title: Rapid induction of dopamine sensitization in the nucleus accumbens shell induced by a single injection of cocaine.
abstract: Repeated intermittent exposure to cocaine results in the neurochemical sensitization of dopamine (DA) transmission within the nucleus accumbens (NAc). Indeed, the excitability of DA neurons in the ventral tegmental area (VTA) is enhanced within hours of initial psychostimulant exposure. However, it is not known if this is accompanied by a comparably rapid change in the ability of cocaine to increase extracellular DA concentrations in the ventral striatum. To address this question we used fast-scan cyclic voltammetry (FSCV) in awake-behaving rats to measure DA responses in the NAc shell following an initial intravenous cocaine injection, and then again 2-h later. Both injections quickly elevated DA levels in the NAc shell, but the second cocaine infusion produced a greater effect than the first, indicating sensitization. This suggests that a single injection of cocaine induces sensitization-related plasticity very rapidly within the mesolimbic DA system.
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA. Electronic address: bfsinger@umich.edu.
authors.forename: Bryan F
authors.initials: BF
authors.lastname: Singer
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA.
authors.forename: Myranda A
authors.initials: MA
authors.lastname: Bryan
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA.
authors.forename: Pavlo
authors.initials: P
authors.lastname: Popov
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA.
authors.forename: Terry E
authors.initials: TE
authors.lastname: Robinson
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, 530 Church Street, East Hall, Ann Arbor, MI 48109, USA.
authors.forename: Brandon J
authors.initials: BJ
authors.lastname: Aragona
mesh_terms: D000818:Animals; D003042:Cocaine / Q000008:administration & dosage*; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D017207:Rats, Sprague-Dawley; D017557:Ventral Tegmental Area / Q000187:drug effects* / Q000502:physiology
chemical_list: D003042:Cocaine; D004298:Dopamine
keywords: Cocaine; Dopamine; Nucleus accumbens; Psychostimulant; Sensitization; Voltammetry