Multiple Mechanisms of Activating Ca <sup>2+</sup> Entry in Freshly Isolated Rabbit Aortic Endothelial Cells
Bibliographic record
Abstract
In Fura-2-loaded, freshly isolated rabbit aortic endothelial cells the Ca2+ entry pathway was investigated using the Mn2(+)-quenching technique. Acetylcholine (ACh) interaction with muscarinic receptors activated Mn2+ influx through the plasma membrane. Sarcoplasmic-endoplasmic reticulum Ca2+ ATPase blockers such as cyclopiazonic acid (CPA), thapsigargin and BHQ, which block the endoplasmic reticulum Ca2+ pump and do not interact with receptors, also activated Mn2+ influx. Mn2+ influx activated by either ACh or CPA was blocked by the following agents: SKF96365, a receptor-operated Ca2+ channel (ROC) blocker; NCDC, a PLC and ROC blocker, and genistein, a tyrosine kinase inhibitor. D600, the L-type Ca2+ channel blocker, had no significant effect on Mn2+ influx. Caffeine blocked the ACh-induced Ca2+ release but had no effect on the ACh-induced Mn2+ influx. Similarly dantrolene, which blocked intracellular Ca2+ release induced by ACh, did not affect the ACh-activated Mn2+ influx. These data suggest that ACh can activate Ca2+ influx without depletion of the ACh-sensitive intracellular Ca2+ store. It is concluded (1) that in freshly isolated endothelial cells depletion of the intracellular Ca2+ store is not necessary for ACh-activated Ca2+ influx, and (2) that receptor activation and intracellular Ca2+ store depletion may activate the same Ca2+ entry pathway through parallel mechanisms.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".