Application of modular kinetic analysis to mitochondrial oxidative phosphorylation in skeletal muscle of birds exposed to acute heat stress.
We previously showed that heat stress stimulates reactive oxygen species (ROS) production in skeletal muscle mitochondria of birds, probably via an elevation in mitochondrial membrane potential (DeltaPsi). To clarify the mechanism underlying the elevation of DeltaPsi, modular kinetic analysis was applied to oxidative phosphorylation in skeletal muscle mitochondria of heat-stressed birds (34 degrees C for 12h). In the birds exposed to heat stress, 'substrate oxidation' (a DeltaPsi-producer) was increased compared to control (24 degrees C) birds, although there was little difference in 'proton leak' (a DeltaPsi-consumer), suggesting that an elevation in the DeltaPsi at state 4 may be due to enhanced substrate oxidation. It thus appears that enhanced substrate oxidation plays a crucial role in the overproduction of ROS for heat-stressed birds, probably via elevated DeltaPsi.
Division of Life Science, Graduate School of Agricultural Science, Tohoku University, Aoba-ku, Sendai, Japan.
Motoi
M
Kikusato
Jon J
JJ
Ramsey
Taku
T
Amo
Masaaki
M
Toyomizu
D000818:Animals; D001717:Birds / Q000378:metabolism; D018882:Heat Stress Disorders / Q000378:metabolism*; D006358:Hot Temperature; D007700:Kinetics; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010085:Oxidative Phosphorylation; D011522:Protons; D017382:Reactive Oxygen Species / Q000378:metabolism
D011522:Protons; D017382:Reactive Oxygen Species