Evidence map›Paper›PMID 32422213›Full record

ReviewNeuropharmacology2020

Endogenous opioid peptides in the descending pain modulatory circuit.

Elena E Bagley, Susan L Ingram

Registry-linked trialOpen access · greenAbstract readReview
PubMed Full text at PMC Publisher
In one paragraph

Review in Neuropharmacology, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06666621 (Antagonism of Endogenous Opioids), which is not on this map. Cited by 101 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
101citing papers in PubMed, 1 pooled it
9.2field-weighted citation impact, top 1% 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.

NCT06666621 phase4recruitingnot on this mapstarted 2024, after this paper: background citation

Antagonism of Endogenous Opioids: Use in Interpretation of Injections

TypeinterventionalSponsorMiddle Tennessee Research InstituteRan2024 to 2026Enrolled33ConditionsLow Back Pain, Zygapophyseal Joint ArthritisArmsNormal saline infusion, Naloxone infusion
3 · Its place in the literature

Who cites it

101 citing papers in PubMed, 1 synthesis or guideline pooled it, 164 citations in OpenAlex.

  1. Pooled it
  2. Trial
  3. Trial
  4. Trial
  5. Review
  6. Article
  7. Article
  8. Article
  9. Dorsal raphe nucleus enkephalin peptide modulates behavioral preference.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2026
    Article
  10. Article
  11. Review
  12. Review
  13. Article
  14. Review
  15. Endogenous mediators in regulating primary dysmenorrhea.Frontiers in cell and developmental biology · 2026
    Review
  16. Review
  17. Cannabinoid CB1 receptor and mu-opioid receptor interaction: new insights from conditional knockout mice.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2026
    Article
  18. Review
  19. Review
  20. PET Imaging of the Human Brain with Microvolumetric Spatial Resolution.Journal of nuclear medicine : official publication, Society of Nuclear Medicine · 2025
    Article

41 more citing papers are in PubMed but not listed here.

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 2 countries.

Elena E BagleyDiscipline of Pharmacology and Charles Perkins Centre, University of Sydney, NSW, 2006, Australia.
Susan L IngramDepartment of Neurological Surgery, Oregon Health & Science University, Portland, OR, 97239, USA. Electronic address: ingrams@ohsu.edu.
Oregon Health & Science University · USUniversity of Sydney · AU

Funding

Cannabinoid and opioid modulation of descending pain circuits in chronic painR01DA042565 · NIDA · OREGON HEALTH & SCIENCE UNIVERSITY · PI HEINRICHER, MARY MAGDALEN, INGRAM, SUSAN L · 2017 to 2021
$2.0M
NIDA NIH HHS R01 DA042565
6 · The paper itself

Abstract

The opioid epidemic has led to a serious examination of the use of opioids for the treatment of pain. Opioid drugs are effective due to the expression of opioid receptors throughout the body. These receptors respond to endogenous opioid peptides that are expressed as polypeptide hormones that are processed by proteolytic cleavage. Endogenous opioids are expressed throughout the peripheral and central nervous system and regulate many different neuronal circuits and functions. One of the key functions of endogenous opioid peptides is to modulate our responses to pain. This review will focus on the descending pain modulatory circuit which consists of the ventrolateral periaqueductal gray (PAG) projections to the rostral ventromedial medulla (RVM). RVM projections modulate incoming nociceptive afferents at the level of the spinal cord. Stimulation within either the PAG or RVM results in analgesia and this circuit has been studied in detail in terms of the actions of exogenous opioids, such as morphine and fentanyl. Further emphasis on understanding the complex regulation of endogenous opioids will help to make rational decisions with regard to the use of opioids for pain. We also include a discussion of the actions of endogenous opioids in the amygdala, an upstream brain structure that has reciprocal connections to the PAG that contribute to the brain's response to pain.

Indexed as

AmygdalaAnimalsHumansOpioid PeptidesPainPain ManagementPain PerceptionPeriaqueductal GrayReceptors, OpioidOpioid PeptidesReceptors, OpioidAmygdalaBeta-endorphinEnkephalinOpioidPainPeriaqueductal grayRostral ventromedial medulla

Identifiers

PMID32422213
PMCPMC7313723
OpenAlexW3024279011

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

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.