Sex and aging interact to modulate the rapid onset of arteriolar dilation in mouse skeletal muscle
Bibliographic record
Abstract
Aging is associated with a reduction in blood flow to skeletal muscle and diminished exercise capacity. However, little is understood of how aging affects arteriolar dynamics in working skeletal muscle. We tested the hypothesis that aging impairs the rapid onset of vasodilation (ROV) in mouse gluteus maximus muscle. Responses of second‐order arterioles [diameter: rest, 17 ± 1 μm; max (SNP), 29 ± 1 μm] to single tetanic contractions (100 Hz) were assessed in anesthetized C57Bl/6 mice using intravital microscopy in Young (3 mo) males (YM; n=7) and females (YF; n=5) and in Old (~20 mo) males (OM; n=7) and females (OF; n=6). With increasing stimulus duration (100–1000 ms), the magnitude of dilation increased (from 1 to 7 μm) in YM, YF, and OF (P<0.05) yet ROV was blunted consistently by >50% in OM (P<0.05). In contrast, 30‐s rhythmic contractions at 2, 4, and 8 Hz resulted in steady‐state dilations that increased with frequency (from 2 to 8 μm; P<0.05) and were not different between groups. Remarkably, the decrement in ROV in OM was reversed (P<0.05) with α‐adrenoreceptor blockade (1 μM phentolamine). These data support the hypothesis that aging selectively impairs ROV in Old male mice through increased activation of α‐adrenoreceptors. (NIH R21‐AG19347 and HSFC)
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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 | 0.001 | 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".