Influence of chronic restraint stress on cocaine-induced glutamate release in the nucleus accumbens

GUZMAN A; AVALOS, M.P.; GARCIA KELLER C; BOLLATI FLAVIA; CANCELA LM.

Mar del Plata, Buenos Aires, Argentina

Congreso; XXXII Congreso de la Sociedad Argentina de Investigación en Neurociencia; 2017

Sociedad Argentina de Investigación en Neurociencias

Cross-sensitization between stress exposure and drugs of abuse may be explained by long-term neurobiological changes in the mesocorticolimbic dopamine (DA) and glutamate (GLU) transmissions; specifically, within Nucleus Accumbens (NAc) Core, the major limbic-motor integration area. In this sense, previous results from our lab have demonstrated that after two weeks of a single pre-exposure to restraint stress a challenge of cocaine induced locomotor sensitization and a parallel increase in extracellular DA levels in NAc Core meanwhile GLU levels following drug were not modified. The present study attempted to determinate the long-term effect of chronic restraint stress pre-exposure in extracellular levels of GLU in NAc Core in response to cocaine. Wistar rats were exposed to chronic (2h for 7 days) restraint stress and two weeks after the last stress session, all animals were implanted with probes of microdialysis in NAc Core. The day after surgery, GLU dialysate samples were collected and quantified by HPLC. After administration of cocaine (15 mg/kg, i.p.), animals pre-exposed to stress did not show an increase of the level of extracellular GLU in NAc Core similarly to our previous results obtained following acute stress. These findings could be explained in the framework of the dysregulation of GLU homeostasis induced by stress. The current study provides neurochemical basis in order to investigate the mechanisms underpinning the comorbidity between stress and drug abuse