ROS scavenging mimics anoxia by enhancing GABA receptor‐mediated electrical suppression in anoxia‐tolerant turtle cortex
Bibliographic record
Abstract
In anoxic mammalian brain, ATP dependent ion pumping is compromised and the consequent loss of membrane ion gradients elicits hyper‐excitability and cell death. This does not occur in the western painted turtle brain, where γ‐aminobutyric acid (GABA) concentration increases 80 fold and electrical activity decreases 75–95%. During anoxia, electrical suppression results from increased GABA receptor (GABAR)‐mediated postsynaptic currents (PSC) that shunt excitatory current, thereby avoiding excess AP firing. The signaling pathway responsible for initiating GABAergic neuroprotection is unknown but could involve decreases in the concentration of reactive oxygen species (ROS) that occurs following onset of anoxia. Using whole‐cell and perforated patch clamp techniques we determined that, similar to anoxia, ROS scavenging caused: whole cell conductance to increase from 4.5 ±0.4 to 6.6 ±1.1 nS; AP threshold to depolarize from 45 ± 4.2 to 24 ± 2.2 mV; and GABAR‐mediated currents to double in amplitude from 237.8 ± 81.6 to 449.8 ± 136.9 pA. Pharmacological anoxia (normoxic plus cyanide) caused a similar increase in GABAR current amplitude to 407.8 ± 38.5 pA and this was prevented by ROS donors (hydrogen peroxide or xanthine oxidase/xanthine). We conclude that a decrease in mitochondrial ROS production is the signal that increases GABAR currents during anoxic stress. Research supported by OGS scholarship to DWH, NSERC postdoctoral fellowship to MEP and an NSERC Discovery and Accelerator Grant to LTB.
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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".