Studies on the angiotensin-converting enzyme and the kinin B<sub>2</sub>receptor in the rabbit jugular vein: modulation of contractile response to bradykinin
Bibliographic record
Abstract
The rabbit jugular vein (rbJV) was used as a bioassay system to validate some early and new hypothetical interactions between the angiotensin-converting enzyme (ACE) and the B2 receptor, which may be influenced by ACE inhibitors (ACE-I). These involve the potentiation of the contractile effect of bradykinin (BK) and BK analogues, which are inactivated by ACE (e.g., [Hyp3, Tyr(Me8)]-BK (R556)), the prevention of BK-induced B2 receptor desensitisation, and the restoration of receptor sensitivity in tissues desensitised with B2 receptor agonists. Enzymatic degradation studies performed in vitro and in vivo revealed that BK and R556 are readily degraded by rabbit ACE whereas [Phe8psi(CH2-NH)Arg9]-BK (R379) is totally resistant. BK, R556, and R379 contracted endothelium-denuded veins with similar potencies (pEC50 range 8.10-8.50). Tissues pretreated with ACE-I showed an increase in pEC50 values for BK and R556 but not for R379. ACE-I (captopril, enalaprilat) were unable to prevent B2 receptor desensitisation induced by BK (1 microM). ACE-I partially restored B2 receptor-mediated contraction in tissues initially exposed to BK but not to R379. These effects were antagonised by HOE 140 (0.1 microM) but were unaffected by AcLys[Dbeta-Nal7, Ile8]-desArg9BK (R715) (1 microM) or by Losartan (1 microM). In conclusion, the potentiation of BK and its analogues relates exclusively on prevention of their metabolism, B2 receptor desensitisation is not affected by ACE-I, and restoration of tissue responsiveness to BK by ACE-I may be attributed to changes in BK concentrations in the vicinity of the B2 receptor.
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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 | 0.001 | 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".