Effect of Sex on Sympatho-inhibitors and Non-inhibitor Phenotypes during Acute Hyperoxia
Bibliographic record
Abstract
Acute hyperoxia (i.e., breathing air consisting of 100% oxygen, O 2 ) reduces muscle sympathetic nerve activity (MSNA), positioning hyperoxia as a potential anti-hypertensive therapeutic. However, the link between hyperoxia and MSNA has not been established in females. We tested the hypothesis that males would exhibit greater reductions in MSNA during hyperoxia than females. We tested healthy females (n=18, 27±5yr, body mass index [BMI] 23±3kg/m 2 ) and males (n=13, 27±5yr, 25±3kg/m 2 ) of similar age (P=0.99) and BMI (P=0.08). Integrated MSNA, blood pressure, and end-tidal O 2 (ET O2 ) and CO 2 (ET CO2 ) were measured during normal room air breathing (BSL; 3-min) and hyperoxic breathing (100% O 2 ; 3-min). Integrated MSNA was quantified as burst frequency (BF; bursts/min), amplitude (BA; a.u.), and total MSNA (a.u.); blood pressure was quantified as mean arterial pressure (MAP). Baseline MSNA BF was not different between females and males (24±7 vs 23±8 bursts/min, respectively, P=0.68); MAP was lower in females than males (85±7 vs 93±7 mmHg; p<0.01). Hyperoxia increased ET O2 (effect of cond: p<0.01) and reduced ET CO2 (effect of cond: p<0.01) in a manner similar between sexes for ET O2 (sex*cond: P=0.56) whereas ET CO2 decreased more in females than males (sex*cond: P=0.01). Overall, hyperoxia evoked reductions in MSNA BF (effect of cond: P=0.02) but not BA (effect of cond: P=0.80) or total MSNA (effect of cond: P=0.26). Nadir MSNA responses during hyperoxia unveiled sex differences insofar as total MSNA was reduced consistently only in males (sex*cond: P=0.04); within the females we observed the presence of sympatho-inhibitors and non-inhibitors. Whereas female and male inhibitors reduced total MSNA via substantial reductions in BF and non-significant reductions in BA, female non-inhibitors demonstrated limited reductions in BF (P=0.11 vs inhibitors) coupled with increases in BA (p<0.01 vs inhibitors), resulting in no net change in total MSNA (p<0.01 vs inhibitors). Overall, these findings indicate sex differences exist in the sympathetic response to hyperoxia, in marked variability in the female sympathetic response to acute hyperoxia. The Women and Children's Health Research Institute. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
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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) | 0.003 | 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".