title: The NMDA antagonist MK-801 disrupts reconsolidation of a cocaine-associated memory for conditioned place preference but not for self-administration in rats.
abstract: Recent research suggests that drug-related memories are reactivated after exposure to environmental cues and may undergo reconsolidation, a process that can strengthen memories. Conversely, reconsolidation may be disrupted by certain pharmacological agents such that the drug-associated memory is weakened. Several studies have demonstrated disruption of memory reconsolidation using a drug-induced conditioned place preference (CPP) task, but no studies have explored whether cocaine-associated memories can be similarly disrupted in cocaine self-administering animals after a cocaine priming injection, which powerfully reinstates drug-seeking behavior. Here we used cocaine-induced CPP and cocaine self-administration to investigate whether the N-methyl-D-aspartate receptor antagonist (+)-5methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801) given just prior to reactivation sessions would suppress subsequent cocaine-primed reinstatement (disruption of reconsolidation). Systemic injection of MK-801 (0.05 or 0.20 mg/kg administered intraperitoneally) in rats just prior to reactivation of the cocaine-associated memory in the CPP context attenuated subsequent cocaine-primed reinstatement, while no disruption occurred in rats that did not receive reactivation in the CPP context. However, in rats trained to self-administer cocaine, systemic administration of MK-801 just prior to either of two different types of reactivation sessions had no effect on subsequent cocaine-primed reinstatement of lever-pressing behavior. Thus, systemic administration of MK-801 disrupted the reconsolidation of a cocaine-associated memory for CPP but not for self-administration. These findings suggest that cocaine-CPP and self-administration do not use similar neurochemical processes to disrupt reconsolidation or that cocaine-associated memories in self-administering rats do not undergo reconsolidation, as assessed by lever-pressing behavior under cocaine reinstatement conditions.
authors.affiliation: Alcohol and Drug Abuse Research Program and Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington 99164-6520, USA.
authors.forename: Travis E
authors.initials: TE
authors.lastname: Brown
authors.forename: Brian R
authors.initials: BR
authors.lastname: Lee
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Sorg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016739:Behavior, Addictive / Q000503:physiopathology / Q000523:psychology; D003042:Cocaine / Q000008:administration & dosage*; D003216:Conditioning, Operant / Q000187:drug effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000008:administration & dosage*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005108:Extinction, Psychological / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D012646:Self Administration
chemical_list: D018765:Dopamine Uptake Inhibitors; D018691:Excitatory Amino Acid Antagonists; D010879:Piperazines; D016291:Dizocilpine Maleate; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid; D003042:Cocaine