Kappa-opioid receptor modulation of accumbal dopamine concentration during operant ethanol self-administration.
Neuropharmacology
; 51(3): 487-96, 2006 Sep.
Article
em En
| MEDLINE
| ID: mdl-16781738
ABSTRACT
Our study examined ethanol self-administration and accumbal dopamine concentration during kappa-opioid receptor (KOPr) blockade. Long-Evans rats were trained to respond for 20 min of access to 10% ethanol (with sucrose) over 7 days. Rats were injected s.c. with the long-acting KOPr antagonist, nor-binaltorphimine (NOR-BNI; 0 or 20 mg/kg) 15-20 h prior to testing. Microdialysis revealed a transient elevation in dopamine concentration within 5 min of ethanol access in controls. NOR-BNI-treated rats did not exhibit this response, but showed a latent increase in dopamine concentration at the end of the access period. The rise in dopamine levels correlated positively with dialysate ethanol concentration but not in controls. NOR-BNI did not alter dopamine levels in rats self-administering 10% sucrose. The transient dopamine response during ethanol acquisition in controls is consistent with previous results that were attributed to ethanol stimulus cues. The altered dopamine response to NOR-BNI during ethanol drinking suggests that KOPr blockade temporarily uncovered a pharmacological stimulation of dopamine release by ethanol. Despite these neurochemical changes, NOR-BNI did not alter operant responding or ethanol intake, suggesting that the KOPr is not involved in ethanol-reinforced behavior under the limited conditions we studied.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Dopamina
/
Depressores do Sistema Nervoso Central
/
Receptores Opioides kappa
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Condicionamento Operante
/
Etanol
/
Núcleo Accumbens
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Neuropharmacology
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Estados Unidos