The Anoxic Reduction of Mitochondrial ROS Production Leads to Increased GABAergic Interneuron Activity and Electrical Suppression in Turtle Cerebral Cortex
Bibliographic record
Abstract
The anoxia‐tolerant western painted turtle ( Chrysemys picta bellii) has uniquely adapted to surviving extended periods of low O 2 by reducing the activity of energy‐consuming pathways. The largest such pathway is the re‐establishment of neuronal ionic gradients following excitatory transmission. We hypothesize that the mitochondria serve as the initiator of neuronal silencing by sensing changes in O 2 and triggering increased GABA release with the goal of reducing overall energetic demand. Here, we show that the reduction of mitochondrial O 2 consumption during anoxia limits the production of reactive oxygen species (ROS), as evidenced by a fluorescence reduction of the ROS‐sensitive dye DCF during anoxia. Whole‐cell patch clamp recordings demonstrate that this reduction in ROS enhances both tonic and phasic post‐synaptic GABA A receptor currents. To determine how the reduction in ROS affects GABA release, we first determined the location of neurons that produce and release GABA. Fast‐spiking GABA‐releasing stellate interneurons were found to sparsely reside in the molecular and subcellular layers of the turtle cortex, based in immunohistochemical staining for glutamate decarboxylase and the voltage‐sensitive K + channel subunit Kv3.1. These neurons fire action potential bursts at a frequency of 0.09 ± 0.01 Hz, which is the same frequency that GABAergic phasic currents occur in pyramidal neurons. Following the transition to anoxia or during pharmacological ROS scavenging with N‐acetylcysteine, stellate interneurons depolarize and become more excitable, as evidenced by the increased prevalence of action potentials between and during bursts. These results suggest that mitochondrial ROS signaling in stellate interneurons controls widespread GABAergic signaling in the turtle cortex. Support or Funding Information Research was supported by an Ontario Graduate Scholarship to Peter Hawrysh and a Discovery Accelerator Supplements NSERC grant to Les Buck.
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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".