PLASMA ERYTHROPOIETIN CONCENTRATION DETERMINE THE CAROTID BODY CHEMOSENSITIVITY TO HYPOXIA AND HYPERCAPNIA IN RATS
Bibliographic record
Abstract
We tested the hypothesis that Erythropoietin (Epo) have an impact in the modulation of carotid body (CB) chemoreceptors in response to hypoxia and hypercapnia. To study this subject, we used isolated and perfused ex vivo CB preparations from adult male Sprague Dawley rats. Prior evaluation of the carotid sinus nerve activity (CSNA ‐ throughout a suction glass electrode encircling and sealing the junction of the carotid body and the carotid sinus nerve), preparations were incubated for 1h with (or without) Epo at different concentrations. Then CBs were exposed to hypoxic and hypercapnic conditions. Normoxic baseline activity was not affected by any tested Epo concentration. However, under hypoxia and hypercapnia, Epo doses lower than 0.5U/ml increased the CSNA (by almost 40%), Epo doses higher than 0.5U/ml gradually decreased the CSNA in hypoxic and hypercapnic condition. Complete inhibition of CSNA was reached when preparations were incubated with 2U/ml of Epo concentration. Keeping in mind that nitric oxide (NO) in CB is an inhibitory messenger and that Epo in combination with low oxygen tension increase the endothelial capacity to produce NO, preparations were incubated at the same time with Epo (at the inhibitory concentration of 1 U/ml) and NO inhibitors, 400 μM L‐NAME (Nitric synthase inhibitor) or 100 μM 7NI (specific neuronal Nitric oxide synthase inhibitor). Our results showed that inhibition of NO (with L‐NAME and 7NI) fully restored the hypoxic CSNA. Similar results were found by exposing CB preparations to hypercapnic conditions. Accordingly, to these findings, immunohistochemistry studies showed a dense staining of Epo receptors (EpoR) in the carotid bodies, apparently localized within islets of chemosensitive cells. In summary, our results strongly suggest that the plasma Epo concentration determines the CB chemo‐response to hypoxic and hypercapnic conditions. These novel findings are relevant to better understand respiratory disorders, including those occurring at high altitude. Support or Funding Information CIHR, Région Rhône Alpes and consulat de France in Québec This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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".