Activity of the unique β-adrenergic Na<sup>+</sup>/H<sup>+</sup>exchanger in trout erythrocytes is controlled by a novel β<sub>3</sub>-AR subtype
Bibliographic record
Abstract
beta-Adrenoceptors (beta-ARs) are seven-transmembrane domain, G protein-coupled receptors that transduce the cellular effects of epinephrine and norepinephrine and play a pivotal role in the vertebrate stress response. This study reports the cloning and characterization of two previously unreported beta-ARs from the rainbow trout (Oncorhynchus mykiss). Phylogenetic analysis of amino acid sequences indicates that both beta-ARs are homologs of the mammalian beta3-AR. Analysis of tissue expression patterns indicates that one of these trout beta3-adrenoceptors (beta3a-AR) is highly expressed in gill and heart, whereas the second (beta3b-AR) is highly expressed by red blood cells (RBC). Expression of the beta3b-AR in the RBC coupled with the finding of a single category of beta-AR binding sites on RBC membranes provides strong evidence for the control of the trout RBC beta-AR Na+/H+ exchanger (beta-NHE) activity by signaling through this beta3b-subtype and not through a beta1-subtype as previously proposed. The RBC-specific trout beta3b-AR exhibits binding characteristics that distinguish this receptor from each of the three pharmacologically defined categories of mammalian beta-ARs (beta1-, beta2-, and beta3-AR). This study is the first to report the presence of a beta3-AR subtype in a fish species, and the proposal that the beta3b-AR controls RBC beta-NHE activity represents a novel role for the beta3-AR subtype in vertebrates.
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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".