Hydrogen Sulfide Decreases Blood Pressure by Influencing the Excitability of Area Postrema Neurons
Bibliographic record
Abstract
Hydrogen sulfide (H 2 S), an endogenous gaseous transmitter, has been shown to act in the central nervous system (CNS) to influence cardiovascular (CV) function. Microinjection of H 2 S into central autonomic control centers such as the paraventricular nucleus and subfornical organ has been shown to increase blood pressure (BP) and electrophysiological studies have demonstrated that H 2 S depolarizes neurons in these same regions. Depolarizing effects of H 2 S have also been demonstrated in the nucleus tractus solitarius, a medullary autonomic control center with reciprocal connections to the immediately adjacent area postrema (AP). The AP is a circumventricular organ (CVO) with well documented roles in cardiovascular regulation. The present study was undertaken to examine the cardiovascular effects of microinjection of the H 2 S donor, sodium hydrogen sulfide (NaHS), into the AP of urethane anesthetized male Sprague Dawley rats and the cellular consequences of bath application of NaHS on the excitability of dissociated AP neurons. Microinjection (0.5 μl) of NaHS (10 μM) caused rapid, short duration (<90 sec) decreases in BP (mean area under the curve (AUC) =−389.2 ± 82.6 mmHg*sec, n=6) and HR (mean AUC = −6.6 ± 1.4 beats, n=6) while whole cell perforated patch electrophysiology revealed that bath application of NaHS (1mM) elicited solely hyperpolarizing responses (mean Δ in membrane potential = −3.6 ± 0.8 mV, n=8) in the majority (n=8/13) of AP neurons tested. These observations identify the AP as a CNS location at which H 2 S may act to influence cardiovascular regulation. Support or Funding Information Supported by Canadian Institutes of Health Research
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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".