Effect of acute ethanol administration on the extracellular concentrations of the opioid peptides [beta]-endorphin, met-enkephalin and dynorphin Aâ-â at the level of ventral tegmental area in the rat
Bibliographic record
Abstract
There is experimental evidence suggesting that ethanol alters the activity of the endogenous opioid peptide systems in a dose and brain region dependent manner. These ethanol-induced alterations in opioid activity may influence the processes of ethanol reward and reinforcement. However, the precise nature of the link between ethanol-opioid interactions influencing reward and reinforcement is not clearly understood. Thus, it was the objective of the present study to investigate the response of the three major opioid peptide systems (endorphins, enkephalins, and dynorphins) to acute ethanol administration, at the level of the ventral tegmental area (VTA), a brain region important for drug, including ethanol, reinforcement. Using the in vivo microdialysis technique coupled with specific solid-phase radioimmunoassays for beta-endorphin, met-enkephalin, and dynorphin A1-8, changes of the extracellular concentration of theses peptides at the level of VTA were determined at distinct time points following the administration of 0.0 (saline), 0.8, 1.6, and 2.4 g ethanol/kg B/Wt. Results demonstrated a biphasic effect of ethanol on beta-endorphin release with 1.6, but not 0.8 or 2.4, g ethanol/kg B.Wt. enhancing beta-endorphin release. None of the ethanol doses used altered the extracellular levels of met-enkephalin, and dynorphin A1-8 peptides. In conclusion, the present findings suggest that at the level of VTA interactions of beta-endorphin with the mu and/or delta opioid receptors on GABA interneurons may contribute to the ethanol induced augmentation in the activity of the mesolimbic dopaminergic system, and influence ethanol reinforcement.
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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) | 0.002 | 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".