Expression of amphetamine sensitization is associated with recruitment of a reactive neuronal population in the nucleus accumbens core.
Psychopharmacology (Berl)
; 198(1): 113-26, 2008 May.
Article
in En
| MEDLINE
| ID: mdl-18347780
ABSTRACT
RATIONALE Repeated exposure to psychostimulant drugs causes a long-lasting increase in the psychomotor and reinforcing effects of these drugs and an array of neuroadaptations. One such alteration is a hypersensitivity of striatal activity such that a low dose of amphetamine in sensitized animals produces dorsal striatal activation patterns similar to acute treatment with a high dose of amphetamine. OBJECTIVES:
To extend previous findings of striatal hypersensitivity with behavioral observations and with cellular activity in the nucleus accumbens and prefrontal cortex in sensitized animals. MATERIALS ANDMETHODS:
Rats treated acutely with 0, 1, 2.5, or 5 mg/kg i.p. amphetamine and sensitized rats challenged with 1 mg/kg i.p. amphetamine were scored for stereotypy, rearing, and grooming, and locomotor activity recorded. c-fos positive nuclei were quantified in the nucleus accumbens and prefrontal cortex after expression of sensitization with 1 mg/kg i.p. amphetamine.RESULTS:
Intense stereotypy was seen in animals treated acutely with 5 mg/kg amphetamine, but not in the sensitized group treated with 1 mg/kg amphetamine. The c-fos response to amphetamine in the accumbens core was augmented in amphetamine-pretreated animals with a shift in the distribution of optical density, while no effect of sensitization was seen in the nucleus accumbens shell or prefrontal cortex.CONCLUSIONS:
A lack of stereotypy in the sensitized group indicates a dissociation of behavioral responses to amphetamine and striatal immediate-early gene activation patterns. The increase in c-fos positive nuclei and shift in the distribution of optical density observed in the nucleus accumbens core suggests recruitment of a new population of neurons during expression of sensitization.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Recruitment, Neurophysiological
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Amphetamine
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Central Nervous System Stimulants
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Neurons
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Nucleus Accumbens
Type of study:
Risk_factors_studies
Limits:
Animals
Language:
En
Journal:
Psychopharmacology (Berl)
Year:
2008
Document type:
Article
Affiliation country:
Netherlands
Country of publication:
ALEMANHA
/
ALEMANIA
/
DE
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DEUSTCHLAND
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GERMANY