Methylxanthine reversal of opioid‐induced respiratory depression in the in situ neonatal rat working heart‐brainstem preparation
Bibliographic record
Abstract
Methylxanthines, such as caffeine and theophylline, are commonly given to premature infants to counter apneas of prematurity, but the mechanism by which these drugs prevent apnea is poorly understood. Methylxanthines act as nonselective adenosine receptor antagonists at lower concentrations and nonselective phosphodiesterase inhibitors at higher concentrations. Previous work in en bloc and slice preparations has demonstrated that >1 mM theophylline can reverse breathing suppressed by the μ‐opioid receptor agonist DAMGO. Using the in situ neonatal rat working heart‐brainstem preparation (a more intact preparation than previously employed) we show that theophylline restores DAMGO‐suppressed respiration in doses <1 mM, starting to effectively restore respiration at 250 μM. Denervation of the carotid bodies did not alter the response, suggesting that the response to theophylline is mediated centrally. These experiments suggest that in vivo , block of adenosine receptors may be involved in countering opioid depression. Funded by CIHR and Hotchkiss Brain Institute (EVF)
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".