While
nitric oxide (NO) induces cardioprotection by targeting the
mitochondrial permeability transition pore (mPTP), the precise mitochondrial signaling events that mediate the action of NO remain unclear. The purpose of this study was to test whether NO induces cardioprotection against
ischemia/reperfusion by inhibiting oxidative stress through mitochondrial
zinc and
Src tyrosine kinase. The NO donor S-nitroso-N-acetyl
penicillamine (SNAP) given before the onset of
ischemia reduced cell death in rat cardiomyocytes subjected to simulated
ischemia/reperfusion, and this was abolished by the
zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (
TPEN) and the
Src tyrosine kinase inhibitor PP2. SNAP also prevented loss of mitochondrial membrane potential (ΔΨm) at reperfusion, an effect that was blocked by
TPEN and PP2. SNAP increased mitochondrion-free
zinc upon reperfusion and enhanced mitochondrial Src phosphorylation in a
zinc-dependent manner. SNAP inhibited both mitochondrial complex I activity and mitochondrial
reactive oxygen species (ROS) generation at reperfusion through
zinc and
Src tyrosine kinase. Finally, the anti-
infarct effect of SNAP was abrogated by
TPEN and PP2 applied at reperfusion in isolated rat hearts. In conclusion, NO induces cardioprotection at reperfusion by targeting mitochondria through attenuation of oxidative stress resulted from the inhibition of complex I at reperfusion. Activation of mitochondrial
Src tyrosine kinase by
zinc may account for the inhibition of complex I.