Context-specific increase of extracellular glutamate in nucleus accumbens: a role in stress-induced reinstatement of cocaine-conditioned place preference

EULIARTE PIA V; BOLLATI F; AVALOS M.P; RIGONI D; CANCELA L.M; GUZMAN A.S; SANCHEZ M.A; VIRGOLINI M

SANTIAGO DE COMPOSTELA

Congreso; 18th National Meeting of the Spanish Society of Neuroscience (SENC 2019); 2019

Spanish Society of Neuroscience (SENC 2019)

CONTEXT-SPECIFIC INCREASE OFEXTRACELLULAR GLUTAMATE IN NUCLEUS ACCUMBENS: A ROLE IN STRESS-INDUCEDREINSTATEMENT OF COCAINE-CONDITIONED PLACE PREFERENCE A. S. Guzman, M. P. Avalos, P. V. Euliarte, M. A.Sanchez, L. A. Oliveros, J. Boezio, D. Rigoni, L. N. De Giovanni; F. A.Bollati, M. B. Virgolini, L. M. Cancela.Facultad de Ciencias Químicas, Universidad Nacionalde Córdoba, Córdoba, Argentina.  Exposure to a drug-paired context or stressors areconsidered the most important triggers that induce relapse in human addicts andin animal models of drug addiction, but the neurobiology of the interactionbetween these two factors to promote reinstatement has been scarcely studied.In this sense, pharmacological evidence from our lab support the critical roleof the glutamatergic transmission within the nucleus accumbens (NAc) instress-induced reinstatement of cocaine- conditioned place preference (CPP).The aim of the present study was to design a time course experiment in order tomonitor in vivo transient changes in extracellular glutamate (GLU) levelswithin NAc in response to a re-exposure to the drug-paired compartment of theCPP apparatus after conditioning, extinction and stress-induced reinstatementof cocaine-CPP. In vivo microdialysis experiment in male Wistar rats, combinedwith high-performance liquid chromatography and electrochemical detection wasused. On one hand, our results demonstrated that in vivo changes inextracellular GLU levels within NAc are related to the increased or thediminished preference for the drug-paired chamber after conditioning andextinction of cocaine-CPP, respectively. Moreover, results demonstrated thecompartment-specific increase in extracellular levels of GLU within NAc inanimals submitted to restraint stress after extinction of cocaine-CPP, sincethe ?unpaired group? and ?no stress group? did not show such GLU enhancement.The present study uniquely indicates that under the cocaine-CPP paradigm, it isplausible to demonstrate the concurrent context-dependent potentiation ofbehavioral and in vivo glutamatergic responses in absence of the drug occurringin conjunction with the restraint stress influence. This provides neurochemicalbasis to investigate mechanisms underpinning the influence of drug-relatedcontext in stress-induced reinstatement.