Effects of Phenylephrine and Norepinephrine on the Diameter of the Epineurial Vessels Supplying the Sciatic Nerve
Bibliographic record
Abstract
Background Phenylephrine (PE) and norepinephrine (NE) are known vasoconstrictors; however, little is known about their role in blood flow regulation at the sciatic nerve. The purpose of this study was to determine the effects of PE and NE on the epineurial vessels supplying the sciatic nerve. Methods Adult male Sprague‐Dawley rats (323.1 ± 5.2 g) were anaesthetized using urethane, α‐chloralose, then were tracheotomized, catheterized, and had the sciatic nerve exposed. Alexa Fluor 488 Isolectin GS‐IB4 conjugate [178.6 μm/ml] was used to label the endothelial cells of the vessel wall allowing for visualization of the epineurial vessels using intravital video microscopy. PE (10 −5 M) or NE (10 −5 M) was topically applied to the sciatic region for 4 minutes, separately. Images were obtained at baseline, immediately prior to drug application, and every minute for 4 minutes during application. Data are expressed at the time point that maximum change in diameter occurred. Data are expressed as mean ± standard error. Results Application of PE (n=11) resulted in a vasoconstriction (baseline: 22.0 ± 2.1 μm, PE: 19.3 ± 2.0 μm; P<0.05). Similarly, topical application of NE (n=8) induced a vasoconstriction (baseline: 31.2 ± 4.5 μm, NE: 26.5 ± 4.6 μm; P<0.05). Mean arteriolar pressure was unaffected during either PE (baseline: 99.1 ± 5.6 mmHg, PE: 97.4 ± 5.4 mmHg) or NE (baseline: 104.0 ± 4.5 mmHg, NE: 107.3 ± 7.7 mmHg) application. Conclusion Both PE and NE caused vasoconstriction at the sciatic nerve, which is consistent with previous studies in other tissues observing vasoconstriction through activation of α‐1 adrenergic receptors. As PE and NE are both α‐1 receptor agonists, these findings suggest that α‐1 receptors may be involved in blood flow regulation at the peripheral nerves. Support or Funding Information This study was supported by the SEED Research Grant from The University of Western Ontario. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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 | 0.000 | 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) | 0.001 | 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".