Spinal nerve injury activates prostaglandin synthesis in the spinal cord that contributes to early maintenance of tactile allodynia
Bibliographic record
Abstract
To determine if spinal prostaglandins (PG) contribute to tactile allodynia, male, Sprague-Dawley rats were fitted with either intrathecal (i.t.) microdialysis or drug delivery catheters 3 days before tight ligation of the left lumber 5/6 spinal nerves. Paw withdrawal thresholds (PWT) were determined using von Frey filaments. Ligated rats developed tactile allodynia within 24h, as evidenced by a decrease in PWT in the affected hindpaw (<4 g vs. >15 g control). Sham-operated controls were unchanged from baseline (>15 g). Allodynia was also characterized by a significant increase in the evoked release of PGE(2). Thus, brushing the plantar surface of the affected hindpaw with a cotton-tipped applicator, 5 days postligation, increased the [PGE(2)](dialysate) to 199+/-34% of the prestimulus control period. In contrast, brushing had no detectable effect on release before surgery or in sham-operated animals. Basal release (no brushing) was similar before and after surgery (sham-operated and ligated rats). In a separate group of rats and beginning 2 days after ligation, the acute i.t. injection of S(+)-ibuprofen, SC-51322, SC-236, or SC-560 significantly reversed allodynia (maximum effect=69+/-9, 66+/-6, 57+/-4, 20+/-5%, respectively). R(-)-ibuprofen or vehicle were without effect. The results of this study suggest that: (a). spinal PG synthesis and allodynia-like behaviour are triggered by normally innocuous brushing after spinal nerve ligation; (b). pharmacological disruption of this cascade significantly reverses allodynia; (c). COX-2 is the relevant isozyme; and (d). the PG effect is mediated by spinal EP receptors.
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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) | 0.001 | 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 | 0.001 | 0.001 |
| 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".