Tretter 2012 Free Radic Biol Med: Difference between revisions
No edit summary |
Bader Helga (talk | contribs) No edit summary |
||
Line 13: | Line 13: | ||
|organism=Guinea pig | |organism=Guinea pig | ||
|tissues=Nervous system | |tissues=Nervous system | ||
|preparations=Isolated | |preparations=Isolated mitochondria | ||
|injuries=RONS | |injuries=Oxidative stress;RONS | ||
|substratestates=GpDH | |substratestates=GpDH | ||
|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
|additional=Fura-6F; Amplex Red; Safranin | |additional=Fura-6F; Amplex Red; Safranin | ||
}} | }} |
Revision as of 14:40, 13 February 2015
Tretter L, Adam-Vizi V (2012) High Ca2+ load promotes hydrogen peroxide generation via activation of ฮฑ-glycerophosphate dehydrogenase in brain mitochondria. Free Radic Biol Med 53:2119-30. |
Tretter L, Adam-Vizi V (2012) Free Radic Biol Med
Abstract: H2O2 generation associated with ฮฑ-glycerophosphate (ฮฑ-GP) oxidation was addressed in guinea pig brain mitochondria challenged with high Ca2+ load (10 ฮผM). Exposure to 10 ฮผM Ca2+ induced an abrupt 2.5-fold increase in H2O2 release compared to that measured in the presence of a physiological cytosolic Ca2+ concentration (100 nM) from mitochondria respiring on 5 mM ฮฑ-GP in the presence of ADP (2 mM). The Ca2+-induced stimulation of H2O2 generation was reversible and unaltered by the uniporter blocker Ru 360, indicating that it did not require Ca2+ uptake into mitochondria. Enhanced H2O2 generation by Ca2+ was also observed in the absence of ADP when mitochondria exhibited permeability transition pore opening with a decrease in the NAD(P)H level, dissipation of membrane potential, and mitochondrial swelling. Furthermore, mitochondria treated with the pore-forming peptide alamethicin also responded with an elevated H2O2 generation to a challenge with 10 ฮผM Ca2+. Ca2+-induced promotion of H2O2 formation was further enhanced by the Complex III inhibitor myxothiazol. With 20 mM ฮฑ-GP concentration, stimulation of H2O2 formation by Ca2+ was detected only in the presence, not in the absence, of ADP. It is concluded that ฮฑ-glycerophosphate dehydrogenase, which is accessible to and could be activated by a rise in the level of cytosolic Ca2+, makes a major contribution to Ca2+-stimulated H2O2 generation. This work highlights a unique high-Ca2+-stimulated reactive oxygen species-forming mechanism in association with oxidation of ฮฑ-GP, which is largely independent of the bioenergetic state and can proceed even in damaged, functionally incompetent mitochondria. โข Keywords: Mitochondria; Reactive oxygen species; Calcium; Hydrogen peroxide; ฮฑ-Glycerophosphate dehydrogenase; Reverse electron transport; Permeability transition pore; Myxothiazol; ฮฑ-Glycerophosphate shuttle; Free radicals
โข O2k-Network Lab: HU_Budapest_Tretter L
Labels: MiParea: Respiration
Stress:Oxidative stress;RONS Organism: Guinea pig Tissue;cell: Nervous system Preparation: Isolated mitochondria
HRR: Oxygraph-2k
Fura-6F; Amplex Red; Safranin