Extracellular hyper‐osmolality increases resting skeletal muscle lactate in mammalian skeletal muscle
Bibliographic record
Abstract
The current study investigated the affects of acute alterations in extracellular osmolality on resting in‐vitro skeletal muscle. Isolated, whole muscle strips (Soleus and EDL) from 5 week old Long Evans rats were incubated for 60 min in an organ bath containing Sigma Medium‐199 (resting tension (1g), bubbled with 95:5 O 2 :CO 2 , 30 ± 2°C, and pH 7.4). Three different osmotic states were used; an iso‐osmotic (290±10 Osm) (CON), hyper‐osmotic (400 ±10 Osm) (HYPR), and hypo‐osmotic (190 ± 10 Osm) (HYPO). After incubation, the relative water content decreased with HYPR, and increased with HYPO in both muscle types. As a result of the HYPO type I fiber area was increased in the Soleus (HYPO = 4066.3 ± 634.4μm 2 , CON = 2990 ± 364.1 μm 2 , n=12, p<0.05), whereas only TYPE II fiber area was increased in the EDL (HYPO = 2419.3 ± 681.5 μm 2 , CON = 1729.1 ± 513.1μm 2 , n>11, p<0.001). HYPR resulted in increased muscle lactate concentrations (EDL, p<0.001; Soleus, p<0.001, n=51) in both muscle types, but no extracellular lactate content was detected. Glycogen content decreased in EDL as a result of HYPR (HYPR=79.3 ± 11.8 mmol/kg, ISO=94.3.3 ± 16.1, p<0.01), whereas glycogen content in the soleus increased in HYPO (HYPO= 92.5 ± 12.2 mmol/kg, ISO=76.6 ± 18.5 mmol/kg, p<0.05). ATP and PCr concentrations confirmed muscle viability. Therefore, acute exposure of skeletal muscle to extracellular osmolality increases intracellular concentrations of lactate. The specific mechanisms underlying these changes in lactate remain to be determined. Supported by NSERC, Canada.
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".