Development of Autonomic Dysreflexia after Spinal Cord Injury Is Associated with a Lack of Serotonergic Axons in the Intermediolateral Cell Column
Bibliographic record
Abstract
Autonomic dysreflexia consistently develops in patients and in rats after severe upper thoracic spinal cord injury (SCI) as a result of exaggerated spinal sympathetic excitation. In this study we induced episodic hypertension in rats after varying degrees of SCI severity to investigate the contribution of serotonergic bulbospinal axons to the development of autonomic dysreflexia after SCI. Female Wistar rats (250-300 g) were used in all experiments in the following groups: (1) uninjured, (2) clip compression at T4 of 20, 35, or 50 g, (3) spinal cord transection at T4, and (4) intrathecal 5,7-dihydroxytryptamine creatinine sulfate (5,7-DHT). Immunohistochemistry for choline acetyl transferase and serotonin (5-HT) was performed on T8-T12 spinal segments to identify sympathetic preganglionic neurons, and to assess 5-HT-containing axons in the intermediolateral cell column (IMLC), respectively. Testing for autonomic dysreflexia was conducted by measuring mean arterial pressure (MAP) at rest and after colon distension-induced hypertension. We observed that the magnitude of the pressor response seen after colon distension correlated with SCI severity and density of 5-HT-immunoreactive axons in the IMLC. Intrathecal administration of the 5-HT(2A) agonist dimethoxy-4-iodamphetamine increased resting MAP and blocked colon distension-induced hypertension, whereas the 5-HT(2A) antagonist ketanserin decreased resting MAP and was permissive to the colon distension-induced pressor response in SCI rats. These results suggest that the SCI-induced loss of serotonergic inputs into the spinal cord IMLC is proportional to the pathogenesis of autonomic dysreflexia and hypotension seen after SCI. We thus conclude that sparing of serotonergic axons beyond a critical threshold preserves cardiovascular regulation and prevents the development of autonomic dysreflexia.
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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".