Picard 2008 Am J Physiol Regul Integr Comp Physiol: Difference between revisions
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|journal=Am J Physiol Regul Integr Comp Physiol | |journal=Am J Physiol Regul Integr Comp Physiol | ||
|abstract=This study determined whether susceptibility to opening of the permeability transition pore (PTP) varies according to muscle phenotype represented by the slow oxidative soleus (Sol) and superficial white gastrocnemius (WG). Threshold for | |abstract=This study determined whether susceptibility to opening of the permeability transition pore (PTP) varies according to muscle phenotype represented by the slow oxidative soleus (Sol) and superficial white gastrocnemius (WG). Threshold for Ca<sup>2+</sup>-induced mitochondrial Ca<sup>2+</sup> release following PTP opening was determined with a novel approach using permeabilized ghost myofibers. Threshold values for PTP opening were approximately threefold higher in fibers from WG compared with those from Sol (124ยฑ47 vs. 30.4ยฑ6.8 pmol Ca<sup>2+</sup>/mU citrate synthase). A similar phenomenon was also observed in isolated mitochondria (threshold: 121ยฑ60 vs. 40ยฑ10 nmol Ca<sup>2+</sup>/mg protein in WG and Sol), indicating that this was linked to differences in mitochondrial factors between the two muscles. The resistance of WG fibers to PTP opening was not related to the expression of putative protein modulators (cyclophilin D, adenylate nucleotide translocator-1, and voltage-dependent anion channels) or to difference in respiratory properties and occurred despite the fact that production of reactive oxygen species, which promote pore opening, was higher than in the Sol. However, endogenous matrix Ca<sup>2+</sup> measured in mitochondria isolated under resting baseline conditions was approximately twofold lower in the WG than in the Sol (56ยฑ4 vs. 111ยฑ11 nmol/mg protein), which significantly accounted for the resistance of WG. Together, these results reveal fiber type differences in the sensitivity to Ca<sup>2+</sup>-induced PTP opening, which may constitute a physiological mechanism to adapt mitochondria to the differences in Ca<sup>2+</sup> dynamics between fiber types. | ||
|editor=Gnaiger E | |editor=Gnaiger E | ||
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Revision as of 12:04, 18 December 2022
Picard M, Csukly K, Robillard ME, Godin R, Ascah A, Bourcier-Lucas C, Burelle Y (2008) Resistance to Ca2+-induced opening of the permeability transition pore differs in mitochondria from glycolytic and oxidative muscles. Am J Physiol Regul Integr Comp Physiol 295:R659-68. doi: 10.1152/ajpregu.90357.2008 |
Picard M, Csukly K, Robillard ME, Godin R, Ascah A, Bourcier-Lucas C, Burelle Y (2008) Am J Physiol Regul Integr Comp Physiol
Abstract: This study determined whether susceptibility to opening of the permeability transition pore (PTP) varies according to muscle phenotype represented by the slow oxidative soleus (Sol) and superficial white gastrocnemius (WG). Threshold for Ca2+-induced mitochondrial Ca2+ release following PTP opening was determined with a novel approach using permeabilized ghost myofibers. Threshold values for PTP opening were approximately threefold higher in fibers from WG compared with those from Sol (124ยฑ47 vs. 30.4ยฑ6.8 pmol Ca2+/mU citrate synthase). A similar phenomenon was also observed in isolated mitochondria (threshold: 121ยฑ60 vs. 40ยฑ10 nmol Ca2+/mg protein in WG and Sol), indicating that this was linked to differences in mitochondrial factors between the two muscles. The resistance of WG fibers to PTP opening was not related to the expression of putative protein modulators (cyclophilin D, adenylate nucleotide translocator-1, and voltage-dependent anion channels) or to difference in respiratory properties and occurred despite the fact that production of reactive oxygen species, which promote pore opening, was higher than in the Sol. However, endogenous matrix Ca2+ measured in mitochondria isolated under resting baseline conditions was approximately twofold lower in the WG than in the Sol (56ยฑ4 vs. 111ยฑ11 nmol/mg protein), which significantly accounted for the resistance of WG. Together, these results reveal fiber type differences in the sensitivity to Ca2+-induced PTP opening, which may constitute a physiological mechanism to adapt mitochondria to the differences in Ca2+ dynamics between fiber types.
โข Bioblast editor: Gnaiger E
Labels:
Stress:Permeability transition Organism: Rat Tissue;cell: Skeletal muscle
Regulation: Calcium