Hif‐1α is not required for the development of cardiac adrenergic control in zebrafish (<i>Danio rerio</i>)
Bibliographic record
Abstract
Abstract Adrenergic regulation, acting via the sympathetic nervous system, provides a major mechanism to control cardiac function. It has recently been shown that hypoxia inducible factor‐1α (Hif‐1α) is necessary for normal development of sympathetic innervation and control of cardiac function in the mouse. To investigate whether this may represent a fundamental trait shared across vertebrates, we assessed adrenergic regulation of the heart in wild‐type and Hif‐1α knockout (hif‐1α −/−) zebrafish (Danio rerio). Wild‐type and hif‐1α −/− zebrafish larvae (aged 4 and 7 days postfertilisation) exhibited similar routine heart rates within a given age group, and β‐adrenergic receptor blockade with propranolol universally reduced heart rate to comparable levels, indicating similar adrenergic tone in both genotypes. In adult fish, in vivo heart rate measured during anaesthesia was identical between genotypes. Treatment of spontaneously beating hearts in vitro with adrenaline revealed a similar positive chronotropic effect and similar maximum heart rates in both genotypes. Tyrosine hydroxylase immunohistochemistry with confocal microscopy demonstrated that the bulbus arteriosus (outflow tract of the teleost heart) of adult fish was particularly well innervated by sympathetic nerves, and nerve density (as a percentage of bulbus arteriosus area) was similar between wild‐types and hif‐1α −/− mutants. In summary, we did not find any evidence that adrenergic cardiac control was perturbed in larval or adult zebrafish lacking Hif‐1α. We conclude that Hif‐1α is not essential for the normal development of cardiovascular control or adult sympathetic cardiac innervation in zebrafish, although it is possible that it plays a redundant or auxiliary role.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".