NOS3 and myocardial infarction: Compared with the ischemia-reperfusion model group, the group that received an intravenous injection of 10 mg/kg tanshinone IIA prior to reperfusion had a reduced myocardial infarct size, higher levels of phospho-Akt and phospho-endothelial nitric oxide synthase and less reduction in the optical density of the mitochondria at 540 nm, indicating that the mitochondrial permeability transition (MPT) was attenuated.