Regional Specificity in the Real-Time Development of Phasic Dopamine Transmission Patterns During Acquisition of a Cue-Cocaine Association in Rats

Eur J Neurosci. 2009 Nov;30(10):1889-99. doi: 10.1111/j.1460-9568.2009.07027.x. Epub 2009 Nov 11.

Abstract

Drug seeking is significantly regulated by drug-associated cues and associative learning between environmental cues and cocaine reward is mediated by dopamine transmission within the nucleus accumbens (NAc). However, dopamine transmission during early acquisition of a cue-cocaine association has never been assessed because of the technical difficulties associated with resolving cue-evoked and cocaine-evoked dopamine release within the same conditioning trial. Here, we used fast-scan cyclic voltammetry to measure sub-second fluctuations in dopamine concentration within the NAc core and shell during the initial acquisition of a cue-cocaine Pavlovian association. Within the NAc core, cue-evoked dopamine release developed during conditioning. However, within the NAc shell, the predictive cue appeared to cause an unconditioned decrease in dopamine concentration. The pharmacological effects of cocaine also differed between sub-regions, as cocaine increased phasic dopamine release events within the NAc shell but not the core. Thus, real-time measurements not only revealed the initial development of a conditioned neurochemical response but also demonstrated differential phasic dopamine transmission patterns across NAc sub-regions during the acquisition of a cue-cocaine association.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Animals
  • Behavior, Animal
  • Cocaine / administration & dosage*
  • Cocaine / pharmacology
  • Conditioning, Classical / physiology*
  • Cues*
  • Dopamine / metabolism*
  • Dopamine Uptake Inhibitors / administration & dosage*
  • Dopamine Uptake Inhibitors / pharmacology
  • Male
  • Nucleus Accumbens / cytology
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / physiology
  • Probability
  • Rats
  • Rats, Sprague-Dawley
  • Self Administration
  • Sucrose / administration & dosage
  • Sucrose / pharmacology
  • Sweetening Agents / administration & dosage
  • Sweetening Agents / pharmacology
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology*
  • Time Factors

Substances

  • Dopamine Uptake Inhibitors
  • Sweetening Agents
  • Sucrose
  • Cocaine
  • Dopamine