Central Pain Following a Collagenase-Induced Hematoma in the Basal Ganglia and Thalamus Can Be Reversed with Gabapentin
Bibliographic record
Abstract
The objective of this study was to evaluate pain sensitization in rats following the induction of an intracerebral haemorrhage located in the basal ganglia and/or thalamus using the Rosenberg model (intracerebral injection of collagenase). Thirty male Sprague-Dawley rats weighing between 175-300 g were used. In a first experiment, 3 groups of 6 animals were used to evaluate pain threshold using the Hargreaves test (thermal sensitivity). Following 3 days of behavioural testing (baseline values), animals in each group were injected intracerebrally either with 0.5, 1 or 2 μL of a collagenase solution (0.5 U/2 μL Type VII collagenase) which induced a hematoma in the right caudoputamen nucleus and/or thalamus. They were then tested for the next 9 consecutive days. No pain-related behavioural changes were observed following injections with 0.5 and 1 μL of collagenase. However with 2 μL, reaction times were significantly faster on days 3, 4, 5, 6 (p < 0.0001) and 7 (p < 0.006) in the right and left hind paws compared to baseline values. The lesion was localized only in the caudoputamen nucleus for animals receiving 0.5 and 1 μL of collagenase whereas lesions extended in the ipsilateral thalamic nuclei (lateral-dorsal and lateral-posterior nuclei) for animals receiving 2 μL of collagenase. In a second experiment, gabapentin reversed mechanical allodynia, evaluated with von Frey filaments, and hyperalgesia, evaluated with Hargreaves test, in rats (n=6) following a collagenase-induced (3 μL) hematoma. In conclusion, these preliminary results suggest that central pain was induced in rats with a collagenase-induced intracerebral haemorrhage localized in the caudoputamen nuclei most probably associated with lesions to the thalamus, and concurrent allodynia and hyperalgesia were reduced with gabapentin treatment.
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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 | 0.001 |
| 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".