Appetite-suppressing effects of ammonia exposure in rainbow trout associated with regional and temporal activation of brain monoaminergic and CRF systems
Bibliographic record
Abstract
To assess whether the brain's monoaminergic and/or corticotropin-releasing factor (CRF) systems may be involved in mediating the appetite-suppressing effects of high environmental ammonia levels, we exposed rainbow trout to one of four NH4Cl treatments (0, 500, 750, 1000 micromol l(-1)) for 24 or 96 h and monitored changes in food intake, brain serotonin (5-HT) and dopamine (DA) activity, CRF and urotensin I (UI) mRNA levels, and plasma cortisol levels. Food intake decreased in a dose-dependent manner after 24 h of ammonia exposure and partially recovered in all groups after 96 h. Ammonia also elicited dose-dependent increases in serotonergic activity in the hypothalamus (HYP), telencephalon (TEL) and posterior brain (PB). Whereas the increase in serotonergic activity was timed with the 24 h food intake inhibition, TEL and PB serotonergic activity increased after 96 h. In the PB, exogenous ammonia also elicited dose-dependent increases in dopaminergic activity after both 24 and 96 h of exposure. Transient increases in TEL CRF and UI mRNA levels, HYP UI mRNA levels, and plasma cortisol concentrations were evidence that the hypothalamic-pituitary-interrenal (HPI) stress axis was primarily stimulated in the first 24 h of ammonia exposure when food intake was depressed. Overall, the transient nature of the appetite suppression during chronic ammonia exposure, and the time-dependent changes in brain monoaminergic and CRF systems, implicate 5-HT, DA, CRF and UI as potential mediators of the appetite-suppressing effects of ammonia. Among these anorexigenic signals, our results specifically identify hypothalamic 5-HT as a potentially key neurobiological substrate for the regulation of food intake during exposure to high external ammonia concentrations.
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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 | 0.000 |
| 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".