Orexin-A Depolarizes Dissociated Rat Area Postrema Neurons through Activation of a Nonselective Cationic Conductance
Bibliographic record
Abstract
The area postrema (AP) is involved in the regulation of body fluid balance, feeding behavior, and cardiovascular function. Orexin (ORX)-A is a 33 aa peptide that regulates energy metabolism and sympathetic and cardiovascular actions. ORX immunoreactive axons and their varicose terminals have been found in AP. In this study, whole-cell, current- or voltage-clamp recordings were obtained from 108 dissociated rat AP neurons. The mean resting membrane potential of these neurons (n = 48) was -59.24 +/- 0.87 mV, the mean input resistance was 3.57 +/- 0.22 G(Omega), and the action potential amplitude of these cells was always >90 mV. Current-clamp studies showed bath application of ORX-A depolarized the majority of AP neurons tested (68.8%; 33 of 48), whereas small proportions of cells were either hyperpolarized (16.7%; 8 of 48) or unaffected (14.6%; 7 of 48). These depolarizing effects were found to be concentration dependent from 10(-8) to 10(-11) m. We then examined the contributions of specific ionic conductances to the ORX-A-induced excitation of AP neurons through whole-cell, voltage-clamp studies. Our results demonstrate that in contrast to previous studies on other neuronal populations, ORX-A did not affect net whole-cell potassium currents in AP neurons. Slow depolarizing voltage ramps, however, revealed that ORX-A enhanced a nonselective cationic conductance in AP neurons, effects which would explain the depolarizing effects of the peptide. These data demonstrate that AP neurons are directly influenced by ORX-A and suggest that ORX-A may exert its effects on the central control of feeding behavior and cardiovascular function through direct actions in AP.
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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".