Acute and chronic contractile activity-induced adaptations in muscle and mitochondrial function
Bibliographic record
Abstract
Exercise training is a potent stimulus for favourable phenotypic adaptations in muscle, including the induction of mitochondrial biogenesis. Although the occurrence of organelle expansion in response to chronic muscle use is accepted, the cellular events governing this remodeling are undefined. Thus, the purpose of this dissertation was to examine the acute and chronic contractile activity-induced adaptations in skeletal muscle and mitochondrial function in young and old animals. The intracellular signals associated with contractile activity are important for the induction of downstream phenotypic plasticity. In study 1, we investigated the influence of muscle oxygen consumption and reactive oxygen species (ROS) production on kinase signaling. The results demonstrate that mitochondrial content influenced the rate of ROS production in resting muscle. Furthermore, several protein kinases were differentially sensitive to increments in oxygen consumption, and this sensitivity was also related to the muscle mitochondrial volume. In study 2, we further explored the effect of mitochondrial content on the acute contraction-induced kinase signaling in skeletal muscle. We found that mitochondrial content was inversely related to kinase activation in resting skeletal muscle. Moreover, training-induced increases in mitochondrial volume were associated with an attenuated adaptive signaling response subsequent to a single bout of contractions, suggesting a mitochondrially mediated mechanism regulating training-elicited muscle remodeling. The aim of study 3 was to examine the effect of age on the acute exercise-induced signaling response. Skeletal muscle from old animals exhibited pathophysiological properties, including reduced force production, fatigue resistance, mitochondrial content, and ATP-synthesizing ability, all characteristic of aging-associated sarcopenia. This condition was correlated with an attenuated signaling response to acute exercise, which was dependent on muscle mitochondrial content. Study 4 assessed the adaptive plasticity of mitochondria in young and old animals after chronic muscle use. We found that the mitochondria from aged animals were able to adapt favourably to a period of chronic contractile activity, despite an attenuated signaling response after each individual bout of exercise. However, the adaptive plasticity of aged animals was lower than that observed in young animals. These findings underscore the importance of daily physical activity in the maintenance and improvement of health for individuals of all ages.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".