Pulmonary arterial mechanoreceptors modulate exercise‐induced sympathetic activation in healthy humans during moderate‐intensity hypoxic exercise
Bibliographic record
Abstract
Abstract Central command, muscle afferent feedback and arterial baroreceptors all contribute to sympathetic vasoconstrictor activity during moderate‐intensity dynamic exercise in humans; however, whether a causal link exists between pulmonary arterial mechanoreceptors and sympathetic outflow directed to inactive skeletal muscle (muscle sympathetic nerve activity, MSNA) remains to be explored. Twelve participants (28 ± 7 years, 2 females) performed two 6 min exercise bouts (heart rate ∼ 120∙beats∙min −1 ) in hypoxia (FiO 2 = 12.5%) to elevate pulmonary artery pressure (PAP) above normal, whilst MSNA (microneurography), systemic blood pressure (photoplethysmography, BP), oxygen saturation (SpO 2 ) and minute ventilation (V E ) were measured continuously. Systolic PAP was estimated using Doppler echocardiography. In one trial nitric oxide was added to the inhaled air (iNO, 40 parts per million) to selectively dilate the pulmonary vasculature and reduce exercise PAP. MSNA burst frequency was supressed (30 ± 9 vs . 34 ± 9 bursts∙min −1 ; p = 0.03) when exercise systolic PAP was lowered (36.8 vs . 42.9 ± 8 mmHg; p = 0.02). MSNA burst incidence (index of sympathetic baroreflex operating point) was reduced (25 ± 8 vs . 28 ± 9 bursts∙100 heartbeats −1 ; p = 0.03) without any change in corresponding diastolic BP or spontaneous baroreflex gain. Mean BP, SpO 2 and V E did not differ between trials. Together these data support a mechanistic link between pulmonary arterial mechanoreceptor activation and neurocirculatory control during hypoxic exercise. The effect of pulmonary arterial mechanoreceptor activity on exercise‐induced sympathetic activation and baroreflex resetting may have consequences for sympathetic vasomotor outflow (dys)regulation in health and disease where PAP is elevated. image Key points Pulmonary arterial pressure increases proportionally to cardiac output during dynamic exercise; this pressure rise may contribute to excitation of sympathetic vasoconstrictor activity directed to skeletal muscle (muscle sympathetic nerve activity, MSNA) via stimulation of pulmonary arterial mechanoreceptors. In this study addition of nitric oxide to hypoxic inspired air (FiO 2 = 12.5%) reduced pulmonary arterial pressure during sub‐maximal cycling exercise; this coincided with reduced MSNA burst frequency (vasoconstrictor outflow) and burst incidence (operating point for baroreflex control of vasoconstrictor outflow). These findings demonstrate that a signal from pulmonary arterial mechanoreceptors is involved in sympathoexcitation during hypoxic exercise. Furthermore this mechanism could be relevant clinically in pulmonary and cardiac diseases associated with pulmonary hypertension and exaggerated sympathoexcitation during exercise.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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) | 0.000 | 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".