Psychopharmacology

, Volume 220, Issue 3, pp 619–625

Galanin negatively modulates opiate withdrawal via galanin receptor 1

  • Fiona E. Holmes
  • Athena Armenaki
  • Tiina P. Iismaa
  • Emily B. Einstein
  • John Shine
  • Marina R. Picciotto
  • David Wynick
  • Venetia Zachariou
Original Investigation

DOI: 10.1007/s00213-011-2515-x

Cite this article as:
Holmes, F.E., Armenaki, A., Iismaa, T.P. et al. Psychopharmacology (2012) 220: 619. doi:10.1007/s00213-011-2515-x

Abstract

Rationale

The neuropeptide galanin has been shown to modulate opiate dependence and withdrawal. These effects could be mediated via activation of one or more of the three distinct G protein-coupled receptors, namely galanin receptors 1 (GalR1), 2 (GalR2), and 3 (GalR3).

Objectives

In this study, we used several transgenic mouse lines to further define the mechanisms underlying the role played by galanin and its receptors in the modulation of morphine dependence. First, transgenic mice expressing β-galactosidase under the control of the galanin promoter were used to assess the regulation of galanin expression in response to chronic morphine administration and withdrawal. Next, the behavioral responses to chronic morphine administration and withdrawal were tested in mice that over-express galanin, lack the GalR1 gene, or lack the GalR2 gene.

Methods

Transgenic and matched wild-type mice were given increasing doses of morphine followed by precipitation of withdrawal by naloxone and behavioral responses to withdrawal were assessed.

Results

Both morphine administration and withdrawal increased galanin gene transcription in the locus coeruleus (LC). Increasing galanin levels in the brain reduced signs of opiate withdrawal. Mice lacking GalR1 undergo more severe opiate withdrawal, whereas mice lacking GalR2 show no significant difference in withdrawal signs, compare with matched wild-type controls.

Conclusions

Opiate administration and withdrawal increase galanin expression in the LC. Galanin opposes the actions of morphine which leads to opiate dependence and withdrawal, an effect that is mediated via GalR1.

Keywords

GalaninGalanin receptor 1MouseOpiateAddictionWithdrawalLocus coeruleus

Abbreviations

LacZ

β-Galactosidase

GalR1

Galanin receptor 1

GalR2

Galanin receptor 2

GalR3

Galanin receptor 3

LC

Locus coeruleus

WT

Wild type

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Fiona E. Holmes
    • 1
  • Athena Armenaki
    • 2
  • Tiina P. Iismaa
    • 3
  • Emily B. Einstein
    • 4
  • John Shine
    • 3
  • Marina R. Picciotto
    • 4
  • David Wynick
    • 1
  • Venetia Zachariou
    • 2
  1. 1.Schools of Physiology and Pharmacology and Clinical SciencesUniversity of BristolBristolUK
  2. 2.Department of PharmacologyFaculty of Medicine, University of CreteHeraklionGreece
  3. 3.Neuroscience ProgramGarvan Institute of Medical ResearchSydneyAustralia
  4. 4.Department of PsychiatryYale University School of MedicineNew HavenUSA