No Role of ATP-Sensitive Potassium Channels in the Vasoconstriction Produced by Vasopressin
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The contribution of ATP-sensitive potassium channel (K<sub>ATP</sub> channel) blockade in the vasoconstriction produced by vasopressin was studied. All experiments were performed using rat thoracic aorta cut in 4-mm rings, denuded from their endothelium and mounted into 20-ml organ baths. Glibenclamide (0.01–10 µM), a K<sub>ATP</sub> channel antagonist, did not induce any measurable contraction, nor did it reduce the maximum contraction induced by vasopressin and phenylephrine. The specific inhibition of lemakalim-induced (a K<sub>ATP</sub> channel activator) relaxation by vasopressin was investigated. Lemakalim (0.01–0.3 µM) relaxed both vasopressin (0.1 µM) and phenylephrine (0.3 µM) preconstricted vessels. However, in contrast to what would be expected from K<sub>ATP</sub> blockade by vasopressin, rings preconstricted with vasopressin were more sensitive to the relaxant action of lemakalim, compared to phenylephrine preconstricted vessels (log[EC<sub>50</sub>] of –7.82 ± 0.01 and –7.10 ± 0.02, respectively, p < 0.05). Dose-response curves to papaverine (3–30 µM) in rings preconstricted with vasopressin and phenylephrine were comparable. When aortic rings were pretreated with lemakalim (0.1 µM), the maximum active tension induced by vasopressin was reduced (2.68 ± 0.23 in control conditions vs. 0.62 ± 0.08 g on pretreated vessels, p < 0.001), whereas that by phenylephrine was slightly increased. In order to explain the stronger relaxant action of lemakalim against vasopressin-induced constriction, the contribution of calcium influx through L-type calcium channels in the constriction of aortic rings to vasopressin and phenylephrine was compared. Nifedipine (0.1 nM–30 µM) was more potent (lower EC50 and higher maximal response) in vasopressin (0.1 µM) preconstricted vessels, compared to phenylephrine (0.3 µM). In conclusion, vasoconstriction produced by vasopressin does not involve blockade of K<sub>ATP</sub> channels in the isolated rat aorta. The more potent relaxant action of lemakalim in vasopressin preconstricted vessels, compared to phenylephrine, can be explained by a higher dependency of vasopressin-induced vasoconstriction on calcium influx through voltage-sensitive calcium channels and, consequently, membrane potential.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 it