Adventitial Hydrogen Peroxide (H2O2) Impairs Rat Carotid Artery Relaxation via Medial p38 MAPK
Bibliographic record
Abstract
The vascular adventitia is a major source of H2O2. H2O2 activates smooth muscle p38 mitogen activated protein kinase (p38 MAPK). We postulated that adventitia‐derived H2O2 impairs relaxation via medial kinase activation. Isolated rat carotid arteries were bathed perivascularly (in situ) over 90 min in vehicle, angiotensin II (AngII, 500 nM), AngII + H2O2‐scavenger catalase or AngII + p38 MAPK inhibitor, then placed in myographs and preconstricted. Both acetylcholine (ACh)‐induced endothelium‐dependent and sodium nitroprusside (SNP)‐induced endothelium‐independent relaxations were impaired by AngII (p < 0.05). Catalase partially reversed the AngII effect on ACh‐induced relaxation and reversed impairment of SNP‐induced relaxations (p < 0.05). The p38 MAPK inhibitor SB203580 partially ameliorated the impairment of SNP‐induced relaxations and reversed the AngII effect on ACh‐induced relaxation (p < 0.05). In separate pretreated vessels, the media was dissected, homogenized and Western blots run for phosphorylated vs. total p38 MAPK. AngII activated medial p38 MAPK, but catalase inhibited this. These data suggest AngII elicits release of adventitial H2O2, impairing both endothelium‐dependent and –independent relaxation via the p38 MAPK pathway in the media. The data provide evidence of a significant paracrine signaling role of vascular adventitial H2O2 on vascular function.
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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) | 0.001 | 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".