Endothelin‐1‐endothelin receptor type A mediates closure of rat ductus arteriosus at birth
Bibliographic record
Abstract
1. The ductus arteriosus (DA) undergoes rapid closure after birth as pulmonary circulation is established. The involvement of endothelin-1 (ET1) in this closure mechanism is controversial. 2. The effect of ATZ1993 (ATZ), a non-peptide antagonist for the ET(A) and ET(B) receptors, on postnatal closure and O2-induced contraction of the rat DA was investigated both in vivo and in vitro. Rat pups were delivered by Caesarean section and were given ATZ intraperitoneally. The minimum external DA diameter and the extent of DA constriction in vivo were evaluated at 2.5 h after birth. ATZ caused a dose-dependent inhibition of DA closure in vivo. When rat pups were given ATZ at 2.5 h after birth, re-opening of the DA was observed. 3. In vitro, ATZ also caused a marked inhibition of O2-induced and ET1-induced DA contractions as did BQ123, an ET(A)-specific antagonist. In contrast, sarafotoxin S6c, an ET(B)-specific agonist, did not cause DA contraction and BQ788, an ET(B)-specific antagonist, did not affect O2-induced DA contraction. 4. In conclusion, ET1 and its cognate receptor ET(A) may play a physiological role in the postnatal closure of the rat DA in vivo.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".