Effects of hyperthermia and acidosis on mitochondrial oxidative phosphorylation

• DOI: 10.1152/japplphysiol.00418.2024
• Publication Date: 2024-11-27T16:01:26Z
• Authors: Michael S. Davis; Warwick M. Bayly; Cristina M. Hansen; Montana R. Barrett; Cara A. Blake
• Keywords: Lactic acidosis; Cellular respiration

The intracellular environment of skeletal muscle can develop pronounced hyperthermia and acidosis during strenuous exercise, these alterations in the typical conditions have been shown to alter mitochondrial respiration. However, impact on ATP synthesis is poorly understood. We used Thoroughbred racehorses test hypothesis that both decrease rate synthesis, but athletic conditioning mitigates this loss phosphorylation capacity. Isolated mitochondria were harvested from before after a 9-week racetrack program increased whole-body aerobic capacity by 19%, oxidative was tested ex vivo under normothermic hyperthermic conditions, as well normal pH acidic created addition lactic acid. In unfit horses, caused 30-55% efficiency (P/O ratio decreased 4.2 1.7 maximal phosphorylation). Aerobic resulted conditions. Lactic had small negative effect sensitivity isolated deleterious effects acidosis. These data support prominent role fatigue particularly subjects. may be more important cause failure fit