Dopamine enhances motor and neuropathological consequences of polyglutamine expanded huntingtin
Bibliographic record
Abstract
An expansion in the CAG repeat of the IT15 (huntingtin) gene underlies the development of Huntington's disease (HD), but the basis for the specific vulnerability of dopamine-receptive striatal neurons remains unclear. To examine the potential role of the dopamine system in the emergence of pathological conditions in HD, we generated a double mutant mouse strain with both enhanced dopamine transmission and endogenous expression of a mutant huntingtin gene. This strain was generated by crossing the dopamine transporter knock-out mouse, which exhibits a 5-fold elevation in extracellular dopamine levels in the striatum and locomotor hyperactivity, to a knock-in mouse model of HD containing 92 CAG repeats. These double mutant mice exhibited an increased stereotypic activity at 6 months of age, followed by a progressive decline of their locomotor hyperactivity. Expression of the mutated huntingtin did not alter dopamine or its metabolite levels in normal or dopamine transporter knock-out mice. However, the mutant huntingtin protein aggregated much earlier and to a greater extent in the striatum and other dopaminergic brain regions in the hyperdopaminergic mouse model of HD. Furthermore, the formation of neuropil aggregates in the striatum and other regions of hyperdopaminergic HD mice was observed at 4 months of age, well before similar events occurred in normal HD mice (12 months). These findings indicate that dopamine contributes to the deleterious effects of mutated huntingtin on striatal function, and this is accompanied by enhanced formation of huntingtin aggregates.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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 teacher head, 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".