Context-specific increase of glutamate transmission in cocaine-conditioned place preference: an in vivo microdialysis study

EULIARTE PIA; GUZMAN ANDREA SUSANA; AVALOS MARIA PAULA; SANCHEZ MARIANELA ADELA; OLIVEROS LEANDRO; RIGONI DAIANA; BOLLATI FLAVIA; CANCELA LILIANA M

Cordoba

Congreso; 2018 Meeting of Argentine Society for Research in Neurosciences; 2018

Sociedad Argentina de Neurociencias

The conditioned place preference (CPP) paradigm results suitable to evaluate the neurobiological changes induced bya cocaine-associated context in absence of the drug.Specifically, pharmacological evidence from our laboratorydemonstrated the role of glutamatergic transmissionwithin the nucleus accumbens (NAc) in different phases ofcocaine-CPP. The aim of the present study was to evaluate invivo changes in extracellular glutamate (GLU) levels in NAcas a result of cocaine conditioning and extinction. For this, amicrodialysis assay was performed in male Wistar ratstrained to acquire and then to extinguish cocaine-inducedCPP. Animals were stereotaxically implanted with microdialysisprobes, and then GLU dialysate samples were collectedin the experimental room, first in the home cage to determinebasal levels and then in the cocaine-paired or in theunpaired context. Dialysate samples were quantified byHPLC coupled with electrochemical detection. Results indicatethat the enhancement of GLU is specific for thecocaine-paired context since animals evaluated before conditioningor in the unpaired context did not show suchincrease during re-exposure to the context. Furthermore,the increase of GLU was not either observed followingextinction of cocaine-CPP. These findings support the ideathat pairing cocaine with a specific context can modulateglutamate transmission in NAc influencing cocaine-seekingbehavior and this can disappear after extinction of drug-CPP.