Dissociation of physical abstinence signs from changes in extracellular dopamine in the nucleus accumbens and in the prefrontal cortex of nicotine dependent rats.
Drug Alcohol Depend
; 58(1-2): 93-102, 2000 Feb 01.
Article
en En
| MEDLINE
| ID: mdl-10669059
ABSTRACT
The aim of the present study was to investigate the relationship between physical abstinence and changes in dopamine release in the nucleus accumbens and in the medial prefrontal cortex induced by mecamylamine and naloxone in rats chronically exposed to nicotine. The rats were implanted with osmotic minipumps (Alzet) delivering nicotine tartrate at a rate of 9 mg/kg/day (3.16 mg of free base) and 8 days later with a dialysis probe in the nucleus accumbens or in the medial prefrontal cortex. Steady-state dopamine output from the nucleus accumbens of the rats implanted with nicotine minipumps was higher than that of sham implanted rats; no differences were observed in the prefrontal cortex. In nicotine but not in sham implanted rats mecamylamine (1 mg/kg s.c.) precipitated a physical abstinence syndrome and brought dopamine output back to control values in the nucleus accumbens. In contrast mecamylamine (1 mg/kg s.c.) increased dopamine output in the medial prefrontal cortex of nicotine but not sham-implanted rats. Naloxone (2 mg/kg) precipitated a physical abstinence syndrome qualitatively similar to that produced by mecamylamine but failed to modify extracellular dopamine in the nucleus accumbens or in the prefrontal cortex of nicotine-implanted and sham-implanted rats. The results indicate that the mesolimbic and mesocortical dopamine system undergo opposite changes during mecamylamine-precipitated abstinence in rats chronically exposed to nicotine and that physical abstinence signs can be dissociated from changes in dopamine transmission.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Síndrome de Abstinencia a Sustancias
/
Dopamina
/
Corteza Prefrontal
/
Nicotina
/
Núcleo Accumbens
Tipo de estudio:
Diagnostic_studies
/
Etiology_studies
Límite:
Animals
Idioma:
En
Revista:
Drug Alcohol Depend
Año:
2000
Tipo del documento:
Article
País de afiliación:
Italia