Astrocytes from Cerebral Cortex or Striatum Attract Adult Host Serotoninergic Axons into Intrastriatal Ventral Mesencephalic Co-Grafts
Bibliographic record
Abstract
The identification of axon growth inhibitory molecules offers new hopes for repair of the injured CNS. However, the navigational ability of adult CNS axons and the guidance cues they can recognize are still essentially unknown. Astrocytes may express guidance molecules and are known to have different regional phenotypes. To evaluate their influence on the affinity of adult serotoninergic (5-HT) axons for a projection target, we co-implanted astrocytes from the neonatal striatum, cortex, or ventral mesencephalon together with fetal ventral mesencephalic tissue into the striatum of adult rats. Two months after surgery, quantification after in vitro 5-[1,2-(3)H]serotonin ([(3)H]5-HT) uptake and autoradiography showed that ventral mesencephalic grafts with co-grafted cortical or striatal astrocytes were four times and three times, respectively, more densely innervated by host 5-HT axons than control ventral mesencephalic grafts with or without co-grafted ventral mesencephalic astrocytes. Immunohistochemistry for glial fibrillary acidic protein, vimentin, or chondroitin-sulfate proteoglycans revealed no qualitative or quantitative differences in host astroglial scar or production of inhibitory molecules that could explain these differences in 5-HT innervation. These results demonstrate that astrocytes grown in culture from different brain regions have the potential to influence the growth and maintenance of adult 5-HT axons in a graft of neural tissue from another brain region. It should now be feasible to identify the molecules expressed by cultured cortical or striatal, but not by ventral mesencephalic, astrocytes that have these tropic actions on 5-HT axons of the neostriatum.
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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) | 0.001 | 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 | 0.001 |
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; 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".