Branchial expression and localization of SLC9A2 and SLC9A3 sodium/hydrogen exchangers and their possible role in acid–base regulation in freshwater rainbow trout (<i>Oncorhynchus mykiss</i>)
Bibliographic record
Abstract
Experiments were conducted on adult rainbow trout (Oncorhynchus mykiss) to test the hypothesis that SLC9 Na+/H+ exchangers (SLC9A2, NHE2; and SLC9A3, NHE3) on the gill epithelium are localized specifically to a subset of mitochondria-rich cells (MRCs) that are unable to bind peanut lectin agglutinin (PNA). This cell type, termed the PNA- MRC, is a sub-type of MRC believed to function in Na+ uptake and acid excretion. A technique using biotinylated PNA was used to distinguish between the PNA- and PNA+ MRCs on fixed gill sections. In contrast to expectations, both NHE2 (mRNA) and NHE3 (protein) were confined to cells enriched with Na+/K+-ATPase and capable of binding PNA. Thus, in trout, NHE2 and NHE3 are localized to PNA+ MRCs, the cells previously believed to be responsible for Cl- uptake and base excretion. Levels of mRNA for NHE2, the predominant isoform in the gill, were increased during 72 h of hypercapnic acidosis; NHE3 mRNA and protein levels were unaffected. Because plasma cortisol levels were increased during hypercapnia (from 35.3+/-9.4 to 100.1+/-30.9 ng ml(-1)), the effects of experimentally elevated cortisol levels on NHE expression were investigated. The elevation of plasma cortisol using intraperitoneal implants caused a significant increase in NHE2 mRNA expression without affecting NHE3 mRNA or protein abundance. Thus, we suggest that NHE2 contributes to acid-base regulation during hypercapnia owing to its transcriptional regulation by cortisol. The finding of NHE expression in PNA+ MRCs is discussed with reference to current models of ionic and acid-base regulation in teleost fish.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".