Dose‐dependent systemic and renal haemodynamic effects of angiotensin II in conscious lambs: role of angiotensin AT<sub>1</sub> and AT<sub>2</sub> receptors
Bibliographic record
Abstract
The present experiments were designed to measure the effects of acute administration of angiotensin (ANG) II on mean arterial pressure (MAP) and renal blood flow (RBF) in conscious, chronically instrumented lambs at two different stages of postnatal maturation, and to determine the receptors through which these effects of ANG II are elicited. Experiments consisted of haemodynamic measurements for 10 s before (Control) and for 60 s after intravenous (i.v.) administration of one of 11 doses of ANG II (0-200 ng kg(-1)). Administration of ANG II was associated with a dose-dependent increase in MAP to a maximal effective concentration (EC100) of 100 ng kg(-1) in lambs aged 1 and 6 weeks. Administration of ANG II has caused a dose-dependent decrease in RBF, with EC100 values of 50 ng kg(-1) in 1-week-old lambs, and 25 ng kg(-1) in 6-week-old lambs. Responses to ANG II at the EC(50) were also measured in the presence of the specific ANG II AT(1) receptor antagonist, ZD 7155, the specific AT2 receptor antagonist, PD 123319, and vehicle. Administration of ZD 7155, but not PD 123319 or vehicle, abolished the MAP and RBF responses to ANG II in both age groups. In addition, MAP decreased and RBF increased in both age groups after administration of ZD 7155, but not PD 123319; the effects were similar in both age groups. These data provide new information that pressor and renal vasoconstrictor effects of ANG II during the first 6 weeks of postnatal life in lambs are elicited by activation of AT1 but not AT2 receptors.
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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 | 0.001 |
| 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".