Intra-medial prefrontal cortex injections of scopolamine increase instrumental responses for cocaine: an intravenous self-administration study in rats.
Brain Res Bull
; 51(2): 151-8, 2000 Jan 15.
Article
em En
| MEDLINE
| ID: mdl-10709961
ABSTRACT
The present experiments examined the effects of muscarinic cholinergic receptor blockade in the nucleus accumbens (NAC) and medial prefrontal cortex (MPC) on intravenous cocaine self-administration. Adult male Sprague-Dawley rats were implanted with chronic indwelling jugular catheters and guide cannulae stereotaxically aimed at the NAC or MPC. The rats were then given the opportunity to intravenously self-administer cocaine (0.8 mg/kg/infusion) during daily 2-h sessions. Intra-NAC microinjections of methyl-scopolamine (2, 4, 8, 16, and 32 microg/side) or vehicle did not affect either the number of lever presses made or infusions delivered. On the other hand, intra-MPC injections of scopolamine significantly increased responding, although there was only a trend for an increase in the number of cocaine infusions. The effects of intra-MPC injections of scopolamine (8 and 16 microg/side) on locomotor activity were also evaluated. Intra-MPC injections of scopolamine (16 microg/side) produced significant increases in locomotor activity. However, these same microinjections decreased locomotor activity when the animals also received cocaine (15 mg/kg, i.p.). These results suggest that cholinergic neurotransmission at muscarinic receptors in the MPC is involved in regulating cocaine-maintained responding.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escopolamina
/
Córtex Pré-Frontal
/
Cocaína
/
Antagonistas Muscarínicos
Limite:
Animals
Idioma:
En
Revista:
Brain Res Bull
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Estados Unidos