Repeated administration of a dopamine D1 receptor agonist reverses the increased proportions of striatal dopamine D1<sup>High</sup> and D2<sup>High</sup> receptors in methamphetamine‐sensitized rats
Bibliographic record
Abstract
Repeated administration of psychostimulants produces a behavioural sensitization. Amphetamine-sensitized animals are known to have a higher proportion of high-affinity states of dopamine D2 receptors (D2(High) receptors) in the striatum. We recently reported that repeated administration of a dopamine D1 receptor agonist, R-(+)-SKF38393, reverses the established behavioural sensitization to methamphetamine (MAP). To investigate the mechanisms for reversal of behavioural sensitization, we examined the effect of repeated administration of the dopamine D1 receptor agonist on the proportions of D2(High) receptors and the high-affinity states of dopamine D1 receptors (D1(High) receptors) in the striatum. In the striatum from the MAP-sensitized rats, the proportions of D1(High) and D2(High) receptors (28.5 +/- 1.96 and 57.5 +/- 3.58%) were higher than those in the saline-control rats (12.0 +/- 1.01 and 21.9 +/- 1.60%, respectively). Repeated administration of R-(+)-SKF38393 to the MAP-sensitized rats reduced the increased proportions of D1(High) and D2(High) receptors to 12.4 +/- 1.57 and 31.0 +/- 2.14%, respectively, which were similar to the proportions in the saline-control rats. The total densities of dopamine D1 and D2 receptors were not altered in each treatment condition. The results demonstrate that the proportions of D1(High) and D2(High) receptors in the striatum are elevated in MAP-sensitized rats, and that repeated administration of the dopamine D1 receptor agonist to the MAP-sensitized rats reverses the increased proportions of D1(High) and D2(High) receptors. The findings reveal postsynaptic mechanisms for the development of behavioural sensitization to MAP and the reversal of established sensitization by repeated administration of the dopamine D1 receptor agonist.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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; 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".