Muscarinic receptor antagonism in the basolateral amygdala blocks acquisition of cocaine-stimulus association in a model of relapse to cocaine-seeking behavior in rats

Neuroscience. 2003;117(2):477-83. doi: 10.1016/s0306-4522(02)00665-6.

Abstract

Recent evidence has demonstrated a critical role for the basolateral amygdala complex in the reinstatement of extinguished drug-seeking behavior produced by drug-paired cues. In the current study, we utilized a model of the acquisition and expression of cocaine-stimulus associative pairing in order to study the role of cholinergic input to the basolateral amygdala in mediating conditioned-cued reinstatement. Male, Sprague-Dawley rats were first trained daily to self-administer i.v. cocaine on a fixed ratio 1 schedule of reinforcement. The muscarinic acetylcholine receptor antagonist, scopolamine, was directly infused into the basolateral amygdala prior to: a) classically conditioned pairing of a tone+light stimulus with cocaine infusions (acquisition), or b) testing of conditioned-cued reinstatement following a period of withdrawal from cocaine and extinction of cocaine-paired lever responding. Infusion of scopolamine just prior to the classical conditioning trial produced a dose-dependent disruption of cocaine-seeking behavior maintained by cocaine-paired cues during the reinstatement test. In contrast, infusion of scopolamine prior to the reinstatement test had no effect on conditioned-cued reinstatement of cocaine-seeking behavior. These results indicate a crucial role for cholinergic innervation of muscarinic acetylcholine receptors in the basolateral amygdala during the formation, but not the expression, of stimulus-reward associations that mediate cue-induced cocaine-seeking behavior.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amygdala / drug effects*
  • Animals
  • Behavior, Addictive / drug therapy*
  • Behavior, Addictive / psychology
  • Cocaine / administration & dosage*
  • Cocaine / antagonists & inhibitors
  • Dose-Response Relationship, Drug
  • Male
  • Muscarinic Antagonists / pharmacology
  • Muscarinic Antagonists / therapeutic use*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Muscarinic / physiology*
  • Secondary Prevention
  • Self Administration / psychology

Substances

  • Muscarinic Antagonists
  • Receptors, Muscarinic
  • Cocaine