Role of Oxidative Stress in Ischemia–Reperfusion-Induced Changes in Na <sup>+</sup> ,K <sup>+</sup> -ATPase Isoform Expression in Rat Heart
Bibliographic record
Abstract
The aim of this study was to assess whether depression of cardiac Na+,K(+)-ATPase activity during ischemia/reperfusion (I/R) is associated with alterations in Na+,K(+)-ATPase isoforms, and if oxidative stress participates in these I/R-induced changes. Na+,K(+)-ATPase alpha1, alpha2, alpha3, beta1, beta2, and beta3 isoform contents were measured in isolated rat hearts subjected to I/R (30 min of global ischemia followed by 60 min of reperfusion) in the presence or absence of superoxide dismutase plus catalase (SOD+CAT). Effects of oxidative stress on Na+,K(+)-ATPase isoforms were also examined by perfusing the hearts for 20 min with 300 microM hydrogen peroxide or 2 mM xanthine plus 0.03 U/ml xanthine oxidase (XXO). I/R significantly reduced the protein levels of all alpha and beta isoforms. Treatment of I/R hearts with SOD+CAT preserved the levels of alpha2, alpha3, beta1, beta2, and beta3 isoforms, but not that of the alpha1 isoform. Perfusion of hearts with hydrogen peroxide and XXO depressed all Na+,K(+)-ATPase alpha and beta isoforms, except for alpha1. These results indicate that the I/R-induced decrease in Na+,K(+)-ATPase may be due to changes in Na+,K(+)-ATPase isoform expression and that oxidative stress plays a role in this alteration. Antioxidant treatment attenuated the I/R-induced changes in expression of all isoforms except alpha1, which appears to be more resistant to oxidative stress.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".