Restraint Stress-Induced Enhancement of Glutamate Transmission Within Nucleus Accumbens Core After Extinction of Cocaine-Conditioned Place Preference: An In Vivo Microdialysis Study

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

Córdoba

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

Sociedad Argentina de Neurociencias

Stress is considered an important factor that induces relapsein human addicts and in animal models of addiction. Findingsfrom our lab demonstrated pharmacologically the role ofglutamatergic transmission within core, and not shell, subcompartmentof nucleus accumbens (NAc) in restraintstress-induced reinstatement of extinguished cocaine-conditionedplace preference (CPP). The present in vivo microdialysisstudy aims to evaluate the effect of a single restraintstress session on extracellular levels of glutamate (GLU) inNAc Core during a re-exposure to the drug-paired contextafter extinction of cocaine-CPP. For this, male Wistar ratstrained to acquire and then to extinguish cocaine-CPP werestereotaxically implanted with self-built microdialysis probes.The next day, GLU dialysate samples were collected in theexperimental room, first in the home cage to determinebasal levels and then in the cocaine-paired context afterthe exposure to restraint stress (30 min). Dialysate sampleswere quantified by HPLC coupled with electrochemicaldetection. Results indicate that animals submitted torestraint stress showed a significant increase in extracellularGLU levels in NAc Core during the first 15 min of re-exposureto cocaine-paired context, while the non-stress groupdid not show such increase. These findings are explained inthe framework of a dysregulation of GLU homeostasisinduced by stress and provide neurochemical basis to investigatemechanisms underpinning relapse.