Activity of muscle sympathetic neurons during normotensive pregnancy
Bibliographic record
Abstract
In pathological populations, elevated sympathetic activity is associated with increased activity of individual sympathetic neurons. We used custom action potential detection software to analyze multiunit sympathetic activity in 18 normotensive pregnant women (third trimester; 33 ± 5 wk) and 19 nonpregnant women at rest and a subset (10 and 13, respectively) during a cold pressor challenge. Although the number of action potentials per burst and number of active amplitude-based “clusters” were not different between groups, the total number of sympathetic action potentials per minute was higher in pregnant women at rest. Individual clusters were active predominately once per burst, suggesting they represent single neurons. Action potentials occurred in closer succession in normotensive pregnant (interspike interval 36 ± 10 ms) versus nonpregnant women (50 ± 27 ms; P < 0.001) at rest. Pregnant women had a lower total peripheral resistance (11.7 ± 3.0 mmHg·l−1·min) than nonpregnant women (15.1 ± 2.7 mmHg·l−1·min; P < 0.001), indicating a blunted neurovascular transduction. The cold pressor reduced the number of action potentials per burst in both groups due to shortening of the R-R interval in conjunction with increased burst frequency; total neural firing per minute was unchanged. Thus elevated sympathetic activity during normotensive pregnancy is specific to increased incidence of multiunit bursts. This is likely due to decreased central gating of burst output as opposed to generalized increases in central drive. These data also reinforce the concept that pregnancy appears to be the only healthy state of chronic sympathetic hyperactivity of which we are aware.
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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 | 0.001 |
| 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) | 0.000 | 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 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".