Functional characteristics of alpha adrenoceptors in isolated pressurized rat mesenteric small veins
Bibliographic record
Abstract
Vasomotor tone is largely maintained by norepinephrine (NE) released by sympathetic nerves and activating mainly alpha adrenergic receptors (α‐ARs). We investigated the relative contributions of α‐ARs to NE contractile responses in rat mesenteric vessels. Pressure myography was used to study isolated third order mesenteric small veins (6 or 12 mmHg) and arteries (60 or 120 mmHg). NE and phenylephrine (PE) concentration response curves (CRC) were constructed at normal and high transmural pressures in the absence and presence of α‐AR antagonists. Clonidine CRC were obtained at normal transmural pressures. All agonists evoked concentration dependent contractions with NE and PE being more potent in veins compared with arteries. In veins, NE was a more potent agonist than PE. Phentolamine (α‐AR antagonist, 10 μM) and prazosin (α1‐AR antagonist, 100 nM) completely abolished NE responses in all vessels. Yohimbine (α2‐AR antagonist, 100 nM) significantly reduced NE CRC in veins at 6 mmHg. Clonidine responses in veins were significantly reduced by yohimbine. These results indicate the predominant involvement of α1‐ARs in NE‐induced contractions of pressurized mesenteric vessels with no change in the contribution of α1‐ARs as pressure increased. In addition to α1‐ARs, α2‐ARs mediate NE responses in veins at 6 mmHg. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada.
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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 | 0.000 |
| 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".