Participation of G Proteins in Natriuretic Peptide Hormone Secretion from Heart Atria
Bibliographic record
Abstract
The involvement of G proteins in the mechanism underlying the increased atrial natriuretic factor (ANF) secretion observed after atrial muscle stretch (stretch-secretion coupling) was assessed using a combined pharmacological, immunocytochemical, and tissue fractionation approach. It was found that G(i/o) inhibition by pertussis toxin (PTX) abolished stretch-secretion coupling without affecting baseline secretion through a mechanism that is independent of G(q) signaling agonists. Mastoparan-7, a G(i/o) agonist, significantly increased ANF secretion even in the absence of muscle stretch through a PTX-sensitive mechanism. By confocal and electron immunocytochemistry, ANF and G(o) partially colocalized, whereas ultracentrifugation analysis suggested the presence of two populations of granules, one of which was partially associated with G(o), as demonstrated by Western blotting. PTX did not affect basal or endothelin-1-stimulated ANF secretion, in line with the view that endothelin-1 signals mainly through G(q). It is concluded there are at least two types of regulated secretory processes in atrial cardiocytes: one is acutely responsive to muscle stretch and is PTX sensitive, and the other is G(q)mediated and PTX insensitive and may be responsible for changes in secretion after chronic changes in the neuroendocrine environment.
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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".