Spinal Carbonic Anhydrase Contributes to Nociceptive Reflex Enhancement by Midazolam, Pentobarbital, and Propofol
Bibliographic record
Abstract
BACKGROUND: Systemic administration of acetazolamide blocks nociceptive hyperreflexia induced by pentobarbital. The authors assessed the effect of intrathecal carbonic anhydrase inhibitors (CAIs) on nociceptive reflex enhancement by pentobarbital, propofol, and midazolam. METHODS: Twenty-seven rats with chronic indwelling subarachnoid catheters were studied. Nociceptive paw reflex latency (PWL) for paw withdrawal from radiant heat was measured in forelimbs and hind limbs. Measurements were obtained under control conditions, 15 min after lumbar intrathecal injection of 10 microl artificial cerebrospinal fluid containing the CAIs acetazolamide or ethoxyzolamide, and during the 55 min after intraperitoneal injection of three sedative drugs: 30 mg/kg pentobarbital, 50 mg/kg propofol, or 1.9 mg/kg midazolam. RESULTS: Control values of PWL averaged 10.9 +/- 1.5 s in the forelimbs and 11.1 +/- 1.6 s in the hind limbs (P = 0.18). Intrathecal injection of 50 microm ethoxyzolamide reduced PWL by 8% and 4% in the forelimbs and hind limbs, respectively (P = 0.01); all other CAI injections had no effect on PWL. Following anesthetic injection, PWL in the forelimbs was reduced by approximately 35-40% of control values; in the hind limbs, CAI treatment decreased the PWL reduction to 8-16% for pentobarbital (P < 0.001), 30-32% for propofol (P < 0.02), and 9-16% for midazolam (P < 0.001). The hind limb reduction of hyperreflexia by CAI was less for propofol than for midazolam or pentobarbital (P < 0.002). CONCLUSION: Spinal carbonic anhydrase contributes to nociceptive hyperreflexia induced by pentobarbital and midazolam and to a lesser extent with propofol. These findings are consistent with a role for carbonic anhydrase in nociceptive signal enhancement by these drugs.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".