Dopamine D1 or D2 receptor antagonism within the basolateral amygdala differentially alters the acquisition of cocaine-cue associations necessary for cue-induced reinstatement of cocaine-seeking

Neuroscience. 2006;137(2):699-706. doi: 10.1016/j.neuroscience.2005.08.064. Epub 2005 Nov 14.

Abstract

The basolateral amygdala complex has been implicated in the formation and utilization of cocaine-cue associations in rat models of cue-induced reinstatement to cocaine-seeking behavior. We have previously demonstrated the importance of dopamine inputs to the basolateral amygdala complex in the reinstatement of cocaine-seeking behavior following chronic cocaine self-administration. Here we show that selective blockade of amygdalar dopamine D1 and D2 receptors during acquisition of cocaine-cue associations has distinctive effects on subsequent conditioned-cued cocaine-seeking behavior. Male, Sprague-Dawley rats were first trained to self-administer i.v. cocaine on a fixed ratio 1 schedule for 5 days. Subjects then received bilateral, intra-basolateral amygdala complex infusions of a dopamine D1 receptor antagonist (SCH23390, 0.25-2.0 microg/side; experiment 1), a dopamine D2 receptor antagonist (raclopride, 0.625-5.0 microg/side; experiment 2), or vehicle just prior to a single classical conditioning session, during which a light+tone cue was discretely paired with passive infusions of cocaine in the absence of lever responding. Following five additional days of cocaine self-administration and 7-10 days of extinction training, animals underwent multiple tests for cue-induced reinstatement. SCH23390 (2.0 microg/side), administered at the time of cocaine-cue association only, produced an attenuation of reinstatement to cue-induced cocaine-seeking behavior. In contrast, low doses of raclopride potentiated, while a higher dose of raclopride attenuated cue-induced reinstatement. These results demonstrate unique contributions of D1 vs. D2 receptors in mediating dopamine inputs within the basolateral amygdala complex during the formation of cocaine-stimulus associations that are critical for cue-induced reinstatement.

Publication types

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

MeSH terms

  • Amygdala / drug effects*
  • Amygdala / metabolism
  • Amygdala / physiopathology
  • Animals
  • Association*
  • Cocaine / pharmacology*
  • Cocaine-Related Disorders / metabolism*
  • Cocaine-Related Disorders / physiopathology
  • Conditioning, Psychological / drug effects
  • Conditioning, Psychological / physiology
  • Cues
  • Disease Models, Animal
  • Dopamine Antagonists / pharmacology
  • Dopamine Uptake Inhibitors / pharmacology
  • Dose-Response Relationship, Drug
  • Extinction, Psychological / drug effects
  • Extinction, Psychological / physiology
  • Male
  • Neurons / drug effects*
  • Neurons / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine / drug effects*
  • Receptors, Dopamine / metabolism
  • Receptors, Dopamine D1 / drug effects
  • Receptors, Dopamine D1 / metabolism
  • Receptors, Dopamine D2 / drug effects
  • Receptors, Dopamine D2 / metabolism
  • Reinforcement, Psychology
  • Secondary Prevention
  • Self Administration

Substances

  • Dopamine Antagonists
  • Dopamine Uptake Inhibitors
  • Receptors, Dopamine
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2
  • Cocaine