Table 1.

Effects of DETA-NO on oxygen consumption using different inhibitors and substrates

Treatment	Pathways	Oxygen consumption (% of controls) at time of analysis after administration of DETA-NO
		20 min	20 min + Hb	3 h	3 h + Hb	6 h	6 h + Hb
None		19.4  ± 0.81	100  ± 1.11	13.7  ± 0.73	32.5  ± 0.87	13.3  ± 0.56	13.4  ± 0.76
Pyruvate	Citric acid cycle/ complexes I-III-IV	18.0  ± 0.98	102  ± 1.12	15.4  ± 0.67	36.4  ± 0.13	14.6  ± 0.06	14.3  ± 0.71
3-Nitropropionic acid +
β-hydroxybutyrate	Complexes I-III-IV	20.6  ± 1.22	101  ± 2.76	13.5  ± 0.67	36.3  ± 0.25	13.1  ± 0.78	13.2  ± 0.21
Myxothiazol +
TMPD/ascorbate	Complex IV	21.3  ± 1.34	104  ± 0.89	15.3  ± 1.26	105  ± 0.97	14.1  ± 0.84	106  ± 1.02
Rotenone + succinate	Complexes II-III-IV	19.7  ± 0.67	108  ± 1.22	13.2  ± 0.27	103  ± 1.43	13.5  ± 1.65	107  ± 1.12

Cells were resuspended in the incubation medium and then treated with various blockers of the mitochondrial respiratory complexes in the presence of specific substrates as indicated. DETA-NO (0.5 mM) was then added and oxygen consumption was analyzed before and after addition of Hb (8 μM) at the indicated time point. Values are expressed as percentage of that in cells treated with the same inhibitors and substrates but incubated in the absence of DETA-NO. The concentrations of the various inhibitors of the mitochondrial respiratory chain, as well as of the appropriate substrates, were selected in preliminary experiments as described in Materials and Methods. n = 4.