Hemorrhage induced inactivation of presynaptic group III mGluRs controls metaplasticity in circuits regulating fluid balance
Bibliographic record
Abstract
In response to perturbations in body fluid homeostasis, noradrenaline (NA) is released in the paraventricular nucleus (PVN) of the hypothalamus to modulate neuroendocrine output. Here, we use whole‐cell patch clamp recordings from magnocellular neurosecretory cells in the PVN to show that bath application of NA (5 min, 100 μM) induces a robust, fast‐acting, long‐term depression (LTD) at glutamatergic synapses. This LTD is accompanied by a loss of presynaptic signaling at group III mGluRs. Depressed, but not naïve glutamatergic synapses exhibit a rapid presynaptic potentiation in response to high frequency stimulation. To determine if a physiological stressor that activates noradrenergic fibers to the PVN could induce similar changes in synaptic strength, slices were taken from rats that were hemorrhaged (under anesthesia, removal of 25% blood volume via cardiac puncture). In hemorrhaged rats, glutamatergic synapses displayed a reduced release probability and were unresponsive to the mGluR agonist, L‐AP4. High frequency stimulation of these synapses induced a rapid LTP. The ability of synapses to switch between depressed and potentiated states may be an important mechanism for filtering irrelevant activity (i.e. emotional inputs) from activity critical to controlling cardiovascular homeostasis. This work was supported by the 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".