RESTRAINT STRESS-INDUCED ENHANCEMENT OF GLUTAMATE TRANSMISSION WITHIN NUCLEUS ACCUMBENS CORE AFTER EXTINCTION OF COCAINE-CONDITIONED PLACE PREFERENCE: AN IN VIVO MICRODIALYSIS STUDY

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

Córdoba

Congreso; XXXIII Congress of the Argentine Society for Research in Neuroscience; 2018

Argentine Society for Research in Neurosciences

Stress is considered an important factor that induces relapse in human addicts and in animal models of addiction. Findings of our lab demonstrated pharmacologically the role of glutamatergic transmission within Core, and not Shell, subcompartment of nucleus accumbens (NAc) in restraint stress-induced reinstatement of extinguished cocaine- conditioned place preference (CPP). The present in vivo microdialysis study aims to evaluate the effect of a single restraint stress session on extracellular levels of glutamate (GLU) in NAc Core during a re-exposure to the drug-paired context after extinction of cocaine-CPP. For this, male Wistar rats trained to acquire and then to extinguish cocaine-CPP, were stereotaxically implanted with self-built microdialysis probes. The next day, GLU dialysate samples were collected in the experimental room, first in the home cage to determine basal levels and then in the cocaine-paired context after the exposure to restraint stress (30 min). Dialysate samples were quantified by HPLC coupled with electrochemical detection. Results indicate that animals submitted to restraint stress, showed a significant increase in extracellular GLU levels in NAc Core during the first 15 min of re-exposure to cocaine-paired context while the non-stress group did not show such increase. These findings could be explained in the framework of a dysregulation of GLU homeostasis induced by stress and provides neurochemical basis to investigate mechanisms underpinning relapse.