The Journal of Neuroscience, 2001, 21:RC141:1-4
RAPID COMMUNICATION
Cocaine and Amphetamine Increase Extracellular Dopamine in
the Nucleus Accumbens of Mice Lacking the Dopamine Transporter
Gene
Ezio
Carboni1,
Cécile
Spielewoy2,
Cinzia
Vacca1,
Marika
Nosten-Bertrand2,
Bruno
Giros2, and
Gaetano
Di
Chiara1
1 Department of Toxicology and Consiglio Nazionale
delle Ricerche Center for Neuropharmacology, University of
Cagliari, 09126 Cagliari, Italy, and 2 Neurobiology and
Psychiatry Faculté de Medicine de Creteil, 94000 Creteil, France
Behavioral and biochemical studies suggest that dopamine (DA) plays
a role in the reinforcing and addictive properties of drugs of abuse.
Recently, this hypothesis has been challenged on the basis of the
observation that, in mice genetically lacking the plasma membrane
dopamine transporter [DAT-knock out (DAT-KO)], cocaine maintained its
reinforcing properties of being self-administered and inducing place
preference, despite the failure to increase extracellular dopamine in
the dorsal striatum. Here we report that, in DAT-KO mice, cocaine and
amphetamine increase dialysate dopamine in the medial part of the
nucleus accumbens. Moreover, reboxetine, a specific blocker of the
noradrenaline transporter, increased DA in the nucleus accumbens of
DAT-KO but not of wild-type mice; in contrast, GBR 12909, a specific
blocker of the dopamine transporter, increased dialysate dopamine in
the nucleus accumbens of wild-type but not of DAT-KO mice. These
observations provide an explanation for the persistence of cocaine
reinforcement in DAT-KO mice and support the hypothesis of a primary
role of nucleus accumbens dopamine in drug reinforcement.
Key words:
dopamine; nucleus accumbens; DAT-knock-out mice; cocaine; amphetamine; reboxetine
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