Comparison of the Effect of Amiloride and Its Analogue Dichlorobenzamil on Cardiac Chronotropic Responses to Ouabain in Myocardial Cell Aggregates in Culture
Bibliographic record
Abstract
The purpose of this study was to compare the effects of amiloride, an inhibitor of Na(+)-H+ exchange, and its analog 3',4'-dichlorobenzamil, a more specific inhibitor of Na(+)-Ca2+ exchange on the response of cardiac myocytes to ouabain. Cardiac myocyte aggregates were prepared from myocytes obtained from 7-day-old chick embryo hearts. Ouabain at 10(-6) M produced a marked and significant (p less than 0.05) reduction in contractile frequency. Amiloride, at 10(-7) to 10(-5) M produced a definite, significant (p less than 0.05) and dose-dependent reduction in this effect of ouabain. In contrast, dichlorobenzamil, 10(-7) to 10(-6) M, significantly (p less than 0.05) accentuated this effect of ouabain. Thus, amiloride and its analog dichlorobenzamil have different effects on the cardiac responses to ouabain presumably because of the differences in the specificity of their inhibition of Na+/H+ and Na+/Ca2+ exchange. Thus to the extent that the effects of amiloride and dichlorobenzamil are mediated through, respectively Na(+)-H+ and Na(+)-Ca2+ exchange, these data suggest that ouabain-induced reduction in contractile frequency is mediated through Na(+)-H+ exchange while Na(+)-Ca2+ exchange acts to minimize this action of ouabain. Amiloride may be useful to oppose the negative chronotropic effect of ouabain while dichlorobenzamil accentuates this effect of ouabain.
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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 | 0.000 | 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 | 0.000 |
| 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".