Dopamine receptor blockade improves pulmonary gas exchange during exercise in healthy humans (717.1)
Bibliographic record
Abstract
Impaired pulmonary gas exchange during heavy exercise, manifested as an increase in the alveolar‐arterial oxygen difference (A‐aDO 2 ), may be due to anatomical intrapulmonary (IP) shunt recruitment. Dopamine (DA) has been shown to recruit IP shunts at rest and circulating DA increases with exercise, and thus may contribute to the increased A‐aDO 2 during exercise. We hypothesized that gas exchange impairment during exercise will decrease with DA receptor blockade. Ten healthy males (Age: 25±6 yrs, VO 2max : 56.3±6.6 ml∙kg ‐1 ∙min ‐1 ) performed two incremental staged cycling exercise sessions after ingestion of either placebo (P) or DA blockade (B) (Metoclopramide 20mg). Arterial blood gas sampling and cardiorespiratory data were obtained at rest and during 4 exercise intensities (30%, 50%, 75% and 90% of previously determined VO 2max ). At 90% VO 2max , DA blockade decreased A‐aDO 2 (P: 19.3±8.5 torr, B: 14.8±6.8 torr, p =0.038 and increased arterial O 2 saturation (P: 95.4±1.0%, B: 96.2±0.9%, p =0.004). Blood gases were similar between the two groups at rest, 30%, 50% and 75% of VO 2max . Compared to placebo, DA blockade did not change O 2 consumption, CO 2 production, or respiratory exchange ratio at any intensity. Administration of a DA receptor blockade decreased A‐aDO 2 during near‐maximal exercise, suggesting that endogenous DA affects affects pulmonary gas exchange during exercise. Grant Funding Source : Supported by The National Sciences and Engineering Research Council of Canada
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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) | 0.001 | 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) | 0.002 | 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".