Evidence map›Paper›PMID 33410983›Full record

ArticlePsychopharmacology2021

Temporal parameters of enhanced opioid reward after initial opioid exposure in rats.

Megan J Moerke, S Stevens Negus

Open access · greenAbstract read
In one paragraph

Article in Psychopharmacology, 2021. 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
0.4field-weighted citation impact, top 48% of its field
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, 4 citations in OpenAlex.

  1. Article
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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

2 authors at 2 institutions in 1 country.

Megan J MoerkeDepartment of Pharmacology and Toxicology, Virginia Commonwealth University, 410 N. 12th St., Richmond, VA, 23298, USA.ORCID http://orcid.org/0000-0002-5250-138X
S Stevens NegusDepartment of Pharmacology and Toxicology, Virginia Commonwealth University, 410 N. 12th St., Richmond, VA, 23298, USA. sidney.negus@vcuhealth.org.
National Institute on Drug Abuse · USVirginia Commonwealth University · US

Funding

TRAINING IN THE PHARMACOLOGY OF ABUSED DRUGST32DA007027 · NIDA · VIRGINIA COMMONWEALTH UNIVERSITY · PI William L. Dewey · 1985 to 2026
$14.7M
Neurobiology and Treatment of PainR01NS070715 · NINDS · VIRGINIA COMMONWEALTH UNIVERSITY · PI NEGUS, SIDNEY S, SELLEY, DANA E · 2009 to 2018
$3.3M
NIDA NIH HHS T32 DA007027NIH HHS R01NS070715NIH HHS T32DA007027NINDS NIH HHS R01 NS070715
6 · The paper itself

Abstract

rationaleMu opioid receptor agonists are indispensable for the treatment of pain, but clinical use carries the inherent risk of transition from effective treatment to abuse. Abuse potential appears to increase rapidly during periods of initial opioid exposure in humans, and this increase in opioid reward during initial opioid exposure can be modeled in rats using an intracranial self-stimulation (ICSS) procedure.

objectivesThe goal of the present study was to examine temporal parameters of this phenomenon.

methodsAdult male Sprague-Dawley rats responded for electrical brain stimulation using a frequency-rate ICSS procedure. In the first experiment, rats received daily morphine injections for 6 days, and morphine effects on ICSS were re-determined 1 day, 1 week, or 1 month after the repeated morphine treatment regimen to evaluate the persistence of enhanced opioid reward. In the second experiment, rats received six repeated morphine injections with different interdose intervals (two per day, one per day, every other day, every fourth day), and morphine effects were re-determined 1 day after the last dose to determine dosing frequencies sufficient to produce enhanced opioid reward.

resultsResults of the first experiment indicated that enhanced opioid reward was greatest 1 day after the morphine treatment regimen and completely dissipated after 4 weeks. The second experiment indicated that all dosing frequencies tested were sufficient to produce enhanced reward.

conclusionsTaken together, these results suggest that enhancement of opioid reward after initial opioid exposure is relatively transient but can be produced by a range of different dosing frequencies.

Indexed as

RewardAnalgesics, OpioidAnimalsBrainElectric StimulationMaleMorphinePainRatsRats, Sprague-DawleyReceptors, Opioid, muSelf StimulationTime FactorsAnalgesics, OpioidMorphineReceptors, Opioid, muAbuseIntracranial self-stimulationMorphineMu opioid receptor agonistTolerance

Identifiers

PMID33410983
PMCPMC7914195
OpenAlexW3119115064

What OpenQuestion holds

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Registered trials

None linked

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.