Arteriolar dilations induced by contraction of hamster cremaster muscle are dependent on changes in endothelial cell calcium
Bibliographic record
Abstract
UNLABELLED: Muscle contraction initiates microvascular arteriolar dilation in regions directly overlapping the active fibres but the cells (vascular smooth muscle cells, endothelial cells) responsible for producing the dilation and the underlying signalling mechanisms are unknown. AIMS: We tested the hypothesis that changes in endothelial cell calcium (Ca2+) are involved in this dilation. METHODS: Four to five muscle fibres lying approximately perpendicular to arterioles (maximum diameter approximately 40 microm) were stimulated (4 Hz, 4-20 V, 0.4 ms duration) and observations were made at the site of muscle fibre/arteriole overlap. RESULTS: Chelation of endothelial cell Ca2+ (with BAPTA) abolished dilations to 120 s of muscle contraction (5.6 +/- 1.5 microm in controls vs. 0.51 +/- 1.2 microm with BAPTA, n = 6), indicating that changes in endothelial cell Ca2+ are required for the response. To determine the time frame of the Ca2+ signal, we monitored whole endothelial cell Ca2+ (with Fura-PE3) prior to and following either 120 (n = 13), 30 (n = 9) or 10 (n = 9) s of muscle contraction. In all instances, no changes in Ca2+ were observed despite typical dilator responses. CONCLUSIONS: These data indicate that (i) the initiation of muscle contraction-induced arteriolar dilations depends on a change in endothelial cell Ca2+, which must be a transient event that takes place early/during stimulation, and (ii) maintenance of the dilation after contraction occurs via mechanisms that are independent of changes in global Ca2+ within the cell.
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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 | 0.000 | 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) | 0.000 | 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".