Voltage-activated Ca2+ channels in rat renal afferent and efferent myocytes: no evidence for the T-type Ca2+ current
Bibliographic record
Abstract
AIMS: Based on indirect methods, it has been suggested that both L- and T-type Ca(2+) channels mediate signalling in the renal afferent arteriole and that T-type Ca(2+) channels are involved in signalling in the efferent arteriole. However, Ca(2+) currents have never been studied in these two vessels. Our study was initiated to directly determine the type of Ca(2+) channels in these vessels for the first time, using patch clamp. METHODS AND RESULTS: Native myocytes were obtained from individually isolated rat renal afferent and efferent arterioles and from rat tail arteries (TA). TA myocytes, which possess both L- and T-type Ca(2+) currents, served as a positive control. Inward Ca(2+) and Ba(2+) currents (I(Ca) and I(Ba)) were measured in 1.5 mmol/L Ca(2+) and 10 mmol/L Ba(2+), respectively, using the whole-cell configuration. By exploiting known differences in activation and inactivation characteristics and differing sensitivities to nifedipine and kurtoxin, the presence of both L- and T-type Ca(2+) channels in TA myocytes was readily demonstrated. Afferent arteriolar myocytes exhibited relatively large I(Ca) densities (-2.0 ± 0.2 pA/pF) in physiological Ca(2+) and the I(Ba) was 3.6-fold greater. These currents were blocked by nifedipine, but not by kurtoxin, and did not exhibit the activation and inactivation characteristics of T-type Ca(2+) channels. Efferent arteriolar myocytes did not exhibit a discernible voltage-activated I(Ca) in physiological Ca(2+). CONCLUSION: Our findings support the physiological role of L-type Ca(2+) channels in the afferent, but not efferent, arteriole, but do not support the premise that functional T-type Ca(2+) channels are present in either vessel.
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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 | 0.003 | 0.001 |
| 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".