Journal
INTERNATIONAL JOURNAL OF BIOCHEMISTRY & CELL BIOLOGY
Volume 34, Issue 4, Pages 348-357Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S1357-2725(01)00138-8
Keywords
melatonin; mitochondria; ATP; electron chain transport; complex I; complex IV; oxidative stress
Categories
Ask authors/readers for more resources
We recently showed that melatonin counteracted mitochondrial oxidative stress and increased the activity of the mitochondrial oxidative phosphorylation (OXPHOS) enzymes both in vivo and in vitro. To further clarify these effects, we studied here the activity of OXPHOS enzymes and the synthesis of ATP in rat liver and brain mitochondria in vitro. In sub-mitochondrial particles, melatonin increases the activity of the complexes I and IV dose-dependently, the effect being significant between I and 10 nM. Blue native-PAGE followed by histochemical analysis of the OXPHOS enzymes further showed the melatonin-induced increase of complex I activity. Titration studies show that melatonin counteracts the partial inhibition of complex IV induced by 5 muM potassium cyanide. However, melatonin (up to 5 mM) was unable to recover the activity of complex IV when it was completely blocked by 100 muM cyanide. These data suggest that the indoleamine could stimulate the activity of the non-inhibited part of the complex IV. Melatonin also increases the production of ATP in control mitochondria and counteracts the cyanide-induced inhibition of ATP synthesis. These results provide new hormonal mechanism regulating mitochondrial homeostasis and may explain, at least in part, the anti-aging and neuroprotective properties of melatonin. (C) 2002 Elsevier Science Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available