Dopaminergic Enhancement of Excitatory Synaptic Transmission in Layer II of the Lateral Entorhinal Cortex
Bibliographic record
Abstract
Previous research demonstrated that dopamine produces concentration-dependent changes in synaptic transmission in the entorhinal cortex, wherein high concentrations of dopamine (50 µM) suppress evoked excitatory postsynaptic potentials (EPSPs) and lower concentrations of dopamine (1 to 10 µM) facilitate them. Whole-cell current clamp recordings were used to investigate the dopaminergic facilitation of synaptic responses in layer II neurons of the lateral entorhinal cortex. Surprisingly, the pattern of changes in EPSPs was dependent on cell type. During bath applications of 1 µM dopamine, fan cells showed a facilitation of the amplitude of EPSPs evoked by layer I stimulation. In contrast, pyramidal cells showed mixed modulation of EPSPs in response to dopamine, with different cells showing either facilitation or suppression effects. Voltage clamp recordings of excitatory postsynaptic currents suggest that dopamine facilitates AMPA glutamate receptor-mediated EPSCs. To determine the dopaminegic receptor subtype involved, either the D1 receptor blocker SCH23390 (50 µM) or the D2 receptor blocker sulpiride (50 µM) was bath applied to the slices prior to dopamine. Application of SCH 23390 blocked the facilitation of EPSCs, whereas application of sulpiride had no significant effect. Therefore, the dopaminergic enhancement of EPSCs is likely to be mediated primarily through D1-like receptors. D1 receptors can act through a variety of intracellular signaling pathways to modulate synaptic strength. The role of signaling via protein kinase A was tested by including the PKA inhibitor H-89 in the recording pipette solution. Cells filled with H-89 did not show a facilitation of EPSCs in response to dopamine application. Thus, the dopamine-induced facilitation of AMPA receptor-mediated synaptic responses in the lateral entorhinal cortex appears to be mediated via a D1 receptor-dependent increase in PKA activity.
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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".