Myogenic Constriction is not Dependent on Endothelium in Arcuate and Mesenteric Arteries of Normotensive and Hypertensive Rats
Bibliographic record
Abstract
Background Myogenic response (MR) is defined as contraction of small arteries in response to increased intraluminal pressure. Impaired MR is associated with hypertension and Chronic Kidney Disease (CKD). MR has been shown to be regulated by endothelium (ENDO) through production of vasodilators and vasoconstrictors which are differentially produced in different vascular beds. Despite this evidence, there are conflicting literature reports on the dependency of MR on ENDO. This dependency was never investigated in arcuate and mesenteric arteries of normotensive and hypertensive rats. We hypothesized that MR is dependent on ENDO and removing ENDO abolishes MR in arcuate and mesenteric arteries of Wistar Kyoto (WKY, normotensive) and Spontaneously Hypertensive Rats (SHR, hypertensive) rats. Methods Arteries were mounted in a pressure myograph chamber (PMC) filled with oxygenated Hank Balance Salt Solution (HBSS) to create a blind sac and allowed 30 min to equilibrate. Intact vascular smooth muscle cell (VSMC) and ENDO layers were evaluated by addition of a pre‐determined median effective dose of phenylephrine (0.2 μM) and carbachol (10 μM) respectively. MR was measured in response to step‐wise increases in intraluminal pressure from 80 to 180 mmHg (20 mmHg increments, 5 min each) (E‐intact MR). The arteries were then transferred into a petri dish containing human hair and moved through the length of the hair 5 times to remove ENDO (Osol et al., 1989). The vessels were re‐mounted, HBSS was flushed through the arteries for 5 mins, and blind sac was re‐created. Phenylephrine and carbachol were added and MR was re‐measured (E‐removed MR). Physical absence of ENDO was further assessed by Scanning Electron Microscopy (SEM). Results All arteries contracted to phenylephrine before and after ENDO removal and did not relax significantly to carbachol after ENDO removal. SEM micrographs showed complete physical absence of the ENDO. MC in E‐removed vessels were not significantly different from MC in E‐intact in mesenteric and arcuate arteries of WKY and SHR rats. Conclusions Our study validated an ENDO removal method that was described by Osol, et al . in 1989. Additionally, MR was shown to be independent of ENDO in mesenteric and arcuate arteries of WKY and SHR rats. Support or Funding Information This work was supported by Canadian Institutes of Health Research grants to Dr. Jeffrey G. Dickhout (PJT148499). This abstract is from the Experimental Biology 2019 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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".