Colocalisation of Dynorphin A and Neurokinin B Immunoreactivity in the Arcuate Nucleus and Median Eminence of the Sheep
Bibliographic record
Abstract
Dynorphin A (DYN)-containing cells play a key role in conveying the negative feedback influence of progesterone upon pulsatile gonadotrophin-releasing hormone (GnRH) secretion in the ewe. A very high percentage of DYN cells in the arcuate nucleus express the progesterone receptor; another population of arcuate nucleus cells that also express steroid receptors in the sheep are those that express the tachykinin peptide, neurokinin B (NKB). Both DYN and NKB fibres have been shown to form close contacts with ovine GnRH cells. Therefore, the present study tested the hypothesis that neurones expressing NKB and DYN represent the same neuronal population in the arcuate nucleus. Confocal microscopic analysis of brain sections processed for dual immunofluorescence revealed that a large majority of DYN neurones in the arcuate nucleus were also immunoreactive for NKB. Likewise, a similar majority of NKB neurones in the arcuate nucleus were immunoreactive for DYN. By contrast, DYN cells in the preoptic area and anterior hypothalamus did not colocalise with NKB, nor did DYN cells in the paraventricular or supraoptic nuclei. Fibres that stained positively for both DYN and NKB were seen in the arcuate nucleus, where they formed close appositions with DYN/NKB-positive neurones, and in the external zone of the median eminence. Taken together with previous findings, these data suggest that a subpopulation of arcuate nucleus neurones coexpressing DYN and NKB mediate the negative feedback influence of progesterone on pulsatile GnRH secretion in the ewe and may also be involved in other feedback actions of gonadal steroids.
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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".