 3B).