Extracellular signal-regulated kinase in the basolateral amygdala, but not the nucleus accumbens core, is critical for context-response-cocaine memory reconsolidation in rats

Neuropsychopharmacology. 2013 Apr;38(5):753-62. doi: 10.1038/npp.2012.238. Epub 2012 Nov 21.

Abstract

The reconsolidation of cocaine memories following retrieval is necessary for the sustained ability of a cocaine-paired environmental context to elicit cocaine seeking. Extracellular signal-regulated kinase (ERK) is an intracellular signaling molecule involved in nucleus accumbens core (NACc)-mediated reconsolidation of Pavlovian cocaine memories. Here, we used a rodent model of drug context-elicited relapse to test the hypothesis that ERK would be similarly required for the reconsolidation of context-response-cocaine memories that underlie drug context-induced reinstatement of instrumental cocaine-seeking behavior, with a focus on the NACc and on the basolateral amygdala (BLA), another important locus for the reconsolidation of cocaine memories. We show that the mitogen-activated protein kinase (MEK)/ERK1/2 inhibitor, U0126 (1.0 μg/0.5 μl/hemisphere), microinfused bilaterally into the BLA--but not the NACc--immediately after brief re-exposure to a previously cocaine-paired context (that is, cocaine-memory reactivation), significantly attenuated subsequent drug context-induced cocaine seeking relative to vehicle (VEH). This effect in the BLA was associated with a transient inhibition of ERK1/2 phosphorylation, and it depended on memory reactivation given that U0126 administered following exposure to a novel context did not alter subsequent cocaine seeking. Furthermore, similar to U0126, baclofen+muscimol-induced (B+M; 106.8/5.7 ng/0.5 μl/hemisphere) neural inactivation of the NACc, following cocaine-memory reactivation, failed to alter subsequent cocaine seeking. These findings demonstrate that ERK activation in the BLA, but not the NACc, is required for the reconsolidation of context-response-cocaine associative memories. Together with prior research, these results suggest that contextual drug-memory reconsolidation in Pavlovian and instrumental settings involves distinct neuroanatomical mechanisms.

Publication types

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

MeSH terms

  • Amygdala / drug effects
  • Amygdala / enzymology
  • Animals
  • Baclofen / pharmacology
  • Butadienes / pharmacology
  • Cocaine / administration & dosage*
  • Cocaine-Related Disorders / enzymology
  • Cocaine-Related Disorders / pathology
  • Conditioning, Operant / drug effects
  • Conditioning, Operant / physiology*
  • Dopamine Uptake Inhibitors / administration & dosage*
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Extinction, Psychological / drug effects
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • GABA-B Receptor Agonists / pharmacology
  • Male
  • Memory / drug effects
  • Memory / physiology*
  • Muscimol / pharmacology
  • Nitriles / pharmacology
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / enzymology*
  • Rats
  • Rats, Sprague-Dawley
  • Reinforcement Schedule
  • Self Administration
  • Signal Transduction / drug effects

Substances

  • Butadienes
  • Dopamine Uptake Inhibitors
  • Enzyme Inhibitors
  • GABA-B Receptor Agonists
  • Nitriles
  • U 0126
  • Muscimol
  • Extracellular Signal-Regulated MAP Kinases
  • Baclofen
  • Cocaine