Nitric oxide synthase inhibition reduces O<sub>2</sub> cost of force development and spares high‐energy phosphates following contractions in pump‐perfused rat hindlimb muscles
Bibliographic record
Abstract
The purpose of the present experiments was to test the hypotheses that: (i) nitric oxide synthase (NOS) inhibition reduces the O2 cost of force development across a range of contractile demands; and (ii) this reduced O2 cost of force development would be reflected in a sparing of intramuscular higher energy phosphates. Rat distal hindlimb muscles were pump perfused in situ and electrically stimulated (200 ms trains with pulses at 100 Hz, each pulse 0.05 ms duration) for 1 min each at 15, 30 and 60 tetani min(-1) and for 2 min at 90 tetani min(-1) in three groups: 0.01 mM adenosine; 1 mM D-NAME and 0.01 mM adenosine (D-NAME); and 1 mM L-NAME and 0.01 mM adenosine (L-NAME). The gastrocnemius-plantaris-soleus muscle group was freeze clamped post-contractions for metabolite analyses. Force was 19% higher and oxygen uptake (VO2) was 20% lower with L-NAME versus adenosine, and there was a 35% reduction in VO2/time-integrated tension versus adenosine and 24% versus D-NAME that was independent of contraction frequency. L-NAME treatment produced a 33% sparing of muscle phosphocreatine (PCr), and intramuscular lactate was no different between groups. In contrast, D-NAME reduced force by 30%, VO2 by 29% and the O2 cost of force development by 15% compared with adenosine, but had no effect on the degree of intramuscular ATP and PCr depletion. These results show that NOS inhibition improved the metabolic efficiency of force development, either by improving the ATP yield for a given O2 consumption or by reducing the ATP cost of force development. In addition, these effects were independent of contraction frequency.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".