Coronary β-Adrenoceptor Function Is Modified by the Endothelium in Heart Failure
Bibliographic record
Abstract
Congestive heart failure is associated with abnormalities in myocardial beta-adrenoceptor function. The extent of vascular beta-adrenoceptor alterations at heart failure, however, is unknown. Accordingly, we examined beta-adrenoceptor-mediated relaxations in both circumflex (CRX) and left anterior descending (LAD) coronary arteries with and without endothelium from dogs in early and end-stage heart failure induced by rapid ventricular pacing (1 and 4 weeks pacing at 250 beats x min-1, respectively). At early heart failure, (1) CRX with endothelium were more sensitive to isoproterenol than CRX without endothelium (EC50: 1.1 x 10(-8) vs. 1.6 x 10(-7) M, p<0.05); and (2) in response to salbutamol, CRX with endothelium had a lower maximum relaxation response than CRX without endothelium (56.6 vs. 75.9%, p<0.05). At end-stage heart failure, (1) endothelium-intact CRX and LAD showed a significant decrease in sensitivity to isoproterenol compared to control (CRX-EC50: end-stage heart failure: 1.1 x 10(-7) vs. control: 1.8 x 10(-8)M,p<0.05; and LAD-EC50: end-stage heart failure: 8.8 x 10(-7) M vs. control: 8.3 x 10(-8) M, p<0.05); (2) LAD with endothelium showed greater maximum relaxation to salbutamol than LAD without endothelium (100.8 vs. 76.5%, p<0.05); and (3) CRX were significantly more sensitive to isoproterenol than LAD. These data suggest that coronary vascular tone via beta-adrenoceptor stimulation is coronary artery-dependent, and modulated not only by the heart failure state, but also by the presence of a functional endothelium.
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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 | 0.001 |
| 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".