Potential roles of ATP and local neurons in the monitoring of blood O<sub>2</sub> content by rat aortic bodies
Bibliographic record
Abstract
New Findings What is the central question of this study? How do aortic bodies monitor blood O 2 content? We investigated whether ATP, known to be released from red blood cells during hypoxia, could contribute via interactions with local neurons. What is the main finding and its importance? In dissociated aortic body cultures from the vagus and recurrent laryngeal nerves, some local neurons expressed functional P2X2/3 purinoceptors and were electrically coupled; there was also the potential for cholinergic neurotransmission. Large molecules, such as Evans Blue, had easy access to local neurons via the circulation. We hypothesize that sensing of low blood O 2 content may involve ATP release from red blood cells, leading to stimulation of local ‘sensory’ aortic body neurons. Aortic bodies are arterial chemoreceptors presumed to monitor blood O 2 content by unknown mechanisms, in contrast to their well‐studied carotid body counterparts, which monitor and /pH. We recently showed that rat aortic body chemoreceptors (type I cells), located at the left vagus–recurrent laryngeal nerve bifurcation, responded to and /pH in a manner similar to carotid body type I cells. These aortic bodies are uniquely associated with a group of local neurons, which are also sensitive to these stimuli. Here, we hypothesized that these local neurons may contribute to monitoring blood O 2 content. During perforated patch recordings, ATP, known to be released from (carotid body) type I cells and red blood cells during hypoxia, induced inward currents and excited ∼45% of local neurons (EC 50 ∼1 μ m ), mainly via heteromeric P2X2/3 purinoceptors. While ATP also induced a rise in intracellular [Ca 2+ ] in a subpopulation of these neurons, almost all of them responded to nicotinic cholinergic agonists. During paired recordings, several juxtaposed neurons showed strong bidirectional electrical coupling, suggesting a local co‐ordination of electrical activity. Perfusion with Evans Blue dye resulted in labelling of aortic body paraganglia, suggesting they have ready access to circulatory factors, e.g. ATP released from red blood cells during hypoxia. When combined with confocal immunofluorescence, the dye‐labelled regions coincided with areas containing tyrosine hydroxylase‐positive type I cell clusters and P2X2‐positive nerve endings. We propose a working model whereby local neurons, red blood cells, ATP signalling and low blood flow contribute to the unique ability of the aortic body to monitor blood O 2 content.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".