Perfusion of hearts with DETA/NO prevents ischemia-induced release of cytochrome c from mitochondria. (A) – mitochondrial cytochrome c, (B) – cytosolic cytochrome c. Content of cytochrome c in isolated mitochondria was measured spectrophotometrically from the characteristic spectra as described in Methods and was expressed as nmol/mg of mitochondrial protein. Cytosolic cytochrome c content was measured using ELISA kit and was expressed in ng/μg of cytosolic protein. * – Statistically significant effect of ischemia if compared to control (p < 0.01, Tukey test); # – statistically significant effect of DETA/NO if compared to ischemia (p < 0.01, Tukey test); ^ – statistically significant effect of KT 5823 (p < 0.05, LSD test) or ODQ (p < 0.01, Tukey test) if compared to ischemia + DETA/NO group. Means ± standard errors of 4–9 separate experiments are presented.