Cookies help us deliver our services. By using our services, you agree to our use of cookies. More information

Anderson 2006 Am J Physiol Cell Physiol

From Bioblast
Revision as of 12:34, 18 December 2022 by Gnaiger Erich (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision β†’ (diff)
Publications in the MiPMap
Anderson EJ, Neufer PD (2006) Type II skeletal myofibers possess unique properties that potentiate mitochondrial H2O2 generation. Am J Physiol Cell Physiol 290:C844-51. doi: 10.1152/ajpcell.00402.2005

Β» PMID: 16251473 Open Access

Anderson EJ, Neufer PD (2006) Am J Physiol Cell Physiol

Abstract: Mitochondrial dysfunction is implicated in a number of skeletal muscle pathologies, most notably aging-induced atrophy and loss of type II myofibers. Although oxygen-derived free radicals are thought to be a primary cause of mitochondrial dysfunction, the underlying factors governing mitochondrial superoxide production in different skeletal myofiber types is unknown. Using a novel in situ approach to measure H2O2 production (indicator of superoxide formation) in permeabilized rat skeletal muscle fiber bundles, we found that mitochondrial free radical leak H2O2 produced/O2 consumed) is two- to threefold higher (p < 0.05) in white (WG, primarily type IIB fibers) than in red (RG, type IIA) gastrocnemius or soleus (type I) myofibers during basal respiration supported by Complex I (pyruvate + malate) or Complex II (succinate) substrates. In the presence of respiratory inhibitors, maximal rates of superoxide produced at both Complex I and Complex III are markedly higher in RG and WG than in soleus muscle despite approximately 50 % less mitochondrial content in WG myofibers. Duplicate experiments conducted with +/-exogenous superoxide dismutase revealed striking differences in the topology and/or dismutation of superoxide in WG vs. soleus and RG muscle. When normalized for mitochondrial content, overall H2O2 scavenging capacity is lower in RG and WG fibers, whereas glutathione peroxidase activity, which is largely responsible for H2O2 removal in mitochondria, is similar in all three muscle types. These findings suggest that type II myofibers, particularly type IIB, possess unique properties that potentiate mitochondrial superoxide production and/or release, providing a potential mechanism for the heterogeneous development of mitochondrial dysfunction in skeletal muscle.

β€’ Bioblast editor: Gnaiger E

Labels: MiParea: Respiration 

Stress:Oxidative stress;RONS  Organism: Rat  Tissue;cell: Skeletal muscle  Preparation: Permeabilized tissue