Medial Septal Cholinergic Neurons Modulate Isoflurane Anesthesia
Bibliographic record
Abstract
BACKGROUND: Cholinergic drugs are known to modulate the response of general anesthesia. However, the sensitivity of isoflurane or other volatile anesthetics after selective lesion of septal cholinergic neurons that project to the hippocampus is not known. METHODS: Male Long Evans rats had 192 immunoglobulin G-saporin infused into the medial septum (n = 10), in order to selectively lesion cholinergic neurons, whereas control, sham-lesioned rats were infused with saline (n = 12). Two weeks after septal infusion, the hypnotic properties of isoflurane and ketamine were measured using a behavioral endpoint of loss of righting reflex (LORR). Septal lesion was assessed by counting choline acetyltransferase-immunoreactive cells and parvalbumin-immunoreactive cells. RESULTS: Rats with 192 immunoglobulin G-saporin lesion, as compared with control rats with sham lesion, showed a 85% decrease in choline acetyltransferase-immunoreactive, but not parvalbumin-immunoreactive, neurons in the medial septal area. Lesioned as compared with control rats showed increased isoflurane sensitivity, characterized by a leftward shift of the graph plotting cumulative LORR percent with isoflurane dose. However, lesioned and control rats were not different in their LORR sensitivity to ketamine. When administered with 1.375% isoflurane, LORR induction time was shorter, whereas emergence time was longer, in lesioned as compared with control rats. Hippocampal 62-100 Hz gamma power in the electroencephalogram decreased with isoflurane dose, with a decrease that was greater in lesioned (n = 5) than control rats (n = 5). CONCLUSIONS: These findings suggest a role of the septal cholinergic neurons in modulating the sensitivity to isoflurane anesthesia, which affects both induction and emergence. The sensitivity of hippocampal gamma power to isoflurane appears to indicate anesthesia (LORR) sensitivity.
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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 | 0.000 |
| 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".