K <sup>+</sup> efflux through postsynaptic <scp>NMDA</scp> receptors suppresses local astrocytic glutamate uptake
Bibliographic record
Abstract
Abstract Glutamatergic transmission prompts K + efflux through postsynaptic NMDA receptors. The ensuing hotspot of extracellular K + elevation depolarizes presynaptic terminal, boosting glutamate release, but whether this also affects glutamate uptake in local astroglia has remained an intriguing question. Here, we find that the pharmacological blockade, or conditional knockout, of postsynaptic NMDA receptors suppresses use‐dependent increase in the amplitude and duration of the astrocytic glutamate transporter current (I GluT ), whereas blocking astrocytic K + channels prevents the duration increase only. Glutamate spot‐uncaging reveals that astrocyte depolarization, rather than extracellular K + rises per se, is required to reduce the amplitude and duration of I GluT . Biophysical simulations confirm that local transient elevations of extracellular K + can inhibit local glutamate uptake in fine astrocytic processes. Optical glutamate sensor imaging and a two‐pathway test relate postsynaptic K + efflux to enhanced extrasynaptic glutamate signaling. Thus, repetitive glutamatergic transmission triggers a feedback loop in which postsynaptic K + efflux can transiently facilitate presynaptic release while reducing local glutamate uptake.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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; both teacher heads agree on what is shown here.
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".