Evidence map›Paper›PMID 40397043›Full record

ArticlePsychopharmacology2026

Dose-extending placebo effect in a rat model of buprenorphine maintenance treatment.

Kayla M Pitts, Emma M Pilz, Luana Colloca, Yavin Shaham, Jonathan J Chow

Abstract read
In one paragraph

Article in Psychopharmacology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Kayla M PittsBehavioral Neuroscience Branch, Intramural Research Program, NIDA, NIH, Baltimore, MD, USA.
Emma M PilzBehavioral Neuroscience Branch, Intramural Research Program, NIDA, NIH, Baltimore, MD, USA.
Luana CollocaSchool of Nursing, University of Maryland, Baltimore, MD, USA.
Yavin ShahamBehavioral Neuroscience Branch, Intramural Research Program, NIDA, NIH, Baltimore, MD, USA. yavin.shaham@nih.gov.ORCID http://orcid.org/0000-0002-8242-3319
Jonathan J ChowBehavioral Neuroscience Branch, Intramural Research Program, NIDA, NIH, Baltimore, MD, USA. jonathan.chow@nih.gov.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

RATIONALE AND

objectiveClinical studies have shown that exposure to placebos or combining placebos with a lower medication dose can mimic the effect of a higher effective medication dose. This "dose-extending placebo effect" has been demonstrated in treatment for pain and other medical conditions but not in addiction. Here, we tested if a "dose-extending placebo effect" occurs in a rat model of opioid (buprenorphine) maintenance.

methodsWe trained 27 rats to self-administer remifentanil (5 µg/kg/infusion, 1-h per day). Next, we implanted some rats with buprenorphine minipumps (3 mg/kg/day, Exp. 1) or pretreated others with daily intravenous buprenorphine (0.3 mg/kg, Exp. 2), and introduced a discriminative cue (houselight + tone) during the self-administration sessions (the buprenorphine-maintenance cue). After discontinuing buprenorphine treatment, we retrained the rats for remifentanil self-administration without the cue. Next, we tested the effect of low and high buprenorphine doses (0.15 and 0.3 mg/kg), the buprenorphine-maintenance cue, and the combination of the low-dose with the cue on remifentanil self-administration.

resultsRats learned to self-administer remifentanil, and buprenorphine maintenance suppressed drug self-administration. The low buprenorphine dose modestly decreased self-administration, while the high dose caused a strong inhibition. Tests for the "dose-extending placebo effect" showed that discriminative buprenorphine cue alone had no effect, while the low dose plus the buprenorphine cue mimicked the inhibitory effect of the high dose.

conclusionsThis proof-of-concept study suggests that a "dose-extending placebo effect" can be modeled in rats undergoing opioid maintenance. This approach could support dose-reduction strategies in humans undergoing opioid maintenance therapy.

Indexed as

Analgesics, OpioidBuprenorphineOpiate Substitution TreatmentPlacebo EffectAnimalsCuesDose-Response Relationship, DrugMaleRatsRats, Sprague-DawleyRemifentanilSelf AdministrationAnalgesics, OpioidBuprenorphineRemifentanilBuprenorphineDrug self-administrationOpioid maintenance treatmentPlaceboRemifentanil

Identifiers

PMID40397043
PMCPMC13242476

What Socratic holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.