Blockade of the 5‐HT<sub>3</sub>receptor for days causes sustained relief from mechanical allodynia following spinal cord injury
Bibliographic record
Abstract
Chronic neuropathic pain is a frequent, serious outcome of spinal cord injury (SCI) that is highly refractory to treatment. Serotonin can contribute to neuropathic pain after SCI, as suggested by our previous observation that transient blockade of the 5-HT(3) receptor by intrathecal injections of the antagonist ondansetron reduces mechanical allodynia after SCI in rats. The current study determined whether intrathecal or intravenous infusion of ondansetron for 3 or 7 days, respectively, could cause sustained blockade of mechanical allodynia at and below the level of a twelfth thoracic clip compression injury in rats. Intrathecal 3-day infusion of ondansetron (2.0 microg/hr), targeted to the cord rostral to the SCI and commencing at 28 days after SCI, decreased at-level mechanical allodynia by 40% and below-level allodynia by 60% compared with saline-treated rats (controls). This reduction was sustained throughout drug delivery and for 1 day afterward. During the next 3 days, allodynia gradually returned toward the values of saline-treated rats. An initial experiment showed that bolus intravenous injections of ondansetron (20-100 microg) at 28 days after SCI decreased both at- and below-level allodynia for 90-120 min. Intravenous 7-day infusions (20 microg/hr), commencing at 28 days after SCI, significantly decreased at-level allodynia by 48% and below-level allodynia by 51% compared with controls. This reduction of allodynia lasted throughout the infusion and for 1-3 days afterward while pain responses gradually approached those of controls. These findings suggest a potential role of 5-HT(3) receptor antagonism in the relief of neuropathic pain after SCI in humans.
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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 | 0.000 | 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".