Galanin protects against behavioral and neurochemical correlates of opiate reward.
Neuropsychopharmacology
; 33(8): 1864-73, 2008 Jul.
Article
de En
| MEDLINE
| ID: mdl-17957220
ABSTRACT
The mechanisms underlying responses to drugs of abuse have been widely investigated; however, less is known about pathways normally protective against the development of drug reinforcement. These pathways are also important since they may regulate individual differences in vulnerability to addiction. The neuropeptide galanin and its binding sites are expressed in brain areas important for drug reward. Previous studies have shown that centrally infused galanin attenuates morphine place preference and peripheral injection of galnon, a galanin agonist, decreases opiate withdrawal signs. The current studies in galanin knockout (GKO) mice examined the hypothesis that galanin is an endogenous negative regulator of opiate reward and identified downstream signaling pathways regulated by galanin. We show that GKO mice demonstrate increased locomotor activation following morphine administration, which is inhibited by acute administration of galnon. GKO mice also show enhanced morphine place preference, supporting the idea that galanin normally antagonizes opiate reward. In addition, morphine-induced ERK1/2 phosphorylation was increased in the VTA of both wild-type and GKO mice, but only the GKO mice showed increases in ERK1/2 and CREB phosphorylation in the amygdala or nucleus accumbens. Furthermore, a single systemic injection of galnon in GKO mice was sufficient to reverse some of the biochemical changes brought about by morphine administration. These data suggest that galanin normally attenuates behavioral and neurochemical effects of opiates; thus, galanin agonists may represent a new class of therapeutic targets for opiate addiction.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Récompense
/
Comportement animal
/
Chimie du cerveau
/
Galanine
/
Dépendance à la morphine
Limites:
Animals
Langue:
En
Journal:
Neuropsychopharmacology
Sujet du journal:
NEUROLOGIA
/
PSICOFARMACOLOGIA
Année:
2008
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique