Angiotensin II–Induced Ca<sup>2+</sup>Influx in Renal Afferent and Efferent Arterioles
Bibliographic record
Abstract
Angiotensin II (Ang II)-induced Ca(2+) signaling was studied in isolated rat renal arterioles using fura-2. Ang II (10 nmol/L) caused a sustained elevation in [Ca(2+)](i), which was dependent on [Ca(2+)](o) in both vessel types. This response was blocked by nifedipine in only the afferent arteriole. Using the Mn(2+) quench technique, we found that Ang II stimulates Ca(2+) influx in both vessels. Nifedipine blocked the Ang II-induced Ca(2+) influx in afferent arterioles but not in efferent arterioles. In contrast to Ang II, KCl-induced depolarization stimulated Ca(2+) influx in only the afferent arteriole. Cyclopiazonic acid (CPA, 30 micromol/L) was used to examine the presence of store-operated Ca(2+) entry in myocytes isolated from each arteriole. In efferent myocytes, CPA induced a sustained Ca(2+) increase that was dependent on [Ca(2+)](o) and insensitive to nifedipine. This mechanism was absent in afferent myocytes. SKF 96365 inhibited Ang II-induced Ca(2+) entry in efferent arterioles and CPA-induced Ca(2+) entry in efferent myocytes over identical concentrations. Our findings thus indicate that Ang II activates differing Ca(2+) influx mechanisms in pre- and postglomerular arterioles. In the afferent arteriole, Ang II activates dihydropyridine-sensitive L-type Ca(2+) channels, presumably by membrane depolarization. In the efferent arteriole, Ang II appears to stimulate Ca(2+) entry via store-operated Ca(2+) influx.
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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 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".