pH recovery from a proton load in rat cardiomyocytes: effects of chronic exercise
Bibliographic record
Abstract
The ability of cardiomyocytes to recover from a proton load was examined in the hearts of exercise-trained and sedentary control rats in CO 2 /[Formula: see text]-free media. Acidosis was created by the NH 4 Cl prepulse technique, and intracellular pH (pH i ) was determined using fluorescence microscopy on carboxy-SNARF-1 AM-loaded isolated cardiomyocytes. CO 2 -independent pH i buffering capacity (β i ) was measured by incrementally reducing the extracellular NH 4 Cl concentration in steps of 50% from 20 to 1.25 mM. β i increased as pH i decreased in both exercise-trained and sedentary control groups. However, the magnitude of increase in β i as a function of pH i was found to be significantly ( P < 0.001) greater in the exercise-trained group compared with the sedentary control group. The rate of pH i recovery from an imposed proton load was found to not be different between the exercise-trained and control groups. The Na + /H + exchanger-dependent H + extrusion rate during the recovery from an imposed proton load, however, was found to be significantly greater in the exercise-trained group compared with the control group. By increasing β i and subsequently the Na + /H + exchanger-dependent H + extrusion rate, exercise training may provide cardiomyocytes with the ability to better handle an intracellular excess of H + generated during hypoxia/ischemic insults and may serve in a cardioprotective role. These data may be predictive of two positive outcomes: 1) increased exercise tolerance by the heart and 2) a protective mechanism that limits the degree of myocardial acidosis and subsequent damage that accompanies ischemia-reperfusion stress. NEW & NOTEWORTHY The enhanced ability to deal with acidosis conferred by exercise training is likely to improve exercise tolerance and outcomes in response to myocardial ischemia-reperfusion injury.
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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) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".