Origins of heart rate variability: autonomic blockade of large magnitude, transient bradycardia in conscious rabbits.
Bibliographic record
Abstract
BACKGROUND: Heart period sequences are composed of recurrent, similarly shaped, physiologically meaningful, transient heart period structures. One such structure is a large magnitude transient bradycardia (LMTB), which resembles published reports of responses to alerting stimuli. Alerting responses are sensitive to alpha1-adrenoceptor and cholinergic receptor blockade. OBJECTIVES: To determine whether LMTBs are related to alerting responses by assessing the response of rabbit LMTBs to autonomic inhibitors. ANIMALS AND METHODS: Using a Latin square, crossover design, six conscious, unsedated rabbits received placebo, intramuscular glycopyrrolate 0.05 mg/kg and intravenous prazosin 0.15 mg/kg, and six rabbits received placebo, intravenous metoprolol 0.15 mg/kg and intravenous ICI-118,551 0.1 mg/kg. Heart period and blood pressure were continuously recorded, digitized and analyzed off-line. RESULTS: LMTBs were suppressed by 93% and 95% by alpha1-adrenergic and muscarinic blockade, respectively, but not by beta1-adrenergic or beta2-adrenergic blockade. The drugs altered none of the morphological parameters of shape, magnitude or duration, or any of the hypotensive features. CONCLUSIONS: LMTBs are similar to alerting responses; they are both expressed as transient hypotensive and bradycardic events that are markedly reduced by muscarinic and alpha1-adrenoceptor blockade but not by beta-adrenoceptor blockade. The presence of LMTBs may indicate ongoing, subtle changes in the laboratory environment.
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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 | 0.001 |
| 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".