Muscarinic Suppression of Excitatory Synaptic Responses in Layer II of the \nEntorhinal Cortex
Bibliographic record
Abstract
The entorhinal cortex is thought to play a role in mechanisms mediating sensory and mnemonic function, but the effects of acetylcholine on the strength of sensory cortical inputs to the entorhinal cortex are not well understood.We have previously shown that field excitatory postsynaptic potentials (fEPSPs) in the medial entorhinal cortex evoked by stimulation of the piriform cortex are suppressed during theta activity in behaving animals, and that cholinergic agonism suppresses fEPSPs in vivo.In addition, intracellular recordings from neurons in layer II of the entorhinal cortex also show a suppression of EPSPs in response to the cholinergic agonist carbachol.Here, we have used in vitro field potential recordings evoked by stimulation of layer I afferents to investigate the transmitter receptors that mediate the cholinergic suppression of synaptic responses in layer II of the medial entorhinal cortex.Ten-min bath-application of the cholinergic agonist carbachol (10 µM) potently suppressed the amplitude of fEPSPs.Carbachol also enhanced the paired-pulse facilitation ratio for EPSP amplitudes (30 ms interpulse interval), indicating that the cholinergic suppression is likely due to inhibition of transmitter release.Constant bath application of the M 2 receptor blocker methoctramine (5 µM) for 20 min prior to addition of carbachol did not prevent the cholinergic suppression, but application of the M 1 receptor blocker pirenzepine (1 µM) almost completely blocked the carbachol-induced suppression, indicating that the cholinergic suppression of excitatory synaptic responses in the entorhinal cortex is iv dependent primarily on activation of M 1 -like receptors.In addition to enhancements in neuronal excitability that follow cholinergic activation, therefore, cells in the superficial layers of the entorhinal cortex also display a suppression of excitatory synaptic input that is mediated mainly by M 1 muscarinic receptors.v ACKNOWLEDGEMENTS First and foremost, this project would not have been possible without the assistance and encouragement from Dr. C. Andrew Chapman.I would like to
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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) | 0.001 | 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".