Angiotensin II Induces Calcium-Dependent Rhythmic Activity in a Subpopulation of Rat Hypothalamic Median Preoptic Nucleus Neurons
Bibliographic record
Abstract
Whole cell patch-clamp recordings revealed a subpopulation (16%, n = 18/112) of rat median preoptic nucleus (MnPO) neurons responded to bath-applied angiotensin II (Ang II; 100 nM to 5 microM; 30-90 s) with a prolonged TTX-resistant membrane depolarization and rhythmic bursting activity. At rest, cells characteristically displayed relatively low input resistance and negative resting potentials. Ang-II-induced responses featured increased input resistance, a reversal potential of -95 +/- 2 mV, an increase in action potential duration from 2.9 +/- 0.5 to 4.3 +/- 0.8 ms, and the appearance of a rebound excitation at the offset of membrane responses to hyperpolarizing current injection. The latter was sensitive to Ni2+ (0.5-1 mM; n = 5), insensitive to extracellular Cs+ (1 mM, n = 7), and intracellular QX-314 (4 mM, n = 5), consistent with activation of a T-type Ca2+ conductance. Coincident with the Ang-II-induced depolarization was the appearance of rhythmic depolarizing shifts at a frequency of 0.14 +/- 0.09 Hz with superimposed bursts of 4-22 action potentials interspersed with silent periods persisting for >1 h after washout. These TTX-resistant depolarizing shifts increased in amplitude and decreased in frequency with membrane hyperpolarization with activity ceasing beyond approximately -80 mV, and were abolished in low-Ca(2+)/high-Mg2+ bathing medium (n = 6), Co2+ (1 mM; n = 6), or Ni2+ (0.5-1 mM; n = 8). Thus in a subpopulation of MnPO neurons, Ang II induces "pacemaker-like" activity by reducing a K(+)-dependent leak conductance that contributes to resting membrane potential and promoting of Ca(2+)-dependent regenerative auto-excitation mediated, in part, by a T-type Ca2+ conductance.
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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 | 0.000 |
| 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 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".