Estrogen pretreatment modulates morphine-induced conditioned place preference in ovariectomized mice.
Pharmacol Biochem Behav
; 92(3): 399-403, 2009 May.
Article
em En
| MEDLINE
| ID: mdl-19463255
ABSTRACT
Estrogen is known to modulate the neurotransmission in the brain. The main aim of this study was to investigate the effects of estrogen on the rewarding properties of morphine using conditioned place preference (CPP) paradigm in adult female mice. The possible rewarding effect of estrogen was also examined in ovariectomized mice. Following a 6-day conditioning procedure, sham operated animals showed a significant preference towards the side previously paired with a range of morphine doses (2, 5 and 10--but not 20--mg/kg, SC). However, ovariectomized mice showed decreased CPP compared to gonadally intact mice with a right shift in their morphine dose-response curve. These effects were reversed by chronic daily administration of estradiol benzoate (EB; 20 microg/kg, SC). Furthermore, in ovariectomized mice, EB per se was able to induce CPP. In conclusion, our findings indicate that estradiol has a facilitating effect on morphine reward while its deficiency increases the threshold dose of morphine to induce CPP.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ovariectomia
/
Condicionamento Clássico
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Estrogênios
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Morfina
Limite:
Animals
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article