Systemic and renal haemodynamic responses to the selective AT1 receptor antagonist ZD 7155 and the selective AT2 receptor antagonist PD 123319 during postnatal maturation in conscious lambs
Bibliographic record
Abstract
This study was designed to investigate the role of endogenously produced angiotensin II (ANG II) in modulating systemic and renal hemodynamics during postnatal maturation as well as the receptors through which it exerts these effects. Experiments were carried out in conscious, chronically instrumented lambs aged ~one‐week (age 8±2 days, n=14) and ~six weeks (age 41±3 days, n=23). At least four days after surgery under halothane anesthesia for placement of vessel catheters and a flow transducer around the left renal artery (Transonics System Inc.), mean arterial pressure (MAP), mean venous pressure (MVP) and renal blood flow (RBF) were measured for 10 min before (Control) and for 120 min after I.V. injection of one of the following doses of ZD 7155 (0, 100, 200, 400, 800, 1600 μg·kg −1 ), or PD 123319 (0, 100, 200, 400). A maximum of 3 experiments was carried out in each animal in random order and at minimum intervals of 48 h. RVR was calculated from the measured variables. There was a dose‐dependent decrease in MAP by 30 min after ZD 7155, the duration of which was also dose‐dependent. MAP responses to ZD 7155 were similar at one and six weeks of age. At all doses of ZD 7155 tested, RVR decreased by 5 min leading to an increase in RBF; control RVR and RBF were reached by 60 min. These renal haemodynamic responses to ZD 7155 were neither age‐ nor dose‐dependent. There were no significant effects of PD 123319 or vehicle on the measured or calculated variables. These data provide evidence that ANG II modulates cardiovascular homeostasis and renal vascular tone early in life through 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".