The Influence of Calcium Channel Antagonists on Isolated Human Distal Radial Arteries
Bibliographic record
Abstract
A comparison was made between the efficacies and potencies of calcium channel antagonists on contractions induced by 5-hydroxytryptamine, norepinephrine, or high-potassium buffer in isolated human distal radial arteries. Also, the impact of removal of extracellular calcium ions on contractions induced by 5-hydroxytryptamine or norepinephrine was assessed. Isometric contractions were induced by agonists, and relaxant responses to calcium channel antagonists, nifedipine, diltiazem, verapamil, or mibefradil were examined. 5-hydroxytryptamine-induced contractions when compared with norepinephrine or high-potassium induced contractions were significantly more sensitive to inhibition by nifedipine (pIC50 = 7.53 +/- 0.15; 6.78 +/- 0.12; 6.6 +/- 0.22, respectively, mean +/- SEM). Diltiazem was more effective in producing relaxations when contractions were elicited with 5-hydroxytryptamine (pIC50 = 6.48 +/- 0.84) or norepinephrine (pIC50 = 6.20 +/- 0.21) than with high potassium (pIC50 = 5.43 +/- 0.10). Verapamil was more effective at relaxing arteries contracted with 5-hydroxytryptamine (pIC50 = 6.09 +/- 0.19) or norepinephrine (pIC50 = 6.00 +/- 0.17) than with high potassium (pIC50 = 5.60 +/- 0.16). Mibefradil was not very effective in producing relaxations. The studies revealed that removal of extracellular calcium significantly attenuated contractions produced by 5-hydroxytryptamine (-67.7 +/- 6.3%) and norepinephrine (-89 +/- 1.5%). In conclusion, our data indicates that nifedipine was the most effective drug in producing relaxations; also, contractions produced by 5-hydroxytryptamine and norepinephrine were found to be critically dependent on the presence of extracellular calcium.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".