Evidence map›Paper›PMID 39333403›Full record

ArticlePsychopharmacology2024

Comparison of the reinforcing, antinociceptive, and respiratory depressant effects of prototypical and G-protein biased mu-opioid receptor agonists in male and female Sprague-Dawley rats.

C Austin Zamarripa, Tanya Pareek, Loc M Pham, Bruce E Blough, Hayley M Schrock, Eric J Vallender, Kenneth J Sufka, Kevin B Freeman

Abstract readComparative Study
In one paragraph

Article in Psychopharmacology, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
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

2 citing papers in PubMed.

  1. Elucidating biased signaling in class A GPCRs.Trends in pharmacological sciences · 2025
    Review
  2. Article
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

8 authors.

C Austin ZamarripaDepartment of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA. czamarr2@jhmi.edu.ORCID http://orcid.org/0000-0002-6426-8984
Tanya PareekDepartment of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.ORCID http://orcid.org/0000-0001-9133-0811
Loc M PhamDepartment of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
Bruce E BloughSchool of Pharmacy, Research Triangle Park, NC, USA.
Hayley M SchrockDepartment of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
Eric J VallenderDepartment of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
Kenneth J SufkaDepartment of Psychology, University of Mississippi, Oxford, MS, USA.
Kevin B FreemanDepartment of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.

Funding

Deterrents for prescription opioid abuseR01DA039167 · NIDA · UNIVERSITY OF MISSISSIPPI MED CTR · PI FREEMAN, KEVIN B. · 2015 to 2025
$4.9M
Therapeutic selectivity of biased mu-opioid agonists.F31DA048586 · NIDA · UNIVERSITY OF MISSISSIPPI MED CTR · PI ZAMARRIPA, CARLOS AUSTIN · 2019 to 2021
$82k
NIDA NIH HHS F31 DA048586NIDA NIH HHS F31-DA048586NIDA NIH HHS R01 DA039167NIDA NIH HHS R01-DA039167
6 · The paper itself

Abstract

rationaleG-protein biased mu-opioid receptor (MOR) agonists have been reported to exhibit superior therapeutic windows compared to prototypical MOR agonists when relating antinociception to respiratory depression. However, there is relatively little research on the abuse potential of G-protein biased MOR agonists in relation to other behavioral endpoints.

objectivesThe aim of the present study was to quantitatively compare the reinforcing, antinociceptive, and respiratory-depressant effects of the prototypical MOR agonists, fentanyl and oxycodone, to the G-protein biased MOR agonists, SR14968 and SR17018, in male and female rats.

methodsIn the self-administration study, four separate groups of Sprague-Dawley (SD) rats self-administered intravenous (i.v.) fentanyl, oxycodone, SR14968, and SR17018 under a progressive-ratio schedule of reinforcement. Using a within-subjects design, separate cohorts of SD rats were tested with i.v. fentanyl, oxycodone, SR14968, and SR17018 using a hot-plate assay, assays of neuropathic and inflammatory antinociception, and whole-body plethysmography.

resultsAll MOR agonists functioned as reinforcers, but SR14968 and SR17018 were less efficacious relative to oxycodone and fentanyl. Moreover, all MOR agonists produced dose-dependent and fully efficacious antinociception across all nociception modalities. Oxycodone and fentanyl, but not SR14968 or SR17018, produced respiratory depression in a dose-dependent manner.

conclusionThe present results indicate that the G-protein biased MOR agonists tested herein produce MOR-typical antinociception, exhibit reduced but apparent abuse potential, and do not produce respiratory effects at doses that are above the antinociceptive range. Atypical MOR agonists within the SR series should be further studied as foundational molecules for the development of safter analgesics.

Indexed as

Analgesics, OpioidFentanylOxycodoneRats, Sprague-DawleyReceptors, Opioid, muSelf AdministrationAnimalsDose-Response Relationship, DrugFemaleMaleRatsReinforcement, PsychologyReinforcement ScheduleRespiratory InsufficiencySpiro CompoundsThiophenes((3-methoxythiophen-2-yl)methyl)((2-(9-(pyridin-2-yl)-6-oxaspiro(4.5)decan-9-yl)ethyl))amineAnalgesics, OpioidFentanylOxycodoneReceptors, Opioid, muSpiro CompoundsThiophenesAntinociceptionFentanylOxycodoneRespiratory depressionSelf-administrationSR14968SR17018

Identifiers

PMID39333403
PMCPMC13273602

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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 OpenQuestion graph.