EFFECT OF CONTRACTILE ACTIVITY ON SUBSARCOLEMMAL AND INTERMYOFIBRILLAR MITOCHONDRIAL RESPIRATION AND NF-KB DNA BINDING
Bibliographic record
Abstract
Skeletal muscle contains two morphologically distinct subfractions of mitochondria which are found in separate locations in the cell. Subsarcolemmal (SS) mitochondria are located beneath the surface of the sarcolemma and intermyofibrillar (IMF) mitochondria are found intermingled within the myofibrils. SS and IMF subfractions possess different enzyme activities and respiratory rates, and they adapt differently to contractile activity. The purpose of this study was to determine if there is a differential adaptive response of IMF and SS mitochondrial respiration to chronic stimulation (1,2,3,5,7 days, 10Hz, 3hrs/d, n = 2–7/day) of rat tibialis anterior muscles. Since oxygen consumption is associated with the production of reactive oxygen species (ROS), and these are known activators of the transcription factor NF-kB, we also measured NF-kB-DNA binding using electromobility shift assays (n = 4/day). Following 1 day of stimulation, SS mitochondrial state 3 and 4 respiration rates were transiently decreased by 40–50% in stimulated, compared to control muscle. This was followed by a return to control levels of state 4 respiration, and a dramatic 63% increase in state 3 respiration above control levels between 3–5d of stimulation. SS mitochondrial state 3 respiration returned to control levels by 7d. In contrast, IMF mitochondrial state 3 and 4 respiration rates were not changed between 1–5d, but increased in parallel by 35–40% after 7d of stimulation. Electromobility shift assays revealed elevated levels of NF-kB binding above that in control muscle extracts by 40% after 1d, 130% after 5d, and 80% after 7d (n = 4) of stimulation. These data indicate chronic contractile activity induces early increases in NF-kB binding which precede changes in muscle respiratory capacity. In addition, contractile activity induces differential adaptive responses with respect to IMF and SS mitochondrial respiration rates.
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".