Localization and Characterization of Binding Sites for Circulating and Cerebroventricular Atrial Natriuretic Factor in Rat Choroid Plexus
Bibliographic record
Abstract
In vitro autoradiographic studies showed that high-affinity atrial natriuretic factor (ANF) binding sites are present on rat choroid plexus (Kd = 83.8 pM, Bmax = 22.9 fmol/mg protein). Guanylate cyclase-coupled receptors (ANF-R1) represent 30% and non-guanylate cyclase-coupled ANF receptors (ANF-R2) represent 70% of the total ANF receptors present in this tissue. To provide detailed cellular localization of the binding sites, the technique of electron-microscopic autoradiography was applied using 125I-ANF (Ser 99-Tyr 126) as an in vivo ligand. In order to identify possible binding sites at the basolateral and the apical aspects of the choroid plexus, the ligand was injected into the carotid artery or into the lateral cerebral ventricles, respectively. Light-microscopic autoradiography demonstrated that ANF binds specifically to choroid plexus regardless of its route of administration. Electron-microscopic autoradiography showed that silver grains were localized primarily on epithelial cells of the choroid plexus (96-99%) and marginally on endothelial and pial cells. In choroidal epithelial cells, ultrastructural analysis of silver grain distribution revealed that, at 2 min after intracarotid or intracerebroventricular 125I-ANF injection, lysosomes were the most distinctly labeled organelle (highest relative specific radioactivity). HPLC Chromatographic analysis disclosed that 96-99% of choroid plexus-bound ANF was already degraded 2 min after injection and that at least 63-66% of the degradation took place at the plasma membrane. These results indicate that ANF binding sites are present on both aspects of choroidal epithelium, and suggest that ANF is very quickly degraded in choroid plexus by membrane-associated as well as lysosome-associated processes.
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.
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".