Reduced osmoresponsiveness in magnocellular neuroendocrine neurones during chronic salt‐loading
Bibliographic record
Abstract
, which is much less than expected from the hyperosmolality induced by saltloading. The neuronal responsiveness to acute osmotic stimuli was also markedly impaired, with no change in their responses to non-osmotic stimuli. We then undertook a systematic search of the literature for studies in salt-loaded rats that had measured oxytocin or vasopressin secretion, plasma osmolality, haematocrit or pituitary hormone content, and reviewed them in light of our electrophysiological findings. The prevailing understanding is that salt loading induces plastic changes in neuronal behaviour to promote exaggerated vasopressin secretion, but the conclusions that we draw from our electrophysiological findings in urethane-anaesthetized rats and the literature review suggest the converse - that vasopressin neurones selectively habituate to osmotic stimuli, presumably to conserve diminished pituitary stores of vasopressin while sustaining enough secretion for maximal renal effects. KEY POINTS: Seven days of 'salt-loading' produces a large increase in plasma osmolality and depletes the pituitary content of vasopressin and oxytocin, apparently reflecting enhanced secretion. Using in vivo electrophysiological recordings in urethane-anaesthetized rats, we show that, after 7 days of salt loading, the basal firing rate of both vasopressin and oxytocin cells was increased to a much lesser extent than expected from the hyperosmolality induced by acute osmotic stimuli. The neuronal responsiveness to acute osmotic stimuli was also markedly impaired with no change in their responses to non-osmotic stimuli. Our results show that these neurones strongly and selectively habituate to chronic osmotic stimuli, presumably to conserve diminished pituitary stores of hormone. Our conclusions contradict the prevailing understanding that salt loading promotes an exaggerated hyperexcitability of the hypothalamo-neurohypophysial system.
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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".