Effect of steady-state methadone on high fructose corn syrup consumption in rats
Bibliographic record
Abstract
Patients undergoing methadone maintenance treatment self-report enhanced preferences for, and excessive consumption of, foods rich in sugar. However, it is unclear whether these are direct pharmacological effects of methadone or the consequences of metabolic dysfunctions induced by addiction to illicit opiates. Hence, the current study in drug-naïve male Sprague-Dawley rats explored the effects of steady-state methadone delivered by osmotic mini-pumps (13 days; 0, 10, 30 mg/kg/day) on consumption of rat chow and a palatable, sweet, liquid high fructose corn syrup solution. Six days after the removal of the pumps, mRNA expression of genes involved in responses to stress and rewards were quantified: pro-opiomelanocortin in the hypothalamus, mu-opioid receptor in the nucleus accumbens, and dopamine D2 receptor in the dorsal striatum. Taste reactivity and locomotion tests were also performed throughout the study. It was found that methadone increased caloric intake from high fructose corn syrup and reduced caloric intake from chow, effects that could not be directly ascribed to changes in high fructose corn syrup taste reactivity or motor functions. However, the changes in caloric intake displayed significant tolerance, and mRNA expression analysis suggested that methadone attenuated the effect of high fructose corn syrup on pro-opiomelanocortin mRNA, and possibly on dopamine D2 receptor mRNA. These findings in rats suggest that the pharmacological effect of methadone, administered to achieve steady-state maintenance, may not be the primary cause of dietary alterations reported by patients maintained on methadone.
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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) | 0.001 | 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 | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".