Adrenergic regulation of catecholamine secretion from trout (Oncorhynchus mykiss) chromaffin cells
Bibliographic record
Abstract
The interaction between extracellular catecholamines and catecholamine secretion from chromaffin cells was assessed in rainbow trout (Oncorhynchus mykiss) using an in situ saline-perfused posterior cardinal vein preparation. This was accomplished by comparing the effects of adrenergic receptor agonists and antagonists on stimulus-evoked secretion. An acute bolus injection or extended perfusion with saline containing high levels of either noradrenaline or adrenaline did not affect the baseline secretion of catecholamines. However, catecholamine secretion in response to a bolus injection of the general cholinergic receptor agonist carbachol or electrical stimulation of the nerves innervating the chromaffin cells was abolished or reduced respectively, in preparations perfused with saline containing either catecholamine. To characterize the catecholaminergic inhibition of catecholamine release, secretion in response to carbachol and electrical stimulation was compared in preparations perfused with the adrenergic receptor agonists dobutamine (beta(1)), salbutamol (beta(2)), phenylephrine (alpha(1)) or clonidine (alpha(2)). Prior treatment with dobutamine or phenylephrine was without effect on baseline catecholamine secretion or stimulus-evoked secretion. In contrast, pre-treatment with salbutamol significantly inhibited catecholamine secretion in response to carbachol or electrical stimulation. Pre-treatment with clonidine did not affect carbachol-evoked secretion but did reduce catecholamine secretion during electrical stimulation. The significance of this adrenergic mechanism of regulating stimulus-evoked catecholamine secretion was further established using the adrenergic receptor antagonists nadolol (beta) or phentolamine (alpha). Catecholamine secretion in response to cholinergic stimulation was significantly enhanced in preparations perfused with saline containing nadolol. Furthermore, pre-treatment with phentolamine significantly enhanced adrenaline secretion in response to neuronal stimulation. These results suggest that the mechanisms of adrenergic inhibition of catecholamine secretion from trout chromaffin cells include activation of chromaffin cell membrane beta(2)-receptors and presynaptic alpha(2)-adrenergic receptors.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".