Relaxant Effect of Chemotactic Peptides on Rabbit Vascular Strips: Evidence for Nitric Oxide Release from a Nonendothelial Source
Bibliographic record
Abstract
Two distinct peptides, C5a and f-Met-Leu-Phe (FMLP), that are chemotactic for phagocytic leukocytes affect profoundly the circulation in various in vivo systems. These peptides are known to relax strips of rabbit isolated blood vessels, the portal vein and pulmonary artery. In the present study, the effect of recombinant human C5a (2.5-25 nM) was examined and found to be qualitatively similar to that previously reported for FMLP. Indomethacin completely or partially inhibited the vasorelaxations induced by either peptide in the pulmonary artery and the portal vein, respectively. The relaxation induced by C5a was not abolished by removing the endothelial lining of the model vessels. The C5a or FMLP effects were more tachyphylactic in tissues continuously exposed to cycloheximide; this phenomenon was particularly pronounced for FMLP. A series of experiments were focused on the indomethacin-resistant component of the relaxation induced by either peptide on the portal vein. This component was not inhibited by capsaicin pretreatment or by endothelium removal, but was suppressed by treatment with NG-nitro-L-arginine or reduced by LY-83583. These findings suggest that the chemotactic peptides elicit their mechanical effect on rabbit vascular smooth muscle through the release of secondary mediators not related to the endothelium; the mediators are tentatively identified as prostaglandins and nitric oxide. It is the coordinated combinations of the metabolic pathways that are involved in the final responses, with inherent differences between vessel sources and the agonists used.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".