Hedges 2018 FASEB J

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Hedges CP, Bishop DJ, Hickey AJR (2018) Voluntary wheel running prevents the acidosis-induced decrease in skeletal muscle mitochondrial reactive oxygen species emission. FASEB J [Epub ahead of print].

» PMID: 30596520

Hedges CP, Bishop DJ, Hickey AJR (2018) FASEB J

Abstract: Decreases in pH (acidosis) in vitro can alter skeletal muscle mitochondrial function [respiration and reactive oxygen species (ROS) emission]. However, because skeletal muscles readily adapt to exercise, the effects of acidosis may be different on sedentary vs. trained muscle. The aim of this work was to compare the effects of pH on skeletal muscle mitochondrial function between sedentary vs. exercise-trained male Sprague-Dawley rats ( n = 10 in each cohort). Rates of mitochondrial respiration and ROS emission were determined from the soleus muscle of both cohorts over a physiologic range of pH values (pH 6.2-7.1). Exercise-trained rats had 14% higher mean muscle buffering capacities; 46 and 40% greater enzyme activity of citrate synthase and lactate dehydrogenase, respectively; and greater activity of respiratory complexes I-IV. ADP-stimulated respiration with complex I and II substrates was ∼25% greater in exercise-trained rats but was unaffected by pH in either cohort. In both cohorts, lowering pH decreased respiration only in complex I- and complex II-supported nonphosphorylating (leak) state. However, as pH decreased, ROS emissions in complex I- and complex II-supported leak state decreased only in sedentary rats; in exercise-trained rats, ROS emissions in this state remained constant. We hypothesize that this effect may result from modulation at complex III, which declined 47% per unit pH in sedentary rats, in comparison to 23% in exercise-trained rats. Taken together, these data suggest that pH regulates mitochondrial respiratory complexes and that exercise training can decrease the effects of pH on skeletal muscle mitochondrial function.

Keywords: ROS, Mitochondria function, Oxidative phosphorylation, Oxidative stress, pH Bioblast editor: Plangger M O2k-Network Lab: NZ Auckland Hickey AJ, AU Melbourne Stepto NK


Labels: MiParea: Respiration, Exercise physiology;nutrition;life style 

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

Regulation: pH  Coupling state: LEAK, OXPHOS, ET  Pathway: N, NS, ROX  HRR: Oxygraph-2k, O2k-Fluorometer 

Labels, 2019-01, Amplex UltraRed