Multiphoton calcium imaging of methylxanthine‐reversal of opioid depression of inspiratory‐related pre‐Bötzinger complex rhythm in newborn rat brainstem slices
Bibliographic record
Abstract
Breathing depression by opioids is reversed by methylxanthines (e.g. theophylline). Opioids block Ca2+ channels while methylxanthines cause Ca2+ release from cellular stores at high doses. We studied in newborn rat brainstem slices with 2photon imaging whether opioid block of inspiratory center pre‐Bötzinger Complex (preBötC) and its recovery by theophylline involved cytosolic Ca2+ change. DAMGO blocked bursting and related Ca2+ rises in most preBötC neurons. Ca2+ baseline fell by ~10% in these cells, but not in presumed astrocytes. Theophylline and phosphodiesterase‐4 (PDE4) blocker Rolipram restored rhythm with no effect on Ca2+ baseline. Ca2+ store blocker cyclopiazonic acid did not raise the baseline in preBötC neurons, but in astrocytes. Ca2+ rises became irregular upon block of L‐type Ca2+ channels with nifedipine or Ni2+(0.1mM) without effect on Ca2+ baseline or rhythm. At 2.5mM, Ni2+ blocked rhythm and Ca2+ baseline fell by 10%. Summary Opioid depression is associated with a Ca2+ fall in preBötC cells that is not due to block of L‐type Ca2+ channels whereas actions of methylxanthines or PDE4 blockers do not involve a major change in Ca2+. Supported by CIHR, AHFMR, CFI‐ISRIP, MFN Health
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.002 | 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".