Functional Evidence for an Inward Rectifier Potassium Current in Rat Renal Afferent Arterioles
Bibliographic record
Abstract
An inward rectifier potassium current, Kir, has been identified in cerebral and coronary resistance vessels, where it is considered to be an important determinant of resting membrane potential (RMP) and to play a role in blood flow regulation. We investigated the functional role of Kir in the renal afferent arteriole using the in vitro-perfused hydronephrotic rat kidney. Increasing external KCl from 5 to 15 mmol/L induced afferent arteriolar vasodilation. This response was inhibited by 10 to 100 micromol/L Ba(2+), concentrations selective for blockade of Kir, and by chloroethylclonidine (100 micromol/L) but was not blocked by glibenclamide (10 micromol/L) or ouabain (3 mmol/L). Reducing external KCl from 5 to 1.5 mmol/L to enhance rectification of Kir caused vasoconstriction at low renal arterial pressure (40 mm Hg) and vasodilation during myogenic vasoconstriction (120 mm Hg), suggesting that this current dominates RMP at low perfusion pressures. When administered to kidneys perfused at 40 mm Hg renal arterial pressure, 30 micromol/L Ba(2+) elicited afferent arteriolar depolarization, reducing RMP from -47+/-2 to -34+/-2 mV (n=10, P:<0.0001), and vasoconstriction, reducing diameters from 14.5+/-1 to 10.9+/-0.8 microm (n=10, P:=0.0016). Although Ba(2+) reduced resting diameter, blockade of Kir did not prevent myogenic signaling in this vessel. Our findings thus demonstrate the presence of Kir in rat renal afferent arterioles and suggest that this current is an important determinant of RMP in situ.
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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 | 0.001 | 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".