Effects of opioid blockade on the modulation of pain and mood by sweet taste and blood pressure in young adults
Bibliographic record
Abstract
Increased blood pressure and sweet taste are often associated with decreased pain sensitivity. Animal research suggests that endogenous opioids are involved in both these relationships. Fifty-eight healthy young adults (36 male, 22 female) participated in two sessions receiving a placebo tablet or 50mg of naltrexone on counterbalanced days. On each day, three cold-pressor tests were administered while the participant held a sweet solution, water, or nothing in their mouth when their hand was in the water. 2 Drug x 3 Solution x 2 Gender x Pre-Drug Resting Blood Pressure general linear models (GLM) were conducted separately for systolic (SBP) and diastolic (DBP) pressure. Consistent with previous research, significant main effects of SBP were observed in GLMs of pain tolerance and pain unpleasantness ratings. A main effect of solution on tolerance was seen in the GLM with DBP, which was qualified by an interaction of solution by blood pressure. Sweet taste increased pain tolerance among those with lower DBP across drug conditions. This suggests some overlap between mechanisms of sweet taste and blood pressure analgesia, without implicating opioid activity in sweet taste analgesia. However, the GLM of tolerance also produced a significant drug by DBP interaction suggesting that blood pressure-related analgesia is at least partially opioid-mediated. Also participants with higher DBP showed dampened mood reactivity to the experiment, which was partially reversible by naltrexone. These results are consistent with findings suggesting that endogenous opioid activity may contribute to generally reduced pain sensitivity, and perhaps mood reactivity, in those with higher BP.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".